In this paper we develop multiple antenna space-time decoding techniques that enable very high capacities in mobile wireless systems. The method can be implemented in small form factor handheld software defined radios. We derive a low-complexity iterative decoding scheme based on diagonal or Cayley differential encoders for multi-input multi-output (MIMO) flat-fading channels. We show that our decoding method guarantees full spatial diversity. More importantly, it bridges the gap between differential and coherent receivers. Simulation results corroborate our theoretical analysis.
Antenna systems that would enable seamless mobility using portable Software Definable Radios include a wide variety of technologies, ranging from multi-band, to tunable, to multiple-input multiple output (MIMO) antenna systems. Depending on the specific SDR application and the expected spectrum coverage, some technologies are more suitable to fulfill performance, size, complexity, and cost requirements. An overview of SDR antenna technologies suitable for mobile-phone form factors is illustrated and several technologies are comparatively analyzed. Multi- band internal antennas such as the Planar Inverted F- Antenna (PIFA) and the Folded Inverted Conformal Antenna (FICA) provide simultaneous coverage of discontinuous communication spectra. Compact antenna components that can be tune d over multi-octave frequency ranges while maintaining good radiated efficiency provide the ability to shrink antenna size while enhancing the ability to cover multiple bands selectively. Multi-antenna structures can provide ways to implement advanced communication features such as diversity or MIMO. Practical approaches for enabling a portable SDR antenna system are outlined.
Amongst many difficulties in downlink beamforming, it has been known that the problem of channel estimation could be resolved by using the auxiliary pilot channel when the dedicated pilot channel is not defined to each of the subscribers as in CDMA2000 1X signal environment. In this paper, we present a systematic procedure of utilizing the auxiliary pilot channel together with the common pilot and traffic channel. The multipath signal environment is first scrutinized in such a way that the necessary conditions for adopting the auxiliary pilot be analyzed. The performance of the downlink beamforming of a given smart antenna base transceiver station (SA BTS) is shown through the various computer simulations and experimental data which have been obtained from our SA BTS, which has been implemented for the CDMA2000 1X standard. The SA BTS shown in this paper supports all the commercial channels defined in the CDMA2000 1X standard.
The flexibility of FPGAs makes them ideal for application within Software Defined Radio (SDR). In this contribution, the implementation of Application Specific Integrated Processors (ASIP) is demonstrated on the FPGA, specifically targeting QR matrix decomposition. The ASIP comprises a number of functional units, controlled by a simple processor and associated program, and dedicated for one or more specific algorithms or operations. SDR Reconfiguration simply requires modification of the program of the ASIP, without full or partial reconfiguration of the device to meet different requirements. QR Decomposition based RLS (QRD-RLS) is suitable for a wide variety of wireless applications, including antenna processing and amplifier digital predistortion. Using the ASIP approach, it is possible to trade off size and performance to reach the optimum architecture for a particular set of requirements.
This paper discusses recent language extensions to the Gedae programming environment. The first language extension allows application developers to more easily develop modal software in Gedae’s data flow programming language. By breaking Gedae’s infinite data streams into finite length segments, mode changes become natural parts of the languages, implemented as side effects on segment boundaries. The second language extension expands the range of targets Gedae can support. Developed to support firmware targets such as FPGAs, Gedae-RTL allows developers to specify algorithms using a graphical single sample language and export that specification into code in a target language such as VHDL. Although developed for VHDL and FPGAs, the Gedae-RTL capability is generic enough that any language can be targeted. With these two language extensions, Gedae developers can more easily develop full modal software radio systems and port them to heterogeneous targets.
The understanding of fundamental approaches to designing and operating Modular Software Defined Radio (Mod-SDR) are of immediate relevance for offering flexible services to mobile users, by means of a single communication device. We review Half-Frame Pipelining (HFP) as a way of operating any software defined PHY layer on a specfic multiprocessor hardware architecture. In this paper HFP is improved against former results with respect to the runtime efficiency of its partitioning concept and the achievable speedup. A comparison to another approach, Graph Duplication Pipelining (GDP), reveals HFP's advantages and disadvantages. PHY layer signal processing for both circuit-switched and packet-switched services is discussed in detail. Finally, we conclude on the utility of HFP for application in Mod-SDR terminals.
Next generation mobile devices employ multiple programmable processing resources, which need to be orchestrated efficiently by the designer. The usage of low level operating system APIs limits the reusability of the implementation substantially. Moreover, expensive reimplementations are needed during design space explorations. An explicit and platform independent representation of parallelism within the system model on different levels of abstraction is essential for a successful and quick design process as it re lies on code generation and compilation techniques. Throughout this paper we discuss the prerequisites for a substantial support of the design process by code generation and compilation techniques and the implementation of according tool extensions. The development of the tool extensions is based on the Eclipse framework [1] and simplified parts from a WLAN 802.11b model are used as test examples for the design process.
This paper discusses the role of the Configuration Control Module (CCM) when configuring and controlling the physical resources in a wireless platform. We focus on the interfaces between the CCM and higher layer entities in the configuration plane as well as the interface to the signal processing and communication resources it controls.
Acceleration of semiconductor technologies has enabled incorporation of GPS receivers in small inexpensive hand held battery operated devices. As the size of chipsets for different communication protocols diminishes in size, building multi-protocol communication systems including GPS receivers has become not only attractive but also possible. A limitation of current approaches requires the Baseband (BB) processor to be implemented with hardware. Furthermore, if advanced techniques such as Rake receivers are desired to improve reception over multiple paths, significant additional hardware may be required. This presents both size and cost issues. In this paper we extend our work previously presented [1] by describing results for reflective environments by using a Rake receiver. The baseband processing, including the Rake receiver, is implemented entirely in software, using the Sandbridge Technologies TM Sandblaster TM Digital Signal Processor (DSP) platform. An advantage of a software approach is that differing algorithms may utilized in various environments. Using our software implementation we show that the link margin may be improved by 3dB using the Rake receiver.
The key objective of End-to-End Reconfigurability (E²R) is to devise, develop and trial architectural design of reconfigurable devices and supporting system functions to offer an expanded set of operational choices to the different actors of the value chain in the context of heterogeneous mobile radio systems.
Mobile networks are planned based on the busy hour assumption, leading to an under utilization of the available capacity during many hours of the day. Dynamic network management adds flexibility to the network planning process by introducing adaptive processes monitored by the network management subsystem, leading to reduced roll-out expenses and better utilization of resources. Dynamic network management as such enables optimal resource distribution and element reconfiguration to best suit the traffic variation in both time and space. The moving hotspot is a typical example where the need for dynamic management is highlighted. In this paper, we discuss the effect of dynamic total power distribution for the shared channel (HSDPA) in 3G network systems enabled with reconfigurable network elements. Base stations are therefore able to reconfigurable their hardware (HW) and software (SW) to work under dedicated or shared conditions. This leads to a colored HSDPA total power allocation throughout the network depending on each cell’s load. Moreover, a queuing model is introduced to simplify the key performance indicators of the shared channel and reduce the needed simulation time.
