Resource Sharing in LTE-Advanced Relay Networks: Uplink System Performance Analysis

Relay enhanced networks are expected to fulfill the demanding coverage and capacity requirements in a cost-efficient way. Type 1 inband relaying has been standardized as an integral part of 3rd Generation Partnership Project (3GPP) Long Term Evolution Release 10 and beyond (LTE-Advanced). This type of relay nodes (RNs) supports a relaying mode where the relay link transmission is time-division multiplexed with the access link transmission, whereas macro users share the same resources with the relays. Hence, system performance depends strongly on the resource sharing strategy among and within the links. Further, the set of subframes assigned for the backhaul transmission is semi-statically configured and thus a dynamic reconfiguration to adapt to fast-changing system conditions, e.g. relay cell load, is not viable. Besides, in order to fully exploit the benefits of relaying, the inter-cell interference, which is increased due to the presence of RNs, should be limited via a proper power control (PC) scheme on each link. Therefore, an optimization of both the resource sharing and PC strategy is required to enhance the overall performance of relay networks. In order to tackle these issues, we employ a statistic-based over-provisioned backhaul (Un) subframe allocation to be utilized for flexible co-scheduling of relays and macro users at the donor evolved Node B (eNB). In addition, we propose a combination of relay scheduling based on the number of relay-served users and user throughput (TP) throttling achieving max-min fairness. Performance analysis of various resource sharing techniques along with PC optimization is then carried out within the LTE-Advanced uplink (UL) framework in urban and suburban scenarios. Comprehensive results show that the proposed schemes achieve significant throughput gains and high system fairness with substantially increased flexibility in resource allocation.?