This thesis studies multicasting high bandwidth media traffic in wireless mesh networks (WMNs). Traditional multicast methods use a single multicast tree to reach all destinations, and adapt the multicast rate to the destination with the worst path quality. This approach does not fully utilize the network resources nor distinguish the quality of service (QoS) requirements of different users. It also penalizes the users having better path quality and requiring higher QoS. In multi-hop transmissions, the end-to-end transmission rate is limited by the link with the worst transmission conditions. This makes it difficult to multicast high-bandwidth media traffic with good quality. Using multiple description coding (MDC), the source traffic can be split into multiple sub-streams, referred to as descriptions, each of which requires a much lower bandwidth and can be transmitted along separate paths. In this thesis, we study routing and QoS provisioning jointly for multicasting multiple description (MD) encoded media traffic in WMNs. Routing for the multiple descriptions is jointly studied, while considering the channel quality of different links in the network and QoS at individual destinations. The work in this thesis is divided into two parts.
The first part (Chapters 3 and 4) considers balanced descriptions, each of which contributes equally to the quality of the recovered media at a destination, and we study the problem of power efficient multicasting for the MD-encoded media traffic in WMNs. In Chapter 3, single-hop transmissions are considered. That is, the access points (APs) that store the source traffic communicate with the destination nodes directly. We study two problems jointly, description assignments and power allocations. The former is to assign a description for each AP to transmit, and the latter is to allocate the transmission power for the APs. Different power efficiency objectives are considered, subject to satisfying the QoS requirements of the destination nodes. For each objective, an optimization problem is formulated and heuristic solutions are proposed. Chapter 4 extends the work to multi-hop transmissions, where relay stations (RSs) are available to forward the traffic from the APs to the destinations. We consider two different routing structures based on whether an RS is allowed to forward more than one description. The objective is to minimize the total transmission power of the APs and the RSs in the network, subject to the QoS requirements of the destinations. An optimum problem is formulated and then translated to an integer and linear programming problem, and a centralized scheme with much lower complexity is proposed. Following that, a distributed scheme, referred to as minimum weight k-path scheme, is proposed, which builds one multicast tree for each description. By permitting only neighboring nodes to exchange related information, the scheme allows each node to find its best parent node based on the additional transmission power needed to establish the link.
The second part (Chapter 5) of the thesis considers unbalanced descriptions. Routing for the multiple descriptions is jointly considered with application layer performance, so that the maximum distortion of recovered media at the destinations is minimized. An optimization problem is first formulated, and a centralized scheme with lower complexity is proposed. The centralized scheme first finds a set of candidate paths for each destination based on a predefined set of criteria, then it iteratively expands the multicast trees by only merging the paths that minimize the maximum distortion for all destinations. A distributed scheme is also proposed by modifying the minimum weight k-path scheme. In the modified scheme, each RS makes a local decision to join different multicast trees based on the expected distortion among its connected downstream nodes. The proposed multicasting schemes require much lower implementation complexity, compared to the optimum solutions. The centralized scheme is more suitable for small size networks, and achieves close-to-optimum performance for a wide range of parameter settings. The distributed scheme only requires neighboring nodes to exchange information, and can be implemented to networks with a relatively large number of APs, RSs, and destination nodes. / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22873 |
| Date | January 2018 |
| Creators | Alganas, Abdulelah |
| Contributors | Zhao, Dongmei, Electrical and Computer Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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