OTFS雷达通信一体化复用波形设计
OTFS Radar Communication Integrated Multiplexed Waveform Design
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摘要: 随着无线通信技术的发展,雷达和通信频段逐渐相互重叠,使得雷达通信一体化成为了缓解频谱资源紧张的最好的实现方法之一。作为雷达通信一体化的主要载体之一,正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)的波形设计方法可分为两大类,一类是复用波形设计,另一类是共用波形设计。由于共用波形设计需要考虑雷达和通信性能之间的折中,且在雷达信号处理过程和通信接收端需要设计专门的处理流程,因此在频谱资源较为充足时,基于OFDM的复用波形设计比起共用设计优势更明显。由于OFDM对多普勒的敏感性高,基于OFDM的复用波形设计不适用于高速运动场景。针对这一问题,本文提出了一种基于正交时频空(Orthogonal Time Frequency Space,OTFS)的雷达通信一体化复用波形设计。这种设计利用OTFS多普勒容忍性高的特点,可实现高速运动场景下的雷达通信一体化。鉴于OTFS的时延-多普勒域和雷达的快时间慢时间概念相似,本文采用多普勒复用的方法实现了一体化复用信号设计,并提出了该波形下的通信和雷达接收端的处理流程。通信接收端通过OTFS解调可实现高速通信,雷达接收端无须进行波形分离,可直接利用常规雷达信号处理流程完成目标信息的估计。本文通过仿真验证了所提一体化复用波形的可行性,同时通过仿真验证了所提波形在高速运动场景上,相比于OFDM体制复用波形在雷达目标参数估计和通信误码率上的优势。Abstract: As wireless communication technology advances, the overlapping of radar and communication frequency bands has become more pronounced. Integrating radar and communication systems emerges as a promising solution to mitigate the scarcity of spectrum resources. Orthogonal frequency division multiplexing (OFDM), which is one of the main carriers of radar communication integration, can divide waveform design methods into two categories: one is the multiplexed waveform design, the other is the common waveform design. Common waveform design requires balancing radar and communication performance, necessitating special processing flows in both radar signal processing and communication reception. In cases where spectrum resources are abundant, the advantages of multiplexed waveform design based on OFDM become more apparent compared to traditional waveform designs. Due to the high sensitivity of OFDM to Doppler, the multiplexed waveform design based on OFDM is not suitable for high-speed motion scenarios. To solve this problem, this paper proposes a radar communication integrated multiplexed waveform design based on orthogonal time frequency space (OTFS). This design used the high tolerance of OTFS Doppler to realize the integration of radar communication in high-speed motion scenarios. Considering the similarity of the delay-Doppler domain of OTFS and the fast time and slow time of radar, this study used Doppler multiplexing to realize an integrated multiplexed signal design and used the communication and radar receiver processing flow under this waveform. The communication receiver could realize high-speed communication through OTFS demodulation; the radar receiver did not need to perform waveform separation and could directly complete the target information estimation using the conventional radar signal processing process. In this study, the feasibility of the proposed integrated multiplexed waveform is verified by simulation, and the advantages of the proposed waveform in radar target parameter estimation and communication bit error rate compared with the OFDM multiplexed waveform in high-speed motion scenarios are verified through simulation.