Optimal Relay Station Placement in Next-Generation Relay-based Broadband Wireless Access Networks

To satisfy the stringent requirement of capacity enhancement in wireless networks, cooperative relaying is envisioned as one of the most effective solutions. In this paper, we study the capacity enhancement problem by way of Relay Stations (RSs) placemen to achieve an efficient and scalable design in nextgeneration relay-based broadband wireless access networks. To fully exploiting the performance benefits of cooperative relaying, we develop an optimization framework to maximize the capacity as well as meet the minimal traffic demand for each Subscriber Station (SS). The problem of joint RS placement and bandwidth allocation is formulated into an mixed integer nonlinear program. We reformulate it into an integer linear program which is solvable by CPLEX. To avoid exponential computation time, a heuristic algorithm is proposed to efficiently solve the formulated problem. Numerical analysis is conducted through case studies to demonstrate the performance gain of cooperative relaying and the comparison between the proposed heuristic algorithm against the optimal solutions.