Weightless is a proposed proprietary open wireless technology standard for exchanging data between a base station and thousands of machines around it (using wavelength radio transmissions in unoccupied TV transmission channels) with high levels of security.
Weightless is managed by the Weightless Special Interest Group, which is proposed for launch in the autumn of 2011. An inaugural event was held at the Moller Centre in Cambridge, UK by Cambridge Wireless on Friday, 30 September 2011.[1] Representatives - mainly engineers - from many companies from around the world attended. Presentations were given by Neul, Landis+Gyr, Cable & Wireless, ARM, and Itron.[2]
The intention is that devices must be qualified by the Weightless Special Interest Group to standards defined by the SIG. Patents would only be licensed to those qualifying devices; thus the protocol, whilst open, may be regarded as proprietary.
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The name Weightless was chosen to reflect the light-weight nature of the protocol, meaning that the overhead per transmission is minimised for devices that want to communicate just a few bytes of data.
The Weightless logo is trademarked and appears as uppercase letters with the 'W' appearing in the top-right corner of a light blue box that has a solid blue line above it.[3]
One of the presenters at the inaugural SIG event in September 2011 stated jokingly, in reference to cellular communication standards, "Weightless is not 1G, 2G, 3G or even 4G - it is ZERO G".
Weightless uses Time-division duplex operation with frequency hopping and variable spreading factors to increase range and accommodate low power devices in frequency bands, or channels, within the terrestrial television broadcast band. Channels that are in use by a nearby television transmitter are identified and left unaffected while channels not being used by broadcast television can be allocated for use by Weightless devices. [4]
A network of base stations communicate with the Internet, or a private network, in order to pass information from devices to a computer system; and to pass information back to the devices. The downlink to devices uses time slots (TDMA) and the uplink to the base station is divided into sub-channels so that several devices can communicate to the base station.
A base station transmits a Weightless frame which is received by a few thousand devices. The devices are allocated a specific time and frequency to transmit their data back to the base station. The base station is connected to the Internet or a private network. The base station accesses a database to identify the frequencies, or channels, that it can use without interfering with terrestrial television broadcasts in its area.[5]
Weightless is a wireless communications protocol designed to connect Smart Machines to the Internet - so-called Machine-to-Machine (M2M) communications - over distances ranging from a few metres to about 10km.[6]
Other technologies which use the white space - the channels not used for terrestrial television broadcast in a particular area - are also being developed. One is Wi-Fi under the developing standard IEEE 802.11af.
Devices that use the Weightless standard are envisioned to be mainly industrial - smart power meters, health monitors, vehicle tracking, and the like.
The Weightless specification was developed as a machine-to-machine, low-cost, low-power communication system for use in the white space between TV channels in 2011 by engineers working at Neul in Cambridge, UK.[7] The specification is based on Time-division duplex technology with Spread spectrum frequency hopping to minimise the impact of interference and variable spreading factors to increase range and accommodate low power devices.
The specifications are not yet formalized - a new Weightless Special Interest Group (SIG) is proposed for creation in autumn 2011.
A formal standard is still being defined.
A base station queries a database which identifies the channels that are being used for terrestrial television broadcast in the area around the base station. The channels not in use - the so-called white space - can be used by the base station to communicate with terminals using the Weightless protocol.
Terminals are designed to be low cost "fit and forget" devices - meaning that they use minimal power so that they last for many years, perhaps close to the typical shelf-life of a battery.
It is proposed that the entire data transmission is encoded. The protocol is designed to be secure and guarantee message delivery.
The protocol operates initially in the TV channels band in the USA and UK. The Weightless protocol divides the band into channels. A database is queried by a base station to determine which channels are in use by terrestrial television broadcast stations in the area, and which ones are free for use by the Weightless protocol. A range of modulation encoding techniques are used to permit each base station to communicate at a variety of speeds with terminals, some of which may be nearby and others up to 10km away. Speeds vary depending on the modulation used, the distance and the interference - the typical range is between about 0.1Mbps and 16Mbps. The design of the air interface and protocol minimises costs and power consumption. A broadband downlink from a base station to a terminal uses single carrier modulation with an unused 6 or 8MHz TV channel.
The communications link between the base station and the devices is encrypted.
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