Courtesy: u-blox
The Web of Issues (IoT) ecosystem in the present day
The IoT ecosystem is experiencing a revolutionary section. Most Cell Community Operators (MNOs) have introduced and even executed the switch-off of legacy 2G and 3G mobile applied sciences, migrating the associated frequencies to 4G or 5G networks. Consequently, IoT builders should additionally undertake a brand new mobile customary.
Though 5G is already beneath deployment, its use faces a number of challenges. Apart from limitations in international protection, present 5G options don’t meet most IoT necessities: excessive energy consumption, price, dimension, and design complexity are among the drawbacks. 5G RedCap and MMTC are anticipated to handle these points sooner or later. For now, 4G LTE is the one mobile expertise that gives ubiquitous international protection and might play this function for a minimum of the following 5 years.
A bipolar panorama
In 2016, 3GPP Rel 13 specified new 4G mobile requirements for the IoT. The purpose was to compete with non-cellular Low Energy Huge Space (LPWA) applied sciences, like SigFox or LoRaWAN. The brand new mobile requirements that 3GPP launched have been NB-IoT (aka LTE Cat-NB), LTE-M (aka LTE Cat-M), and LTE Cat 1bis (3GPP Rel 8 had already specified the LTE Cat 1 customary).
Following 3GPP Rel 13, MNOs and chip producers targeted on NB-IoT and LTE-M, leaving apart LTE Cat 1bis. This resolution was made as a result of, evaluating specs, the Cat 1bis professionals/cons ratio was much less beneficial than the opposite two.
An intense debate arose across the new proposed mobile LPWA applied sciences for the IoT. One facet pushed towards utilizing NB-IoT, whereas the opposite towards LTE-M as up to now, international locations might independently agree on deployed expertise, supported bands, and roaming agreements.
However aside from just a few exceptions like IMT-2000’s early rollout in Japan or the preliminary deployment of CDMA/EV-DO in North America earlier than converging to UMTS/HSPA, the world was beneath international convergence.
Extra just lately, that convergence was overlooked of the image. APAC and most of EMEA selected NB-IoT implementations, whereas the Americas, Japan, South Korea, and Australia selected LTE-M.
The divergence created a bipolar world. China pushed arduous for NB-IoT; certainly, China is the one nation the place NB-IoT has had an enormous deployment. North America, then again, deployed LTE-M shortly. Right now, LTE-M dominates most of this market, though some MNOs have added NB-IoT assist over time. EMEA’s case is peculiar. Initially, it opted for NB-IoT. Later, nevertheless, most MNOs in Western European international locations additionally added LTE-M assist.
Whereas LTE-M traits match most IoT necessities, this isn’t true for NB-IoT. Even when NB-IoT has higher MCL (Most Coupling Loss) than LTE-M, its knowledge fee is proscribed. As well as, the design of NB-IoT infrastructure doesn’t assist mobility (handover) and voice.
Within the present state of affairs, we discover areas the place IoT purposes profit from wonderful LTE-M protection (like North America), whereas in others, it’s partially or solely absent. When the latter scenario occurs, NB-IoT can not fulfill most use circumstances as a result of abovementioned limitations.
In Europe, many IoT purposes nonetheless hook up with legacy 2G (the place out there). Clients ask for LPWA modules with 2G fallback as a result of LTE-M protection is unreliable and, in worst circumstances, absent. NB-IoT capabilities don’t fulfill use case calls for.
Till just lately, LTE Cat 1 was the lowest-cost 4G mobile expertise with international protection. A downside of LTE Cat 1 is that its chipsets price way more than these for NB-IoT or LTE-M. Furthermore, an LTE Cat 1 design is extra complicated and requires further elements in comparison with LTE-M and NB-IoT, which considerably impacts the general price.
This example has led IoT builders and MNOs to seek for cost-effective options and thus assure LPWA worldwide connectivity, mobility, and roaming for the IoT ecosystem — leading to a renewed curiosity in LTE Cat 1bis.
What’s Cat 1bis?
In a nutshell, LTE Cat 1bis is LTE Cat 1 with a single obtain (Rx) antenna. All the opposite gadget traits, like uplink (UL) / downlink (DL) knowledge charges and protocols, stay the identical. Quite the opposite, customary LTE Cat 1 (3GPP Rel 8) helps Rx range and requires two Rx paths.
