The Internet of Things (IoT) relies on various communication technologies for seamless connectivity between devices. These technologies can be categorized into short-range, medium-range, and long-range communication methods.

1. Short-Range Communication Technologies

These technologies are ideal for local device-to-device communication and are energy-efficient.

(a) NFC (Near Field Communication)

• Range: <10 cm
• Frequency: 13.56 MHz
• Speed: Up to 424 Kbps
• Use Cases: Contactless payments, access control, smart cards

(b) RFID (Radio Frequency Identification)

• Range: Up to 100 m (depends on frequency)
• Frequency: LF (125 kHz), HF (13.56 MHz), UHF (860-960 MHz)
• Use Cases: Inventory tracking, logistics, asset management

(c) Bluetooth & BLE (Bluetooth Low Energy)

• Range: 10-100 meters
• Frequency: 2.4 GHz
• Speed: 1-3 Mbps
• Use Cases: Wearables, health monitoring, smart home automation

(d) ZigBee

• Range: 10-100 meters
• Frequency: 2.4 GHz
• Speed: 250 Kbps
• Use Cases: Smart lighting, security systems, industrial automation

2. Medium-Range Communication Technologies

These technologies support moderate data transfer rates and are used in local networks.

(a) Wi-Fi

• Range: 50-100 meters
• Frequency: 2.4 GHz / 5 GHz
• Speed: 0.1-1 Gbps
• Use Cases: Smart homes, video streaming, industrial IoT

(b) 6LoWPAN (IPv6 over Low Power Wireless Personal Area Network)

• Range: 25-50 meters
• Frequency: Sub-GHz
• Speed: 0-250 Kbps
• Use Cases: Smart cities, industrial automation, environmental monitoring

3. Long-Range Communication Technologies

These technologies enable wide-area connectivity for IoT devices.

(a) LPWAN (Low Power Wide Area Network) Technologies

LoRaWAN (Long Range Wide Area Network)

• Range: Up to 10 km
• Frequency: Sub-GHz (868 MHz, 915 MHz)
• Speed: 40-250 Kbps
• Use Cases: Smart agriculture, remote monitoring, environmental sensors

NB-IoT (Narrowband IoT)

• Range: 1-15 km
• Frequency: Cellular bands
• Speed: 200-250 Kbps
• Use Cases: Smart meters, industrial IoT, asset tracking

(b) Cellular IoT (3G, 4G, 5G)

3G/4G LTE

• Range: Several kilometers
• Speed: 1-100 Mbps
• Use Cases: Connected cars, video surveillance, industrial automation

5G

• Range: 500 meters to several km
• Speed: 1-10 Gbps
• Use Cases: Autonomous vehicles, smart healthcare, real-time IoT applications