Performance analysis of MIMO link under fading channels

In modern wireless communication, multiple-input multiple-output (MIMO) system plays an important role as it improves channel capacity, range and reliability without requiring any additional bandwidth or transmit power. This research presents a detailed analysis of capacity performance of MIMO systems under four fading cases i.e. Gaussian, Weibull, Rayleigh and Nakagami-m fading in the low signal-to-noise ratio (SNR) regime. We first derive analytical expressions for the expectation of the trace of the complex channel matrix. Then we measure the low-SNR performance of MIMO system under four fading conditions with respect to minimum normalized energy per information bit and wideband slope. Also a comparative analysis has been performed between the channel capacity of spatial-multiplexing (SM) MIMO and Orthogonal Space Time block coded (OSTBC) MIMO system. Simulation results show that performance of the system depends on different criteria of MIMO fading channels. According to the capacity performance of MIMO system, four fading channels can be ordered as Gaussian, Nakagami-m, Rayleigh and Weibull fading channels respectively.