The Research Of Space-Time Block Codes With Partial Feedback In MIMO Systems

In the rapid development of modern wireless communication, traditional Single Input and Single Output system cannot meet people's demand of integrating various multimedia operations, such as voice, video, data and so on, because of the limit of frequency source, the complication of wireless communication, and other infections. Multiple-Input and Multiple-Output system (MIMO) introduces multi-transmit antennas and multi-receive antennas. It can improve the capability and performance of wireless communication system, and increase bandwidth efficiency and transmission rate, without adding bandwidth. It will be one of the key technologies in the coming wireless mobile communication system.Space-Time block codes (STBC) have the simplest construction, the lowest decoding complexity, and the most extensive application in various coding technologies used for multi-antennas transmission. On the base of traditional STBC, the main research work of this paper is to discuss Quasi-orthogonal STBC. It also provides the encoding and decoding algorithms of introducing partial feedback to transmitters, with performance comparing in theory and simulation. The STBC discussed in this paper is at below:(1) Quasi-orthogonal Space-Time Block Codes: At the expense of reducing diversity gain and increasing decoding complexity, quasi-orthogonal codes can increase transmission rate apparently. This paper focuses on Jafarkhani's design, and a lot of simulation has been done.(2) (Quasi-)Orthogonal Space-Time Block Codes with Partial Feedback: Most of STBC are designed without transmitters' knowing CSI. If the transmitters can get them, the performance can be improved accordingly. However, getting all of the CSI needs plenty of feedback and independent feedback channels, so that the transmission rate will be reduced unexpectedly. In practice, only partial CSI is allowed to return to the transmitters, in order to save the bandwidth. Two designs, power weight feedback and phase feedback, are introduced in this paper. Quasi-orthogonal STBC and phase feedback are combined, which can contribute to system performance.