Optimal Relay Station Placement in Broadband Wireless Access Networks

Abstract

With the development of IEEE 802.16j multihop relay protocol, the requirement to enhance the network capacity in a wireless network has been met e ectively. In this thesis, we study the capacity enhancement problem for a broadband wireless access network which is achieved by optimal placement of Relay Stations (RSs) along with the presence of a Base Station (BS) and multiple Candidate Positions (CPs). We present a mixed integer programming formulation for the crucial task of RS placement. Weighted objective is also explored to include preferential RS placement. The proposed formulations are solved in a matter of seconds. It is observed that with preferential RS placement, the same demand can be met with 73% fewer RSs with a slight, 6%, decrease in the overall network capacity. Moving forward, the objective is broadened to combine and include joint BS and RS placements for a given network. This model formulation provides better overall capacity than combined capacities of RS placement formulations. Maximin objective is introduced to distribute the excess bandwidth to all subscriber stations (SS) rather than assigning it to only one SS. With this approach, bandwidth allocated to each SS is increases by an average of 35.18%.