Amplify-and-Forward Relay Networks under Received Power Constraint with Imperfect CSI

The mobility of relay stations within a cell creates an interesting scenario where multiple sources, transmitting correlated data, can co-operate to satisfy power constraints at the receiving node. While beneficial to the receive node, this approach creates un-intended interference for neighboring cells reusing the same frequency. Previously, a relay scheme was proposed to simultaneously maximize SNR and minimize MSE, for an amplify-and-forward (AF) relay network operating under a receive power constraint guaranteeing that the received signal power is bounded to control interference to neighboring cells. In this paper, we investigate the effect of channel uncertainties on system performance. A modified solution for the proposed scheme under imperfect channel state information (CSI) is provided. Furthermore, we investigate the diversity order of the proposed scheme under perfect CSI. Simulations are provided to verify the analysis for both perfect and imperfect CSI assumptions.