c04 wcdma rno paging procedure

8/10/2019 C04 WCDMA RNO Paging Procedure

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WCDMA RNO Paging Procedure


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Review

Paging is one of the most important procedures in

WCDMA.

Paging is critical factor associated with the callsetup success rate of the network.


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Objectives

Know the detailed paging

procedure in UMTS

Know how to optimize the

paging procedure

Upon completion of this course,you will be able to:


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Course Contents

Paging initiation

Paging Type

UE DRX procedure

Paging parameters optimization


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Paging initiation

The network will initiate paging in the following three cases:

Mobile terminating call

UTRAN system information update

UE state transitions


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Mobile terminating call

UE NAS UE AS NSS MSC

paging

AUTHENTICATION REQUEST

AUTHENTICATION RESPONSE

RR_SECURITY_CONTROL_REQ

(IK CK)

security mode control

SETUP

CALL CONFIRM

ALERT

CONNECT

CONNECT ACKNOWLEDGE

RAB setup procedure

paging

RR_EST_REQ (PAGING RESPONSE)

RR_PAING_IND

INITIAL_DIRECT_TRANSFER

(PAGING RESPONSE)

RANAPRANAP

RRC setup procedure


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UTRAN system information update

When cell system information changed, paging type 1 is used

to inform mobile to read the updated system information. It is

special for the mobile in IDLE mode, CELL PCH and URA

PCH .

UE RNCNodeB

Cell system information changed

RRC

RRC

RRC

System information update request

RRCPaging type 1

RRC

RRC System information update response


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UE state transitions

Establish RRCConnection

Release RRCConnection

UTRA RRC Connected Mode

UTRA:Inter-RAT

Handover

GSM:Handover

Establish RRCConnection

Release RRCConnection

URA_PCH CELL_PCH

GSM

ConnectedMode

Establish RRConnection

Release RRConnection

Idle Mode

Camping on a UTRAN cell1 Camping on a GSM / GPRS cell1

GPRS Packet Idle Mode1

GPRSPacket

Transfer

Mode

Initiation of

emporarylock flow

Release of

emporarylock flow

Cell reselection

CELL_DCH

out ofservice

inservice

CELL_FACH

out ofservice

inservice

out ofservice

inservice

When UTRAN wants mobile to change its state from CELL PCH or

URA PCH to CELL FACH, UTRAN will send paging type 1 to

mobile.


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Course Contents

Paging initiation

Paging Type

UE DRX procedure



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Paging type 1

When receiving paging from core network, UTRAN decides

the paging type.

When mobile in IDLE mode, CELL PCH and URA PCH,

UTRAN will send paging type 1 on PCCH.

UE Node B

1.1

Node B

2.1

RNC

1

RNC

2

CN

RANAPRANAP1. Paging

2. PCCH: Paging Type 1

RANAP RANAP1. Paging

3. PCCH: Paging Type 1


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Paging type 2

UE Serving

RNC

CN

RRCRRC2. DCCH: Paging Type 2

RANAP RANAP1. Paging

Paging type 2 for a UE in RRC Connected Mode (CELL_DCH

and CELL_FACH states) on DCCH.


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Course Contents

Paging initiation

Paging Type

UE DRX procedure



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DRX

The UE may use Discontinuous Reception (DRX) in order to reduce power

consumption. When DRX is used the UE needs only to monitor one Page

Indicator, PI, in one Paging Occasion per DRX cycle.

In FDD mode, DRX cycle length = 2^k, k is DRX cycle length coefficient.

The UE shall store each CN domain specific DRX cycle length for each CN

domain the UE is attached to and use the shortest of those DRX cycle

lengths.

The CS CNspecific DRX cycle length coefficient shall be updated locally in

the UE using information given in system information.

The PS CNspecific DRX cycle length coefficient shall be updated after the

negotiation between the UE and PS CN by NAS procedure.


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Paging Occasion

0

2^K-1

0 4095

P I P I P I P I

0 1 q NP-1

one pagingoccasion

Paging Occasion = {(IMSI div K) mod (DRX cycle length div PBP)}

* PBP + n * DRX cycle length + Frame Offset, Where n = 0,1,2 as long asSFN is below its maximum value. K is the number of SCCPCH bears the PCH.

In FDD mode, Paging Occasion = IMSI mod 2K + n*2K


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Paging Indicator Channel (PICH)

b1b0

288 bits for paging indication12 bits (transmission

off

One radio frame (10 ms)

b287 b288 b299

One PICH radio frame of length 10 ms consists of 300 bits (b0, b1, , b299). Of

these, 288 bits (b0, b1, , b287) are used to carry paging indicators.

In each PICH frame, Np paging indicators {P0, , PNp-1} are transmitted, where

Np=18, 36, 72, or 144.

The PI calculated by higher layers for use for a certain UE, is associated to the

paging indicator Pq. PI = DRX index mod NP= (IMSI div 8192) mod NP

If a paging indicator in a certain frame is set to "1" it is an indication that UEs

associated with this paging indicator and PI should read the corresponding frame of

the associated S-CCPCH.

NpNpSFNSFNSFNSFNPIq mod144144mod512/64/8/18


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Mapping of paging indicators Pq to PICH bits

Number of paging

indicators per frame (Np)

Pq= 1 Pq= 0

Np=18 {b16q, , b16q+15} = {1,

1,, 1}

{b16q, , b16q+15} = {0,

0,, 0}

Np=36 {b8q, , b8q+7} = {1, 1,,

1}

{b8q, , b8q+7} = {0, 0,,

0}

Np=72 {b4q, , b4q+3} = {1, 1,,

1}

{b4q, , b4q+3} = {0, 0,,

0}

Np=144 {b2q

, b2q+1

} = {1, 1} {b2q

, b2q+1

} = {0, 0}


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Random access procedure

The PICH timing is PICH = 7680 chips prior to its corresponding

S-CCPCH frame timing, i.e. the timing of the S-CCPCH carrying

the PCH transport channel with the corresponding paging

information

PICH

Associated S-CCPCH frame

PICH frame containing paging indicator


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Course Contents

Paging initiation

Paging Type

UE DRX procedure



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Paging Cycle Coefficient

In the idle mode, the UE can receive the paging indication with DRX to reducethe power consumption. At this time, the UE needs to detect only one paging

indication in a paging occasion within a DRX cycle. The DRX cycle length of

UTRAN domain is obtained by substituting this parameter into the formula

DRXcycle = 2KPBP frames. Where, K is [the paging cycle coefficient],

and PBP is the paging block cycle coefficient (In the FDD mode, PBP = 1).

Influence on the network performance: If this parameter is set too small,

the UE will detect the paging channel frequently, and thus the battery is

consumed fast; if it is set too big, the UE will react very slowly on the paging,

it will also occur that the system repeats the UE paging, and the downlink

interference will be increased.


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Np

Np is the number of paging indicators per frame. The value

range of this parameter is 18, 36, 72, or 144.

Influence on the network performance:

PI = DRX index mod NP= (IMSI div 8192) mod N

P.

All of the IMSIs is divided into Np groups. If this parameter is

set too small, for one IMSI, the paged probability of this IMSI

will increase and it will consume too much power. If this

parameter is set too big, the paged probability will decrease.

The bit number of each PI decrease too, and it requests high

demodulation performance for UE.


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Summary

Paging initiation occasions: Mobile terminating call, UTRAN

system information update, UE state transitions.

Paging type: paging type 1 and paging type 2.

UE DRX procedure: UE may monitor the corresponding PI inevery paging cycle.

Parameters optimization: Paging Cycle Coefficient and Np.


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c04 wcdma rno paging procedure

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