| With the rapid development of wireless communications, the available bandwidth for wireless applications becomes more and more insufficient. Therefore, how to improve data rate without expending bandwidth becomes a main goal in modern communication system design. Recently, two wireless communication schemes, which can be used to effectively combat with multi-path fading, are widely investigated around the world. One is the multiple-input multiple-output (MIMO) technology and another is the orthogonal frequency division multiplexing (OFDM). As a result, a combined system, MIMO-OFDM, can be used for wireless communications to jointly explore the advantages of the above two strategies.In the study of MIMO-OFDM systems, the space-time block codes (STBC) and the space-time trellis codes (STTC) are two efficient coding approaches. The former can be used to offer a full diversity gain, and the later can provide the systems with a large coding gain. Since 2003, super-orthogonal space-time trellis codes (SOSTTC), a new coding method processing the merits of both STBC and STTC, have been developed.In the thesis, a new SOSTTC scheme is proposed for 16QAM constellation which can be used for high speed wireless communications. This approach is then further applied to an MIMO-OFDM system. To examine the performance of the proposed MIMO-OFDM system based on SOSTTC, the one-ring channel model is studied. The core contents of the work are as follows.(1) The one-ring flat channel model for MIMO communications is analyzed and an extended multi-path channel model is proposed, which can match the real wireless communication environment more accurately.(2) A SOSTTC method for 16 QAM signals is suggested.(3) The proposed coding technique and channel model above are future applied to the MIMO-OFDM systems. The performance of the system in different channel environments is investigated by using MATLAB-based simulations... |
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