COMPARISON OF PSK AND BPSK MODULATION TECHNIQUES OF MIMO SYSTEM UNDER ALAMOUTI'S SCHEME

摘要

The exploiters of the wireless communication demands for higher data rates, acceptable voice quality with higher network capacity confined due to limited accessibility of radio frequency spectrum, Channel capacity, bandwidth, physical areas and transmission problems caused by different factors like fading and multipath distortion. As in wireless systems it is required to have higher voice quality and high bit rate data services as compared to the present cellular mobile radio standards (up to 2 Mbits/sec). Therefore the key challenge faced by future wireless communication systems is to provide high quality of service (Qos) i.e high data rate wireless access. There are many performance abjection factors in wireless communication channels but FADING problem is the leading worsening problem. In this paper, we studied various transmit diversity techniques in multiple-input multiple-output (MIMO) wireless communication systems. In wireless communication fading of channels is the serious cause of the received degraded signals.. Alamouti proposed a remarkable diversity scheme in utilizing both space and time diversity known as space time coding, using two transmitter antennas and one receiver antenna the scheme provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmitter antenna, and two receiver antennas. It includes overview of the MIMO system, description of the diversity, overview of Maximum Ratio Combining, Alamouti's Transmit Diversity Scheme, simulation results are presented with major conclusions of the research.