1152  NB-IoT vs LTE-M: Technology Comparison

1152.1 Learning Objectives

By the end of this chapter, you should be able to:

  • Compare NB-IoT and LTE-M technical specifications in detail
  • Understand the trade-offs between each technology
  • Select the appropriate technology for specific IoT applications
  • Evaluate dual-mode modules for flexible deployments
  • Understand Coverage Enhancement modes for each technology

1152.2 Prerequisites

Before diving into this chapter, you should be familiar with:

1152.3 NB-IoT vs LTE-M: The Core Differences

NoteKey Takeaway

In one sentence: NB-IoT optimizes for stationary devices needing extreme battery life and deep coverage; LTE-M enables mobile applications with real-time response and voice support.

Remember this: NB-IoT = static sensors (meters, parking); LTE-M = moving things (trackers, wearables).

⏱️ ~15 min | ⭐⭐ Intermediate | 📋 P09.C18.U02

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flowchart TD
    subgraph NBIOT["NB-IoT (Narrowband IoT)"]
        NB1["180 kHz Bandwidth<br/>(Single LTE PRB)"]
        NB2["250 kbps Max Rate"]
        NB3["No Handover Support<br/>(Stationary Only)"]
        NB4["164 dB MCL<br/>(Deep Coverage)"]
        NB5["10+ Year Battery<br/>with PSM"]
    end

    subgraph LTEM["LTE-M (Cat-M1)"]
        LM1["1.4 MHz Bandwidth<br/>(6 LTE PRBs)"]
        LM2["1 Mbps Max Rate"]
        LM3["Full Mobility<br/>(Handover up to 160 km/h)"]
        LM4["156 dB MCL"]
        LM5["VoLTE Voice Support"]
    end

    DECISION{"Select Technology"}

    DECISION -->|"Static sensors<br/>Deep coverage<br/>Ultra-low power"| NBIOT
    DECISION -->|"Mobile tracking<br/>Voice/VoLTE<br/>Real-time response"| LTEM

    style NB1 fill:#E67E22,stroke:#2C3E50,color:#fff
    style NB2 fill:#E67E22,stroke:#2C3E50,color:#fff
    style NB3 fill:#E67E22,stroke:#2C3E50,color:#fff
    style NB4 fill:#E67E22,stroke:#2C3E50,color:#fff
    style NB5 fill:#E67E22,stroke:#2C3E50,color:#fff
    style LM1 fill:#16A085,stroke:#2C3E50,color:#fff
    style LM2 fill:#16A085,stroke:#2C3E50,color:#fff
    style LM3 fill:#16A085,stroke:#2C3E50,color:#fff
    style LM4 fill:#16A085,stroke:#2C3E50,color:#fff
    style LM5 fill:#16A085,stroke:#2C3E50,color:#fff
    style DECISION fill:#2C3E50,stroke:#16A085,color:#fff

Figure 1152.1: NB-IoT vs LTE-M Technology Comparison and Selection Guide

{fig-alt=“Flowchart comparing NB-IoT (orange) and LTE-M (teal) cellular IoT technologies. NB-IoT features: 180 kHz bandwidth using single LTE PRB, 250 kbps maximum data rate, no handover support (stationary devices only), 164 dB Maximum Coupling Loss for deep indoor coverage, and 10+ year battery life with PSM power saving mode. LTE-M features: 1.4 MHz bandwidth using 6 LTE PRBs, 1 Mbps maximum data rate, full mobility support with handover up to 160 km/h, 156 dB MCL, and VoLTE voice calling support. Decision node (navy) shows selection criteria: choose NB-IoT for static sensors needing deep coverage and ultra-low power; choose LTE-M for mobile tracking, voice applications, and real-time response requirements.”}

1152.3.1 Detailed Technical Comparison

Feature NB-IoT (Cat-NB1) LTE-M (Cat-M1)
3GPP Release Release 13 (2016) Release 13 (2016)
Bandwidth 180 kHz (1 PRB) 1.4 MHz (6 PRBs)
Peak Data Rate DL 250 kbps 1 Mbps
Peak Data Rate UL 250 kbps 1 Mbps
Latency 1.6 - 10 seconds 10 - 15 ms
Mobility No (stationary) Yes (up to 160 km/h)
Handover Not supported Fully supported
Voice (VoLTE) No Yes
MCL (Coverage) 164 dB 156 dB
Power (Tx @ 23 dBm) 200 mA 350 mA
PSM Sleep Current 3-5 µA 5-10 µA
Battery Life 10+ years 5-10 years
Duplex Mode Half-duplex Half/Full-duplex
Module Cost (2024) $5-12 $8-18
Typical Data Plan $1-5/month $3-10/month
ImportantCritical Selection Criteria

