Design of relay distances for multihop WiMAX systems based on Bit Error Rate consideration

WiMAX is an IEEE802.16 standard that provides a high speed transmission with wide coverage range. In IEEE 802.16j, the multiple Relay Stations (RS) are added to employ multihop links for WiMAX systems to extend coverage range and capacity. Many works in literature concern the RS locations based on the effective cost and the optimum user capacity. Most of them assumed the lossless transmission between RS and Base Station (BS). Consequently, the distance between RS and BS has no effect on locating RS. However, the real performance of WiMAX signals has to take the physical link between RS and BS into account. Therefore, this paper proposes the design of suitable RS distances to provide the required Bit Error Rate (BER) in coverage range. The results indicate the importance of designing relay distances. Also this paper reveals the method to design the suitable RS location under BER consideration.