Study On Space-Time Coding Based On Spatial Fading Correlation Channel

Space-Time Coding (STC) technology, which is mainly utilized for downlink transmission, has become an attractive realm of wireless communications in recent years. It can not only greatly increase the capacity of wireless communications systems but also provide diversity gain and coding gain. The bandwidth efficiency of STC is much more than that of traditional single-antenna systems. It will find its applications in future wireless communications systems for high speed data transmission.Current works on Space-Time Coding have a fundamental assumption that different wireless channels are uncorrelated with each other, but this assumption does not hold for the most real communication channels. Signals from different antennas have some correlations in space due to the insufficient antenna spacing or lack of scattering. This thesis is just based on the wireless channels with spatial fading correlation, the primary contents of this thesis can be summarized as follows:1. The impact of spatial fading correlation on the performance of Space-Time Block Coding (STBC) is studied. The emphasis is put on the impacts of the antenna separation and correlation coefficient on Symbol Error Rate (SER) of STBC. The closed-form of the solution to SER is derived and verified by simulations.2. The performance of the system concatenating eigenbeamforming and STBC, which is extended to the model of precoding, is studied. The performance of the concatenation scheme is theoretically analyzed with the expression of Pairwise Error Probability (PEP) and tested by computational simulations.3. A novel nested STBC with eigenbeamforming is proposed for lager number of transmit antennas. Each group of antennas is weighted by eigenvectors and different eigenbeams are formed to carry Space-Time Block codes, then the preliminary simulations and analysis are performed.