Cellular Telephony Final

8/4/2019 Cellular Telephony Final

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CELLULAR TELEPHONY

Prepared by: L. Macam


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MOBILE TELEPHONY

First Generation (1G) systems

were analog with reasonably reliablenetworks but limited service offerings and did

not permit roaming between networks.


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MOBILE TELEPHONY

Second Generation (2G) mobile systems

are digital and bringsignificant advantages interms of sophistication,capacity and quality.

GSM

GPRS

Other standards and features:

Intelligent network (IN) feaures

mobile positioning features

SMS (Short Message Service)


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MOBILE TELEPHONY

Third Generation systems

Will allow

communication,information andentertainment servicesto be delivered via

wireless terminals.

Example:

Universal Mobile Telecommunication

Systems (UMTS)


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1G 2G 3G

Analog Cellular Digital Cellular Digital Cellular

Voice Voice/data Voice/high-speed data

AMPS CDMA 1XRtt CDMA2000

TACS GSM GPRS W_CDMA

80 1992 1999 2001 2003

AMPS Advanced Mobile Telephone System

TACS Total Access Communication SystemCDMA Code Division Multiple Access

GSM Global System for Mobile Communication

GPRS General Packet Radio Service


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HISTORY OF WIRELESS COMMUNICATION

Date Activity

1906 Reginald Fesseden successfully transmitted human voice over radio.

1915 J. A. Fleming invents the vacuum tube making it possible to build mobile

radios.

1921 One-way radio messaging service started by Detroit Police Department. It

used a 2Mhz frequency in the departments first vehicular mobile radio.

1930s Amplitude Modulation (AM), two-way mobile systems in place in the US

took advantage of newly developed mobile transmitters and push-to-talk

halfduplex transmission.

1935 FM radio was patented; Edwin H. Armstrong invented it. FM uses frequencymodulation of the radio wave to minimize static and interference from

electrical equipment and the atmosphere, in the audio program.

1940s FCC recognizes mobile radio as new class of service as Domestic Public

Land Mobile (DPLM) radio service.


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Date Activity

1947 D.H Ring working at Bell Laboratories, envisions the cellular concept.

1948 Shockley, Bardeen and Brittain at Bell Laboratories, invent the transistor

which enables electronic equipment including radio to be miniaturized.

1949 Radio Common Carriers (RCCs) were recognized.

1958 Bell Systems made broadband proposals.

1964 AT&Ts Improved Mobile Telephone Service (IMTS) eliminated the need

for push-to-talk operation and offered automatic dialing.

1968 The Federal Communications Commission (FCC) opened Docket 18262

to address questions regarding spectrum reallocation.

1969 The first comprehensice international standardization group was formed.

Nordic Mobile Telephone (NMT) group is composed of Nordic countries.

1973 The NMT group specifies a feature allowing mobile telephones to be

located within and across networks. This becomes the basis for roaming.


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Date Activity

1979 FCC authorized experimental cellular systems launched in Chicago and the

Washington, D.C./Baltimore region.

1981 Ericsson launches the worlds first cellular system in Saudi Arabia based on

the analog NMT 450 standard.

1991 The first digital cellular standard (GSM) is launched.

1998 Mobile subscribers world-wide number 200 million.

1999 The GPRS packet data standard released.

2000 First 3G test network built in Monaco, Isle of Man and Sweden and first 3G

licenses auctioned in UK

2001 First successful test calls made on 3G networks

2002 TDMA networks in the Americas moving to GSM


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MAIN CELLULAR STANDARDSYear Standard Mobile Telephone System Technology Primary Markets

1981 NMT 450 Nordic Mobile Telephony Analogue Europe-Middle

East

1983 AMPS Advanced Mobile Phone

System

Analogue North and South

America

1985 TACS Total Access Communication

System

Analogue Europe and

China

1986 NMT 900 Nordic Mobile Telephony Analogue Europe-Middle

East

1991 GSM Global System for Mobile

communication

Digital World-wide

1991 TDMA

(D-AMPS)

(IS136)

Time-Division Multiple

Access

(Digital-AMPS)

Digital North and South

America

1993 CdmaOne

(IS95)