The support of reconfiguration requires the existence of negotiation procedures and trading rules connecting the device reconfiguration manager with the corresponding network proxies that will operate between the network proxies and the managed equipment, and will enable the exchange of information (e.g. mode availability, access network capabilities) or the ordering of certain procedures to take place. The task of the reconfiguration is to gather all the required software modules and carry out the individual reconfiguration steps.
This paper presents the E²R [1] regulatory research and first outcomes and recommendations. Reconfigurability implies reconfigurable equipment (terminals, base stations, access points, gateways…) and support system functions. End-to- end reconfigurability will need a very flexible regulatory approach to develop its full potential. Some changes in the regulatory framework for telecommunication may be required. This has been recognized by major regulatory bodies (e.g. TCAM, FCC) that have started to identify possibilities, threats and required regulatory changes. E2R aims to significantly contribute to this process. This will be done, by first of all addressing the current regulatory framework (material conformance, security, spectrum…) and the associated limitations and boundaries, and evaluating the impact of the E2R reconfigurability scenarios on security, privacy, placing on the market, EMC, frequency sharing rules and finally responsibilities.
In networks with transmitting users having separate un- coordinated receivers, waveform adaptation by greedy interference avoidance (IA) algorithms ([1], [2] and [3]) might not lead to fair network resource allocations. A game theoretic framework for this scenario, based on Potential game theory is presented in this paper. This model provides insight into development of algorithms that are fairer than the greedy IA algorithms and are amenable to distributed implementations.
This paper will introduce a spectrum occupancy algorithm that can detect active spectrum users. This algorithm has been employed to quantify spectrum usage at several locations, and is being used to develop frequency agile radio protocols that maximize the amount of spectrum reused and lessen the possibility of interference.
A system concept is presented which employs HYPRES superconductor micro-electronic (SME) technology to enable next-generation Broadband, Multi-band, Multi-channel MILSATCOM systems with the goal of achieving JTRS SCA compliance at frequencies covering the C, X, Ku, Ka and EHF bands. The availability of such a system offers an unprecedented opportunity to revolutionize both the purpose and performance of the MILSATCOM paradigm.
Game theory is a promising approach for analyzing the interactions of adaptive and cognitive radios. This paper describes how the components of the cognition cycle map into normal form game model and describes standard game theory techniques for investigating four important issues that game theory should address: steady state existence, steady state identification, convergence and steady state optimality. This paper then describes three game models that can aid the analyst in addressing these issues and concludes with a discussion of additional ways in which the use of game models aids the analysis and development of cognitive and adaptive radios.
In this paper, asymmetric modulation schemes are presented to establish the potential for fully adaptable signal design in cognitive radio and intelligent environments. Two categories of design are addressed, asymmetric phase-shift keying and asymmetric quadrature-amplitude modulation. The former is a phase-shift keying scheme that has been altered from symmetric form to generate a condition of phase invariance by virtue of unequal phase differences among symbols of the constellation. The later is a quadrature-amplitude modulation scheme that is based on the optimal (geometric) simplex lattice. These modulation schemes are defined by continuous and discrete parameters, which can be used to carry additional information or to adapt to unexpected changes in the environment. By tuning the parameters of these asymmetric constellations, dynamic control of bandwidth and error performance can be used to optimize channel efficiency.
The topic of cognitive radios has been garnering a great deal of attention in the past several years. Opinions regarding the level of sophistication necessary to qualify a system as cognitive vary widely, and discussions have ensued regarding this technology. The software defined radio forum is also involved and has working group activity in the area of cognitive radio. Some of the working group results are shown in this paper.
Software-Defined Cognitive Radios, which utilize voice as a primary input/output modality, are expected to have substantial computational resources that will be capable of supporting advanced speech and audio processing applications. Yet, there has been little published research regarding how to leverage these capabilities to enhance military mission capability by building on services such as speech information extraction or background noise suppression. Such capabilities go beyond interaction with the intended user of the SDR – they extend to speech and audio applications that can be applied to information that has been extracted from voice and acoustic noise gathered from other users and entities in the environment. For example, in a military environment, situational awareness and understanding could be enhanced by processing voice and noise from both friendly and hostile forces operating in a given battlespace. In this paper, we provide a survey of a number of speech and audio-processing technologies and their potential applications to cognitive radio.
We can think of a cognitive radio as having three basic parts that make it cognitive: the ability to sense, including at a minimum sensing the RF spectrum, geographical surroundings, and the user’s needs; the capacity to learn, ideally in both supervised and unsupervised modes; and finally, the capability to adapt within any layer of the radio communication system. At the Virginia Tech (VT) Center for Wireless Telecommunications (CWT), we have developed a cognitive radio engine to perform all of these tasks. This paper presents the adaptive component, which uses genetic algorithms (GAs) to evolve a radio defined by a chromosome. The chromosome’s genes represent the adjustable parameters in a given radio, and by genetically manipulating the chromosomes, the GA can find a set of parameters that optimize the radio for the user’s current needs. At the end of this paper, we present experimental results on both a hardware platform and software simulation.
As markets develop Wireless Service Providers are increasingly finding that there is an interaction between the architecture of the system they are using and the business model under which they are operating. The SDR Forum has investigated this interaction. SDRF has also made a number of documents available to its members that provide a wealth of quantitative information about the market. This paper offers an SDR Forum Business Model coupled with data originally from the Wireless Infrastructure Technology & Markets [1], hereafter Gunn, a document available to SDRF members. The specific numbers provided in this paper has been updated to reflect data available in 2004.
Driven by the desire to support “anytime, anywhere, customizable, on demand” services, wireless systems are increasingly becoming more heterogeneous and configurable. In order to alleviate the complexity of designing, deploying and managing such networks, it is useful to have a means for uniformly describing the components in these networks, at varying levels of detail. Such descriptions support tasks that involve communications with, and interaction among different hardware and software components within and between devices in networks. It is both useful and important to have a metalanguage for this purpose. Such a metalanguage must be able to interface with existing standards that are domain specific; it must also serve the needs of the various participants in the value chain, including network operators/enterprises, system manufacturers, component vendors, regulators, and end users.
This paper will present the System Scenarios that are developed within the European research project End-to-End Reconfigurability (E 2 R) [1,2]. Following the presentation of the methodology that was used to identify and define system scenarios, the three families of E²R scenarios will be introduced: (1) Ubiquitous Access, (2) Pervasive Services and (3) Dynamic Resources Provisioning. The impact on the end-to-end system in providing communications and the requirements for supporting each family of scenarios will also be addressed. This is achieved with a particular focus on the various parts involved in the reconfiguration of the communication protocol in order to cover all the layers. An analysis was also carried out to identify the E²R actors involved in the scenarios and the detailed interactions of those actors. The practicalities of implementing such scenarios from the different actors will also be discussed.
Rohde & Schwarz is one of the leading manufacturers of radios for the military market with an international presence in the fields of test and measurement, information technology and communications. Being among the first to have developed Software Defined Radios Rohde & Schwarz today has a family of SDRs in the market for airborne, tactical/mobile and stationary/shipborn applications. A review of the current status will be given in the second chapter of this article.
Software defined radio technology is achieving rapidly growing acceptance as a military communications platform because of its security advantages and its ability to be reconfigured to meet specific mission parameters. Programmable logic offers the performance, flexibility, and cost-effectiveness required for SDR systems. One of the challenges in implementing SDR designs is the long and growing list of waveforms that must be implemented in programmable logic as well as the need to be able to rapidly develop new waveforms.
