Performance Analysis of Uplink Joint Communication and Sensing System

As various emerging services put forward higher demands for the spectrum utilization efficiency in sixth generation (6G) network, the joint communication and sensing (JCS) has become one of the leading trends of technologies towards 6G. In this paper, we propose an efficient method of evaluating the performance of target detection for the uplink JCS system. Specifically, for physically separated transceivers, the noise and communication decoding error cannot be ignored in the LOS (line of sight) path. This study considers the influence of these factors on detection accuracy. We simultaneously estimate the delay and Doppler shift to obtain the range and velocity information of the target by analyzing the frequency domain correlation between the echo signal and the recovered transmitted signal. Moreover, the Cramer-Rao lower bound (CRLB) for the uplink system has been formulated. Based on numerical simulations, we derived the uplink CRLBs on the estimation accuracy of the target range and velocity. Besides, the impact of noise and decoding error on target detection in different communication quadrature amplitude modulation (QAM) orders is demonstrated.