SDR10 Papers and Presentations
30 November - 3 December 2010
Washington, DC

Comprehensive downloads:

Presentation Abstracts:

(paper and presentation download links next to session title)

30 November 2010

Tutorial 1C: ETSI (paper) (presentation)
Markus Mueck, Infineon Technologies Germany, and Andrea Lorelli, ETSI France

The objective of this tutorial is to enable the participant

• To understand the ETSI framework with a particular focus on the ETSI Reconfigurable Radio Systems (RRS) Technical Committee. Information will be given on the possible deliverables to be produced (Technical Reports (TR), Technical Specifications (TS), European Norm (EN), etc.) and the possibilities for interacting with ETSI RRS;

• To understand the ETSI RRS vision related to Cognitive Radio (CR) and Software Defined Radio (SDR). In particular, the proposed solutions elaborated in the various Working Groups (WGs) are detailed and discussed: o WG1 focuses on "System Aspects" and develops proposals from a system aspects point of view for a common framework in TC RRS with the aims to guarantee coherence among the different TC RRS WGs and to avoid overlapping and gaps between related activities; o WG2 focuses on SDR technology with a particular interest in "Radio Equipment Architecture" and proposes common reference architectures for SDR/CR radio equipments (mobile handset devices, radio base stations, etc.), related interfaces, etc; o WG3 focuses on "Cognitive Management and Control"; the group collects and defines the system functionalities for Reconfigurable Radio Systems which are related to the Spectrum Management and Joint Radio Resource Management across heterogeneous access technologies. Furthermore, the group has developed a Functional Architecture for the Management and Control for Reconfigurable Radio Systems as well as a report on the Cognitive Pilot Channel as an enabler to support the management of the RRS; o WG4 focuses on "Public Safety" and collects and defines the related RRS requirements from relevant stakeholders in the Public Safety and Defense domain. The group defines the system aspects for the applications of RRS in Public Safety and Defense. In the framework of this tutorial, it will be illustrated how ETSI RRS will complement ongoing effort in other bodies (building on the structure outlined above), such as IEEE standardization bodies, by proposing technological solutions beyond the existing scope (related to SDR interfaces, CR specific Management and Control architectures and interfaces, knowledge management via a Cognitive Pilot Channel and Security solutions); furthermore, ETSI RRS fulfills a key role in the framework of European Regulation, with a focus, among other aspects, on the following: - The R&TTE Directive regime in force in Europe is based on declaration of conformity and does include neither type approval nor registration of the equipment nor equipment identifier (in the US, type approval is still necessary). This self-declaration is preferably a reference to a Harmonised Standard to be developed by ESTI RRS. - Protection of TV bands: In Europe, DVB-T does not show a residual carrier as it is the case in the US (the possibility for detection of the US ATSC signal below noise (i.e., at -114 dBm) is made possible thanks to the residual carrier which is present in the ATSC signal). A corresponding adaptation of sensing based standards needs to be defined for Europe. - Broadcasting, wireless microphones and assignment to radio stations are managed in Europe at the national level. Any sharing scheme based on a database will require some level of integration of the national data. In order to address the above and other European Regulatory aspects, the Electronic Communications Committee (ECC) within the European Conference of Postal and Telecommunications Administrations (CEPT) has set up the SE43 group working on "Technical and operational requirements for the operation of cognitive radio systems in the 'white spaces' of the frequency band 470-790 MHz". ETSI RRS is the competence center within ETSI to implement those regulatory requirements.

• To understand ongoing interactions with regulatory bodies and possibilities for impacting related actions via ETSI RRS; • To understand the most relevant future study axes, related to commercial and military related applications of CR and SDR.

Workshop 1F: Public Safety Communications (available presentations)

Session 2A:SCA (available papers and presentations)

A SCA-Compatible Public Safety P25-FM3TR-VoIP Gateway (Best of R&D Track)
Zhongren Cao (University of California, San Diego) 

Future public safety protection and possible disaster relief operations require the coordination of multiple government civilian agencies as well as military forces. The organization of these activities most likely will be geographically distributed. A key technology to coordinate this kind of operation is a radio gateway that enables bridging between various legacy and modern communication systems to facilitate the operation of a heterogeneous network. This paper discusses the design, implementation and evaluation of an SCA compliant P25-FM3TR-VoIP gateway. Project 25 (P25) is the standard public safety radio waveform adopted in the US. FM3TR is an open military test waveform representative of military radio systems. And voice over IP (VoIP), which carries voice packets over the IP network, is a widely used modern networking application. The objective of this gateway is to allow a user on a P25 handset to communicate with another user on an FM3TR system and vice versa. Both P25 and FM3TR users can communicate with VoIP clients located anywhere on the Internet. The full paper will cover the detail design of the P25-FM3TR-VoIP gateway and the SCA-compliant implementation of both the P25 and the FM3TR waveforms on the SDR-4000 platform from Spectrum Signal Processing. Two separate SDR-4000 units run P25 and FM3TR systems, respectively, in the gateway. The gateway also includes a SIP/VoIP server, hosted on a Linux PC, which has audio connections to and from both P25 and FM3TR sides of the gateway. All together, they constitute the P25-FM3TR-VoIP gateway. The full paper also will introduce the lab demonstration setup of the P25-FM3TR-VoIP gateway. To test the design and implementation, a third SDR-4000 operates as an independent FM3TR system which communicates with the FM3TR side of the P25-FM3TR-VoIP gateway. A commercial P25 handset is used to communicate with the P25 side of the gateway. An VoIP client running on iPhone is used to talk to the P25 or the FM3TR user through the gateway. Performance evaluation and measurement will be reported and discussed.

A Path Toward Cost-effective SCA Compliance Testing
James Ezick; Jonathan Springer; Vassily Litvinov; David Wohlford (Reservoir Labs, USA)

We present R-Check™, a versatile architecture used to develop R-Check SCA, an SCA-specific static-analysis-based compliance testing tool for software radio waveforms. R-Check SCA was developed for JTEL and is intended to provide a cost-effective replacement for several of their search-and-inspect-based compliance testing procedures. The R-Check architecture makes uses of several off-the-shelf components and open standards and is specifically engineered to integrate into the widest possible range of vendor development environments, an essential feature for addressing a modest but heterogeneous market space such as software radio. R-Check is capable of functioning over both complete and incomplete code bases and is efficient enough to run as part of the everyday edit-recompile-test cycle.

How Different Messaging Semantics Can Affect SCA Waveform Applications (Best of R&D Track)
Steve Bernier (The Communications Research Centre Canada, Canada)

Software Communications Architecture (SCA) compliant radios typically contain a large number of software components. Some software components provide access to hardware devices while others perform signal processing. By interacting with each other, the software components implement a radio link. To interact, the software components use middleware called CORBA. With CORBA, each interaction between two components is carried out as an exchange of messages between the components. CORBA standardizes the message structures which can be mapped to different communication transports. CORBA supports at least two messaging semantics: synchronous and oneway. The programming interfaces being used for JTRS radios rely on synchronous messaging. However there is a perception in the SCA community that oneway messaging can offer better performances. This paper explores the differences between the two semantics of messaging and provides performance metrics. It also describes common pitfalls associated with oneway messaging.

Implementing a generic Front Panel for An SCA Radio
Serge Harnois (Ultra Electronics - Tactical Communication Systems, Canada); Steve Bernier (The Communications Research Centre Canada, Canada)

One of the key benefits of the SCA specification is that it standardizes how software applications are installed, launched, and controlled. The specification describes a number of programming interfaces used to control software components. Every SCA application can be controlled using the same programming interfaces. Thanks to the standard interfaces, it is possible to implement generic tools to monitor and control SCA-compliant platforms. Such tools run on a personal computer and provide a fine level of control over a radio. However, in most cases, it is not practical to control a radio via a personal computer. Also, radio operators don't always need the most detailed level of control. This paper explores how a radio user interface can be implemented without the use of a personal computer and still be generic.

Session 2B: Cognitive Radio I (available papers and presentations)

Multi-Level Modeling and Simulation of Cognitive Radio Equipments
Stephane Lecomte (Technicolor, France); Christophe Moy (Supelec, France); Pierre Leray (IETR/Supelec Campus de Rennes, France)

Introduction In this paper we propose a co-design methodology, based on a UML and Model Driven Architecture approach, in order to design embedded reconfigurable systems . We particularly focus on the design of software radio and cognitive radio equipments. A potential hardware target is System on Programmable Chip, like FPGA components, taking into account the specific capability of partial reconfiguration. A reconfiguration and cognitive management architecture (HDCRAM for Hierarchical and Distributed Cognitive Radio Architecture Management) is used in addition to the device's radio application. The system (functional architecture and hardware architecture) is modeled in UML using MARTE. Going through Model-to-Model transformation the cognitive radio equipment is first modeled at a high abstraction level first, based on the HDCRAM metamodel of, and then modeled at a lower level of abstraction in SystemC, which enables to simulate and validate the system. We illustrate the proposed concepts with a cognitive radio case study involving reconfigurable radio signal processing executed on a dynamic reconfigurable target. Context System on Programmable Chip, based on an FPGA, is a potential hardware implementation solution for cognitive radio equipments.

Modeling Cognitive Radio Performance in High Spectral Density Signal Environments
David A Leiss; Steve Sanelli (Agilent Technologies, USA)

This paper will show the methodology to model the throughput performance of a Cognitive Radio operating in a high density RF signals environment. Most modeling of SDRs and Cognitive Radios are typically done using a single, ideal, waveform. At best, some noise and multipath might be added. In the real world, Cognitive Radios must be able to function successfully in areas that can contain many different radiation sources at various power levels and frequencies. This paper will model the combined effects of a desired RF signal combined with several different measured RF spectral environments, measured on a Vector Spectrum Analyzer, all being applied to the receiver input. processed through the receiver and through the DSP as it attempts to adapt to the applied RF spectral environment.

Joint Rate and Power Control using Distributed Algorithms in Cognitive Radio Network
Uvaraj Rajasekaran; Kamran Arshad; Klaus Moessner (University of Surrey, United Kingdom)

Radio frequency spectrum is limited and highly contested, hence cognitive radio networks' perceived ability to improve spectrum utilisation has gained much attention. Joint rate and power control is a method that can be used by unlicensed secondary users to share spectrum with licensed primary users as long as it provides QoS guarantees to both secondary and moreover to primary users. In this paper, we propose a distributed joint rate and power control algorithm for infrastructure-less cognitive radio networks in which each user adjusts their transmit power and rate of transmission by considering the QoS of both primary and secondary users. We propose a fully distributed iterative algorithm in which the aggregate transmission power for cognitive radios is calculated assuming a maximum initial data rate. If the calculated power is more than the maximum allowed power level, the data rate is reduced and power is recalculated iteratively. Simulation results show that by using the proposed approach a higher number of users can be supported while the QoS constraints for both primary and the secondary users are maintained.

Complexity Analysis of Systematic Spectrum Sensing for Cognitive Radio
Jui-Chieh Lin; Min-Jung Fan-Chiang; Sao-Jie Chen (National Taiwan University, Taiwan); Michael Schulte; Yu Hen Hu (University of Wisconsin-Madison, USA)

Spectrum sensing techniques for cognitive radio (CR) provide the opportunity to utilize the radio spectrum more efficiently. Recently, spectrum sensing techniques, such as energy detection, cyclic prefix detection, and the spectral correlation function (SCF), were proposed and analyzed. Various state-of-the-art, ad-hoc spectrum sensing techniques have been implemented on different platforms including GPUs, ASICs, and DSPs. Over time, sensing techniques have evolved to achieve higher accuracy and obtain more information. Systematic spectrum sensing approaches, which employ a combination of different ad-hoc spectrum sensing techniques, have recently been proposed. However, the implementation of these systematic spectrum sensing approaches has not yet been explored. Our work provides an early study of systematic spectrum sensing approaches.

A Survey of Basic Channel Selection Techniques for Cognitive Radios
Benjamin C. Hilburn; Timothy R. Newman; Tamal Bose (Virginia Tech, USA); Shubha Kadambe (Rockwell Collins, USA)

Many applications of cognitive radios require the system to dynamically choose a channel on which to operate, often within a relatively small time constraint. The optimal channel selection strategy for such applications is an area of high interest to researchers, and there are numerous recent publications that propose new techniques. Most of these techniques are targeted at different network and channel models, which span from a pair of dynamic spectrum access radios to large-scale cognitive radio networks. While the detailed internals of each method differ, they can still be organized into a smaller set of general strategies, and many of them are based on very simple strategies that are computationally non-complex. In this paper, we give a survey of some basic channel selection techniques that have appeared in recent literature, and simulate each of them. We also present a simulator that we created, named the 'Universal DSA Network Simulator', which we use to model each of the channel selection techniques. The material in this paper is novel in that, to the authors' knowledge, there does not exist a published comparison of fundamental channel selection techniques. Our work will serve as a strong starting point for research and algorithm development in the channel selection area.

