Code-Length Optimization for Polar-Coded OTFS Modulation via Tensor Decomposition

The polar-coded OTFS system is applicable to high-speed mobile communication scenarios. However, the interplay between polar code and OTFS modulation remains a critical challenge in system design since a longer code length improves error-correction performance as well as degrades Doppler-shift robustness. In this letter, we propose a code length optimization algorithm for a polar-coded OTFS modulation system. By introducing a channel model parameterized by a number of physical characteristics, we associate the channel state information with the received signal in terms of code length, angle, delay, channel gain, and Doppler shift. Then, we propose a novel adaptive code-length optimization algorithm via tensor-based approach to achieve better BER performance. Simulation results show that different code lengths exert a discernible influence on the BER performance of the polar-coded OTFS system, demonstrating the necessity for the proposed optimization research, and also indicate that selecting the optimal code length can enhance the BER performance of the system.