Chapter 2

Basics of WirelessNetworks

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Learning objectives

Tounderstand wireless networks

To know the access technologies

To study problems such as interference, multi-pathpropagation, path loss, battery life, etc.

To illustrate issues like channel allocation, routing,mobility, security, power management, etc.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless networks

Wired network Wire as communication High data rate No mobility

medium

Wireless network Radio waves and Less data rate Highly portable Mobility

air as a medium

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless networks (Contd..)

ProvideInternet

inexpensive and rapid connection setup with

Restricted by distance

Overlapping

radio cells to provide connectivity

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network architecture

It consists of mobile hosts, fixed hosts, access stations (BS),core network to support mobility and switching.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network architecture (Contd..)Mobile host

Laptop, mobile phone, PDA, notebook, etc. canmove from one place to another place whilemaintaining connection with wireless network.

Fixed wireless host Cannot move but the medium is radio waves. Example: wireless web servers, printers, etc.

Access Network Consists of access stations (BS) which provide

services to hosts reachable from it.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network architecture (Contd..)Core Network

Consists of active components that performdata switching between access stations (BS),and provide location and mobility services.

Facilitates communication from mobile host tomobile host, mobile host

fixedto wired node, fixed

host,hostetc.

to wired node, host to mobile

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless networks

Wireless

Wireless

Wireless

Wireless

Wireless

body area networks

personal area networks

local area networks

metropolitan area networks

wide area networks such as

andGSM or

CDMA cellular networks

Satellite networks and broadband

access networks

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless(Contd..)

networks

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless(Contd..)

Wireless Body Area Network (WBAN)

networks

Max. signal range 2 meters

Interconnecting respective devices within the surface of the body

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless(Contd..)

networks

Wireless Body Area Network (WBAN)

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless(Contd..)

networks

Wireless Personal Area Network (WPAN)

Max. signal range of 10 meters

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless networks(Contd..)

Wireless Local Area Network (WLAN)• Signal range is ≈100 meters.• Also called the Wireless Fidelity (Wi-Fi or IEEE 802.11)

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Recall: an example of wired LAN

Station

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Work

PrinterServer

Laptop

WorkStation

LaptopLaptop

WorkStation

An example of wireless LANA user is connected ifhe/she is in the coveragearea of a cell

Each cell operates at adifferent frequency

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

WorkStation

WorkStation

WorkStation

WorkStation

WorkStation

PrinterServer

AccessPoint

AccessPoint

AccessPoint

AccessPoint

AccessPoint

AccessPoint

Laptop Laptop LaptopLaptopLaptopWorkStation

Classification of wireless networks(Contd..)

Wireless Metropolitan Area Network (WMAN) Signal range of approximately 5 km to 20 km (recently up to 50

km) Often called Worldwide Interoperability for Microwave Access(WiMAX or IEEE 802.16)

Wi-Fi usersmay beconnected to the WiMAXnetwork

WiMAX BS

Mobile devicesmight have built in WiMAXadapter or may be externally plugged

WMAN mightbe owned and operated byorganizations or public institutions

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Classification of wireless networks(Contd..)

Wireless Wide Area Network (WWAN) Use network infrastructure of mobile operators. Cover wide area much wider than groups mentioned above. Use cellular network technologies such as WI-MAX, GSM, GPRS,

3G and others.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless switching technologyPacket switching is the basic type oftechnology Uses short bursts of information,

wireless switching

uses channels onlyfor short periods of time.

protocols. Standard routing

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Recall: Packet switching

2ndFrom W. Stallings, Wireless Communications and Networks, Edition

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Recall: Packet switching (Contd..)

From W. Stallings, Wireless Communications and Networks, 2nd Edition

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless switching technology (Contd..)

- Packets are routed and pipelined using multiplexing

- Bandwidth is used only when data is transmitted

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless switching technology (Contd..)

