Embedded mesh could also be used to simplify the collection of utility meter data in houses, or be built into light switches as a more flexible alternative to electrical wiring. Ember is working with the emerging ZigBee standard and is contributing parts of its EmberNet technology to ZigBee.
A mesh standard?
A host of other start-ups, including BelAir Networks, Tropos, FireTide and Strix Systems are all beginning to announce mesh products and customers. Currently different companies' systems all use proprietary technology bolted onto standards such as Wi-Fi, meaning the different types of equipment can't work together, a problem being addressed by standards groups.
Pressed by Intel, Cisco, MeshNetworks and others, the IEEE has formed a study group that could eventually build mesh into wireless LAN specifications; its first meeting was held in January. Critics say a standard could end up being a lowest-common-denominator approach lacking the efficiency of proprietary protocols. In the meantime, MeshNetworks has repackaged its mesh special sauce as licensable libraries aimed at wireless equipment manufacturers; these will be available in the second quarter of this year.
Mesh has its sceptics, who point out that it only makes sense in special circumstances. "I'm not sure enough people will pay for it for it to be built into equipment as standard," says Richard Mironov, vice president of marketing for wireless security firm AirMagnet. "If you're in a building with the capability for Ethernet wiring, mesh is not needed."
But mesh is not going away, Intel argues. "It lowers the barriers to deploying a network, and that can be applied to a lot of different scenarios," says researcher Lakshman Krishnamurthy. "Unlicensed spectrum usage allows wireless networks to be everywhere, and mesh is one element to that larger revolution."
Case study: City of Garland, Texas
Garland, located 15 miles northeast of Dallas and with a population of 221,000, is in the process of replacing the cellular-based communications system it uses for public safety workers such as police officers, fire fighters and medical emergency teams. Lockheed Martin Space Operations Division was awarded the contract last September and chose mesh technology from NexGen City, a system integrator using technology licensed from MeshNetworks. The new system will cover 57 square miles, and is touted as the largest mobile mesh network in the world. It is scheduled for completion in the second quarter of this year, initially providing mobile data, with the option of adding video and voice later on.
Mesh technology promises to greatly simplify things for Garland, while offering 50 times the bandwidth. "We eliminate expensive towers, subscriber fees, and zoning issue headaches associated with our old system," notes city telecommunications manager Darrell McClanahan. The mesh system supports sustained throughput of 1Mbps with bursts of up to 6Mbps.
Its components include PC cards, wireless repeaters, gateways, geo-location software, administration servers for command and control centres, and modified PocketPC handhelds (though these won't be in production until mid-2004). The repeaters and gateways are built into buildings, streetlights or traffic lights; they only need to provide enough power to communicate with the next device or repeater, so can operate at lower power than a cellular tower. The PC cards and PDAs also act as repeaters and routers, adding further nodes to the network and making the network more fault-tolerant. The geo-location software provides latitude, longitude and elevation information without the need for GPS. The system supports industry-standard TCP/IP, DHCP, and SNMP protocols.
Garland chose the scheme after NexGen City completed a test phase across a five-square-mile area along Texas' Highway 190 in 2003. In a demonstration, two networked vehicles travelling faster than 60 miles per hour in opposite directions exchanged real-time streaming video, voice over IP calls and data throughput of up to 1.5Mbps.
