fn hopping,power control,erlang utilization

8/3/2019 Fn Hopping,Power Control,Erlang Utilization

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FREQUENCY HOPPING, POWERFREQUENCY HOPPING, POWER

CONTROL & BASICS OF RADIOCONTROL & BASICS OF RADIOERLANG UTILIZATIONERLANG UTILIZATION

:R E P A R E D B Y :R E P A R E D B YH A V IN B M E H T AH A V IN B M E H T A&F P L A N N IN G O P T IM IZ A T IO N&F P L A N N IN G O P T IM IZ A T IO N

E N G IN E E RN G IN E E R


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INTRODUCTION TOINTRODUCTION TOFREQUENCY HOPPINGFREQU

ENCY HOPPING


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INTRODUCTION TO FREQUENCYHOPPING.

- ith the ever growing trafficvolume and the limited,re q u e n cy re so u rce fre q u en cy re u se is m o re a n d.ore ag g ressive- ,herefore the problem of how to reduce frequency.n te rfe re n ce b e co m e s m o re a n d m o re re m a rk ab le- -he essence of anti interference is to fullyutilizethe, , .u rre n t sp e ctru m tim e d o m a in a n d sp a ce re so u rce s,h e k ey m e a su re s in clu d e fre q u e n cy h o p p in g( ) , .isco n tin u o u s tra n sm issio n D T X a n d p o w e r co n tro l- SM radio interface uses slow frequency hopping( ) .FH technology The difference between slowre q u e n cy h o p p in g a n d fa st fre q u e n cy h o p p in g is th a th e fre q u e n c y o f la tte r ch a n g e s fa ste r th a n fre q u e n c y. ,o d u la tio n In G S M th e fre q u e n cy re m a in s th e sa m e. ,u rin g b u rst tra n sm issio n T h e re fo re G S M fre q u e n cy

.o p p in g b e lo n g s to slo w fre q u e n cy h o p p in g


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FREQUENCY SPECTRUM & ARFCNCALCULATIONS

- . , . ,V A ILA B LE F R EQ U E N C Y S P E C T R U M 4 4 6 2. , . , , . , . , . , . , . .2 7 8 8 8 2 9 2 1 0 2 1 1 2 1 2 2 M H Z-- .U P P O S E W E H A V E 4 4 M H Z S P E C T R U M.V A ILA B LE A N D D C S 1 8 0 0 B A N D-- .E K N O W G S M C H A N N E L B W IS 2 0 0 K H Z-- . =H E R E F O R E N O O F A V A ILA B LE A R F C N S. / =4 M 2 0 0 K 2 2-- O R T H IS PA R T IC U L A R S P E C T R U M W E U S E 1 2& &R F C N F O R B C C H 9 F O R T C H 1 W ILL B ES E D A S G U A R D B A N D F O R S E P E R A T IO N O FC C H A N D T C H A R F C N-- ( .A LC U LA T E C A R R IE R F R E Q F R O M A R F C N E G)O R 1 8 0 0 B A N D- = + * -u l n 1 7 1 0 2 0 2 n 5 1 2


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SITE CONFIGURATION IN TERMS OFTRX INSTALLATION

THERE WILL BE 2 TYPES OF TRX BCCH & TCH.

FOR 4.4M SPECTRUM 3+3+2 WILL BE THE BEST CONFIG.

MEANS 8 TRX WILL BE USED PER SITE HAVING 3SECTORS

OUT OF WHICH 1 TRX OF EACH SEC WIL BE OCCUPIED ASBCCH & REST ARE TCH.

HENCE 3 BCCH & 5 TCH.

WE HAVE ONLY 9 TCH & TO AVOID ADJUSCENT TCHINTERFERNCE WE WILL USE THIS CONFIGURATION SOWE CAN OCCUPY MAX 5 TCH/SITE.

IN WORST CASE IT CAN BE EXPANDED TO 4+4+4CONFIGURATION IF ADJUSCENCIES ARE AVOIDED &WHERE TRAFFIC IS OVER UTILIZED BUT THIS IS NOTAT ALL RECOMMENDED FOR PROPERLY DESIGNED N/W


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FREQUENCY HOPPINGPARAMETER

GSM defines the following set of parameters:

Mobile Allocation (MA): Set of frequencies the mobile isallowed to hop over. Maximum of 63 frequencies can bedefined in the MA list.

Hopping Sequence Number (HSN): Determines the hoppingorder used in the cell. It is possible to assign 64 differentHSNs. Setting HSN = 0 provides cyclic hopping sequence andHSN = 1 to 63 provide various pseudo-random hopping

sequences.

Mobile Allocation Index Offset (MAIO): Determines inside thehopping sequence, which frequency the mobile starts dotransmit on. The value of MAIO ranges between 0 to (N-1)where N is the number of frequencies defined in the MA list.Presently MAIO is set on per carrier basis.


