Wireless and Mobile Networking
Wireless networking enables communication without physical cables, using radio frequencies, infrared, or microwave signals. It provides mobility, ease of installation, and flexibility but faces challenges like interference, security, and lower bandwidth compared to wired networks.
IEEE 802.11 (Wi-Fi)
Wi-Fi (IEEE 802.11) is the dominant wireless LAN standard. Key versions include 802.11a (5 GHz, 54 Mbps), 802.11b (2.4 GHz, 11 Mbps), 802.11g (2.4 GHz, 54 Mbps), 802.11n (both bands, 600 Mbps), 802.11ac (5 GHz, multi-gigabit), and 802.11ax (Wi-Fi 6). Wi-Fi uses CSMA/CA for media access.
Bluetooth and PAN
Bluetooth (IEEE 802.15.1) connects devices within a short range (up to 100 m). It forms piconets (up to 8 devices) and scatternets. Bluetooth Low Energy (BLE) is used for IoT devices. ZigBee (802.15.4) serves low-power sensor networks.
Cellular Networks
Cellular networks divide geography into cells, each served by a base station. Generations: 1G (analog voice), 2G/GSM (digital voice, SMS), 3G (mobile data, video calls), 4G/LTE (high-speed broadband, IP-based), 5G (ultra-low latency, massive IoT, multi-Gbps). Each generation improves speed, capacity, and latency.
Mobile IP
Mobile IP allows a mobile device to move between networks while maintaining its IP address. It uses a home agent, foreign agent, and care-of address. When the mobile node moves, it registers with the foreign agent, and packets are tunnelled from the home agent.
Wireless Security
Wireless networks face eavesdropping, rogue access points, and man-in-the-middle attacks. Security protocols evolved from WEP (broken) to WPA to WPA2 (AES-CCMP) to WPA3 (SAE handshake). Enterprise networks use 802.1X authentication with RADIUS servers.
Ad Hoc and Mesh Networks
Ad hoc networks have no fixed infrastructure; nodes communicate directly and route for each other (MANET — Mobile Ad hoc NETwork). Mesh networks connect nodes in a mesh topology for redundancy and self-healing. Both are useful for emergency communication and IoT deployments.
IoT Networking
The Internet of Things (IoT) connects everyday objects to the Internet. IoT networking technologies include Wi-Fi, Bluetooth LE, ZigBee, LoRaWAN (long range, low power), NB-IoT, and MQTT protocol. Challenges include power constraints, scalability, and security.
Summary
Wireless and mobile networking is fundamental to modern communication. From Wi-Fi LANs to cellular networks and IoT, understanding wireless technologies, standards, and security is essential for BCA students.