Impact of Path Loss on the Capacity of Large MIMO AF Relay Networks

This paper studies the asymptotic capacity of large MIMO amplify-and-forward (AF) relay networks with one source-destination pair equipped with M antennas and K single-antenna relays. In contrast to prior works, we consider not only the multipath fading but also the path loss effect. By using random matrix theory, we first derive the asymptotic eigenvalue distribution (A.E.D.) of the channel covariance matrix between the source and the destination as M and K approach infinity while their ratio remains constant. Based on the resulting A.E.D., the system capacity is then obtained. More specifically, a linear relay distribution is considered to evaluate the asymptotic capacity, which can realistically model the large MIMO AF relay networks. Both theoretical analysis and Mont-Carlo simulations have consistently shown the impact of path loss parameters on the asymptotic capacity.