For the most part, these technologies are optimized for sensor networks with very low data volumes, such as for smoke detectors or fill sensors on waste bins. They have an advantage in their very high range and in that they use license-free frequencies. One prominent representative is SIGFOX. The network uses an ultra-narrowband technology and is already employed in several national networks. SIGFOX is optimized for the occasional transmission of very small data packets and permits reception only during a short time window immediately after messages are sent.
Another example is LoRa. The industry representatives for this technology have formed the LoRa Alliance. Based on the LoRa technology from Semtech, they have specified the LoRaWAN standard and an additional specification for the certification of compatible devices. LoRa uses a type of frequency-modulated spread spectrum technology similar to that used for radar applications. It supports three classes of devices. Class A permits reception only during two short receive windows occurring after messages are transmitted, similar to SIGFOX. Class B permits periodic receive windows that are synchronized via beacons. Class C devices are always ready to receive unless the device is currently transmitting. Additional examples of LP-WAN technologies are Weightless-N and RPMA.
GSMA – ultra-low-cost devices
The GSMA also committed to the Internet of Things some time ago, and this year has launched an LP-WAN initiative. The goal is to define LP-WAN standards as quickly as possible based on the established cellular standards in the licensed spectrum. The major infrastructure, modem and chipset manufacturers have rushed to work with the mobile service providers in order to develop an appropriate standard. The intent is to approve the standard in Rel. 13 and to permit introduction of commercial products in 2016. The first field trials are already underway.
A number of technical discussions and alternative approaches are ongoing. However, the committee has already decided that there should be a narrowband IOT (NB-IoT) standard. This standard would permit the use of resource blocks from LTE carriers, unused resources in the spectrum between neighboring carriers or resources in a separate, reserved spectrum. The requirements profile for this standard includes extremely low power consumption, very low costs, improved reception in buildings and support for an enormous number of devices with very little data traffic.
A large number of standardization activities are underway to ensure that the appropriate communications technologies are available for the future in the Internet of Things. These activities will also pave the way for the fifth generation of mobile radio, for which extremely low latency, very long battery life and an enormous number of devices also play a large role.
