Multimedia content delivery through multicast-capable broadband networks.

摘要

Internet protocol television (IPTV) refers to multimedia content services (e.g. television programs, video on demand, audio, graphics, etc.) that are distributed over an Internet protocol (IP) network. IPTV is viewed as the next killer application for the broadband networks due to its flexibility and high bandwidth requirement. Therefore, in the dissertation, we focus on resource-efficient, energy-efficient, secure, and correct multimedia content delivery through broadband optical core and wireless access networks.;We first study multi-class multicast flow aggregation, which takes security into consideration. Given the available network resources, a secure level of each multimedia program, a set of requests for multimedia programs, the objective of our work is to find an approach to the joint optimization of the multi-class multicast flow aggregation and light-tree establishment (MMFA) problem. We model the problem with an aggregation graph as well as an optical transport network graph. We then develop an integer linear programming (ILP) and four heuristics for the MMFA problem. Simulation experiments are carried out to verify the effectiveness of both our ILP model and heuristics.;More often than not, optical networks provide multiple capacities (line rates). When we deliver multimedia content through multiple line rate optical networks, the highest line rate may not always be preferred. The reason is that 1) higher line rates may suffer more impairments than lower line rates; and 2) higher line rate consume higher energy. Therefore, we consider multicast flow aggregation with impairment constraints and with the objective of minimizing the total energy consumption.;We employ a novel graph model for dynamic multicast aggregation and focus on the aggregation problem in optical networks. An on-line aggregation algorithm is developed based on the graph model to achieve various objectives under different aggregation policies.;In this work, we also consider IPTV delivery in a wireless access network to provide "last-mile" transmission from sources to end users. Since end users may have different wireless devices, they may have different display resolution requirements. Current systems provide simulcast for IPTV service in which each base station (BS) broadcasts a program repeatedly over the maximum transmission range, one resolution at a time. This approach is an extremely energy consuming method. Thus, the problem of how to design an energy-efficient simulcast scheme for BSs in a region to guarantee successful communication and QoS is an important problem. We develop an algorithm (named RingCover) and prove that the algorithm can achieve the optimal solution in terms of energy consumption for a single base station. On the other hand, the energy-efficient simulcast for multiple base stations is proved to be NP-hard.