Placement of rechargeable routers based on proportional fairness in green mesh networks

Nowadays, the fast development of wireless mesh networks have led to a significant growth of energy consumption. Green mesh networks consisting of rechargeable routers supplied by renewable energy sources such as solar power have become a cost-effective alternative solution. In this paper, we study the rechargeable router placement problem and formulate it as an optimization problem to minimize the number of deployed routers while ensuring system Quality of Service (QoS) constraints, including users´ traffic demand, routers´ energy consumption, network failure rate and traffic fairness among users. To assign users to appropriate routers, we first propose two cell association algorithms, namely, Nearest Cell Association Algorithm (NCA) and Proportional Fairness cell Association Algorithm (PFCA). The former only considers the system level efficiency, which may cause unfairness among different users. The later tries to achieve a balance between the network performance and the user fairness. We then design two heuristic placement algorithms embedded with the proposed cell association methods to find approximate solutions for the rechargeable router placement problem. Simulation results show that compared with the optimal placement achieved by exhaustive search, ours can achieve good performance while with greatly reduced computation complexity. Furthermore, the proposed PFCA algorithm can guarantee user fairness with a increase of placement cost.