Research On The Techniques Of MIMO Space Time Coding And Communication System Efficiency

The Multiple Input Multiple Output (MIMO) technology can achieve high data rate in wirelesscommunication by using multiple antenna both at the transmitting and receiving end. Space-timecodes (STC), which are developed after the MIMO technology, are special coding techniques thatcan cooperate with MIMO. By both coding in the time domain and the spatial domain, STC is veryeffective in increasing the transfer data rate over wireless channels, and is considered one of theadvanced coding technologies in MIMO technology.There are generally two main categories of STC, the first of which must get the channel stateinformation (CSI) to work properly and the second of which do not need the knowledge of CSI.The first kind of STC includes layered space-time code, space-time block code and space-timetrellis code while the second kind of STC contain mainly differential space-time code(DSTC) andunitary space-time code(USTC). In this dissertation, more attention is paid to the classic Alamoutispace-time code and two of the second kind of STC which are USTC and differentialUSTC(DUSTC); the main coding and decoding techniques of the three STCs above are discussedand the related simulation results are given to provide a straight forward view of their performance.Another part of this dissertation is about frequency efficiency and power efficiency ofcommunication system. A new concept to measure the efficiency of power use which is called SNR(signal-to-noise ratio) efficiency is put forward as an equivalent concept for power efficiency andwith the new concept, the exact closed form tradeoff mathematic relationship of frequencyefficiency and SNR efficiency for Shannon channel is derived.Moreover, the closed form formula of the bit error rate(BER) as a function of SNR of thedifferential binary phase shift keying(DBPSK) communication system when inter-symbolinterference(ISI) is involved is derived for the first time in literature; the Monte Caro simulationresults are presented to proof the correctness of the derived formula.