IoT Wireless Protocols

A panoramic view of wireless protocols for low power, low data rate, wide-area coverage, or local area networking

Protocol Comparison Overview

Zigbee

Features

Based on IEEE 802.15.4
Mesh Topology: Each node can relay → Large coverage area
Self-healing: If a node fails → Automatically finds a new path
Low Power: End devices can sleep (battery lasts for years)

Disadvantages:
  - 2.4G band is crowded
  - Does not natively support IP → Requires a gateway for conversion
  - Vendor lock-in (although Zigbee 3.0 improves this)

Typical Network

Coordinator ×1: Creates the network, acts as the gateway
Router ×N: Relays messages, must be constantly powered
End Device ×N: Sleepy devices, battery-powered

Common Applications: Philips Hue, Aqara, IKEA TRÅDFRI

Thread + Matter

Thread

Shares roots with Zigbee (802.15.4), but natively supports IPv6
Mesh topology, uses 6LoWPAN to compress IPv6 packets

Advantages:
  ✓ Every device has an IPv6 address → No application-layer gateway needed
  ✓ Truly decentralized (no single point of failure like a Coordinator)
  ✓ Border Router only acts as an IP bridge, does not perform protocol conversion

Issue: Still requires a Thread Border Router
       (Built into Apple TV, HomePod, Google Nest Hub, etc.)

Matter

Matter ≠ Wireless Protocol! Matter is a unified application-layer standard

Matter runs on top of these protocols:
  - Thread (Low-power Mesh)
  - WiFi (High bandwidth)
  - Ethernet (Wired)

Problems Matter Solves:
  "You have to use an Aqara Hub for Aqara devices, and a Hue Bridge for Hue..."
  Matter → One device can be controlled by Apple Home / Google Home / Alexa simultaneously

Note: Matter devices ≠ No Hub needed
      Thread devices still require a Thread Border Router
      (But they can be shared, not limited to a single brand)

LoRa / LoRaWAN

Why LoRa

WiFi/BLE/Zigbee coverage is too small (tens of meters)
Cellular modules are expensive + SIM card management is troublesome + High power consumption

LoRa: Exchanges very low data rates for extremely long distances
LoRa = Physical Layer (Semtech proprietary modulation)
LoRaWAN = MAC + Network Layer (Open Standard)

Key Features

Sub-GHz bands (433/868/915 MHz): Good wall penetration, less interference
Spread Spectrum Modulation (CSS): Can receive below noise floor (-140dBm sensitivity!)
Data Rate: 0.3 kbps ~ 50 kbps (Higher spreading factor = slower but longer range)

Link Budget: Max ~170dB
  → Urban areas 2~5km, Rural areas 10~15km

Power Consumption: Transmit ~100mA, Sleep ~1μA

LoRaWAN Network Architecture

The same uplink packet may be received by multiple Gateways simultaneously → Deduplicated by the Network Server

Agriculture: Soil moisture sensors (One every few kilometers, battery lasts years)
Meter Reading: Water/Electricity meters (Sub-GHz penetrates basements)
Tracking: Livestock/Assets GPS+LoRa
Environmental Monitoring: Weather stations/Water quality

Ultra-short range (<10cm), based on inductive coupling

Three Modes:
  Reader/Writer: Read/write tags (Access cards/Payments)
  Card Emulation: Phone emulates a card (Apple Pay/Transit cards)
  P2P: Small data exchange between devices (Android Beam, now marginalized)

NFC Tag Types:
  Type 1/2 (NTAG): Most common, small capacity (<2KB)
  Type 4 (DESFire): High security, access/payment
  Type 5 (ISO 15693): Slightly further range (~1m), libraries

Passive Tags: Derive energy from the reader's magnetic field → No battery needed

LF (125kHz):  Animal implants/Access control, extremely short range
HF (13.56MHz): NFC belongs to this category, libraries/ID cards
UHF (860~960MHz): Logistics/Warehouses, up to 10m+

LF/HF: Magnetic field coupling (Near field)
UHF: Electromagnetic wave backscatter (Far field)

Ultra-short pulses (ns level) + Large bandwidth (>500MHz)
→ Time of Flight (ToF) accurate to centimeter level

Features:
  - Indoor centimeter-level positioning (Much more accurate than WiFi/BLE)
  - Anti-multipath interference
  - Medium power consumption

Applications:
  - Apple AirTag / U1 Chip
  - Car Keys (CCC Digital Key)
  - Indoor Navigation
  - Sports Tracking (e.g., Football)

Frequency: 3.1~10.6 GHz (China: 6~9 GHz)

Battery Powered + Long Range (km level) → LoRa
Battery Powered + Smart Home Mesh → Thread/Zigbee
Need Direct IP Communication → Thread (IPv6)
Multi-brand Interoperability → Matter Devices
Payment/Access Control/Short Range → NFC
Centimeter-level Indoor Positioning → UWB
High Bandwidth + Low Latency + Power Insensitive → WiFi
Wearables + Phone Communication → BLE
Meter Reading + Cellular Coverage Available → NB-IoT (No need to build own gateways)