Types of Network

Mobile Phone

Cell Towers

Typically have 3 sectors, each operating at a different frequency so that they don't interfere with each other.

Cellular Backhaul

This is a connection between cell sites and switching offices (Mobile Telephone Switching Office - MTSO). The backhaul can be fiber, copper, or wireless

Early Web Access

A protocol was developed in early days to facilitate the viewing of websites on older mobile phones. The web pages were designed to support the underpowered browsers, running over UDP. The protocol was called WAP - Wireless Application Protocol.

Satellite Networks

A satellite network can be used for two stations on Earth to communicate. The sending Earth Station sends a transmission to the satellite. This stage is called uplink. The satellite transponds the signal and sends it down to the second Earth Station. This stage is called downlink.

Satellites in geostationary earth orbit (GEO) revolve around the Earth at the same speed as the Earth rotates. They maintain the same relative position over the surface of Earth.

Satellite networks serve a number of purposes:

  1. Fixed Service Satellites (FSS)
  2. Broadcase Service Satellites (BSS)
    • Satellite TV/Radio
    • Also called Direct Broadcast Service (DBS)
  3. Mobile Service Satellites (MSS)

Advantages and Disadvantages

  • The coverage area of a satellite network greatly exceeds that of a terrestrial system
  • Transmission cost of a satellite is independant of the distance
  • Satellite to satellite communication is very precise
  • Launcing satellites into orbit is costly
  • Bandwidth is limited
  • Large latency compared to terrestrial equivalents due to the much larger distance signals have to travel