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DESIGN, IMPLEMENTATION AND OPTIMISATION OFCDMA NETWORKS (RF PLANNING)
DEEPRA BHATTACHERJEE, ABHRA MAZUMDAR, EEE 06Project Guide: Ashok R !" s# $%, EEE De&t'
CDMA stands for "Code Division Multiple Access." It is a form of spread-
spectrum, an advanced digital wireless transmission technique. Instead of using
frequencies or time slots, as do traditional technologies, it uses mathematical codes to
transmit and distinguish between multiple wireless conversations. Its bandwidth is much
wider than that required for simple point-to-point communications at the same data rate
because it uses noise-li e carrier waves to spread the information contained in a signal ofinterest over a much greater bandwidth. !owever, because the conversations ta ing place
are distinguished b digital codes, man users can share the same bandwidth
simultaneousl .
#$ %&A''I'( deals with the air interface between the )A*+ #A'*C+I +#
* A I ' / the M )I&+ 0'I . It also involves designing and optimi1ing the networ
in order to provide a high qualit service to customers.
he ob2ective of the pro2ect is to plan, design / optimi1e a cell site at BA(GARPET'
he main purpose of the planning is fewer base stations per networ , greater s stem
efficienc and capacit , improved voice qualit and a reduction or elimination of drop
outs and multi path problems. All of which result in improved services and greatl
reduced networ cost.
THE VARIOUS STAGES INVOLVED IN CDMA RFPLANNING & OPTIMISATION
3. MAR)ET *UR+E : Depending on the mar eting feedbac , a thorough surve is
conducted to define the area of coverage / potential candidate sites are listed out. he
mar et surve also gives the area morpholog -terrain and clutter information. he
purpose of the mar et anal sis is to collect all the information from the mar et that
affects the design of the #$ 'etwor . he following information is gathered4
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a5 Classification of various t pes of morphologies in the area
b5 Ma2or points of interest
he e6act locations of the important places of the town were recorded using a (& )A&
% *I I 'I'( *7* +M 8I as shown below.
- titude -o!"itude-oc tio!39.:;;.3
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$I(0#+ 3. )A'(A#%+ %# % *+D *I + C +#A(+ CA&C0&A I ' 0*I'(%&A'+ +After Clutter classification is done, the location of the cell site is derived based on the
information gathered. )ased on the information collected, design process is carried out
as shown4
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$I(0#+ 9. D+*I(' %# C+** B%#+ A'A&7*I*5
he penetration median losses, standard deviations, and fade margins calculated on this
basis below are ta en directl to the lin budgets to be used in later cell planning.
C/MP/* TE PR/BAB - T /4 *ER+ CECA&C0&A I'( #+ 0I#+D $AD+ MA#(I'
+' I# 'M+'7%+
B M #%! & (7E5
)0I&DI'(%+'+ #A I '
0 D # C M% *I + A&
M+DIA'& **,D)
* D.D+ .F,D)
* D.D+ .F, D)
A#+AA AI&I)I&I 7
A#(+ ,G
$AD+MA#(I'BD)5
D+'*+ 0#)A')&D(.
9= ; ; :=GH>?G +D(+ >.?G +D(+ >.?G +D(+ >.?G +D(+ >.
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$I(0#+ K. ! #IL ' A& %&
$I(0#+ @. +# ICA& %&
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$I(0#+ ?4 )A'(A#%+ A'A& ( %#+DIC I ' B #IA&5
CDMA re5erse i!k ! %sis: he + reverse lin anal sis computes the probabilit
that a mobile user , with the abilit to transmit at the ma6 +#% specified b ou, is able
to close the reverse lin . #everse lin closure is computed as the probabilit of receiving
a mobile unit s signal at the serving siteBs5
ith sufficient mobile unit traffic channelBreverse lin target5 +bH't for acceptable call
qualit . he reverse lin anal sis incorporates the statistical nature of the processes and
computes the probabilit of closing the lin for each handoff t pe. Closing the reverse lin in no handoff is predicted in terms of a single
probabilit . hile the various softE handoff configurations are computed in terms of
2oint probabilities that at least one of the contributing entities will receive adequate
signal.
