الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
MIMO system is used to overcome the fading problem of wireless communication by sending the same signals on independent paths and the receiver can decode the received signals correctly. In a mobile station, a space-time code is applied to achieve the best performance. Full rate OSTBC is presented for four-time slots and two transmit antennas. This code achieves full diversity, MDV, and determinant criterion. Moreover, a simple and linear decoding can be used to decode the transmitted symbols. The performance of the proposed code is better than the performance of the Double Aalamouti code and Norouzi code. So, the proposed code can be used for uplink transmission for four-time slots.
MIMO-OFDM system improves the diversity gain by adding frequency diversity. OSTBCs for MIMO-OFDM system are proposed. The BER performance of proposed codes is better than the BER performance of OSTBC of Alamouti code. The performance of OSTBCs without beamforming and OSTBCs with beamforming is evaluated. OSTBCs with beamforming improve the performance of the system. Also, two STFCs with and without beamforming have been presented. The performance of proposed codes is better than the performance of Shrivastava code. The STFCs code with beamforming give better diversity gain than STFCs without beamforming. Finally, the BER performance of STFCs with beamforming is better than the performance of STBCs with beamforming.
Complex OSTBC for a large-MIMO system is presented. It is shown that the large MIMO systems, e.g. 16 x 16 and 16 x 32 systems, have very high transmission reliability as they are able to transmit signals with lower BER even when the SNR is less than 0 dB, while maintaining their simple detection and full diversity. It is also found that the code rate of transmission code and the number of receive antennas have an impact on the BER performance of the system. In general, the complex matrix that has lower rate has better BER performance. Also, the use of a high number of receivers can result in superior BER performance achievement. Finally, there is an algorithm to generate complex OSTBC matrix for a large-MIMO system up to twenty-one antennas.