Integrated BS/ONU Placement in Hybrid EPON-WiMAX Access Networks

Integrated optical and wireless networks are considered as the next generation access networks because of the potential benefits from both technologies. In this paper, we consider the integrated BS/ONU (IBO) placement problem in the hybrid EPON-WiMAX system to efficiently utilize network resources as well as reduce the system cost. We propose a modified clustering algorithm (MCA) to obtain the near-optimal result that minimizes the number of IBOs needed to support all wireless relay BSs residing in the wireless part of the integrated system, while satisfying several necessary quality-of-service (QoS) constraints, e.g., hop count, cluster size, etc. In contrast to the existing related work, our MCA approach forms the clusters starting from the network edge towards its center and the construction of clusters is not only based on the "greedy" idea but also considers the load balance. Simulation and numerical results show that the number of IBOs generated from our algorithm is always less than or equal to the best results known in the current literature, but our algorithm can achieve better network performance in terms of the reduced average transmission delay, lowered link failure probability and more balanced load.