Capacity comparison of relay-assisted schemes with and without direct path

Abstract

In this paper we analyse two different VMIMO schemes: In the first one we consider 2 relays nodes employing a distributed space-time block coding and in the second one just a single relay node is considered. For the first approach we also investigate the impact on the system performance when the direct path (between source and destination) is considered. We assume that all communication nodes are equipped with single antenna. Two types of relay protocols are considered: Equalize-and-Forward and Amplify-and-Forward. The instantaneous normalized capacity for these schemes is derived and outage capacities are compared with a colocated MISO and conventional SISO systems, considering different propagation scenarios. Numerical results have shown that, for some scenarios investigated, VMIMO schemes achieve higher capacity than the colocated MISO system.