There are lots of technology choices for IoT connectivity, maybe too many, but no single one is optimal for all use-cases. They all come with pros and cons where some of the cons can de-rail an IoT project completely.
Summary
Which are the IoT connectivity technology options on a high levelIt’s imperative to understand how to select the best possible IoT connectivity technology for your IoT projects. At the core, it’s a compromise between cost, coverage, power consumption, availability of technology (both hardware as well as support in the networks) and capacity. This article introduces a framework where questions in 5 groups need to be answered for the IoT project and then helps identifying the most suitable technology options.
Which are the IoT connectivity technology options on a high level?
Below is a subset of the technologies I run across most frequently for various IoT use cases. I’ve divided them into four groups, predominantly based on the underlying delivery technology, see figure 1.
Figure 1 - High level IoT Connectivity Technology Options (partial list)
Let’s look at the options in a bit more detail:
3GPP standards over LTE
- About 800 operators support LTE across 240 countries and territories
- Cat-1 was part of the original LTE standard, Rel 8 back in 2008, which means it works in all existing LTE networks. Cat-1bis (introduced in R13 in 2016) is a version that only requires 1 antenna which reduces cost and footprint. Cat-4 is a higher speed module (also part of R8).
- NB-IoT (NB stands for NarrowBand) and LTE-M are LPWA (Low Power Wide Area) technologies introduced in R13 in 2016 (The GSMA uses the term MIoT [Mobile IoT] that refers to the LPWA technologies using licensed bands). Some LTE functionality have been removed and new things added to optimize for low power and improved indoor/underground coverage. NB-IoT is supported (at time of writing, May 2024) by 133 operators across 67 countries and LTE-M is supported by 61 operators across 39 countries. Increasingly operators support both technologies in their networks and the number of operators supporting the technology has started to grow at a faster pace.
- LTE is expected to be around until at least 2035 in most regions, possibly with the exception of North America.
3GPP standards over 5G
- About 300 operators support 5G across 120 countries and territories of which about 50 have deployed SA (Stand Alone)
- NB-IoT and LTE-M has been carried forward unchanged into the 5G standards and leading 5G operators like T-Mobile in the US have switched services on nationwide in their 5G SA network.
- 5G NR (New Radio) is really a “standard” 5G modem
- RedCap, introduced in R17 in 2022, stands for Reduced Capabilities and is an upcoming technology in 5G to offer some of the LPWA advantages but at higher speeds. Probably ready for adoption in late 2025/early 2026. Currently, 4 operators support RedCap in their commercial networks (3 in mainland China and one in Kuwait). A 5G SA network and a 5G core is a prerequisite for an MNO to support RedCap. Most operators with a 5G SA networks will state that they will be supporting RedCap, but not providing any official timelines. The RedCap ecosystem is still nascent with only 2 RedCap chipsets and less than 20 IoT modules supporting RedCap. As with all nascent technologies, the cost of modules is high ($50+) but expected to drop as volumes increase.
3GPP standards over Satellite
- 5G – NTN stands for Non-Terrestrial-Networks, i e Satellite, and was introduced in R17 and is an emerging technology. In effect, this is running NB-IoT over satellite and suitable for message oriented traffic patterns. About 50 operators have announced plans and about 10 have launched 5G-NTN services.
Non-3GPP standards
- LoRaWan is the most common one but there are others like Wi-SUN and 5G NR+. LoRaWan networks can be public, private or hybrid. There is currently 180+ operators of public LoRaWAN networks.
Complicating factors
Not all operators will implement all the standards in their networks, nor all aspects of the standard. Sometimes operators may have limitations like dual vendor networks that don’t permit simultaneous rollout across an entire country or shared networks with other operators.
eSIM and iSIM is not fully supported by all technologies until the eSIM standard SGP.32, that was published in May of 2023, is implemented which is expected to happen by end of 2024 across the ecosystem. In the previous standard, there was multiple ways to download an eSIM profile, the low tech way was via SMS, which is a problem with NB-IoT that don’t normally support SMS.
2G and 3G was the last standards where there were global harmonization of frequencies used. Starting with LTE, there are many more frequency bands that can be used. To keep module cost affordable, there is frequently regional versions of a module that is optimized to work in a certain region. Not all modules are truly global and the ones that are, come with a premium.
