It may be somewhat surprising, but the latest generation of cellular technology, LTE, is the most successful standard in telecom history. Overcoming the geographical challenges of GSM by reaching across the US, and bringing high-speed data to all manner of wireless devices, the adoption of LTE is phenomenal by any standard. With over 500m subscribers on 335 networks in 118 countries, the technology is becoming ubiquitous with cellular users. But this is also giving system architects more options for connecting up devices and set to see an explosion in the volume of data and the uses of LTE over the next few years.
Figure 1: Global mobile data traffic (Source: CISCO VNI Mobile 2015)
The low latency is a key element in the popularity of the technology that is reaching into ever more applications. LTE was designed with a low latency of 10ms, and the new LTE Machine Type Communication (MTC) specification brings the prospect of using this technology for machine-to-machine links. It may seem like overkill to use a high bandwidth channel that can support 150Mbit/s downloads and 50Mbit/s uploads for links that may need just a few kilobits. However, it is the latency and the overall cost effectiveness that makes LTE ideally suited for M2M. Instead of having to set up and break down dedicated channels, all kinds of machines can connect quickly and easily to the cloud. This is allowing large amounts of data to be aggregated quickly and easily to provide actionable real time information from across an industrial site or across a continent. New variants of the specification called category 0 and Category 00 will provide an even more optimised implementation for the low speed links that will be even more power efficient, allowing LTE links in considerably more places.
Figure 2: The number of wirelessly connected M2M devices is forecast to exceed all other types of connected devices by 2020 (Source: GSM Association)
At the same time, the spectral efficiency allows operators to provide data services of all kinds more cost effectively with the existing LTE technologies than 3G or GSM technology. For M2M applications, that means that the data can be a simple update from a sensor, or a high bandwidth real time video link on a vending machine, all using the same technology for the connection.
This fast connection also saves power, which is a key consideration for wireless M2M nodes that may be battery-backed. Setting up and sending a quick burst of data means less energy is used, reducing the load on the battery. This increases the time the battery can support the module and gives a longer time between battery replacement cycles, which is one of the major costs of an M2M roll out.
Scalability is also essential for designers. Having a standard footprint for the LTE modules to sit on a printed circuit board gives significant flexibility. Modules are available in various interface standards such as mini PCIe and the soon-to-be-available PCIe M.2 form factors; in addition to standard surface mount solutions for embedding onto customer PCBs. By using a common LTE engine across the range this allows designers to use any one of the u-blox family of LTE modules whilst keeping their own driver firmware unchanged, making it much easier for them to connect their systems to the cloud and to innovate with new software and data services.
The fastest growing, most popular telecoms standard in history is only just starting to make an impact. New variants of LTE will make wireless connections easier, more cost effective and lower power, driving this connectivity into more and more applications. This in turn will open up new ways of connecting up machines, analysing data and delivering a whole world of opportunities to customers.