Rx range improves RF reception capabilities, particularly on the fringe of the cell. However to assist Rx range, the LTE Cat 1 chipsets require two RF inputs with a classy RF front-end and particular software program. To some extent, this is the reason LTE Cat 1 chipsets price greater than these for LTE-M and NB-IoT, and why LTE Cat 1 purposes require extra elaborated and in depth PCBs, further elements, and two antennas. All these options lead to greater prices: an LTE Cat 1 resolution might price twice as a lot as its LTE-M counterpart.
Eradicating the Rx range function from the LTE Cat 1bis customary permits less complicated, cost-optimized chipset designs. Builders are making the most of this to design less complicated, smaller, and cheaper IoT purposes than they may with the LTE Cat 1 customary.
Why take into account LTE Cat 1bis as a further choice for LPWA?
- Evaluating LTE-M and LTE Cat 1bis, each will be appropriate expertise selections for IoT purposes, relying on the area and use case. There are a number of causes for this:
- Energy consumption: Each LTE-M and LTE Cat 1bis assist low-power modes like PSM and eDRX. These lengthen battery life, an necessary function for a lot of IoT purposes.
- Complete resolution price: Each LTE-M and LTE Cat 1bis can price half as a lot as an equal resolution primarily based on LTE Cat 1, representing important financial savings.
- 5G compatibility: LTE Cat 1bis is a 4G community expertise that connects to the 4G Advanced Packet Core (EPC). In idea, LTE-M and NB-IoT requirements can hook up with the 5G core. But, MNOs haven’t carried out this performance, and none have introduced plans to take action.
- Knowledge fee/latency: LTE Cat 1bis outperforms LTE-M by way of latency and knowledge fee, matching the capabilities of LTE Cat 1 with as much as 10 Mb/s downlink and 5 MB/s uplink. This typically exceeds the necessities of IoT purposes. LTE-M has a downlink restrict of 375 kb/s and an uplink restrict of 1 Mb/s.
To summarize, each LTE Cat 1bis and LTE-M meet the necessities of most IoT use circumstances beforehand served by 2G and 3G applied sciences: medium bandwidth, low energy consumption, and low price, amongst others.
Why take into account LTE Cat 1bis as an LPWA different now? What driving components could lead on IoT builders to ponder LTE Cat 1bis as an LPWA choice? We should take into account the precise use case, worth hole, and standing of LPWA international deployments to reply these questions. When selecting the right communication expertise, 4 issues are at stake. The next is a quick however certainly not exhaustive listing:
- The quantity of transmitted knowledge and the influence on the battery
- Community protection and availability
- Service lifespan
- Hyperlink funds
- Machine dimension
The quantity of transmitted knowledge and the influence on the battery
We should take into account that IoT purposes like video surveillance, alarm methods with video, or eHealth, produce appreciable knowledge quantity. These use circumstances might leverage LTE Cat 1bis operators with 20 MHz bandwidth in comparison with 1.4 MHz for LTE-M.
With extra bandwidth, units can transmit knowledge sooner. This interprets into much less time within the air and, consequently, much less battery utilization. Relying on the quantity of knowledge, sooner transmission means much less time within the air, leading to higher energy effectivity.
Community protection
The worldwide portability offered by legacy 2G and 3G applied sciences is ending as a result of sundown of mobile requirements in lots of international locations. LPWA applied sciences equivalent to LTE-M and NB-IoT have been deployed with out a lot coordination, making a peculiar international scenario. APAC and most Jap European international locations have solely NB-IoT protection, whereas the Americas, Australia, and some European international locations have each NB-IoT and LTE-M. Though on this latter case, the protection faces a number of obstacles.4G LTE is current in most African international locations the place neither NB-IoT nor LTE-M has been deployed. The exception to the rule is South Africa, the place NB-IoT is presently lively.
Roaming agreements must also be thought of. They’re scarce, and there’s no assure that an IoT gadget touring between international locations may have community entry, even when there’s ample protection in each areas.
Contemplate Italy for instance, though this is applicable to different Western European international locations as effectively. Italian MNOs, like most European MNOs, initially deployed NB-IoT. However in latest occasions, Vodafone Italy added LTE-M assist (2022). This doesn’t essentially imply that LTE-M is obtainable all over the place, particularly contemplating that the NB-IoT protection will not be complete. So even when LTE-M is obtainable, the Italian territory lacks full protection with no certainty when this will likely be achieved.
