Research On Differential Space Time Coding Technology In Mimo-Ofdm Systems

Multiple-input multiple-output(MIMO) based on multiple antenna array and space time coding(STC) techniques can take full advantage of the trait of wireless channel to improve the system capacity and quality of communications, without increasing the transmitting power and frequency usage, therefore, they has become one of the key technology hotpots of current and future wireless communications. On the other hand, in the broadband orthogonal frequency division multiplexing (OFDM) systems, combining MIMO space time coding and frequency diversity technique can effectively confront frequency-selective multi-path fading, thus realize robust data transmission in broadband channel. Nevertheless, due to the large increase of OFDM sub-carrier numbers and rapid change of channel fading status, the cost of channel estimation becomes so big that it is difficult to use coherent detection for decoding. Differential space time coding can obtain the diversity gain when channel state information is unknown at the receiver. However, among the existing...