Choose NB-IoT when: - Devices are stationary (meters, parking sensors, environmental monitors) - 10+ year battery life is required - Deep indoor coverage needed (basements, concrete structures) - Low data volume (<100 KB/month) - Cost-sensitivity is paramount ($5-12 module cost)

Choose LTE-M when: - Devices move (vehicles, wearables, pets) - Voice capability needed (emergency buttons, intercoms) - Real-time response required (<100 ms latency) - Higher data throughput needed (>250 kbps) - Full duplex communication required

1152.4 Deployment Modes

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flowchart LR
    subgraph "NB-IoT Deployment Modes"
        IN["In-Band<br/>Uses existing LTE PRB<br/>(1 PRB of 50 PRBs)"]
        GB["Guard Band<br/>Uses LTE guard band<br/>(unused spectrum)"]
        SA["Standalone<br/>Refarmed 2G spectrum<br/>(200 kHz GSM channel)"]
    end

    subgraph "LTE-M Deployment"
        LM["In-Band Only<br/>Uses 6 contiguous PRBs<br/>within LTE carrier"]
    end

    TOWER["Cell Tower<br/>(eNodeB)"]

    TOWER --> IN
    TOWER --> GB
    TOWER --> SA
    TOWER --> LM

    style IN fill:#E67E22,stroke:#2C3E50,color:#fff
    style GB fill:#E67E22,stroke:#2C3E50,color:#fff
    style SA fill:#E67E22,stroke:#2C3E50,color:#fff
    style LM fill:#16A085,stroke:#2C3E50,color:#fff
    style TOWER fill:#2C3E50,stroke:#16A085,color:#fff

Figure 1152.2: NB-IoT and LTE-M Deployment Mode Comparison

{fig-alt=“Diagram showing NB-IoT deployment modes (orange) versus LTE-M deployment (teal). NB-IoT supports three modes from cell tower: In-Band using 1 existing LTE PRB out of 50, Guard Band using unused spectrum between LTE carriers, and Standalone using refarmed 2G GSM 200 kHz channel. LTE-M supports only In-Band deployment using 6 contiguous PRBs within LTE carrier. This flexibility allows NB-IoT deployment even without LTE infrastructure using standalone mode.”}

1152.4.1 NB-IoT Deployment Flexibility

In-Band Mode: - Uses one 180 kHz Physical Resource Block (PRB) within existing LTE carrier - Shares spectrum with LTE, managed by scheduler - Most efficient use of existing infrastructure

Guard Band Mode: - Uses unused spectrum in LTE guard bands - Does not impact LTE capacity - Limited availability depending on LTE configuration

Standalone Mode: - Operates independently in refarmed 2G (GSM) spectrum - Uses 200 kHz channel (single GSM carrier) - Enables NB-IoT in areas without LTE coverage - Critical for rural deployments where 2G is available but LTE is not

1152.5 Coverage Enhancement Comparison

Both technologies provide coverage enhancement (CE) modes for challenging RF environments:

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graph TB
    subgraph "NB-IoT Coverage Enhancement Levels"
        CE0["CE Level 0<br/>Normal Coverage<br/>RSRP > -105 dBm<br/>1-4 Repetitions"]
        CE1["CE Level 1<br/>Extended Coverage<br/>-105 to -115 dBm<br/>8-16 Repetitions"]
        CE2["CE Level 2<br/>Extreme Coverage<br/>RSRP < -115 dBm<br/>64-128 Repetitions"]
    end

    subgraph "LTE-M Coverage Enhancement Modes"
        CEA["CE Mode A<br/>Normal Coverage<br/>RSRP > -105 dBm<br/>1-4 Repetitions"]
        CEB["CE Mode B<br/>Extended Coverage<br/>RSRP < -115 dBm<br/>Up to 32 Repetitions"]
    end

    MCL_NB["NB-IoT MCL: 164 dB<br/>+20 dB vs LTE"]
    MCL_LM["LTE-M MCL: 156 dB<br/>+12 dB vs LTE"]

    CE2 --> MCL_NB
    CEB --> MCL_LM

    style CE0 fill:#16A085,stroke:#2C3E50,color:#fff
    style CE1 fill:#E67E22,stroke:#2C3E50,color:#fff
    style CE2 fill:#c0392b,stroke:#2C3E50,color:#fff
    style CEA fill:#16A085,stroke:#2C3E50,color:#fff
    style CEB fill:#E67E22,stroke:#2C3E50,color:#fff
    style MCL_NB fill:#2C3E50,stroke:#16A085,color:#fff
    style MCL_LM fill:#2C3E50,stroke:#16A085,color:#fff

Figure 1152.3: Coverage Enhancement Comparison: NB-IoT CE Levels vs LTE-M CE Modes

