Watcharapan Suwansantisuk

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Cooperative diversity techniques can improve the transmission rate and reliability of wireless networks. For systems employing such diversity techniques in slow-fading channels, outage probability and outage capacity are important performance measures. Existing studies have derived approximate expressions for these performance measures in different(More)
In this paper, we propose a search technique that takes advantage of multipath, which has long been considered deleterious for efficient communication, to aid the sequence acquisition in dense multipath channels. We consider a class of serial-search strategies and use optimization and convexity theories to determine fundamental limits of achievable mean(More)
Cooperative diversity is a useful technique to increase reliability and throughput of wireless networks. To analyze the performance gain from cooperative diversity, outage capacity is an important figure of merit that captures the inherent diversity-multiplexing trade-off in cooperative diversity schemes. In this paper we derive the outage capacity for(More)
Spread-spectrum systems with large transmission bandwidth present significant challenges from the standpoint of achieving acquisition before the communication commences. This paper investigates a rapid acquisition procedure that exploits multipath to aid the synchronization. In particular, we consider a randomized search strategy and derive the(More)
This paper investigates important properties of acquisition receivers that employ commonly used serial-search strategies. In particular, we focus on the properties of the mean acquisition time (MAT) for wide bandwidth signals in dense multipath channels. We show that a lower bound of the MAT over all possible search strategies is the solution to an integer(More)
A cognitive radio can sense its environment and adapt some of its features, such as carrier frequency, transmission bandwidth, transmission power, and modulation, thus allowing dynamic reuse of the available spectrum. Due to their high degree of adaptability to environmental variations, cognitive radios are expected to utilize packet-based transmission with(More)
by Watcharapan Suwansantisuk B.S., Electrical and Computer Engineering B.S., Computer Science Carnegie Mellon University (2002) Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY May(More)