The questions you need to be able to answer in order to select the best technology options
In figure 2 below, there are 11 base questions divided into 5 requirements areas that needs to be answered in order to identify the relevant technology choices.
Figure 2 – Questions to answer in order to select best technology options
Looking at the questions in more detail:
Module Location –
Geographic Footprint – Roaming is nascent when it comes to NB-IoT, somewhat better when it comes to LTE-M. LTE Cat-1 is covered by “every” LTE roaming agreement in place between MNOs. For use cases that requires complete in country coverage or close to global coverage, 5G NTN is the only option.
Module Mobility – NB-IoT was designed for stationary devices and don’t support switching to a new cell if the device is moving. This is changing in NB2 but at low speeds. LTE-M and LTE Cat-1 have full support to move to a new cell when the device moves, even at high speeds like the rest of the technologies.
Location - Both LTE-M and NB-IoT have better coverage compared to other technologies due to different modulation and repetition. This becomes very visible when the device is deep indoor or underground. Most operators typically put NB-IoT in the best possible spectrum so in real life situations NB-IoT typically have an advantage over LTE-M. 5G NTN that uses satellites have a requirement of free line of sight to the satellite(s).
Application Requirements -
Bandwidth Requirements - NB-IoT operates in GPRS (2G data) like speeds 26 Kbps downlink and 17 Kbps uplink theoretically (single-tone). LTE-M is significantly faster with 1 Mbps in both down and uplink theoretically. LTE Cat-1 is even faster technology with 10 Mbps downlink and 5 Mbps uplink theoretically, enough for streaming video. LTE Cat-4 and RedCap can deliver even higher bandwidths. LoRaWAN is roughly equivalent to NB-IoT. 5G NTN is really running NB-IoT over Satellite with limitations on packet size and number of packets per minute.
Latency Requirements - NB-IoT have a typical latency of > 1.6 seconds. LTE-M and LTE Cat-1 as well as the other LTE and 5G technologies have “traditional” LTE latency around 50 milliseconds or lower. 5G NTN typically have a latency between 5-50 seconds.
Text Requirements (SMS) - Although it’s technically possible to support SMS over NB-IoT, hardly any MNOs support it currently. Most operators support SMS over LTE-M and when it comes to LTE Cat-1 and other 3GPP technologies, it’s a mandatory part. SMS is the low-tech way to get an eSIM profile onto a device with the current eSIM standards.
Voice Requirements - Voice in an LTE (as well as 5G) network is packetized and the standard is called VoLTE (Voice over LTE) and VoNR (Voice over NR). VoLTE is not supported in NB-IoT. VoLTE is part of the LTE-M specification but not all operators support it. VoLTE is a mandatory part of LTE Cat-1 and other LTE technologies.
Timing Requirements -
• Deployment Date – For large scale deployments before 2026 the only realistic alternatives are LTE based technologies, 5G NR and LoRaWAN as RedCap and 5G NTN is still very nascent technologies. Normally it takes at least 18-24 months after a standard is ratified until there is HW and MNOs supporting the new technology.
• Deployment Duration – The only two LTE based technologies that will gracefully migrate into a 5G network when the current LTE networks will be decommissioned in 2035 and beyond are NB-IoT and LTE-M.
Power Requirements – The technology that typically consumes the least energy in PSM (Power Save Mode) is NB-IoT that can consume less than 1 microamp. LTE-M modules typically consume 1.5 – 1.8 microamps. A typical LTE Cat-1bis module in sleep mode consumes 160 microamps, that is 200 times what a NB-IOT consumes. 5G NTN is significantly more power hungry due to higher output levels needed to communicate to satellites. LoRaWAN is very comparable to NB-IoT.
TCO - Module Cost – The cost of the IoT module is a significant part of the TCO together with the cost of communication. Module cost for a certain technology tend to go down over time as volumes go up. At the time of writing this article NB-IoT modules are typically well below $10 in volume while RedCap modules can cost more than $50. There are “combo” models available from many of the IoT module manufacturers that support e g both NB-IoT (typically NB2) and LTE-M (typically M1) which offers greater flexibility and geographic coverage as it can switch depending on requirements and network availability. There also modules that can combine terrestrial technology with 5G NTN for maximum coverage but using the least costly option to communicate.