Codedivisionmultipleaccess

One

Digital N. America

Korea


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MAIN CELLULAR STANDARDS

Year Standard Mobile Telephone System Technology Primary Markets

1992 GSM 1800 Global System for Mobile

communication

Digital Europe-Middle

East

1994 PDC Personal Digital Cellular Digital North and South

America

1995 PCS 1900 Personal Communication

Services

Digital Europe and

China

2001 GSM 800 Global System for Mobile

communication

Digital Europe-Middle

East


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GSM NETWORK

COMPONENTS

AuC Authentication Center

BTS Base Transceiver Station

HLR Home Location Register

MSC Mobile services

Switching Center

BSC Base Station Controller

EIR Equipmenr Identity

Registry

MS

Mbile Station

VLR Visitor Location Register


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GSM NETWORK COMPONENTS


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SWITCHING SYSTEM COMPONENTS

Mobile services Switching Center (MSC)

performs the telephony switching functions for the mobile

network.

It controls calls to and from other telephony and data

systems.

Gateway Functionality

- Gateway functionality enables an MSC to interrogate a

networks HLR in order to route a call to a Mobile Station

(MS).


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Home Location Register (HLR)

- a centralized network database that stores and

manages all mobile subscriptions belonging to a

specific operator.

The information stored includes:

Subscriber identity

Subscriber supplementary services Subscriber location information

Subscriber authentication information


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Authentication Center

(AuC)

- it authenticates thesubscribers attempting to

use a network.


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Equipment Identity Register (EIR)

- a database containing mobile equipmentidentity information which helps to blockcalls from stolen, unauthorized, ordefective MSs.


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BASE STATION COMPONENTS

Base Station Controller (BSC)

- it manages all the radio-related functions of a GSM

network.

- it is a high capacity switch that provides functions

such as MS handover, radio channel assignment andthe collection of a cell configuration data.


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BASE STATION COMPONENTS

Base Transceiver Station

- controls the radio interface to the MS.

- comprises the radio equipment such as

transceivers and antennas which are needed

to serve each cell in the network.


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NETWORK MONITORING CENTERS

Operation and Maintenance Center (OMC)

- a computerized monitoring center which isconnected to other network components.

- the status of the network and can monitor and

control a variety of system parameters.


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NETWORK MONITORING CENTERS

Network Management Center (NMC)

- centralized control of the network is done here

- only one NMC is required for a network and this

controls the subordinate OMCs.


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MOBILE STATION (MS)

An MS is used by a mobile subscriber to

communicate with the mobile network.

GSM MSs consists of: A mobile terminal

A Subscriber Identity Module (SIM)


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GSM GEOGRAPHICAL NETWORK

STRUCTURE

CELL

A cell is the basic unit of a cellular system

and is defined as the area of radio coverage

given by one BS antenna system.

Each cell is assigned a unique number called

Cell Global Identity (CGI).


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CELL

The hexagon shape was chosen because it

provides the most effective transmission by

approximating a circular pattern while eliminating

gaps inherently present between adjacent circles.


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CELL

The physical size of a cell varies depending on a userdensity and calling patterns.

Macrocells (large cells) typically have a radius between 1

mile and 15 miles with base station transmit powersbetween 1w and 6w.

Microcells (smallest cells) typically have a radius of 1500feet or less with base station transmit powers between

0.1W and 1W.

Picocell is used indoors, where cellular radio signals areweek to provide reliable communications.


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LOCATION AREA (LA)

A Location Area is defined as a group of cells.Within the network a subscribers location islinked to the LA in which they are currently

located.

The identity of the current LA is stored in the VLR.


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MSC SERVICE AREA

An MSC service area is made up of a number of Las andrepresents the geographic part of the networkcontrolled by one MSC.

The subscribers MSC service area is stored in the HLR.


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PLMN SERVICE AREA

A Public Land Mobile Network (PLMN) servicearea is the entire set of cells served by onenetwork operator and is defined as the area inwhich an operator offers a radio coverage and

access to its network.


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GSM SERVICE AREA

The GSM service area is the entire geographical area inwhich a subscriber can gain access the to a GSM networkto.

The GSM service area increases as more operators signcontracts agreeing to work together.

