Opening up LTE for IoT

Today, LTE is the fastest growing wireless standard in history with over 300 commercial networks already launched as of mid-2014 and LTE subscriptions predicted to reach 1.6 billion by 2018. With this huge worldwide investment and momentum building, cellular operators are looking at how they can leverage that investment into the rapidly growing IoT space.


December 2, 2014

6 Min Read
Opening up LTE for IoT periodically invites expert third-party contributors to submit analysis on a key topic affecting the telco industry. In this article David Maidment, Mobile Segment Manager at ARM, discusses The Internet of Things phenomenon and how the forthcoming Cat-0 LTE specification can help operators better capitalize upon it.


Today, LTE is the fastest growing wireless standard in history with over 300 commercial networks already launched as of mid-2014 and LTE subscriptions predicted to reach 1.6 billion by 2018.  With this huge worldwide investment and momentum building, cellular operators are looking at how they can leverage that investment into the rapidly growing IoT space.

IoT represents an exciting opportunity for device manufacturers, service providers and consumers alike.  The ability to connect billions of ‘things’ to the internet is set to profoundly change the way we all interact and make use of countless devices that we encounter in our day to day lives.

There is of course nothing specifically new about this vision, machine-to-machine services (M2M) have been in existence for decades now and are well established in terms of service and application.  M2M service providers have long been using existing cellular networks to enable these services delivering applications such as logistics and asset tracking as well as some more recent examples such as in vehicle telematics.

However, the challenge for cellular operators moving forward is how to continue the investment in this space in order to enable the so called IoT revolution – ultimately the success of the cellular industry in M2M depends mainly on addressing challenges affecting cost, power saving and coverage.

Furthermore, with the continuing global growth of M2M installations, the reliance on existing GSM networks will present a dilemma for mobile operators who will need to re-farm frequencies to gain greater spectrum efficiency and consolidate other access technologies; at this regard decommissioning of 2G mobile network services in the US has already started, with existing customers being moved over to LTE.  Also, other wireless operators without access to 2G spectrum allocation will increasingly see LTE as the future-proof option for M2M.

To help operators wishing to make this transmission, standards body, 3GPP, has been working on defining a new profile of LTE in the forthcoming Release 12 specification. The profile is termed ‘Category 0’ (Cat-0) and promises to address the major challenges facing operators and open LTE for IoT.

Overview of LTE Cat-0

The introduction touched upon the three main limitations that can affect the percentage of cellular connections in M2M and ultimately the success of the cellular industry in M2M:

  • Cost is a key enabler of many M2M applications: cellular has to compete with other long range systems where the cost of the devices has been set below $5.

  • Power saving is of great importance since many M2M devices are battery powered, the deployment and      maintenance costs implied by reduced battery life has a significant impact.

  • Coverage improvements are also required as there is a substantial market for the use cases of M2M devices deployed deep inside buildings3GPP has addressed these M2M device (‘User Equipment’ or UE) challenges with a specific work item for complexity reduction (and in turn thus allow cost of devices to be reduced) and enhanced coverage of MTC devices in LTE, which is part of Release 12 and subsequent specification work.

In particular a ‘low complexity User Equipment’ is being specified in Release 12, whereas a MTC UE can identify itself to the network as a Cat-0 User Equipment. This type of UE can be developed at lower cost, whilst still providing capability to support low latency and data rates of up to 1Mbps appropriate for the vast majority of M2M applications. Release 12 will also introduce new power saving modes enabling MTC devices to go into deep sleep mode when not requiring active communication with the network.

In Release 12 it is defined that the Cat-0 MTC modem is characterized by:

  • One Rx/Tx antenna only (single RF Chain)

  • Peak rate reduction to 1Mbps in downlink and uplink, via reduced transport block sizes

  • Half duplex capability

3GPP estimates that the cost reduction measures of Release 12 can bring down the bill of materials (BoM) of a Cat-0 LTE module by about 50% relative to a single band Category 1 LTE module.

The importance of Cat-0 for IoT in LTE for network operators

The specification of the new category (Cat-0) for MTC has been largely driven by mobile operators with Vodafone acting as the Rapporteur in the 3GPP standards organization.

This is not surprising because from an operator’s perspective LTE is where most significant future investment will reside: it is the technology of choice for wide-area cellular communications delivering the best mobile broadband experience for customers and it is the most spectrally efficient technology, which enables operators to extract most value from their spectrum. This improvement in spectrum efficiency will continue to drive the re-farming of a proportion of GSM spectrum to LTE and it is therefore important LTE is evolved to also fully address the requirements of machine-to-machine (M2M) communications.

As previously discussed, many M2M requirements are well served today by GSM/GPRS which has been cost optimized over several decades of operation and will remain as an important technology offering for many years to come. For LTE to gain significant market share from GSM/GPRS it is imperative to minimize cost and include only the essential capabilities of LTE.

The Cat-0 introduction is an important step that will accelerate this transition, offering suppliers of M2M modules the opportunity to develop products at much lower cost than existing solutions. Combined with the increasing economies of scale associated with LTE deployments around the world, the likelihood is that LTE MTC will become the dominant form of machine connectivity for devices requiring good quality, reliable, low-latency, communications up to 1Mbps.

For operators, this transition towards LTE with the improved performance (relative to GSM/GPRS) will enable a range of new services to be associated with machine connectivity and customers will be less constrained with data rates which are typical in GSM/GPRS  (less than 20kbps on average). As just one example, the data available from a car’s energy management system can become very large and it may be unrealistic to use a GSM/GPRS modem to transfer much of the data that is available. The integration of a Cat-0 LTE module will enable a cost-effective solution for the transfer of larger payloads, enabling cloud-based services to process the data and for operators.

ARM is excited to be involved in this area of connected devices – helping device vendors and semiconductor companies develop market leading next generation devices ready for the cellular connected Internet of Things – and is looking forward to seeing the upcoming changes this new LTE standard and what it will mean in terms of device design and the opportunities it will bring to network operators.


ARM_David MaidmentDavid Maidment is Mobile Segment Marketing Manager at ARM where he looks at the application of ARM technology in the mobile space areas including wearable devices and mobile platforms.

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