Wireless Mesh Network Project

Despite the impressive penetration of various modes of communications (mobile telephony, Internet, smart phone platforms for internet use, optic fiber cables, expansion of broadband services etc) the last mile connectivity is always a problematic issue. This is particularly acute in remote and rural areas, and in hilly and forested regions. The problem confronts both people and institutions located in these areas.
Solutions to the last mile connectivity problem are offered in terms of wimax and similar wired systems. These are typically quite costly. A far better, robust and cost effective solution is presented by what are called wireless mesh networks.

MESH NETWORK

A mesh network is a network topology in which each node (called a mesh node) relays data for the network. All nodes cooperate in the distribution of data in the network. It is designed using either a flooding technique or a routing technique. When using a routing technique, the message is propagated along a path, by hopping from node to node until the destination is reached. To ensure all its paths' availability, a routing network allows for continuous reconfiguration around broken or blocked paths, using self-healing algorithms. A mesh network whose nodes are all connected to each other is a fully connected network. The self-healing capability enables a routing-based network to operate when one node breaks down or a connection goes bad. As a result, the network is typically quite reliable, as there is often more than one path between a source and a destination in the network. Although mostly used in wireless situations, this concept is also applicable to wired networks and software interaction.

WIRELESS MESH NETWORK

A wireless mesh network is a communications network made up of radio nodes organized in a mesh topology. Wireless mesh networks generally consist of mesh clients, mesh routers and gateways. The mesh clients can be laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways which may, but need not, connect to the Internet. The coverage area of the radio nodes working as a single network may be called a mesh cloud. Access to this mesh cloud is dependent on the radio nodes working in harmony with each other to create a radio network. A mesh network is reliable and offers redundancy. When one node can no longer operate, the rest of the nodes will still communicate with each other, directly, or through one or more intermediate nodes. Wireless mesh networks can self form and self heal.
NECTAR has implemented two types of wireless Mesh nets:

  • Mesh Network for education and health services
  • Mesh Network for video/CCTV based real time surveillance system

NECTAR MESH NETWORK

Salient features

  • Architecture: Each node is a Software Defined Radio (SDR) configured to operate on frequency ranges of 5 to 10 GHz which allows very high data throughputs from 300 to 1000 Mbps. The nodes are not cabled to one another. This infrastructure carries data over large distances by splitting the distance into a series of short hops. Intermediate nodes boost the signal and cooperatively pass data from point A to point B by making forwarding decisions based on their knowledge of the network, that is, perform routing. This design provides high bandwidth, spectral efficiency, and economic advantage over the coverage area.
  • Management: 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 the network is also 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 quickly find another route using the routing protocol. Dynamic routing algorithms result in optimization and efficiency in the data transfer functions.

Performance features:

  • Very low power consumption
  • High speed data transfer
  • Low cost
  • Low maintenance
  • Usable on open frequency bands with no proprietary licensing charges (power limitations apply)

Advantages:

  • Mesh Implementations allow very high data throughputs up to 300Mbps on 2.4/5 GHz and up to 1000Mbps at 10 GHz. They are an ideal solution for deployment in undulating terrain where laying of cables can be problematic or even impossible.
  • Mesh nodes can be used for very high speed networks for use in urban/rural scenarios. They are an ideal fit for Indian conditions due to the low power requirements.
  • Mesh networks have very low latency and as such are an ideal backbone for CCTV and surveillance platforms.
  • Mesh networks use much lower power than competing technologies such as Wimax
  • Mesh networks are self healing and self forming and as such need less maintenance compared to competing technologies
  • Cost advantage over competing technologies can be as high as 3 to 4 times.

Implementation

  • A high speed mesh network has been commissioned in Nagaland for the health and education services. The Primary Health Centers and the Community Health Centers of the State have been interconnected and integrated with the State Health Department and the Deputy Commissioners establishment. The infrastructure, comprising of nearly 40 nodes, is available for tele-education also.
  • Meshnet for developmental use has also been set up in Tura District in Meghalaya.
  • A Mesh Network for video/CCTV based real time surveillance system is currently being implemented in Guwahati for the Assam Police.