The Full-rate Cooperative Relaying Transmission Scheme Based On Alamouti Space Code

With people’s increasing diverse needs on wireless multimedia, the next generation of wireless communication networks’development must in the trend of more reliable information transfer performance and higher information transfer rate. Therefore, in the face of increasingly tense status of spectrum resource, without sacrificing the extra bandwidth of multiple antenna system becomes one of research hotspots of many scholars. However, volume, energy restriction and other physical conditions of the mobile user terminal has greatly restricted the full application of multiple antenna system. In order to overcome these shortcomings, the cooperative wireless communications system came into being as a multiple antenna technology development.In traditional MIMO(Multiple-Input Multiple-Output) system, the related pre-coding technology research has already been relatively mature, it is a link adaptive technology which has extensive application; Due to the cooperative communication system and the multiple-input multiple-output (MIMO) system has great similarities, so we can introduce pre-coding technology into the cooperative communication system. Generalized pre-coding refers to any pre-process operation in the transmitting terminal, this thesis uses linear complex field coding.In the wireless cooperation communication network, distributed space-time coding can greatly increase the system reliability or effectiveness of mobile communication. It can explore the spatial diversity gain and time diversity between the antennas. In present the research of the distributed space-time coding scheme and key technology in wireless cooperation communication network is already rise, but is still far from in-depth. High reliability, high rate, low detection complexity and low power consumption of the distributed space-time coding scheme has been recognized as a hot and difficult point in the next few years.This thesis is based on cooperative a communications model and analyzes the distributed space-time coding application in different forward models in cooperative communication, the main contents are as follows:(1) Several basic space-time coding are introduced and analyzed, a key scheme which can realize the diversity gain of the system and has a relatively low decoding complexity at the receiving end is researched in detail, namely Alamouti space-time code;(2) Combining the features and advantages of the pre-coding technique and Alamouti space time code, The thesis studied the full-diversity full-rate wireless cooperative relaying transmission schemes in two different forwarding protocol, in which the signal received from source node in the first two time slots coded in Alamouti space-time code’s way;(3) In order to obtain full diversity gain of the distributed wireless systems, enhance the fading ability of signal transmission in the cooperative process of the anti-relay and achieve full rate transmission, these two schemes both use pre-coding technology. Finally, through the simulation and analysis, we can prove that the transmission scheme which proposed in this thesis not only can get a better error performance but also can reduce the detection complexity compared with traditional transmission scheme.