Cellular IoT: An Opportunity for Billions of New Deployments

"The internet will disappear. There'll be so many IP addresses, so many devices, sensors, things that you simply are wearing, things that you are interacting with, that you won't even sense it. it'll be part of your presence all the time. Imagine you walk into a room, and also the room is dynamic. And with your permission and all of that, you're interacting with the things going on within the room." -Eric Schmidt, former chief executive officer of Google.

The demand for LTE-based Internet of Things (IoT) connectivity continues to gain momentum alongside the increasing need for connected equipment. According to Ericsson (2018), there'll be more than 3.5 billion cellular IoT devices in the market by 2023, creating cellular technology a major communication enabler of IoT.

There are a variety of competing technologies on the market to connect IoT devices. many of the wide-area technologies, like Sigfox, Weightless, and LoRa, aren't LTE based. that's an important distinction because LTE-based IoT can be overlaid on existing LTE networks as a software upgrade. It's thus much easier-and less costly-for the cellular operators to deploy.

The Advantages of LTE-based IoT

LTE-based IoT (LTE Cat-M and NB-IoT) devices offer a number of benefits over standard 3G and 4G devices: extended battery life, lower cost, and better coverage. Device battery life is extended when the improved signal environment allows devices to transmit at a considerably lower output power. the entire cost of wireless is improved once the solution leverages an existing carrier network; instead of making one with your IT department. this is often not to say Cellular IoT is the most economical for each deployment, however certain types. to explain the better coverage via cellular IoT, there are 2 basic elements to look at:

Link Budget: better coverage is delivered primarily because of the considerably higher link budget, that is a very important measure for power calculation. Link budget calculates the power received at the receiver (device) and accounts for gains and losses on the way. it's used to indicate how weak the signal can be from the tower to the device (and vice versa) for the system to still operate (communicate).

Larger Coverage Capability: Standards bodies have worked to make sure a better link budget for cellular IoT. it's regarding 20 decibel (~ -164 dB) better than standard 3G and 4G technologies (~ -144 dB), ensuring coverage to an area approximately 7x larger (in an open environment). This 20-decibel link budget improvement also leads to better in-building signal penetration.

However, in spite of the improved link budgets and wider coverage areas, LTE-based IoT devices are still subject to the same in-building cellular signal penetration and coverage challenges experienced by any mobile phone user inside the building. A 2017 Zinwave study showed that 74 of workers have "frequent" or "sometimes" bad cellular coverage.

While operators still struggle to provide good in-building coverage from outdoor towers, a business cannot afford to have its mission-critical business functions inoperable "frequently" or "sometimes" because of a poor cellular connection. The impact on non-mission-critical operations might also reduce the general productivity of a company. to take advantage of the benefits of LTE-based IoT, there should be good and reliable cellular coverage throughout a building.

In-Building Cellular Coverage options for IoT

There are 3 ways to deliver coverage indoors to provide the necessary quality of service for IoT: wired to router, wireless mesh, and dedicated cellular signal amplification.

Wired to Router Network

For many applications, this very simple solution will suffice. If the on-premise IoT solution is simply creating use of a wide area, wireless-enabled router or gateway in which the on-site sensors and nodes are connected via wires, then an antenna can be run to the exterior of the building. to provide coverage to a single fixed point, this is a workable option.

However, for the antenna to pick up signal, there must be some service available to the exterior of the building. There also are some limitations around equipment placement-the antenna run can't be too long because of the attenuation of the signal over the length of the coax cable.

Wireless Mesh Network

Some IoT networking technologies implement a variety of mesh capability, allowing for a 'string of pearls' style approach to coverage. During this model, each network node becomes both a sensor and a gateway for other devices.

Some applications will leverage this capability quite well. 802.15.4 (Zigbee) is one such networking technology that produces use of mesh capability. However, there are 2 main weaknesses with this approach in extending the IoT network and coverage.

First, as a result of each node becomes a full-time participant in the communications path, they need power all the time. This makes a mesh network very difficult to maintain when relying on battery power. Battery life for a node can decrease from 10 years to solely a few months, depending on where it sits in the network and how often it's used. keep in mind that if a single node goes down in the network chain, all of the nodes after it are incommunicado. this is mostly a non-issue where nodes are powered, as with most smart home applications, for example.

The second issue is latency. each node introduces latency into the network architecture, which might impact message time out and cause issues with real-time applications.

Dedicated Cellular Signal Amplification

Ideally, for IoT implementations, the technology used to amplify the signal merely relays the external coverage internally with delays that are therefore minimal that it's invisible to the cellular network. For mission-critical business solutions that rely on real-time communications, this is often important. Introduction of noise into the system will also negatively impact a network's performance.

Nextivity developed proprietary processors used in their line of Cel-Fi signal amplification systems to address noise and latency concerns. Cel-Fi good signal boosters and active DAS hybrid products offer a network-safe guarantee and are approved by the Federal Communications Commission to boost signal up to 100dB, 1,000 times greater than allowed with wideband BDA repeaters.

Unlike mesh networks, these dedicated cellular signal amplification systems don't do any other work so they will operate once needed, waking only when prompted or on a timer.

Cel-Fi: Enabling Cellular IoT

As the market expands, costs are plummeting, for both equipment and service, and also the ease of installation makes these systems a desirable solution for IoT applications in an exceedingly myriad of industries and applications, such as: construction sites, solar farms, vending machines, oil and gas remote sites, law enforcement, and public safety.