Mitigating Cross-Link Interference in OFDM Subband Full Duplex Under Timing Misalignment

Subband full-duplex (SBFD) communication has emerged as a promising paradigm for enhancing spectral efficiency in modern wireless networks by enabling simultaneous uplink (UL) and downlink (DL) transmissions within the same frequency band. However, when timing misalignment (TMA) between UL and DL orthogonal frequency-division multiplexing (OFDM) signals exceeds the cyclic prefix (CP) duration, UL subcarriers from user equipment (UE) leak into the DL subcarriers, resulting in substantial cross-link interference (CLI). To address these limitations, we propose the use of zero-padding (ZP)-OFDM waveform for the SBFD slots. The inherent structure of ZP-OFDM allows for block processing of the received frame, enabling effective suppression of inter-UE CLI even in the presence of TMA, thereby eliminating the need for a guard band between the UL and DL sub-bands and significantly enhancing the practicality of SBFD systems.