GSM Service Area


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GSM FREQUENCY BANDS

As GSM has at fogrown worldwidw, it has expandedto operate ur main frequency bands: 900, 1800, 1900and 800.


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WIRELESS CONCEPTS

Channels A channel is a frequency or set of frequencies which

can be allocated for the transmission, and possibly thereceipt, of information.

It is an important factor in determining the capacity ofa mobile system.

TYPE DESCRIPTION EXAMPLES

Simplex One way only FM radio television

Half-duplex Two way, only one at a

time

Police radio

Full-duplex Two way, both at the

same time

Mobile systems


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Duplex Distance

The use of full duplex requires that uplink and

downlink transmission are separated in

frequency by a minimum distance.


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Carrier Separation

Every mobile system includes a carrier separation.

This is the distance on the frequency band betweenchannels being transmitted in the same direction.

This is required to avoid overlapping of information

in one channel into an adjacent channel.

In GSM the carrier separation is fixed at 200 kHz.


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Capacity and Frequency Re-use

It is the number of frequencies in a cell thatdetermines the cells capacity.

A cell may have one or more frequenciesallocated to it. It is important when allocatingfrequencies that interference is avoided.

A common factor is the use of similarfrequencies close to each other.


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Capacity and Frequency Re-use

The same frequencies can not be used in neighboring cellsas they would interfere with each other, so special patternsof frequency usage are determined during the planning ofthe network.

The term frequency re-use distance is used to describebetween two identical frequencies in a re-use pattern.


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Transmission Rate

The amount of information transmitted over aradio channel over a period of time is knownis the transmission rate.

Transmission rate is expressed in bits persecond or bit/s.

In GSM the net bit rate over the air interface is270kbit/s.


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Access Method: TIME DIVISION

MULTIPLE ACCESS (TDMA)

Most digital cellular systems use the technique of TimeDivision Multiple Access (TDMA) to transmit andreceive speech signals.

With TDMA, one carrier is used to carry a number ofcalls, each call using the carrier at designated periodsin time. These periods of time are referred to as timeslots.

Each MS on a call is assigned one time slot on theuplink frequency and one on the downlink frequency.Information sent during one time slot is called a burst.


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Access Method: TIME DIVISION

MULTIPLE ACCESS (TDMA)

In GSM, a TDMA frame consists of 8 time

slots. This means that a GSM radio carrier can

carry 8 calls.


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Roaming and Handsoffs

Roaming is when a mobile unit moves from

one cell to another possibly from one

companys service area into another

companys service area.


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The transfer of a mobile unit from one base stationscontrol to another base stations control is called ahandoff (or handover).

A hard handoffis a break-before-make process; themobile unit breaks its connection with one base stationbefore establishing a voice communication with a newbase station.

A soft handoffis a flawless handoff that normally takesapproximately 200 ms, which is imperceptible to voicetelephone users.


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Transmission Problems

Path loss occurs when the received signal becomes weakerand weaker due to increasing distance between MS andBTS, even if there are no obstacles between thetransmitting (Tx) and receiving (Rx) antenna.

Shadowing occurs when there are physical obstacles

including hills and buildings between BTS and the MTS.

PATH LOSS

SHADOWING


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Rayleigh fading

MULTIPATH FADING

Transmission Problems

Multipath fading occurs when there is more than one transmissionpath to the MS or BTS, and therefore more than one signal is arrivingat the receiver.

This occurs when a signal takes more than one path netween the MSand BTS antennas. Rayleigh fading occurs when the obstacles areclose to the receiving antenna.


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Solutions to Transmission Problems

BER defines the percentage of the total number ofreceived bits which are incorrectly detected.

Channel coding is used to detect and correct errors in a

received bit stream. It adds bits to a message.These bits enable a channel decoder to determinewhether the message has faulty bits.

Bit Error Rate

CHANNEL CODING


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With AMR, the rate of channel coding bits and

the underlying speech codec rate can be adaptedto suit the prevailing radio environment.

AMR consists of a number of different codecs,which with the associated channel coding hasbeen optimized for different radio environments.

ADAPTIVE MULTIRATE


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Interleaving is a process used to separate

consecutive bits of a message so that these

are transmitted in a nonconsecutive way.

INTERLEAVING


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Antenna Diversity increases the received signal strengthby taking advantage of the natural properties of radio

waves.

