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Wireless Mesh Networks 2010 Part 8

Tham khảo tài liệu 'wireless mesh networks 2010 part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Trends and Challenges for Quality of Service and Quality of Experience for Wireless Mesh Networks 129 The remainder of this chapter is organized as follows. Section 2 discusses quality of level issues in WMNs. Cross-layer schemes are described in Section 3. The implementation and validation of a WMNs routing solutions are presented in Section 4. Finally Section 5 presents the final considerations. 2. Quality of level support in wireless mesh networks This section discusses the main approaches to assure quality level support for multimedia applications in wireless mesh networks with focus on QoS and QoE issues. 2.1 Quality of service issues End-to-end quality of service control for fixed and mobile users is a core requirement for the success of emerging wireless systems. This control aims to increase the user satisfaction while enlarging the revenue to network operators. With this goal in mind the Internet has been a heavily researched topic in QoS networking for more than one decade. Several QoS models have been proposed with the goal of enriching the Internet with QoS guarantees that the current best effort model cannot support. Each approach defines its own mechanisms and parameters for traffic control and resource management although usually at different granularities. It is common for a QoS model to be based on the notion of a class as supported by well-know QoS models such as Differentiated Service DiffServ IEEE 802.11e IEEE 802.16d and Universal Mobile Telecommunication System UMTS . Trends in last-mile Internet access require new QoS control mechanisms for IEEE 802.11s mesh networks . However the end-to-end QoS support in such scenarios is not trivial and is a research challenge. First of all they must assure the high capacity needs of the access nodes that have to forward the accumulated traffic of their underling users. Moreover WMNs have to cope with multiple strict QoS requirements of a large number of multimedia applications including packet delay .