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FREQUENCY HOPPING TECHNIQUE

. B A S E B A N D: -H


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2. RF OR SYNTHESIZER FH:-


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In the baseband frequency hopping the TRXs operate atfixed frequencies. Frequency hopping is generated byswitching consecutive bursts in each time slot throughdifferent TRXs according to the assigned hopping sequence.The number of frequencies to hop over is determined by the

number of TRXs. Because the first time slot of the BCCH TRXis not allowed to hop, it must be excluded from the hoppingsequence. This leads to three different hopping groups. Thefirst group doesnt hop and it includes only the BCCH timeslot. The second group consists of the first time slots of thenon-BCCH TRXs. The third group includes time slots onethrough seven from every TRX.

In the synthesised frequency hopping all the TRXs exceptthe BCCH TRX change their frequency for every TDMA frameaccording to the hopping sequence. Thus the BCCH TRXdoesnt hop. The number of frequencies to hop over islimited to 63, which is the maximum number of frequenciesin the Mobile Allocation (MA) list

The biggest limitation in baseband hopping is that the numberof the hopping frequencies is the same as the number ofTRXs. In synthesised hopping the number of the hoppingfrequencies can be anything between the number ofhopping TRXs and 63. However in synthesised hopping theBCCH TRX is left completely out of the hopping sequence.The problem for baseband hopping is that if one TRX boardfails, the corres ondin code word will be lost, thus affectin


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INTRODUCTION TO POWERINTRODUCTION TO POWER

CONTROLCONTROL


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INTRODUCTION TO POWERCONTROL

/ .IS O N E O F T H E M ET H O D O F R ED U C IN G N W IN TE R FER E N C E IN G SM S YS TE M IT, &U C E S Y S T E M IN T E R F E R E N C E IM P R O V E S S P E C T R U M U T IL IZ A T IO N IN C R E A S E

.TE R Y LIFE O F M S

WER CONTROL MEANS TO CHANGE THE x , , .P O W E R O F M S B T S O R B O T H&E N E V E R R x LE V R x Q U A L O F PE E R E N D IS G O O D T H E N T x PO W E R C A N B E

U C E D T O R E D U C E T H E IN T E R F E R E N C E T O T H E O T H E R C A L LS IN G S M

&O N C A N B E U S E D IN U L D L R E S P E C T IV E LY

O N R A N G E F O R U L M S IS 2 0 d b m to 3 3 d b m B A S E D O N P O W E R C L A S S O F M S A S.S C R IB E D IN N E X T S LID E


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. .A S S E S O F M S W R T P O W E R


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- MOST MSS GENERALLY BELONGS TO CLASS 4 (IN CASE OF GSM900) & BELONGS TO CLASS 5 (INCASE OF GSM 1800 BAND)

- AND HENCE MAX Tx POWER OF CLASS 4 MS IS 33dbm & 29 dbmIN CASE OF CLASS 5

- EACH STEP CAN CHANGE 2 dbm POWER AT THE TIME

- I.E 33dbm CAN BE STEP DOWN TO 31,29,27 dbm RESPECTIVELY

- THE DL (BTS-> MS) POWER CONTROL REANGE IS DECIDED BYEQUIPMENT MANUFACTURER.

-

- THERE ARE 2 TYPES OF POWER CONTROL AS FOLLOWED,

- 1. MS POWER CONTROL 2. BTS POWER CONTROL LET US DISCUSS EACH IN BRIEF.

--


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MS POWER CONTROL The power control of MS includes two adjustment stages: stable

adjustment stage and initial adjustment stage. Stable adjustment

is the common way to implement power control algorithm. Initial adjustment is used at the beginning of call connection.

When a connection occurs, MS sends signals with nominal power(before receiving power adjustment command, the nominaltransmission power of MS is the maximum transmission power onBCCH of the cell. If MS does not support this power level, it will

adopt other power level most close to this level, such as themaximum power level supported by the classmark of MS inindication message establishment).

Therefore, MS accesses to network through RACH with themaximum power broadcast on BCCH. When MS power is lowerthan this value, it will transmit with its maximum transmission

power. The system specifies that the power level of the firstmessage that MS sends on DCH is also this value. The systemcontrol begins after MS receives the power control command inSACCH information block from SDCCH or TCH.Since BTS can support multi-call at the same time, the Rxlevshould be quickly reduced in the new connection. Otherwise, other

calls supported by this BTS will deteriorate and the calls in othercells will also be affected. The purpose of initial adjustment stage


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The required parameters in uplink power control, the expecteduplink Rxlev, and the uplink received quality can be adjustedaccording to the situation of the cell.

