Study Of Multi-input Multi-output Encoding Technique

The Beyond 3rd Generation (B3G) wireless communication system become a new focus after the successful development of the 3rd Generation wireless communication system. Multi-input and Multi-output (MIMO) antenna system must be widely used in the B3G wireless communication system for the raison that it can take off the impress of multipath fading and increase the data transfer rate and spectrum availability. In this paper the basic theory and the encoding scheme of the MIMO system will be studied, and subsequent work of others study will be based on it. First of all, the channel capacity of the MIMO system is discussed. It has a linear growth while the least number of the antennas in transmit system and receive system increases, and it is better than the single-input and single output system or others smart antennas system. Secondly, a few time-space encoding schemes are studied and compared together such as STTC, STBC, BLAST. Thirdly, Alamouti time-space code is studied, and its performance in Rayleigh-fading environments is simulated. From the result it can be proved that the gain of transmit diversity is identical with receive diversity, and the gain of the diversity is profitable to the performance of the system Fourthly, Turbo codes and BLAST coeds is studied whit emphasis. Parts of the Turbo codes are studied and compared. The combined encoding of Turbo codes and BLAST codes viz. Turbo-BLAST encoding is studied, we take an example as two-input and tow-output antennas system, it's performance in Rayleigh-fading environments is simulated and analyzed, From the result we can see that the performance of multi-input and multi-output system which used Turbo-BLAST scheme is much better than the single-input and single-output system and other time-space encoding systems, and its performance is improved while increasing the iterations. So Turbo-BLAST scheme must be widely used in the mobile communication system in the future.