| This paper describes the state of the art in software frameworks for executing Software Defined Radio (SDR) components. These frameworks are catalyzing drastic changes in signal processing by enabling software engineers and signal processing engineers to work in tandem on core challenges, such as effectively processing large amounts of data in realtime on limited hardware resources. In addition to a historical perspective of this area, we showcase the REDHAWK framework as an example of a modern SDR framework which provides many facilities for distributed SDR deployment.

This paper describes the state of the art in software frameworks for executing Software Defined Radio (SDR) components. These frameworks are catalyzing drastic changes in signal processing by enabling software engineers and signal processing engineers to work in tandem on core challenges, such as effectively processing large amounts of data in real-time on limited hardware resources. In addition to a historical perspective of this area, we showcase the REDHAWK framework as an example of a modern SDR framework which provides many facilities for distributed SDR deployment.

Wireless Personal Communications: Bluetooth Tutorial and Other Technologies presents a broad range of topics in wireless communications, including perspectives from both industry and academia. The book serves as a reflection of emerging technologies in wireless communications and features papers from world-renowned authors on the subject. A new tutorial on the emerging Bluetooth technology is also presented. Wireless Personal Communications: Bluetooth Tutorial and Other Technologies serves as an excellent reference and may be used as a text for advanced courses on the subject. It is an essential tool for graduate students, postgraduate researchers, academics, and anyone working in the research aspect of the wireless communications industry.

This article describes the Open Source SCA Implementation:: Embedded project, an open source software development kit designed for rapid prototyping of software defined radios consistent with the Software Communications Architecture. The SCA is a product of the American military's SDR acquisition program and has played a large role in SDR development in the military and in the wireless industry. OSSIE was designed for use in wireless communications curricula and research efforts, so it is easy to learn and illustrative of software engineering, programming, and communications engineering concepts important in industrial practice today. OSSIE includes a core framework (i.e., common services enumerated in the SCA). It also includes graphical user interface-oriented tools that are easily learned and free to download and use. The tools auto-generate SCA-specific component source code and supporting files, leaving the developer to provide signal processing functionality. In addition, visualization tools for debugging and a growing library of SDR software components are available. Discussed herein are examples of SDRs designed using OSSIE, including embedded applications. OSSIE enables easy transition from concepts to practice in SDR design for communications engineers who may not have a strong software background.

We study in this paper uplink scheduling for V-BLAST users. Each user spatially multiplexes his data over multiple transmit antennas. This spatial multiplexing (SM) scheme provides high data rates while multi-user diversity obtained from scheduling improves the performance of the uplink system. The scheduler selects one user at a time based on a criterion that minimizes aggregate BER. The main results of this study show that the scheduler that maximizes the optimal MIMO capacity doesnpsilat work well for a V-BLAST system. Instead, a scheduler that maximizes the V-BLAST capacity is derived specifically from the V-BLAST detection algorithm. Furthermore, we propose and compare suboptimal schedulers that are based on the received MIMO channels before processing.

The design and implementation of the Virginia Tech Space-Time Advanced Radio (VT-STAR), a multiple antenna element space-time (ST) processing prototype testbed, is presented. The testbed is a research tool for comparing practical and theoretical performance metrics (e.g., throughput, link reliability) in different wireless channel conditions. The prototype builds around software-defined radio (SDR) concepts on a DSP platform and provides the flexibility to implement various forms of ST techniques. Different components of the system are described in detail, including the software implementation, I/O schemes with custom hardware, and data transfer mechanisms between the DSP and the host PC. Two different example realizations are presented, a real-time demonstration and an offline measurement tool. Finally, some representative measurement results obtained in indoor environments are presented. These results show VT-STAR to be a promising tool for performing MIMO experiments and generating channel measurements that can complement simulation studies in this area.

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.

ABSTRACT

Bluetooth is a standard that is designed to enable inexpensive,robust,and secure communications over short distances. This tutorial provided a general description of the Bluetooth standard, providing the reader with an overview of the potential as well as the limitations of this standard. The flexible architecture of Bluetooth opens the door to the design and inexpensive implementation of several applications that add a whole new dimension to short-range communications. The future holds great hope for short-range data communications, and Bluetooth goes a long way in setting the path to ubiquitous,integrated data services.

