Weightless

Introduction
Weightless is a LPWAN technology, which are characterized by long ranges and low power consumption. It is a fully open and very versatile standard that suffers from a shorter range of approximatively 2km but has many options that allow it to fit in different environments. It offers different choices for all the main parameters, including the modulation scheme and the frequency.

Technological description
Like the other LPWAN technologies, Weightless offers acceptable range for very low power consumption. However, it has a short range of only 2km compared to the other technologies in that category, which reach 10km. This fully open standard uses narrow band channels to provide good noise robustness, and has many parameters that can be adjusted to fit in any situation, making Weightless very flexible. Thanks to a bandwidth optimization with FDMA and TDMA, it reaches slightly higher data rates (up to 100 kbps) than the other LPWAN alternatives (about 50kbps in the mean). Reliability mechanisms based on ACK and automatic retransmission are implemented to ensure reliable communications. Weightless is robust even if numerous devices are present, and it avoids interferences and collisions thanks to an active frequency switching strategy. This means that if a host on the Weightless network detects an interference, all the nodes will switch to another frequency to avoid quality loss. Weightless' flexibility is found in the following parameters, that can be adapted to fit the use case:
 * AES-128 and AES-256 are available to adjust the desired data security level
 * multiple modulation schemes are possible: O-QPSK, GMSK, spread-spectrum
 * it is commonly used in the Sub-GHz ISM frequency band, but Weightless can also be configured to work in licensed frequency bands without any adaptation needed

Sources and further information
http://www.eetimes.com/document.asp?doc_id=1327380

http://www.weightless.org/

Weightless SIG et al. "LPWAN Technology Decisions: 17 critical features." 2016