IoT, M2M Will Lean on Platforms Using Unlicensed Spectrum

source: Verizon Communications

As important as licensed spectrum has been for development of mobile services, unlicensed spectrum is shaping up as a more-important access approach.

Verizon Communications has committed to introduce Long Term Evolution using unlicensed spectrum, even before the formal standard has been ratified.

LTE in unlicensed spectrum allows mobile service providers to bond capacity supplied by licensed and unlicensed spectrum.

The other important development is the Internet of Things, especially many machine-to-machine sensor apps that require extremely low-cost devices with long battery life, wide area communications range and low-cost network platforms as well.

So it is that the LoRa Alliance, including firms such as IBM, Cisco and Microchip Technology, as well as telecom operators Bouygues Telecom, KPN, SingTel, Proximus, Swisscom, and FastNet (Telkom South Africa), supports the use of LoRa spread-spectrum radio protocol for use in wide area networks and the Internet of Things.

LoRa (Long Range) is a low data rate, long-distance communication protocol used by Semtech Corp. to provide industrial, home and building automation networks. LoRa supports devices with a range of up to 50 kilometers. The long range means that large areas can be covered by relatively few base stations.

Just as significantly, LoRa devices are expected to operate for as long as 10 years without a battery swap.

That is part of the reason supporters believe LoRa has value for many IoT and M2M applications.

Separately, SigFox uses an ultra-narrow-band platform for machine-to-machine communications and IoT, also operating in unlicensed spectrum.

The base stations are said to operate over ranges of three to 10 kilometers in urban areas and up to 30 to 50 kilometers in rural areas.

To be sure, mobile service providers have numerous tools available to them to increase network capacity, ranging from exclusive spectrum resources to traffic offload to network architecture to improvements in air interface technology.

So despite the importance of licensed spectrum, other sources of leverage, including unlicensed spectrum and network elements, technology and architectures, are becoming equally important.

And at least as Verizon Communications positions the matter, the cost of acquiring new spectrum is growing, while the cost of network enhancements is dropping.

Without question, mobile service providers prefer to supply capacity by gaining the use of new spectrum, largely because that has been “an extremely cost effective means of adding capacity,” according to Tony Melone, Verizon Communications CTO.

But Moore’s Law and manufacturing volume matter. So the cost of relying on a technology-driven solution (smaller cells, better radios, antennas and modulation protocols) are going down every year, Melone also said.

That probably does not mean capacity gains are equivalent, using either “new spectrum” or “network technology” approaches. It likely remains the case that additional spectrum remains a cheaper way to gain new capacity.

source: Verizon Communications

But Long Term Evolution, eventually 5G, antenna technologies and interference management techniques are playing a crucial role.

“All of these technology solutions will drive improvements in bits per hertz and cost per bit,” Melone said.

The latest technique is use of LTE protocols over unlicensed spectrum. “With our key suppliers we are active in the standards process and will likely deploy a pre-standard version in the not too distant future,” said Melone.

Unlicensed spectrum might play a key role supporting Internet of Things networks especially focused on industrial, agricultural, utility and environmental sensor applications.

Such applications typically require low power platforms of low cost, but able to transmit messages at reasonable distances.

SigFox claims to have a network providing 80 percent coverage of France and has signed up operators in the Netherlands, Spain, UK and Russia, and is working on satellite connections as well.  

The point is that, if one assumes the next big leap in mobile and untethered communications will be to support machines, not people, then unlicensed spectrum is likely to play a bigger role.