恒包络OFDM雷达通信一体化信号设计
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摘要
为利用同一信号同时实现雷达探测与通信传输,设计了一种恒包络OFDM雷达通信一体化信号。首先,对信号相位进行调制,将其分为通信调制项与雷达调制项;其次,设计通信调制项为OFDM相位乘以加权系数,并利用矢量合成的方法定量分析了其对雷达的影响,确定了通信加权系数的取值标准;然后,设计雷达调制项为一组余弦函数的和,并通过设置各余弦函数的调制系数,改变信号的模糊函数使雷达适用于不同场景;最后,利用三角函数的正交性及雷达波形确定性确立了解调步骤。仿真结果表明,当调制系数为随机序列时,能够得到图钉状模糊函数;在相同参数设置下,相比于传统恒包络OFDM信号,脉压后设计信号的第一旁瓣降低了25 dB,主瓣宽度降低了7倍,利于实现雷达高分辨率、高检测概率探测,且随着序列长度增加,距离分辨率提高;通过控制通信加权系数的大小,可在雷达和通信性能之间取得最佳折中。
An extended constant envelope OFDM signal for an integrated radar and communi-cation system is proposed to perform radar detection and communication simultaneously. Phase modulations are performed to divide a phase into two parts, i.e., communication modulation and radar modulation. Communication modulation function is the real part of OFDM with a weighted coefficient. A vertical resultant theorem is introduced to quantitatively analyze the effect of embedded communication symbols on radar waveform performance and to ascertain the weighted coefficient of the communication modulation function. Radar modulation term is designed to be a sum of a series of cosine functions, and the modulation coefficient of each cosine function is set to change the ambiguity function shape of the signal and to make the radar suitable for different scenes. Orthogonality of trigonometric functions and certainty of radar waveforms are employed to establish the demodulation procedure. Simulation results show that a thumbtack-like ambiguity function is obtained by setting the modulation coefficient as a random sequence. The first side lobe of the designed signal is 25 dB lower than that of the original constant envelope OFDM signal, and the main lobe width is reduced by a factor of seven under the same setting parameters of a given context. Thus, high range resolution and Doppler resolution are achieved. The range resolution improves when the length of the random sequence increases. The best balance between radar performance and the communication bit error rate can be achieved through controlling the size of weighted coefficient of communication.
An extended constant envelope OFDM signal for an integrated radar and communi-cation system is proposed to perform radar detection and communication simultaneously. Phase modulations are performed to divide a phase into two parts, i.e., communication modulation and radar modulation. Communication modulation function is the real part of OFDM with a weighted coefficient. A vertical resultant theorem is introduced to quantitatively analyze the effect of embedded communication symbols on radar waveform performance and to ascertain the weighted coefficient of the communication modulation function. Radar modulation term is designed to be a sum of a series of cosine functions, and the modulation coefficient of each cosine function is set to change the ambiguity function shape of the signal and to make the radar suitable for different scenes. Orthogonality of trigonometric functions and certainty of radar waveforms are employed to establish the demodulation procedure. Simulation results show that a thumbtack-like ambiguity function is obtained by setting the modulation coefficient as a random sequence. The first side lobe of the designed signal is 25 dB lower than that of the original constant envelope OFDM signal, and the main lobe width is reduced by a factor of seven under the same setting parameters of a given context. Thus, high range resolution and Doppler resolution are achieved. The range resolution improves when the length of the random sequence increases. The best balance between radar performance and the communication bit error rate can be achieved through controlling the size of weighted coefficient of communication.
引文
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[7] 刘永军,廖桂生,杨志伟,等.一种超分辨OFDM雷达通信一体化设计方法 [J].电子与信息学报,2016,38(2):425-433.LIU Yongjun,LIAO Guisheng,YANG Zhiwei,et al.A super-resolution design method for integrated of OFDM radar and communication [J].Journal of Electronic & Information Technology,2016,38(2):425-433.
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[11] 肖涛,任光亮.恒包络OFDM雷达通信一体化研究 [J].雷达科学与技术,2018,16(5):491-495.XIAO Tao,REN Guangliang.Research on integrated radar and communication system based on constant envelope OFDM [J].Radar Science and Technology,2018,16(5):491-495.
[12] TSAI Y M,ZHANG G D,PAN J L.Orthogonal frequency division multiplexing with phase modulation and constant envelope design [C] //Proceedings of IEEE Military Communications Conference MILCOM.Piscataway,NJ,USA:IEEE,2005:2658-2664.
