Energy-Detection based False Alarm Reduction in Polar-Coded Uplink Control Channel Transmission in 5G-NR

In the uplink transmission scenario, the base station needs to perform a hypothesis test on the existence of desired packets. However, despite the absence of the desired signal, a false alarm (FA) may occur if the hypothesis test is wrong and the cyclic redundancy check is passed. The FA should be avoided as they may incur system malfunctions or unnecessary resource consumption including buffer contaminations [14]. In this paper, we propose a pre-processing for CW detection to prescreen the FAs by investigating the energy of the received signal. Whereas the conventional solutions to mitigate the FA are basically in-decoder schemes, such as CRC or path-metric-based detection schemes [4], [5], the energy-based detection can be performed prior to the decoding trial. We develop a systematic threshold selection rule based on the finite-length performance of the employed channel code. We show that our energy-based detection scheme outperforms conventional FA mitigation methods for the additive white Gaussian noise channel, and even works efficiently for the Rayleigh fading channel.