| Multiple-Input Multiple-Output (MIMO) technology can efficiently increase channel capacity and improve the bit error rate (BER) performance by setting multiple antennas for sending and receiving signal at the transmitter and receiver without increasing the system bandwidth or transmit power. As a key technology for MIMO system, spatial modulation can improve the BER performance greatly while keeping high spectral efficiency and low complexity; therefore, it overcomes the disadvantages of spatial diversity with low rate and spatial multiplexing with high complexity of traditional MIMO technologies.Firstly, based on the radio channel fading characteristics, the channel propagation models of MIMO system are analyzed, then spatial diversity and spatial multiplexing are studied briefly through taking the Alamouti and Vertical Bell Labs layered space-time structure (V-BLAST) for example in this thesis. Secondly, several original modulation techniques are investigated and the performance is simulated. Thirdly, some demodulation algorithms and mapping schemes about spatial modulation are focused and their performance is validated by simulation. Finally, two high rate and good BER performance modulation schemes, i.e. pairs mapping spatial modulation (PMSM) and block mapping spatial modulation (BMSM) are proposed in order to improve the transmit rate of SM technique. The corresponding detection algorithms and complexities are analyzed, respectively. For different channel cases, the results of simulation prove two proposed schemes are with more excellent BER performance than traditional spatial modulation and MIMO technologies. Furthermore, the BMSM scheme and antenna selection technique are combined at the transmitter in this thesis for the purpose of enhancing the BER performance, and good behavior is verified in the actual MIMO multi-polarization channel. |
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