3 Timebase counters

3GPP45.010GSM/EDGE Radio subsystem synchronizationTS

3.1 Timing state of the signals

The timing state of the signals transmitted by a BTS (for normal symbol period), a MS (for normal symbol period), a CTS-FP, or an Compact BTS and MS is defined by the following counters:

– Quarter symbol number QN (0 ‑ 624)

– Symbol number BN (0 ‑ 156);

– Timeslot number TN (0 ‑ 7);

– TDMA frame number FN (0 to (26 x 51 x 2048) ‑ 1 = 2715647); or

– for a non attached CTS-MS, TDMA frame number modulo 52 T4 (0 – 51); or

– for Compact, TDMA frame number FN (0 to (52 x 51 x 1024) -1 = 2715647).

In CTS, the CTS-MS shall manage different sets of counters for CTS operation and GSM operation.

Alternatively, in case of transmission using reduced symbol period, for a BTS or an MS the following counters have the following ranges:

– Quarter symbol number QN (0-749)

– Symbol number BN (0-187)

3.2 Relationship between counters

The relationship between these counters is as follows:

– QN increments every 12/13 µs for normal symbol period and every 10/13µs for Reduced Symbol Period;

– BN = Integer part of QN/4;

– TN increments whenever QN changes from count 624 to 0 for normal symbol periodand whenever QN changes from count 749 to 0 for reduced symbol period;

– FN increments whenever TN changes from count 7 to 0; or

– for a CTS-MS, T4 increments whenever TN changes from count 7 to 0.