1142  NB-IoT vs LTE-M Technology Comparison

1142.1 Learning Objectives

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

  • Compare Technical Specifications: Evaluate bandwidth, data rate, coverage, and mobility differences
  • Select Appropriate Technology: Choose between NB-IoT and LTE-M based on application requirements
  • Analyze Use Cases: Match technology capabilities to specific IoT deployment scenarios
  • Calculate Trade-offs: Assess power, latency, and cost implications for each technology

1142.2 Prerequisites

Required Chapters:

Technical Background:

  • Understanding of cellular IoT categories
  • Basic RF concepts (bandwidth, coverage)
  • Power consumption fundamentals

Estimated Time: 25 minutes

1142.3 Technology Overview

NB-IoT (Cat-NB1) and LTE-M (Cat-M1) are both 3GPP cellular IoT technologies, but optimized for different use cases.

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graph TB
    subgraph "NB-IoT (Cat-NB1)"
        NB_BW["Bandwidth: 180 kHz"]
        NB_RATE["Data Rate: ~250 kbps"]
        NB_MCL["Coverage: 164 dB MCL<br/>(Deep indoor: B3-B4)"]
        NB_MOB["Mobility: Stationary only<br/>No handover"]
        NB_PWR["Battery: 10-20 years<br/>PSM: < 5 µA"]
        NB_VOICE["Voice: No"]
        NB_USE["Use: Meters, sensors<br/>Environmental monitoring"]
    end

    subgraph "LTE-M (Cat-M1)"
        LTM_BW["Bandwidth: 1.4 MHz"]
        LTM_RATE["Data Rate: ~1 Mbps"]
        LTM_MCL["Coverage: 156 dB MCL<br/>(Good indoor penetration)"]
        LTM_MOB["Mobility: Up to 160 km/h<br/>Full handover"]
        LTM_PWR["Battery: 5-10 years<br/>Higher power"]
        LTM_VOICE["Voice: Yes (VoLTE)"]
        LTM_USE["Use: Wearables, vehicles<br/>Asset tracking"]
    end

    DECISION["Choose Based On:"]

    NB_USE --> DECISION
    LTM_USE --> DECISION

    DECISION --> STATIC["Static sensors<br/>Deep coverage needed<br/>→ NB-IoT"]
    DECISION --> MOBILE["Mobile assets<br/>Higher data rates<br/>Voice needed<br/>→ LTE-M"]

    style NB_BW fill:#27AE60,color:#fff
    style NB_MCL fill:#27AE60,color:#fff
    style NB_PWR fill:#27AE60,color:#fff
    style NB_USE fill:#27AE60,color:#fff
    style LTM_BW fill:#3498DB,color:#fff
    style LTM_MOB fill:#3498DB,color:#fff
    style LTM_VOICE fill:#3498DB,color:#fff
    style LTM_USE fill:#3498DB,color:#fff
    style DECISION fill:#2C3E50,color:#fff

Figure 1142.1: NB-IoT vs LTE-M Technology Comparison and Selection Guide

1142.4 Detailed Specification Comparison

1142.4.1 Core Technical Differences

Feature NB-IoT (Cat-NB1) LTE-M (Cat-M1)
Bandwidth 180 kHz (1 PRB) 1.4 MHz (6 PRBs)
Data Rate (DL) 25-250 kbps 1 Mbps
Data Rate (UL) 20-250 kbps 1 Mbps
Coverage (MCL) 164 dB (+20 dB vs GPRS) 156 dB (+15 dB vs GPRS)
Mobility Stationary/Limited (idle reselection) Full handover (up to 160 km/h)
Battery Life 10-15 years (PSM: <5 µA) 5-10 years (PSM: <15 µA)
Voice Support No Yes (VoLTE)
Latency 1.6-10 seconds 10-15 ms
Module Cost $8-12 $15-20

1142.4.2 Application Mapping

Technology Best For Examples
NB-IoT Ultra-low power, stationary Smart metering, Environmental sensors, Static asset tracking
LTE-M Mobile, higher data rate Wearables, Connected vehicles, Voice-enabled devices

1142.5 Decision Framework

1142.5.1 Choose NB-IoT When:

  • Ultra-low power priority (10+ year battery life required)
  • Stationary devices (no mobility needed)
  • Deep indoor coverage (basements, underground)
  • Low cost per device ($8-12/module)
  • Simple, infrequent data (daily readings)

1142.5.2 Choose LTE-M When:

  • Mobility required (vehicles, wearables)
  • Higher data rates needed (firmware OTA, GPS tracking)
  • Voice capability needed (VoLTE)
  • Lower latency required (10-15ms)
  • Real-time applications
WarningCommon Misconception: “NB-IoT supports full mobility like LTE”

The Misconception: Many developers assume NB-IoT supports full cellular handover and high-speed mobility because it’s built on LTE infrastructure.

