Time Offset (5G NR/5G-Advanced)
is the offset to the Analysis Start Boundary and is expressed relative to the trigger t=0 point when Trigger Delay = 0 sec. When Trigger Delay is non-zero, then Trigger Delay will be subtracted from the Time Offset value.
The time offset will not exceed the analysis boundary period length (any integer multiple of the analysis boundary period will be subtracted from the TimeOffset).
Accurate Time Offset Measurement of Recorded Signals using Periodic Playback Trigger
3GPP and O-RAN Radio Access Network conformance test requires accurate measurement of Time Offset because its value is very small when the trigger location is the start of a radio frame. This has previously been difficult to achieve with 5G NR measurements using recorded signals because the start time in the recording is not taken into consideration in the measurement. In previous releases, Free Run Playback Trigger was used in measuring Time Offset, and the VSA software used the 2nd frame in a recording to find the frame boundary. After settling time, the accuracy of the Time Offset measurement was within a few milliseconds. Using Periodic Playback Trigger (with Sync Source = Recording Trigger), Time Offset is now relative to the trigger location (T=0) in the recording, and for ideal signal, Time Offset measurement with an accuracy of less than 1 nanosecond is achievable.
See Also