Future evolution of some of the technologies
The next version of NB-IOT is formally named LTE Cat NB2 and offers higher throughput of 127 Kbps down and 159 Kbps up theoretically, better positioning and the ability to move between cells at low speed (introduced in 3GPP release 14).
The next version of LTE-M is formally named LTE Cat M2 and offers higher throughput of 4 Mbps down and 7 Mbps up theoretically (introduced in 3GPP release 14).
The next version of LTE Cat-1 is named LTE Cat-1bis and basically offers identical performance as LTE Cat-1 but using only one antenna which lowers the price and reduces the size of the module (introduced in 3GPP release 13). LTE Cat-1bis is designed to work on any existing LTE network without changes.
In 3GPP release 18, eRedCAP was introduced. eRedCap is expected to be available in the 2027 timeframe and is not a direct replacement of RedCap, more like a lower speed/lower cost module with similar characteristics as LTE Cat-1
A framework to facilitate technology selection
Figure 3 shows a framework that can be used to identify the best technology candidates for your IoT projects. You have all the questions above on the left-hand side together with answers. There are dots for each technology that meets that specific answer. Select the answer that is applicable for your project, mark the row with a highlighter pen on a printout or electronically on a softcopy. Continue until you selected one answer for each question.
Figure 3 - Framework for IoT Connectivity Technology Selection
When your answers are selected, next look at which columns have a dot in each one of the highlighted rows and you’ve identified the candidate technologies (see figure 4 for an example of a typical water meter use case).
Figure 4. Example of a typical water meter use case
The sweet spot for the different mature technologies can be summarized as:
No external power source and stationary position deep indoors or underground is usually a good candidate for NB-IoT or a dual mode module that operates on NB-IoT most of the time and can switch to LTE-M for SW and FW OTA (Over The Air) upgrades. Sensors in water and sewage mounted underground would be a great example.
No or limited external power source, moving around at modest speeds, requirements for voice and SMS, support for eSIM in a limited footprint. Typically a good candidate for LTE-M.
External power source, requirements for a large and unpredictable footprint, moderate to high data rates, eSIM, voice and SMS support. Typically a good candidate for LTE-Cat1 and Cat1-bis as well as 5G NR and higher LTE-Cat standards. Track and trace of trucks, trailers and construction equipment would be a great example.
Where to seek additional guidance on technology selection
Engaging with a knowledgeable 3rd party to ensure the optimum technology is selected for the specific use-case and its footprint is a best practice. These 3rd parties can be found in these four categories of organizations:
IoT connectivity service providers like leading MNOs and MVNOs (Mobile Virtual Network Operator) with a strong IoT practice can advise on technology selection and know exactly the capabilities of their local OpCos and respective roaming partners on a country-by-country basis. In addition, they usually have a sizeable ecosystem of vertically aligned partners. Some of them can also project manage complete pilots or production roll outs.
IoT Module Manufacturers like Quectel, Semtech/Sierra Wireless and Telit/Cinterion to name a few.
SIs (System Integrators) with sizeable IoT practices
IoT focused Technology Advisory organizations like Transforma Insights, Berg Insight and Lionfish Tech Advisors to name a few.
Recommendations
The main success factor is to fully understand the use-case(s) and how they’ll evolve from a functional as well as geographic perspective over time. Once you have each use case described:
Map it to the optimum technologies using the framework and take into consideration the dual mode modules that exist on the market as well as potentially combine more than one module.
Validate the technology selection using 3rd party organizations that can ensure that operators in the desired footprint can support the required functionality.
Factor into the decision that a single truck roll to fix a problem in production may change the TCO calculation dramatically. In many situations, it may be prudent to go with a slightly more expensive module that have more capabilities.
If you have the power budget for a LTE Cat-1 module, it’s usually the most versatile and “safe” bet when you need you have a multi country footprint.
Sources
This article is based on publicly available information from mobile operators, IoT module manufacturers and the GSA (Global mobile Suppliers Association) as well as my own analysis.
----- ----- ----- ----- ----- ----- -----
Byline
Leif-Olof Wallin is an independent Tech Advisor that specializes in Enterprise Mobility, Frontline Workers, Private Mobile Networks and IoT. Formerly, he was one of the Gartner analysts that published most of the Gartner research around IoT and what happens in the intersection of IoT, advanced analytics and Frontline Workers. LinkedIn: https://www.linkedin.com/in/leifolofw/
----- ----- ----- ----- ----- ----- -----