Effect of Wake-Up Signal Location & Guard RB on Interference Mitigation at Wake-Up Receiver in 5G

Low-Power Wake-Up Signal (LP-WUS) has been introduced in 3GPP NR Release 18 as a key feature for UE power saving. Optimal performance of a LP-WUS Receiver (LR) requires suitable ways of mitigating the interference experienced by the simple LP-WUS signal due to Adjacent Channel Interference (ACI) and In-Channel Interference (ICI). In this paper, we present a simulation study of the Relative Interference Level (RIL) of LP-WUS at the LR taking into account the impact of Guard Resource Blocks (RBs) on either side of LP-WUS, location of LP-WUS within 5G NR channel, Carrier Frequency Offset (CFO) of the LR local oscillator, and the LR filter order. We provide comprehensive simulation results that quantify the RIL, and LP-WUS bandwidth efficiency by proper selection of guard RBs, and positioning of LP-WUS for different scenarios. The simulation analysis shows that the more close LP-WUS is to the channel edge, the larger guard RBs it would require to tackle the ACI. Furthermore, we show that higher ACI puts restriction on how close the LP-WUS can be placed towards the edge.