An increased received signal strength at the BTS may be

achieved by mounting two receiver antennae insteadof one. If the two Rx antennae are physically separatedthe probabilty that both of them are affectec by deepfading at the same time is low.

ANTENNA DIVERSITY

Space Diversity


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With polarization diversity the two space

diversity antennae are replaced by one dual

polarized antenna. The most common types

of ploarized antenna rays are

vertical/horizantal and are in 45 degree slant

orientation.

Polarization Diversity


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It is possible for the BTS and MS to hop from frequency tofrequency during a call. The frequency hopping for theBTS and MS is synchronized.

In GSM there are 64 patterns of frequency hopping; oneof them is a simple cyclic or sequential pattern. Theremaining 63 are pseudo-random patterns, which anoperator can choose from.

FREQUENCY HOPPING


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Two types of hopping are supported by the

BSC:

BASEBAND hopping involves hopping between

frequencies on different tranceivers in a cell

SYNTHESIZER hopping involves hopping from

frequency on the same tranceiver in a cell.


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CDMA: Code-Divison Multiple Access

Also known as IS-95 (Interim Standard 95),proposed by Qualcomm as a cellular telephonesystem and standard based on spread spectrumtechnology with the primary goal of increasingcapacity.

CDMA allows users to differentiate from one

another by a unique code rather than a frequencyor time assignment.


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The transmission medium is a resource that can be subdivided intoindividual channels according to the technology used.

FDMA : Frequency Division Multiple Access A channel is a frequency

Each user on a different frequency

TDMA: Time Division Multiple Access

A channel is a specific time slot on a specific frequency

Each user on a different window period in time (timeslot) CDMA: Code Division Multiple Access

A channel is a unique code pattern

Each user uses the same frequency all the time, but mixed withdifferent distinguishing code patterns

Channel: An individually-assigned, dedicated pathway through

a transmission medium for one users information.


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Each mobile user with a given cell, and mobilesubscribers in adjacent cells use the same radio-frequency channel.

This is made possible because of direct-sequence,spread-spectrum CDMA system and does not followthe channelization principles of traditional cellularradio communication systems.

Interference is incorporated into the system so thatthere is no limit to the number of subscribers that itcan support.


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Subscribers data change in real time,

depending on the voice activity and

requirements of the network and other users

of the network.

IS-95 also specifies a different modulation

and spreading technique for the forward andreverse channels.


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On the forward channel, the base station simultaneously transmit

user data from all current mobile units in that cell by using different

spreading sequences for each users transmission.

On the reverse link, all mobile units respond in an asynchronousmanner with a constant signal level controlled by the base station.


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CDMA reduces the importance of frequency planningwithin a given cellular network. Each CDMA channel isallocated a 1.25 Mhz frequency sprectrum for each one-way CDMA communications channel.

With CDMA, users can share common transit and receivechannel with a transmission data rate of 9.6 kbps.

Subscriber information is spread by a factor of 128 to achannel chip rate of 1.2288 Mchips/s, and transmit and

receive channels use different spreading process.

Uplink channel data streams are encoded using a rate convolution code while downlink channel are encodedusing a rate 1/3 convolution code.


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Frequency-Hopping Spread Spectrum (FHSS)

Each users narrowband signal hops among discrete frequencies,

and the receiver follows in sequence

Is NOT currently used in wireless systems, although used in the

military

Direct Sequence Spread Spectrum (DSSS)

Narrowband input from a user is coded (spread) by a user-

unique broadband code, then transmitted

Broadband signal is received; receiver knows, applies users

code, recovers users data

Is the method used in CDMA commercial systems


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CELL PLANNING

Cell planning can be described as all activities

involved in:Selecting the sites for the radio equipmentSelecting the radio equipment

Configuring the equipment

Every cellular network requires cell planning inorder to provide adequate coverage and callquality.

INTRODUCTION


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CELLS

A cell may be defined as an area of radiocoverage from one BTS antenna system.

It is the smallest building block in a mobilenetwork and is the reason why mobile nteworksare often referred to as cellular networks.

Typically, cells are represented graphically byhexagons.


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Two Main Types of Cell

OMNI DIRECTIONAL CELLAn omnidirection cell (or omnicell) is served by a BTS

with an antenna which transmits equally in alldirections (360 degrees).

Typically used to gain coverage


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Two Main Types of Cell

SECTOR CELLA sector cell is the area of coverage from an antenna,

which transmits, in a given direction only. This may beequal to 120 degrees or 180 degrees of an equivalent

omni-directional cell.Two-sectored sites and three-sectored sites

Typically used to gain capacity


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CELL PLANNING PROCESS

The major activities involved in the cell planning process are shown below.


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[1] TRAFFIC AND COVERAGE ANALYSIS

The cell planning process is started by a traffic and

coverage analysis.

The analysis should produce information about the

geographical area and the expected capacity need.


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The Erlang (E) is a unit of measurement of traffic intensity.

It can be calculated with the following formula:


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The geographical distribution of the traffic

demand can be calculated using demographic

data, such as:

Population distribution Car usage distribution

Income level distribution

Land usage data

Telephone usage statistics Other factors, such as subscription charges, call

charges, and costs of mobile stations


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Calculation of required number of BTSs

To determine the number and layout of BTSs the number of

subscribers and the Grade Of Service (GOS) have to be known.

The GOS is the percentage of allowed congested calls

and defines the quality of the service.


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[2] NOMINAL CELL PLAN

A sample planning tool, Test Mobile System (TEMS)

CellPlanner, includes a prediction package which

provides:

coverage prediction

composite coverage synthesis

co-channel interference predictions

adjacent channel interference predictions



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For example, if there are doubts about the risks

of time dispersion at a particular site the

following steps could be taken:

o The site location could be changedo The site could be measured with respect to time

dispersion

o The site could be analyzed with a carrier-to-

reflection ratio (C/R) prediction tool


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In reality, hexagons are extremely simplifiedmodels of radio coverage patterns because radio

propagation is highly dependent on terrain andother factors.

The problems of path loss, shadowing andmultipath fading all affect the coverage of anarea.

Radio propagation


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The maximum radius of a GSM cell is 35km.

In areas where large coverage with small capacity

is required, it is possible to allocate twoconsecutive TDMA time slots to one subscriberon a call.

This enables a maximum distance from the BTS of70km.


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A fundamental principle in the design of

cellular systems is the frequency reusepatterns.

Frequency Reuse is defined as the use ofradio channels on the same carrier frequency,covering geographically different areas.

Frequency Re-use


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Co-channel Interference (C/I)The carriertointerference ratio (C/I) is defined as the

ratio of the level of the received desired signal to the levelof the received undesired signal.

This C/I ratio is dependent on the instantaneous positionof the mobile and is due to irregular terrain and variousshapes, types and numbers of local scatterers.

GSM states C/I > 9dB, with frequency hoppingimplemented, and recommends C/I > 12dB whenfrequency hopping is not employed.

Interference

[ ]


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This C/I ratio is influenced by the following factors:

The location of the MS

Local geographical and type of local scatter

BTS antenna type, site elevation and position

[ ]


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Adjacent channel interference (C/A) The carriertoadjacent ratio (C/A) is defined as the relation in dB in

signal strength between the serving and an adjacent frequency.

The GSM specification states that the carrier-to-adjacent ratio (C/A)must be larger than -9dB. It is recommended that higher than 3dB

be used planning criterion.

[ ]


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A cluster is a group of cells available frequencies

have been once and only once.

The re-use pattern recommended for GSM are the

4/12 and the 3/9 pattern. 4/12 means that there

are four three-sector sites supporting twelve cells

using twelve frequency groups.

Cluster

[2] NO INAL C LL LAN


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The 4/12 cell pattern is in common use by GSMnetwork operators.



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In the 3/9 cell pattern there are always 9 channelsseparating each frequency in a cell.

[3] SURVEYS


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[3] SURVEYS

Site surveys are performed for all proposed site

locations. The following must be checked for eachsite:

Exact location

Space for equipment, including antennas

Cable run

Power facilities

Contract with site owner

Site Surveys

[3] SURVEYS


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[3] SURVEYS

Radio measurements are performed to adjust theparameters used in the planning tool to reality. That is,

adjustment made to meet the specific climate and terrainrequirements.