{fig-alt=“Comparison of coverage enhancement capabilities between NB-IoT and LTE-M. NB-IoT provides three CE levels: CE0 (green) for normal coverage above -105 dBm with 1-4 repetitions, CE1 (orange) for extended coverage between -105 and -115 dBm with 8-16 repetitions, and CE2 (red) for extreme coverage below -115 dBm with 64-128 repetitions achieving 164 dB MCL (+20 dB versus standard LTE). LTE-M provides two modes: CE Mode A (green) for normal coverage with 1-4 repetitions, and CE Mode B (orange) for extended coverage with up to 32 repetitions achieving 156 dB MCL (+12 dB versus LTE). Shows NB-IoT advantage of 8 dB additional coverage for basement and underground deployments.”}

1152.5.1 Coverage Enhancement Trade-offs

Mode Repetitions Latency Impact Power Impact Use Case
NB-IoT CE0 1-4 Minimal Low Normal indoor
NB-IoT CE1 8-16 2-5x Moderate Deep indoor
NB-IoT CE2 64-128 10-50x High Basements, underground
LTE-M Mode A 1-4 Minimal Low Normal coverage
LTE-M Mode B Up to 32 2-10x Moderate Extended indoor
WarningTrade-off: Coverage vs Battery Life

NB-IoT CE2 (128 repetitions) impact: - Transmission time: 10-50x longer - Power consumption: 5-10x higher per transmission - Battery life reduction: 50-70% vs CE0

Real example: A water meter transmitting 4x/day: - CE0: 10-year battery life - CE2: 3-5 year battery life

Recommendation: Use CE2 only when absolutely necessary (underground vaults). Consider antenna upgrades or signal boosters as alternatives.

1152.6 Use Case Mapping

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quadrantChart
    title NB-IoT vs LTE-M Use Case Positioning
    x-axis Low Mobility --> High Mobility
    y-axis Low Data Rate --> High Data Rate

    quadrant-1 LTE-M Sweet Spot
    quadrant-2 Consider LTE Cat-1
    quadrant-3 NB-IoT Sweet Spot
    quadrant-4 Dual-Mode Preferred

    Smart Meters: [0.15, 0.2]
    Parking Sensors: [0.1, 0.15]
    Soil Sensors: [0.12, 0.18]
    Environmental: [0.2, 0.25]
    Asset Tags: [0.3, 0.2]
    Wearables: [0.6, 0.45]
    Pet Trackers: [0.65, 0.35]
    Fleet GPS: [0.8, 0.5]
    Security Cameras: [0.2, 0.9]
    Emergency Buttons: [0.4, 0.3]

Figure 1152.4: NB-IoT and LTE-M Use Case Quadrant Analysis

{fig-alt=“Quadrant chart showing IoT use case positioning between NB-IoT and LTE-M based on mobility (x-axis) and data rate (y-axis). NB-IoT sweet spot (lower-left quadrant) includes smart meters, parking sensors, soil sensors, environmental monitors, and static asset tags requiring low mobility and low data rate. LTE-M sweet spot (lower-right quadrant) includes wearables, pet trackers, fleet GPS requiring high mobility with moderate data rate. Upper quadrants show cases where dual-mode or LTE Cat-1 may be preferred for high data rates. Emergency buttons positioned in middle requiring moderate response time.”}

1152.6.1 Detailed Use Case Analysis

Application Technology Justification
Smart Water Meters NB-IoT Stationary, basement locations, 15-year life, 1 reading/hour
Smart Parking NB-IoT Ground-level, simple presence detection, cost-sensitive
Environmental Sensors NB-IoT Fixed location, low data, 10+ year battery
Agricultural Monitors NB-IoT Remote, solar/battery, infrequent updates
Fleet GPS Tracking LTE-M Highway speeds (120+ km/h), real-time location, handover critical
Wearables/Fitness LTE-M Body movement, health alerts, moderate data
Pet/Child Trackers LTE-M Mobility required, real-time alerts
Emergency Buttons LTE-M Low latency critical, VoLTE for confirmation
Industrial Monitoring Dual-Mode Coverage varies, some mobile equipment
Connected Cars LTE-M/5G High mobility, safety-critical latency
Figure 1152.5

1152.7 Dual-Mode Modules

For deployments spanning multiple use cases or uncertain requirements, dual-mode modules support both NB-IoT and LTE-M:

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flowchart TD
    MODULE["Dual-Mode Module<br/>(NB-IoT + LTE-M)"]

    CHECK{"Application<br/>Requirements"}

    NB["Switch to NB-IoT<br/>• Deep coverage needed<br/>• Stationary device<br/>• Ultra-low power mode"]

    LM["Switch to LTE-M<br/>• Device moving<br/>• Voice needed<br/>• Low latency required"]