One other instance is america, the place LTE-M has been extensively deployed with good protection throughout a lot of the nation, leading to a big put in base of LTE-M IoT units. But, NB-IoT has been much less prioritized. Though US MNOs have deployed NB-IoT networks, the put in base is far smaller in comparison with LTE-M.
LTE Cat 1bis is obtainable wherever there’s a 4G LTE community, which is the case in most populated components of the world. Roaming between 4G networks is essentially attainable beneath current agreements, making LTE Cat 1bis notably appropriate for cellular purposes equivalent to telematics and asset monitoring. Examples like this might encourage IoT builders to think about LTE Cat 1bis as a viable LPWA choice.
Service lifespan
Presently, it’s tough to say which expertise, LTE Cat 1bis or LTE-M, may have an extended lifespan. The MNOs haven’t introduced any sundown plans for both expertise, and the timing is more likely to range from area to area.
Some markets, like america and a few APAC international locations, might transition to 5G extra shortly. This might incentivize community operators to shift from the present 4G spectrum to 5G. Components to think about might embody the variety of legacy units on their networks, the bandwidth every expertise consumes, and which bands will likely be prioritized for the transition. Different markets, nevertheless, will transfer way more slowly and should maintain each applied sciences alive effectively into the late 2030s.
Hyperlink funds
LTE-M has a Most Coupling Loss (MCL) of -154 dBm in comparison with -149 dBm for LTE Cat 1. LTE Cat 1bis experiences a further 3-4 dB loss in comparison with Cat 1 as a result of absence of the Rx range antenna. Because of this the MCL of LTE Cat 1bis is 8-9 dBm worse than LTE-M. The upper MCL of LTE-M ensures higher connectivity in difficult sign situations, equivalent to harsh city environments, garages, or on the cell edge. Nonetheless, LTE-M’s deeper sign penetration is partially offset by its decrease cell density in comparison with customary 4G LTE.
Machine dimension
Builders discover it arduous to handle some use circumstances, even contemplating the present miniaturization of digital elements. LTE Cat 1 ticks many packing containers to be used circumstances like wearables that require small dimension and medium knowledge charges, providing benefits by way of bandwidth, protection, and energy consumption. Nonetheless, miniaturization has been difficult as a result of want for a dual-antenna design.
The truth that designers purpose for small options forces them to seek out the equilibrium between efficiency and dimension. Consequently, many present small kind issue LTE Cat 1 designs omit Rx Variety and don’t embody a second antenna.
With its simplified antenna, shorter components listing, and extra affordability (in comparison with LTE Cat 1), LTE Cat 1bis may also exchange LTE Cat 1 in lots of use circumstances.
Conclusion
Each LTE Cat 1bis and LTE-M are appropriate expertise selections for LPWA purposes. So earlier than making a selection, one should take into account expertise traits and regional deployment. One could also be a greater candidate than the opposite, or perhaps each could possibly be thought of. u-blox can help with this sort of choice, relying on particular use circumstances and MNOs.
u-blox presents a broad portfolio, together with LTE-M, LTE Cat 1, and LTE Cat 1bis modules. u-blox established early market management in LTE-M with the primary licensed LTE-M module sequence, SARA-R4, which additionally presents 2G fallback. u-blox additionally developed its personal LTE-M chipset, the UBX-R5, which was used as the premise for the u-blox SARA-R5 module sequence. Each sequence have been additional miniaturized into the LEXI-R4 and LEXI-R5 kind components.
For LTE Cat 1bis, u-blox presents the LENA-R8 and LEXI-R10 sequence. LENA-R8 can also be out there as a combo: LTE Cat 1bis + GNSS variant. The GNSS core is the brand new u-blox M10 GNSS platform. The LENA-R8 combo (LENA-R8M10) has two energy provides, offering clients with wonderful energy administration flexibility, thus optimizing the general efficiency. LEXI-R10 is the world’s smallest LTE Cat 1bis module supporting Wi-Fi scanning and CellLocate for indoor positioning. The u-blox LARA-R6 LTE Cat 1 module helps full Rx range and is greatest fitted to high-performance purposes.