A test transmitter is mounted on a vehicle, and signalstrength is measured while driving around the site area.

Afterwards, the results from these measurements can becompared to the values the planning tool produced whensimulating the same type of transmitter.

Radio measurements

[4] SYSTEM DESIGN


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[4] SYSTEM DESIGN

Once the planning parameters have beenadjusted to match the actual measurements,dimensioning of the BSC, TRC and MSC/VLR canbe adjusted and the final plan produced.

As the name implies, this plan can then be usedfor system installation.

[5] & [6] IMPLEMENTATION AND


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[ ] [ ]

TUNING

System installation, commissioning, and testing areperformed following the final cell planning and

system design.

[5] & [6] IMPLEMENTATION AND


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[ ] [ ]

TUNING

Once the system has been installed, it is continuously

monitored to determined how well it meets demand.

This is called system tuning. It involves:

Checking that the final plan was implemented successfully

Evaluating costumer complaints

Checking that the network performance is acceptable

Changing parameters and taking other measurements, ifnecessary

[7] SYSTEM GROWTH/CHANGE


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The feature HEIRARCHICAL CELL STRACTURE (HCS)divides the cell network into up to 8 layers. The

higher are used for larger cells and the lower layersfor small cells.

The different cell layers can be seen as a prioritydesignation with the lower layer as the highestpriority. Thus, when selecting a BCCH carrier, an MSwill choose an acceptable signal, in as low a layer aspossible.

HEIRARCHICAL CELL STRACTURE (HCS)



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The OVERLAID / UNDERLAID SUBCELLS features provides away to increase the traffic capacity in a cellular networkwithout building new sites.

A set of channels in a BST is assigned to transmit at acertain power level. These are the under laid subcellchannels.

Another set of channels in the same BTS is assigned totransmit at a lower power level. These are the overlaidsubcells channels.

OVERLAID / UNDERLAID SUBCELLS



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The main overlaid subcell goal of the feature BCCH inOverlaid subcell is to allow tighter re-use of BCCHcarrier frequencies.

This is achieved by configuring a BCCH carrier in theOverlaid subcell and distributing the TCH trafficbetween Overlaid and Underlaid subcells.

To ensure that the BCCH can be received in the wholecell, the output power of the BCCH carrier in theoverlaid subcell shall be the same as if it had been inthe underlaid subcell.

BCCH IN OVERLAID SUBCELL



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Introducing BCCH in overlaid subcell, in a

network where the BCCH is not frequency

hopping, it gives the following benefits:

Possibility to substantially tighter the frequency reusefor the no hopping BCCH carrier.

Reduced need for investment in new sites/cells due toincreased capacity in existing cells.

Better speech quality since frequency hopping trafficchannels will used at the cell borders.

BCCH-frequency used for traffic in a smaller cell area,that is the overlaid area (OL)

Review Questions


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Review Questions

1. Using a cellular phone outside your home service area

a. Long distance communications

b. Roaming

c. Global communications

d. Jamming

2. What is the meaning of AMPS which is the standard for analogue cellular

telephones?

a. Advanced mobile phone service

b. Automatic mobile phone system

c. Analog Mobile passband system

d. Amplitude Mixing phone standard

Review Questions


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Review Questions

3. The time spent on a cellular telephone which is usually billed to thesubscriber on a per minutes system.

a. Time division system

b. Airtime

c. Duration

d. Interval

4. Channel is known as the width of the spectrum which is measured in

kilohertz (kHz). What is the width of the channel used by most analog

cellular phones?a. 50kHz

b. 60kHz

c. 40kHz

d. 30kHz

Review Questions


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Review Questions

5. A digital technology that uses a low power signal spread across a widebandwidth. With this technology, a phone call is assigned a code instead ofa certain frequency. Using the identifying code and a low power signal, alarge number of callers can use the same group of channels.

a. Time division multiple access

b. Pulse code division multiplexing

c. Pulse multiple accessd. Code division multiple access

6. A central computer that connects a cellular phone call to the publictelephone network. It controls the entire systems operation, includingmonitoring calls, billing and handouts.

