Improving relay selection in cellular networks

To extend and improve the cell coverage, an efficient solution is to place several relay antennas in the cell. Several protocols for relay selection were proposed in the past years. However, the asynchronism between the received signals due to the different locations of the relays was not addressed. In this paper, we propose to select the relays based on several important criteria. The SNR (Signal to Noise Ratio) between the relays and the mobile is first taken into consideration. Then, the delay differences between the different signals arriving to a mobile are computed. This proposed protocol will allow the receiver to choose the relays that verify a certain SNR threshold and delay conditions. Thus, the best relays in terms of SNR and delay are selected for the communication between the base station and a mobile. Moreover, the overall enhancement of the cooperative system performance, in terms of signaling time and error rates, is shown by numerical calculations and simulations.