Everyone expected NB-IoT and LTE-M to dominate cellular IoT. The market had other plans. Here's what happened — and what it means for your next connected device.
In 2019, the industry consensus was clear: NB-IoT and LTE-M would account for over half of all cellular IoT connections by 2025. Analyst firms, carriers, and chipset vendors were aligned. The roadmap seemed set.
The reality in 2025 looks very different.
of all cellular IoT module shipments in 2025 are LTE Cat 1 bis — with 100% year-over-year shipment growth in 2024. (Sources: Counterpoint Research Q3 2025, Counterpoint 2024 Report)
LTE Cat 1 bis — a technology that was largely ignored when it was first standardized in 2016 — has quietly become the dominant force in cellular IoT. Meanwhile, NB-IoT and LTE-M, while still relevant in specific niches, have failed to deliver on their promise of universal global coverage.
As an IoT device development company with over 17 years of experience designing and manufacturing connected products, we’ve seen this shift firsthand. Here’s what every product manager, engineer, and business leader should know about Cat 1 bis.
What Is LTE Cat 1 bis?
LTE Cat 1 bis (also written as Cat 1bis, Cat-1 bis, or Cat1 bis) is an IoT-optimized variant of LTE Cat 1, standardized in 3GPP Release 13 (2016). The word “bis” comes from Latin meaning “second time around.”
The key difference: Cat 1 bis uses a single receive antenna instead of two, while maintaining the same data rates — 10 Mbps downlink, 5 Mbps uplink — and full LTE network compatibility.
This single-antenna design has profound implications for IoT device development. It means smaller PCBs, simpler RF design, lower bill of materials (BOM) cost, and more compact enclosures. For IoT devices where size and cost are critical constraints, this is a significant advantage.
But the real reason Cat 1 bis has exploded in adoption isn’t just the antenna. It’s everything else it brings to the table compared to the alternatives.
Cat 1 bis vs. NB-IoT vs. LTE-M: The Full Comparison
The three main cellular IoT technologies each have distinct strengths. Here’s how they compare across every dimension that matters for device development and deployment:
| Specification | LTE Cat 1 bis | LTE-M (Cat-M1) | NB-IoT (Cat-NB1) |
|---|---|---|---|
| 3GPP Release | Release 13 (2016) | Release 13 (2016) | Release 13 (2016) |
| Max download speed | 10 Mbps | 1 Mbps | 250 Kbps |
| Max upload speed | 5 Mbps | 1 Mbps | 200 Kbps |
| Latency | 10–15 ms | 15–30 ms | 1–10 seconds |
| Global network coverage | Any 4G LTE network | Operator-specific rollout | Operator-specific rollout |
| International roaming | Standard LTE roaming | Limited / improving | Very limited / bespoke |
| Voice (VoLTE) | Yes | Yes | No |
| Ideal for | Global, mobile, moderate-data IoT | Regional low-power + mobility | Static, ultra-low-data sensors |
Why Cat 1 bis Is Winning: 6 Key Advantages Over NB-IoT and LTE-M
The comparison table tells part of the story. But to understand why Cat 1 bis has overtaken the technologies that were supposed to dominate, you need to look at the practical realities of building and deploying IoT devices at scale.
1. Global Coverage Without Waiting for Operator Rollout
This is the single most important advantage of Cat 1 bis, and the one that has driven the fastest adoption.
NB-IoT and LTE-M require mobile operators to deploy specific network configurations. This rollout has been slow, uneven, and geographically fragmented.
Cat 1 bis runs on standard 4G LTE infrastructure. If there’s a 4G network — and there is in virtually every populated area on Earth — Cat 1 bis works. No special deployment. No waiting for operators. One hardware SKU, global deployment.
2. International Roaming That Actually Works
For IoT deployments that cross borders — fleet tracking, shipping containers, shared mobility, wearables — roaming is not optional. It’s fundamental.
Cat 1 bis inherits standard LTE roaming agreements — the same ones that have been working reliably for smartphones for years.
3. Surprising Power Efficiency
Cat 1 bis often delivers comparable or better energy efficiency in real-world conditions.
