1116  Sigfox Technology Overview

1116.1 Introduction

⏱️ ~10 min | ⭐⭐ Intermediate | 📋 P09.C11.U01

Sigfox is both a proprietary LPWAN technology and the name of the French company that developed and operates it. Unlike other LPWAN technologies where you can deploy your own network, Sigfox operates as a network operator providing connectivity services globally. Sigfox pioneered the concept of ultra-narrow band (UNB) modulation for IoT, enabling billions of low-power devices to communicate with minimal infrastructure and energy consumption.

NoteLearning Objectives

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

  • Understand Sigfox’s ultra-narrow band (UNB) technology
  • Explain the Sigfox network architecture and business model
  • Compare Sigfox’s UNB modulation with other wireless technologies
  • Understand the key advantages and limitations of the operator model

1116.2 Prerequisites

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

  • LPWAN Fundamentals: Understanding the LPWAN technology class, design trade-offs, and positioning relative to other wireless technologies provides essential context for Sigfox’s ultra-narrow band approach
  • Networking Basics: Familiarity with network topologies (especially star topology), frequency bands, and wireless modulation concepts helps you grasp Sigfox’s network architecture
  • LoRaWAN Fundamentals: Comparing Sigfox with LoRaWAN’s spread spectrum approach highlights the unique characteristics and trade-offs of ultra-narrow band modulation

Imagine you need to send very simple messages—“the door opened,” “temperature is 22°C,” “water level is low”—from thousands of sensors spread across a city. You don’t need to send photos or videos, just tiny bits of information. You want these sensors to run on batteries for 10+ years without replacement. And you want them to work everywhere without setting up your own antennas.

Sigfox solves this exact problem. It’s both a technology and a company that operates a global wireless network specifically for the Internet of Things. Think of it like a cellular network (like Verizon or AT&T), but instead of smartphones sending emails and videos, it’s designed for IoT devices sending tiny messages.

What makes Sigfox special?

Sigfox uses ultra-narrow band (UNB) radio technology—imagine squeezing your radio signal into an extremely thin channel, like a laser beam instead of a flashlight. This narrow signal can travel very long distances (up to 50 km in rural areas!) and uses incredibly little power. Your sensor might send only 140 messages per day, each containing up to 12 bytes of data (about 12 characters).

The trade-off is simplicity: Sigfox is perfect for “send temperature once per hour” but terrible for “stream live video.” It’s like choosing between sending postcards (Sigfox) vs video calls (Wi-Fi)—different tools for different jobs.

Term Simple Explanation
Ultra-Narrow Band (UNB) Radio signal squeezed into a very thin frequency channel for long range
LPWAN Low-Power Wide-Area Network—sends data long distances on little power
Base Station Sigfox antenna tower that receives messages from nearby devices
Payload The actual data you send (max 12 bytes per message for Sigfox)
Message Limit Sigfox allows 140 uplink messages per day per device
Global Coverage Single subscription works across countries where Sigfox operates
ISM Band Unlicensed radio frequencies (868 MHz Europe, 902 MHz USA) anyone can use

1116.3 Sigfox Technology Overview

1116.3.1 The Company and Vision

Sigfox is a French company founded in 2009 with a vision to connect billions of IoT devices using a dedicated low-power wide-area network. Rather than selling equipment for customers to build their own networks, Sigfox operates as a network service provider—similar to how cellular carriers operate.

Key philosophy:

Table 1116.1: Sigfox technology characteristics and capabilities {#tbl-sigfox-summary}

1116.4 Sigfox Technology Summary

Property Details
Name Sigfox
Standard protocol is based on Ultra Narrow Band (UNB) ISM radio band
Designed for Uses Ultra Narrow Band (UNB) to transmit information between low power devices operating at 868 MHz frequency band, that divides the spectrum into 400 of 100 Hz channels
Connection range 30-50 km for rural areas, and 3-10 km for urban areas
Data rate 100bps, with a limit of 140 messages per day for each end device
  • Software-based solution: Network and computing complexity managed in the cloud
  • Simple devices: All intelligence in the network, not the endpoints
  • Global coverage: Single subscription works across countries
  • Ultra-low cost: Minimal device complexity reduces hardware costs

