1127 NB-IoT Applications and Use Cases

Smart Metering, Asset Tracking, and Smart City Deployments

Prerequisites: NB-IoT Introduction | NB-IoT Architecture

This enables: NB-IoT Power Optimization | NB-IoT Practical Guide

1127.1 Learning Objectives

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

Design NB-IoT solutions: Select appropriate use cases for smart metering, asset tracking, and monitoring
Calculate power budgets: Estimate battery life using PSM and eDRX power-saving modes
Analyze link budgets: Determine coverage feasibility for different deployment scenarios
Evaluate deployment costs: Compare NB-IoT with alternative technologies for specific applications

1127.2 Application Examples

1127.2.1 Smart Metering

Use case: Smart Water Meters

Configuration:

Message frequency: 1 reading/day (meter value, diagnostics)
Payload size: 50-100 bytes (meter reading, status, alarms)
Power mode: PSM with T3412 = 24 hours
Battery life: 10-15 years with 3.6V, 5 Ah battery
Coverage: Deep basement penetration critical

Benefits over alternatives:

No gateway deployment needed (100,000s of meters)
Guaranteed delivery (utility billing critical)
Deep penetration (meters often in basements)
Mobility (some meters on mobile infrastructure)

1127.2.2 Asset Tracking

Use case: Container Tracking

Configuration:

Stationary: PSM, 1 update/day (battery conservation)
In-transit: eDRX, 1 update/4-6 hours (reachable for alerts)
Payload: GPS coordinates (8 bytes) + status (4 bytes) + sensor data
Battery: 3.6V, 10 Ah -> 3-5 years

NB-IoT advantages:

Global roaming (operator agreements)
Mobility support (handoff between cells)
Higher data rate for bulk uploads
Firmware updates over-the-air

1127.2.3 Smart City Applications

Use case: Smart Parking

Configuration:

Event-driven: Send on occupancy change (empty <-> occupied)
Heartbeat: Every 6 hours if no events (health check)
Power mode: PSM between events, eDRX if downlink commands needed
Payload: 10-20 bytes (status, battery, timestamp)
Battery life: 5-10 years (depends on turnover rate)

Why NB-IoT:

Existing cellular coverage (no gateway deployment in public spaces)
Reliable delivery (real-time parking availability)
Massive capacity (thousands of sensors per cell)
Carrier-grade security (public infrastructure)

1127.3 Worked Example: Battery Life Calculation for Smart Meter

Scenario: A utility company is deploying NB-IoT smart water meters in residential basements. Each meter needs to send a 50-byte reading once per day and operate for 10+ years on a single 6000 mAh battery.

Given:

Battery capacity: 6000 mAh (lithium thionyl chloride, 3.6V)
Payload size: 50 bytes per transmission
Transmission frequency: 1 message per day
NB-IoT module specifications:
- Sleep current (PSM): 3 uA
- Active TX current: 220 mA
- Active RX current: 40 mA
- TX duration: 1.5 seconds (including network attach)
- RX duration: 0.5 seconds (ACK)
Self-discharge rate: 1% per year

Step 1: Calculate daily active energy consumption

TX energy = 220 mA x 1.5 s = 330 mAs = 0.0917 mAh
RX energy = 40 mA x 0.5 s = 20 mAs = 0.0056 mAh
Active total per transmission = 0.0973 mAh

Step 2: Calculate daily sleep energy consumption

Sleep duration = 24 hours - 2 seconds = 23.9994 hours
Sleep energy = 3 uA x 23.9994 hours = 0.072 mAh

Step 3: Calculate total daily energy and theoretical battery life

Daily consumption = 0.0973 mAh + 0.072 mAh = 0.1693 mAh
Theoretical life = 6000 mAh / 0.1693 mAh/day = 35,440 days = 97 years

Step 4: Apply real-world derating factors

Battery self-discharge: 1%/year over 15 years = 15% loss
Temperature derating (basement, 10-20C): 5% capacity reduction
End-of-life threshold (3.0V cutoff): 10% unusable capacity
Effective capacity = 6000 x 0.85 x 0.95 x 0.90 = 4,373 mAh

Practical life = 4,373 mAh / 0.1693 mAh/day = 25,830 days = 70.7 years

Step 5: Account for coverage enhancement repetitions

Basement installation may require CE Mode B (up to 2048 repetitions)
Worst-case TX duration: 1.5s x 4 (repetitions) = 6 seconds
Revised TX energy = 220 mA x 6 s = 0.367 mAh
Revised daily = 0.367 + 0.0056 + 0.072 = 0.445 mAh
Practical life with CE = 4,373 / 0.445 = 9,826 days = 26.9 years

Result: Even with coverage enhancement for deep basement penetration, the meter achieves 26+ year theoretical battery life, well exceeding the 10-year requirement.

