Coding-Enhanced Range and Velocity Estimation in Uplink OFDM-ISAC Systems

Integrated sensing and communication (ISAC) is expected to be a key technology in the next-generation mobile communication network. Most current researches in ISAC systems focus on downlink sensing. However, the full-duplex technique is not yet mature, thus the self-interference is a significant hurdle that cannot be bypassed. In this paper, we investigate the communication-assisted sensing for uplink ISAC systems. Specifically, a user equipment (UE) transmits an uplink orthogonal frequency division multiplexing (OFDM) signals to the BS for data transmission. Simultaneously, both the UE and the BS perform radar sensing in bistatic mode, using the uplink signals reflected by the targets. The uplink data is first recovered at the BS and then utilized to remove the randomness introduced by the modulated communication symbols. In particular, low-density parity-check (LDPC) codes are employed to enhance communication reliability and sensing accuracy. Simulation results demonstrate that the proposed design can effectively achieve high-precision range and velocity estimation based on the communication signals.