New waveform requirements are pushing the limits of traditional modem design techniques. Fortunately, modern Digital-to-Analog Converter (DAC) and Analog-to-Digital Converter (ADC) can achieve sampling rates in the GHz range. These new DACs and ADCs allow designers to directly synthesize channels that have bandwidths of more than 500 MHz+; allowing either wideband or multi-channel modems to be implemented entirely in the digital domain. This eases the requirements on the Radio Frequency (RF) portion of the radio design. To fully utilize the available bandwidth of the DACs and ADCs, new techniques in modem design must be considered. Using a combination of polyphase decomposition and sub-sampling, the FPGA-based modem can provide waveform processing for the entire Nyquist bandwidth of the DAC/ADC. This paper outlines the concepts involved in implementing a wideband digital modem.
FPGAs (field programmable gate arrays) are now enjoying recognition and adoption by a wide range of software defined radio system designers and waveform developers. While FPGAs promise dramatic increases in the achievable performance levels, delivering on this promise requires careful analysis of hardware architectures, FPGA development tools, commercial FPGA IP (intellectual property) core offerings, skill levels of engineering personnel, and techniques for waveform portability and field reconfigurability.
Code portability for FPGA-based signal processing is a significant aspect of recent efforts to define a hardware abstraction layer (HAL) for the signal processing subsystems of software-defined radios. In this paper, we show how a platform-based approach to FPGA design can provide an ability to target multiple FPGA families or an ASIC from a single source model. The approach combines direct mapping of a Simulink model with code generation of register-transfer level HDL. We demonstrate that it is possible to generate portable code for DSP systems from Simulink without having to compromise performance of the FPGA realization. This work complements HAL recommendations for portability and (executable) specification by focusing on mechanisms, guidelines, and methodologies for constructing signal processing functions in FPGAs.
Commercial wireless communication terminal manufacturers are beginning to utilize reconfigurable, software defined radio (SDR) digital processing semiconductor devices and standard high level languages to implement power efficient, flexible and adaptable SDR wireless terminals. This study investigates SDR digital baseband processing resource requirements for waveforms anticipated to be employed in future military tactical communication terminals using a state of the practice, commercial, reconfigurable SDR digital processing system-on-a-chip (SOC) device.
Many software defined radio (SDR) prototypes have been developed, and SDR technology has been already applied to base stations and military radio equipment. However, it is difficult to realize a SDR terminal because of its stringent power consumption requirement. To solve this problem, NTT focused on a reconfigurable processor for an SDR terminal. We developed IEEE 802.11a software running on a reconfigurable processor and evaluated its performance by employing a simulator and an evaluation board with a real chip. The results of the evaluation confirmed that the developed software performed as designed.
The flexibility of FPGAs makes them ideal for application within Software Defined Radio (SDR). In this contribution, the implementation of Application Specific Integrated Processors (ASIP) is demonstrated on the FPGA, specifically targeting QR matrix decomposition. The ASIP comprises a number of functional units, controlled by a simple processor and associated program, and dedicated for one or more specific algorithms or operations. SDR Reconfiguration simply requires modification of the program of the ASIP, without full or partial reconfiguration of the device to meet different requirements. QR Decomposition based RLS (QRD-RLS) is suitable for a wide variety of wireless applications, including antenna processing and amplifier digital predistortion. Using the ASIP approach, it is possible to trade off size and performance to reach the optimum architecture for a particular set of requirements.
Software defined radio (SDR) mobile terminals that can access multiple wireless communication systems are the trend of the future. An SDR wideband mobile terminal must be capable of high-speed data processing and low power consumption. Reconfigurable processors with these features show promise for SDR wideband mobile terminals. We have developed a signal processing board using a reconfigurable processor for an SDR mobile terminal and software for the IEEE 802.11a wireless LAN baseband part. We evaluated the power consumption and communication characteristics of the signal processing board, and confirmed the potential of SDR mobile terminals using a reconfigurable processor. This paper describes the configuration of the signal processing board using a reconfigurable processor and shows its performance evaluation results.
This paper reviews the structure and properties of binary, and polyphase complementary spread spectrum codes, synthesis techniques to implement their code generators and code compressors, as well as a number of applications to modern communication systems.
In this paper we present the application of the PowerFFT processor – a digital full floating point spectrum processing chip – in military communication applications, such as Software Defined Radio (SDR) and Communication Intelligence (COMINT). The PowerFFT is superior in terms of performance, flexibility, footprint, and power consumption for the most demanding front-end processing operations compared to DSP or FPGA only alternatives above. The PowerFFT ASIC is combined in an SDR system architecture with FPGAs and DSPs, but relieves these devices from the heavy duty jobs required in military communications, which means that the overall architecture typically consumes less power and has a smaller footprint.
Cognitive radio (CR) is gaining widespread interest. One of the key functionalities of a CR device is free channel identification. In this paper, the complexity of the prototype filter in the IDFT filterbanks for the purpose of free channel identification is studied. Specifically, for the Kaiser windowing and equiripple approximation methods, we present the relationship between the number of channels monitored and the prototype filter parameters (number of taps, ripple, and sharpness factor). It is shown that when filter’s ripple and sharpness requirements are fixed, the number of filter taps required grows linearly with the number of channels being monitored.
A software defined radio (SDR) terminal needs to support several different air interface standards. These standards often define their own unique symbol or chip frequencies. Therefore a sample rater converter (SRC) is an essential part in such SDR terminal. This paper presents a novel architecture for sample rate converter and its implementation techniques for modulator or transmitter applications.
Multi-mode capable wireless networks are a key issue in future wireless communication. This paper introduces therefore the realization and application of a generic protocol stack as common part of a multi-mode capable communication protocol software. This can be regarded as an extension of the field of software defined radios with its origin in the physical layer on the upper layers of the protocol stack. The generic protocol stack compromises common functionality and behavior of the communication protocols that is extended through specific parts of a dedicated radio access network technology. In a bottom- up approach, this paper considers fundamental protocol functions realized as parameterizable modules. These protocol functions originally correspond to the data link layer of the ISO/OSI reference model. The system specific aspects of the protocol software are realized through adequate parameterization of the modules’ behavior. Further specific functionality and behavior can be added to the generic protocol stack through inheritance or insertion of system specific modules. Thus, the generic protocol stack enables an efficient as well as flexible realization of the protocol software as part of a future communication network of multiple radio access technologies.
Software defined radios add a degree of flexibility and versatility that is not possible with hardware based communication. However, software based on ad hoc data structures or database schemas is limited to the features explicitly supported by the software. Ontology-Based Radio (OBR) uses ontologies to add inferencing and reasoning capabilities which make radios self-aware, i.e., understand their own capabilities and the capabilities of other nodes. One important application is for radios to query each other and to interoperate in ways that are not explicitly provided by the software. We show how ontologies and rules, in combination with Java reflection, can be used to implement self-awareness and interoperability. We illustrate how such radios would interoperate by giving an example in which radios negotiate the length and structure of equalizer training sequences.