[13] SAHIN C,JAKABOSKY J,MCCORMICK P M,et al.A novel approach for embedding communication symbols into physical radar waveforms [C] //2017 Radar Conference.Piscataway,NJ,USA:IEEE,2017:1498-1503.
[14] ZHANG Yu,LI Qingyu,HUANG Ling,et al.A modified waveform design for radar-communication integration based on LFM-CPM [C] //2017 IEEE 85th Vehicular Technology Conference.Piscataway,NJ,USA:IEEE,2017:1-5.
[15] CHEN Xingbo,WANG Xiaomo,XU Shanfeng,et al.A novel radar waveform compatible with communication [C] //2011 International Conference on Computational Problem-Solving.Piscataway,NJ,USA:IEEE,2011:177-181.
[16] 李晓柏,杨瑞娟,陈新永,等.基于分数阶傅里叶变换的雷达通信一体化信号共享研究 [J].信号处理,2012,28(4):487-494.LI Xiaobo,YANG Ruijuan,CHEN Xinyoug,et al.The sharing signal for integrated radar and communication based on FRFT [J].Signal Processing,2012,28(4):487-494.
[17] 周宇,杨慧婷,谷亚彬,等.基于调频率调制的雷达通信一体化信号研究 [J].电子科技大学学报,2017,46(6):830-835.ZHOU Yu,YANG Huiting,GU Yabin,et al.Study on integrated radar and communication signal based on chirp-rate modulation [J].Journal of University of Electronic Science and Technology of China,2017,46(6):830-835.
[18] 谷亚彬,张林让,周宇.采用FRFT-OFDM的雷达通信功能共享方法 [J].西安电子科技大学学报,2017,44(6):48-52.GU Yabin,ZHANG Linrang,ZHOU Yu.Integration of the radar and communication method with FRFT-OFDM signals [J].Journal of Xidian University,2017,44(6):48-52.
[19] 杨慧婷,周宇,谷亚彬,等.参数调制多载波雷达通信共享信号设计 [EB/OL].(2018-07-13) [2018-09-30].http:// kns.cnki.net/kcms/detail/10.1030.TN.20180713.1852.002.html.
[20] BLUNT S D,COOK M R,STILES J.Embedding information into radar emissions via waveform implementation [C] // 2010 International Waveform Diversity and Design Conference.Piscataway,NJ,USA:IEEE,2010:195-199.
[21] O’CONNOR A C,KANTOR J M,JAKABOSKY J.Joint equalization filters that mitigate waveform-diversity modulation of clutter [C] //2016 IEEE Radar Conference.Piscataway,NJ,USA:IEEE,2016:7485173.
[22] 陈伯孝,杨林,朱伟,等.现代雷达系统分析与设计 [M].西安:西安电子科技大学出版社,2012:121-122.
[2] 陈兴波,王小谟,曹晨,等.雷达通信综合化波形设计技术分析 [J].现代雷达,2013,35(12):56-63.CHEN Xingbo,WANG Xiaomo,CAO Chen,et al.Techniques analysis of radar-communication integration waveform [J].Modern Radar,2013,35(12):56-63.
[3] 李明兵,谷亚彬,张林让,等.一种OFDM雷达通信一体化的距离超分辨方法 [J].电讯技术,2017,57(6):622-628.LI Mingbing,GU Yabin,ZHANG Linrang,et al.A range super-resolution method for integration of OFDM radar and communication [J].Telecommunication Engineering,2017,57(6):622-628.
[4] HUGH G,LAWRENCE C,SIMON W,et al.Radar spectrum engineering and management:technique and regulatory issues [J].Proceedings of the IEEE,2015,103(1):85-102.
[5] 霍凯,赵晶晶.OFDM新体制雷达研究现状与发展趋势 [J].电子与信息学报,2015,37(11):2776-2789.HUO Kai,ZHAO Jingjing.The development and prospect of the new OFDM radar [J].Journal of Electronics & Information Technology,2015,37(11):2776-2789.
[6] 杨慧婷.基于线性调频信号的雷达通信一体化信号研究 [D].西安:西安电子科技大学,2018:1-2.
