Adaptive scheduling for differentiated services in the ethernet passive optical networks

Ethernet Passive Optical Network (EPON) is a technology viewed as an attractive solution to the "last mile" problem. The Interleaved Polling with Adaptive Cycle Time (IPACT) is a remarkable Medium Access Control (MAC) protocol for EPON. There are two aspects within IPACT. One is inter-Optical Network Unit (ONU) scheduling. The other is intra-ONU scheduling. In this paper, we propose a systematic adaptive scheduling scheme to enhance the functions of IPACT on both the inter-ONU scheduling and the intra-ONU scheduling in order to achieve efficient bandwidth utilization of the EPON under unbalanced traffic and to provide Class-of-Service (COS) or differentiated services within an OND. The simulation results show that our proposed scheduling scheme can improve the performance of the EPON system under unbalanced traffic loads and provide fair bandwidth allocation of the uplink to different types of traffic.