Signal Transmit-Processing Technology Research For TDD Systems

For TDD-CDMA system, utilized the reciprocity of the channel uplink and downlink, the speed of available data and the system capacity can be improved for the downlink of TDD system, the channel estimation and the data detection can also be avoided, the complexity and the cost of mobile station can be reduced. Joint transmission(JT) technology and Pre-Rake technology are all receiver orientation technology, called signal transmit-processing(STP) technology.This paper focused on joint transmission technology based on multi-user MIMO-OFDM, and investigated signal transmit-processing technology based on multi-user MISO-OFDM and multi-user MIMO-OFDM.A scheme of joint transmission based on multi-user MIMO-OFDM was proposed in this paper after the deep research to multi-user JT MIMO. The system model and algorithm of the data transmission and detection were developed based on this scheme. The receiver algorithms were priori chosen,whereas the algorithms to be used at transmitter have to be a posteriori adapted under consideration of channel state information and the receiver algorithms.The receiver's calculative cost for multi-user MIMO-OFDM downlink was reduced with this scheme, the performance and capacity of the system were also improved. The results of the simulation in the TDD system were presented, which indicated the superiority of the multi-user JT MIMO-OFDM and its bright future.Two schemes of signal transmit-processing technology based on multi-user MISO-OFDM and multi-user MIMO-OFDM were proposed in this paper after the deep research to multi-user MISO STP. System models were builded, and both of the algorithms of the data transmission and detection were developed according as these models. The results of the simulation in the TDD system indicated that multi-user STP has advantage on increasing Bit Error Rate (BER) performance of system and reducing the complexity and cost of mobile station.