Time to transmit 500 bytes: Cat 1 bis completes in ~8 ms, while NB-IoT takes ~400 ms. Shorter active time = less energy per transmission. (Source: Cavli Wireless)
4. Lower Total Cost of Ownership
- Single antenna = simpler PCB layout, fewer components, smaller enclosure
- One global SKU = fewer certifications, simpler inventory
- Standard LTE data plans = less dependence on specialized IoT plans
- Faster FOTA updates = lower maintenance costs
5. A Clear Path to 5G
The 5G evolution path for Cat 1 bis is eRedCap (enhanced Reduced Capability), being standardized in 3GPP. LTE networks will remain operational well into the 2030s.
6. The 2G/3G Sunset Is Accelerating Migration
Over 135 mobile operators worldwide have completed or announced plans to retire 2G networks, and over 165 for 3G (GSA, December 2025). Cat 1 bis is the most natural replacement.
Best Use Cases for LTE Cat 1 bis
Asset Tracking & Logistics
Real-time GPS tracking across borders with seamless roaming.
Payment Terminals (POS)
Low-latency, reliable connectivity for point-of-sale devices.
Security & Alarm Systems
Always-on connectivity with VoLTE voice support.
Smart Metering & Utilities
Reliable data collection with firmware update capability.
Shared Mobility
E-scooters, e-bikes, car-sharing across multiple countries.
Wearables & Health Monitoring
Compact, low-power design for GPS watches and safety devices.
When Cat 1 bis Is NOT the Right Choice
- Ultra-deep indoor deployments: NB-IoT’s superior penetration may be better
- Extremely infrequent, tiny data payloads: Static sensors sending bytes once a day
- High-bandwidth applications: Video streaming requires Cat 4 or higher
How to Develop a Cat 1 bis IoT Device: A Practical Guide
Define Your Requirements
Map your application’s data rate, latency, mobility, power budget, and geographic needs.
Select the Right Cat 1 bis Module
Options from Quectel, Telit Cinterion, u-blox, Fibocom, and SIMCom.
Design the Hardware
PCB, antenna, and enclosure design. Antenna performance is critical.
Develop Firmware
AT commands, PSM/eDRX, FOTA, and SIM/eSIM management.
Certify for Target Markets
FCC, CE/RED, IC, and carrier certifications.
Industrialize and Scale
DFM optimization, sourcing, testing, and production.
Planning a Cellular IoT Device?
At Accent Systems, we handle the complete product development cycle for Cat 1 bis IoT devices: electronic design, firmware development, mechanical engineering, regulatory certification, and mass production — all from our facility in Barcelona.
Frequently Asked Questions About LTE Cat 1 bis
What is LTE Cat 1 bis?
LTE Cat 1 bis is an IoT-optimized variant of LTE Cat 1, introduced in 3GPP Release 13. It offers 10 Mbps down, 5 Mbps up using a single antenna instead of two. It works on any existing 4G LTE network.
What is the difference between Cat 1 bis and NB-IoT?
Cat 1 bis offers much higher data rates (10 Mbps vs. 250 Kbps), lower latency (milliseconds vs. seconds), full mobility, standard LTE roaming, and VoLTE voice. Cat 1 bis works on any 4G network; NB-IoT requires specific operator deployment.
What is the difference between Cat 1 bis and LTE-M?
Cat 1 bis provides 10x higher data rates (10 Mbps vs. 1 Mbps), lower latency, and works on any existing LTE network without operator-specific configuration. Both support voice, mobility, and power-saving modes.
Is LTE Cat 1 bis compatible with 5G?
Yes. Cat 1 bis devices can migrate to 5G core networks. The 5G evolution path is eRedCap. LTE networks are expected to remain operational well into the 2030s.
What are the best use cases for LTE Cat 1 bis?
Asset tracking, payment terminals, security systems, smart metering, shared mobility, wearables, IP cameras, and telematics. Ideal for applications requiring global connectivity and moderate data rates.
How does the 2G/3G sunset affect IoT devices?
According to GSA (December 2025), 136 operators in 68 markets have completed or planned 2G shutdowns, and 167 operators in 67 markets are progressing on 3G switch-offs. LTE Cat 1 bis is the most straightforward replacement with global LTE coverage and a future path to 5G.
The Bottom Line
The cellular IoT landscape has shifted. Cat 1 bis has emerged as the pragmatic winner — offering the best combination of global coverage, roaming reliability, data performance, and cost for the vast majority of IoT use cases.
For companies building connected products: LTE Cat 1 bis should be your default consideration for any new cellular IoT device.
