8.14.1 MCCH scheduling implementation

34.123-33GPPPart 3: Abstract test suite (ATS)TSUser Equipment (UE) conformance specification

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The rules for the transmission of MCCH messages are specified in 3GPP TS 34.108 [3], clause 11.1.2. The current clause provides the implementation guidelines.

Figure 8.14.1.1: Segmentation and concatenation of MCCH messages into RLC PDU’s

If required in the test, all ACCESS INFORMATION messages of a modification period are sent via RLC_UM_ACCESSinfo_REQ. Each ACCESS INFORMATION message corresponds to an access information period in an ordered way. The ACCESS INFORMATION is transmitted on the 1^st TTI of the second access information period of the modification period.

All critical MCCH messages of a modification period are sent via RLC_UM_CriticalMCCHMsg_REQ. The sequence of the critical MCCH messages is segmented and concatenated without padding by a UM RLC entity configured specifically for MCCH. RLC_UM_ACCESSinfo_REQ precedes RLC_UM_CriticalMCCHMsg_REQ, or RLC_UM_CriticalMCCHMsg_REQ can be used alone. The scenarios of RLC_UM_ACCESSinfo_REQ used alone or RLC_UM_CriticalMCCHMsg_REQ preceding RLC_UM_ACCESSinfo_REQ are not applied.

The first RLC SN are always allocated consecutively to ACCESS INFORMATION messages, i.e. from n + 0 onwards as necessary. Then an RLC SN block is consecutively allocated to the critical MCCH messages, saying the last used SN = (n +m)MOD 128 in the current modification period. Renew n to (n + m + 1)MOD 128 for the next modification period.

Figure 8.14.1.2: RLC SN allocation in MCCH scheduling

ACCESS INFORMATION messages within a modification period have different RLC SN. The SN = n + 0 is allocated to the 1^st ACCESS INFORMATION message. The critical MCCH messages to be transmitted in the different repetition periods within a modification period have the same RLC SN. RLC SN are incremented across the boundary of two consecutive modification periods without RLC reestablishment. The different RLC SN are allocated to the two consecutive modification periods.

In order to ensure UE can read the first ACCESS INFORMATION message, the message is sent by the TTCN in the second access information period.