Massive MIMO Using Full-Rate QOSTBC for Higher Capacity Wireless Transmission Systems

Abstract

Abstract The wireless industry has recently been introduced with a technology known as massive Multiple-Input Multiple-Output (massive MIMO) to minimize errors, to maximize performance, energy and spectral efficiency, to increase robustness and link reliability and to enhance data rates. This is implemented by using massive number of multiple transmit and receive antennas, as well as by applying quasi-orthogonal space-time block code (QOSTBC) techniques. The advanced research area in the field of wireless communication system is to place more and more antennas either at the base station or mobile station or both sides of the communication system in order to achieve huge spectral effectiveness comparable to the conventional MIMO systems. The conventional MIMO systems have certain limitations including comparatively low achievable data rates using the transmitter with a maximum of 4 antennas, low spectral effectiveness, and less potential for large spatial dimensions. This thesis deals with massive MIMO system performance employing the QOSTBC scheme with multiple antennas up to 128×128 configuration. The QOSTBC scheme has many advantages in terms of the higher transmission rates and lower decoding complexity. It is an important transmit diversity scheme for more than 2 transmit antennas. The antenna array configurations are classified into 2×2, 4×4, 8×8, 16×16, 32×32, 64×64 and 128×128 massive MIMO systems, which directly affect the system performance. The channel vectors are quasi orthogonal, and the interference is then reduced significantly. The users of this technology can benefit from the improved data rates while using the same frequency resource simultaneously. We present that the BER performance improves with increasing number of antennas. Simulation results verify that the massive MIMO systems with QOSTBC can enhance performance to a full rate, as compared with other massive MIMO systems. We provide simulation results demonstrating the performance for up to 128 transmitter and receiver antennas with BPSK, QPSK, 8PSK and 16QAM modulation formats. The simulation results show how multiple transmit antennas with QOSTBC can lead to outstanding performance over additive white Gaussian noise (AWGN) and Rayleigh fading channels.