a. Personal communications services

b. Wide area network computer

c. Mobile telephone switching office

d. International standards organization

Review Questions


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Review Questions

7. What is the meaning of IS-54 which is the dual mode (analog and digitalcellular standard in North America?) in the analog mode, this conforms to

the Advanced Mobile Phone Service.

a. Interim standard number 54

b. International standard number 54

c. Integrated system number 54

d. Industry standard number 54

8. A phone that operates on both analog and digital networks.

a. Dual systemb. Coupled system

c. Paired-mode system

d. Dual-mode system

Review Questions


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Review Questions

9. The geographic area by a single low-power transmitter/receiver. Itcategorizes a cellular systems service area.

a. Channel

b. Service area

c. Site

d. Cell

10. Radio frequencies assigned in one channel in a cellular system are limited

to boundaries of a signal cell because of their low power. The carrier is

free to use the frequencies again in other cells in the system withoutcausing interference. What do you call this method?

a. Frequency assignment

b. Channel utilization

c. Frequency reuse

d. Optimum frequency assignment

Review Questions


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Review Questions

11. A loosely defined future universal telecommunications services that willallow anytime, anywhere voice and data communication with personalcommunication devices.

a. Personal communication system

b. Universal telephone services

c. Personal handy phone

d. Nation wide communication services

12. A special fee that local telephone companies are allowed to charge alltelephone costumers for the right to connect with the local phonenetwork.

a. Airtime fee

b. Access fee

c. Connection fee

d. Mandatory fee

Review Questions


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Review Questions

13. A means of increasing the capacity of a cellular system by subdividing orsplitting cells into two or more smaller cells.

a. Spectrum allocation

b. Cell allocation

c. Channel splitting

d. Cell splitting

14. A process that provides security for wireless information. Information is

encoded so that it can be ready by a device with a matching decoding

procedure.a. Wireless decoder

b. Cellular decoder

c. Encryption

d. decoder

Review Questions


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Review Questions

15. An important safety features thats included with most of todays carphones. It permits the driver to use his cellular car phone without lifting or

holding the headset to his ear.

a. Hands-free

b. Hands-off

c. Handy phone

d. Safety phone

16. A cellular phone features that automatically blows the cars horn if a calls

comes in, alerting the recipient standing nearby.a. Alert mode

b. Warning horn

c. Call horn

d. Alert mode

Review Questions


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Review Questions

17. An important feature of a cellular phone subscribing of a voice mail whichindicates a light or other indicator announcing that a phone call came in.

a. Alert mode

b. Call alert

c. Message alert

d. Voice mail alert

18. A sophisticated service provider by a cellular carrier that automaticallytransfers an incoming cellular call to another phone number if the cellularsubscribing is unable to answer.

a. Call forwarding

b. Call transferc. Call waiting

d. No-answer transfer

Review Questions


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Review Questions

19. The period of time during which the carriers offer discounted airtimecharges, usually available after 10 p.m. And before 6 a.m., on weekendsand holidays.

a. Night time

b. Lean time

c. Off-peak

d. Peak

20. The standard cellular antenna for a car which prefers to the spring-likesection in the lower third of the antenna known as a phasing coil.

a. Pigtail antenna

b. Omnidirectional antennac. Whip antenna

d. Flexible antenna

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21. The type of cellular phone which is installed in a car or truck. This unit isattached to the vehicle, draws its power from the vehicles battery and has

an external antenna.

a. Mobile or car phone

b. Portable

c. Electronic phone

d. Enhanced cellular phone

22. A protected database that holds a copy of the secret key stored in each

subscribers SIM carda. HLR

b. VLR

c. AuC

d. EIR

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23. The time which a cellular subscriber uses a carriers service charge perunit time of call

a. Talk time

b. Air time

c. Stand-by time

d. Hands off time

24. The subscribers Identity Module (SIM) Card for GSM contains a/n ____

number that identifies the user to the network along with other user and

security information.a. IMEI

b. IMSI

c. ESN

d. MIN


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27. The database for good and known IMEIsa. White

b. Black

c. Grey

d. Red

28. A means of increasing the capacity of a cellular system by subdividing cells

into two or more smaller cells.


