Research On Precoding For MIMO Relay Systems

MIMO (Multi-Input and Multi-Output) and relay technology have become the key technologies in future development of wireless communication systems. The MIMO relay systems are the systems which effective fusion of two kinds of technology advantage. Precoding technology was wildly used in MIMO relay systems and has been a hot area of research for several years.Precoding technology generally divided into two categories:linear precoding and non-linear precoding. Linear precoding has simple structure, but it can’t to develop potential of channel. Non-linear precoding, like THP (Tomlinson-Harashima Precoding) can approach the upper bound of MIMO relay systems capacity. And THP scheme has guaranteed the performance and lower complexity.Good performance of the systems with precoding technology based on perfect Channel State Information (CSI).But in actual communication systems, the sending side has perfect CSI will be very difficult. The limited feedback precoding scheme was used more and more widely.The existing research on precoding technology in MIMO relay systems were based on linear relay, and there have been few studies done on non-linear relay precoding. In this dissertation, a new kind of non-linear relay precoding scheme was proposed. The new scheme with linear source and Tomlinson-Harashima relay (LT relay system). And then, a new kind of codebook was proposed based on Lloyd Algorithm (Constant Amplitude Lloyd Codebook, CAL).