After receiving a certain number of uplink MRs, the system

compares the actual uplink Rxlev and received quality obtained byinterpolation, filtering, and other methods with the expectedvalues and calculate the power level that the MS should beadjusted to through power control algorithm. If the calculatedpower level differs from the output power level of MS and meetscertain limit conditions (such as step limit of power adjustment

and range limit of MS output power), the system will send poweradjustment command. The command of changing MS power and the required time

advance will be sent to MS in the layer 1 header of each downlinkSACCH information block. MS will configure the power level it usesnow in its uplink SACCH information block and send it to BTS in

measurement report. This level is the power level of the last burstin the previous SACCH measurement cycle. When MS receives thepower control information in SACCH information block from DCH, itwill transmit with this power level. One power control messagedoes not make the MS switch to the required level immediately.The maximum change rate of MS power is 2 dB for every 60 ms.

For 12 dB, before MS receives the next power control message, itwill not end as one SACCH measurement cycle takes 480 ms. In


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Execution of power controlcommand

The purpose of uplink power control adjustment is to minimizethe difference between the actual uplink Rxlev and receivedquality and the expected uplink Rxlev and received quality. Thepurpose of interpolation and filtering is to process the lostmeasurement reports and remove temporary nature to ensurethe stability of power control algorithm.The difference between initial adjustment and stableadjustment is that the expected uplink Relev and receivedquality and the length of filter in initial adjustment are different

from that of stable adjustment, and the initial adjustment onlyhas downlink adjustment.


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BTS POWER CONTROL

BTS power control is an optional function. It is similar to MSpower control, but it only uses stable power control algorithm. Therequired parameters are Rxlev threshold (lower limit), and themaximum transmission level can be received (upper limit). TheRelev is divided into 64 levels ranging from 0 to 63. Level 0 is thelowest Rxlev; level 63 is the highest Rxlev.

BTS power control is divided into static power control and

dynamic power control. Dynamic power control is the fine tuningbased on static power control. There are six steps (2 dB/step) ofstatic power control according to Protocol 0505. If the maximumoutput power is 46 dBm (40W), the step 6 is 34 dBm.

Static power control step is defined in the cell distributes list ofdata management system, which specifies the maximum outputpower (suppose this value is Pn) of static power control. For step15 of dynamic power control, the corresponding value range is PndBPn-30dB. When the maximum power control still cannot satisfythe requirement, adjust static power control step to improve themaximum output power of dynamic power control Pn.


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N T R O D U C T IO N T O R A D IO E R L A N GN T R O D U C T IO N T O R A D IO E R L A N GU T IL IZ A T IO NT IL IZ A T IO N


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BASICS OF ERLANGUTILIZATION

.A n E rla n g is a u n it o f te le co m m u n ica tio n s tra ffic m e a su re m e n t

,S trictly spe a kin g a n E rla n g re p re sen ts th e co n tin u o u s u se o f o n e vo ice. ,p a th In p ra ctice it is u se d to d e scrib e th e to ta l tra ffic v o lu m e o f o n e.h o u r

, ,For exa m p le if a g rou p of u ser m ad e 3 0 calls in on e h ou r an d ea ch ca ll,h ad an av erag e calld u ration of 5 m in u tes th en th e n u m b er of E rlan g s

:th is re p re se n ts is w o rke d o u t a s fo llo w s

M in u te s o f tra ffic in th e h o u r = n u m b e r o f ca lls x d u ra tio nM in u te s o f tra ffic in th e h o u r = 3 0 x 5

M in u te s o f tra ffic in th e h o u r = 1 5 0H ou rs o f tra ffic in th e h o u r = /1 5 0 6 0H ou rs o f tra ffic in th e h o u r = .2 5

Tra ffic fig u re = .2 5 E rla n g s


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E rla n g tra ffic m e a su re m e n ts a re m a d e in o rd e r to h e lpte le co m m u n ica tio n s n e tw o rk d e sig n e rs u n d e rsta n d tra ffic p a tte rn s

.w ith in th e ir vo ice n e tw o rks T h is is e sse n tia l if th e y a re to su cce ssfu llyd e sig n th e ir n e tw ork to p o lo g y a n d e sta b lish th e n e ce ssary tru n k g ro u p

.size s

E rla n g tra ffic m e a su re m e n ts o r e stim a te s ca n b e u sed to w o rk o u t h o w

m a n y lin e s are re q u ire d b e tw ee n a te le p h o n e syste m a n d a ce n tra l o ffice( ), .PSTN exchange lines or between multiple network locations

S e ve ra l tra ffic m o d e ls e x ist w h ich sh a re th e ir n a m e w ith th e E rla n g u n it.o f tra ffic T h e y a re fo rm u la e w h ich ca n b e u sed to e stim a te th e n u m b e r

, (o f lin e s re q u ire d in a n e tw o rk o r to a ce n tra l o ffice P S T N ex ch a n g e). ,lin e s A fo rm u la a lso e x ists to m o d e l q u e u in g situ a tio n s a n d le n d s itse lf