This paper elaborates on a new technique for Peak to Average Power (PAP) Control in Orthogonal Frequency Division Multiplexing (OFDM) Systems. The PAP levels are particularly problematic for Software Defined Radio (SDR) platforms, which must reproduce a large number of waveforms (possibly including OFDM) with a finite set of RF electronics, amplifiers, and Analog-to-Digital converters (ADCs). On an SDR radio, it is extremely desirable to utilize a software approach (i.e. as proposed here) to level PAP over multiple waveforms.
A major challenge of software-defined radio (SDR) is to realize many GIPS of flexible baseband processing within a power budget of only a few hundred mW. A heterogeneous hardware architecture with a programmable vector processor as key component can support WLAN, UMTS, and other standards. For handsets SDR baseband is feasible today, has many flexibility advantages, and saves silicon area.
This paper reports on the FPGA implementation of a Volterra series PA pre-distorter. The implementation of the pre-distorter and the indirect learning architecture for initializing the system is described. We supply insight into the implementation of the adaptive process itself and how the pre-distorter can exploit new generation heterogeneous FPGAs that provide a massively parallel compute fabric for demanding real- time tasks and an embedded processor for processes that have softer schedules. A recent generation visual programming design flow has been used for the implementation. The paper comments on the design productivity and efficiency aspects of the final FPGA implementation using this development environment.
The performance of communication systems is limited by the nonlinearity of the high-power amplifiers in the transmitters. Nonlinear power amplifiers create distortion that limits the dynamic range. Efforts to correct this problem decrease the amplifier efficiency while increasing the hardware complexity and cost. While it is the RF waveform that gets distorted, the conventional corrective measures (such as a compensating predistortion equalizer) are applied on the baseband signal or the intermediate-frequency (IF) signal instead, due to speed limitation of traditional semiconductor electronics. Such baseband and IF schemes are fundamentally constrained to partial correction of weak nonlinearity. It would be preferable to perform the corrections on the RF waveform directly for two major reasons: (1) near-perfect correction to even strong amplifier nonlinearity and (2) substantially simpler signal-processing circuitry.
Digital VCO and reconfigurable filter circuits are designed, and their functions are simulated in CMOS SOI 0.25µm process using Cadence spectre RF. A digital varactor is realized by using a parallel and series combination of capacitors. The oscillator can be tuned to different discrete frequencies depending on the digital control word. On the other hand, the filter can be reconfigured to one of the four types of basic filters by means of a digital control word.
GNU Radio is a code base of free software that performs signal processing using a personal computer and freely available Radio Frequency (RF) receiver front-end designs. The GNU Radio receiver is an ideal platform for learning and experimenting with Software Defined Radio (SDR) concepts. Recent efforts at NCSA have extended the GNU Radio receiver design into a 900MHz narrowband software defined radio transceiver. Our SDR transceiver is a useful tool for development of front-end hardware, algorithms, protocols, performance estimation, and operational visualization. In this paper we describe the extended hardware and software architecture for the SDR transceiver and describe a number of applications we have developed for it. One such application is SDR operational visualization software that serves as an educational tool for introducing the concepts of radio communications to novice users. Another new application is a reconfigurable communication protocol stack that includes network transport protocol layer, security layer, end-user application interface layer and a radio management layer which utilizes the SDR transceiver as the underlying communication fabric. In addition, we describe our efforts to prototype various user authentication mechanisms, such as voice pattern recognition, for unlocking specific application capabilities for specific users.
In this paper, we establish the benefits of reconfigurable antennas at the system level, and present physical embodiments of such antennas. The reconfigurability of the antenna is achieved by electronically altering the radiating aperture based on the frequency information received by an Antenna Control Unit (ACU). The ACU consists of the Field Programmable Gate Array (FPGA) and Field Effect Transistor (FET) switches. The FPGA acts as a microcontroller to toggle FET switches to effectively change the electrical length of the antennas. As we shall show, the use of separate electronically tunable transmit and receive antennas is a promising solution for realizing multi-band SDRs.
The NASA Glenn Research Center is investigating and developing suitable reconfigurable radio architectures for future NASA missions. This effort is examining software-based open-architectures for space based transceivers, as well as common hardware platform architectures. The Joint Tactical Radio System’s (JTRS) Software Communications Architecture (SCA) is a candidate for the software approach, but may need modifications or adaptations for use in space. An in-house SCA compliant waveform development focuses on increasing understanding of software defined radio architectures and more specifically the JTRS SCA. Space requirements put a premium on size, mass, and power. This waveform development effort is key to evaluating tradeoffs with the SCA for space applications.
In the last years, the tendency to have a reconfigurable receiver able to offer more than one service at the same time is growing. The receiver must be able, in general, to treat together different signals (i.e. in terms of bandwidth, modulation, received power) without any augmentation of costs of the mobile terminal. The purpose of this paper is to analyse an integration method for positioning and third generation mobile radio communication systems by means of SDR (software defined radio) technology. In general, the application of this technology introduces implementation problems especially due to the Analog to Digital Converter.
A new generation of digital audio broadcast systems has established in the past years. The common characteristic is the need for an extremely low bit rate for the source coder. Reasons are e.g. the requirement to of fer a very large number of simultaneous audio channels or an extremely narrow banded RF-carrier. Bit rates do wn to about 20 kbps are common. Today, only codecs using Spectral Band Replication (SBR) technology reach high quality audio while maintaining the full bandwidth at these lo w bit rates. The combination of SBR with Parametric Stereo (PS) technology offers a perfect stereo image at a bit rate of 20 kbps. This paper will discuss three examples using SBR-enhanced codes in the digital broadcast domain: XM Satellite Radio, iBiquity’ s HD Radio and Digital Radio Mondiale (DRM).
Increasingly powerful and dense interference, combined with imminent failure of discontinued legacy hardware, threatened a safety-related SATCOM messaging service company with catastrophic failure. CP Communication Engineering Corporation (CP Comm) was contracted to design and build new CDMA hub equipment to replace the ailing legacy hardware, under extreme deployment time constraints, provide improved performance as well as implement anti-jam (AJ) to overcome the new and emerging interference environment, while maintaining uninterrupted service to the thousands of mobile terminals in the field. CP Comm’s seven years of SDR experience combined effectively with timely availability of new DSPs from Texas Instruments and digital radio components from Analog Devices to provide beta units to the customer within six months, in time to avert the business catastrophe.
The Software Communications Architecture (SCA) Version 2.2 and the Application Programming Interface (API) supplement have been in existence since November 2001. The objective of the SCA is to foster an open architecture in which waveforms/applications are portable across a wide range of SDR implementations. There have been many incarnations of the Core Framework specified by SCA V2.2 however, to this point in time there have not been any APIs for Radio Services or Radio Devices which are unencumbered by intellectual property rights published for the community. The lack of publicly available APIs for Radio Services and Devices is inhibiting the progress of Software Defined Radio technology both from a hardware platform and SDR application vendor perspective. This lack of publicly available unencumbered APIs leads to proprietary single point implementations of waveforms and Radio Services and Devices. There are several factors that may be inhibiting the development of an open architecture SDR: 1) No commonly accepted definition of a set Radio Services and Devices which are part of a SDR platform; 2) No Naming conventions; 3) No commonly accepted content and format for an API. Current API standardization efforts within the SDR Forum and the OMG [1] have shown promise yet do not establish interfaces down to the level of method invocation signatures necessary for portability.
