LTETimeAadvance学习笔记.docVIP

TS36.211 8 Timing 8.1 Uplink-downlink frame timing Transmission of the uplink radio frame number from the UE shall start seconds before the start of the corresponding downlink radio frame at the UE, where 0 ? NTA ? 20512, for frame structure type 1 and for frame structure type 2. Note that not all slots in a radio frame may be transmitted. One example hereof is TDD, where only a subset of the slots in a radio frame is transmitted. Downlink radio frame #i Uplink radio frame #i Figure 8.1-1: Uplink-downlink timing relation TS36.213 4.2.3 Transmission timing adjustments Upon reception of a timing advance command, the UE shall adjust its uplink transmission timing for PUCCH/PUSCH/SRS. The timing advance command indicates the change of the uplink timing relative to the current uplink timing as multiples of 16. The start timing of the random access preamble is specified in [3]. In case of random access response, 11-bit timing advance command [8], TA, indicates NTA values by index values of TA = 0, 1, 2, ..., 1282, where an amount of the time alignment is given by NTA = TA ?16. NTA is defined in [3]. In other cases, 6-bit timing advance command [8], TA, indicates adjustment of the current NTA value, NTA,old, to the new NTA value, NTA,new, by index values of TA = 0, 1, 2,..., 63, where NTA,new = NTA,old + (TA ?31)?16. Here, adjustment of NTA value by a positive or a negative amount indicates advancing or delaying the uplink transmission timing by a given amount respectively. For a timing advance command received on subframe n, the corresponding adjustment of the timing shall apply from the beginning of subframe n+6. When the UE’s uplink PUCCH/PUSCH/SRS transmissions in subframe n and subframe n+1 are overlapped due to the timing adjustment, the UE shall transmit complete subframe n and not transmit the overlapped part of subframe n+1. If the received downlink timing changes and is not compensated or is only partly compensated by the uplink timing adjustment without