1116.4.1 Sigfox Network Architecture

The Sigfox network follows a star topology with operator-managed infrastructure handling all complexity:

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graph TB
    subgraph "End Devices"
        D1["Sensor 1<br/>(Temp/Humidity)"]
        D2["Sensor 2<br/>(Asset Tracker)"]
        D3["Sensor 3<br/>(Water Meter)"]
        D4["Sensor 4<br/>(Parking)"]
    end

    subgraph "Sigfox Network (Operator-Managed)"
        BS1["Base Station 1"]
        BS2["Base Station 2"]
        BS3["Base Station 3"]

        CLOUD["Sigfox Cloud<br/>Backend"]
    end

    subgraph "Customer Systems"
        APP["Customer<br/>Application"]
        DASH["Dashboard"]
    end

    D1 -.->|UNB 100Hz| BS1
    D1 -.->|Spatial diversity| BS2
    D2 -.->|UNB 100Hz| BS2
    D2 -.->|Spatial diversity| BS3
    D3 -.->|UNB 100Hz| BS1
    D3 -.->|Spatial diversity| BS3
    D4 -.->|UNB 100Hz| BS2

    BS1 -->|Internet| CLOUD
    BS2 -->|Internet| CLOUD
    BS3 -->|Internet| CLOUD

    CLOUD -->|HTTPS API<br/>Callbacks| APP
    CLOUD -->|HTTPS API| DASH

    style D1 fill:#2C3E50,color:#fff
    style D2 fill:#2C3E50,color:#fff
    style D3 fill:#2C3E50,color:#fff
    style D4 fill:#2C3E50,color:#fff
    style BS1 fill:#16A085,color:#fff
    style BS2 fill:#16A085,color:#fff
    style BS3 fill:#16A085,color:#fff
    style CLOUD fill:#E67E22,color:#fff
    style APP fill:#3498DB,color:#fff
    style DASH fill:#3498DB,color:#fff

Figure 1116.1: Sigfox star topology with base stations and cloud backend

{fig-alt=“Sigfox network architecture diagram showing a three-tier star topology with four end devices (temperature/humidity sensor, asset tracker, water meter, parking sensor) transmitting via ultra-narrow band modulation at 100 Hz to three base stations. Spatial diversity shown with multiple base stations receiving signals from each device. Base stations connect via internet to centralized Sigfox Cloud Backend. Customer systems (application server and dashboard) receive data via HTTPS API callbacks. Navy nodes represent end devices, teal nodes represent base stations, orange node represents cloud backend, blue nodes represent customer systems.”}

Key architectural features:

  • Star topology: Devices communicate directly with base stations (no mesh routing)
  • Operator-owned infrastructure: All base stations and backend managed by Sigfox Network Operator
  • Redundant reception: Multiple base stations receive each message for reliability
  • Cloud processing: Geolocation computed from signal strength across base stations
  • Simple devices: No network stack complexity, minimal power consumption
  • Asymmetric communication: Heavy uplink (140 msg/day), limited downlink (4 msg/day)

1116.4.2 Ultra-Narrow Band Modulation

Sigfox uses Ultra Narrow Band (UNB) modulation, which is fundamentally different from spread spectrum techniques used by LoRa or frequency hopping used by Bluetooth.

UNB Characteristics:

  • Extremely narrow channel bandwidth: 100 Hz per channel
  • Multiple channels across the ISM band
  • Low data rate: 100 bps uplink, 600 bps downlink
  • High receiver sensitivity: -126 to -142 dBm
  • Robust against interference and jamming

Comparison with other modulation schemes:

Technology Bandwidth Data Rate Sensitivity
Sigfox (UNB) 100 Hz 100 bps -142 dBm
LoRa (CSS) 125-500 kHz 250-5,470 bps -148 dBm
FSK (Cellular) 200 kHz 1-100 kbps -110 dBm
Wi-Fi (OFDM) 20-40 MHz 1-600 Mbps -90 dBm

