NES440: Wireless Networks
Copyright © Dr. Fahed H. Awad
1
Wireless WANs:
Cellular Networks
NES440 Wireless Networks
Cellular Telephone Systems
Cellular telephone systems were originally designed to provide voice
communications services to/from mobile stations (MS)
A MS can communicate to another MS or to a landline stationary station
The cellular structure is designed such that:
The service area is divided into small regions called “cells”
Each cell has a base station (BS) that provides the first hop access for the MS
Each BS is connected to a call switching office called the Mobile Switching Center (MSC)
The MSC connects the BS with other BS’s and to the Public Switched Telephone Network (PSTN)
The cellular service provider must be able to:
Track and locate the MS within its coverage (or service) area
Assign a channel to each call from or to the MS
Maintain the call as the MS moves around
Copyright © Dr. Fahed H. Awad
2
NES440: Wireless Networks
Mobile
Switching
Center (MSC)
Public Switched
Telephone Network
(PSTN), and the
Internet
Mobile
Switching
Center (MSC)
Components of the Cellular Network Architecture
Connects the cells to the wide area network
Manages call setup (more later!)
Handles mobility (more later!)
MSC
Wired Network
Cell
Covers a geographical region
Base Station (BS)
: analogous
to the IEEE 802.11 AP
Mobile Station (MS)
: attaches
to the network through the BS
Air-interface
: the physical and
link layer protocols between the
MS and the BS
Copyright © Dr. Fahed H. Awad
3
NES440: Wireless Networks
