Handling of radio frequency front-end group delays for round trip time estimation
摘要
說(shuō)明書(shū)
Since the UE 102 can also be the transmitter 502 or the receiver 504, terms “UE transmission group delay” (generically denoted by txgd(i,k) above, now particularized to refer to UE node) and “UE reception group delay” (generically denoted by rxgd(i,k) above, now particularized to refer to UE node) will be used for convenience to refer to transmission and reception delays occurring at the UE. That is, the UE transmission GD indicates the time interval between a measured transmission time of a signal (e.g., measured RTTR transmit time) and the actual transmission time of the signal (e.g., actual RTTR transmit time). Also, the UE reception GD indicates the time interval between an actual arrival time of a signal (e.g., actual RTTM arrival time) and the measured arrival time of the signal (e.g., measured RTTM arrival time). The term “UE total group delay” will be used to refer to the sum of the UE transmission and reception GDs, i.e.: UE total GD=UE transmission GD+UE reception GD??(9).
Then the actual round trip time between the network node and the UE may be calculated as the measured total time minus the measured turn-around time at the receiver minus the delays at the network node and the UE. That is: actual RTT=(t4?t1)?(t3?t2)?(network total GD+UE total GD)??(10) or actual RTT=(t4?t1)+(t2?t3)?(network total GD+UE total GD)??(10a)
From equations (10), (10a), it can be readily deduced that an accurate RTT may be determined when the total GDs of the network and the UE are known. Also, note that since the receiver is aware of its own total GD, it can readily calculate the actual turn-around time from the measured turn-around time. That is, if the UE is the receiver,