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CDMA 4or# rd i!k ! %sis 4 his anal sis verifies that the specified threshold
B NADD or ND# % specified for each cellHsector5 for pilot channel coverage has been
met or e6ceeded before a cellHsector is considered to be a valid contributor. he hand-off
contributors are based on the strongest pilot signals at each bin.
7' R4 MP-EME(TAT /(: nce the proposed cell site has been finali1ed, #$
implementation team swings into action wherein the proposed cell site is ph sicall
implemented.
$I(0#+
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8' (ET1/R) PER4/RMA(CE M/( T/R (G: nce the base station is set up, its
performance is continuousl monitored. his process is called drive testing. he tool is
called +M* I' +* I(A # from +#IC** '. he drive test s stem is placed in a
vehicle / driven throughout the coverage area of potential site. It actuall gives a
subscriber s point of view of the networ . It can evaluate call - processing operations,
perform call processing functions and signal qualit of received base station signal.
Dri5e test 9or $ode c i r tio!: A significant number of t pical sites are evaluated
using the test transmitter / receiver to determine signal deca rates and to get a fairl
accurate understanding of the effects of t pical clutter in the area. ests are also
conducted to evaluate the additional attenuation which the signal suffers during
penetration of t pical buildings and vehicles. he focus is on developing models
generall applicable to the area, not on performance of specific individual sites.
Dri5e test 9or site e5 u tio!: Although propagation models for an area alread have
been refined coverage of a particular site is so critical, or its environment so variable due
to urban clutter that it is essential to actuall measure the coverage and interference it will
produce. he focus is on this specific site.
CDMA Per9or$ !ce !dic tors:
!dic tor ; o O hat does it meanP
h can t we 2ust use the handset s received power level to guide handoffsP
)ecause it is a simple total #$ power measurement, the total of all sectors
reaching the mobile. e need a wa to measure the signal strength of each sector
individuall , / we must be able to measure it quic l / simpl . he solution is to use
each sector s pilot B alsh =5 as a test signal to guide handoffs.
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At the mobile, if the pilot of a certain sector is ver strong / clean, that means we
also should be able to hear a traffic channel on that sector, so handoff would be a good
idea.
If the pilot of a certain sector is wea , then we probabl won t be able to get much
benefit from using a traffic channel on that sector.
6' P/*T A(A- * * 4 he drive test data is loaded into a post anal sis tool. It assesses
the end-to-end performance of the networ infrastructure. It can be used to anal 1e the
benchmar drive data to compare the performance of their own networ with those of
competitors. & uses +M* D+*8CA as the post anal sis tool. e get the following
parameters4 +cHIo, 6 power, #6 power and $+#.
$I(0#+ >4 CDMA %A#AM+ +#* $# M +M* I' +* I(A #
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$I(0#+ ;4 +CHI %&
Starting optimization on a new systemR4 co5er "e co!tro
r to contain each sectors coverage, avoiding gross spillover into other
sectors.
Too s 4 %' plots, !andoff state plots, mobile 6 plots.
(ei"h or ist tu!i!"
r to groom each sector s neighbor to onl those necessar but be alert to
special needs due to topograph / traffic.ools4 %*MM data from mobilesQ propagation prediction.
*e rch #i!do# setti!"s
$ind best settings for *#C!N I'NA,N',N#
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+speciall optimi1e *#C!N I'NA per sector using collected finger
separation dataQ has ma2or impact on pilot search speed.
ACCE** 9 i ures, dro&&ed c ! %sis
$inall , iterative corrections until within numeric goals.
35 %erformance monitoringHgrowth management
95 )enchmar e6isting performance
K5 Identif problem cells / clusters
@5 &oo for signs of overload
?5 raffic trending / pro2ection
hese steps must be continuousl applied to guide needed growth.
CONCLUSION he construction of the cell site at )angarpet was completed. he site became full
operational in the first wee of APR -, .006' he pro2ect wor is carried out for A A
elecom.
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PARTIAL DISCHARGE MEASUREMENT FOR HIGHVOLTAGE CA LE TERMINATIONS
A#0' 80MA#, )!A#A .(, *0MI 80MA#, +++ =