Performance Evaluation Of Quasi Orthogonal Space -Time Block Code With Beamforming Technique

Abstract

Wireless networks have quickly become part of everyday life, MIMO and Space Time Coding techniques have generated much research interest in recent years. An important class of space-time code is the Orthogonal Space-Time Block Code (O-STBC), which achieves good performance and ability to provide full transmit diversity for mitigating slow fading by requiring multiple antennas only at the base stations or access points. However O-STBC suffers from low code rate when used with more than 2 transmit antennas and complex modulation. In this thesis present Quasi-Orthogonal STBC (QO-STBC), focuses on the design and analysis of full-diversity QO-STBC with very low decoding complexity and high code rate. In this study the performance of Quasi Orthogonal Space Time Block Codes (QOSTBC) with 16QAM and rotated QPSK has been analyzed and compared over the proposed method using the beamforming technique, and analysis of the bit error rate (BER) performance of QOSTBC. This design technique is implemented with two cases of 1, and 4 transmit antennas and 1, and 4 receive antennas. The simulations show that the Quasi Orthogonal STBC design can enhance the performance and results for QOSTBC with the proposed beamforming scheme shows better performance over the 16QAM and rotated QPSK modulation.