Delay guaranteed VoD services over group-based integrated fiber-wireless (FiWi) access networks with energy efficiency

In group-based fiber-wireless (FiWi) access networks, where wireless clients are divided into several groups according to their interested Internet services, VoD services will meet new challenges considering the diversity of video requesting probability for each wireless group. In this paper, we categorize wireless groups into "video-hot" group with great interest in VoD services and "video-cold" group with infrequent video requesting. For video requests from "video-hot" groups, we firstly propose an energy-efficient optical network unit (ONU) selection approach to reduce ONU power consumption by selecting a subset of ONUs to support such requests, then our previously proposed rebroadcast and patching scheme can be effectively applied. For video requests from "video-cold" groups, a batched multicasting scheme is presented for energy and bandwidth saving. Both of the VoD schemes mentioned in this study are with the aim to minimize worst-case playback delay (WPD) which is particularly important as Internet users. In view of that some ONUs may need to handle video requests from two kinds of group, optimal ONU channel assignment aims to minimize weighted overall WPD is also studied. The efficiency of the work is finally demonstrated by the simulations. (C) 2015 Elsevier Inc. All rights reserved.