This paper presents a generic Communication System Architecture for a multi-band SATCOM radio that is capable of operating at high data rates and that allows enhancement to support a dynamic network routing capability. Using domain knowledge of the Milstar, AEHF, and SHF SATCOM systems, a functional decomposition is suggested that provides maximum reuse of SCA components for the development of radios with widely varying platform requirements, from stationary ground radios to ship and airborne mounted platforms. A method to assess what requirements each component must satisfy is discussed. Component categories are defined that allow components to be grouped according to their overall purpose and function within the radio. This leads to the establishment of a set of common SCA components that support all radio platforms. A discussion ensues identifying the functions provided by each component along with the key requirements satisfied by each.
Rockwell Collins has demonstrated an above 2 Gigahertz (GHz) beyond line of sight Satellite Communication (SATCOM) radio that implements the Software Communication Architecture (SCA) for a Military Satellite Communication (MILSATCOM) Waveform. The demonstration system was used to verify the capability to implement Military Strategic, Tactical And Relay (MILSTAR) waveforms using the SCA. The project included the use Commercial Off The Shelf (COTS) Portable Operating System Interface (POSIX) compliant operating system and open source Common Object Request Broker Architecture (CORBA) Object Request Broker (ORB) to enhance the porting of a complex waveform. The system was used as a proof of concept demonstration for the MILSTAR waveform Low Data Rate (LDR), as well as a test platform for high data rate analysis. This paper discusses the design and integration, porting issues and lessons learned from the project. Presentation material will include future goals and ongoing activity related to high speed data communications using 1 Gigabit (Gb) Ethernet for high speed satellite communications that exceed those of traditional High Frequency (HF) / Ultra High Frequency (UHF) / Very High Frequency (VHF) waveforms.
The Joint Tactical Radio System (JTRS) Software Communications Architecture (SCA) provides an initial baseline for the common configuration, initialization, and coarse-grained management of a set of resources that, when integrated in a cooperative fashion, form a software-defined radio. Policy evolution has expanded the range of application of the SCA to all communications systems up to 55GHz. The architectural impacts these higher capacity radio systems present are significantly different that those addressed by the initial JTRS procurements. This paper presents an overview of architectural issues and tradeoffs associated with developing an SCA-compliant, high capacity radio system. These issues and tradeoffs will be presented in conjunction with solution spaces enabling the development of a system that meets more than the base set of SCA requirements. An overview of a working reference implementation of a radio system that supports up to 300 Mbps, operates in the 15GHz range, and is configurable and re-programmable under SCA control will be presented.
The Joint Tactical Radio System (JTRS) Program is a key U.S. DoD transformational program with the purpose of supporting the U.S. DoD objective for information superiority on the battlefield. The JTRS Program is a driving force behind the advancement of U.S. Military Software Defined Radio (SDR) solutions and associated technology to meet today’s and tomorrow’s war-fighters’ needs. Military SDR solutions are evolving towards JTRS compliance. This evolution requires continued maturation of the JTRS Software Communications Architecture (SCA) including the Operating Environment (OE) and definition of Application Programmer Interfaces (APIs), the development of standard waveform applications, and the incorporation of key technologies, such as programmable security. This paper discusses the some key objectives and issues with JTRS Program evolution to full compliance and beyond. In addition a description of JTRS security solutions with Sierra ™ II is provided along with a summary description and final performance data for the Harris JTRS Step 2B program.
The Software-Defined Radio (SDR) research community currently needs an implementation of the SCA core framework (CF) that is open to modifications, free, simple, and in C++. Recognizing this need Virginia Tech has developed and released OSSIE (Open Source SCA Implementation::Embedded). This paper describes the underlying philosophy for the development of OSSIE, the basic structure of the released framework, shortcomings to the current implementation, available sample waveforms, and a research path for the implementation.
High-level “frameworks” such as the SCA (Software Communication Architecture) add virtualization layers on heterogeneous DSP-FPGA systems with the promise of code portability., However, there is an impact on performance and complexity. This paper takes a look at these aspects by using a design example consisting in the design of a GSM waveform compliant with the SCA framework. More specifically, this paper takes a look at the lower level detail aspects of developing the IF and baseband processing components of the SCA waveform on a FPGA and a DSP, respectively Moreover, the project is executed using the model-based/system-level development tool MATLAB®/Simulink® to improve testing and productivity, and bridge modeling and implementation phases.
System designers building their waveform components with the goal to address the portability and flexibility features of the SCA have simultaneously to cope with two opposite topics: the real time requirements of their applications and the middleware behavior which exhibits transport overhead and reduced determinism (higher jitter, latency). This paper present an innovative “asynchronous” design approach, currently experimented by Thales Communications S.A. inside the “Software Radio Architecture” program through the design of an SCA compliant FM3TR waveform, and put this activity in perspective for the development of new High Data Rate waveform exhibiting IP networking features.
UML Profile for Waveform SPS Abstraction (paper not available) Bulteau, Nicholas/G. Gogniat, S. Rouxel, J. Diguet, C. Moy, J. Goubard, A. Delautre; Mitsubishi
This paper proposes to address the issue of a priori verifying, at the architectural design phase of both software and hardware, the adequate operation of a software radio protocol stack application on a hardware platform in terms of real-time execution, power consumption, memory size, circuit surface (gate), communication media dimensioning.
Compared with the analog hardware based radios of past years, the modern software-defined radio provides an unparalleled degree of capability and versatility, enabling complex waveforms that were inconceivable in the past to be implemented with ease. Legacy waveforms and the systems dependent on them continue to persist in the present day, however, and the new technology has challenges meeting certain parameters that were not issues in older, analog radios. Data throughput delay, the end-to-end time required to transmit data through a radio system, is one of these “problem” parameters.
In “Development of Software Radio Prototype” [1] presented during the 2002 SDR Forum Technical Conference, we reported on a prototype SDR which provides various types of analogue/digital modulation, two full duplex channels, and a frequency range of 2-500MHz, evaluating hardware design approaches for multi-band, multi-mode SDR. Succeeding this, in “Software Architecture and Waveform Applications of Software Defined Radio Based on SCA v2.2”[2][3] presented during the 2003 same conference, we reported on an improved prototype with upgraded hardware and adoption of the SCA v2.2, examining our software architecture approach and waveform applications. There, we commented “Having some doubts about the necessity of the interface definition for devices which generally do not provide software portability, we reserve application of these interfaces defined in SCA v2.2 until it becomes clear”.
Software radios offer an unprecedented degree of flexibility to designers of wireless networks. SDR enables dynamic modification of physical layer parameters which can be used to improve overall system performance. However, it is difficult to exploit this opportunity. Excessive flexibility leads to networks that are complex to implement, verify and manage safely, resulting in compatibility problems, high maintenance costs, and possibly worse performance than static wireless networks. This paper explores the applicability of layering as a structuring mechanism to reduce the complexity. We report our experience with implementing a waveform that supports packet-by-packet variation of modulation, symbol rate, and other parameters. One interesting result is a requirement on signal processing middleware packages to provide greater application-level scheduling control.