Key insight: PSM (Power Saving Mode) is the critical enabler - without it, sleep current of 15-50 mA would reduce battery life to weeks. The 3 uA PSM sleep current represents a 5000x reduction in idle power consumption.

1127.4 Worked Example: Link Budget for Underground Parking Sensor

Scenario: A smart city wants to deploy occupancy sensors in an underground parking garage (2 levels below ground). Will NB-IoT provide reliable coverage?

Given:

Base station EIRP: 43 dBm (20W)
Frequency: 850 MHz (Band 5)
Distance to base station: 1.5 km
Penetration losses: Ground level concrete (15 dB), each underground level (12 dB)
NB-IoT device sensitivity: -141 dBm (CE Mode B)
Required link margin: 10 dB

Step 1: Calculate free space path loss (FSPL)

FSPL = 20 log10(d) + 20 log10(f) + 32.45
FSPL = 20 log10(1.5 km) + 20 log10(850 MHz) + 32.45
FSPL = 3.52 + 58.59 + 32.45 = 94.56 dB

Step 2: Add building and underground penetration losses

Ground floor penetration: 15 dB
Underground Level 1: 12 dB
Underground Level 2: 12 dB
Total penetration loss = 15 + 12 + 12 = 39 dB

Step 3: Calculate total path loss

Total path loss = FSPL + penetration + shadow fading
Total path loss = 94.56 + 39 + 8 (urban shadow fading)
Total path loss = 141.56 dB

Step 4: Determine received signal strength

RSSI = EIRP - Path Loss + Antenna Gain
RSSI = 43 dBm - 141.56 dB + 0 dBi (sensor antenna)
RSSI = -98.56 dBm

Step 5: Compare to sensitivity and calculate margin

NB-IoT sensitivity (CE Mode B): -141 dBm
Link margin = Sensitivity - RSSI = -141 - (-98.56) = 42.44 dB
Required margin: 10 dB
Available margin: 42.44 dB > 10 dB (Sufficient)

Result: NB-IoT provides 42 dB of link margin for the underground parking sensor, well above the 10 dB requirement.

Key insight: NB-IoT’s 164 dB Maximum Coupling Loss (MCL) specification - achieved through repetition coding and narrow bandwidth - provides 20 dB more coverage than standard LTE.

1127.5 Worked Example: Coverage Enhancement Repetitions

Scenario: A building management system deploys environmental sensors inside elevator shafts and mechanical rooms. These locations have severe RF attenuation. How many NB-IoT repetitions are required?

Given:

Base station EIRP: 46 dBm (typical macro cell)
Frequency: 700 MHz (Band 28)
Distance to base station: 800 meters
Building penetration losses:
- Exterior wall: 15 dB
- Interior concrete walls (2): 10 dB each
- Elevator shaft steel: 25 dB
NB-IoT module sensitivity (no repetitions): -124 dBm
Target reliability: 99.9%
Required link margin: 8 dB

Step 1: Calculate path loss to elevator shaft

Free-space path loss (800m at 700 MHz):
FSPL = 20 x log10(0.8) + 20 x log10(700) + 32.45
FSPL = -1.94 + 56.9 + 32.45 = 87.4 dB

Building penetration:
- Exterior wall: 15 dB
- Interior walls (2x10): 20 dB
- Elevator shaft steel: 25 dB
- Total penetration: 60 dB

Total path loss = 87.4 + 60 = 147.4 dB

Step 2: Calculate repetitions needed

NB-IoT repetition gain:

Repetitions	Processing Gain	Effective Sensitivity
1 (none)	0 dB	-124 dBm
2	3 dB	-127 dBm
4	6 dB	-130 dBm
8	9 dB	-133 dBm
16	12 dB	-136 dBm
32	15 dB	-139 dBm
64	18 dB	-142 dBm
128	21 dB	-145 dBm
256	24 dB	-148 dBm

Step 3: Analyze worst-case scenario

Add worst-case factors:
- Body absorption (technician nearby): 3 dB
- Electrical interference: 5 dB
- Shadow fading (99.9% reliability): 10 dB
Total additional margin needed: 18 dB

For extreme environments, maximum 2048 repetitions -> +33 dB gain

Result: For extreme deep indoor deployments, NB-IoT Coverage Enhancement Mode B with maximum repetitions provides connectivity but at cost: 20-minute transmission time and reduced battery life.

Key Insight: NB-IoT’s 164 dB MCL is achieved through repetition coding, but each 3 dB of coverage extension doubles transmission time. For extreme environments (>150 dB path loss), consider in-building DAS or femtocell deployment.

1127.6 Real-World Case Study: Municipal Water Utility

The Challenge: A mid-sized city wants to modernize water metering to detect leaks, eliminate manual meter reading, and enable time-of-use billing.

