Analysis of Image Transmission using MIMO-Alamouti Space-Time Encoding

Rapid increase in requirements of high speed transmission of multi-media information resulted in development of MIMO systems. MIMO systems have emerged as the most efficient methodology for the high speed robust data transmission. In this paper, the performance of Alamouti Space-time block coded MIMO system is analysed using the metric of efficient image transmission over the Rayleigh fading channel. The transmitted image is modulated using M-PSK modulation technique, and its reconstructed version is plotted as an output function. Zero-forcing equalization is done for the detection of the original symbols from the received symbols which are influenced by the multipath fading and the channel noise. The results for image transmission using 2×1 and 2×2 Alamouti STBC are evaluated for different SNR values. The inverse relationship between the SNR and BER in the results depict that the high value of SNR and receiver antenna leads to enhanced system efficiency with reduced BER and distortion less recovery of image. It is very evident from the analysis of the received images that as we increase the SNR or the number of the antennas at the receiving side, the quality of the received image improves for the same channel environment. During the analysis, it is also found that increasing the number of bits forming one symbol in M-PSK modulation increase the BER which is undesirable. Thus, trade-off between the number of antenna, SNR and the M value of PSK is an essential requirement for achieving enhanced performance.