Handling of radio frequency front-end group delays for round trip time estimation
摘要
說明書
Alternatively, the UE may incorporate both the measured turn-around time (t3?t2) and the UE total GD in the RTTR signal. In an example implementation, the UE may include the measured turn-around time (t3?t2) and/or the measured time difference (t2?t3) in the RTTR payload. To indicate the UE total GD, the UE may alter the transmission time of the RTTR signal. For example, the network node can specify a timing advance (TA), which indicates how much the transmission timing should be advanced at the UE. The UE may transmit the RTTR signal at a timing offset from the specified TA by an amount corresponding to the UE total GD. The network node may then interpret the difference between the actual arrival time and the expected arrival time of the RTTR signal as corresponding to the UE total GD. Equation (10) and/or (10a) may then be used to calculate the RTT.
Accuracy of the position location methods may be affected by the characteristics of the RTTM and RTTR signals. For example, in some instances, it may be sufficient to have a coarse (e.g., within a cyclic prefix (CP) duration of Orthogonal Frequency-Division Multiplexing (OFDM) symbols) level time synchronization across gNodeBs. Coarse time-synchronization enables low-reuse of RTTMs, which mitigates intercell interference. Intercell interference mitigation ensures deep penetration of the RTTM signals, which enables multiple independent timing measurements across distinct gNodeBs, and hence more accurate positioning.
