A Message Passing-Assisted Iterative Noise Cancellation Method for Clipped OTFS-BFDM Systems.

Area of Science:

• Wireless communication systems
• Signal processing

Background:

• Orthogonal Time Frequency Space-Bi-Orthogonal Frequency Division Multiplexing (OTFS-BFDM) offers advantages over OFDM, including lower out-of-band emission and enhanced robustness in high-mobility scenarios.
• However, OTFS-BFDM systems face challenges with high peak-to-average ratio (PAPR) in large data packets, which is often addressed by clipping and filtering (CF).
• Clipping noise introduced by CF degrades signal quality and increases the bit error rate (BER).

Purpose of the Study:

• To propose and evaluate a Message Passing-assisted Iterative Cancellation (MP-AIC) method for mitigating clipping noise in OTFS-BFDM systems.
• To improve the bit error rate (BER) performance of clipped OTFS-BFDM signals by effectively canceling clipping noise.
• To accelerate the convergence of the decoding process in OTFS-BFDM systems.

Main Methods:

• The study adopts a one-iteration clipping and filtering (OCF) technique at the transmitter to reduce PAPR.
• A novel MP-AIC method is developed, integrating traditional Message Passing (MP) decoding with iterative clipping noise cancellation at the receiver.
• The MP-AIC method iteratively refines the cancellation by using the variance of the residual signal and channel noise as inputs for MP decoding and employing the convergence probability to accelerate subsequent iterations.

Main Results:

• The proposed MP-AIC method significantly enhances the accuracy of MP decoding in clipped OTFS-BFDM systems.
• MP-AIC effectively accelerates the convergence of BER performance.
• Simulations demonstrate that MP-AIC with two iterations can reduce BER by over 72% compared to systems without clipping noise cancellation in rectangular pulse-shaped OTFS-BFDM systems.

Conclusions:

• The MP-AIC method presents an effective solution for clipping noise cancellation in OTFS-BFDM systems.
• This approach improves both decoding accuracy and convergence speed, leading to substantial BER reductions.
• The MP-AIC technique offers a promising strategy for enhancing the performance of high-mobility wireless communication systems utilizing OTFS-BFDM.