More than ever, commercial, government, and military organi-zations are demanding that developers use POSIX interfaces. The question is, how much of the POSIX standard must your project support? POSIX is so large, and has so many optional components, that few applications need everything it offers. This session introduces basic concepts of application portability and explores the benefits of using POSIX as a standard for achieving greater levels of portability. It examines how to: identify which POSIX APIs your system requires; determine whether your OS can support those APIs; achieve portability without sacrificing performance; and weigh the relative merits of POSIX conformance, POSIX compliance, and POSIX certification. Examples related to portability are examined from the perspective of various editions of the POSIX specifications.
The United States Department of Defense has specified a CORBA based Software Communications Architecture (SCA) as part of a procurement specification for the family of Joint Tactical Radio System (JTRS) Cluster radios. The JTRS Cluster radios are a family of software defined radios (SDR) requiring a high-assurance, secure architecture employing NSA Type 1 security and other stringent security architecture requirements [1].
This paper describes how SCA descriptors can be automatically generated from sets of UML diagrams. It explains the mappings from UML models and their graphical representation to XML. The relationship of this work to other aspects of SCA component implementation is explained, and also the relationship to other MDA approaches and aspects. Finally, initial results in this area using a commercial tool are briefly described. The main finding of this paper is that SCA Domain Profile descriptor defects can be reduced, descriptor creation time can be greatly reduced and the need for scarce technical resources can be minimized by modeling graphically and applying MDA techniques.
This article describes the developments in the field of emerging new military radio systems to be deployed in Finland. Finnish software radio programme is the tool to deploy these new systems. The demonstrator platform, that is being build, is a software defined radio wherein the developed wideband applications can be demonstrated. The systems that will be deployed on the demonstrator platform - Tactical Radio Communication System (TRCS) and National Tactical Positioning System (NTPS) - are introduced in this paper. Brief introduction of the adaptive antenna system to be applied in the demonstrator is also given.
Software Defined Radio (SDR) application developers increasingly want to exploit the performance and power of different combinations of modern Digital Signal Processors (DSPs), FPGAs and general purpose processors (GPPs). As such, radios are being realized with different physical topologies, with different combinations and numbers of such processing elements in them today. This paper talks about the consequent motivation for the use of an ‘SCA-machine’ that stretches over all three classes of processor and normalizes the hardware from the perspective of the waveform: with the aim of maximizing hardware independence and providing a common API, supporting waveform “plugability” and portability, etc.
Future wireless terminals will have to be multi-band, multi-standard and able to execute multiple standards concurrently. In this paper we describe a flexible and programmable baseband platform for a large variety of mobile and WLAN standards. For the SDR platform architecture our primary design goal was to find the most flexible and easy-to-program solution within a specified power budget. The result is an architecture consisting of a cluster of four single-instruction multiple-data (SIMD) DSP cores each containing four processing elements and operating at 300 MHz. The cluster of SIMD cores is accompanied by dedicated processors for filtering operations, and channel encoding and decoding. The programming environment of this platform consists of an application programming interface (API), compiler and debugger, and a virtual prototype of the hardware. Profiling results for the digital signal processing software performing the PHY layer of IEEE 802.11b on the virtual prototype underline the feasibility of our approach.
This paper provides a summary of the main features of technical operation of a pool of processing platform, including:
Switch fabric and system software supporting: • Maximum utilization of all processing resources for waveform and processing tasks • Deterministic, wideband data communication simultaneously among all processing resources
FPGA in-mission dynamic reconfiguration
Component-based middleware enabling 1 and 2 above
Support of software communications architecture (SCA) personalities
Small form factor packaging This paper also describes how these technical performance features support the needs of joint tactical radio system (JTRS) and software radio, including numbers of simultaneous waveforms and channels, scalability, flexibility, commercial off-the-shelf (COTS), technology insertion, economical spiral support, and low life-cycle cost.
A prototype waveform interoperability system has been built by Vanu, Inc. for the US Army U.S. Army Communications-Electronics Command (CECOM). The system enables law enforcement and public safety agencies with incompatible radio devices to communicate with each other.
Reconfiguration involves besides setting of configuration parameters also the download of reconfiguration software. The basic approaches for secure software download are to verify that the software originated form a trusted source (signed by a trusted provider), and the execution in a controlled, restricted execution environment (sandbox). This paper describes approaches for secure download of SDR software, i.e. software that defines or modifies wireless communication properties of mobile devices.
The software development community is rapidly accepting the use of open source software in business and mission critical applications. At the same time, software attacks are taking an increasing toll on business and society. Such assaults have recently been detected in embedded software, foretelling a trend toward malicious attacks on every day digital devices.
Software defined radios (SDR) are rapidly becoming a mainstream technology for co mmercial, civil and military mobile terminals and wireless access points. Moreover, “wireless Internet” waveforms with weak security designs, such as IEEE 802.11 Wireless Fidelity (WIFI), a form of wireless local area network (WLAN), are becoming increasingly prevalent. Because WIFI enabled laptop computers and personal digital assistants (PDA) combine a radio and computing interface, they provide a useful case study examining potential dangers posed by hackers to networks of software defined radio terminals.
Security in a communications system is the attribute that ensures that authorized traffic content is accurately delivered only to intended recipients and that use of system resources is accurately recorded. Introduction of RF links in mobile wireless introduces security considerations beyond those of wireline telephony because interception of the signal cannot be prevented. Implementation of radio links with software defined radio (SDR) technology requires further security measures to preclude introduction of software that can compromise existing security measures.
Recently, several simulation tool manufacturers have introduced a number of personal productivity tools that allow direct interaction between the simulation environment and the Texas Instruments family of Digital Signal Processors. Based on direct interaction with Code Composer Studio as well as the JTAG-based RTDX interface developed by Texas Instruments, these tools significantly enhance signal processing algorithm development by submitting DSP-resident software to realistic simulations of actual signal conditions. Since RTDX is common to the TI C5000, C6000 and OMAP DSP families, a single tool can be used to develop software on all of these popular TI devices.
In this work, the state-of-the-art RF synthesis tools for non-linear RF and analog integrated circuits are discussed. Several commercial tools are compared and presented. For RF and non-linear analog circuits, due to the non-linearity of the circuit, design optimization is not a trivial task. This paper will give an overview of the synthesis tools for RF and Analog IC, with emphasis on trade-offs in terms of noise and distortion.
Software centric approach to developing wireless Applications (paper not available) Jinturkar, Sanjay/Y. Nacson, V. Ramadurai, S. Shamsunder, M. Moudgill, J. Glossner; Sandbridge
There is an increasing focus on implementing complex wireless applications in software. Software implementation enables re-configurability and lowers the development costs. Such an implementation is frequently done in a higher level language such as C. The implementation process has two major components - A well architected C code, followed by efficient compilation and execution of it on the target platform. In this paper, we focus on the software implementation of 802.11 physical layer using the Sandblaster tools [2] for the Sandblaster multithreaded processor [1] .
This paper presents the implementation of a solely Cordic based linear equalizer for CDMA (including descrambling and dispreading) on a software defined architecture. The performance of this approach is compared to the Rake receiver. We formulate the different detection concepts in a common matrix notation and discuss their performance in an UTRA-FDD environment. Simulations confirm the presented results.
