EpochTime (EpochTime-r17)
EpochTime-r17 is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.
Definition
The IE EpochTime is used to indicate the epoch time for the NTN assistance information, and it is defined as the starting time of a DL sub-frame, indicated by a SFN and a sub-frame number signaled together with the assistance information. The reference point for EpochTime of the serving or neighbour NTN payload ephemeris and Common TA parameters is the uplink time synchronization reference point of the serving cell when this field is provided in an NTN cell and the gNB when this field is provided in a TN cell. In case of handover or conditional handover, the reference point for EpochTime of the target NTN payload ephemeris and Common TA parameters is the uplink time synchronization reference point of the target cell. In case of handover or conditional handover, EpochTime is based on the timing of the target cell, i.e. the SFN and sub-frame number indicated refers to the SFN and sub-frame of the target cell. Otherwise, EpochTime is used based on the timing of the serving cell, i.e. the SFN and sub-frame number indicated refers to the SFN and sub-frame of the serving cell.
EpochTime-r17 ::= SEQUENCE {
sfn-r17 INTEGER(0..1023),
subFrameNR-r17 INTEGER(0..9)
}Fields (2)
| Field | Description |
|---|---|
| sfn-r17 INTEGER(0..1023) | For serving cell, it indicates the current SFN or the next upcoming SFN after the frame where the message indicating the epochTime is received. For neighbour or target cell when explicit epoch time is present, it indicates the SFN nearest to the frame where the message indicating the epochTime is received. |
| subFrameNR-r17 INTEGER(0..9) |