This paper investigates the system performances of the IEEE 802.16j system with mobile relays such as cell throughput and service coverage. It also focuses on resource management problems such as overlapped subchannel allocation (OVSA) and orthogonal subchannel allocation (ORSA) and relay power control such as simplified on-off mobile relay control (SOMRC). The performance of the proposed schemes is evaluated with both proportional fair (PF) and mobility assisted opportunistic scheduling (MAOS)  schedulers. Simulation results show that the cell throughputs of the proposed schemes are greater than one without relay, and the cell throughput of OVSA scheme is improved with increasing the number of mobile relay stations (MRSs). OVSA with SOMRC also provides larger cell throughput than OVSA without MRS power control. The service coverage of ORSA scheme is greater than one of OVSA scheme, and OVSA with SOMRC offers expanded service coverage than OVSA without MRS power control.