Mobile network operators (MNOs) and the media have tended to focus on LTE's cellular data rates, which started out with downlink peak rates of 300 Mbps but will reach 1 Gbps in the not-too-distant future. That's impressive, but right now these rates are overkill and likely to remain so for the foreseeable future. What's really impressive about this networking technology is its efficiency and flexibility, and that is why LTE is set to become the global standard.
However, MNOs have also, through their use of terminology, confused the market. LTE (Long Term Evolution) was marketed as 4G, but technically it was 3.9G. LTE-Advanced, which is making its way to the market, delivers real 4G performance, as defined by the ITU.
But if we put that confusion aside, along with the issue of data rates, and open up the hood, then we see a simple, flat, all-IP architecture that is significantly more efficient than that of earlier generations. 4G networks can accommodate up to 10 times more traffic, and latency is 10 times lower.
LTE also introduced OFDM (orthogonal frequency-division multiplexing), a method of digital modulation in which a signal is split into several narrowband channels having different frequencies. This technology allows bandwidth to be assigned in a very flexible way, and that should lead to cost-effective, low-bit-rate services.
Put the huge increase in traffic-carrying capacity together with these services, add low latency and scalability (enabled by support for IPv6), and it's clear that the combination will do more than merely facilitate the deployment of M2M and Internet of Things (IoT) devices: in fact, it's the only way of realizing the much heralded IoT era.
This means that the market will drive the deployment of 4G networks. LTE provides a superior solution to the technology of earlier cellular networks, and the performance is particularly relevant to applications for which speed and responsiveness matter. In fact, low latency will enable connected applications that would not otherwise be possible.
Too many networks out there
Cellular GSM technology has transitioned from 2G to 3G and on to 3.5G (HSPDA) and 3.75G (HSPDA +). However, maintaining all these earlier networks is expensive. In the U.S., CDMA is employed, but development work on this technology stopped some time ago. Operators are therefore going to retire networks that are less efficient, and this process has started--e.g. AT&T has announced plans to sunset its 2G network by January 1, 2017. It will be slow progress because the market will need time to adapt, but having one global standard makes a lot of sense for users and operators.
LTE and M2M
Operators have made significant investments in the new infrastructures. LTE is not an incremental upgrade: network cores had to be changed in order to employ OFDM. Therefore, operators will continue to promote high-speed, high-margin services that meet the performance requirements of applications such as video, security and infotainment.
Right now, the deployment of M2M solutions is constrained by the relatively high price of LTE modems, but these costs will decline. And in high-volume sectors like automotive and smart energy meters, where it is impractical to retrofit the devices, vendors are seeing LTE as the only way of future-proofing their solutions.
In addition, the total cost of ownership (TCO) has to be considered. The initial hardware cost will be higher, but that can be offset against potentially lower operating costs. Sierra Wireless and Telit here, as well as other leading module vendors, are developing less expensive ways of deploying and managing M2M apps in order to reduce the TCO.
Currently, LTE uses its larger bandwidth to deliver faster data rates, but the fact that most M2M apps don't need high-speed performance means some of that spectrum can be used to improve coverage for in-building security and environmental control systems.
Developments in low-speed performance
LTE was designed to accommodate high-speed, low-latency traffic: that was the primary goal. However, it turns out that OFDM also enables the delivery of low-speed, cost-effective services--but on the performance front, there's room for improvement. MNOs, standards bodies and vendors are cooperating in order to optimize the LTE standard for a broader range of M2M applications. In other words, this industry is reacting to the huge potential of the emerging IoT market.
Developments are underway on support for a new class of low-cost LTE devices that:
* operate at sub-1 Mbps data rates;
* use a half-duplex mode and a single receiver; and
* employ lower transmit power to reduce consumption and hardware costs.
In addition, new non-3GPP cellular standards are emerging that are fully optimized for M2M and similar applications, and which promise to dramatically bring down the barriers of cost and power consumption. One of these standards is Weightless, which has a specially designed radio interface and network architecture specifically to serve M2M profile needs.
Another area is the protocol stack. NextG-Com has announced availability of ALPS-Lite, which is a customizable, lightweight protocol stack, designed for low-cost, low-bandwidth, low-power M2M platforms. ALPS-Lite is fully validated against the 3GPP conformance test suite.
The driver for this development is the industry's need for solutions that alleviate high cost and high footprint requirements of regular LTE devices, while meeting operators' preference for spectral efficiency and future-proof deployments. NextG-Com is member of the Weightless SIG.
LTE in the enterprise
Thanks to both high-bandwidth applications and M2M-type services, LTE service revenues are expected to reach $75 billion this year, according to the latest numbers from Juniper Research. New service offerings aimed at enterprise users will appear--for example, premium data plans offering high QoS guarantees; fast and immediate service upgrades; QoS guarantees for telepresence and cloud applications; plus support for M2M and embedded devices.
In addition, more applications will be used on mobile devices. There will be faster or real-time sharing of large files and streaming media, and near-immediate delivery of time-sensitive data, e.g., for real-time interaction or transactions.
Conclusions
Right now, solutions for high- and low-speed M2M applications are evolving along two different paths. Those providers that can benefit from high-speed, low-latency performance are rapidly adopting LTE. Take-up for the remainder is relatively slow: most solution providers will stay with earlier-generation cellular modules. But convergence is inevitable, given LTE's key features--efficiency, flexibility and scalability.
The next few years will be an exciting time for M2M, and providing the industry with the optimum technology for the widest range of applications will be crucial in ensuring that the ambitious growth forecasts will be achieved.
