Study of Low Complexity Multiuser Receiver Design for Space-Time Coded Code Division Multiple Access Systems
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Date
2007-07
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Addis Ababa University
Abstract
The goal for the next generation mobile communication systems based on CDMA is to integrate
a wide variety of communication services such as high speed data, video and multimedia traffic
as well as voice signals. To effect these services, high rate data transmission and reception
techniques are required.
As demands for communication services increase, there is considerable economic benefit in
improving the spectral efficiency of the communication system. One of the proposed approaches
for these high data rate and spectrally efficient transmission in CDMA systems is space-time
coding. The use of space-time coding techniques in CDMA systems increases multiuser
interference. The effect of multiple access interference can be mitigated by using multiuser
receivers. Multiuser receivers in STC CDMA systems have been shown to provide significant
improvements in spectral efficiency. However, despite the great promises, these receivers have
not been widely deployed in commercial communication systems. This lack of commercial
interest is partly because of issues related to receiver complexity.
Thus using analysis, reasonable approximations and simulation, this work attempts to realize a
lower complexity multiuser receiver for STTC DS-CDMA systems. The complexity is reduced
by dividing the users into groups having smaller trellises. The simulation results show that the
proposed receiver performs close to the optimal receiver even at high cross correlations of the
spreading sequences with a reduced complexity.
Keywords: CDMA, Spreading Sequences, Space-Time Coding, Fading Channels, Multiple
Access Interference multiuser detection
Description
Keywords
Cdma, Spreading Sequences, Space-Time Coding, Fading Channels, Multiple Access Interference Multiuser Detection