20.20 Multiband cell selection and reselection

3GPP51.010-1Mobile Station (MS) conformance specificationPart 1: Conformance specificationTS

20.20.1 Multiband cell selection and reselection / Cell Selection

20.20.1.1 Definition

Multiband cell selection is a process in which a multiband MS, whenever a new PLMN is selected, attempts to find a suitable cell of that PLMN to camp on, irrespective of frequency band. Two methods of searching for a suitable cell are possible, normal cell selection and stored list cell selection. The process ensures that the MS is camped on a cell from which it can reliably decode downlink data and with which it has a high probability of communications on the uplink. Once the MS is camped on a cell, access to the network is allowed.

20.20.1.2 Conformance requirement

1. The MS shall search all RF channels within its bands of operation, take readings of received RF signal level on each RF channel, and calculate the RLA_C for each. The averaging is based on at least five measurement samples per RF carrier spread over 3 to 5 s, the measurement samples from the different RF carriers being spread evenly during this period.

A multi band MS shall search all channels within its bands of operation as specified above. The number of channels searched will be the sum of channels on each band of operation.

3GPP TS 45.008, subclause 6.2.

2. … the MS shall be able to select the correct (fourth strongest) cell and be able to respond to paging on that cell within 30 s of switch on, when the three strongest cells are not suitable. This assumes a valid SIM, with PIN disabled and ideal radio conditions; 3GPP TS 05.08, subclause 6.1.

3. There are various requirements that a cell must satisfy before an MS can perform normal camping on it:

3.1 (i) It should be a cell of the selected PLMN

3.2 (ii) It should not be "barred" (see subclause 3.5.1)

3.3 (iv) The radio path loss between MS and BTS must be below a threshold set by the PLMN operator. This is estimated as shown in subclause 3.6.

3GPP TS 03.22, subclause 3.2.1.

NOTE: Criteria (iii) is not applicable for Cell Selection

4. Initially the MS looks for a cell which satisfies these 4 constraints ("suitable cell") by checking cells in descending order of received signal strength. If a suitable cell is found, the MS camps on it; 3GPP TS 03.22, subclause 3.2.1.

5. The MS shall be able to calculate correctly the path loss criterion parameter C1, used for cell selection and reselection; 3GPP TS 05.08, subclause 6.4.

20.20.1.3 Test purpose

1. To verify that the MS meets conformance requirement 1.

2. To verify that the MS meets conformance requirement 2 in a multiband environment.

3. To verify that:

3.1 The MS does not select a cell of a PLMN which is not the selected PLMN.

3.2 The MS does not select a cell which is "barred".

3.3 The MS does not select a cell with C1 < 0.

4. To verify that the MS selects suitable cells in descending order of received signal strength, irrespective of frequency band.

5. To verify that the MS does not select a cell with C1 < 0.

20.20.1.4 Method of test

20.20.1.4.1 Initial conditions

Parameters changed from the default values in table 20.1.

Parameter

Carrier 1

Carrier 2

Carrier 3

Carrier 4

Carrier 5

Carrier 6

RF Signal Level

(dBmV emf() / dBm)

48 / -65

36 / -77

43 / -70

33 / -80

23 / -90

OFF

CBA

1

0

0

0

0

RXLEV_ACCESS_MIN (dBm)

-90

-69

-90

-88

-98

MNC

See Table 20.1c

See Table 20.1c

MCC

002

MS_TXPWR_MAX_CCH

7

7

7

C1

25

-8

20

8

8

C2

25

-8

20

8

8

Carrier 1, carrier 2 and carrier 4 ARFCNs are chosen in the lower band, carrier 3 and carrier 5 ARFCNs in the higher band.

20.20.1.4.2 Procedure

a) The SS activates the carriers and monitors carriers 2, 4 and 5 for RA requests from the MS.

b) The MS is switched on.

c) The MS is switched off.

d) The SS monitors carriers 1 and 3 for RA requests from the MS.

e) The MS is switched on.

f) The MS is switched off.

g) The SS is reconfigured and sets MCC of carrier 3 to 001 (same as the other carriers).

h) The SS activates the carriers and monitors carriers 3, 4 and 5 for RA requests from the MS.

i) The MS is switched on.

j) The MS is switched off.

k) For multiband MS supporting three or more bands all valid combinations of two bands shall be tested using the steps from a) to j). The valid combinations are indicated in sub-clause 26.11.6 Multiband signalling / Default messages contents.

20.20.1.4.3 Specific PICS statement(s)

– Support for stored list cell selection Yes/No (TSPC_AddInfo_StoredListCellSel)

20.20.1.4.4 PIXIT Statements

20.20.1.5 Test requirements

1) After step b), the first response from the MS shall be on carrier 4 within 33 s. If the MS supports stored list cell selection MS may be also on carrier 5. There shall be no response from the MS on carrier 2.

2) After step e), there shall be no response from the MS on either carrier 1 or carrier 3 within 33 s.

3) After step i), the first response from the MS shall be on carrier 3 within 33 s. If the MS supports stored list cell selection the first response may be also on carrier 4 or carrier 5.

20.20.2 Multiband cell selection and reselection / Cell reselection

20.20.2.1 Definition

While camped on a cell of the selected PLMN the multiband MS may need to select a different cell (irrespective of frequency band used) in order to fulfil the normal service state. This ensures that the MS is camped on a cell from which it can reliably decode downlink data and with which it has a high probability of communications on the uplink.

20.20.2.2 Conformance requirement

1. The list of the 6 strongest non-serving carriers shall be updated at least as often as the duration of the running average defined for measurements on the BCCH allocation and may be updated more frequently; 3GPP TS 05.08, subclause 6.6.1.

2. When the MS recognizes that a new BCCH carrier has become one of the 6 strongest, the BCCH data shall be decoded for the new carrier within 30 s; 3GPP TS 05.08, subclause 6.6.1.

3. The MS shall be able to calculate correctly the path loss criterion parameter C2 used for cell reselection; 3GPP TS 05.08, subclause 6.4.

20.20.2.3 Test purpose

1. To verify that MS meets conformance requirement 1.

2. To verify that MS meets conformance requirement 2.

3. To verify that the MS calculates the C2 parameter correctly when the CELL_RESELECT_OFFSET, and PENALTY_TIME parameters are used to give different priorities to different frequency bands.

20.20.2.4 Method of test

20.20.2.4.1 Initial conditions

Six BCCH carriers are established with the system information contents of table 20.1.

Parameters changed from Default values table 20.1.

Parameter

Carrier 1

Carrier 2

Carrier 3

Carrier 4

Carrier 5

Carrier 6

Carrier 7

RF signal level

(dBmV emf ( )/dBm)

53 / -60

48 / -65

43 / -70

38 / -75

33 / -80

33 / -80

43 / -70

RXLEV_ACCESS_MIN (dBm)

-90

-90

-90

-90

-90

-90

-110

PT

11111

CRO

20 dB

MS_TXPWR_MAX_CCH

7

7

7

C1

30

25

20

15

10

10

40

C2

30

25

20

15

10

10

20

Carrier 1, 2 and 3 ARFCNs are chosen in the lower band, carrier 4, 5, 6 and 7 ARFCNs in the higher band.

The BA(BCCH) list contains only eight ARFCNs and includes those of carriers 1 to 7.

BS_PA_MFRMS is set to 3 during this test.

NOTE: The combination of 8 carriers on the BA list and BS_PA_MFRMS = 3 leads to averaging time of 5 s. Hence 5 s is also the updating time of the list of six strongest neighbour carriers.

20.20.2.4.2 Procedure

a) The SS activates carriers 1 to 6. The MS is not paged on any of the carriers.

b) The MS is switched on.

c) After 60 s, the SS deactivates carrier 4 and activates carrier 7 and pages the MS continuously on carrier 7. The SS monitors carrier 7 for RA requests from the MS.

d) The MS is switched off.

e) The SS is reconfigured and sets PT = 0 and CRO = 0 on carrier 7 (thus increasing C2 to 40 dB).

f) The SS activates carriers 1 to 6. The MS is not paged on any of the carriers.

g) The MS is switched on.

h) After 60 s, the SS deactivates carrier 4 and activates carrier 7 and pages the MS continuously on carrier 7. The SS monitors carrier 7 for RA requests from the MS.

i) 20 s after receiving an RA request on carrier 7 the SS sets PT = 11111 and CRO = 20 dB on carrier 7 (thus decreasing C2 to 20dB), stops paging on carrier 7, and pages the MS continuously on carrier 1. The SS monitors carrier 1 for RA requests from the MS.

j) The MS is switched off.

k) For multiband MS supporting three or more bands all valid combinations of two bands shall be tested using the steps from a) to j). The valid combinations are indicated in sub-clause 26.11.6 Multiband signalling / Default messages contents.

20.20.2.5 Test requirements

1) After step c) there shall be no response from the MS on carrier 7 within 55 s of activating carrier 7.

2) After step h) the MS shall access on carrier 7 within 55 s of activating carrier 7.

NOTE: 5,5 s to notice new strongest carrier in top 6 (because the updating time for six strongest is 5 s (+10 %)), 33 s to read BCCH, 15 s for reselection, since the MS has already performed the running average on the new strongest carrier, allow 55 s.

3) After step i) the MS shall access on carrier 1 within 55 s of setting PT and CRO on carrier 7.