1116.4.3 Sigfox vs LoRaWAN Protocol Stack Comparison

Understanding the architectural differences between Sigfox and LoRaWAN helps inform technology selection:

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graph LR
    subgraph "Sigfox Model"
        S_DEV["Device: $5-15"]
        S_BS["Base Stations<br/>(Operator-owned)"]
        S_BACKEND["Sigfox Cloud<br/>(Global)"]
        S_SUB["$6-10/year/device"]
    end

    subgraph "LoRaWAN Model"
        L_DEV["Device: $10-25"]
        L_GW["Gateways<br/>(User-deployed)<br/>$200-1,000 each"]
        L_NS["Network Server<br/>(TTN or private)"]
        L_COST["No per-device fee<br/>(Infrastructure CapEx)"]
    end

    S_DEV --> S_BS
    S_BS --> S_BACKEND
    S_BACKEND --> S_SUB

    L_DEV --> L_GW
    L_GW --> L_NS
    L_NS --> L_COST

    DIFF["Key Differences:<br/>Sigfox: Operator-dependent<br/>LoRaWAN: Self-deployable<br/>Sigfox: Subscription model<br/>LoRaWAN: Infrastructure investment"]

    S_SUB --> DIFF
    L_COST --> DIFF

    style S_DEV fill:#F39C12,color:#fff
    style S_BS fill:#E67E22,color:#fff
    style S_BACKEND fill:#E67E22,color:#fff
    style L_DEV fill:#16A085,color:#fff
    style L_GW fill:#27AE60,color:#fff
    style L_NS fill:#27AE60,color:#fff
    style DIFF fill:#2C3E50,color:#fff

Figure 1116.2: Sigfox vs LoRaWAN business model and cost comparison

Technology trade-offs:

Feature Sigfox LoRaWAN
Deployment complexity Very simple (Operator handles all) Moderate (Deploy gateways)
Infrastructure control None (Operator only) Full (Private networks)
Device cost $5-15 (Lowest) $10-25 (Low)
Operational cost $6-10/year subscription Gateway CapEx + power
Data rate 100 bps (Very low) 250-5,470 bps (Low-Medium)
Payload size 12 bytes (Tiny) 243 bytes (Small)
Message frequency 140/day limit No daily limit
Bidirectional Limited (4 downlink/day) Full (after each uplink)
Coverage dependency Operator network Self-deployed
Best for Simple sensors, metering Flexible IoT, moderate data

1116.5 Videos

NoteLPWAN Overview (Context for Sigfox)
LPWAN Overview (Context for Sigfox)
Lesson 4 - LPWAN positioning and trade-offs (provides context for Sigfox's operator model and UNB design).
TipCross-Hub Connections

Expand Your Learning:

  • Knowledge Map: Visualize how Sigfox fits within the broader LPWAN ecosystem and its relationship to cellular IoT, LoRaWAN, and application protocols
  • Quizzes Hub: Test your understanding with LPWAN technology comparison quizzes and Sigfox deployment scenario questions
  • Videos Hub: Watch curated videos on LPWAN positioning, operator network models, and UNB vs spread spectrum modulation techniques

1116.6 Summary

In this chapter, you learned about Sigfox’s core technology:

  • Company and Vision: Sigfox operates as a network-as-a-service provider, handling all infrastructure while customers focus on devices
  • Network Architecture: Star topology with operator-managed base stations and cloud backend
  • Ultra-Narrow Band: 100 Hz channel bandwidth enables exceptional range and interference immunity
  • Cost Model: Low device cost ($5-15) with annual subscription ($6-10/year) versus LoRaWAN’s infrastructure investment

Key specifications to remember:

  • Uplink: 100 bps, 12 bytes max, 140 messages/day
  • Downlink: 600 bps, 8 bytes max, 4 messages/day
  • Range: 3-10 km urban, 30-50 km rural
  • Receiver sensitivity: -142 dBm

1116.7 What’s Next

Now that you understand Sigfox’s technology foundations, continue to: