05.103GPPRadio subsystem synchronizationTS
7.1 Frequency source default requirements
The CTS-FP shall use a single frequency source of absolute accuracy better than 5 ppm for both RF frequency generation and clocking the timebase. The same source shall be used for all carriers of the CTS-FP.
7.2 Frequency source for a CTS-FP assisted by a CTS-MS
When the CTS-FP is informed of its Observed Frequency Offset with a BTS, the CTS-FP carrier frequency shall be accurate for one hour to within 2 ppm, or accurate for one hour to within 2 ppm according to the received Observed Frequency Offset.
However, if the Observed Frequency Offset is greater than 2 ppm, the CTS-FP frequency source correction shall have a slope of 0,1 ppm for 936 TDMA frames, i.e. 4,320 seconds.
7.3 Internal CTS-FP carrier timing
The channels of different carriers transmitted by a CTS-FP shall be synchronized together, i.e. controlled by the same set of counters. The timing difference between the different carriers shall be less than 2 symbol periods, measured at the CTS-FP antenna.
7.4 Timeslot length
Optionally, the CTS-FP may use a timeslot length of 157 symbol periods on timeslots with TN = 0 and 4, and 156 symbol periods on timeslots with TN = 1, 2, 3, 5, 6, 7, rather than 156,25 symbol periods on all timeslots.
7.5 Assessment of CTS-MS delay
In order to implement the procedure of control of the CTS-FP service range (specified in 3GPP TS 05.08), the CTS-FP shall monitor the delay of the CTS-MS signal relative to the expected signal from a CTS-MS at zero distance under static channel conditions. The delay of the normal bursts sent by from the CTS-MS shall be assessed in such a way that the assessment error (due to noise and interference) is less than 1/4 symbol period. The conditions under which this requirement must be met shall be 3 dB below the reference sensitivity level or input level for reference performance, whichever applicable, in 3GPP TS 05.56 and 3 dB less carrier to interference ratio than the reference interference ratios in 3GPP TS 05.56.
Annex A (normative):
Additional requirements for pseudo‑synchronization, synchronized handovers and pseudo‑synchronized handovers