Performance Evaluation of QO-STBC Encoded MIMO System with D-QR Decomposition Under TWDP Wireless Fading Channel

Abstract

In the recent years, there has been swift development in remote wireless communications. With the expanding count of users and bounded bandwidth available, operators are making a decent attempt to upgrade the network for larger capacity and enhanced quality coverage. Point-to-point remote transmissions through numerous transmit and receive antennas, or the purported Multi-Input Multi-Output (MIMO) channels have gotten extensive consideration amid the previous decade because of its demonstrated capacity improvement over the regular single-antenna frameworks. The expanding necessities on data rate and quality of service for remote wireless communication frameworks convene for new systems to enhance spectrum efficiency and to ameliorate the link reliability. The utilization of numerous antennas at either ends of a wireless link guarantees substantial advancements in terms of spectral efficiency and link reliability. This technology is recognized as MIMO. In the starting, MIMO technology was expected for the point to point communication frameworks. However, with the headway of the innovation, a few impediments too came into notice such as the throughput capability and sort of fading channel. So, this technology was further merged with the Space Time Block Codes (STBC) and other higher order forms of STBCs comprising complex symbol terms in their code structure, such as Quasi Orthogonal STBC (QO-STBC) which is widely famous for attaining full rate but having the disadvantage of less diversity gain and more decoding complexity. In this thesis, D-QR decomposed QO-STBC based MIMO system has been proposed. The comparison amid conventional QO-STBC and proposed D-QR decomposed QO-STBC has been presented. It is observed that at 10-4 BER, conventional system has approximately 22 dB SNR whilst proposed QO-STBC D-QR system has 3 dB. So an improvement of 19 dB is achieved. This is because we get an interference free channel matrix because of D-QR decomposition. Further, QO-STBC D-QR system is analysed for M-PSK and M-QAM schemes with M = 8, 16, 32, 64, 128, 256, 512 and 1024. In case of M-PSK modulation, 8-PSK shows 2 dB, 16-PSK shows 7 dB, 32-PSK shows 15 dB at 10-2 BER and likewise 1024-PSK shows 25 dB SNR at 10-0.2 BER whilst for M-QAM modulation format, 8-QAM shows 0.5dB, 16-QAM shows 4dB, 32-QAM shows 7db at 10-2 BER and likewise 1024-PSK shows 22 dB SNR at 10-2 BER. So, QO-STBC encoded MIMO system with QR decomposition is going to play an important role in the communication field in this era.