The Reality: NB-IoT is designed for stationary or low-mobility devices with only idle mode cell reselection, not connected mode handover.

Real-World Impact: A European logistics company deployed 5,000 NB-IoT trackers on shipping containers expecting seamless tracking during 100 km/h truck transport. Result: 72% connection failures during handover between cells, requiring complete device redesign with LTE-M modules ($850,000 additional cost, 6-month project delay).

The Technical Difference:

Feature NB-IoT LTE-M
Handover Type Idle mode reselection only Connected mode handover
Maximum Speed Stationary to walking (3-5 km/h) Up to 160 km/h
Reconnection Time 5-10 seconds (RRC connection re-establishment) Seamless (<100 ms handover)
Use Case Fixed sensors, smart meters Vehicle tracking, wearables

Cost of Getting It Wrong: Replacing NB-IoT modules with LTE-M costs $12 more per device (hardware) + $30 labor + downtime, totaling $42-50 per unit for retrofit deployments.

1142.6 Data Rate Analysis

NB-IoT (25-250 kbps) is like a slow but efficient delivery truck: - Perfect for small packages (sensor readings) - Takes longer for big deliveries (firmware updates) - Very fuel-efficient (low power)

LTE-M (1 Mbps) is like a fast courier van: - Quick delivery for any package size - Can handle larger items (video thumbnails, voice) - Uses more fuel (higher power)

Which to choose? - Sending a temperature reading (100 bytes)? Either works, NB-IoT saves power - Streaming GPS every second? LTE-M handles it easily - Voice call capability? Only LTE-M supports this

1142.6.1 Use Case: Smart Metering

Daily readings (typical operation): - Data size: 100 bytes per reading - Frequency: 1x per day - Data rate needed: 100 bytes / 86,400 seconds = 0.001 kbps average - NB-IoT rate: 25-160 kbps - More than sufficient

Firmware updates (occasional): - File size: 100 KB (typical MCU firmware) - Maximum acceptable download time: 1-2 hours - Minimum rate needed: 100 KB / 7200 sec = 14 bytes/sec = 0.11 kbps - NB-IoT rate: 25 kbps - Can transfer in ~32 seconds

Conclusion: NB-IoT is ideal for smart metering - sufficient bandwidth with superior power efficiency.

1142.7 Coverage Comparison

1142.7.1 Maximum Coupling Loss (MCL)

Technology MCL vs GPRS Best For
NB-IoT 164 dB +20 dB Deep basements, underground
LTE-M 156 dB +15 dB Indoor, urban canyons
GPRS 144 dB baseline Above ground

NB-IoT’s 8 dB advantage over LTE-M translates to: - 2.5x better link budget - Better penetration through concrete/steel - Longer range in rural areas

1142.8 Power Consumption Analysis

1142.8.1 Sleep Current Comparison

Mode NB-IoT LTE-M
PSM (Deep Sleep) < 5 µA < 15 µA
eDRX (Reachable Sleep) 15 µA 30 µA
Idle (Connected) 1-5 mA 1-5 mA
Active TX 200-400 mA 200-500 mA

1142.8.2 Battery Life Calculation

NB-IoT Smart Meter (Daily Reading): - Daily operation: 1.6 mAs per reading - Monthly firmware update: 3,200 mAs - Annual consumption: ~39,000 mAs = 10.8 mAh - Battery life (2500 mAh): 230 years theoretical (10-15 years practical)

LTE-M Asset Tracker (Hourly Update): - Hourly operation: 10 mAs per update - Annual consumption: ~87,600 mAs = 24 mAh - Battery life (2500 mAh): 100 years theoretical (5-10 years practical)

The practical limits come from battery self-discharge and component aging.

