Weightless was a set of low-power wide-area network (LPWAN) wireless technology specifications for exchanging data between a base station and many of machines around it.
History
Cambridge Wireless held an event at the Moller Centre in Cambridge, United Kingdom on September 30, 2011. Neul, Landis+Gyr, Cable & Wireless, and ARM Holdings provided presentations. The Weightless Special Interest Group promoted the technology (SIG), announced on December 7, 2012. The group was led by William Webb, a professor at Cambridge and a founder of the company Neul. A subsequent event was held in September 2013, when version 1.0 was published.
The name Weightless was chosen to reflect the intention at a low overhead per transmission for devices that need to communicate just a low amounts of data. The Weightless logo appears in uppercase letters with the 'W' appearing in the top-right corner of a light blue box with a solid blue line above it.
In September 2014, Neul was acquired by Huawei for an estimated $25 million. By 2015, the company Nwave Technologies announced deployments in Copenhagen, Denmark, and Esbjerg, Denmark. However, observers noted no products on the market. A company called Ubiik, based in Taiwan, announced pre-orders in 2017.
Implementation
Weightless-N uses a differential binary phase shift keying (DBPSK) digital modulation scheme to transmit within narrow frequency bands using a frequency hopping algorithm for interference mitigation and enhanced security. It provides encryption and implicit authentication using a shared secret key regime to encode transmitted information via a 128-bit AES algorithm. The technology supports mobility with the network automatically routing terminal messages to the correct destination. Multiple networks, typically operated by different companies, are enabled and can be co-located. Each base station queries a central database to determine which network the terminal is registered to decode and route data accordingly.
Weightless-W 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 used 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.
A network of base stations communicates with the Internet, or a private network, to pass information from devices to a computer system; and data 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 with the base station.
Initially, there were three published Weightless connectivity standards Weightless-P, Weightless-N, and Weightless-W. Weightless-N was an uplink-only LPWAN technology. Weightless W was designed to operate in the TV whitespace. Weightless-P, with bi-directional, narrowband technology intended to be operated in licensed and unlicensed ISM frequencies, was then just called "Weightless."
Communication and Connection
A base station transmits a Weightless frame received by a few thousand devices. The devices are allocated a specific time and frequency to transfer 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.
Weightless is a wireless communications protocol for machine-to-machine (M2M) communications known as the Internet of things (IoT) – over distances ranging from a few meters to about 10 km.
Related technologies
Other technologies which use the channels not used for terrestrial television broadcast in a particular area are also said to be in development. One is Wi-Fi under the standard IEEE 802.11af. The IEEE 802.22 standard defines a MAC and PHY layer for TV white spaces that comply with the FCC and international standards for broadcasting in this spectrum. It also defines a general protocol model for negotiating and selecting a shared spectrum band for device operation. A Weightless Radio implementation would comply with this standard to cooperatively share the available spectrum.
Another technology is developed by the company Sigfox.