b. Cell allocationc. Channel splitting

d. Cell splitting

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29. A database used for management of mobile subscriber.a. HLR

b. VLR

c. MSC

d. EIR

30. The following are the supervisory audio tones used in cellular phones

except

a. 5970 Hz

b. 6000 Hzc. 6030 Hz

d. 3925 Hz

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31. A special signal tone that is transmitted to the cell site to free the voicechanne; when the mobile terminates a cell.

a. 10 KHz

b. 20 KHz

c. 30 KHz

d. 25 KHz

32. In the CDMA cellular technology, the signal meant for a given user is

tagged with a distinctive ________ pattern that only the users receiver

can recognize.a. PIN Code

b.PN Code

c. SIM Code

d. IMSI


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35. A GSM security measure which is designed to prevent eavesdropping ofuser data on the radio path

a. IMSI

b. TMSI

c. IMEI

d. MSRN

36. The uplink frequency range for GSM900

a. 935 960 MHz

b. 890 915 MHzc. 935 960 MHz

d. 890 915 MHz

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39. This is the Nordic analogue mobile radio telephone system originally usedin Scandinavia

a. NMT

b. GSM

c. PCN

d. PCS

40. It is a one-way wireless messaging allows continues accessibility to

someone away from the wired communications network.

a. Pagingb. Trunked radio

c. Cellular telephony

d. Text messaging


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43. What is the meaning of AMPS, which is the standard for analog cellulartelephones?

a. Advanced Mobile Phone Service

b. Automatic Mobile Phone System

c. Analog Mobile Passband System

d. Amplitude Mixing Phone Standard

44. A central computer that connects a cellular phone call to the public

telephone network. It controls the entire systems operation, including

monitoring calls, billing and handofs.

a. Personal Communication Service

b. Wide Area Network Computer

c. Mobile Telephone Switching Office

d. International Standards Organization

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45. A phone that operates on both analog and digital networksa. dual system

b. coupled system

c. pair-mode phone

d. dual-mode phone

46. The geographic area served by a single low-power transmitter/receiver. It

categorizes a cellular systems service area.

a. channel

b. service areac. site

d. cell

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47. Radio frequencies assigned to one channel in a cellular system are limitedto boundaries of a single cell because of their low power. The carrier is

free to use the frequencies again in other cells in the system without

causing any interference. What do you call this method?

a. Frequency assignment

b. Channel utilizationc. Frequency Re-use

d. Optimum Frequency assignment

48. What is the meaning of DSS?

a. Digital Service System

b. Dynamic Service System

c. Data Signal Standard

d. Direct Sequence Spread Spectrum

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49. Cellular systems are designed so that a phone call can be initiated whiledriving in one cell and continued no matter how many cells are driven

through. What is the method of transferring to a new call which is

designed to be transparent to the cellular phone user?

a. Call Transferring

b. Call monitoringc. Call forwarding

d. Handoff

50. What is the meaning of TDMA?

a. Time Data Multiple Access

b. Telephone Data Multiple Access

c. Time Division Multiple Access

d. Telecommunications Digital Data Access

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51. The means of increasing the capacity of a cellular system by subdividing orsplitting cells into two or more smaller cells.


b. Cell allocation

c. Channel splitting

d. Cell splitting

52. This is known as SIM card which contains the subscribers phone number

and billing information as well as memory to store phone numbers.

a. Security Identification Numberb. subscriber Identification Memory

c. Subscriber Identity Module

d. Security Information Module

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53. This is automatically transmitted to the base station every time a cellularcall is placed so the Mobile Switching Center can check the validity of the

call, that the phone has not been reported stolen, that the users monthly

bill has been paid before permitting the call to go through. Each cellular

phone is assigned with this number.

a. Electronic Serial Numberb. Enhanced Series Number

c. Electronic Support Number

d. Electronic Series Number

54. Using a cellular phone outside your home service area.

a. Long Distance Communication

b. Roaming

c. Global communications

d. Jamming

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55. GPRS stands fora. General Packet Radio Service

b. Generic Protocol Radio Service

c. General Protocol for Radio Service

d. Gateway Procedure for Radio Service

56. What is the meaning of GSM, which is the digital standard for Europe?

a. Global Signal Modulation

b. Global System Memory

c. Group Signal for Mobile Services

d. Global System for Mobile Communications

Documents

Cellular Telephony Final