Browsing by Author "Fikre, Zelalem"

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    Performance Comparison of Spatial Multiplexing and Spatial Diversity in Rate Adaptive Wireless MIMO Systems
    (Addis Ababa University, 2007-06) Fikre, Zelalem; Ayele, Hailu (PhD)
    Multiple antenna systems are known to provide spatial diversity and spatial multiplexing advantages in constructing a reliable and spectrally efficient communication link. In spatial diversity scheme the same message or replica of the same message is transmitted from the number of transmit antennas in such a way that at least one of transmitted messages reaches the receiver with out error. In this scheme the main objective is reduction in the probability of error. Unlike spatial diversity, in spatial multiplexing scheme different messages are transmitted from each of the transmit antennas so that the rate of data transfer between the transmitter and receiver is increased. As far as practical system is concerned it needs to have both advantages in order to have a high data rate link with low probability of error. In this thesis by adaptively varying the modulation order of the spatial diversity and spatial multiplexing systems both advantages are obtained for an application with a certain error rate performance requirement. The simulation result has shown that the spatial multiplexing system has a higher throughput at high SNR values as compared to the spatial diversity system. At low SNR values, it is the spatial diversity system that results in high throughput. The ML detection of spatial diversity system has less computational complexity as compared to ML detection spatial multiplexing scheme. Keywords: Spatial Diversity, Spatial Multiplexing, Maximum Likelihood Detection, Space Time Coding, D-Blast and V-Blast