Virtual circuit Switched virtual circuits (SVCs) Established dynamically on demand

3 phases – circuit establishment,termination

data transfer, circuit

Permanent virtual circuits

(PVCs)transfer Only one mode i.e., data

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless communication

Increased bit error rate Lower transmission power Scattering Reflection Diffraction

problems

Multipath propagation Path loss

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless communication problemsIncreased bit error rate

Wireless network media is more prone to obstacles between Tx and Rx Interference from neighbour nodesOne can observe

errors due to

Frequent disconnections causing to data loss Annoying to voice and video clients

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless communication problems (Contd..)Lower transmission power Mobile units powered by battery have scarce energy resources Limited transmission power to avoid interference Attenuation

Capture power at the receiver side is Pr = Pt / (4 πd / l)2

Where Pt is the transmitter power, d the distance betweenand the receiver, and l is the wavelength of the signal.Lp = (4 πd / l)2 is the path loss.

Scattering

the transmitter

Occurs when signal pass through the object whose dimension issmaller than the wavelength.

Scattered waves are produced by rough surfaces, small objects,irregularities in the channel. Needreduce it.

proper deployment strategies to

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless communication problems(Contd..)

Reflection Occurs when electromagnetic wave strikes an object which has very large dimension compared to the wave length. Ex: walls, furniture,buildings, etc.

Diffraction Occurs when radio path between Tx and Rx is obstructed by surfaces

thatwill

have sharp irregularities (edges) causing secondary waves, whichbe present in space and behind the obstacle.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless communication problems(Contd..)

Multipath Propagation Caused by reflection and scattering

Radio waves arrive at the Rx from differentdelays Final signal is the summation of all signals

directions with varying

Antenna diversity methods

are used to overcome this problem

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network reference model

TheOSI

TCP/IP architecture is functionally equivalent to thereference model.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Recall: TCP/IP Concepts

2ndFrom W. Stallings, Wireless Communications and Networks, Edition

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Protocol Data Units in the TCP/IPArchitecture

Examples:TCP header includes destination port, sequence number, checksumIP header includes destination host address (B in previous example)Network header includes destination subnetwork addressFrom W. Stallings, Wireless Communications and Networks, 2nd Edition

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network reference model(Contd..)

Major similarities and differences betweenTCP/IP and the OSI reference models are Both models have an application, atransport, and a network/Internet layer

The TCP/IP model does not have asession layer

Lower layers connects the upper layersto the actual physical network

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network reference model(Contd..)

Application layer functions This is the layer where end user applications such as remote login,

mail transfer, file transfer, network management, and web browsers

run Transport layer functions

Its job is to provide reliable communication from application toapplication (end-to-end) regardless ofcommunication links It encapsulates application layer data layer

the lower-layer protocols and

and deliver it to the network

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Illustration of the transport service

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Wireless network reference model(Contd..)

Data link layer functions

This includes the logical link control (LLC) sublayer andMAC (media access control) sublayer.

the

It does segmenting the bit stream into frames, error handling,flow control, and access control.

MAC ischannel

responsibleand reliable

for accessing and sharing of the wirelessdelivery by using acknowledgments.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

Illustration of data link layer

Bridge

802.4 LLC P

802.4 LLC P

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.

802802.3 LLC P

LLC P

802.3 LLC P 8024 LLC P

802.3 LLC P 802

Computer A

P

LLC P

802.3 LLC P

802.3 LLC P

Computer B

P

LLC P

802.4 LLC P

802.4 LLC P

Wireless network reference model(Contd..)

Physical layer functions This layer transports encapsulated data from the data linktransmits it wirelessly to the distant network.

layer and

The wireless features and functionality (modulation type, data rate,and so on) take place at this layer.

These slides are based on the slides formatted by Dr Sunilkumar S. manvi and Dr Mahabaleshwar S. Kakkasageri, the authors of the textbook: Wireless and Mobile Networks, concepts and protocols. See slide number one.