FBMC-OTFS Waveform Design for Integrated Sensing and Communications

HUA Kunyi; SONG Chen; LIANG Wei; DAI Lingjun

doi:10.11999/JEIT260845

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HUA Kunyi, SONG Chen, LIANG Wei, DAI Lingjun. FBMC-OTFS Waveform Design for Integrated Sensing and Communications[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260845

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HUA Kunyi, SONG Chen, LIANG Wei, DAI Lingjun. FBMC-OTFS Waveform Design for Integrated Sensing and Communications[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260845

HUA Kunyi, SONG Chen, LIANG Wei, DAI Lingjun. FBMC-OTFS Waveform Design for Integrated Sensing and Communications[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260845

Citation:

HUA Kunyi, SONG Chen, LIANG Wei, DAI Lingjun. FBMC-OTFS Waveform Design for Integrated Sensing and Communications[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260845

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FBMC-OTFS Waveform Design for Integrated Sensing and Communications

doi: 10.11999/JEIT260845 cstr: 32379.14.JEIT260845

HUA Kunyi^{1, 2, 3
,},
SONG Chen^{1, 2, 3
,
,},
LIANG Wei^{1, 2, 3},
DAI Lingjun⁴

1.
National Key Laboratory of Microwave Imaging Technology, Beijing 100094, China
2.
Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China
3.
School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
4.
Hangzhou Institute of Technology, Xidian University, Hangzhou 311231, China

Received Date: 2026-06-22
Accepted Date: 2026-10-15
Rev Recd Date: 2026-10-11

Available Online: 2026-10-22

Abstract

Abstract

Objective With the continuous advancement of 6G and integrated sensing and communication (ISAC) technologies, wireless communications are progressively moving towards high-mobility scenarios. In such environments, traditional orthogonal frequency division multiplexing (OFDM) signals are susceptible to Doppler shifts, which compromise the orthogonality of subcarriers and introduce inter-carrier interference, thereby degrading communication performance. OTFS signals, constructed on a discrete delay-Doppler two-dimensional grid, exhibit robust resilience to time-varying channels because each symbol experiences nearly the same channel effect during transmission. However, the limited delay and Doppler resolutions of OTFS waveforms inevitably lead to fractional delays and fractional Doppler shifts in practical applications, which cause dispersion effects that impair both communication capabilities and target detection performance in ISAC systems. This paper aims to mitigate the dispersion effects in OTFS signals and enhance the stability and reliability of ISAC systems through waveform and signal processing design. Methods This paper employs a low-sidelobe prototype filter from the filter bank multicarrier (FBMC) family to modulate the OTFS signal. The prototype filter effectively suppresses Doppler sidelobes and mitigates Doppler dispersion effects, while introducing only marginal mainlobe widening compared with an OTFS waveform carrying the same number of data symbols. A guard interval is established between communication data symbols and radar pilots in the delay-Doppler domain to prevent mutual interference, thereby establishing the FBMC-OTFS signal model. In channel modeling, fractional delays and fractional Doppler shifts are jointly considered to accurately characterize the practical channel. Furthermore, drawing on the constant false alarm rate (CFAR) algorithm widely used in radar detection, channel estimation is performed for the FBMC-OTFS system in the delay-Doppler domain, improving target detection accuracy while reducing computational complexity. Finally, the maximum ratio combining (MRC) algorithm is applied to signal detection, iteratively eliminating inter-symbol interference to reduce the bit error rate. Results and Discussions This paper presents both simulation and field experiment results in multi-path channel scenarios, comparing the proposed FBMC-OTFS waveform with traditional OTFS waveforms. The results show that when the power difference between the strong and weak targets is 18.5 dB, the FBMC-OTFS signal can still detect the weaker target, whereas the OTFS waveform fails to do so. When both waveforms successfully detect all targets (at a 9 dB strong-to-weak target power difference), FBMC-OTFS achieves a significantly lower bit error rate (BER) than OTFS at an SNR of 20 dB. Moreover, the Doppler sidelobes of the FBMC-OTFS signal are nearly imperceptible, while those of the OTFS signal are distinctly visible: the peak sidelobe ratio (PSLR) and integrated sidelobe ratio (ISLR) of FBMC-OTFS are reduced to −29.82 dB and −22.15 dB, respectively. This sidelobe suppression is achieved at the cost of a reduced spectral efficiency, which is approximately one eighth of that of conventional OTFS. Field experiments further validate the feasibility of the FBMC-OTFS waveform in practical ISAC scenarios. Conclusions This paper proposes an FBMC-OTFS waveform tailored for ISAC applications, along with its corresponding signal processing methods. By modulating the OTFS waveform with the PHYDYAS prototype filter, the proposed approach effectively suppresses Doppler dispersion effects and mitigates the mutual interference between communication data and radar pilots, enabling reliable weak-target detection. The established channel model jointly accounts for fractional delays and fractional Doppler shifts. The CFAR algorithm, originally developed for radar detection, is applied to channel estimation, achieving robust path detection while reducing computational complexity, and is complemented by an MRC-based signal detector. Simulation and field experiments demonstrate that, compared with traditional OTFS, FBMC-OTFS significantly reduces Doppler sidelobes and can detect weak targets that OTFS fails to resolve, at the cost of a reduced spectral efficiency of about one eighth. The results provide a viable waveform solution for ISAC applications in 6G high-mobility scenarios.
- ISAC,
- FBMC,
- OTFS,
- wireless communication,
- radar sensing

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References(37)

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