The peak-to-average power ratio of a signal is often used to determine the output power backoff needed to prevent spectral regrowth due the effects of nonlinear power amplifiers. It has been suggested that a better measure of the impact of a nonlinear amplifier on the transmitted signal is the envelope power distribution function. This paper presents simulation results for a multicarrier communication system showing how the peak-to-average power ratio and the envelope power distribution function change as the number of carriers increases, these results show that the envelope power distribution function is a better figure of merit than the peak-to-average power ratio for determining the impact of a nonlinear power amplifier on a communication system's BER

this paper is based on the Bluetooth specificiation [1]. This partof the paper continues the technical details of the Bluetooth specification. Part one of this paperprovided an overview of Bluetooth's market potential, capabilities, and possible applications.The technical overview of Bluetooth was started in the first part of the paper with a description ofBluetooth's position on the protocol stack as well as an overview of the connectivity methodologyemployed by Bluetooth. The second part ...

This paper presents alternate methods to generate bit errors that simulate the effect of a convolutional code on an MPEG-2 sequence. Given the complexity of Viterbi decoders, a fast way to generate bit errors that closely resembles the performance of a convolutional code/Viterbi decoder is desirable in order to minimize the execution time of Monte Carlo simulations. Three methods of generating the bit error sequences are presented in this paper. A simulation of a Viterbi decoder is used as a reference against which the proposed methods are compared. A two-random-variable method is presented that closely matches the performance of the simulation of the Viterbi decoder in both BER and PSNR. A simplification of the two-random-variable method is also presented, where only a single random variable is used, and a deterministic form of the behavior of the convolutional code/Viterbi decoder is used. This single-random-variable method yields results that are similar to the two-random-variable method, with comparable values of BER and PSNR. The statistics of the bit error distribution are sacrificed in exchange for a simplified model and less knowledge of the behavior of the Viterbi decoder. The third method proposed is a simplification of the single-random-variable method, where a single bit error is used to model whole bit error bursts. This method yields inaccurate BER estimates but also PSNR values that are biased but close to the behavior of the convolutional code.

The 10th Annual Virginia Tech Symposium on Wireless Personal Communications , held in Blacksburg June 14-16, featured what one participant described as " the strongest, most diverse technical program yet. " As always, the three-day event followed the MPRG's annual Industrial Affiliates Board meeting, in which industry representatives receive detailed briefings and demonstrations of current research and are invited to shape the MPRG's research agenda for the upcoming year. This year's symposium, which drew over 200 wireless professionals to the Virginia Tech campus, featured a tutorial and panel session on the emerging Bluetooth standard, an expanded poster session, a keynote address by one of the nation's leading telecommunications policymakers, and a panel session on entrepreneurial ventures in wireless communications. The symposium kicked off on Wednesday afternoon with a packed tutorial session on Bluetooth technology, led by Virginia Tech researchers Dr. Dennis Sweeney and Max Robert. Named in honor of a Danish king who helped unite that nation, Bluetooth aspires to provide an open industry standard for wireless interoperability between data communications devices. By providing self-configuring communications between, for example, a laptop, a printer, a handheld scanner, and a pocket calendar, Bluetooth may be a key enabling technology for the wireless office of the future. Given recent product announcements by Ericsson and Motorola among others, the subject matter of the tutorial and subsequent panel session were particularly timely. Due to the exceptional number of requests for the Bluetooth tutorial presented during the symposium, MPRG is pleased to make this presentation available on its website at http:// focused on a discussion of the future applications of Bluetooth. The panel included Mr. Phillip M. Sher with Analog Devices and Dr. Carl Panasik with Texas Instruments, in addition to Sweeney and Robert. Although panelists warned against unrealistically high expectations, noting in particular the band-width and interference limitations of the present standard, the tone was generally upbeat on Bluetooth's potential. During discussions, a few audience 'dentists' raised the possibility of a 'Bluetooth 2' or 'Bluer-tooth' standard emerging in the future. The technical portion of the program began on Thursday morning and featured a large and diverse program, with presenters from as far away as Some of the many highlights included a peek at ultra-wideband wireless propagation from David J. Hall of Time Domain Corporation, a survey of smart antennas for cellular and PCS networks by Donn Harvey of Metawave Communications, a look at optimization Continued …