Session 2C: Education and Radio Challenge (available papers and presentations)

Teaching Digital Communications in a Developing Country using a Low Cost Software Defined
Yair Linn (Universidad Industrial de Santander, Colombia)

Developing countries, depending on the definition used, contain upwards of 80% of the world's population. Regrettably, teaching of engineering topics in developing countries is often hampered by the lack of funds (as compared to developed countries). In this context, teaching of digital wireless communications courses, an essential component of any electronic engineering curriculum, often suffers in developing countries from the lack of modern laboratory equipment necessary for adequate teaching of the subject. In this paper we shall outline a methodology for the teaching of digital communications courses in the senior undergraduate level in the Universidad Industrial de Santander, in Bucaramanga, Colombia, South America. The author will outline his experiences in teaching such courses as a visiting professor from Canada, using two low cost Software Defined Radio laboratories developed by the author (costing US$200 and US$500, respectively).

SDR in Undergraduate Engineering Education
Vuk Marojevic; Antoni Gelonch; Ismael Gomez (Polytechnical University of Catalonia, Spain); Joan Olmos (Universitat Politecnica de Catalunya, Spain); Gabriel Montoro (Technical University of Catalonia, Spain)

While technology develops quickly, one of the major goals in University education is to provide the students a clear view of the complexity of current and emerging systems, while offering enough background to understand and be able to participate in this development. Wireless system engineering, in particular, requires knowledge of emerging technologies and skills in many methodologies, such as digital signal processing, software design (programming in C and VHDL), real-time execution, parallel and distributed computing, digital-to-analog conversion, and so forth.

RF environment behavior modeling based on 3-D Ray-Tracing and Neural Networks to mitigate
Fermin Esparza Alfaro; Meenakshi Rawat; Ramzi Darraji; Karun Rawat; Seyed Aidin Bassam; Fadhel Ghannouchi (University of Calgary, Canada); Victor Torres; Francisco Falcone (Universidad Publica de Navarra, Spain)

The existing emergency networks require highly accurate position estimation of the rescuers to properly coordinate the rescue operations. This requires a robust RF environment modeling of the disaster scene which becomes crucial when considering the indoor position estimation. The indoor environments are mainly characterized with strong multipath behavior where the multipath components can be more powerful than the direct path signal compromising the accuracy of the estimated position. Since the multipath problem dominates most of the environment characteristics in such indoor environment, an RF model is proposed to characterize the behavior of channel using neural network with the three dimensional (3-D) Ray-Tracing technique. This model can be used to configure the adaptive beam-forming of smart antennas in order to maximize the beam of direct path between the emitter and the receiver and to reduce the strong multipath components.

Packet Detection, Frequency Synchronization, and Channel Estimation/Equalization of Reconf
Mohammad Mojtaba Ebrahimi; Seyed Aidin Bassam; Ramzi Darraji; Mohamed Helaoui; Fadhel Ghannouchi (University of Calgary, Canada)

This paper demonstrates the development and implementation of packet detection, frequency synchronization and channel estimation/equalization blocks of an OFDM-based standard, such as WLAN and WiMAX, receivers. The proposed solution is prototyped on DSP/FPGA platform and the performance of the solution is evaluated using the WLAN signal.

Feature Extraction Methods on a Novel Modulation Classification Technique for Cognitive
Okhtay Azarmanesh; Pradyumna Desale; Chris Gardner; Sven G. Bilén (The Pennsylvania State University, USA)

We report here a full model of a novel Modulation Classification (MC) technique and its implementation on USRP boards. This model includes a way of estimating the location of the signal transmitters using angle of arrival (AoA) techniques and performing a full MC process on the signal and extracting the parameters and the data. We will be investigating the low computationally complex angle of arrival methods, based on subspace reduction using Multi Stage Wiener Filtering. Comparison is based on accuracy, the length of training sequence and performance in presence of strong interferer and multi path fading. This report also includes a study on Gaussianity tests to find the most efficient way of classifying single-carrier versus multi-carrier signals that would be computationally less complex and more resilient to white Gaussian noise. Further implementation and refinement of the novel single-carrier MC technique using I-Q diagram of modulations will be discussed.

Workshop 2E: Open Source in Military and Commercial Wireless (available presentations)

Workshop 2F: Public Safety Communications (available presentations)

1 December 2010

Session 3A:Security  (available papers and presentations)

Instruction Set Extensions for Accelerating SNOW 3G on a Multithreaded Software Defined
Chris Jenkins (University of Wisconsin--Madison, USA); John Glossner (Sandbridge Technologies, USA)

Software-defined radio (SDR) is an emerging technology that facilitates having multiple wireless communication protocols on one device. Previous work has shown that physical layer processing for current wireless communication protocols can execute on this class of device while consuming significant processing power. Emerging wireless protocols, such as HSPA+ and LTE, will require data rates above 100 Mbps and secure communications. This paper presents instruction set architecture (ISA) extensions and hardware designs for the SNOW 3G cipher. SNOW 3G provides encryption on the cellular channels present in UMTS and future systems. Our proposed ISA extensions provide significant performance and energy benefits when implementing SNOW 3G on programmable SDR platforms.

Settling a SDR reference security architecture
Rafael Aguado (Indra Sistemas S.A., Spain)

Good things about standards is you have a lot to choose from Although this quote used to end my emails 15 years ago is not only valid, but truer. Nowadays, the SDR development is crossing the line from the standard reference platform to a differnt-solutions-to-cover-all-possibilities approach. This decision is clearly focused on the improvement of the overall radio performance, but on the other side, the portability, the cost effectiveness, all the goals that drove the SCA development can get lost on this web of different possibilities. This problem is getting more complicated if the solutions are referred to security. Trying to mitigate this situation, the paper will present the development of a reference implementation for a security architecture. In order to achieve the objective, a set of well established standards has been used. Nevertheless, and strictly following the aforementioned standards, some improvements are presented in other to work around the national-defined solutions.

Session 3B: Cognitive Radio II (available papers and presentations)

Robust Cyclic Cumulants Based Multiuser Automatic Modulation Classifier For Cognitive Radio
Barathram. Ramkumar; Tamal Bose (Virginia Tech, USA); Miloje Radenkovic (University of Colorado at Denver and the Health Sciences Center, USA)

Cognitive Radio (CR) is an emerging wireless communications technology that addresses the inefficiency of radio spectrum usage. The automatic modulation classifier (AMC) is an important signal processing component that helps the CR in identifying the modulation format employed in the detected signal. AMC algorithms developed so far can classify only signals from a single user present in a frequency band. In a typical CR scenario, there is a possibility that more than one user is present in a frequency band and hence it is necessary to develop an AMC that can classify signals from multiple users simultaneously. In this paper we propose a novel multiuser AMC based on higher order cyclic cumulants of the received signal. The proposed AMC is developed for more realistic multipath fading environments and no assumption on the transmission power of the users is made. Also the proposed AMC does not require any prior knowledge about the channel. Simulation results are provided to illustrate the promising results yielded by the proposed algorithm.

Prototype of a Spectrum Sniffer Software Implementation for ISM Bands
Ermano Picco (ST Microelectronics, Italy)

In a Software Defined Cognitive Radio the goal to exploit at maximum the under-utilized spectrum portions can be achieved only performing reliable spectrum sensing. This is obtained through a tunable full software implementation of cyclostationary spectrum sensing algorithms running on a reconfigurable, programmable SoC that embeds a core subsystem dedicated to the sensing routines. The engine will be used as a proof of concept to test on the field the baseband sensing algorithms.

Evaluation Optimization Techniques for Software Defined Radio - Cognitive Radio System
Nikhil Challa; Jeong-O Jeong; Carl B. Dietrich; Timothy R. Newman; Jeffrey Reed (Virginia Tech, USA)

This paper will evaluate performance of optimization techniques to tune radio system parameters to improve performance efficiency. The problems faced by radio systems are the ability to maintain system performance efficiency without relying on predefined relationships between different tunable parameters and observables. While cognitive radios are considered well suited for dynamic spectrum access applications, optimization of radio performance in general can benefit from a self learning system rather than relying on pre-existing equations to predict system performance. This paper uses the Open Source SCA Implementation Embedded (OSSIE), and Cognitive Radio Open Source System (CROSS), developed by Virginia Tech, for demonstration purposes.

A Cognitive Radio Prototype For Spectrum Sensing Application
Michael Steiner; Tamal Bose; S M Hasan (Virginia Tech, USA); Sam Shearman; Ahsan Aziz (National Instruments, USA)

This paper describes the implementation of a prototype cognitive radio for performing real-time spectrum sensing using cyclostationarity detection methods. This prototype has been developed and implemented using National Instruments real time hardware platform and LabView software platform. The developed prototype demonstrates a cognitive radio node capable of identifying white-spaces (unused portions of the frequency band) in the given frequency spectrum and efficiently utilizing these for communications.

Collaborative Adaptation of Cognitive Radio Parameters Using Ontology and Policy Approach
Shujun Li; Mieczyslaw Kokar; David P. Brady; Jakub Moskal (Northeastern University, USA)

Cognitive radio is expected to be aware of the changing channel environment and adjust the services and resources accordingly by changing the radio's transmission parameters. In order to achieve automatic adaptation, the radio must have the ability to reason about the facts from the environment or from other radios/nodes, i.e. to infer implicit knowledge from the explicitly represented knowledge. It requires a proper language to represent the knowledge and policies and an inference engine that can process the knowledge and policies. However, such awareness and reasoning capabilities, especially combined with optimization and adaptation, have not been previously reported in the literature. Ontology-Based Radio (OBR) has shown its potential to fulfill the awareness and reasoning requirement of cognitive radio. We aim to refine the OBR concept and apply it to a link optimization use case. The general goal is to maximize the information bit rate per transmitter watt of power.

Session 3C: Communications Signal Processing I (available papers and presentations)

Polyphase Filter Bank with Unequal Bandwidths and Unequal Spectral Centers
fred harris (San Diego State Univ, USA)

Traditional M-Path channelizers are multichannel filter banks with identical bandwidths and equal spaced center frequencies. Many applications desire channelizers with unequal channel bandwidths and with non-equally spaced channel centers. A simple example is a cable plant which may have a mix of 6 MHz and 8 MHz channels distributed over its frequency span with select odd width channel slots interspersed in the frequency band at specific legacy center frequencies. We have developed two methods that permit a modified channelizer to accommodate baseband shaped channels of any bandwidth and position them at arbitrary center frequencies.

Polyphase Filter Bank for Unequal Channel Bandwidths and Arbitrary Center Frequencies-I
Xiaofei Chen; fred harris (San Diego State Univ, USA); Elettra Venosa (Seconda Università degli Studi di Napoli, Italy)

The conventional M-Path channelizer is an extremely efficient structure to down convert M equally spaced channels with fixed bandwidths. Many applications require the receiver to demodulate spectra containing multiple signals with unequal bandwidths and arbitrary center frequencies. We have developed two methods that permit a modified demodulator channelizer to simultaneously down convert multiple signals with different bandwidths and arbitrary center frequencies.

Polyphase Filter Bank for Unequal Channel Bandwidths and Arbitrary Center Frequencies-II
Elettra Venosa (Seconda Università degli Studi di Napoli, Italy); Xiaofei Chen; Fred Harris (San Diego State Univ, USA)

The conventional M-Path channelizer is an extremely efficient structure to down convert M equally spaced channels with fixed bandwidths. Many applications require the receiver to demodulate composite signals containing multiple spectral band signals with unequal bandwidths and arbitrary center frequencies. We have developed two methods that permit a modified demodulator channelizer to simultaneously down convert multiple signals with different bandwidths and arbitrary center frequencies. We report on the first of the two methods here. The proposed structure is composed by a modified M-path channelizer and a signal synthesizer. The standard M-Path polyphase filter with its associated M-Point IFFT channelizes the input spectrum sampled at fs, and down-converts the channelized signals to the baseband with an output sampling rate fs/M at each output port.

Reception Performance of Flexible Wireless System Receiving Multi-Signals Simultaneously
Hiroyuki Shiba (NTT, Japan)

We have proposed flexible wireless system that employs our software defined radio technology and cognitive radio technology. This system is a unified wireless platform that can support various wireless systems flexibly and allow new wireless services to be rapidly implemented. We also implemented the system prototype as a first step towards realizing the proposed wireless platform. This paper focuses on simultaneous multi-signals reception of flexible wireless system. To receive multi-signals at the same time, we proposed and implemented two signal processing methods on our prototype. One is signal separation method based on feature amount of received radio wave data and another is auto gain control method for various wireless systems. We evaluated the signal separation method and auto gain control for multi-signal reception simultaneously in the flexible wireless system. In the following final paper, we will describe two our methods more in detail.

Workshop 3D: Regulatory (available presentations)

Tutorial 3E: IPA (presentation)
Presented by Peter G. Cook, Hypres, Inc., USA, and James Neel, Cognitive Radio Technologies, LLC, USA

Information Systems are having a profound impact on our society, invoking great changes, with an impact similar to those brought about by steam power, electricity, and electronic communication. Communication Systems are a major item of interest for the Wireless Innovation Forum. We are also looking at the consequences of system expansion that leads to intersection, interaction, and integration of independently developed systems, and the resulting Complex Systems. As the means by which data is exchanged between system participants , the role of Communication Systems can best be understood in context of the architecture of Complex Systems. The Cognitive Radio Working Group and the Public Safety Special Interest Group recently released volume 1 of the Information Process Architecture (IPA) project - a multi-part effort to improve understanding of how information and communications systems are evolving to exhibit increasingly intelligent behavior, grow to interact with one another, and enable new applications and capabilities. Future work will further refine these concepts, develop new applications, and further explore how understanding context can improve the performance of automatic information systems. In this tutorial we cover the work to date of the IPA project and describe our future plans. 

Tutorial 3F: Two-Thirds of SDR is SD (paper and presentation)

Tutorial 3G: A Graphical Approach to FPGA Programming (paper)

A graphical approach to FPGA programming
Christian Amadasun (National Instruments, USA)

Domain experts are often stifled by the complexities of programming field-programmable gate arrays (FPGA's). Development can get bogged down by the lack of experience with low level hardware languages such as VHDL and/or Verilog. Digital design engineers are often integrated into the development team and are employed to design custom FPGA boards, this further complicates development and increases the length of the development cycle. Through-out the session the use of the software environment as well as code samples will be presented. The session is ended with a simple hardware and software demonstrated.

Session 4A: System Implementation and Test I (available papers and presentations)

Insights into building an SCA Test Laboratory (Invited Presentation)
Randy Navarro (SAIC, USA)

A feature and portion of a Software Defined Radio (SDR) is abiding by the principals of the Software Communications Architecture (SCA). To ensure an SDR conforms to SCA principals, an independent-third party, test laboratory must verify and validate the SDR. The test laboratory must have well defined test methodologies and well developed tools to efficiently and accurately assess that SDR adheres to the SCA. Although, the SCA specification is widely available, the information on how to establish, and sustain testing an SCA based SDR is not. The immediate objective of this paper is to provide general insights and an understanding how an SDR test lab accomplishes its testing efforts. For example, experienced test engineers know many tasks are required before testing can begin. Therefore, one objective of this white paper is to provide a description and explanation of the foundational process required to ensure effective and efficient testing of an SDR. This paper will provide useful information for understanding what the SCA based SDR test lab accomplishes before, during and after testing an SCA based SDR.

Hardware-in-the-Loop Design Verification Testing for Software-Defined Radio Waveforms
Ying Niu; David Mussmann (Raytheon, USA)

This paper describes a hardware-in-the-loop (HWIL) test environment for a software-defined radio (SDR) wideband OFDM waveform implemented in an FPGA. This environment executes the radio waveform on a COTS board that fits in a PCI slot in a PC backplane. PC software executes the waveform and compares the implemented waveform performance (BER, PER, packet synchronization, etc) against theoretical results. Graphical user interface permits the user to select functions to be tested and allow the user to swap firmware and software implementations of functions. Compared to waveform testing in target hardware, this environment expedites design verification testing. The environment enables design verification testing for complex waveforms over the complete range of waveform modes. In this environment, the user can calibrate digital baseband samples or digital modem IF samples for range delay and attenuation, fading, Doppler, and phase rotations. The environment also provides the ability to measure FEC (forward error correction) performance. Additionally, the environment also provides a platform for functional testing outside the target hardware.

Implementation of Smart Antenna and Transceiver API on OSSIE Platform for Wireless
Chiyoung Ahn; June Kim; SeungWon Choi (Hanyang University, Korea)

This paper presents an implementation of WIF (Wireless Innovation Forum) standards of SA(Smart Antenna) API (Application Programming Interface) and Transceiver API using OSSIE(Open-Source SCA Implementation-Embedded). Through our implementation, it is verified that the standard SA API can be utilized in any of SCA(Software Communication Architecture)-based SDR(Software Defined Radio) systems. Using our implementation, we also verify that the Transceiver API can be realized with a commercial RF solution such as USRP2(Universal Software Radio Peripheral). SA API consists of algorithm facilities, synchronization facilities and control facilities. It is noteworthy that the algorithm facilities in the SA API enables various functionalities of array antenna system such as beamforming, space-time coding and MIMO of spatial multiplexing, which are core technologies in 4G mobile communication system. In order to support the array antenna structure, Transceiver API should first be extended into multichannel, of which details are shown in our implementation. OSSIE, on which every procedure of our implementation is based, provides the SCA framework as well as tools for developing SCA waveform. Our implementation could be used as a milestone for proceeding further standardization of both SA API and Transceiver API for other organizations such as ETSI, JPEO, etc, besides WIF.

Rapid Prototyping of a SDR Based Reconfigurable MIMO-OFDM Testbed
Sabares Moola; S M Hasan; Carl B. Dietrich; Jeffrey Reed (Virginia Tech, USA)

This paper describes the integration of a multiple input multiple output (MIMO)-orthogonal frequency division multiplexing (OFDM) testbed, which uses field programmable gate arrays (FPGAs), into an software communication architecture (SCA) platform called open source SCA implementation embedded (OSSIE). We demonstrated the capability of reconfiguring an FPGA platform dynamically through the software framework OSSIE for the operation of different standards such as IEEE 802.16e (Mobile WiMAX) and IEEE 802.11a (WLAN). The MIMO-OFDM testbed has been created as a prototype for testing different kinds of software defined radio (SDR) applications. This paper presents detailed description of the development of this MIMO-OFDM testbed using FPGA and its integration into the OSSIE framework. The proposed testbed will acts as a open source platform for standards like IEEE 802.11a and IEEE 802.16e. MIMO techniques employ multiple antennas at the transmitter and receiver to facilitate operation of high data rate applications over the scarce spectrum. High spectral efficiency and effective mitigation of frequency selective multipath fading can be achieved using OFDM in conjunction with MIMO. In this paper, we have implemented the Alamouti space time block code, a simple transmit diversity technique.

Session 4B: Cognitive Radio III (papers) (presentations)

Grey Systems Theory Applications to Wireless Communications (Best of R&D Track) 
Ashwin Amanna; Ratchaneekorn Thamvichai; Matthew J Price (Virginia Tech, USA)

This paper discusses Grey Systems Theory (GST) towards wireless communications and its applications. Grey Systems Theory consists of information theory concepts and a practical algorithm developed in the 1980's to address situations where information is incomplete and affected by random uncertainties. The paper focuses on two GST concepts, Grey Relational Analysis (GRA) and Grey Prediction Theory. GRA provides a method to quantify the similarity between a reference data series and set of data. Grey Prediction Theory is used for modeling time series data and enables prediction of future values with limited data points and unknown probability distributions. We first survey the current research in GST within wireless communications. This paper will also introduce an application of GRA to implement a novel Automatic Modulation Classification (AMC) algorithm, an important component in cognitive radio. GRA is also discussed as an alternative method to Euclidian distance for quantifying similarity in a case-based reasoning decision maker for cognitive radio.

Cognitive Radio Testbed - Real-World Electromagnetic Spectrum Survey, Modeling
Trang Mai; Christopher R. Anderson; Joseph Molnar (Naval Research Laboratory, USA)

The radio electromagnetic spectrum is a precious resource that is governed and licensed by governments for uses in radio communications. Electromagnetic radio spectrum is limited and currently statically allocated throughout the world, resulting in simply an insufficient amount of spectrum to meet the growing demands by both commercial and military users. Spectrum sensing Cognitive Radios (CR), also known as Dynamic Spectrum Access (DSA) radios, are an emerging technology that promises greater efficiency in utilizing the available wireless spectrum.

A Sub-Space Method to Detect Multiple Wireless Microphone Signals in TV Band White Space
Dinesh Datla; Harpreet S Dhillon; Jeong-O Jeong; Michael Benonis; Michael Buehrer; Jeffrey Reed (Virginia Tech, USA)

Hurdles still remain in the realization of dynamic spectrum access (DSA) systems due to the uncertainty associated with spectrum sensing at extremely low signal to noise ratio (SNR) conditions. One such challenge is to detect the presence of wireless microphones (WMs) in the TV band. In this paper, we propose a method for detecting the presence of multiple narrow-band analog frequency-modulated signals that are generated by WMs. In addition, the algorithm can determine the center frequencies of multiple signals. We use real WM signals experimentally captured under low SNR conditions to verify the detection performance of our algorithm.

Applying Cognitive Radio Concepts to Next Generation Electronic Warfare
Randall Janka (Zeta Associates, USA)

The vision and technological aims of software defined radio (SDR) in general and cognitive radio (CR) in particular are not that dissimilar from those of modern electronic warfare (EW). SDR is all about a flexible platform that can intelligently manage its own resources. CR has been defined in the SDR Forum's SDRF Cognitive Radio Definitions (SDRF-06-R-0011-V1.0.0; approved 8 November 2007) as "radio in which communication systems are aware of their environment and internal state and can make decisions about their radio operating behavior based on that information and predefined objectives." RF environment awareness is understanding what is going on in the spectrum. This paper will discuss the overall system HW and software SW architecture, resource and system awareness, how user policy constrains the autonomous high-level planning and low-level scheduling, the families of algorithms developed, and an overview of their performance.

Session 4C: Communications Signal Processing II (available papers and presentations)

On Frequency Lock Detection for Low Signal-to-Noise Ratio (SNR) QAM Signals
Doan Nguyen Vo (Ultra TCS, Canada); Steve Ricard (Digital/Analog Specialist, Canada)

This work proposes a new approach on the frequency lock detection suitable for high QAM modulations which are widely used in many reconfigurable Software-Defined-Radio (SDR) systems. This work contains a reliable mechanism to enable a radio system working under very low signal-to-noise ratio (SNR) environments, with high coding gain scenarios such as TPC, LDPC, etc. In a common SDR receiver, the modulated signal after being processed by the analog front-end (AFE) is sampled and converted into digital signal. The received signal is further processed by using digital signal processing (DSP) techniques. One of the receiver's key functions is to extract the correct carrier frequency so that a complete baseband signal could be recovered. In summary, the modem is first reset when powered up. The carrier recovery (CR) control block is in the state to initialize all parameters required by CR loop's blocks. The CR is claimed "locked" when it detects that its internal requirements exceed PASS thresholds, and the modem backend declares its frame detection being passed. In the "locked" state, the modem performs "tracking" of the parameters (frequency, phase, timing, etc.). For some unforeseen problems such as fades, jams, etc., the modem gets "unlock" state. Prior to "locked", fast operations are performed to acquire information for the parameters.

Experimental Results on All-Digital Implementation of the Phase Locked-Loop for Software
Alexandre Marsolais; Doan Nguyen Vo (Ultra TCS, Canada)

This work presents a new implementation of digital clock generation suitable for Software-Defined-Radio (SDR) applications. The field of SDR is evolving rapidly, more and more scenarios require reconfigurable radios, such as complete personality changes between customer premises equipment (CPE) to acting as an access point. One of the key features of such SDR units will be their ability to reconfigure its circuitry to meet the varying performance requirement of each individual application. For this to become reality we need to come up with hardware that meets the demand for high flexibility. The following paper presents such a flexible and necessary component of all SDR. Phase locked loop (PLL) are used to synchronize the local oscillators (LO) for up and down conversion, for symbol, bit timing in both transmit (Tx) and receive (Rx). All PLL synchronize to a reference signal either externally provided or internally generated. The proposed circuitry accepts both sinusoid and square wave references. It is insensitive to duty cycle variation. Since an SDR unit may have to switch between different mode of synchronization the PLL used must be of high performance and insensitive to varying the reference type, since the reference can vary between the output of a symbol timing recovery loop (STRL) or a condition reference source if acting as a base station. This paper presents a digital PLL (DPLL) that offers a flexible solution for SDR application in terms of loop behavior such as loop bandwidth, transient response, very fast settling time, and low phase noise transfer function.

Compensation of Symbol Clock Offset and Carrier Frequency Offset in the Multi-Band DFT
Sang Burm Ryu; Heung-Gyoon Ryu (Chungbuk National University, Korea); Jin-Up Kim (ETRI, Korea)

For the IMT2000 advanced next generation mobile communication system supporting maximum 1Gbit/s data rate in 100MHz bandwidth, the spectrum aggregation method have been recently studied how together and extend into more available frequency bands. Bandwidth utilization is increased since idle frequency bands are used to communicate. However, receiver structure is very complex. Also, the interference among the used bands makes system performance degraded when multi-band signals are received by a receiver simultaneously. Therefore, in this paper, we make a receiver simple and propose new suitable method for direct conversion receiver (DCR) demanding of existing receiving method. Proposed system makes multiplexing band by high speed clock sampling after band selection and receives DFT spreading OFDM (orthogonal frequency division multiplexing) signal as a TDM (time division multiplexing) method. So, the structure of receiver becomes simple and degradation of system performance by interferences among used bands is reduced.

Analyzing the Effect of Power Control Algorithms on the Receiver's Computing Resource
Ismael Gomez; Vuk Marojevic; Antoni Gelonch (Polytechnic University of Catalonia, Spain)

Traditional Software-Defined Radios are limited in their ability to share the computational infrastructure between different channel flows of different demands. Future terminals should move to a shared resource model to further improve resource utilization and link availability. For this purpose, an accurate characterization and prediction of the consumed resources by a new user entering the cell is important. At the receiver side, iterative channel decoding algorithms, which exhibit the highest contribution of processing time and energy consumption, consume resources as a function of the signal quality. Therefore, power control has an impact on the computing resources of the receiver. This paper presents a model to characterize the available computing resources of a receiver. This model may be useful for utility-based power control algorithms.

Performance Evaluation and Parameters Sensitivity of the OFDM modulation in HF Transmission
R. B. Dutra; A. C. Mendes (Brazilian Research Institute/ Digital Systems Group, Brazil); Mariane Rembold Petraglia (Federal University of Rio de Janeiro, Brazil)

This study examines the transmission performance over high frequency (HF) channels when OFDM modulation is employed, taking into account influences of the modulation parameters. The channel estimation is done by using pilot subcarriers in the OFDM modulation. Whereas a least squares algorithm was applied to estimate the channel frequency response in the frequencies of the pilot carriers, an interpolation technique was used to obtain the response in other frequencies. Performance comparisons were made based on bit error rate (BER) measurements considering the following parameters: total number of subcarriers, the interval between the pilot subcarriers and the modulation schemes (BPSK, QPSK, 8PSK and 16 QAM). For the channel simulation, we adopted the standard specifications of the U. S. Department of Defense, MIL-STD-188-110/B, which sets performance standards for HF data modems. The results showed that the HF transmission performance depends directly on the channel conditions and on the chosen OFDM parameters, suggesting that, to improve the performance of OFDM modulation in HF channels, the proper parameters should be selected based on the channel characteristics, which might be done in cognitive radios.

Design and Performance Tradeoffs in Digital Radio Processing Architectures
Mujun Song; Jason Pennington; Mark D. Silvius; Ryan Thomas; Richard K. Martin (Air Force Institute of Technology, USA); Charles Bostian (Virginia Tech, USA)

The level of reconfigurability in digital radios varies significantly. At one extreme, dedicated devices, using single-function analog components and dedicated digital chips, operate for a specific wireless application. These devices lack the flexibility to change or adapt to different communication requirements, waveforms, and applications. At the other extreme, software-defined radio platforms use A/D converters to sample at RF or IF frequencies, allowing reconfigurable software running on general processing architectures to operate over a wide variety of applications. While these devices may offer the most flexibility in terms of reconfigurability, they can also have significant overhead in terms of power consumption, cost, size, and performance. Between these two extremes lie firmware defined radios, a class of digital radio that is still highly reconfigurable, but uses firmware and modifiable components to adjust at what point, traditional software is run in the digital receive process. This paper investigates the tradeoffs between different processing architectures running in firmware and software. To achieve this, the paper will review current processing architectures and products on the market that are using them. Next, the paper defines a series of metrics that can be used to evaluate and compare these architectures under a typical use case. We use the results to show the potential advantages and disadvantages of these processing architectures.

Expert Lecture 4E: Equalization Techniques for Multipath Channels (paper)

2 December 2010

Session 5A: System Implementation and Test II (available papers and presentations)

DICOMT Software Defined Radio for Search and Rescue
Robin Addison; Claude Bélisle (Communications Research Centre, Canada)

In 2007, Communications Research Centre (CRC) and the National Search and Rescue Secretariat (NSS) initiated a three-year research project to develop a prototype terminal to solve the interoperability and backhaul issues at crisis sites. The Deployable Interoperable Communications Terminal (DICOMT) is a software defined radio that is able to interoperate with a number of voice protocols, as well as with satellite backhaul. It has been designed with the flexibility to define, via software, various modes of operation compatible with the equipment first responders are expected to bring to the crisis site. For the prototype, public safety analog AM and FM waveforms were selected, along with the digital TIA/EIA Project 25 waveform. The DVB-S waveform is used for the satellite backhaul. The DICOMT is able to choose a combination of waveforms at the site, allowing communications with other radios (using these waveforms), and also allowing communications bridging between radios using disparate waveforms. The prototype is implemented on the Spectrum Signal Processing SDR-4000 platform, along with a Digital Receiver Technology (DRT) radio frequency (RF) front end and some CRC developed components. SCA Devices, Nodes, Resources and Applications were developed to support the prototype. Some special-purpose Devices were developed to support run-time selection of waveform combinations. The prototype has been developed and interoperability with commercial equipment has been demonstrated.

A SDR testbed architecture for ACM, MIMO and DSA in military applications
Patrik Eliardsson; Ulrika Uppman (Swedish Defence Research Agency (FOI), Sweden)

A need for increased link capacity, in the upcoming military communication systems can be foreseen where new services such as streaming video will increase the throughput requirements. This paper describes a testbed architecture based on the GNU Radio Software Defined Radio (SDR) platform together with the Universal Software Radio Peripheral version 2 (USRP2). The architecture is constructed for implementation of techniques like Multiple Input Multiple Output (MIMO), Adaptive Coding and Modulation (ACM) and Dynamic Spectrum Access (DSA) that will increase the link capacity in military applications. The testbed is intended to verify simulated results with realistic channel conditions and environments, and to demonstrate the benefits of the mentioned technologies.

Implementation of an SDR platform using GPU and its Application to 2x2 MIMO WiMAX System
JaeHyuk Ju; Chiyoung Ahn; June Kim; Seungheon Hyeon; SeungWon Choi (Hanyang University, Korea)

Conventional communication systems have been implemented using Digital Signal Processing (DSP) and/or Field Programmable Gate Array (FPGA) especially for the Software defined radio (SDR) functionality. We propose a scheme of using Graphics Processing Unit (GPU) instead of those two conventional devices for implementing the SDR-based communication system. GPU, a high-speed parallel processor and numerous powerful arithmetic logic units, is adopted for the signal processing of physical layer required for the parallel processing of SDR system. Noting that Compute Unified Device Architecture (CUDA) based on C language provides Software Development Kit (SDK) for the modem application of GPU, we utilize the CUDA SDK to perform the modem function which operates on real-time basis. This paper presents an implementation of 2x2 Multi-Input Multi-Output (MIMO) WiMAX system using GPU as its modem. Mounting an RF module on top of our GPU modem, we demonstrate a real-time transmission of video data. The system performance of our GPU-based system is shown in terms of operation time.

A Real-Time Algorithm Design and Prototyping Platform for MIMO Research
Murat Torlak; Douglas E Kim; JIN Yuan (University of Texas at Dallas, USA); Sam Shearman (National Instruments, USA)

In this paper, we present the design of a comprehensive real-time algorithm development platform for MIMO communication systems based upon the highly customizable FlexRIO hardware platform by National Instruments. By using a commercial off-the-shelf system with a programming environment familiar to many in industry and academia, we seek to reduce costly development time and instead enable researchers to focus on algorithm development and analysis tasks. As a demonstration of the FlexRIO's capabilities, we present our preliminary findings on an experimental bit error rate (BER) performance comparison between a 2[1]1 OFDM system employing Alamouti space-time coding and another 1[1]1 OFDM system which does not. A detailed examination of the two systems' wireless channel characteristics and their impact on BER performance is also presented.

Tutorial 5B: Emerging Commercial Wireless and Cognitive Radio Standards (presentation)
James Neel, Cognitive Radio Technologies, LLC, USA

Rather than converging to a common protocol, the number of wireless standards continues to explode. While SDR is enables the move to multimode devices (even octo-mode devices), just staying abreast of all of the standards is a full time job. This tutorial is intended to help the audience keep track of the wireless world by briefly touching on critical aspects of emerging wireless standards. 

Session 5C: Waveform and Software Design I (available papers and presentations)

Radio Waveform Development System providing an integrated approach to SDR Waveform Design
Nirali Patel; Kevin Shelby; Brian A. Dalio (Coherent Logix, Inc., USA)

We present the Radio Waveform Development System (RWDS) that enables rapid software-based waveform design, development and implementation. RWDS increases designer productivity, supporting real-time functional verification, performance characterization and system analysis. Conventional SDR development platforms are centered around a combination of DSP, GPP and FPGA employing separate tools for individual system components resulting in a disjoint development flow. This requires early allocation of design resources making repartitioning time consuming and costly. The development platforms are often customized for a particular application and do not easily scale to diverse SDR applications. The RWDS is based on a massively parallel processor technology and provides a unified development environment seamlessly spanning algorithm design to final system implementation. It allows for dynamic allocation of processing resources between multiple waveforms as needed. The modularity provides an easy way to configure the system for any SDR application and a path to final form factor by preserving the software stack. Other benefits include model-based design support and library driven module reuse to shorten development time. The RWDS is currently in use for waveform development addressing multiple application segments including mobile radio, military communication, first responder and satellite navigation systems. We present the use of RWDS in the context of a reference radio waveform implementation the details of which are given in terms of a functional decomposition of the system design, mapping to hardware modules and real-time performance characterization.

Describing Radio Hardware and Software Using OWL for Over-The-Air Software Download
Lubomir Stanchev; Todor Cooklev; David Clendenen (Indiana University Purdue University Fort Wayne, USA)

Recently several researchers have discovered the need for radios to use description techniques. Previously described techniques describe information such as the current frequency band, waveform, etc. This paper extends previous work on description techniques. These previous description techniques do not describe waveforms at a level sufficient to determine software/hardware compatibility for over-the-air software download. For example, a device should not attempt to download a wideband waveform if its radio front-end is only narrowband, of if its baseband hardware cannot provide the required MIPS for the new waveform. Over-the-air software download is one of the most interesting features of software-defined radios. The compatibility between software and hardware prior to software download previously had to be verified manually. The approach described here removes the need for man-in-the-loop. It appears that OWL is particularly well suited for such descriptions. We use OWL and discuss its suitability. Examples are presented illustrating the developed technique. The developed ontology and the examples have been developed using the Protégé tool.

Computer Generation of Platform-Adapted Physical Layer Software
Yevgen Voronenko; Volodymyr Arbatov; Christian R Berger; Markus Pueschel; Franz Franchetti (Carnegie Mellon University, USA); Ronghui Peng (University of Utah, USA)

In this paper, we describe a program generator for physical layer (PHY) baseband processing in a software-defined radio implementation. The input of the generator is a very high-level platform-independent description of the transmitter and receiver PHY functionality, represented in a domain-specific declarative language called Operator Language (OL). The output is performance-optimized and platform-tuned C code with single-instruction multiple-data (SIMD) vector intrinsics and threading directives. The generator performs these optimizations by restructuring the algorithms for the individual components at the OL level before mapping to code. This way known compiler limitation are overcome. Further platform tuning is achieved by a feedback-directed search that determines the fastest solution among a space of candidates. We demonstrate the approach and the excellent performance of the generated code on on the IEEE 802.11a (WiFi) receiver and transmitter for all transmission modes.

Resource Management with Real-Time Complexity Monitoring in Software-Defined Radios
Joseph D. Gaeddert; Jeffrey Reed (Virginia Tech, USA)

Software-defined radios (SDR) are typically realized as the deployment of modular digital signal processing blocks on a variety of platforms and promise significant enhancements over traditional radio designs in terms of component re-use and design scalability. Despite their apparent benefits, however, software-defined radios tend to consume more power and provide less throughput than their hardware counterparts (e.g. application-specific integrated circuits and field programmable gate arrays). As a result, SDR platforms have struggled to compete with many legacy systems, particularly as the demand for data throughput on wireless infrastructure increases. This significant performance gap can be mitigated, however, by exploiting the reconfigurable nature of software itself and by compensating for opportunistic channel conditions by pruning unnecessary processing. As shown in [1], [2], real-time power monitoring can be accomplished by modeling processing load for streaming multi-media systems. Furthermore, [3] demonstrated a significant resource reduction by selectively reducing processing to meet a specific target service quality. Our previous work demonstrated that the receiver could significantly reduce its computational complexity while maintaining an equivalent error probability in Rayleigh fading channels simply by choosing a more strategic modulation-/coding-scheme pair at only a slight degradation to its spectral efficiency [4]. This paper extends our previous work by formalizing computational complexity as an analytical model for monitoring the processing load in digital hardware. This model is used to adapt link-level parameters on reconfigurable software radio platforms where processing bandwidth is a discerning factor for data throughput. Furthermore, the results are extended by incorporating additional physical-layer considerations into the analysis. Finally, the system is validated through the assessment of real-time software simulation as well as over-the-air reconfiguration in a controlled wireless environment. [1] C.-H. Lien, Y.-W. Bai, and M.-B. Lin, "Estimation by Software for the Power Consumption of Streaming-Media Servers," IEEE Transactions of Instrumentation and Measurements, vol. 56, no. 5, pp. 1859–1870, October 2007. [2] Y. Hu, Q. Li, and C.-C. J. Kuo, "Run-time Power Consumption Modeling for Embedded Multimedia Systems," in Proceedings of the 11th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, 2005. [3] S. M. Yardi, M. S. Hsiao, T. L. Martin, and D. S. Ha, "Quality-Driven Proactive Computation Elimination for Power-Aware Multimedia Processing," Proceedings of the Design, Automation and Test in Europe Conference and Exhibition, 2005. [4] J. D. Gaeddert and J. H. Reed, "Leveraging Flexibility in Reconfigurable Baseband Processors for Resource Management in Software-Defined and Cognitive Radios," in Software-Defined Radio Forum, December 2009.

Component-based Waveform Development: the Nucleus Tool Flow for Efficient and Portable SDR
Jeronimo Castrillon; Stefan Schürmans; Anastasia Stulova; Weihua Sheng; Torsten Kempf; Aamir Ishaque; Rainer Leupers; Gerd H. Ascheid; Heinrich Meyr (RWTH Aachen University, Germany)

Component-based software engineering (CBSE) is an attractive solution for describing baseband processing applications. It abstracts waveforms in the traditional way algorithm designers envision their applications and guarantees a high degree of portability. However, existing CBSE approaches for SDR have not been able to close the gap between specification and implementation so as to achieve the computational performance and the energy efficiency of handcrafted solutions. Providing a methodology that closes this gap in an efficient way has been the focus of the Nucleus concept as reported in previous publications. This paper presents a tool flow that follows the Nucleus concept, and thus allows for efficient component-based SDR development.

Workshop 5D: Analysts (available presentations)

Workshop 5E: SDR in Space 1 (available presentations)

Expert Lecture 5F: GNU Radio: Introduction and Computational Capabilities (presentation)
Thomas Rondeau, Ph.D.

Session 5G: Processors (available papers and presentations)

A Study on the Hardware Reconfiguration Schemes and their Applications on SDR-based Mobil
Bong-Guk Yu; Kyutae Lim (Georgia Institute of Technology, USA); Sangchul Oh; Hong-Soog Kim (ETRI, Korea)

Recently, mobile communication systems have been recommended to support several frequency bandwidth profiles according to the required user bandwidth in various radio environments. Upcoming fourth-generation mobile systems based on OFDM (Orthogonal Frequency Division Multiplexing) technology have a range of system bandwidth profiles. In view of the implementation issues, a base station with conventional hardware architecture consisting of a RF (Radio Frequency) part, an IF (Intermediate Frequency) part and a baseband modem part is not sufficiently flexible to accommodate several bandwidth profiles efficiently. Therefore, a software radio architecture that can flexibly adopt the various system profiles is needed for the future mobile communication base station. SDR (Software Defined Radio) technology is a promising feature that make possible to accommodate several standards through software changes on a single hardware platform for next-generation mobile communication systems. These advantages have led many research institutes to proceed with commercialization of software radio technology worldwide. This paper presents reconfiguration schemes and their applications on SDR-based mobile communication systems that are reconfigurable to multiple wireless access standards.

Full-reconfigurable interleaver Architecture for High-performance SDR applications
Renaud Pacalet; Jair Gonzalez (Telecom Paristech, France)

Interleaving processing is heavily used in several steps during the communications process. The interleaving method changes drastically among standards, even in some standards there are different interleaving approaches to be applied. For SDR applications, it is necessary to define a reconfigurable interleaver architecture that meets the performance requirements, not only in terms of speed, but also in terms of size, power consumption, and flexibility. This paper presents interleaver/deinterleaver architecture that meets all this requirements and which offers flexibility to implement practically any interleaving method. This architecture allows for running different interleaving process concurrently, either of the same method or different, enabling high performance MIMO applications with the same hardware. This architecture integrates the Interleaving process together with Rate Matching and Frame Equalization, increasing the overall system performance. While the reconfigurable interleaver module can be shared in all the steps of the communications process, because of performance implications it might not be the case for the channel coding/decoding module. This paper also discuss the implementation of two highly optimized interleaver architectures for the specific requirements of turbo coding modules of LTE and UMTS standards.

Leveraging Embedded Heterogeneous Processors for Software Defined Radio Applications
Almohanad Fayez; Qinqin Chen; Jeannette Nounagnon; Charles Bostian (Virginia Tech, USA)

The paper focuses on utilizing embedded processors with integrated General Purpose Processors (GPP) and Digital Signal Processor (DSP) cores for SDR applications. With such processors, developers can leverage running Operating Systems on GPP cores and use DSP cores to accelerate signal processing tasks in building small form factor SDR solutions. The work presented in this paper was done on the Beagleboard platform, a TI OMAP3 processor based platform as a computational platform and a Universal Software Radio Peripheral (USRP) as the software radio front-end. The paper will discuss the toolset support for GPP/DSP based processors and compare the performance for SDR based applications for GPP versus mixed GPP/DSP solutions. The paper also discusses how the OMAP processor can be used to add DSP support for SDR developments tools, specifically GNU Radio.

Multi-Ghz Software and Hardware Platform for Software Defined Radio
Chen Chang (BEEcube Inc., USA)

Developed out of the Berkeley Wireless Research Center (BWRC) at University of California at Berkeley, the BEE3's high-speed multiple FPGA based platform allows for flexible algorithm and feature set definitions to fit mission critical needs. The BEE3 excels as a true real-time development and deployment platform for: • Software Defined Radio (SDR) • Signal Intelligence • Wireless (digital based RF) Algorithm Applications As a result, the BEE3 has attracted leading industry companies worldwide such as Aerospace Corporation, L3 Communications, and Thales Group. BEEcube's SDR Demonstration Our demonstration highlights BEE3 as an SDR prototyping platform - showing off our FPGA based continuous wideband vector signal generator, controlled by software in real-time via Wind River's VxWorks over Gigabit Ethernet, with carrier frequency tone sweeps ranging from 0 to 2GHz. BEE3's inherit I/Q 2Gsps DAC highlights BEE3's wideband capability. The BEE3 ADC expansion board simultaneously captured analog output with Data being displayed directly and integrated with Matlab(tm). BEE3's ADC can sample up to 3 GHz, offering a true direct RF sampling capability. BEE3 Easy Algorithm Deployment Coupled with high-speed I/O and infrastructure, the BEE3 system software allows algorithm designers without any RTL or implementation knowledge to easily program the target BEE3 system.

Session 6A: Applications (available papers and presentations)

Implementation and Evaluation of Distributed Control and Data Channel Coordination Algor
Onur Altintas; Mitsuhiro Nishibori; Rama K Vuyyuru (Toyota Info Technology Center, USA, USA); Youhei Fujii; Kota Nishida; Yuji Oie; Kazuya Tsukamoto; Masato Tsuru (Kyushu Institute of Technology, Japan); Abdulrahman Al-Abbasi; Takeo Fujii (The University of Electro-Communications, Japan); Srikanth Pagadarai; Alexander M. Wyglinski (Worcester Polytechnic Institute, USA)

Dynamic spectrum access techniques are expected to play a vital role in future vehicular communications systems. In this paper we present a cyber-physical proof-of-concept lab implementation of our previously developed control and data channel assignment schemes for vehicle-to-vehicle communications. Specifically, vehicles coordinate data channels after agreeing on a virtual control channel on which they share relevant spectrum and position information. Both control channel(s) and data channels are determined in a distributed fashion. Our implementation is an integration of spectrum sensing and distributed channel coordination functions working on GNU Radio/USRP platform and simulation of primary user "appearances" based on probabilistic event generation.

Sphere Detector for 802.16E Broadband Wireless Systems Implementation on FPGAs
Juanjo Noguera (Xilinx, Inc., Ireland); Stephen Neuendorffer; Sven Van Haastregt; Kees Vissers; Chris Dick (Xilinx, USA); Jesús Barba (University of Castilla-La Mancha, Spain)

Spatial multiplexing for multiple-input-multiple-output (MIMO) communication systems is a computationally intensive wireless application that implements highly demanding digital signal processing algorithms. Sphere decoding (SD) is a complexity-efficient method to solve the MIMO detection problem, while maintaining a bit-error rate (BER) performance comparable to the optimal maximum-likelihood (ML) detection algorithm. However, even this reduced-complexity algorithm is generally not feasible to implement on a DSP processor in real-time. Modern Field Programmable Gate Arrays (FPGAs) are a promising target platform for the implementation of the Sphere Decoder algorithm. Modern FPGAs are programmable high-performance parallel computing platforms that provide programmability with the performance efficiency of dedicated hardware solutions (i.e., ASICs). However, the key barrier for the widespread adoption of FPGAs in baseband wireless algorithms is the traditional hardware-centric design-flow and tools. That is, the use of FPGAs requires significant hardware design experience, as for example, being familiar in writing RTL HDL (hardware description language) code, which typically requires a longer development time and is more error prone than implementing the application using a high-level programming language (e.g., C/C++) targeting a DSP processor.

Software Defined Implementation of MPEG4 decoder on Sandblaster SB3500 DSP (Best of R&D)
Vaidyanathan Ramadurai; Daniel S Iancu (Optimum Semiconductor Technologies, USA); Mayan Moudgill; Gary Nacer; John Glossner (Sandbridge Technologies, USA)

MPEG4 decoder is predominantly used in video broadcast applications, mobile communications, surveillance and security, and multimedia streaming over the internet. Multimedia signal processing algorithms in MPEG4 and H.264 video codecs are characterized by high computational complexity and high memory bandwidth requirements. The decoder uses temporal, spatial and variable length decoding to reconstruct the original frames from the compressed video. The temporal decoding is based on motion compensation which is block based. The block sizes can be 16x16 or 8x8 with half pixel resolutions. Spatial decoding is done using an 8x8 IDCT. Huffman and run-length codes are used in variable length decoding. In addition, MPEG4 also provides various prediction modes for both temporally and spatially coded frames. An MPEG4 simple profile decoder is implemented on Sandblaster SB3500 for high resolutions like VGA (640x480) and D1 (720x480). The Sandblaster SB3500 is a compact and power-efficient system-on-chip platform tailored for wireless and multimedia devices. The SB3500 provides a high level of parallelism at the instruction level and at the data level. Additionally the SB3500 employs simultaneous execution of 12 threads thereby allowing real time tasks to run in parallel. Multiple levels of parallelism has been exploited to implement an efficient high resolution MPEG4 decoder. The SB3500 also has facility for block DMAs (Direct Memory Access) as well as scatter/gather DMAs. The DMAs provide efficient movement of high bandwidth data like video reference frames from external memory to local memory. We provide a brief overview of the architecture of SB3500. After an introduction on MPEG4 simple profile decoder, we provide the details of the software defined implementation of the decoder on SB3500 with focus on optimizations of key video kernels for compute and memory. The entire software is implemented in C without any hardware acceleration. The decoder has been optimized to utilize less than 9% of the total DSP signal processing capacity. We also compare our implementation on SB3500 to a similar implementation on SB3011. The SB3500 provides approximately 6 times better throughput performance, thereby providing the scalability to higher resolutions like 720p and 1080i HD (High Definition).

Dynamically Reconfigurable Software Defined Radio for GNSS Applications
Alison Brown (NAVSYS Corporatiaon, USA)

Historically, the military has used special purpose Global Positioning System (GPS) radios for radio navigation. This has the disadvantage of locking users into block technology designed to meet a fixed set of requirements. NAVSYS Corporation and other companies have been developing software GPS receivers that have the advantage of being able to easily adapt to the signal processing algorithms for future GPS signals without changing or modifying the hardware of the GPS receiver. Continued improvements in SDR technology are enabling their use for Global Navigation Satellite Systems (GNSS) applications that require small form factor, low-power designs. NAVSYS Corporation is currently leveraging our prior GPS SDR development efforts to design a miniaturized SDR architecture with low-power design features and dynamic reconfiguration of the receiver channels to allow different GNSS frequency bands and signal codes to be processed by each channel. The SDR design being developed is flexible enough to cover the GNSS frequency bands for L1 and L2 operation and the new civil L5 frequencies using either the military or civil codes. The design is flexible enough to handle in the future the signals from other GNSS satellite systems such as Galileo or GLONASS. The design will result in a small form factor design which is suitable for use in handheld and micro air vehicle applications.

Session 6B: System Implementation and Test III (available papers and presentations)

Labview Channel Estimator
Fanny Mlinarsky; Samuel MacMullan (ORB Analytics, USA)

Fox is a software based channel emulator that models a wireless channel with up to 4x4 MIMO paths. While currently supporting 802.11n channel models, Fox can be extended to incorporate other channel models, including LTE and a variety of military or proprietary models. Fox operates in the LabVIEW environment and works on MIMO streams of IQ samples. The demo will show operation on IQ streams stored in files and will include a presentation explaining the background and theory of wireless channel modeling. We will overview the industry standard channel models, including 802.11n, ITU (pedestrian and vehicular), LTE, LTE-Advanced, 802.11ac, 802.11ad channel models. We will explain and demonstrate the statistical nature of channel models.

Real-Time, Software-Based Characterization of Receiver Dynamic Channel Performance
Brian A. Dalio; Ivan Aguayo (Coherent Logix, Inc., USA)

We present the design and implementation of a real-time, software-based analysis and characterization environment for evaluating the performance of software defined radio (SDR) receivers in the presence of dynamic channel conditions as well as additive white Gaussian noise (AWGN). Various conventional analysis and characterization environments emphasize different points along the dimensions of complexity / controlability of the channel conditions, observability of the receiver's processing, and accumulation rate of results. In general, the more realistic the channel modeling, the more observable the receiver's processing, and the earlier in the design process, the lower the accumulation rate of results. Accumulating the data to accurately determine the BER / PER performance of a receiver during the design exploration phase can require a farm of simulation servers and years of CPU time. Our characterization and analysis environment supports the characterization of a software model of the receiver in real-time. Test parameters (e.g., SNR, multi-path model parameters, packet size) are sent to the development platform. Separate long-period (2^258 x 64-bit) URNGs are used to ensure uniqueness of test messages and channel conditions. Messages are automatically generated, transmitted through a dynamic channel emulator, and presented to the receiver. The decoded results are compared to the original message and relevant statistics collected. All operations are under the control of an interactive host system program. Since the system runs in real-time, results can be accumulated as fast as the waveform can operate. Hundreds to thousands of test results per second can be accumulated. Multiple development platforms may be run in parallel to further increase this rate. The environment has been implemented on a software-based integrated radio waveform development system and used to characterize the performance of multiple receiver configurations. We present details of these characterizations, system performance, and overall resource usage. We present the design and implementation of a real-time, software-based analysis and characterization environment for evaluating the performance of software defined radio (SDR) receivers in the presence of dynamic channel conditions as well as additive white Gaussian noise (AWGN). Various conventional analysis and characterization environments emphasize different points along the dimensions of complexity / controlability of the channel conditions, observability of the receiver's processing, and accumulation rate of results. In general, the more realistic the channel modeling, the more observable the receiver's processing, and the earlier in the design process, the lower the accumulation rate of results. Accumulating the data to accurately determine the BER / PER performance of a receiver during the design exploration phase can require a farm of simulation servers and years of CPU time. Our characterization and analysis environment supports the characterization of a software model of the receiver in real-time. Test parameters (e.g., SNR, multi-path model parameters, packet size) are sent to the development platform. Separate long-period RNGs are used to ensure uniqueness of test messages and channel conditions. Messages are automatically generated, transmitted through a dynamic channel emulator, and presented to the receiver. The decoded results are compared to the original message and relevant statistics collected. All operations are under the control of an interactive host system program. Since the system runs in real-time, results can be accumulated as fast as the waveform can operate. Hundreds to thousands of test results per second can be accumulated. Multiple development platforms may be run in parallel to further increase this rate. The environment has been implemented on a software-based integrated radio waveform development system and used to characterize the performance of multiple receiver configurations. We present details of these characterizations, system performance, and overall resource usage.

Port Testing in a Dual-Star Network: Embedded LANs for RF
Steven Groves (Harris, USA)

Port Testing in a Dual-Star Network: Embedded LANs for RF. In today's RF base stations, it is not unusual for a design to contain several microprocessors and/or DSPs, which need to talk to each other within a closed chassis, probably via an embedded LAN. In Harris's MASTR V public service base station, for example, the chassis is divided into removable modules, each with one or more CPUs and DSPs, whether the module is a receiver, a transmitter, a controller, etc, and they connect with each other on an embedded LAN. In critical applications, like public service, a wise approach to embedded LAN design would be to have two switches in a chassis, with each switch independently connected to all the modules in the chassis. That way, either switch can provide for the LAN in case the other switch is either down or has a connection failure to any module. This effectively creates two switches connected in a parallel "dual star" configuration. This is MASTR V's design. The dual star network then requires a software task: have exactly one active switch in operation at a time to avoid packet redundancies, and to change switches immediately if the active switch has issues. This would require all modules and both switches to always test the connection points, and ensure test information is transferred to both switches. Hence, a "packet forwarding" technique is developed for the dual-star embedded LAN as described in this article.

On The Use of Scrubbing for SEU Mitigation
Rainer Storn (Rohde & Schwarz GmbH & Co. KG, Germany)

Today's SDRs make heavy use of GPPs, DSP, and FPGAs in order to handle the high processing load incurred by the reconfigurable part of the radio. As radios and waveforms become ever more complex the memory requirement reaches the orders of many Megabytes. In airborne environments such memory demands constitute a problem since especially at high altitudes, e.g. 60,000 ft there exists the problem of single event upset (SEU). These SEUs are caused by energetic neutrons hitting the surface of silicon devices leading to transient errors due to bit flips. Although there exist processors and FPGAs that are radiation hardened there is a great tendency to use COTS devices in order to save device costs. If COTS devices are used some kind of redundancy must compensate for their SEU susceptibility. Ideally this redundancy is SW based so that it can potentially be applied to a large variety of processor devices. In this paper a new technique calle fast scrubbing is introduced to mitigate the SEU problem for DSPs and GPPs.

Session 6C: Networks (available papers and presentations)

Testing Multi-Services Mobile Adhoc Networks Effectively
Sherin Kamal; JD. Aishman (Science Applications International Corp.(SAIC), USA)

This paper's arguments start and end with the belief that "simple is easy to envision, but hard to implement". The literature is packed with emerging network architectures that propose mobile platforms (ground or airborne) move freely with little or no hierarchy to execute their missions. This is notable in the defense literature and in emergency response or disaster relief applications. Here single points of failures and fragmented connectivity can cripple networks that are too structured. The underlying premise in mobile adhoc networks (MANETs) is that connectivity is maintained despite routing paths varying due to radios being mobile and radio (RF) links being unstable. Despite such challenges, timely information and situational awareness are critical to allowing such forces to either achieve battlefield superiority or overcome emergency/disaster situations with lower losses and/or fewer assets deployed. The paper addresses the realities of how the availability of development and test environments are often out of sync with the increasingly complex software that is being embedded in modern military and security communications devices. Ultimately, the paper's intent is to propose processes and disciplines by which netcentric products in MANETs should be tested differently than radios are today.

Software Defined Radio Based Wireless Grids
Xuetao Chen; S M Hasan; Tamal Bose; Jeffrey Reed (Virginia Tech, USA)

Wireless grids can group different types of resources and share them within the grids through the wireless links. The resource could be attached to the heterogeneous devices, such as mobile smart phones, laptops, and even some dummy devices like sensor, printers and cameras. To share the resources, those devices needs to communicate with each other through the wireless links. Because those devices may have different wireless links, the reconfiguration of PHY/MAC layers is needed to maintain a ubiquitous connection. The reconfiguration of SDR enables the wireless grids to connect different types of mobile platforms. In addition, the resource sharing within a grid is inherently a wireless distributed system. Depending on the applications, the specifications of resource sharing may vary. For example, the synchronizations and the timing schemes for sensors sharing and CPU sharing are different from each other. These differences also require the reconfiguration of higher layer protocol in addition to PHY/MAC. In this paper we will firstly introduce the structure of the wireless grids based on SDR. Then we will discuss the challenges for designing the SDR-based wireless grids, which includes RF reconfiguration and synchronization schemes. An example is given at the end of the paper to verify the proposed concepts and illustrate the possible applications.

Fundamental Issues of Wireless Distributed Computing in SDR Networks (Best of R&D Track)
Dinesh Datla; S M Hasan; Jeffrey Reed; Tamal Bose (Virginia Tech, USA)

Software defined radio (SDR) applications in tactical radio networks involve complex computational processing with stringent hardware and quality-of-service (QoS) constraints. Individual nodes in a network may not meet the high service QoS requirements and may not be able to execute complex tasks by themselves due to resource constraints and limited functionality. In such scenarios, it can be advantageous to execute computational tasks in collaboration with peer nodes by wireless distributed computing (WDC). Such an approach potentially offers several benefits such as efficient resource utilization, robustness and security. However, it is bound to impose an additional communication cost. It is important to understand the scalability and fundamental limitations imposed by the underlying communication system on WDC before pursuing further research on developing architectures, protocols and algorithms for distributed computing in collaborative SDR networks. This paper analyzes the conditions under which WDC is energy efficient as compared to local on-board processing of computational tasks. In addition, the paper discusses the effect of channel errors on the accuracy of the distributed processing.

Design challenges for robust ground-to-ground waveforms for tactical software-defined radio
Sebastian Hanigk (Universität der Bundeswehr München, Germany)

With the advent of software-defined radio devices, mobile ad-hoc networks have gained additional capabilities due to the ease of reconfiguration of the air interface and protocol stack. While work in the area of car-to-car networks and user mobility often focuses on the effectiveness and efficiency of a certain protocol stack, software-defined radio devices offer the possibility of switching between protocols, frequencies and medium access and medium division mechanisms. In this paper, we give a comprehensive study on design challenges for robust tactical ad-hoc networking waveforms.

Design of Modular SDR Architecture for Resource Constrained MANET
Dhadesugoor R. Vaman; Swapna Raj (Prairie View A&M University, USA); Raghavan Muralidharan (Tata Power SED, India)

A design and implementation of SDR for Mobile Ad Hoc Network with different dynamically configurable functions in order to achieve the desired QoS for multi-service applications and handle different radio impairments to provide a seamless information transport across radio units. The design (for MANET & sensor networks) encompasses: • Multi-Function/Multi-Frequency Radio and Sensor Capability in a Tactical Environment (Dynamic Re-configurability) • Multi-hop Capability with Power/Energy Efficient Routing to Maintain Desired QoS for Each Application • Design of Efficient (Power and Bandwidth) Management Function in Each Radio • Minimal Disruption in Communications for High Priority Applications • Efficient Use of Available Spectrum (Cognitive Radio) • Maintain Communications even Under Multi-path Fading Interference with Variability of Information Transfer Rate An initial implementation of the SDR design is presented in terms of dynamical changes to the modulation methods, cognitive radio function and dynamical changes to the effective data rate to sustain bounded performance in terms of sustained data rate, response time and data error rate which are the basic performance measures to support QoS.

Policy-based energy efficient data report method for multi-mode wireless sensor networks
Kosuke Yamazaki; Issei Kanno; Yuji Ikeda; Hiroyasu Ishikawa (KDDI R&D Laboratories Inc., Japan)

A great advantage of the software defined radio (SDR) technique is that multiple radio access systems can be installed on the simple hardware. This feature becomes even more important, especially when SDR is applied into embedded and power-critical systems, e.g. machine-to-machine networks or embedded sensor networks. There, hardware cost should be minimized and complete hardware replacement to add or update radio access system is very difficult. The wireless sensor network (WSN) is a typical application of an embedded system. WSN consists of a huge amount of sensor nodes with very limited resources. They are usually located in untouchable areas, e.g. on street lights , in a desert island, in deep sea and the number of deployed sensor nodes tends to be huge volume. Therefore, radio access system changes generate huge costs. The SDR technique can reduce these costs dramatically, moreover, allow sensor node to use multiple radio access systems with even simple hardware.

Workshop 6D: Analysts (available presentations)

Workshop 6E: SDR in Space II (available presentations)

3 December 2010

Session 7A: Waveform and Software Design II (available papers and presentations)

Complexity Analysis of Software Defined DVB-T2 Physical Layer
Stefan Grönroos (Åbo Akademi University, Finland); Kristian Nybom (Åbo Akademi University, Finland); Jerker Björkqvist (Åbo Akademi University, Finland)

The second generation terrestrial TV broadcasting standard from the Digital Video Broadcasting (DVB) project, DVB-T2, has recently been standardized. In this paper we will perform a complexity analysis of our GNU Radio based implementation of the modulator/demodulator parts of a DVB-T2 transmitter and receiver. First we describe the various stages of a T2 modulator and demodulator, as well as how they have been implemented in our system. We then perform an analysis of the computational complexity of each signal processing block. The complexity analysis is performed in order to identify the blocks that are not feasible to run in real-time on a general purpose processor. Furthermore, we discuss possibilities of implementing these computationally heavy blocks on GPUs (Graphics Processing Units), FPGAs (Field-Programmable Gate Arrays), and other architectures that would still allow them to be implemented in software and thus be easily reconfigurable. A software defined implementation of DVB-T2 will, for instance, be quite useful in the development of the next generation mobile TV standard DVB-NGH (Next Generation Handheld). DVB-NGH will most likely be based on DVB-T2, but is expected to introduce some changes throughout the system.

A Lightweight Dataflow Approach for Design and Implementation of SDR Systems
Chung-Ching Shen; William Plishker; Hsiang-Huang Wu; Shuvra Bhattacharyya (University of Maryland, USA)

Model-based design methods based on dataflow models of computation are attractive for design and implementation of wireless communication systems because of their intuitive correspondence to communication system block diagrams, and the formal structure that is exposed through formal dataflow representations (e.g., see [1]). Dataflow modeling is used in important commercial tools that support design and implementation of wireless communication systems, such as LabVIEW by National Instruments, and ADS by Agilent Technologies. In this paper, we introduce a lightweight dataflow programming model for model-based design and implementation of wireless communication and software-defined radio systems.

Rapid Prototyping of Communication Waveforms from a High-level Design Language
Mark Beardslee; Matt Hall; Zhong Shang (Coherent Logix, Inc., USA)

This paper presents a rapid prototyping system for realizing communication waveforms onto a real-time multi-processor hardware platform which runs a standard programming language such as ANSI C. The waveform is described in a high-level design language, such as The Mathwork's Simulink, and is transformed to an executable multi-processor program using C-code generation tools from The Mathworks and a software tool flow called the HyperX Integrated System Development Environment (HxISDE). The transformation is done automatically guided by user constraints on the performance of the resulting real-time design. The constraints come from two sources: user constraints such as design latency, throughput, and the number of available processors, and platform derived constraints such as processor speed, and instruction and data storage limits. While respecting these constraints, the transformation algorithm first characterizes the basic executable units from the user's design and then allocates them onto processors while also taking into account the cost of data communication between processors. The verification tests from the user's high-level design environment are employed to verify the resulting C-code implementation using both the HxISDE's cycle accurate simulator and by running the design on the real-time hardware system. Using this tool flow and transformation procedure, the user can rapidly create a verified C-code design which runs in real-time on a multi-processor platform. In this paper we present the details of the transformation process and demonstrate its operation on some commonly used communication waveforms.

Interference Alignment Using NI FlexRIO
N. Prasanth Anthapadmanabhan (Bell Labs, Alcatel-Lucent, USA); J. Saul Duran; Kyle Miller; Vidur Bhargava; Sriram Vishwanath (University of Texas at Austin, USA); Takao Inoue; Ahsan Aziz (National Instruments, USA)

Interference Alignment (IA) is a fresh and exciting interference management technique for wireless networks. IA promises a linear increase in throughput with the number of users in a wireless system, and is known to be capacity optimal for classes of wireless networks. The current promise of IA is in theory, with limited practical literature in existence to verify these claims. This paper represents one of the first efforts to understand the true potential of interference alignment in practical wireless systems.

Interfacing a Reasoner with an SDR Using a Thin, Generic API: A GNU Radio Example
Jakub Moskal; Mieczyslaw Kokar; Shujun Li (Northeastern University, USA)

Developing the Cognitive Radio (CR) architecture on top of a SDR platform requires two features: 1) access to the radio's contextual information (meters) that comes from its self-awareness and from sensing its environment, and 2) the ability to alter the radio's operational behavior by modifying its parameters (knobs). Since different SDRs offer different ways to access their knobs and meters, it is a challenge to design a CR architecture that would work with all or at least with most of the radio platforms. A common solution to the problem of interfacing multiple software components is to introduce a public API. This allows the developers to implement just one API and enable their software to interface with many components, developed independently. To ensure the quality of the API and to attract the majority of a community, APIs are standardized by organizations, rather than single companies.

Session 7B: RF, IF, ADC (papers) (presentations)

Wideband Transceivers for Software Radio: A space segment survey
Fabrizio Massaro (LuxSpace Sárl, Luxemburg); Jens P. Elsner (Karlsruhe Institute of Technology (KIT), Germany); Florio Dalla Vedova (LuxSpace Sárl, Luxemburg); Friedrich K. Jondral (Karlsruhe Institute of Technology, Germany)

The life time of satellites exceeds the development cycles of today's wireless protocols. This fact is a driver for the increasing interest in software radio for space applications. Two major technical design obstacles stand in the way: strict power and weight constraints on the one hand, and availability of space certified components on the other hand. This paper surveys and evaluates currently available space certified components for use in software defined radio receivers. Introduction Optimizing the use of in-orbit resources is one of the means for the operators to protect and develop their market assets in new area of services, types of applications.

Multi-Radio Coexistence and Collaboration on an SDR Platform (Best of R&D Track)
Tommi Zetterman; Antti Piipponen; Kalle Raiskila; Sverre Slotte (Nokia Research Center, Finland)

The growing number of wireless standards together with the trend of using multiple simultaneously active radios in handsets bring new challenges and possibilities for multi-radio capable Software Defined Radio (SDR) platform design. Especially, future cognitive radios that exploit the spectrum holes left unused or underused by primary radios benefit from an agile SDR platform that allows radios to dynamically react and adapt their behavior to the quickly changing operating conditions and the varying combination of other available radios. We define for our platform a holistic multi-radio control framework, which enables independently developed radios to coexist and collaborate in hardware and spectrum resource sharing. Further, our framework makes it easier to bring cognitive features like spectrum usage agility to legacy, non-cognitive radio protocols. We present our multi-radio control framework, which is part of the radio operating system running on the SDR hardware platform. The framework consists of two main parts: 1) MRC for dynamic scheduling, and 2) co-operative Resource Manager (RM) for semi-dynamic control.

Antenna Design Strategy and Demonstration for Software-Defined Radio (Best of R&D Trac
Taeyoung Yang; William Davis; Warren Stutzman; S M Hasan; Randall Nealy; Carl B. Dietrich; Jeffrey Reed (Virginia Tech, USA)

Software-defined radios offer opportunities for a variety of applications in consumer electronics, public safety, and military. However, there are practical design issues because of the required wide operating frequency range from HF to C-band and beyond. The required wide bandwidth should be considered in analog functions (antennas and RF frontends), digital operations (baseband and software), and transition domains (ADC/DAC) during the implementation of a software-defined radio. It is very challenging to design a simple, rugged, highly-efficient broadband antenna with compact size. Achieving ideal performance is limited by radiation physics, not technology. Therefore, an important key to successfully developing high-performance, electrically-small antennas is to understand antenna radiation physics and apply the associated physical-limit constraints (fundamental limit theory) from the start of the system design process. In this paper, we review the fundamental theories that limit antenna size and performance, including operational bandwidth, gain, radiation pattern, and range.

Bringing RF Tunability to Mobile Communications Markets
Peter Bacon (Peregrine Semiconductor, USA)

Peregrine Semiconductor's UltraCMOS® technology has demonstrated superior RF performance in comparison to other Silicon and SOI based processes. Utilizing this advanced silicon on sapphire technology provides an unprecedented level of RF performance while supporting analog and digital integration that CMOS is known for. Over the past decade UltraCMOS has penetrated the commercial handset market and is now known as the technology of choice to address the linearity, power, performance, and ever increasing integration requirements of the cellular RF front end. New developments at Peregrine Semiconductor continue to focus on leveraging the performance and integration capability of the UltraCMOS technology more extensively throughout the front end to bring frequency and operational mode agility to the commonly discrete channel implementations of today's smart 3G and 4G phones. This paper will discuss fundamental RF tuning techniques made possible with UltraCMOS that support antenna impedance and frequency tuning, power amplifier multi-mode operation, and power control implementations.

A High Performance RF Transceiver Implementation
Neil Dodson; Glenn Bradford; J. Nicholas Laneman (University of Notre Dame, USA)

One key goal of software-defined radio (SDR) is to provide the possibility of operating in a wide range of frequency bands with one single device. At the same time, real-world communication systems require a high degree of amplification and filtering to achieve acceptable performance. Realizing these two goals creates an inherent challenge, as both high frequency selectivity and wide bandwidth tunability are generally difficult to achieve concurrently in a high performance system. This paper details the development of a high performance transceiver radio frequency (RF) daughtercard designed to be used in conjunction with the Ettus Research Universal Software Radio Peripheral (USRP).

Session 7C: Spectrum, Regulatory and Standards (available papers and presentations)

Power Fingerprinting in Unauthorized Software Execution Detection for SDR Regulatory
Carlos Aguayo Gonzalez; Jeffrey Reed (Virginia Tech, USA)

Software-defined radios (SDRs) improve flexibility and reduce development and maintenance costs in modern wireless communication systems. Unfortunately, they also present increased interference risks as a result of their ability to access wide spectral bands and their vulnerability to malicious software attacks. Hence, monitoring execution integrity is a critical element in regulatory policy for SDRs. Power fingerprinting (PF) has been proposed as a technique to assess the integrity of SDRs and detect the execution of unauthorized software. PF obtains execution status information from the dynamic power consumption of the processor and extracts discriminatory features from it to determine whether the execution is authorized. In this paper, we provide further evidence of the ability of PF to detect unauthorized execution in SDR. Our results show that it is feasible to detect an unauthorized change in the configuration of a PICDEM Z evaluation board which doubles the transmission bandwidth using PF.

Ottavio Picchi; Marco Luise (University of Pisa, Italy); Taj Sturman (EADS Astrium Ltd, United Kingdom); Fabrizio Vergari; Emilio Bolzan (Selex - Communications, Italy); Timo Braysy (University of Oulu, Finland); Raúl Dopico López; Julio Diez Ruiz (Indra Sistemas S.A., Spain); Gianmarco Baldini (Joint Research Centre, European Union)

Effective international public safety communications has become in more recent times a principal focal point; partly motivated by the increased risk of concentrated natural disasters, such as flooding, earthquakes and fires, and partly, due to the risks and consequent impact of terrorist attacks. This paper focuses on a European Commission (EC) Seventh Framework Pro- gramme (FP7) initiative known as EULER - European SDR (Software Defined Radio) for wireless in joint security operations. The EULER project seeks to demonstrate the benefits of SDR pertaining to a natural disaster of significant stature such as to solicit a coordinated pan-European response.

Policy-Based Remote Spectrum Coordination
Thaddeus Konicki; Timothy Bieniosek; Harris Zebrowitz (Lockheed Martin Advanced Technology Laboratories, USA); Ritu Chadha; Jason Chiang; William Kline; Constantin Serban (Telcordia Technologies, Inc., USA)

The Policy-Based Spectrum Coordinator (PBSC) that is described in this paper is designed to provide spectrum analysis and assignment for SDS-equipped mobile nodes in military ad-hoc networks. The PBSC system performs the following activities: a) optimizes the spectrum assignment for a number of networks deployed in a given area, taking into account the network operational plan, and allowable frequencies, b) automatically deploys and configures the radios for a given network as a result of such planning, and c) autonomously monitors and reacts to changes in the network and its environment. The implementation of the PBSC is the integration of the Coalition Joint Spectrum Management Planning Tool (CJSMPT) spectrum planner and DRAMA, a policy-based network management system, that together offers policy-based remote spectrum control of SDS networks. CJSMPT provides spectrum management and planning capabilities for efficient spectrum assignment and interference mitigation between Blue Force Systems within an Area of Interest (AOI) and spectrum-dependent devices that are part of an operation that is being planned. DRAMA is a policy-based network management system (PBNMS) that manages dynamic networks using distributed intelligent agents allowing operators to express networking behavior requirements at an abstract level without manual updates. The CJSMPT/DRAMA integrated system provides spectrum-focused policy rule development, management, deployment, and execution along with network node feedback of alarms and location information.

State of the Art in ETSI SDR and CR related Standardization and Preparation of Commer
Markus Muck (Infineon Technologies, Germany); Kari Kalliojarvi (Nokia Research Center, Finland); Jens Gebert (Alcatel-Lucent, Germany); Gianmarco Baldini (Joint Research Centre - European Commission, Italy); Andrea Lorelli (ETSI, France)

This paper will detail the approach and current status of ETSI RRS Standardization in the area of SDR and CR. In particular, the following areas will be addressed: o WG1 focuses on "System Aspects" and develops proposals from a system aspects point of view for a common framework in TC RRS with the aims to guarantee coherence among the different TC RRS WGs and to avoid overlapping and gaps between related activities; WG1 has conducted feasibility studies on Cognitive Radio Systems (CRS) concept and potential regulatory aspects of CRS and SDR. The technical concept of CRS developed by WG1 includes the following key elements: a) Objectives; b) Spectrum use scenarios; c) Technical requirements; d) Spectrum management layers; e) Architectural approaches; f) Enabling technologies. Enhancing user experience is one of the main objectives of the CRS. Application examples are cross-operator access, user networks, flexible access to future internet, and connecting to smart spaces. CRS is expected to be beneficial for optimization of the mobile operator network.

Session 7D: Communications Signal Processing III (available papers and presentations)

LDPC Decoding on the Sandbridge Sandblaster SDR Platform (Best of R&D Track)
Murugappan Senthilvelan; Michael Schulte (University of Wisconsin-Madison, USA); Meng Yu (Sandbridge Technologies Inc., USA); Daniel S Iancu (Optimum Semiconductor Technologies, USA); Mihai Sima (University of Victoria, Canada);

Wireless protocols strive to increase spectral efficiency and achieve high data throughput. Low Density Parity Check (LDPC) codes are advanced Forward Error Correction (FEC) codes that use iterative decoding techniques to achieve Shannon capacity. Because of their superior performance, state-of-art wireless protocols, such as WiMAX and LTE Advanced, are adopting the LDPC codes. LDPC codes come with the high cost of drastically increased computational effort for decoding. LDPC decoding is performed by iterative message passing between "variable" nodes and "parity check" nodes on a bipartite graph. Among the proposed algorithms, the Belief Propagation algorithm leads to a good approximation of an optimal ideal decoder, however, it uses compute-intensive hyperbolic functions. In order to reduce the computational complexity of the decoder, simplified algorithms, such as the min-sum and Lamda-min algorithms, have been proposed. This paper compares fixed-point implementations of these different LDPC decoding algorithms implemented on the low-power multithreaded Sandbridge Sandblaster SB3000 platform against a dual precision floating-point implementation.

Exploiting Cyclic Prefix Redundancy in OFDM to improve decoding of LDPC code
Peter Farkas; Tomas Palenik (Slovak University of Technology, Slovakia)

The redundancy, which is added in transmitter in standard OFDM in form of Cyclic prefix (CP) is usually discarded in receiver. However it can be interpreted as a repetition code, which repeats only part of the symbols and each only once. Therefore it is rather weak error control code. Newer the less the receiver could be modified in order to implement a signal processing technique, which allows to increase error correcting capability of an LDPC code. In our paper the details on this implementation in connection with LDPC codes and results of corresponding simulations are presented.

Bandwidth Efficient Coded Modulation for SDR
Saleh Faruque; Mohit Dhawan (University of North Dakota, USA)

Over the last 20 years,there has been an explosive growth in the wireless industry. With the addition of wireless data services such as e-mail access and Internet browsing, the demand on network resources will continue to rise, leading to network congestion. It has been envisioned that a software defined radio (SDR) is the next generation cellular radio, which will coexist with cellular radios and share the same platform, thereby increasing the capacity, while supporting variable bit rates. This paper presents a coded modulation technique, which combines Forward Error Control Coding (FECC) and a programmable time division modulation in one platform to reduce bandwidth and enhance capacity for broadband networks utilizing SDR. In the proposed scheme, the input high-speed data stream is inverse multiplexed into several parallel streams. These parallel streams, now reduced in speed, are mapped into a Bi-orthogonal codes, stored in a ROM (Read Only Memory). Next, the output of the ROM, which is an orthogonal code, demultiplexed again form a set of parallel stream and then modulated by means of a programmable time divition modulator. This methodology achieves bandwidth efficiency for high speed data communications over wireless networks. The outcome is a coded modulation scheme that detects and corrects bit errors with bandwidth efficiency. The scheme is well suited for SDR to support variable bit rates.

Software Implementation of Near-ML Soft-Output MIMO Detection
Daniele Lo Iacono; Teo Cupaiuolo (STMicroelectronics, Italy)

The continuous emerging of new communication standards is pushing towards the introduction of the Software Defined Radio (SDR) concept. SDR is enabled by performing computational intensive task in software rather than using dedicated hardware. Within the SDR framework, Soft-Output (SO) Multiple-Input Multiple-Output (MIMO) detection is still a major challenge, which only few papers have dealt with so far. In this paper we describe the implementation of the Layered ORthogonal Lattice Detector SO MIMO detector on the programmable Block Processor Engine (BPE). Results show that real-time MIMO detection can be achieved using a cluster of four BPEs running at 350 MHz (65 nm STMicroelectronics CMOS low-power technology) and delivering up to 150 Mbit/s for the 64-QAM modulation, 2x2 antennas configuration.

Reduced Complexity Soft MMSE MIMO Detector Architecture
Kiarash Amiri; Joseph R. Cavallaro (Rice University, USA); Chris Dick; Raghu Rao (Xilinx, USA)

Computing the soft LLR values in MMSE receivers of MIMO systems requires a very large complexity. In this paper, we propose a reduced complexity soft MMSE detector for MIMO systems. We use different complexity reductions techniques and propose an architecture based on the new reduced-complexity method. We also compare the complexity and show more than 2x complexity reduction using this method. Finally, we present the BER performance comparisons using Monte-Carlo simulation.

Expert Lecture 7E: Modem Tutorial (presentation)

Tutorial 7F: ESSOR SDR Architecture – Motivation and Overview (presentation)

Tech Showcase

Sora -- High Performance Software Radio Platform Based on PC Architecture
Jiansong Zhang; Kun Tan; Sen Xiang; Qiufeng Yin; Qi Luo; Yong He; Yongguang Zhang (Microsoft Research Asia, P.R. China); Ji Fang (Beijing Jiaotong University, P.R. China)

This demo shows Sora, a fully programmable software radio platform based on general-purpose processors. With Sora, developers can implement and experiment with high-speed wireless protocol stacks, e.g. IEEE 802.11a/b/g and LTE, on commodity PCs, using familiar programming environments with powerful tools on standard operating systems. In the demo, we first show a Sora-based demonstration radio system, called SoftWiFi. SoftWiFi is a full suite of 802.11a/b/g implementation that can seamlessly interoperate with commercial 802.11 NICs at all modulation rates, and achieves equivalent performance as commercial NICs at each modulation. Then, we show another application that performs spectrum analyzing based on Sora on a normal PC. We demonstrate that with proper software architecture and programming optimization, general purpose processors have sufficient processing power for many wireless processing tasks. We believe such processing power of GPPs will continue increasing with ever falling price driven by Moore's law and large market. Sora is now available for non-commercial use as Microsoft Software Radio Academic Kit.Our final goal is to make Sora a common research platform to the community to facilitate the experimental research in high-speed wide-band cognitive and wireless research.

OSSIE/GNU Radio Generic Component Demonstration
Duyun Chen; Carl B. Dietrich (Virginia Tech, USA); Garrett Vanhoy (University of Arizona, USA); Marypat Beaufait (University of Michigan, USA)

A Generic Component (GC) was created to integrate OSSIE and GNU Radio (GR), two widely used open source development suites for Software Defined Radio (SDR). The GC is an OSSIE component which can encapsulate one or more GR blocks and provide the necessary data conversions to interface OSSIE I/O with the GR blocks. The GCs encapsulated GR blocks and the GR block properties can be reconfigured at runtime. The purpose of this demonstration is to show the functionality of the GC in addition to the distributed waveform capability of OSSIE applied to GR.

LabVIEW Channel Emulator
Fanny Mlinarsky (octoScope, USA); Samuel MacMullan (ORB Analytics, USA)

Fox is a software based channel emulator that models a wireless channel with up to 4x4 MIMO paths. While currently supporting 802.11n channel models, Fox can be extended to incorporate other channel models, including LTE and a variety of military or proprietary models. Fox operates in the LabVIEW environment and works on MIMO streams of IQ samples. The demo will show operation on IQ streams stored in files and will include a presentation explaining the background and theory of wireless channel modeling. We will overview the industry standard channel models, including 802.11n, ITU (pedestrian and vehicular), LTE, LTE-Advanced, 802.11ac, 802.11ad channel models. We will explain and demonstrate the statistical nature of channel models.

Execution Time Monitoring with the ALOE SDR Middleware
Ismael Gomez; Antoni Gelonch; Vuk Marojevic (Polytechnical University of Catalonia, Spain)

Monitoring waveform execution time in Software-Defined Radios is essential in modern multi-processor radios. The process of assigning computing resources to waveform components improves with the accuracy of waveform components resource demands. In shared-resource radio infrastructures, this feature is essential since it provides a mechanism for resource accounting while ensures that a client is unable to block another. Multi-processor platform must ensure, in addition, that data-flows from one processor to another do not violate end-to-end latency constraints. Moreover, modern iterative algorithms (LDPC, turbo-decoding, etc.) consume different resources as a function of the receiver EbNo or target QoS. Therefore, computing resource managers capable to measure resource consumption can potentially make a tighter adjustment of its decisions as a function of these environment variables (Cognitive Radio). The demo shows how the ALOE middleware is able to analyze computing resource consumption as well as ensure all waveform deadlines are met in a distributed multi-processor environment.

Common Data Link Quad-band Relay
Benjamin Egg (Fred Harris and Associates, USA); Fred Harris (San Diego State Univ, USA)

The Common Data Link (CDL) system is an essential DoD asset that suffers significant performance and reliability losses due to multipath interference and fading, particularly in low Angle of Arrival (AoA) operating conditions. This work was undertaken to mitigate those losses via minimally-intrusive firmware updates of existing hardware, while ensuring continuous legacy compatibility. Emphasis is given to low AoA operations. The Quad band Relay (QbR) architecture is a simple, yet powerful solution that utilizes existing hardware and additional CDL bandwidth to create link diversity. Utilizing an efficient frequency diversity architecture, link-loss due to multipath is significantly reduced. This is due to the fact the multipath losses are frequency dependent, and QbR's redundant transmissions have offset frequency centers transmitting encoded versions of the original legacy waveform. Legacy systems communicate with QbR upgraded platforms seamlessly—without hardware, software, or firmware modification. Furthermore, QbR upgraded systems receive the same transmission and are able to extract additional link gains via processing.

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