A new topology of wireless LANs, the Mesh networks, is gaining the attention of the international scientific community and has led the IEEE to the creation of a special working group, IEEE 802.11s. A WLAN mesh network is an IEEE 802.11 WLAN infrastructured network in which the communication within the Access Points in the same Extended Service Set (ESS) is hop-by-hop in a router-like fashion.
This type of Internet infrastructure is decentralized, relatively inexpensive, and very reliable and resilient, as each Access Point (AP) needs only transmit as far as the next AP. APs act as repeaters to transmit data from nearby APs to peers that are too far away to reach, resulting in a network that can span large distances, especially in adverse conditions. Mesh networks are also extremely reliable, as each AP is connected to several other APs. If one of them drops out of the network, due to hardware failure or any other reason, its neighbors simply find another route. Extra capacity can be installed by simply adding more APs. Mesh networks involve mostly fixed or low-mobile APs.
A mesh network can be the ad hoc opportunistic extension of a fixed urban infrastructure. Now, the “fixed” urban infrastructure is itself undergoing a dramatic evolution. The traditional wireless systems have mostly used cellular-phone-style radio links, with point-to-point or point-to-multipoint transmission. These wireless formats have liabilities in industrial and urban applications such as rigid structure, meticulous planning requirements, and dropped signals.
In this project we direct our attention to such networks. The main characteristic of mesh networks is that they are "individual" centric rather that "mission" centric. As such, they cater to the need of the individual and his/her interactions with environment, Internet and other peers. Specifically, we are interested in the way these mesh networks form, and they intercommunicate among peers, with the surrounding environment and the Internet. Applications of WLAN Mesh networks are the digital home and the office scenario. In this case the primary purposes for the mesh network are to create a low-cost, easily deployable, high performance wireless coverage. With wireless mesh networks, enterprises can reduce costs associated with cable installation and reduce time required for its deployment. Moreover the mesh network eliminates RF dead-spots and can provide extra capacity if needed. Stations are a combination of PCs, laptops, PDAs, printers, digital cameras, MP3 players, DVD players, home automation devices such as control panels.
We identify and address challenges of this design ranging from optimum routing protocols to achive fairness and load balancing, to quality-of-service (QoS) MAC and network protocols to support emerging multimedia applications, to the need to guarantee efficient autonomous operation when the infrastructure fails.
|
