Rethink Delay Doppler Channels and Time-Frequency Coding

Xiang-Gen Xia

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arXiv · 2501.00641

Rethink Delay Doppler Channels and Time-Frequency Coding

Xiang-Gen Xia

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Abstract

In this paper, we rethink delay Doppler channels (also called doubly selective channels). We prove that no modulation schemes (including the current active VOFDM/OTFS) can compensate a non-trivial Doppler spread well. We then discuss some of the existing methods to deal with time-varying channels, in particular time-frequency (TF) coding in an OFDM system. TF coding is equivalent to space-time coding in the math part. We also summarize state of the art on space-time coding that was an active research topic over a decade ago.

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Xiang-Gen Xia. 2024-12-31. Rethink Delay Doppler Channels and Time-Frequency Coding. https://arxiv.org/abs/2501.00641

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