ContentsContents

IntroductionIntroduction Definition Definition Development of wireless networkDevelopment of wireless network Kinds of networksKinds of networks Network componentsNetwork components OperationOperation ApplicationsApplications

INTRODUCTIONINTRODUCTION The increasing demands of the The increasing demands of the

voice & data end users are voice & data end users are driving the development of new driving the development of new networking techniques that networking techniques that accommodate mobile voice & accommodate mobile voice & data users who move data users who move throughout buildings,cities or throughout buildings,cities or countries. countries.

wireless networking

The term wireless networking refers to technology that enables two or more terminals to communicate using standard network protocols, but without network cabling. Strictly speaking, any technology that does this could be called wireless networking.

DEVELOPMENT OFWIRELESS NETWORKS

It is based on analog technology. The 1G cellular system uses FM modulation. 1G wireless system provide analog speech & inefficient , low rate data transmission. The speech signals are usually digitized using a standard time division multiplex format for transmission between the base station & MSC & from MSC to PSTN.

I. FIRST GENERATION:

II. SECOND GENERATION:

It employs digital modulation. examples of global wireless system include: GSM.TDMA, & CDMA US standards. It reduces computational burden of MSC by introducing base station controller (BSC) Inserted B/W several base stations & MSC’s. It provides dedicated voice & signalling trunks B/W MSC’s and MSC & PSTN. 2G wireless N/W specifically design to provide paging & other data services such as FAX & high data rate N/W access.

III. THIRD GENERATION:

The aim of 3G wireless N/W is to provide a single set of standards that can meet a wide range of applications & provide universal access. 3G use Broadband integrated service digital N/W (B-ISDN) which is a computer N/W framework designed around the concept of CCS. This generation N/W’s carry many type of information such as voice, data & video.

Kinds of wireless networks

1.Adhoc or peer-to-peer network.2.Wireless networking

with access point.

An Ad-Hoc, or Peer to Peer wireless network consists of a number of computers each equipped with a wireless networking interface card. Each computer can communicate directly with all of the other wireless enabled computers.

Each computer with a wireless interface can communicate directly with all of the others.

Ad-Hoc or Peer-to Peer Networking.

Infrastructure wireless network

A wireless network can also use an access point, or base

station. In this type of network the access point acts

like a hub, providing connectivity for the wireless

computers.

Types of access points

Hardware access points.

Software access points.

Hardware Access Point

Software Access Point

Wireless Networking Components

Stations: A station (STA) is a network node that is equipped with a wireless network device. Access points: A wireless AP is a wireless network node that acts as a bridge between STA and a wired network. Ports: A port is a channel of a device that can support a single point-to-point connection.

When a wireless adapter is turned on, it begins to scan across the wireless frequencies for wireless APs and other wireless clients in ad hoc mode. Next, the wireless adapter switches to the

assigned channel the selected wireless AP and negotiates the use of a port. This is known as establishing an association.

Wireless operation basics

Packet switchingConnectionless services exploit the

fact that dedicated resources are not required for message transmission. It is the most common technique used to implement connectionless services & allows a large number of data users to remain virtually connected to the same physical channel in the network.Packet switching breaks each message into smaller units for transmission & recovery.

A wireless computer can "roam" from one access point to another, with the software and hardware maintaining a steady network connection by monitoring the signal strength from in-range access points and locking on to the one with the best quality.

Roaming

A user can move from Area 1 to Area 2 transparently. The Wireless networking hardware automatically swaps to the Access Point with the best signal.

If the signal strength of the wireless AP is too low, the error rate too high.The signal can weaken as either the wireless adapter moves away from the wireless AP or the wireless AP becomes congested with too much traffic or interference.

By switching to another wireless AP, the wireless adapter can distribute the load to other wireless APs, increasing the performance for other wireless clients.

Roaming

Applications Applications

Satellite CommunicationSatellite Communication Wireless Local Loop (WLL)Wireless Local Loop (WLL) Cellular Wireless NetworkCellular Wireless Network Mobile IPMobile IP

Satellite communicationSatellite communication

The basis of a satellite The basis of a satellite communications system is a satellite communications system is a satellite based antenna in a stable orbit based antenna in a stable orbit above earth.above earth.

The antenna sys on or near earth are The antenna sys on or near earth are called EARTH STATIONS.called EARTH STATIONS.

Transmission from an earth station Transmission from an earth station to satellite is called UPLINK & from to satellite is called UPLINK & from satellite to earth station is called satellite to earth station is called DOWNLINKDOWNLINK

AdvantagesAdvantages

The area of coverageThe area of coverage The conditions are more time The conditions are more time

invariant thus having more invariant thus having more precisionprecision

Transmission cost is independent Transmission cost is independent of distanceof distance

Very high data rates are availableVery high data rates are available The quality of transmission is The quality of transmission is

extremely highextremely high

NetworkNetwork ConfigurationsConfigurations

Point to Point link :-Point to Point link :-

Satellite is used to provide point to Satellite is used to provide point to point link between two ground based point link between two ground based antennas.antennas.

Broadcast Link :-Broadcast Link :-

Satellite provides communication Satellite provides communication between one ground based transmitter & between one ground based transmitter & many receiversmany receivers..

BibliographyBibliography

Basic needs and Network TopologiesBasic needs and Network Topologies Networking Essentials (MCSE)Networking Essentials (MCSE) Computer Networks (Tanenbaum)Computer Networks (Tanenbaum) Network DevicesNetwork Devices Data communication and networkingData communication and networking (B.Forouzan)(B.Forouzan) Networking Essentials (MCSE)Networking Essentials (MCSE) ProtocolsProtocols Douglas C ComerDouglas C Comer Wireless Communication and Networks Wireless Communication and Networks

William Stallings William Stallings