Hybrid radio resource allocation and interference coordination for type 1a-relayed long term evolution uplink

Relay technology has been included in long term evolution (LTE) cellular system through 3GPP Release 10. Relay-based LTE cellular system is one of the most promising technologies to enhance the throughput and coverage of access network. Deployment of relays in a cell opens many issues of frequency/time domain radio resource allocation and frequency planning. In this study, the authors consider the uplink of LTE relay-assisted network and formulate the joint scheduling and intra-cell interference mitigation as a non-linear optimisation problem. They take into account the projection of the gradient of user´s utility function over the user´s rate vector based on Lagrangian method. They propose a novel transformation of scheduling problem into combinatorial Knapsack optimisation to convert the optimisation problem into binary integer non-linear program. Finally, they present an alternate solution through a low complexity algorithm to allocate resources based on group of resource blocks, whereas considering the contiguity constraint. Simulation results show that the proposed scheme is near optimal with a much lower complexity order.