LTE Cat 1bis An possibility for Low Energy Broad Space (LPWA) purposes

Courtesy: u-blox

The Web of Issues (IoT) ecosystem at present

The IoT ecosystem is experiencing a revolutionary part. Most Cellular 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. Because of this, IoT builders should additionally undertake a brand new mobile normal.

Though 5G is already beneath deployment, its use faces a number of challenges. In addition to limitations in world 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 deal with these points sooner or later. For now, 4G LTE is the one mobile expertise that gives ubiquitous world protection and may play this position for at the very least the subsequent 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 Broad Space (LPWA) applied sciences, like SigFox or LoRaWAN. The brand new mobile requirements that 3GPP launched had 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 normal).

Following 3GPP Rel 13, MNOs and chip producers targeted on NB-IoT and LTE-M, leaving apart LTE Cat 1bis. This choice was made as a result of, evaluating specs, the Cat 1bis execs/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 other than a couple of 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 world convergence.

Extra not too long ago, that convergence was omitted 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 a large deployment. North America, however, deployed LTE-M rapidly. 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, nonetheless, 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 information fee is restricted. As well as, the design of NB-IoT infrastructure doesn’t assist mobility (handover) and voice.

Within the present situation, 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 state of affairs occurs, NB-IoT can’t fulfill most use instances as a result of abovementioned limitations.

In Europe, many IoT purposes nonetheless connect with legacy 2G (the place accessible). Clients ask for LPWA modules with 2G fallback as a result of LTE-M protection is unreliable and, in worst instances, absent. NB-IoT capabilities don’t fulfill use case calls for.

Till not too long ago, LTE Cat 1 was the lowest-cost 4G mobile expertise with world protection. A downside of LTE Cat 1 is that its chipsets price rather more than these for NB-IoT or LTE-M. Furthermore, an LTE Cat 1 design is extra advanced and requires extra parts in comparison with LTE-M and NB-IoT, which considerably impacts the general price.

This case has led IoT builders and MNOs to seek for cost-effective alternate 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 system traits, like uplink (UL) / downlink (DL) information charges and protocols, stay the identical. Quite the opposite, normal LTE Cat 1 (3GPP Rel 8) helps Rx variety and requires two Rx paths.

Rx variety improves RF reception capabilities, particularly on the fringe of the cell. However to assist Rx variety, the LTE Cat 1 chipsets require two RF inputs with a complicated RF front-end and particular software program. To some extent, for this 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 intensive PCBs, extra parts, and two antennas. All these options lead to greater prices: an LTE Cat 1 answer might price twice as a lot as its LTE-M counterpart.

Eradicating the Rx variety characteristic from the LTE Cat 1bis normal allows easier, cost-optimized chipset designs. Builders are benefiting from this to design easier, smaller, and cheaper IoT purposes than they may with the LTE Cat 1 normal.

Why contemplate LTE Cat 1bis as a further possibility 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 prolong battery life, an necessary characteristic for a lot of IoT purposes.
• Complete answer price: Each LTE-M and LTE Cat 1bis can price half as a lot as an equal answer 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 connect with the 5G core. But, MNOs haven’t applied this performance, and none have introduced plans to take action.
• Knowledge fee/latency: LTE Cat 1bis outperforms LTE-M when it comes to latency and information 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 instances beforehand served by 2G and 3G applied sciences: medium bandwidth, low energy consumption, and low price, amongst others.

Why contemplate LTE Cat 1bis as an LPWA various now? What driving elements may lead IoT builders to ponder LTE Cat 1bis as an LPWA possibility? We should contemplate the precise use case, worth hole, and standing of LPWA world deployments to reply these questions. When selecting the best communication expertise, 4 issues are at stake. The next is a quick however on no account exhaustive listing:

• The quantity of transmitted information and the influence on the battery
• Community protection and availability
• Service lifespan
• Hyperlink funds
• Machine dimension

The quantity of transmitted information and the influence on the battery

We should contemplate that IoT purposes like video surveillance, alarm programs with video, or eHealth, produce appreciable information quantity. These use instances might leverage LTE Cat 1bis operators with 20 MHz bandwidth in comparison with 1.4 MHz for LTE-M.

With extra bandwidth, gadgets can transmit information 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 similar to LTE-M and NB-IoT have been deployed with out a lot coordination, making a peculiar world state of affairs. APAC and most Japanese 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 at the moment lively.

Roaming agreements must also be thought-about. They’re scarce, and there’s no assure that an IoT system touring between international locations can have community entry, even when there’s adequate 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 in all places, particularly contemplating that the NB-IoT protection just isn’t complete. So even when LTE-M is obtainable, the Italian territory lacks full protection with no certainty when this can be achieved.

One other instance is the USA, the place LTE-M has been extensively deployed with good protection throughout many of the nation, leading to a big put in base of LTE-M IoT gadgets. But, NB-IoT has been much less prioritized. Though US MNOs have deployed NB-IoT networks, the put in base is way 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 present agreements, making LTE Cat 1bis significantly appropriate for cell purposes similar to telematics and asset monitoring. Examples like this might encourage IoT builders to contemplate LTE Cat 1bis as a viable LPWA possibility.

Service lifespan

At the moment, it’s tough to say which expertise, LTE Cat 1bis or LTE-M, can 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 the USA and a few APAC international locations, could transition to 5G extra rapidly. This might incentivize community operators to shift from the present 4G spectrum to 5G. Elements to contemplate could embody the variety of legacy gadgets on their networks, the bandwidth every expertise consumes, and which bands can be prioritized for the transition. Different markets, nonetheless, will transfer rather more slowly and will hold 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 variety 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, similar 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 normal 4G LTE.

Machine dimension

Builders discover it arduous to deal with some use instances, even contemplating the present miniaturization of digital parts. LTE Cat 1 ticks many bins to be used instances like wearables that require small dimension and medium information charges, providing benefits when it comes to 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 search out the equilibrium between efficiency and dimension. Consequently, many present small type 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 can even substitute LTE Cat 1 in lots of use instances.

Conclusion

Each LTE Cat 1bis and LTE-M are appropriate expertise selections for LPWA purposes. So earlier than making a alternative, one should contemplate expertise traits and regional deployment. One could also be a greater candidate than the opposite, or possibly each might be thought-about. u-blox can help with this sort of choice, relying on particular use instances and MNOs.

u-blox gives 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 collection, SARA-R4, which additionally gives 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 collection. Each collection have been additional miniaturized into the LEXI-R4 and LEXI-R5 type elements.

For LTE Cat 1bis, u-blox gives the LENA-R8 and LEXI-R10 collection. LENA-R8 can also be accessible 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 variety and is greatest fitted to high-performance purposes.