Space-time Block Codes Blind Identification

Blind recognition of communication parameters is a research topic of high importance for both military and civilian communication systems. Along with the development of the MIMO system, blind recognition of communication parameters in the MIMO systems has become a new challenge. Numerous studies about carrier frequency estimation, modulation recognition as well as channel identification are available in literature, but the blind recognition of the space-time block coding (STBC) is a emerging topic in the MIMO communication systems.The blind recognition of STBC provide the basis of STBC decoding. This research has important significance. This thesis studies blind recognition of STBC in non-cooperation communication, the main work is as follows:(1) This thesis introduces the basic model and key technology of the MIMO communication system, analyses the complex working environment that bring frequency selectivity and time selectivity to the channal, analyzes data transfer rates on the theoretical advantage of MIMO systems, namely channel capacity. This thesis introduce the basic principles of diversity techniques. In order to achieve spatial diversity MIMO system introduces space-time coding. This thesis introduces the space-time code criteria, and space-time block code design method.(2) This thesis complete the pretreatment of blind recognition of the space-time block codes, namely the estimation of the transmit antennas and space-time block codes detection. This thesis introduces four methods of transmit antennas estimating, and analyzes the advantages and disadvantages of each method by simulation. The simulation shows the algorithm performance with the SNR, receive antennas number and sampling points of change.The STBC type of communication is unknown to the non-cooperation communication, in order to determine whether communication using STBC, we must do STBC detection first, we propose a higher order cyclostationarity based statistical test to detect space-time block codes, and the simulation shows the algorithm performance with the SNR and sampling points of change.(3) This thesis introduces three methods of blind recognition of STBC based on maxinum likelihood and two methods based on space-time correlation matrices. Different recognition methods are given the appropriate signal model, theoretical analysis and the specific processes of the blind recognition. The simulation experiments compare the advantages and disadvantages of each algorithm in computing, prior conditions and identifying performance, and gives corresponding conclusions. The simulation experiment shows the performance of the algorithm with the number of receiving antennas, SNR and sampling data length of change.