【作者】 陈鹏；

【导师】 汪清；

【作者基本信息】 天津大学 ， 信息与通信工程， 2022， 硕士

【摘要】 双功能通信雷达一体化系统利用统一的波形实现通信和雷达两种功能。联合设计通信雷达一体化系统,可以减少天线数量,减小系统尺寸、重量与能量消耗,提高通信传输速率,有效解决频谱拥挤的问题。针对提高通信雷达一体化系统的通信速率问题,本文设计了基于码域、频域与空域结合的索引调制双功能通信雷达波形。首先设计了频域与空域的索引调制双功能通信雷达波形;随后为进一步提高通信传输速率,设计了码域、频域与空域结合的索引调制波形;最后采用最大似然方法对一体化波形进行解码。仿真结果表明,多域复合的索引调制波形有效提高通信速率,且不占用额外的频谱资源。针对以雷达为主的波形中如何隐蔽地嵌入通信的问题,本文设计了基于线性调频(Linear Frequency Modulation,LFM)chirp信号的通信雷达一体化隐蔽波形。首先设计了基于减小相位差调制的LFM chirp波形,通过随机产生脉冲宽度和调制相位,使得波形中嵌入的通信信息不易被检测到;随后引入码域索引调制技术,进一步增强信息的隐蔽性,并利用码本正交基数量多的特点提高通信速率;最后设计了基于神经网络的低复杂度隐蔽波形解码方法。实验结果表明,与不采取索引调制的方案相比,索引调制可通过利用码本正交基数量的优势提高通信速率。神经网络解码器与最大似然方法相比,误码率性能接近,但处理速度显著提高,与相干解调方法相比,提高了误码率性能。针对给定功率条件下通信与雷达资源竞争问题,本文设计了功能互增强的通信雷达一体化方案。首先,对通信功能而言,雷达发射索引调制的双功能一体化波形,通信接收端同时处理通信信道和雷达信道信息,提高通信速率,实现通信功能增强;对雷达功能而言,通信发射信号可作为外部辐射源雷达的照射源,实现主动雷达和被动雷达功能复合,提高雷达接收机的检测性能。实验结果表明,所设计的功能互增强通信雷达一体化系统的通信和雷达功能都得到了提升,主被动雷达复合模式的目标探测克拉美罗界(Cramér Rao Bound,CRB)优于非协作的主动雷达模式,双功能与直达通道复合模式的通信可达速率优于非协作的直达通信模式,实现功能互增强。更多还原

【Abstract】 The dual-function integrated communication and radar system uses a unified waveform to achieve both communication and radar functions.The joint design of an integrated communication and radar system can reduce the number of antennas,reduce the system size,weight and energy consumption,increase the communication transmission rate,and effectively solve the problem of spectrum congestion.Aiming at the problem of improving the communication rate of the integrated communication and radar system,we extend the index modulation scheme to code,frequency and space domains.Firstly,frequency and space domain index modulation dual-function communication radar waveform are firstly proposed.Combining code domain index modulation,the communication transmission rate is significantly improved.Finally,the maximum likelihood decoder is designed for the hidden waveform.Simulation results show that the multi-domain composite index modulation waveform effectively improves the communication rate without occupying additional spectrum resources.Aiming at the problem of how to covertly embed communication information in radar-based waveforms,we propose an integrated communication and radar covert waveform.Firstly,the linear frequency modulation(LFM)chirp waveform using a novel reduced phase difference modulation is proposed,and the pulse width and modulation phase are randomly generated to make the communication information embedded in the waveform difficult to be detected.Then the code domain index modulation technology is introduced to further enhance the concealment of the information,which can also make use of the large codebook to improve the communication rate.Finally,a low-complexity hidden waveform decoding method based on neural network is designed.Experimental results show that,compared with a scheme that does not adopt index modulation,index modulation can increase the communication rate.The proposed neural network decoder outperformed the maximum likelihood and the coherent demodulation methods,in terms of processing speed and bit error rate performance,respectively.Aiming at the problem of communication and radar resource competition under given power conditions,we provide an integrated communication and radar solution with mutually enhanced functions.First of all,for the communication aspect,the dualfunction radar transmits integrated waveform using index modulation.To improve the communication rate,the communication receiver processes the communication channel and radar channel information at the same time,leading to the enhancement of the communication function.For the radar aspect,the communication transmission signal are treated as the passive radar illumination source.By processing the active and passive radar cooperatively,we greatly improve the target detection performance.Experimental results show that the communication and radar functions are both improved rather than tradeoff,benefitting from the well-designed DFRC/dedicated coexisting communication scheme and the passive/active integrated radar scheme.The mutual enhancement is verified with respect to the Cramér Rao Bound(CRB)and the achievable rate for radar target detection and communication information convey,respectively.更多还原