Weightless (wireless communications)

Weightless is a proposed proprietary open wireless technology standard for exchanging data between a base station and thousands of machines around it using White space (frequency channels intended for TV broadcasting but currently unoccupied) with high levels of security. This technology allows to build Low-Power Wide-Area Network (LPWAN).

Weightless is managed by the Weightless SIG, or Special Interest Group, which was revealed to the public on 7 December 2012.[1] An inaugural event for industry was held at the Moller Centre in Cambridge, UK by Cambridge Wireless on Friday, 30 September 2011.[2] Representatives – mainly engineers – from many companies from around the world attended. Presentations were given by Neul, Landis+Gyr, Cable & Wireless, and ARM.[3]

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.

Name and logo

The name Weightless was chosen to reflect the allegedly light-weight nature of the protocol, meaning that the overhead per transmission is minimised for devices that need 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.[4]

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".

Implementation

Weightless uses Time-division duplex operation with frequency hopping and variable spreading factors in an attempt 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 for broadcasting television can be allocated for use by Weightless devices.[5]

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.

Communication and connection

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 local area.[6]

Uses

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 10 km.[7]

List of applications

Weightless vs. Wi-Fi (IEEE 802.11af)

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.

Weightless vs. Cognitive Radio (IEEE 802.22)

The IEEE 802.22 standard defines a MAC and PHY layer for TV WhiteSpaces that complies with the FCC and international standards for broadcasting in this spectrum. It also defines general protocol model for negotiating and selecting shared spectrum band for device operation. A Weightless Radio implementation would comply with this standard to cooperatively share the available TV WhiteSpace spectrum.

Devices

Currently the majority of the devices that are envisionsed to use the Weightless standard are mainly of industrial and medical type, such as smart electric meters, health monitors, vehicle tracking, etc.

Specifications and features

The Weightless specification was developed as a proprietary machine-to-machine, allegedly 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.[8] The specification is based on Time-division duplex technology with Spread spectrum frequency hopping in an attempt to minimise the impact of interference and with variable spreading factors in an attempt to increase range (at the expense of lower data rate) and to accommodate low power devices with low data rates.

The specifications allegedly have been finalised with the creation of version 1.0 in 2013.

Versions

Weightless v1.0

A formal standard was published in 2013, however it was not made freely available to general public -- it was only available to the members of Weightless SIG who paid membership fees. A brief and incomplete overview of the standard may be available without a charge to the so-called "observer members" of SIG.

Technical information

Setting up connections

A base station queries a database which identifies the channels that are being used for terrestrial television broadcast in its local area. 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 will be allegedly designed to be low cost "fit and forget" devices – meaning that they are expected to use minimal power so that they could work autonomously for long periods close to the typical shelf-life of a battery (probably several years).

Security Concerns

It is proposed that the entire data transmission is encoded. It is claimed that that the protocol was designed to be secure and guarantee message delivery.

Air interface

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 white space devices (such as those utilising Weightless). A range of modulation and 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 10 km away. Data rates may vary depending on the distance and the presence of radio interference – the typical range is alleged to be between about 0.1Mbit/s and 16Mbit/s. It is claimed that the design of the air interface and protocol attempts to minimises the costs of the equipment and its power consumption. A broadband downlink from a base station to a terminal uses single carrier in an unused 6 MHz (for USA) or 8 MHz (for UK) TV channel.

Security

The communications link between the base station and the devices is encrypted.

See also

References

  1. ↑ "M2M Standards group breaks cover". Weightless SIG. 2012-12-07. Retrieved 2013-01-09.
  2. ↑ "Inaugural Standards SIG (S-SIG)". Cambridge Wireless. 2011-09-30. Retrieved 2011-10-05.
  3. ↑ "Does white space need to be Weightless?". TheRegister.co.uk. 2011-09-25. Retrieved 2011-10-05.
  4. ↑ "What is Weightless?". Weightless SIG. 2011-09-30. Retrieved 2011-10-05.
  5. ↑ "White Space: The Next Big Thing in networks". TheRegister.co.uk. 2011-08-18. Retrieved 2011-10-05.
  6. ↑ "Cambridge gets a white (space) wash". TheRegister.co.uk. 2011-06-27. Retrieved 2011-10-05.
  7. ↑ "Cambridge startup launches world's first white space radio". TheRegister.co.uk. 2011-06-14. Retrieved 2011-10-05.
  8. ↑ "How to build a national cellular wireless network for £50m". TheRegister.co.uk. 2011-04-22. Retrieved 2011-10-05.

External links