Coverage and reliability analysis of multi-IRS-aided distributed space-time block coding in MISO wireless communication systems

Intelligent reflecting surface (IRS) can realize information manipulation and signal modulations to perform space-time coding wireless communication. This article introduces a novel model to perform space-time block coding (STBC), where the base station transmits multiple symbols to a destination through multiple IRS that are utilized to adjust the phase shift and establish strong links. To maximize the end-to-end SNR, we propose a graph theory based method to obtain the optimal transmit antenna selection (TAS) scheme. Based the optimal TAS scheme, we derive the statistical characterizations of the sum of independent generalized gamma random variables to obtain end-to-end signal-to-noise ratio expressions. Then, the closed-form expressions of outage probability (OP) and symbol error rate (SER) are formulated respectively to evaluate the coverage and reliability performance in wireless communication systems. Furthermore, the asymptotic expressions for OP and SER at a high transmission power are given, then the diversity order is discussed to observe the performance limit. To verify this theoretical performance analysis, extensive computer simulations are conducted to prove its effectiveness. The simulation results show that the multi-IRS-aided STBC system can attain the same or even better performance as the STBC system based on multiple amplify-and-forward relays using a little number of reflecting elements. More interestingly, the OP and SER of this system decrease more than that of the relays-aided system as transmission power increases.