Question: In SL-RTT positioning, what is the primary purpose of measuring the Rx-Tx time difference using SL-PRS transmitted/received by a pair of UEs (e.g., target UE and anchor UE)?
Option 1: To synchronize the clocks between the UEs for voice call optimization
Option 2: To estimate the signal strength between the pair of UEs for handover decisions
Option 3: To calculate the range estimate (distance) between the pair of UEs for positioning purposes
Option 4: To adjust the transmission power for reducing interference in the network
Explanation: The correct answer is Option 3 because, according to the principles of SL-RTT positioning, measuring the Rx-Tx time difference (Round Trip Time - RTT) between two UEs allows for the calculation of a range estimate, which is essentially the distance between these UEs. This distance information is crucial for determining the position of the target UE in relation to known locations (e.g., of anchor UEs), thereby facilitating positioning in the NG-RAN.