rachrootsequence planning.pptx

7/25/2019 RachRootSequence Planning.pptx

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RachRootSequencePlanning

Prepared By-RAJESH KUMAR


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Random access preambletransmission

First step in the random access procedre is thetransmission o! a random access preamble

"ndicates to the e#odeB the presence o! arandom access attempt and to allo$s the

e#odeB to estimate the delay bet$een thee#odeB and the UE

Random access preamble is transmitted onPhysical Random Access %hannel &PRA%H'

"n a (rst step o! the random access procedre)the UE selects one preamble to transmit on thePRA%H


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Preamble se*ence

generation +he preamble consists o! t$o parts,

Preamble se*ence

%yclic pre(

"n each cell) there are ./ preamble se*ences a0ailable

Preamble se*ences are constrcted !rom one or se0eral root1ado2-%h &1%' se*ences) by combining di2erent cyclic

shi!ts o! each root se*ence 3ogical root 1% se*ence inde is broadcasted as part o! the System

"n!ormation

+here are 454 di2erent root 1% se*ences sed !or random accessand each 1% se*ence consists o! N1%6 457 samples

A ne$ parameter is introdced in the crrent release !or the

Random access process,


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rachRootSequencePlanning

"t can be bene(cial to plan rachRootSequencesch thatthe same root se*ences are not sed in neighboring cells

"! the same root se*ences are sed in neighboring cells) andthe PRA%H allocation o0erlaps) this $ill lead to an increased !alsealarm ratio) $here a random access preamble transmitted by aUE in the neighboring cell cold be detected by the e#odeB

+his is mainly a problem $hen the random access load is high

"n cells) $here UEs are tra0ersing $ith high speed) the restrictedset o! root 1% se*ences shold be sed

"t cold be applicable !or cells that co0er rail$ays andhigh$ays

"t is not applicable in USA becase speeds on rail$ays andhigh$ays do not eceed 89: mph &limit !or 8799 MH;'

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700 800 900 10001100120013001400150016001700180019002000210022002300240025002600

Carrier frequency [MHz]

UEspeed[km/h]


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rachRootSequencePlanningRE%? since there is a $rap-arond bet$een

the (rst and last 0ale in the 0ale range'


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rachRootSequence

@R


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rachRootSequence P3A##"#@Process P# planning tool in Planet $ill be sed to generate a P#

plan and then con0ert the P# plan to therachRootSequenceplan

8 Best ser0er layer $ill be generated

> #eighbor list $ill be created by tili;ing best ser0er layer in Planet

5 A P# plan $ith an increment o! ? $ill be generated

@i0es >/ grops) no reser0es

rachRootSequencegroping incldes >4 grops &see slide .'

/ +aCe the (rst >/ grops and replace the P# Plan created in Planet $ith0ales listed on slide .

/ spare grops le!t


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+HA#KS

rachrootsequence planning.pptx

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