## 1 Introduction  
Modern information society has the increasing need for Internet access, as the global network for information circulation. Nowadays, it is necessary to obtain Internet access for all types of network devices (fixed and mobile wireless devices), in any possible way and at any place. This is extremely important if we bear in mind that the use of wireless devices, like smart phones, mobile phones, PDAs, laptops _etc._ is on the increase. These demands impose the need for large infrastructure, which is often impossible to realize, especially in rural areas. This type of problems can be solved to a great extent with the use of Mobile _Ad Hoc_ Networks (MANETs) [1; 2; 3; 4; 5]. MANET presents large-scale multi-hop wireless network which is very applicable for quick access and wide area coverage [1; 3; 5]. One specific type of mobile _Ad Hoc_ network is the wireless mesh network (WMN) [6; 7; 8; 9]. A WMN is the set of wireless nodes, which communicate in such a way that they mutually transfer all packets within the network. This relatively new wireless multihop technology is organized as a mesh topology and can be a revolutionary solution for gaining access to wireless networks [10]. Like in a MANET organization, a WMN also has nodes that behave simultaneously both as host and as wireless router. In that way, each node has both mesh router and mesh client functions. The most common role of WMNs is to gain quick wireless network access and connection to the Internet. For that reason, there are two main types of nodes: the nodes that are part of the network and don't have direct connection to Internet (called WMN routers), and nodes that do have Internet connection (called gateways) [11]. There is a distinction between several types of links within the network, where only intra-mesh links are wireless and all others can be either wired or wireless. As an illustrative example, in Figure 1 the block diagram of typical WMN is depicted. Figure 1: The structure of the WMN. Link connections between gateways and Internet can also be wired or wireless and are is supposed to be reliable, so it will not be discussed in the paper further on. A WMN defined in this way is suitable for establishing wireless communication between subscribers and the Internet. Standard new generation devices (laptops, PDAs, PocketPCs, phones, _etc._) which have wireless network interface cards (NICs) can be directly connected on wireless mesh routers, and that way access the Internet through a WMN. Subscribers who don't have NIC can be connected to the WMN using Ethernet directly through mesh routers. WMN defined in this way is dynamically self-organized, self-configured, self-optimizing and fault tolerant with the nodes in the network automatically establishing and maintaining mesh connectivity among themselves [12, 13]. All these performances clearly indicate that WMN has advantages such as low investment overhead, easy network maintenance, fast to deploy, robustness and reliable service coverage. In that way, WMNs have become a favorable solution for neighborhood networks, enterprise networking, communities, _etc._ A large number of companies have based their solutions on WMNs. IP solutions using WMNs have been also created by Nokia, Microsoft, Motorola, Intel, _etc._[11, 12]. Constructing WMNs requires initial creation of a network from various numbers of mesh routers and mesh clients. Mesh routers can be stationary, set on the building roofs or high spots in the air, while mesh clients can be mobile and in that way communicate with the other wireless routers. The gateways are mostly stationary wireless routers, which make connections with other networks or Internet through a wired medium. In this way, the price of Internet access has decreased dramatically compared to classical wired systems (cable-modem and xDSL). So, the advantages compared to fixed wireless metropolitan area networks (WMANs) are seen in multiplied routes.