Comparative Analysis of Pilot-Assisted Distributed Cophasing Approaches in Wireless Sensor Networks

Chaythanya, Krishna K and Annavajjala, Ramesh and Murthy, Chandra R (2011) Comparative Analysis of Pilot-Assisted Distributed Cophasing Approaches in Wireless Sensor Networks. In: IEEE Transactions on Signal Processing, 59 (8). pp. 3722-3737.

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Abstract

This paper compares and analyzes the performance of distributed cophasing techniques for uplink transmission over wireless sensor networks. We focus on a time-division duplexing approach, and exploit the channel reciprocity to reduce the channel feedback requirement. We consider periodic broadcast of known pilot symbols by the fusion center (FC), and maximum likelihood estimation of the channel by the sensor nodes for the subsequent uplink cophasing transmission. We assume carrier and phase synchronization across the participating nodes for analytical tractability. We study binary signaling over frequency-flat fading channels, and quantify the system performance such as the expected gains in the received signal-to-noise ratio (SNR) and the average probability of error at the FC, as a function of the number of sensor nodes and the pilot overhead. Our results show that a modest amount of accumulated pilot SNR is sufficient to realize a large fraction of the maximum possible beamforming gain. We also investigate the performance gains obtained by censoring transmission at the sensors based on the estimated channel state, and the benefits obtained by using maximum ratio transmission (MRT) and truncated channel inversion (TCI) at the sensors in addition to cophasing transmission. Simulation results corroborate the theoretical expressions and show the relative performance benefits offered by the various schemes.

Item Type:	Journal Article
Publication:	IEEE Transactions on Signal Processing
Publisher:	IEEE
Additional Information:	Copyright 2011 IEEE. Personal use of this material is permitted.However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Channel reciprocity;distributed cophasing;phase estimation errors;limited feedback;sensor censoring;channel inversion
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	30 Aug 2011 05:29
Last Modified:	30 Aug 2011 05:29
URI:	http://eprints.iisc.ac.in/id/eprint/40332

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