Delay alignment modulation (DAM) has been recently proposed to enable manipulable channel delay spread for efficient single- or multi-carrier communications. In particular, with perfect delay alignment, inter-symbol interference (ISI) can be eliminated even with single-carrier (SC) transmission, without relying on sophisticated channel equalization. The key ideas of DAM are delay pre-compensation and path-based beamforming, so that all multi-path signal components may arrive at the receiver simultaneously and be superimposed constructively, rather than causing the detrimental ISI. Compared to the classic orthogonal frequency division multiplexing (OFDM) transmission, DAM-enabled SC communication has several appealing advantages, including low peak-to-average-power ratio (PAPR) and high tolerance for Doppler frequency shift, which renders DAM also appealing for radar sensing. Therefore, in this paper, DAM is investigated for integrated sensing and communication (ISAC) systems. We first study the output signal-to-noise ratios (SNRs) for ISI-free SC communication and radar sensing, and then derive the closed-form expressions for DAM-based sensing in terms of the ambiguity function (AF) and integrated sidelobe ratio (ISR). Furthermore, we study the beamforming design problem for DAM-based ISAC to maximize the communication SNR while guaranteeing the sensing performance in terms of the sensing SNR and ISR. Finally, we provide performance comparison between DAM and OFDM for ISAC, and it is revealed that DAM signal may achieve better communication and sensing performance, thanks to its low PAPR, reduced guard interval overhead, as well as higher tolerance for Doppler frequency shift. Simulation results are provided to show the great potential of DAM for ISAC.
翻译:最近提议了延迟校正调制(DAM),以使所有多路信号组件能够同时到达接收器,并具有建设性,而不是造成破坏性的ISI。与传统的或上层频率多式传输(OFDM)相比,DAM带动的SC通信具有一些吸引人的优势,包括低峰至平均电率(PAPR)和高容忍度的多普勒频率转换,这使得DAM也吸引雷达感应。因此,在本文中,DAM是用于综合感测和通信(ISAC)系统的调查。我们首先研究ISI自由型和雷达多频分级传输(OFDM)传输(OFDM),DAM带动的信号干扰(ISDAM)比(SAM)的输出信号对低音率比。 与SISDR的经典或雷达传输(OFR)比相比,DAM的超峰值比(DAM)可以提供高的SAM(SAM) 和SARC(SAF) 的透明性能表达方式,作为DAM 的自我感测测算法(我们SAM ) 的自我感测测测度和SARC 的SADAM 的缩缩缩缩,作为SADRA 的缩 的系统 的缩 的缩 的缩 的功能,作为SADADADADADR 的缩 的缩 的缩 的缩 。