[7] 刘永军,廖桂生,杨志伟,等.一种超分辨OFDM雷达通信一体化设计方法 [J].电子与信息学报,2016,38(2):425-433.LIU Yongjun,LIAO Guisheng,YANG Zhiwei,et al.A super-resolution design method for integrated of OFDM radar and communication [J].Journal of Electronic & Information Technology,2016,38(2):425-433.
[8] 谷亚彬,张林让,周宇,等.采用相关函数的OFDM雷达通信一体化设计方法 [J].西安电子科技大学学报,2018,45(4):1-7.GU Yabin,ZHANG Linrang,ZHOU Yu,et al.OFDM radar and communication sharing signal processing using the correlation function [J].Journal of Xidian University,2018,45(4):1-7.
[9] TIAN Xuanxuan,SONG Zhaohui.On radar and communication integrated system using OFDM signals [C]// 2017 IEEE Radar Conference.Piscataway,NJ,USA:IEEE,2017:0318-0323.
[10] STURM C,WIESBECK W.Waveform design and signal processing aspects for fusion of wireless communications and radar sensing [J].Proceedings of the IEEE,2011,99(7):1236-1259.
[11] 肖涛,任光亮.恒包络OFDM雷达通信一体化研究 [J].雷达科学与技术,2018,16(5):491-495.XIAO Tao,REN Guangliang.Research on integrated radar and communication system based on constant envelope OFDM [J].Radar Science and Technology,2018,16(5):491-495.
[12] TSAI Y M,ZHANG G D,PAN J L.Orthogonal frequency division multiplexing with phase modulation and constant envelope design [C] //Proceedings of IEEE Military Communications Conference MILCOM.Piscataway,NJ,USA:IEEE,2005:2658-2664.
[13] SAHIN C,JAKABOSKY J,MCCORMICK P M,et al.A novel approach for embedding communication symbols into physical radar waveforms [C] //2017 Radar Conference.Piscataway,NJ,USA:IEEE,2017:1498-1503.
[14] ZHANG Yu,LI Qingyu,HUANG Ling,et al.A modified waveform design for radar-communication integration based on LFM-CPM [C] //2017 IEEE 85th Vehicular Technology Conference.Piscataway,NJ,USA:IEEE,2017:1-5.
[15] CHEN Xingbo,WANG Xiaomo,XU Shanfeng,et al.A novel radar waveform compatible with communication [C] //2011 International Conference on Computational Problem-Solving.Piscataway,NJ,USA:IEEE,2011:177-181.
[16] 李晓柏,杨瑞娟,陈新永,等.基于分数阶傅里叶变换的雷达通信一体化信号共享研究 [J].信号处理,2012,28(4):487-494.LI Xiaobo,YANG Ruijuan,CHEN Xinyoug,et al.The sharing signal for integrated radar and communication based on FRFT [J].Signal Processing,2012,28(4):487-494.
[17] 周宇,杨慧婷,谷亚彬,等.基于调频率调制的雷达通信一体化信号研究 [J].电子科技大学学报,2017,46(6):830-835.ZHOU Yu,YANG Huiting,GU Yabin,et al.Study on integrated radar and communication signal based on chirp-rate modulation [J].Journal of University of Electronic Science and Technology of China,2017,46(6):830-835.
[18] 谷亚彬,张林让,周宇.采用FRFT-OFDM的雷达通信功能共享方法 [J].西安电子科技大学学报,2017,44(6):48-52.GU Yabin,ZHANG Linrang,ZHOU Yu.Integration of the radar and communication method with FRFT-OFDM signals [J].Journal of Xidian University,2017,44(6):48-52.
[19] 杨慧婷,周宇,谷亚彬,等.参数调制多载波雷达通信共享信号设计 [EB/OL].(2018-07-13) [2018-09-30].http:// kns.cnki.net/kcms/detail/10.1030.TN.20180713.1852.002.html.
[20] BLUNT S D,COOK M R,STILES J.Embedding information into radar emissions via waveform implementation [C] // 2010 International Waveform Diversity and Design Conference.Piscataway,NJ,USA:IEEE,2010:195-199.
[21] O’CONNOR A C,KANTOR J M,JAKABOSKY J.Joint equalization filters that mitigate waveform-diversity modulation of clutter [C] //2016 IEEE Radar Conference.Piscataway,NJ,USA:IEEE,2016:7485173.
[22] 陈伯孝,杨林,朱伟,等.现代雷达系统分析与设计 [M].西安:西安电子科技大学出版社,2012:121-122.