1142.9 Latency Considerations

Technology Typical Latency Acceptable For
NB-IoT 1.6-10 seconds Daily readings, periodic updates
LTE-M 10-15 ms Real-time tracking, voice, alerts

1142.9.1 When Latency Matters

NB-IoT Acceptable (seconds OK): - Smart meters (daily readings) - Environmental sensors (hourly data) - Parking sensors (state change reporting)

LTE-M Required (<100 ms): - Emergency alerts - Voice calls - Real-time asset tracking - Health monitoring devices

1142.10 Application Examples

1142.10.1 Scenario: Vaccine Cold Chain Tracking

A logistics company needs to track refrigerated containers: - Temperature reports every 5 minutes - GPS location every 15 minutes - Emergency alerts with <1 minute latency - Movement by truck/ship at varying speeds - 30-day battery life on 10 Ah battery

Analysis:

Requirement NB-IoT LTE-M Winner
Mobility (trucks 60-100 km/h) Limited Full handover LTE-M
Emergency latency (<1 min) 1.6-10 sec (marginal) 10-15 ms LTE-M
Battery (30 days) Excellent Good Both OK
Data rate (GPS+temp) Sufficient Excellent Both OK

Conclusion: LTE-M is required for this mobile, latency-sensitive application.

1142.10.2 Scenario: Underground Parking Sensor

A smart city deploys parking occupancy sensors: - Status change reporting only - Deep underground concrete structure - 10-year battery requirement - Stationary devices - Cost-sensitive deployment

Analysis:

Requirement NB-IoT LTE-M Winner
Coverage (164 dB MCL) 164 dB 156 dB NB-IoT
Battery (10 years) 10-15 years 5-10 years NB-IoT
Mobility Stationary Over-spec NB-IoT
Cost $8-12/module $15-20/module NB-IoT

Conclusion: NB-IoT is optimal for stationary, deep-coverage, low-power applications.

1142.11 Knowledge Check

Question 1: Compare NB-IoT’s data rates (25-160 kbps) with LoRaWAN (0.3-50 kbps) and LTE Cat-M1 (1 Mbps). For which IoT application is NB-IoT’s data rate MOST appropriate?

NB-IoT’s data rate is optimized for infrequent sensor data and occasional larger transfers, making it ideal for smart metering. Video (A) needs 2-4 Mbps (NB-IoT provides 250 kbps max). Voice (B) requires low latency that NB-IoT cannot provide. Industrial control (D) needs 1ms latency vs NB-IoT’s 1-10 seconds.

Question 2: A logistics company needs to track refrigerated containers transporting vaccines. Each container reports temperature every 5 minutes, GPS location every 15 minutes, and must support emergency alerts with <1 minute latency. Containers move by truck/ship at varying speeds. Which cellular IoT technology should you choose?

LTE-M is the only viable option for this mobile cold chain application:

Mobility Support: LTE-M provides full handover at speeds up to 160 km/h. NB-IoT only supports idle mode reselection (stationary devices).

Latency: LTE-M provides 10-15 ms typical latency, meeting the <1 minute emergency alert requirement. NB-IoT’s 1.6-10 seconds is marginal.

Why not alternatives: EC-GSM-IoT is being phased out with 2G sunset. Wi-Fi has no coverage over ocean.

Question 3: Rank these cellular IoT technologies by bandwidth capability from HIGHEST to LOWEST:

  • LTE-M (Cat-M1)
  • EC-GSM-IoT
  • NB-IoT (Cat-NB1)

Correct ranking by bandwidth (highest to lowest):

1. LTE-M (Cat-M1): 1 Mbps - 1.4 MHz bandwidth (6 PRBs), suitable for mobile IoT with voice support

2. NB-IoT (Cat-NB1): 250 kbps - 180 kHz bandwidth (1 PRB), optimized for static sensors

3. EC-GSM-IoT: 70-240 kbps - 200 kHz bandwidth (GSM carrier), being phased out

1142.12 Summary

  • Bandwidth difference: NB-IoT (180 kHz, 250 kbps) vs LTE-M (1.4 MHz, 1 Mbps) - LTE-M is 4x faster
  • Coverage advantage: NB-IoT’s 164 dB MCL beats LTE-M’s 156 dB by 8 dB (2.5x better penetration)
  • Mobility support: NB-IoT is stationary-only; LTE-M supports full handover at 160 km/h
  • Battery life: NB-IoT achieves 10-15 years; LTE-M achieves 5-10 years with similar batteries
  • Voice capability: Only LTE-M supports VoLTE for voice-enabled applications
  • Selection criteria: Choose NB-IoT for stationary/deep coverage; choose LTE-M for mobile/low-latency

1142.13 What’s Next

Test your comprehensive understanding of NB-IoT: