The benefits of a M2M / IoT future places new requirements on connectivity with the evolution of LTE a key component. LTE is becoming more viable for M2M / IoT applications by offering spectral efficiency, longevity, and scalability. LTE MTC (Machine Type Communications) will specifically address dramatic increases expected in the number of devices that will be deployed for M2M communications. The development and introduction of LTE MTC chipsets and modules is seen as a significant step for the cellular M2M market with solutions meeting the key requirements of low pricing, low power consumption, and network longevity.
Many anticipate that 4G LTE MTC will be the smoothest path to adoption as cellular operators shut down 2G networks to re-farm spectrum for more efficient 4G/LTE services. AT&T in the U.S. plans closure of their 2G network by January 1st 2017. All of Singapore’s 2G networks will shut down with M1, Starhub and Singtel announcing a joint shutdown on April 1st 2017. In Australia, Telstra’s 2G will be shut down on December 1st 2016 with Optus to following suit with their 2G network closure on 1st April 2017. Businesses with devices on 2G services have had early and continuing encouragement to migrate from 2G to 3G/4G technologies.
Cellular specialists, however, face competition from dedicated M2M/IoT networks such as SigFox and Semtech’s LoRa technologies that offer low power, low cost alternatives. SigFox, espousing a protocol designed specifically for the IoT, rather than one tweaked to address it, plans global expansion that include networks in Australia. Other technologies are competing in the M2M / IoT space and are gathering multivendor support. LoRaWAN backed by the LoRa Alliance, boasting 130 members has announced a certification program. While LoRa technologies have yet to be widely deployed in Australia, LoRaWAN networks are planned and trials are being conducted.
Global support over existing LTE cellular networks is a big advantage of LTE over alternative networks. LTE will expand into new usage scenarios by providing improved support for low-cost and energy-efficient MTC devices through reduced RF bandwidth. Applications envisioned for LTE MTC include metering, environmental & industrial monitoring, object location tracking, e-health, wearables and sensors. Lower latency will also enable support for new applications that include traffic safety/control and control of critical infrastructure and industry processes.
LTE current, and upcoming, standards for M2M/IoT include:
LTE Cat-1: Provides downlink data rate sufficient for most M2M applications. Enablement of single antenna implementation minimizes changes to current 2G/3G equipment designs. Most US mobile operators have committed/enabled Cat-1 on networks with a range of Cat-1 modules to be available from late 2015 through 2016 from various device manufacturers.
LTE Cat-0: Provides same single antenna cost optimisation as Cat-1 but with enhanced power saving mode (PSM) for extended battery life. Modules for Cat-0 may be available depending on operator support.
LTE Cat-M: Standard to be ratified with 3GPP in March 2016. Anticipated enhancements to Cat-1 include modem simplification, reduced bandwidth to 1.4MHz, range of power saving options for ultra-long battery life and extended coverage for remote/harsh environments.
Narrow-Band Long-Term Evolution (NB-LTE): This new specification is set to rival other narrowband LTE specifications for 3GPP’s consideration of choice of standards for 4G M2M / IoT communications. NB-LTE proponents argue that without the need for expensive network infrastructure and chipset investments, NB-LTE by leveraging existing LTE network technology enables fast adoption and economies of scale maximization.
Currently, LTE devices have full bandwidth of up to 20MHz typically supporting multiple bandwidths depending on the carrier frequency. Although this provides deployment flexibility and allows devices to exploit the full performance of the bandwidth used, a single small bandwidth on the radio side such as 1.4MHz allows for simpler radio implementation and lower device cost.
Release 13, supporting the coexistence of 1.4MHz narrow-band devices with current LTE devices on a single, wider-band carrier, will further reduce costs by offering low-cost MTC devices that operate using half-duplex and a single antenna, and will limit the data rate to 1Mbps without negatively impacting the performance of existing fully flexible LTE devices.
Exploiting unlicensed spectrum and complemented by multi-antenna enhancements, LTE Release 13 enhancements will improve overall capacity, user data rates and latency in combination with higher-layer protocols such as TCP. In Australia, LTE MTC on networks and device availability is still to be finalized. With wide availability of LTE MTC on the horizon, LTE is set to play a key connectivity role in the various applications that make up M2M / IoT solutions.