Analysis On System Of MIMO And Space-time Codes

With the development of 3G , MIMO has been one of the hotspots in wireless communication field, Which could improve capacity of communication system remarkably by transmiting the data in different space field and time field,but the same frequency field, using more than one antenna in transmitter and receiver. And if using space-time code in MIMO system, the capacity of MIMO system could be made full use nearly, And the error rate could be improved. If space-time code be used in OFDM-MIMO system, the capacity of OFDM-MIMO system could be improvd more. The present paper deals with the technique of MIMO and space-time code which applys to system of MIMO .The paper introduces the system of MIMO firstly, and gives the formula of capacity in several coummunication channels and emulates the essential performance of it, the conclusion of emulation is analysed. Then, the paper gives several factors which effect on the capacitys, and the formula of the capacity with the factors respective. Secondly, the present paper introduces four types of space-time codes. It consist of STBC (Space-Time Block Codes),DSTBC(Differential Space-Time Block Codes),STTC(Space-Time Trellis Codes) and LSTC(Layered Space-Time Codes). Then, this paper gives the principle of encoder and decoder of these space-time codes. The performance of which is emulated using Monte Carlo method. Then, the conclution of emulation is analysed respectively. Lastly, the present paper gives introduction of MIMO-OFDM system, containing of the principle and structure of it. Then, this paper gives the formula of capacity and compare to MIMO system. Then, it emulates the performance of MIMO-OFDM by using STTC as the space-time code of system and analysis the conclusion.