Computer Networking: Wireless and Mobile Networks

• Wireless
  • Wireless links and network characteristics
  • Wi-Fi: 802.11 wireless LAN
  • Cellular networks: 4G and 5G
• Mobility
  • Principles
  • Practice

Wireless

Wireless links and network characteristics

• decreased signal strength
• interference from other sources
• multipath propagation
• hidden terminal problem
• signal attenuation

Wi-Fi: 802.11 wireless LAN

All use CSMA/CA for multiple access, and have base-station and ad-hoc network versions.

Collision Avoidance: RTS-CTS exchange

Cellular networks: 4G and 5G

• Mobile device
• Base station
• Home Subscriber Service
• Serving Gateway (S-GW)
• PDN Gateway (P-GW)
• Mobility Management Entity

Mobility

Principles

Let end-systems handle it: functionality at the “edge”

Practice

Major tasks

1. base station association
2. control-plane configuration
3. data-plane configuration
4. mobile handover