Wireless connectivity for the Internet of Things (IoT) will use many network access technologies, including cellular LTE. Distributed antenna systems (DAS) provide strong and reliable cellular connectivity inside buildings, and so will be important for ensuring availability of LTE-based IoT services in the coming years
LTE for the IoT
There are plenty of other wireless protocols and air interfaces available for supporting IoT applications (Bluetooth, LoRa, ZigBee, and Z-Wave, to name a few), but it’s clear that LTE will dominate plans for supporting the IoT. This is primarily because cellular networks today are both robust and ubiquitous. The trend towards use of LTE as the primary transport for IoT applications is already apparent, as global cellular IoT connections reached almost 261 million at the end of 2015 and are forecasted to approach 1.22 billion in 2021, according to a recent study by Beecham Research. In addition, Machina Research projects that there will be 2.2 billion LTE-based IoT endpoints by 2024. Finally, ABI Research predicted earlier this year that LTE M2M cellular modules will grow to more than 50 percent of total module shipments by 2021, with much of that growth being driven by businesses and consumers in North America.
Compared to previous LTE specifications, Category M1 is designed to cost-effectively address cellular connectivity for low data rate IoT applications across a wide range of new business opportunities within the IoT, including smart energy and metering, building security, infrastructure, industrial control and automation, retail point of sale, asset tracking, medical, lighting and aftermarket telematics. Verizon announced plans to deploy LTE Category M1 by the end of the year, claiming it will become the first U.S. operator to launch the new technology. AT&T announced a pilot in the San Francisco Bay Area starting in November. Category M1 is an IoT-centric flavor of LTE that uses 1.4 MHz of spectrum to deliver 300 kbps to 400 kbps. It appears to resemble a 2G GPRS connection but supports a device battery life of 10 years or longer, and is designed to connect sensor applications and devices requiring lower throughput.
While some of the IoT applications will be outdoors (connected cars and trucks or street lighting infrastructure, for example), most IoT applications will be within buildings. Industrial control, point of sale, asset tracking, medical, environmental monitoring, security, smart lighting, and other applications will require strong in-building wireless signals. Ideally, the wireless network solution should deliver seamless blanket coverage throughout the building so as not to restrict where IoT sensors can be placed. It should also support multiple frequencies, because mobile operators use 700 MHz, 1900 MHz, and AWS frequencies for LTE. Finally, the solution should support time division duplexing (TDD) as well as frequency division duplexing (FDD) because mobile operators will use both technologies in their networks.
A distributed antenna system (DAS) is a strong candidate for an in-building wireless solution because it meets the above criteria. DAS offers single-zone wireless coverage in a building: unlike small cells, it isn’t subject to inter-cell interference and handoffs from one coverage area to another as devices move through a building. In addition, DAS infrastructure natively supports multiple wireless frequencies. Finally, some DAS support both TDD and FDD transmission schemes, whereas today’s small cells do not.
There are many DAS solutions on the market, but by meeting a few key requirements, network managers and building owners can make an effective decision when choosing one.
Multi-frequency support. Some DAS products are frequency-specific, and it is a complex matter to specify and order components that support all of the needed frequencies. It’s best to look for a DAS that supports all frequencies currently in use within a single system. Ideally, the DAS should natively support a broad selection of frequencies.
TDD and FDD capabilities. The DAS should support both FDD and TDD technologies. Not all DAS solutions do.
Simple design. A DAS shouldn’t require a group of high-priced specialists to install. Instead, it should have components and a design that’s similar to Wi-Fi and therefore familiar to most IT technicians.
Ease of installation. Upgrading a building for wireless IoT support can be a disruptive process. Some DAS use heavy coaxial cabling that requires special installation expertise, for example, while other systems use all-fiber transport architecture. Fiber is thin and light, and is much easier and more economical to pull above ceilings than other cabling media.
Low TCO. A DAS is an investment that must stand up over time, so it’s important to look for solutions that have a low total cost of ownership (TCO). Every few years, cellular carriers add new frequencies to their services, and these must be accommodated as cost-effectively as possible. Some DAS products must be upgraded with additional hardware every time a new frequency is added, while other products natively support a wide range of frequencies without upgrades.
The IoT is coming quickly, and mobile operators will be looking to leverage their LTE networks to support it. By deploying a DAS, building owners can ensure robust support for LTE-based IoT within their facilities and be positioned to deliver critical wireless services now and in the future.
John Spindler is VP Marketing and Product Management at Zinwave, a global provider of wideband active distributed antenna system (DAS) technology. He has over 30 years of product management and marketing experience in the wireless and telecommunications industries, most recently serving as Director of Product Management with TE/Commscope and VP Marketing at ADC Telecommunications before joining Zinwave.
Filed Under: Infrastructure, IoT • IIoT • internet of things • Industry 4.0