Software-Defined Radio (SDR) is a rapidly evolving technology that is receiving enormous recognition and generating widespread interest in the telecommunication industry. Over the last few years, analog radio systems are being replaced by digital radio systems for various applications in military, civilian and commercial areas. In addition to this, programmable hardware modules and high performance Digital Signal Processors (DSPs) are increasingly being used in digital radio systems at different functional levels. SDR technology facilitates implementation of some of the functional modules in a radio system such as modulation/demodulation, coding, signal generation, and link-layer protocols in software. This helps in building reconfigurable software radio systems where dynamic selection of parameters for each of the above-mentioned functional modules is possible. A complete hardware based radio system has limited utility since parameters for each of the functional modules are fixed. A radio system built using SDR technology extends the utility of the system for a wide range of applications that use different protocols and modulation/demodulation techniques.
This paper presents a novel spectrum-allocation technique designed for a high data-rate and spectrally-efficient multiple-user wireless system. The core of this system is a reconfigurable radio, implemented on a General-Purpose Processor (GPP) platform. A type of Dynamic Orthogonal Frequency Division Multiplexing Multiple Access (DOFDMA) is used to transmit a multiplex of several information sources. A novel means of sub-carrier allocation is utilised allowing the spectrum allocation for each service to be varied according to the spectrum-usage at the time of the request and priority of the particular service. In addition a novel technique that enables frame synchronisation, carrier-frequency offset estimation and a means of notifying the remote receiver(s) of the sub-carrier allocation using a single OFDM symbol will be presented. A prototype model for the Multiple User Data Enhanced Radio Server (MUDERS) modulator will be presented, focusing on a means of conveying the spectrum allocation information to a remote receiver(s).
Since there is no compatibility between the existing different communication systems, networks must be independently constituted in a present day. However, a network can be constituted, even when different communication systems are used together , by using a software defined radio (SDR) function in the base station of a network. Here, if SDR is put in to practical use, it is possible that conventional terminals, whose communication systems are fixed and terminals with the SDR function s are both used in a communication environment. In this network, when a base station controls the wireless resources of all terminals, communication while considering the influence of mutual communication is realizable and improvement in the throughput of the network can be expected. In this paper, the resource allocation method in a base station is considered, and the throughput in a network of Wireless LANs is analyzed.
The wireless world is migrating towards the era of Beyond the 3 rd Generation (B3G) wireless communications. A major contributor towards this convergence is reconfigurability , which provides technologies that enable terminals and network segments to dynamically adapt to the set of RATs, which are most appropriate for the conditions encountered in specific service area regions and times of the day. Reconfigurability poses requirements on the functionality of wireless networks. This paper presents challenges that have to be met, in order to realize the reconfigurability concept. The paper will present the views and work conducted in the context of the Working Group 6 (WG6), “Reconfigurability”, of the WWRF.
Mobile networks are planned based on the busy hour assumption, leading to an under utilization of the available capacity during many hours of the day. Dynamic network management adds flexibility to the network planning process by introducing adaptive processes monitored by the network management subsystem, leading to reduced roll-out expenses and better utilization of resources. Dynamic network management as such enables optimal resource distribution and element reconfiguration to best suit the traffic variation in both time and space. The moving hotspot is a typical example where the need for dynamic management is highlighted. In this paper, we discuss the effect of dynamic total power distribution for the shared channel (HSDPA) in 3G network systems enabled with reconfigurable network elements. Base stations are therefore able to reconfigurable their hardware (HW) and software (SW) to work under dedicated or shared conditions. This leads to a colored HSDPA total power allocation throughout the network depending on each cell’s load. Moreover, a queuing model is introduced to simplify the key performance indicators of the shared channel and reduce the needed simulation time.
The plethora of radio access systems and therein the number of different terminals used to connect to them, have generated the need for simple to use ‘any-standard’ terminals. Such kind of terminals will be capable of reconfiguring themselves not just on the physical layer but also the system components on protocol stack and upper layers. A clear concept is needed to approach and eventually satisfy the requirements such terminals will have. To overcome the heterogeneity of the access systems, an approach introducing a reconfiguration plane, to support the modelling and implementation of a multi-layer reconfiguration system (physical- and upper system layers), had been proposed, the practical modelling of this plane is presented in this paper.
For multiple standard data communication purposes run-time re-configurability of the used air- and line interfaces is a preferred feature. Additionally to run-time re-programmable channel- and baseband-processing cores, a universal multimode forward error correction channel codec ASIP (application specific instruction processor) is a useful IP-core for application in software radio and storage applications. In this work, the concept and a prototype of a multimode codec processor ASIP was designed and verified. The required degree of flexibility and efficiency is attained by a pipelined Harvard like multi- processing architecture approach with dedicated hardware acceleration for the individual coding- and decoding tasks. The design is based on MatLab, C++, SystemC and HDL. Results on the design and the verification are presented.
In this paper we will discuss the RF front-end architecture for software definable radio (SDR). The paper will discuss various architectural issues for a homodyne Zero-Intermediate Frequency (ZIF) multi-band receiver. The RF Receiver is capable of handling Wide-Band CSMA (WCDMA), GSM, and 802.11 Wireless LAN standards. The RF circuits of the receiver Low-Noise Amplifier (LNA), Mixer, and the IF Filters are presented.
In this paper, w e propose a concept of a new receiver structure with diversity reception technique to realize multi-service simultaneous reception, which shares diversity branches between receiving communication services. In the proposed receiver structure, each diversity branch selects the receiving services dynamically according to channel states, and each communication service is always selected by at least one branch to realize multi-service simultaneous reception. A basic algorithm is also described to select combinations of a diversity branch and a receiving communication service . The total number of branches decreases and the effective number of branches per communication service increases, by sharing the branches between communication services in the proposed receiver. Simulation results are shown that the proposed diversity receiver achieves both complexity reduction and performance improvement.
The Centre for Telecommunica tions Value Chain Driven Research (CTVR) approach to software radio is to focus on the use of a general-purpose processor (GPP). The use of a GPP to perform signal processing for communications applications presents the developer with challenges but it also presents some opportunities. We argue new classes of algorithms are required which will exploit the advantages and negate the disadvantages of using a GPP. Indeed other researchers have already started this programme of ‘algorithmic advances’. This paper discusses the issues involved and reviews some existing developments. We present our own progress in developing a noise adaptive symbol synchroniser and we discuss some initial thoughts on how these techniques may be applied to radio functions generally.
An Application Program Interface (API) for a radio transmitter is defined that accommodates various analog and digital configurations. In addition to up-conversion - perhaps using one or more digital or analog stages – controls affecting gain, ba ndwidth, and timing should be visible that support all modulation types and access protocols. Furthermore, whereas traditional radio transmitter topology maps one conversant with one transmitter, software radio can accommodate several conversations over several carri ers on a single transmitter. Each carrier can have individually configured bandwidths, power levels and modulation ty pes. With the addition of low power and small form factor requirements, conventional IQ modulators and surface acoustic wave (SAW) filters begin to run into efficiency and linearity problems that erode their performance in multimode applications.
