Access-Point Allocation Algorithms for Scalable Wireless Internet-Access Mesh Networks

With rapid developments of inexpensive small-sized communication devices and high-speed network technologies, the Internet has increasingly become the important medium for a lot of people in daily lives. People can access to a variety of information, data, and services that have been provided through the Internet, in addition to their personal communications. This progress of the Internet utilization leads to strong demands for high-speed, inexpensive, and flexible Internet access services in any place at anytime. Particularly, such ubiquitous communication demands have grown up among users usingwireless communication devices. A common solution to them is the use of the wireless local area network (WLAN). WLAN has been widely studied and deployed as the access network to the Internet. Currently, WLAN has been used in many Internet service spots around the world in both public and private spaces including offices, schools, homes, airports, stations, hotels, and shopping malls. The wireless mesh network has emerged as a very attractive technology that can flexibly and inexpensively solve the problem of the limited wireless coverage area in a conventional WLAN using a single wireless router (Akyildiz et al., 2005). The wireless mesh network adopts multiple wireless routers that are distributed in the service area, so that any location in this area is covered by at least one router. Data communications between routers are offered by wireless communications, in addition to those between user hosts (clients) and routers. This cable-less advantage is very attractive to deploy the wireless mesh network in terms of the flexibility, the scalability, and the low installation cost. Among several variations of under-studying wireless mesh networks, we have focused on the one targeting the Internet access service, using only access points (APs) as wireless routers, and providing communications between APsmainly on theMAC layer by thewireless distribution system (WDS). From now, we call this Wireless Internet-access Mesh NETwork as WIMNET for convenience. At least one AP in WIMNET acts as a gateway (GW) to the Internet (Figure 1). To reduce radio interference among wireless links, the IEEE802.11a protocol at 5GHz can be adopted to links between neighbouring APs, and the 802.11b/g protocol at 2.4GHz can be to links between hosts and APs. Each protocol has several non-interfered frequency channels. Here, we note that IEEE 802.11s is the standard to realize the wireless mesh network so that a variety of vendors and users can use this technology to communicate with each other without problems. On the other hand, WIMNET is considered as a general framework for the wireless 2