On the joint scheduling and intra-cell interference coordination in multi-relay LTE uplink

The relay-assisted Long Term Evaluation (LTE) cellular system is one of the most promising technologies to enhance the throughput and coverage of the access network. Injection of relays in a cell opens many issues of frequency/time domain radio resource allocation and frequency planning. In this paper, we consider the uplink of LTE relay-assisted network and formulate the joint scheduling and intra-cell interference mitigation problem as a non-linear optimization taking into account the projection of the gradient of user´s utility function over the user´s rate vector based on Lagrangian method, then we proposed a novel transformation of scheduling problem into combinatorial Knapsack optimization to convert the optimization problem into binary integer non-linear program. Finally, we illustrate the solution through a low complexity algorithm to allocate resources based on group of subchannels (GoS), while considering the contiguity constraint, which is a crucial feature of LTE uplink. Simulation results show that our proposed scheme is near optimal with a much lower complexity of the order of O(Σ_m^M+1 K_mN_c,_m).