Resource Allocation in 802.16j Multi-Hop Relay Systems with the User Resource Fairness Constraint

IEEE 802.16j multi-hop relay task standard defines two mutually exclusive options: transparent relay systems (T-RS) and non-transparent relay systems (NT-RS). In this work, we compare the two relay systems in term of system capacity under user resource fairness constraint. We jointly study the effect of resource allocation and user association rule for maximizing the system capacity, where the user association rule determines the access station for each user. Different system configurations are compared, including: single-input single-output or multi-input multi-output in the relay links between base stations and relay stations, and different number of relay stations in a sector. Simulation results show that the highest capacity is achieved by the NT-RS with 3 relay stations per sector in distributed scheduling mode. Two simple user association rules, highest modulation-and-coding-scheme (MCS) and highest modified effective-spectrum-efficiency (ESE) scheme, are compared along with the optimal rules that maximize system capacity. It is demonstrated that highest (Mod) ESE scheme achieves system capacity close to the optimal rules´.