.w e ll to e stim a tin g th e a g e n t sta ffin g re q u ire m e n ts o f ca ll ce n te rs

.T h e m a in E rla n g tra ffic m o d e l a re liste d b e lo w in th e N e x t slid e


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rla n g B,T h is is th e m o st co m m o n ly u sed tra ffic m o d e l a n d is u sed to w o rk o u t

( )h o w m a n y lin e s are re q u ire d if th e tra ffic fig u re in E rla n g s d u rin g th e

.b u siest h ou r is kn ow n T h e m od e la ssu m es th at allb locke d calls are.im m e d ia te ly cle a re d

x te n d e d E rla n g B,T h is m o d e l is sim ila r to E rla n g B b u t ta ke s in to a cco u n t th a t a

p e rce n ta g e o f ca lls a re im m e d ia te ly re p re sen te d to th e syste m if th e y( ).en cou n ter b lockin g a b u sy sig n al Th e retry p ercen tag e can b e.sp e cifie d

rla n g C

T h is m o d e l a ssu m e s th a t a ll b lo cke d ca lls sta y in th e syste m u n til th e y.can b e h an d led Th is m o d el can b e a p p lied to th e d esig n of callcen ter, ,sta ffin g a rra n g e m e n ts w h e re if ca lls ca n n o t b e im m e d ia te ly a n sw ere d

.the y en ter a qu eu e


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TRAFFIC CALCULATION IN GSM (IN TERMS OFERLANGS):-

X A M P L E O F S IT E: -O N F IG U R A T IO N


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E E N F R O M S E C T O R C O N F IG U R A T IO N C A L C U L A T IO N S C A N B E D O N E INL O W IN G W A Y S

. =O TA L N O O F T IM E S LO T S 2 4

. =O TA L N O O F T S H A V IN G T C H 1 9

. =O TA L N O O F T S H A V IN G S D C C H 2( % . . ) = .D E A L T R A F F IC F O R T C H IN C LU D IN G 2 O F G O S 1 2 3 3 2 9 E R L

( . % . . )= .D E A L T R A F F IC F O R S D C C H IN C LU D IN G 0 5 O F G O S 0 1 0 5 4E R LH E A B O V E T R A FF IC C A N B E C A LC U LA T E D U S IN G E R LA N G B TA B LE

R E R LA N G C A LC U L A T O R A S A T TA C H E D

D:\nsn docs\

softwares\erlb.exe


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IN GENERAL N/W RADIO CONGIURATION AN ACTUALACHIEVED ERLANG UTILIZATION CAN BE CALCULATED INFOLLOWING WAY,

TOTAL UTILIZED TRAFFIC(IN ERLANGS) = SUM OF(FR+HR+AMRFR+AMRHR)

WHERE, FR- FULL RATE TRAFFIC HR- HALF RATE TRAFFIC AMR FR- ADAPTIVE MODULATION RATE FULL RATE

TRAFFIC AMR HR- ADAPTIVE MODULATION RATE HALF RATE

TRAFFIC


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IN LIVE NETWORK A TRAFFIC CAN BE MEASURED IN TERMS OF NBH & BBH.

NBH:- NETWORKS BUSIEST HOUR NBH TRAFFIC IS GENERALLY MONITORED ON NETWORK LEVEL. IT IS THE THE

BUSIEST HOUR FROM 24 HRS WHEN THERE WAS HIGHEST TRAFFIC UTILIZATION ISFOUND IN TERMS OF ERLANG UTILIZATION IN THE NETWORK.

NBH IS COMMON FOR WHOLE N/W.

BBH:- BOUNCING BUSY HOUR BBH TRAFFIC IS GENERALLY MONITORED ON INDIVIDUAL CELL LEVEL. IT IS THE THE

BUSIEST HOUR FROM 24 HRS WHEN THERE WAS HIGHEST TRAFFIC UTILIZATION ISFOUND FOR PARTICULAR CELL IN TERMS OF ERLANG UTILIZATION IN THE NETWORK.

BBH CAN BE DIFFERENT FOR INDIVIDUAL CELLS IN LIVE N/W.

FOR KPI OPTIMIZATION POINTOF VIEW BBH KPI DUMP IS GENERALLY USED.

FOR N/W POINT OF VIEW NBH ERLANG IS IMPORTANT.

ONE OF THE IMPORTANT PARAMETER CALLED Merl/sub IS ALSO BEEN CALCULATED IN

N/W .

Merl/sub= (TOTAL NBH TRAFFIC*1000)/ATTACHED VLR SUBSCRIBER)

IDEAL VALUE FOR MERL/SUB IS MIN .30 AND ABOVE WHICH IS KNOWN TO BEGOOD IN NETWORK.


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THANK YOU!!!!!!THANK YOU!!!!!!

fn hopping,power control,erlang utilization

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