ent window=5 ms data transmission) Measurement gap length=6 ms RF retuning time (no data transmission) UE can detect all SSBs by shifting the measurement gap start time SMTC window=5 ms 1 ms- RF retuning time (no Actual measurement window=5 ms data transmission) Measurement gap length=6 ms RF retuning time (no data transmission) Measurement MGL: Measurement gap length Actual MGRP: Measurement gap repetition period measurement window 15 kHz subcarrier spacing window Figure 5.17 Illustration of the concept and usage of measurement gap timing advance 6,29]. 704 Chapter 5 of the candidate cell, it cannot configure such measurement gaps. In that case, the BS would need to configure the measurement gaps with different lengths until the terminal can detect the SSB of the candidate cell. This would increase the signaling overhead and the delay until the UE is able to find and connect to the target gNB. In order to avoid such ineffi- ciency, a new procedure for performing SFTD measurement of candidate gNBs without using measurement gap is defined while maintaining UE's transmission/reception in the cur- rent cell. Fig. 5.18 shows an example of SFTD measurement which incorporates the afore- mentioned procedure. Instead of stopping transmission/reception of data by the RF device to perform measurements, the method uses separate RF device on the terminal, which is used if the UE supports carrier aggregation. When the RF transceiver that is used for mea- surement is turned on or off, the RF transceiver used for data transmission/reception is affected, thus the UE cannot transmit or receive in one subframe before and after the mea- surement window. However, the terminal can transmit/receive data in the current cell while SFTD measurements for neighboring gNBs are being performed. 5.5 Direct RF Sampling Transceivers As analog-to-digital converter (ADC) and digital-to-analog converter (DAC) designs and architectures continue to advance using smaller geometry process nodes, a new class of giga- sample-per-second (GSPS) ADC and DA