The NB-IoT Solution:

Hardware per meter:

NB-IoT module: $8
Battery (AA lithium): $3
Installation: $15
Total per meter: $26

Data transmission pattern:

Daily consumption report: 200 bytes/day
Leak alert (if triggered): 150 bytes
Monthly billing data: 500 bytes
Average: 6.4 KB/month per meter

Annual operational costs (50,000 meters):

Cost Component	Per Meter	50,000 Meters
Cellular data plan	$2.00/year	$100,000
Network maintenance	$0.50/year	$25,000
Battery replacement (year 12)	$0.25/year amortized	$12,500
Total Annual	$2.75	$137,500

Comparison to manual reading:

Method	Annual Cost	Notes
Manual meter reading	$600,000	$1/read x 12 months x 50,000
NB-IoT automated	$137,500	Cellular + maintenance
Annual Savings	$462,500	77% reduction

Results after 3 years:

Leak detection: Identified 847 leaks, saving 42 million gallons/year
Billing accuracy: Reduced disputed bills by 94%
Operational savings: $1.4 million over 3 years
No cellular outages: 99.7% uptime (carrier SLA: 99.5%)
Zero battery failures (ongoing monitoring confirms 12+ year projection)

Key insight: The payback period was 4.2 months. After that, the city saves $462k annually compared to manual reading.

1127.7 Knowledge Check

Question: A smart city deploys 50,000 smart water meters across urban and suburban areas. The meters are installed in basements, underground utility vaults, and building interiors. They need to send 50-byte readings once daily and must operate for 10+ years on battery. Which LPWAN technology is MOST suitable?

Explanation: NB-IoT is optimal for this smart metering deployment:

Why NB-IoT wins:

Coverage: 164 dB MCL (vs LoRaWAN 157 dB) - critical for basements
Infrastructure: Zero gateway deployment (uses existing cell towers)
Reliability: Carrier SLA for billing-grade data
Scale: Handles 50,000+ devices without custom infrastructure

Why not others:

LoRaWAN: Would need ~500 gateways for city coverage, basement penetration gaps
Sigfox: 12-byte payload limit (50 bytes would need multiple messages)
LTE-M: Overkill for 50-byte daily readings, higher power consumption

Question: Technology Selection for Asset Tracking

You’re designing a nationwide asset tracking system for shipping containers that need to report location and temperature every 4 hours. Your containers travel across highways, rural areas, and inside cities. Battery replacement is expensive (containers are scattered globally), so you need 5-10 year battery life.

Which technology should you choose?

LoRaWAN (requires gateway infrastructure)
Wi-Fi (high power, short range)
NB-IoT (cellular IoT, licensed spectrum)
Bluetooth Low Energy (very short range)

Answer and Detailed Explanation

Correct Answer: C) NB-IoT

Why NB-IoT is the Best Choice:

1. Nationwide Coverage Without Gateway Deployment

NB-IoT uses existing cellular infrastructure
Containers automatically connect wherever there’s cellular coverage
No need to deploy your own gateways

2. Battery Life Calculation: 5-10 Years is Achievable

Container reporting cycle (every 4 hours):
1. Wake up from PSM (deep sleep)
2. Get GPS fix: ~30 seconds (100mA)
3. Read temperature sensor: 50ms (5mA)
4. Send NB-IoT uplink (100 bytes): ~2 seconds (200mA)
5. Enter PSM (deep sleep): 10uA

Daily consumption:
6 reports/day x 0.984 mAh = 5.9 mAh/day

Battery life with 20,000 mAh battery:
20,000 mAh / 5.9 mAh/day = 3,389 days = 9.3 years

3. Mobility and Roaming Support

NB-IoT supports mobility (handoff between cells)
Carrier roaming agreements enable global tracking
Containers can travel between countries seamlessly

Real-World Example: Maersk Smart Container Tracking

Fleet size: 4+ million containers globally
Reporting: Location, temperature, humidity, shock events
Battery life: 10-15 years with PSM
Coverage: Operates in 130+ countries with roaming agreements
ROI: Reduced cargo loss by 30% through real-time monitoring

1127.8 Summary

Smart metering is ideal for NB-IoT: daily readings, basement coverage, 10+ year battery life, no gateway infrastructure
Asset tracking benefits from NB-IoT’s mobility support and global roaming agreements
Smart city applications (parking, lighting) leverage existing cellular coverage and carrier-grade reliability
Battery life calculations must account for PSM sleep current, TX duration, CE repetitions, and battery derating
Link budget analysis confirms NB-IoT’s +20 dB coverage advantage for deep indoor deployments

1127.9 What’s Next

Continue your NB-IoT learning journey with these related topics:

NB-IoT Power Optimization - Master PSM and eDRX configuration for maximum battery life
NB-IoT Practical Guide - Learn from common mistakes and real-world deployment pitfalls
NB-IoT Lab Simulation - Hands-on ESP32 simulation of NB-IoT concepts