This paper introduces a novel wide-band polar digital transmitter (DTx). The design integrates several functions, including I/Q to polar conversion, phase modulation, amplitude modulation, phase/amplitude combining, and RF power amplification . The basic functionality and advantages of the DTx are presented. In addition, measured results for cdma2000 and GSM/Edge cellular technology are provided to demonstrate the performance capabilities of the proposed DTx architecture as a multi- mode-multi-band transmitter, which is an essential advantage from the software defined radio applicability.
In this work, a mode identification system for superimposed signals in the same band is presented. More precisely, a signal processing technique, namely the Wigner-Ville distribution, combined with non parametric (k-Nearest Neighbors and Parzen) and Neural Network classifiers is proposed for identifying the transmission modes in an indoor wireless environment. A reconfigurable terminal based on Software Defined Radio technology is considered aiming at the identification of the presence of two co- existent communication modes such as Bluetooth, based on Frequency Hopping - Code Division Multiple Access, and IEEE WLAN 802.11b, based on Direct Sequence - Code Division Multiple Access. Results in terms of error classification probability, expressed as relative error frequency, will be provided with a comparison among the classifiers.
Digital transmitters and receivers are vital elements in any software radio system. This paper considers the practical hardware requirements of a number of typical digital modulation schemes. It deals with both the digital processing resources and the analog characteristics required of both input and output paths. Pentland Systems has recently developed a demonstration system designed to switch, under software control, between two, disparate modulation schemes. The paper describes the design of the demonstration system (including using FPGAs for DSP) outlines some of the problems encountered and their solutions. The paper ends with a discussion of the results achieved by the system.
Accurate positioning is an essential element of next generation Software Defined Radio (SDR) applications such as cognitive radios, telematics, and E-9-1-1, leading to an increased demand for GPS waveforms on SDR platforms. The Software GPS Receiver (SGR) developed in-house at NAVSYS implements functionality largely in software, and uses a reprogrammable hardware platform that can also be configured to perform other communication functions. Further, the sensors compatible with this system can provide GPS, wireless, inertial, and image information for a diverse set of applications. The low cost PC/104-based SDR test bed developed at NAVSYS can input communication and GPS signals operating at different frequencies using up to eight Digital Antenna Elements (DAE). A PC/104 compatible Field Programmable Gate Array (FPGA) card is used to perform high-speed signal processing operations. This paper presents the design of the PC/104-based test bed that can be used for developing and testing GPS and other basic communication waveforms for SDR applications.
A Vision of the Next-Generation Superconductor-Enhanced MILSATCOM System (paper unavailable) Littlefield, Wes/J. Rosa, D. Gupta; HYPRES
A system concept is presented which employs HYRPES superconductor micro-electronic (SME) technology to enable next-generation Broadband, Multi-band, Multi- channel MILSATCOM systems with the goal of achieving JTRS SCA compliance at frequencies covering the C, X, Ku, Ka and EHF bands. The availability of such a system offers an unprecedented opportunity to revolutionize both the purpose and performance of the MILSATCOM paradigm.
Session 4.5
Maximizing Mission Life: Power Management for Software-Defined Radio Ethier, Sheridan; QNX Software Systems
Software-defined radio is inherently flexible, yet that very flexibility poses numerous challenges for the system designer — such as finding an equally adaptable model of power management. Unfortunately, existing power management standards, with their roots in general-purpose computing, provide a “one size fits all” approach that fails to address the unique, and highly variable, usage scenarios that a software-defined radio may need to address. The problem becomes particularly acute with software-defined tactical field radios, which require power management mechanisms that can be finely tuned to ensure the longest possible mission life. Implemented correctly, such mechanisms can intelligently restrict the draw of various components (e.g. transceiver, modem, vocoder) during periods of little or no communication, while ensuring the radio continues to meet all of its functional requirements.
A SDR Ultrawideband Impulse Communication System for Low and High Data Rates Moy, Christophe/S. Paquelet, A. Bisiaux, Ph.D, A. Kountouris, Ph.D.; Mitsubishi
The paper proposes a new way of considering software radio in the specific context of UWB. Due to the extremely wide-band nature of UWB signals, it is shown that a first stage of analog pre-processing is mandatory to make SDR applicable in this context, in other words to obtain flexible or multi-purpose UWB systems. But not any analog front- end is convenient. It must be generic enough in order to fully take benefit from SDR capabilities. The proposed solution is based on two different analog structures for impulse UWB.
Micro-Power FinFET RF Front-End for Embedded Wireless Systems Hutchens, Chris/J. Wang, J. Popp, Y. Zhang; Oklahoma State Univ
A micro-power RFIC front-end, a low-noise amplifier (LNA) combined with a voltage controlled oscillator (VCO), has been designed using FinFET BSIMSOI model, which is developed for all FinFET transistors fabricated at the SPAWAR system center. The LNA power consumption is 26 μW at 0.5V supply and the VCO power consumption is 29 μW at 0.5V supply.
Power Management Strategies for Software Defined Radio Platforms Palum, Lloyd; Harris
In recent years it has become clear that software defined radio platforms provide the benefit of allowing independent evolution of hardware and software components. Advances in silicon technology can be independently realized without losing or re-implementing platform and application software. Applications can be enhanced and new applications can be introduced without the loss of investment in the current platform. This loose coupling of radio system components beneficially facilitates independent component evolution, although it can make some user critical performance features more difficult to achieve. Power management in portable battery powered software defined radios is one such feature. In this paper, we consider one possible approach for accomplishing power management in the context of an SCA-compliant Software Defined Radio architecture.
Broadband, multi-carrier, software-defined radio (SDR) mobile wireless network infrastructure is directly applicable to the emerging WiMAX ® 802.16 technology, particularly the 802.16e mobile high-speed data requirements. Orthogonal Frequency Division Multiplexing (OFDM) waveforms, as used in the 802.16 technology, can be very efficiently implemented using Fast Fourier Transform (FFT) techniques to provide significant architecture advantages.
HYPRES Superconducting MicroElectronics (SME) Technology provides unparalleled performance improvements in the digital domain allowing, for the first time, the direct digital conversion of RF signals while enabling the use of advanced ultra-high speed digital signal processing techniques. SME makes it possible to take the receive (or transmit) signal directly at the output of the base station antenna and directly convert (ADC) it into the digital format for further processing. The ultra low noise, high speed and sensitivity of the HYPRES Digital-RF allows spectrally pure frequency conversion and signal demodulation. Our technology affords many, hereto for unobtainable, benefits that can significantly improve the performance and cost of commercial wireless networks and base stations.
This paper explains what the type of fundamental features that software definable radio (SDR) products must possess to function as true software radio (TSR). It will examine the evolutionary path of such products from software assisted radios (SAR) which are hybrid in nature utilizing signal processing in analog as well as in digital form to true software radio system. The latter, exemplified by TechnoConcepts, Inc’s. TSR system, an industry first, does all signal processing in software by converting the received signals into digital form immediately after an antenna. It provides a new qualitative leap in frequency agility as well as protocol standard independence and solves the problem of system incompatibility in a highly fragmented communication environment.
This contribution reports about the design and lab implementation of a Multiband Frontend (MBFE) for a 3G Medium Range Basestation, achieved in the scope of the German research project RMS (Reconfigurable Mobile Communication System), embedded in the framework program “Mobile on Chip” [1] .
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