LTE stands for Long Term Evolution, which includes a steady stream of new 3GPP standards designed to meet the unique requirements of IoT applications. How can device OEMs, systems integrators, and enterprise users decide which one is the best fit for their particular use case?
Start by considering your application’s top requirements for speed, device cost, power, coverage, and longevity. For example, many IoT applications are low bandwidth and require affordability, long battery life, and the ability to remain in service for five years or longer. Those are a good match for low-power wide-area (LPWA) technologies known as LTE Cat M1 and LTE Narrowband-IoT (NB-IoT).
NB-IoT: Broad Applicability and Availability
As its name implies, NB-IoT uses a narrow slice of spectrum, which helps reduce device costs, making it a good fit for price-sensitive applications such as asset trackers, pet trackers, utility meters, and agricultural sensors. NB-IoT debuted as part of 3GPP Release 13 and initially supported maximum downlink speeds of 21 kbps and 62.5 kbps uplink. Release 14 increased those speeds to 120 kbps and 160 kbps, respectively.
Those relatively low speeds are one of the ways that NB-IoT maximizes battery life. Applications such as tracking and sensing aren’t continually uploading large amounts of data. Instead, their devices can transmit a few kilobytes and then put themselves in low-power mode for a few minutes or a few hours. Module vendors say that up to 10 years of battery life is possible when a device is designed to take full advantage of NB-IoT’s power-saving features, which include extended Discontinuous Reception (eDRX), Power Saving Mode (PSM), and RRC Inactive (RAI).
Mobile operators can easily support NB-IoT with their existing infrastructure, which is why NB-IoT service is widely available in North America and the rest of the world. This is important for devices that will travel around a country, continent, or the planet — such as shipping container trackers — because roaming is available. It’s also valuable for developing applications that can be sold in multiple countries and continents.
Cat M1
Cat M1 is a good fit for IoT applications that require more bandwidth (up to 1 Mbps), lower latency, and other capabilities that NB-IoT doesn’t support, such as Voice over LTE (VoLTE). It also supports eDRX and PSM but prioritizes speed over battery life compared to NB-IoT.
If an application’s devices move frequently, Cat M1 is a better option because it’s designed to accommodate more mobility than NB-IoT.
Cat M1 and NB-IoT both have extensive coverage, including via roaming. For a continually updated map of Cat M1 and NB-IoT networks worldwide, see https://www.gsma.com/solutions-and-impact/technologies/internet-of-things/deployment-map.
Operator Performance Requirements
Mobile operators frequently allocate certain bands for each type of technology. For example, AT&T requires LTE NB-IoT devices to have modules and antennas that support bands 24 and 12.
Operators also have performance requirements — measured in total radiated power (TRP) and total isotropic sensitivity (TIS) — that Cat M1 and NB-IoT devices must meet in order to use their networks. These requirements tend to be less stringent than those for “full” LTE.
The following example is AT&T’s requirements for a Cat M1 device with a form factor under 107 mm in the longest direction. AT&T allows these devices to have an antenna efficiency 8 dB lower than devices with a form factor larger than 107 mm.
AT&T also requires only one antenna for Cat M1 and NB-IoT devices versus two for Cat 1. This enables device designs that are lower in both complexity and cost, which are major benefits for the types of IoT applications that can use LPWA technologies
The PCS.55.A provides a simple off-the-shelf solution for LTE, LTE CAT-M, NB-IoT, and GNSS applications. This compact, patent-pending cellular antenna is ideal for IoT devices that are continuously becoming smaller. It requires a relatively small keep-out area compared to most other compact cellular antennas on the market, thanks to Taoglas’ extensive expertise in antenna design. For customers with limited space on their boards, the FXUB53 offers a “peel and stick” flexible wideband antenna. It has been designed to cover all operating frequencies in the 600-6000 MHz spectrum. This includes all 5G and 4G cellular bands, with fallback support for 3G and 2G, as well as NB-IoT, Cat-M, Wi-Fi®, and ISM bands. With a super small footprint of 120x20mm, it addresses the size constraints often encountered when integrating high-performance antennas into compact IoT devices. The FXUB53 can be directly mounted onto plastic enclosures or glass surfaces.
All of this is a lot to consider, which is why savvy device OEMs, systems integrators, and end users turn to a trusted expert that can provide insights into standards evolution, operator roadmaps, and other key factors. To learn more about how to select the right antenna, speak to Taoglas’ Engineering team by clicking on the button below.
