Cellular Networks

Cellular NetworksCellular Networks

How do Mobile & Satellite Phones work?How do Mobile & Satellite Phones work?

What can we do with them?What can we do with them?

Learning Objectives:Learning Objectives:

By the end of this topic you should be able to:By the end of this topic you should be able to:

describe how a mobile phone network operates;describe how a mobile phone network operates;

describe the use of describe the use of cellularcellular andand satellite mobile satellite mobile phone systemsphone systems

describe the describe the advantages and disadvantagesadvantages and disadvantages of of cellularcellular andand satellite mobile phone systemssatellite mobile phone systems and and their use;their use;

describe how mobile technology and networks can  enable communication from anywhere in the world;

Mobile Communications topics:Mobile Communications topics:3.3.3 Networks and communications (16%, 20 marks) Jan

2010June 2010

Jan 2011

June 2011

Jan 2012

Jun 2012

Jan 2013

Jun 2013

k. describe how a mobile phone network operates (cellular and satellite) and the advantages and disadvantages of cellular and satellite mobile phone systems and their use;

X X X X 6? X X ?m. describe how mobile technology and networks

can enable communication from anywhere in the world;

- - - - - - X ?n. discuss the implications of being able to

communicate from anywhere in the world using mobile technology and networks;

X X 14? 16 X X X ?

3.3.4 Applications of ICT (16%, 20 marks) Jan 2010

June 2010

Jan 2011

June 2011

Jan 2012

Jun 2012

Jan 2013

Jun 2013

k. discuss the range of services offered by mobile communication services and the impact of these services on individuals and organisations;

- - - - - - X ?

How does that work……?How does that work……?1. Explain how a mobile phone networkmobile phone network works.

[4]

2. Describe how an call from a mobile telephone, anywhere in the UK, is routed to a landline telephone in Spain. [6]

3. Identify three limitations on the use of a mobile telephone. [3]

4. Describe how the emergency services can find the exact location of a mobile phone that is being used to make an emergency call in the UK. [6]

How does it happen?How does it happen?

Steps

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Terminology used:Terminology used:

Base Station TransceiverBase Station Transceiver

Terminology used:Terminology used: CellsCells

the area covered by a network is broken down into cells,the area covered by a network is broken down into cells, each cell has a Base Station Transceiver (each cell has a Base Station Transceiver (BSTBST),),

a mobile ‘phone mast that gives coverage to that cella mobile ‘phone mast that gives coverage to that cell Base Station Controllers (Base Station Controllers (BSCBSC))

manages communication between a set of BSTs and the MSCmanages communication between a set of BSTs and the MSC a Mobile Switching Centre (a Mobile Switching Centre (MSCMSC))

controls all of the calls taking place on the networkcontrols all of the calls taking place on the network

when a mobile phone moves into a new cell:when a mobile phone moves into a new cell: it registers with the BSCit registers with the BSC a database stores the current locations of mobile ‘phones a database stores the current locations of mobile ‘phones

Terminology used:Terminology used:

Calling a Mobile ‘PhoneCalling a Mobile ‘Phone caller dials the number caller dials the number from the mobile ‘phonefrom the mobile ‘phone mobile phone mobile phone sends a call request to a Base Station Transceiversends a call request to a Base Station Transceiver mobile mobile phone connects to BST phone connects to BST with the with the best signal best signal (nearest)(nearest) transceiver sends request to base station switching centre (transceiver sends request to base station switching centre (BSCBSC)) BSC connects to the Mobile Switching Centre BSC connects to the Mobile Switching Centre (MSC)(MSC) MSC MSC checks the caller’s statuschecks the caller’s status

enough credit to make the call?enough credit to make the call?

MSC MSC identifies which BSC identifies which BSC the receiving ‘phone is connected tothe receiving ‘phone is connected to by searching a by searching a databasedatabase (updated in real-time) (updated in real-time)

BSC sends a ‘request to dial’ BSC sends a ‘request to dial’ signal to all BSTs under its controlsignal to all BSTs under its control mobile phone receives the request and acknowledges it to the BSTmobile phone receives the request and acknowledges it to the BST call is connected by the MSCcall is connected by the MSC if user is if user is 'on the move'on the move' when making the call' when making the call

system detects this and system detects this and transfers call transfers call to next cellto next cell

Base Station Controller (BSC)Base Station Controller (BSC)

Base Station Controller (BSC)Base Station Controller (BSC)

Base Station Controller (BSC)Base Station Controller (BSC) BSC controls one or more base transceiver stations

(BTS) base stations or cell sites.

BSC is a high capacity sitch a BSC may have tens or hundreds of BTSs under its

control. a BSC communicates with the MSC The BSC handles allocation of radio channels, receives

measurements from the mobile phones, and controls handovers from BTS to BTS (except in the case of an inter-BSC handover in which case control is in part the responsibility of the anchor MSC).

networks are often structured to have many BSCs distributed into regions near their BTSs which are then connected to large centralised MSC sites.

Mobile Switching Centre (MSC)Mobile Switching Centre (MSC)

Mobile Switching Centre (MSC)Mobile Switching Centre (MSC) large cellular network will require multiple MSCs. MSC controls handovers between multiple BSCs on detecting that a mobile device is approaching the

edge of its cell, a BSC requests handover assistance from its MSC.

MSC then scans a list of adjacent cells and their corresponding BSCs and facilitates the handover to the appropriate BSC.

For this task, the MSC works with a large database known as the home location register (HLR), which stores relevant location and other information for each mobile phone.

Mobile Communication trendsMobile Communication trends not just voice datanot just voice data

SMS, email, Internet, IM, ….SMS, email, Internet, IM, …. higher bandwidth telecommunicationhigher bandwidth telecommunication

GPRS, 3G, 4GGPRS, 3G, 4G

convergence with other mobile technologiesconvergence with other mobile technologies ‘‘phone includes other devices (GPS, digital camera …)phone includes other devices (GPS, digital camera …)

PDA capabilitiesPDA capabilities address book, calendar, ….address book, calendar, ….

synchronisation with other computing devicessynchronisation with other computing devices = same, real-time data available on all devices & everywhere= same, real-time data available on all devices & everywhere

not just ‘phones not just ‘phones tablet devices, convertibles tablet devices, convertibles

Mobile ‘Phone FeaturesMobile ‘Phone Features digital cameradigital camera

still & video (video conferencing)still & video (video conferencing) media playbackmedia playback

mp3, video, radiomp3, video, radio high resolution, colour displayhigh resolution, colour display touch screen interfacetouch screen interface wireless connectivity – IR, Bluetooth, WiFiwireless connectivity – IR, Bluetooth, WiFi GPS / Satellite NavigationGPS / Satellite Navigation

Advantages & DisadvantagesAdvantages & Disadvantages

AdvantagesAdvantages

mobile phones can be used mobile phones can be used anywhere there is a signal anywhere there is a signal users are not restricted to sitting in an users are not restricted to sitting in an

office or at home to make and receive office or at home to make and receive calls calls