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42 NOKIA 2000 BSSPARS9 Jun 00

IDLE MODE OPERATIONContents

1. IDLE Mode tasks overview

2. IDs and ID Codes , Frequencies

3. PLMN selection

4. Cell selection and cell reselection

C1 Algorithm

C2 Algorithm

5. Location Area Management (as in Radio Resource Management)

Location Updates

Time Periodic Location Update

6. IMSI Attach/Detach

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IDLE MODE OPERATION

When the MS is switched ON

When there is no dedicated connection

To camp on the best suitable cell

For MS to receive system info from the NW on DL

For MS to be able to initiate a call whenever needed

For the NW to be able to locate the MS when there is a MT call/SMS

When?

Why?

Why to camp on a specific cell?

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IDLE MODE OPERATIONIdle Mode Tasks

PLMN selection

Cell selection and reselection

Location update

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locationAreaId

ncc (Network Colour Code) 0 7

bcc (BTS Colour Code) 0 7

bsIdentityCode

cell-ID 0 65535

Parameter Value

trainingSequenceCode 0 7

IDLE MODE OPERATIONID's and ID Codes

mcc (Mobile Country Code) 0 999

mnc (Mobile Network Code) 0 99

lac (Location Area Code) 0 65535

Cell Global Identity MCC + MNC + LAC + CI

BTS

BTS

BTS

TRX

BTS

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IDLE MODE OPERATIONBaseStation Identity Code (BSIC)

BSIC is a combination of NCC and BCC

Reported in Measurement Results to BSC

Can be listed in Hex or Decimal

NCC (0...7) BCC (0...7)4 2 U 4 2 U

32 16 8 4 2 U Range

0 0 0 x x x 0 - 7

0 0 1 x x x 8 - 15

0 1 0 x x x 16 - 23

0 1 1 x x x 24 - 31

1 0 0 x x x 32 - 391 0 1 x x x 40 - 47

1 1 0 x x x 48 - 55

1 1 1 x x x 56 - 63

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IDLE MODE OPERATIONBase Station Colour Code

MNC = Operator

MCC = Country e.g Finland

LAC 1 = HelsinkiLAC 2

LAC 3 LAC 4

f1

f2

f3

f1

f1

bcc = 1

bcc = 2

bcc = 3

Neighbour list of f3:

f1f2

...

Location Area Code

BSC

BTSBTSBTS1 2 n

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plmnpermitted 0 ... 7

Parameter Value

NOTE This parameter is confusing. Its not used for network selection. Its used AFTER

a network has been selected so that only measurements from one PLMN are rreported

IDLE MODE OPERATIONPLMN Selection

Two ModesAutomatic

Manual

Three Types of Lists

Preferred

Found

Forbidden

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initialFrequency 1 ... 124 GSM 900

512 885 GSM 1800

512 810 GSM 1900

Parameter Value

bCCHAllocation-ID 1 ... 128 in GSM

bCCHAllocationList 1 ... 124 in GSM ( max. 32 freq. for all bands)

idleStateBCCHAllocation 0 (BCCH list is taken from the adjacent cell)1 ... 128 (number of the BCCH list used)

measurementBCCHAllocation ADJ (BCCH frequency list taken from adj. cell)

IDLE (active MS uses the same list as MS

in IDLE mode)

IDLE MODE OPERATIONFrequencies

TRX

BSC

BTS

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IDLE MODE OPERATIONCell Selection in Idle Mode

Two methods:

a) Normal cell selection

b) Stored list cell selection (opt)

If no suitable cell found with with method b) then a) is tried.

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IDLE MODE OPERATIONSuitable cell to camp on

Cell is in the selected PLMN

Cell is not barred

It is not in a forbidden location area for national roaming

C1 >0

If there is no normal priority cell then low priority cell

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Averaging 3-5 s.Decision 5s.

IDLE MODE OPERATIONCell Selection in Idle Mode- Implementation

Radio CriteriaC1 = (A - Max(B,0))

A = Received Level Average - p1

B = p2 - Maximum RF Output Power of the Mobile Station

p1 = rxLevelAccessMin Min. received level at the MS required for access tothe system

p2 = msTxPowerMaxCCH Max. Tx power level an MS may use whenaccessing the system

rxLevelAccessMin -110 ... -47

msTxPowerMaxCCH 5 43

Parameter Value

BTS

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IDLE MODE OPERATIONCell Selection in Idle Mode, GSM 1800

The powerOffset parameter is used for class 3GSM 1800 MSs (P = 36dBm).

P2 = msTxPowerMaxCCCH + powerOffset

When calculating C1

When accessing the Network

powerOffset 0 = 0 dB1 = 2 dB

2 = 4 dB

3 = 6 dB

Parameter Value

BTS

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IDLE MODE OPERATIONIdle mode Controls

ParameterValue

Access

Parameters

notAllowedAccessClasses 0 ... 9, 11 ... 15

emergencyCallRestricted Yes/No

msMaxDistanceInCallSetup 0 ... 255 BTS

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IDLE MODE OPERATIONCell Re-selection in Idle Mode

Cell re-selection is needed if

Path Loss criterion C1 < 0 for cell camped on ,for more than 5 seconds. There is DL signalling failure

The cell camped on has become barred.

There is a better cell in terms of C2 criterion

A random access attempt is still unsuccessful after maxNumberRetransmission

repetitions.

MS will calculate the C1 and C2 for the serving cell, every 5 sMS will calculate the C1 and C2 for the six best neighbour cells, every 5 s

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cellReselectParamInd Y C2 reselection parameters are broadcast

N C2 reselection parameters are not broadcast

cellReselectOffset 0 ... 126 (dB) 2 dB step

penaltyTime 20 ... 640 (s) 20 s step

temporaryOffset 0 ... 70 (dB) 10 dB step (the value is negative)

Parameter Value

C1 + cellReselectOffset - temporaryOffset*H(penaltyTime-T)

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timepenaltyTime

C

1

cellReselectOffset

cellReselectOffset

C2

C2

temporaryOffset

dB

IDLE MODE OPERATIONCell Re-selection with C2, continues

C2 when penaltyTime = 640

C2 when penaltyTime < 640

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IDLE MODE OPERATIONCell Re-selection

cellReselectHysteresis (0 14 dB)

A = 4 dB

B = 6 dB

C = 8 dB A B C 1 2

1

2

MS Moving

A B C

LA1 LA2

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IDLE MODE OPERATIONCell Re-selection

cellReselectHysteresis (0 14 dB)

cellReselectHysteresisThe nominal LA border

The real LA border

L1

L2

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IDLE MODE OPERATIONCell Barred

Existing Layer

Barred, No

New Microcell Layer

Barred, Yes

Call setup on macro, no SDCCH needed in micro (only BCCH)

GPS-satellite

Measurement SystemcellBarQualify Y cell bar can be overridden

N cell bar can not be overridden

Example

O O O

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timerPeriodicUpdateMS 0.0 ... 25.5 (hours)

allowIMSIAttachDetach Yes/No

Parameter Value

IDLE MODE OPERATIONLocation Update

MS => MSC / VLR

Mobile Station switched ONNo IMSI Attach / Detach

Same Location Area => No Location Update

Different Location Area => Location Update

Change of the Location Area

Location Area under the same MSC / VLR

Location Area under another MSC /VLR => HLR will be updated

Service is rejected (MS unknown in VLR)

Time Periodic (MS -> MSC/VLR)

BTS

4.idle mode

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