Site planning of Relay Stations in greenwireless access networks: A genetic algorithm approach

The relay-based wireless access networks are envisioned as one of the most promising “green” network architectures, in which Relay Stations (RSs) are incorporated to meet the fast-growing throughput requirement of Subscriber Stations (SSs) by exploiting the performance benefits of cooperative relay technology. Due to the lower cost, less energy consumption and CO₂ emission of RSs comparing with those of Base Stations (BSs), the relay-based wireless access networks are also appealing to infrastructure operators. In this paper, we focus on the problem of RS site planning, which is a critical task of network planning and deployment to achieve an efficient and scalable network environment. An optimization framework is developed to minimize the total cost of RSs as well as meet the minimal traffic demand for each SS. The problem of joint RS placement and bandwidth allocation is formulated into an mixed integer nonlinear program. We resort to an improved Genetic Algorithm (GA) in order to yield optimal or near-optimal solutions. Simulation results show that our approach is fairly effective and robust to different scenarios of the RS site planning problem.