In this study, we propose index modulation (IM) with circularly-shifted chirps (CSCs) (CSC-IM) for dual-function radar and communication (DFRC) systems. The proposed scheme encodes the information bits with the CSC indices and the phase-shift keying (PSK) symbols. It allows the receiver to exploit the frequency selectivity naturally in fading channels by combining IM and wideband CSCs. It also leverages the fact that a CSC is a constant-envelope signal to achieve a controllable peak-to-mean envelope power ratio (PMEPR). For radar functionality, CSC-IM maintains the good autocorrelation (AC) properties of a chirp by ensuring that the transmitted CSCs are separated apart sufficiently in the time domain through index separation (IS). We investigate the impact of IS on spectral efficiency (SE) and obtain the corresponding mapping functions. For theoretical results, we derive the union bound (UB) of the block error rate (BLER) for arbitrary chirps and the Cramer-Rao lower bounds (CRLBs) for the range and reflection coefficients for the matched filter (MF)-based estimation. We also prove that complementary sequences (CSs) can be constructed through CSCs by linearly combining the Fourier series of CSCs. Finally, through comprehensive comparisons, we demonstrate the efficacy of the proposed scheme for DFRC scenarios.
翻译:在本研究中,我们提议对双功能雷达和通信系统采用循环转换的调制(IM)指数调制(IM),对双功能雷达和通信系统采用循环转换的调制(CSC-IM),将信息比特与CSC指数和级档密钥符号编码,使接收者能够通过将IM和宽频带综合控制系统与宽频CSC组合,在淡化的渠道中自然地利用频率选择性。它还利用了以下事实,即CSC是一个恒定的信号,以便实现可控制的最高到中值信封比率(PMEPR)。对于雷达功能,CSC-IM通过指数分离(IS),确保传输的CSC指数指数指数和级键性符号在时间域中充分分离,从而保持了一个精度的好自动调校正(AC)。 我们调查了IS对光谱效率的影响,并获得了相应的绘图功能。 关于理论结果,我们从块误差率(BUB)中得出一个可以控制的最高比值,而CRB为CRC值和C-RAw较低约束序列,对于雷达的调值(CR)保持一个好的调和CMSC-CSB,通过我们通过CR校准的缩定序校准,也可以校校校校校准,通过R校正的校正的校正的C-C-C-CR校正的校正校正校正的校正校正校正的校正校正的校正,通过我们校正的校正校正的校正校正的校正的校正校正校正校正校正校正校正校正校正校正的校正校正校正校正校正校正校正校正校正校正校正校正校正校正,通过校正校正校正校正校正校正校正校正校正校正,通过校正校方的校方的校方的校正,可以校正校正。