Impact of Relays on LTE-Advanced Performance

This paper studies the performance and coverage improvements introduced by relay deployment in LTE-Advanced systems. Different relay deployment strategies are investigated, namely, amplify-and-forward (AF) repeaters and decode-and-forward (DF) relays (orthogonal and non-orthogonal modes). First, the expressions of peak throughput (i.e., assuming allocate all resources in a cell to one user) for different relay deployment strategies are derived. Next, the calculation of resource partition between e-Node B (eNB) and relay nodes for the repeater and relay scenarios are detailed. A capacity evaluation method for relay deployment is then proposed; this includes the analysis of user-perceived Quality of Service (QoS) based on cell traffic. In addition, we investigate a more advanced adaptive resource sharing strategy for more efficient resource utilization among relays in a cell. Finally, the performances of the different relay deployment strategies are compared using simulation results.