ScholarWorks@중앙대학교

초록

The orthogonal time frequency space (OTFS)- based integrated sensing and communication system has gained attention due to their ability to achieve reliable sensing and communication performance in high-mobility environments with severe channel variation. In particular, we consider the delay ambiguity problem in OTFS-based ISAC systems, which occurs when the propagation delay of reflected signal from target exceed the maximum detectable delay defined by the system parameters. Since the delay ambiguity problem results unwrapped delay estimates and reduces the sensing accuracy, we overcome this problem by fully using the phase differences between received pilot symbols. First, we design pilot symbols for OTFS-based ISAC systems in the delay–Doppler (DD) domain, embedding pilots that share the same delay bin but occupy different Doppler bins. The designed pilots shows different phase values in DD-domain with respect to Doppler bin indices, therefore the quasi-periodicity of Zak transform in DD domain enables to estimate how many number of delay periods the received pilots exceed. The proposed method is verified with multi-targets simulations with respect to signal to noise ratio (SNR) and the number of embedded pilots. The results show that the proposed achieves high success probability in estimating the number of exceeded delay periods even in multi-target scenarios and low-SNR conditions.

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