Matched filtering with rate back-off for low complexity communications in very large delay spread channels

Majid Emami*, Mai Vu, Jan Hansen, Arogyaswami Paulraj, George Papanicolaou

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


We study the possibility to transmit data over channels with large delay spreads under the constraint of a very simple receiver which has only one tap. Such a scheme is of interest when a cost-efficient way to transmit potentially high data rates are sought after. We investigate the performance of the optimal prefilter for this scheme and compare it to a simplified, so-called time-reversal (TR) prefilter which has very low complexity. At low SNRs, the TR prefilter and the optimal prefilter are equivalent. At high SNRs, the TR prefilter achieves a performance that is independent from the delay spread of the channel and hence its performance is the same for any bandwidth. In applications where bandwidth is abundant, such as ultra-wide band (UWB) communications, any required performance can be obtained by TR prefilters with a rate back-off transmission (i.e. transmission rate lower than the allowable bandwidth). Similar performance can also be obtained with full-rate transmission using several transmit antennas. This performance is guaranteed, since the high diversity of the large delay spread channel effectively eliminates any fading.
Original languageEnglish
Title of host publicationConference Record of the Thirty-Eighth Asilomar Conference on Signals, Systems and Computers, 2004
Publication statusPublished - 7 Nov 2004
Externally publishedYes
Event38th Asilomar Conference on Signals, Systems and Computers: ACSSC 2004 - Pacific Grove, United States
Duration: 7 Nov 200410 Nov 2004


Conference38th Asilomar Conference on Signals, Systems and Computers
Abbreviated titleACSSC 2004
Country/TerritoryUnited States
CityPacific Grove

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