## 1 Introduction  
Wireless mesh networks (WMNs) are dynamically self-organized, self-configured, self-healing, and easy-to-install multi-hop networks. This type of networks are becoming a promising wireless technology that has great potential to provide multimedia services over large coverage areas in the future [1]. WMNs can provide the same level of network reliability, capacity, and security as wired networks. In recent years, there has been an increasing demand for quality-of-service (QoS)-demanding real-time and multimedia applications, such as audio and video, in large application areas. These QoS-demanding applications are promoted for two reasons: one is the pervasive use of computing devices, such as laptop computers, personal digital assistants, video surveillance cameras, automotive computing devices, smart phones, and wearable computers; and the other is the fast-growing deployment of multi-hop wireless mesh networks to connect these computing devices [2]. In the past, WMNs were only considered to provide \"last mile\" internet access, but now high capacity WMNs are being rapidly deployed in large business organizations, industries, airports, military bases, ports, and borders for remote monitoring, to locate and track high-value equipment for theft protection to provide real-time video feeds to first responders for staff safety in emergency situations, and to provide variety of other multimedia applications and services. Such WMNs are deployed and owned by individual organizations for their exploitation and their access is not publically available. We call such WMNs private WMNs (PWMNs), and it is expected that the video surveillance market for PWMNs will be a $37 billion market in 2015 [3]. In multi-hop, multi-channel WMNs, the nodes are equipped with inexpensive and readily available 802.11 multiple radios, by which they can exploit the IEEE 802.11 defined orthogonal channels to enhance the overall network capacity. However, the availability of orthogonal channels is limited, e.g., three orthogonal channels are defined for 802.11 b, and 12 orthogonal channels are defined for 802.11 a. Furthermore, interference with the adjacent nodes adversely affects the capacity of WMNs [4]. Channel assignment (CA) is a key issue in guaranteeing network connectivity and leveraging the capacity of WMNs. A WMN node must share a channel with neighboring nodes with which it wants to establish connectivity. Most of the CA schemes have been proposed to address connectivity and capacity issues of WMNs, which are mainly categories into three categories, static, dynamic, and hybrid. In [4,5] static and interference-aware CA approaches are addressed, dynamic interference-aware CA approaches are discussed in [6,7] while hybrid CA approach is presented in [8]. The hybrid and dynamic approaches are more attractive because they allow channel switching among available channels according to the packet destination, but radio switching from one channel to another channel induces further delay, which is in the range of a few hundred microseconds to a few milliseconds. Furthermore, the current IEEE 802.11 cannot guarantee a mechanism for nodes to switch radios on a packet basis. Therefore, it is reasonable to allocate the channels to the radios on the mesh backbone nodes statically or permanently [4]. Routing protocols can be categorized into two major classes in the context of the types of applications and services they support: (1) QoS provisioning routing that enables multimedia and other QoS demanding applications; (2) conventional routing that enables non-real time and multimedia applications. These two different types of routing can cause two different network problems in their respective fields of application. Conventional routing induces resource overutilization problems [9; 10; 11]. In resource overutilization, many traffic flows share the same network resources (e.g., router buffer and data channel), which may cause network congestion that reduces the overall network throughput.