Papers by Costas Georghiades
1991 American Control Conference, 1991
We investigate the problem of communication between road-side infrared beacon and moving automobi... more We investigate the problem of communication between road-side infrared beacon and moving automobile. The various noise sources are investigated and a worst-case throughput and error probability are determined.
Information Technology: Transmission, Processing and Storage, 1996
We look at the well studied problems of sequence estimation in unknown or fading channels, and in... more We look at the well studied problems of sequence estimation in unknown or fading channels, and introduce yet another set of algorithms that have reasonable complexity and perform well even in fast changing environments. The algorithms work on a block-by-block basis and utilize periodically, but sparsely inserted known data symbols. In producing their channel estimates, however, the algorithms do make use of the information contained in the received modulated data, thus reducing the rate at which known symbols need to be inserted, and improving performance. Simulation results show good performance for the algorithms.
IEEE COMMUNICATIONS LETTERS, 2002
We show how low-density parity-check (LDPC) codes can be used to compress close to the Slepian-Wo... more We show how low-density parity-check (LDPC) codes can be used to compress close to the Slepian-Wolf limit for correlated binary sources. Focusing on the asymmetric case of compression of an equiprobable memoryless binary source with side information at the decoder, the approach is based on viewing the correlation as a channel and applying the syndrome concept. The encoding and decoding procedures are explained in detail. The performance achieved is seen to be better than recently published results using turbo codes and very close to the Slepian-Wolf limit.
2007 16th IST Mobile and Wireless Communications Summit, 2007
Transmit beamforming can improve the performance of multi-input multi-output (MIMO) systems. For ... more Transmit beamforming can improve the performance of multi-input multi-output (MIMO) systems. For FDD systems, the beamforming matrix must be quantized and fed back to the transmitter side. Different compact quantization codebooks have been designed to reduce the overhead of the feedback channel. In this paper, we compare the performance of two different quantization methods for a fixed codebook: vector- wise
This report is a theoretical analysis of several communications techniques that will be useful in... more This report is a theoretical analysis of several communications techniques that will be useful in the full implementation of IVHS technologies. The report is a continuation of the work completed in Part I. It looks at some of the communications problems that have been mentioned as bringing some difficulties to spread spectrum, such as the near-far problem. The report also investigates the simulation protocol that could be used with spread spectrum radio to allow for individualized messages to be sent from traffic management centers to vehicles. The use of infrared as a multi-access communications technique is also investigated. Infrared was chosen since it is the system that is used by Semens in their Lisb and Autoguide systems of vehicle navigation. The third chapter discusses a totally different type of communications. This chapter looks at using radio frequency transponders on vehicles to determine the exact lateral and headway between vehicles. The Path program in California is ...
15th International Communicatons Satellite Systems Conference and Exhibit, 1994
Journal of Communications and Networks, 2000
Eurasip Journal on Advances in Signal Processing, 2004
Space-time block coding (STBC) provides substantial diversity advantages with a low decoding comp... more Space-time block coding (STBC) provides substantial diversity advantages with a low decoding complexity. However, these codes are not designed to achieve coding gains. Outer codes should be concatenated with STBC to provide additional coding gain. In this paper, we analyze the performance of concatenated trellis-coded STBC schemes over shadowed Rician frequency-flat fading channels. We derive an exact pairwise error probability (PEP) expression that reveals the dominant factors affecting performance. Based on the derived PEP, in conjunction with the transfer function technique, we also present upper bounds on the bit error rate (BER), which are further shown to be tight through a Monte-Carlo simulation study.
Ieee Transactions on Information Theory, Sep 1, 1994
Optical direct-detection systems are currently being considered for some high-speed intersatellit... more Optical direct-detection systems are currently being considered for some high-speed intersatellite links, where data rates of a few hundred megabits per second are envisioned under power and pulsewidth constraints. In this paper we investigate the capacity, cutoff rate, and error-probability performance of uncoded and trellis-coded systems for various modulation schemes and under throughput and power constraints. Modulation schemes considered are on-off keying, pulse-position modulation (PPM), overlapping PPM, and multipulse (combinatorial) PPM.
Circuits, Systems and Computers, 1977. Conference Record. 1977 11th Asilomar Conference on
ABSTRACT
Optical direct-detection systems are currently being considered for some high-speed intersatellit... more Optical direct-detection systems are currently being considered for some high-speed intersatellite links, where data rates of a few hundred megabits per second are envisioned under power and pulsewidth constraints. In this paper we investigate the capacity, cutoff rate, and error-probability performance of uncoded and trellis-coded systems for various modulation schemes and under throughput and power constraints. Modulation schemes considered are on-off keying, pulse-position modulation (PPM), overlapping PPM, and multipulse (combinatorial) PPM.
Page 1. ICC'12 CT: IEEE ICC 2012 - Communications Theory - Committees and Welcome fu... more Page 1. ICC'12 CT: IEEE ICC 2012 - Communications Theory - Committees and Welcome func_welcome(): message does not exist. Technical Program Committee Raviraj Adve University of Toronto Canada Jeffrey Andrews The University of Texas at Austin USA Amir Banihashemi Carleton University Canada Dror Baron North Carolina State University Israel Gerhard Bauch Universitaet der Bundeswehr Munich Germany Norman Beaulieu University of Alberta Canada Matthieu Bloch Georgia Institute of Technology USA ...
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Papers by Costas Georghiades