B.2 Determination of TN by the CTS-MS when CTSBCH shifting is active

3GPP45.010GSM/EDGE Radio subsystem synchronizationTS

When the CTSBCH shifting procedure is active, the TN can be derived by the CTS-MS according to following procedure:

1) the CTS-MS detects 3 successive CTSBCH-FB, decodes the three associated CTSBCH-SB and stores the two timeslot shifts values between the three successive CTSBCH-FB;

2) the CTS-MS checks that the three FPBI (see 3GPP TS 45.002) extracted from the three CTSBCH-SB are identical and that the three CTSBCH shifting flags all indicate CTSBCH shifting active;

3) the CTS-MS extracts the TNSCN from the FPBI according to the rule defined in 3GPP TS 45.002;

4) the CTS-MS uses timeslot number series couple (TNSTNSCN,0, TNSTNSCN,1) (see 3GPP TS 45.002) and the two stored CTSBCH shift values to determine the three timeslot numbers of the three observed CTSBCH. Due to specific properties of the shifting series, only one mapping is possible.

Annex C (informative):
BTS frequency source stability and E-OTD LMU reporting periods for LCS