Mesh Radio - New Generation Wireless Networks

Mesh Radio is a new type of high-capacity wireless network. Mesh Radio will let the users to watch movies on demand, hold broadcast-quality video chats with their neighbours, and download from the internet at a blistering four megabits per second - many times the speed of wired broadband delivery systems like ADSL and cable modems.

Mesh radio will not slow down when a lot of people try to use it at the same time. Home ADSL services typically provide a maximum data rate of 500 kilobits per second, but the bandwidth available to a user is much lower if several people in the street are online at the same time. 

Mesh radio achieves nearly 100 per cent cover by turning each home into a mini base station. A stubby unit on the roof, hides four directional antennas with motors that automatically align them with other antennas on other houses. This allows each node to communicate with several others at the same time. If contact is lost, it can automatically readjust its antenna to point to a different one.

 A network control centre - or master node - connects to an optical-fibre trunk line connected to video and Internet resources. The data flowing round the network is labelled so that each home has its own private, indirect connection to the trunk. 

 A wireless mesh network is a communications network made up of radio nodes organized in a mesh topology. The coverage area of the radio nodes working as a single network is sometimes called a mesh cloud. 

 

Wireless mesh architecture is built of peer radio devices that don't have to be cabled to a wired port like traditional WLAN access points (AP) do. Mesh architecture sustains signal strength by breaking long distances into a series of shorter nodes. Intermediate nodes not only boost the signal, but cooperatively make forwarding decisions based on their knowledge of the network, i.e. performs routing. Such an architecture may with careful design provide high bandwidth, spectral efficiency, and economic advantage over the coverage area.

This type of infrastructure can be decentralized (with no central server) or centrally managed (with a central server), both are relatively inexpensive, and very reliable and resilient, as each node needs only transmit as far as the next node. 

 Nodes act as routers to transmit data from nearby nodes to peers that are too far away to reach in a single hop, resulting in a network that can span larger distances. The topology of a mesh network is also more reliable, as each node is connected to several other nodes. If one node drops out of the network, due to hardware failure or any other  reason, its neighbors can find another route using a routing protocol. 

Mesh networks may involve either fixed or mobile devices. In difficult environments such as emergency situations, tunnels and oil rigs to battlefield surveillance and high speed mobile video applications on board public transport or real time racing car telemetry.  By using a Quality of Service scheme, the wireless mesh may support local telephone calls to be routed through the mesh.

 

• The principle is similar to the way packets travel around the wired Internet — data will hop from one device to another until it reaches its destination. 
• Dynamic routing algorithms implemented in each device allow this to happen. 
• To implement such dynamic routing protocols, each device needs to communicate routing information to other devices in the network. 
• Each device then determines what to do with the data it receives — either pass it on to the next device or keep it, depending on the protocol. 
• The routing algorithm used should attempt to always ensure that the data takes the most appropriate (fastest) route to its destination.

 

Multi-radio mesh

• The choice of the radio technology for wireless mesh networks is crucial. 
•  In a traditional wireless network where laptops connect to a single access point, each laptop has to share a fixed pool of bandwidth. 
•  With mesh technology and adaptive radio, devices in a mesh network will only connect with other devices that are within range.

There are more than 70 competing schemes for routing packets across mesh networks. Some of these include:

1. AODV (Ad hoc On-Demand Distance Vector)
2. OLSR (Optimized Link State Routing protocol)
3. DSR (Dynamic Source Routing)
4. OSPF (Open Shortest Path First Routing)