    FALLBACK["Automatic Fallback<br/>• Primary unavailable<br/>• Coverage gaps<br/>• Carrier limitations"]

    MODULE --> CHECK
    CHECK -->|"Static + Deep Coverage"| NB
    CHECK -->|"Mobile + Real-time"| LM
    NB --> FALLBACK
    LM --> FALLBACK
    FALLBACK -->|"Coverage restored"| CHECK

    style MODULE fill:#2C3E50,stroke:#16A085,color:#fff
    style CHECK fill:#7F8C8D,stroke:#2C3E50,color:#fff
    style NB fill:#E67E22,stroke:#2C3E50,color:#fff
    style LM fill:#16A085,stroke:#2C3E50,color:#fff
    style FALLBACK fill:#9b59b6,stroke:#2C3E50,color:#fff

Figure 1152.6: Dual-Mode Module Operation with Automatic Technology Selection

{fig-alt=“Flowchart showing dual-mode cellular IoT module (navy) that supports both NB-IoT and LTE-M. Application requirements check (gray) determines technology: switches to NB-IoT (orange) when deep coverage is needed, device is stationary, or ultra-low power mode required; switches to LTE-M (teal) when device is moving, voice is needed, or low latency required. Automatic fallback (purple) handles cases when primary technology is unavailable due to coverage gaps or carrier limitations, cycling back to requirements check when coverage restores.”}

1152.7.1 Dual-Mode Module Examples

Module NB-IoT Bands LTE-M Bands Price (2024) Notes
Quectel BG96 B1, B3, B5, B8, B20, B28 B2, B4, B12, B13 $15-20 Most popular, GNSS included
u-blox SARA-R410M Multi-band Multi-band $18-25 Global variant available
Nordic nRF9160 Multi-band Multi-band $12-18 Integrated MCU + modem
Sequans Monarch 2 Multi-band Multi-band $10-15 Low-power optimized
TipWhen to Use Dual-Mode

Recommended for: - Global products shipped to multiple regions (carrier NB-IoT/LTE-M support varies) - Products with mixed static/mobile use cases - Future-proofing against carrier technology changes - Pilot deployments where requirements may evolve

Not recommended when: - Cost is primary driver (add $3-5 per module) - Single technology clearly matches all requirements - Simple, single-region deployment

1152.8 Knowledge Check

Question 1: A company deploys 10,000 smart water meters in basements throughout a city. Which technology should they choose?

  1. LTE-M - for faster data transmission
  2. NB-IoT - for deep coverage and long battery life
  3. 5G - for future-proofing
  4. Dual-mode - for flexibility

Answer: B) NB-IoT. Water meters are stationary (no mobility needed), located in basements (164 dB MCL provides +8 dB coverage vs LTE-M), need 10+ year battery life, and have low data requirements. NB-IoT’s lower module cost ($5-12 vs $8-18) also saves $30,000-60,000 across the deployment.

Question 2: Why can’t NB-IoT be used for vehicle tracking at highway speeds?

  1. Data rate is too low
  2. No handover support between cells
  3. Battery life is too short
  4. Voice is required

Answer: B) No handover support. NB-IoT was designed for stationary devices and does not support handover between cell towers. At highway speeds (100+ km/h), a device might cross cell boundaries every 2-3 minutes. Without handover, the connection would drop each time, requiring a full re-attach procedure (10-60 seconds). LTE-M supports seamless handover up to 160 km/h.

Question 3: A pet tracker needs to alert owners when a dog escapes the yard. Which is the most important selection criterion?

  1. Deep coverage (164 dB MCL)
  2. Low latency for real-time alerts
  3. VoLTE support
  4. 10-year battery life

Answer: B) Low latency. When a pet escapes, the owner needs immediate notification. LTE-M’s 10-15 ms latency enables near-instant alerts, while NB-IoT’s 1.6-10 second latency could mean the pet is already far away before the alert arrives. Additionally, pets move, requiring LTE-M’s mobility support.

1152.9 Summary

  • NB-IoT specializes in stationary, low-data-rate applications with 250 kbps data rate, 164 dB MCL for deep coverage, and 10+ year battery life
  • LTE-M provides mobility support with handover (up to 160 km/h), higher data rates (1 Mbps), lower latency (10-15 ms), and VoLTE for voice applications
  • Coverage enhancement modes extend reach: NB-IoT CE2 provides 128x repetitions for extreme coverage; LTE-M Mode B provides 32x
  • Dual-mode modules offer flexibility for uncertain requirements or global deployments at modest cost premium ($3-5)
  • Use case alignment is critical: static sensors use NB-IoT; mobile tracking uses LTE-M

1152.10 What’s Next

Continue your cellular IoT journey: