-
摘要: 在电子信息系统对抗中,雷达、通信、侦察机和干扰机等多种电子设备通过简单的功能叠加式配备于作战平台已经难以应对敌方的综合性电子兵器,因此,多种电子设备的综合一体化是现代战争环境装备发展的必然趋势。其中,作为战场“千里眼”和“顺风耳”的雷达和通信设备无论在硬件结构还是在信号处理方法上都具有极强的相似性,两者的有机结合具有很强的实现性。因此,通感一体化(DFRC)系统受到了广泛的关注。其中,DFRC信号设计是DFRC系统研究的关键科学问题之一,通过电磁频谱共享方式,在空域、时域以及频域等多个维度上,同时实现雷达探测和信息通信两种功能。该文对以感知功能(雷达探测功能)为主功能的DFRC信号设计方法进行了深入、系统的综述。该文简要介绍了面向战场环境的DFRC系统的相关项目,进一步讨论了DFRC信号设计的研究进展。并在最后总结全文并对未来的研究方向进行了展望。Abstract: During the confrontation of electronic systems, it is challenging to deal with the enemy’s comprehensive electronic weapons by simply combining electronic equipment, such as radar, communication, surveillance, and jammers. Hence, to meet the requirements of a modern war environment, the comprehensive integration of various electronic equipment is an inevitable trend. Radar and communication equipment, which are viewed as forward eyes and ears, are very similar in hardware structure and signal processing methods. In this regard, the organic union of these two is plausible. As a result, the Dual-Function Radar and Communication (DFRC) system has received a lot of attention, where integrated waveform design is one of the key scientific issues. The DFRC waveform primarily refers to the transmit waveform that realizes radar detection and information communication functions simultaneously in multiple dimensions, such as space, time, and frequency domains, through electromagnetic spectrum sharing. This paper provides a fundamental review of the radar-centric DFRC waveform design. Initially, this paper presents a brief overview of the radar-centric DFRC system’s application scenarios. Then, the progress of radar-centric integrated waveform design research is discussed. Finally, some closing remarks and potential future research directions are provided.
-
图 3 脉冲位置通信信息调制示意图(
${I_1}$ :第1个询问脉冲,${I_2}$ :第2个询问脉冲,${R_0}$ :比特0的参考脉冲位置,${R_1}$ :比特1的参考脉冲位置,${R_{\rm{start}}}$ :开始标识脉冲,P:该位置上存在脉冲,—:该位置上没有脉冲)Figure 3. Diagram of pulse position for communication information embedding (
${I_1}$ : the first inquiry pulse,${I_2}$ : the second inquiry pulse,${R_0}$ : reference pulse position of bit 0,${R_1}$ : reference pulse position of bit 1,${R_{\rm{start}}}$ : start identifying pulse, P: existing pulse at present position, —: without pulse at present position)表 1 SISO系统DFRC信号设计优缺点
Table 1. Summary of dual-function signal design methods in SISO system
信息调制方法 优点 缺点 PRI捷变[34-36] 1. 不影响信号自相关函数性能2. 通信误码率低 1. 影响雷达探测的最大不模糊距离2. 通信速率较低 基于LFM信号的PSK调制[37-40] 1. 保留了与LFM信号的相似性,从而具有较好的多普勒容忍度2. 通信误码率和PSK调制相当 1. 信号的自相关旁瓣较LFM信号升高,影响雷达探测性能2. 通信速率较低 频域置零调制[43]、模糊函数置零调制[44]、全盲水印调制[45](均采用优化理论信号设计) 1. 优化的探测性能函数多样,可以从不同的角度保证雷达探测性能2. 雷达性能和通信性能的权衡部分取决于优化参数设定,因而具有一定的可控可调整性 1. 通信速率较低2. 通信误码率取决于信息的调制和解调方式 表 2 MIMO系统一体化信号设计优缺点
Table 2. Summary of dual-function signal design methods in MIMO system
-
[1] 刘永军, 廖桂生, 李海川, 等. 电磁空间分布式一体化波形设计与信息获取[J]. 中国科学基金, 2021, 35(5): 701–707. doi: 10.16262/j.cnki.1000-8217.2021.05.005LIU Yongjun, LIAO Guisheng, LI Haichuan, et al. Distributed integrated waveform design and information acquisition in electromagnetic space[J]. Bulletin of National Natural Science Foundation of China, 2021, 35(5): 701–707. doi: 10.16262/j.cnki.1000-8217.2021.05.005 [2] HUGHES P K and CHOE J Y. Overview of advanced multifunction RF system (AMRFS)[C]. 2000 IEEE International Conference on Phased Array Systems and Technology, Dana Point, USA, 2000: 21–24. [3] TAVIK G C, HILTERBRICK C L, EVINS J B, et al. The advanced multifunction RF concept[J]. IEEE Transactions on Microwave Theory and Techniques, 2005, 53(3): 1009–1020. doi: 10.1109/TMTT.2005.843485 [4] MOLNAR J A, CORRETJER I, and TAVIK G. Integrated topside-integration of narrowband and wideband array antennas for shipboard communications[C]. 2011 Military Communications Conference, Baltimore, USA, 2011: 1802–1807. [5] WETZEL L B. Sea Clutter[M]. SKOLNIK M I. Radar Handbook. 2nd ed. New York: McGraw-Hill, 1990: 13.23–13.24. [6] JENSEN D. Radar transmitting data[EB/OL]. https://www.aviationtoday.com/2006/08/01/radar-transmitting-data/, 2006. [7] BROUSSEAU R, SANDERS A, HUFFMAN D R, et al. An open system architecture for integrated RF systems[C]. 16th DASC. AIAA/IEEE Digital Avionics Systems Conference. Reflections to the Future, Irvine, USA, 1997: 5.1–1. doi: 10.1109/DASC.1997.635082. [8] WU Kai, ZHANG J A, HUANG Xiaojing, et al. Waveform design and accurate channel estimation for frequency-hopping MIMO radar-based communications[J]. IEEE Transactions on Communications, 2021, 69(2): 1244–1258. doi: 10.1109/TCOMM.2020.3034357 [9] WU Kai, ZHANG J A, HUANG Xiaojing, et al. Reliable frequency-hopping MIMO radar-based communications with multi-antenna receiver[J]. IEEE Transactions on Communications, 2021, 69(8): 5502–5513. doi: 10.1109/TCOMM.2021.3079270 [10] LIU Fan, MASOUROS C, LI Ang, et al. MU-MIMO communications with MIMO radar: From co-existence to joint transmission[J]. IEEE Transactions on Wireless Communications, 2018, 17(4): 2755–2770. doi: 10.1109/TWC.2018.2803045 [11] LIU Fan, ZHOU Longfei, MASOUROS C, et al. Toward dual-functional radar-communication systems: Optimal waveform design[J]. IEEE Transactions on Signal Processing, 2018, 66(16): 4264–4279. doi: 10.1109/TSP.2018.2847648 [12] LIU Fan, MASOUROS C, and GRIFFITHS H. Dual-functional radar-communication waveform design under constant-modulus and orthogonality constraints[C]. 2019 Sensor Signal Processing for Defence Conference, Brighton, UK, 2019: 1–5. [13] LIU Fan, MASOUROS C, RATNARAJAH T, et al. On range sidelobe reduction for dual-functional radar-communication waveforms[J]. IEEE Wireless Communications Letters, 2020, 9(9): 1572–1576. doi: 10.1109/LWC.2020.2997959 [14] TSINOS C G, ARORA A, CHATZINOTAS S, et al. Joint transmit waveform and receive filter design for dual-function radar-communication systems[J]. IEEE Journal of Selected Topics in Signal Processing, 2021, 15(6): 1378–1392. doi: 10.1109/JSTSP.2021.3112295 [15] LIU Rang, LI Ming, LIU Qian, et al. Joint waveform and filter designs for STAP-SLP-based MIMO-DFRC systems[J]. IEEE Journal on Selected Areas in Communications, 2022, 40(6): 1918–1931. doi: 10.1109/JSAC.2022.3155501 [16] 刘永军, 廖桂生, 唐皓, 等. FSK-FMCW雷达通信一体化信号设计与处理方法研究[J]. 信号处理, 2022, 38(11): 2265–2275. doi: 10.16798/j.issn.1003-0530.2022.11.004LIU Yongjun, LIAO Guisheng, TANG Hao, et al. Integrated FSK-FMCW radar and communication signal design and processing method[J]. Journal of Signal Processing, 2022, 38(11): 2265–2275. doi: 10.16798/j.issn.1003-0530.2022.11.004 [17] ZHAO Na, WANG Yunlong, ZHANG Zhibo, et al. Joint transmit and receive beamforming design for integrated sensing and communication[J]. IEEE Communications Letters, 2022, 26(3): 662–666. doi: 10.1109/LCOMM.2021.3140093 [18] STURM C and 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. doi: 10.1109/JPROC.2011.2131110 [19] SEN S. PAPR-constrained pareto-optimal waveform design for OFDM-STAP radar[J]. IEEE Transactions on Geoscience and Remote Sensing, 2013, 52(6): 3658–3669. [20] HUANG Yixuan, HU Su, MA Shiyong, et al. Constant envelope OFDM RadCom fusion system[J]. EURASIP Journal on Wireless Communications and Networking, 2018, 2018: 104. doi: 10.1186/s13638-018-1105-6 [21] LIU Yongjun, LIAO Guisheng, YANG Zhiwei, et al. Design of integrated radar and communication system based on MIMO-OFDM waveform[J]. Journal of Systems Engineering and Electronics, 2017, 28(4): 669–680. doi: 10.21629/JSEE.2017.04.06 [22] LIU Yongjun, LIAO Guisheng, YANG Zhiwei, et al. Joint range and angle estimation for an integrated system combining MIMO radar with OFDM communication[J]. Multidimensional Systems and Signal Processing, 2019, 30(2): 661–687. doi: 10.1007/s11045-018-0576-2 [23] LIU Yongjun, LIAO Guisheng, CHEN Yufeng, et al. Super-resolution range and velocity estimations with OFDM integrated radar and communications waveform[J]. IEEE Transactions on Vehicular Technology, 2020, 69(10): 11659–11672. doi: 10.1109/TVT.2020.3016470 [24] LIU Yongjun, LIAO Guisheng, and YANG Zhiwei. Robust OFDM integrated radar and communications waveform design based on information theory[J]. Signal Processing, 2019, 162: 317–329. doi: 10.1016/j.sigpro.2019.05.001 [25] LIU Yongjun, LIAO Guisheng, YANG Zhiwei, et al. Multiobjective optimal waveform design for OFDM integrated radar and communication systems[J]. Signal Processing, 2017, 141: 331–342. doi: 10.1016/j.sigpro.2017.06.026 [26] LIU Yongjun, LIAO Guisheng, XU Jingwei, et al. Adaptive OFDM integrated radar and communications waveform design based on information theory[J]. IEEE Communications Letters, 2017, 21(10): 2174–2177. doi: 10.1109/LCOMM.2017.2723890 [27] 刘永军, 廖桂生, 杨志伟. 基于OFDM的雷达通信一体化波形模糊函数分析[J]. 系统工程与电子技术, 2016, 38(9): 2008–2018. doi: 10.3969/j.issn.1001-506X.2016.09.07LIU Yongjun, LIAO Guisheng, and YANG Zhiwei. Ambiguity function analysis of integrated radar and communication waveform based on OFDM[J]. Systems Engineering and Electronics, 2016, 38(9): 2008–2018. doi: 10.3969/j.issn.1001-506X.2016.09.07 [28] 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. doi: 10.11999/JEIT150320LIU Yongjun, LIAO Guisheng, YANG Zhiwei, et al. A super-resolution design method for integration of OFDM radar and communication[J]. Journal of Electronics &Information Technology, 2016, 38(2): 425–433. doi: 10.11999/JEIT150320 [29] 刘永军, 廖桂生, 杨志伟. OFDM雷达通信一体化波形相参积累研究[J]. 信号处理, 2017, 33(3): 253–259. doi: 10.16798/j.issn.1003-0530.2017.03.001LIU Yongjun, LIAO Guisheng, and YANG Zhiwei. A study for the coherent integration with integrated radar and communication waveform based on OFDM[J]. Journal of Signal Processing, 2017, 33(3): 253–259. doi: 10.16798/j.issn.1003-0530.2017.03.001 [30] TEMIZ M, ALSUSA E, and BAIDAS M W. A dual-functional massive mimo ofdm communication and radar transmitter architecture[J]. IEEE Transactions on Vehicular Technology, 2020, 69(12): 14974–14988. doi: 10.1109/TVT.2020.3031686 [31] TEMIZ M, ALSUSA E, and BAIDAS M W. Optimized precoders for massive MIMO OFDM dual radar-communication systems[J]. IEEE Transactions on Communications, 2021, 69(7): 4781–4794. doi: 10.1109/TCOMM.2021.3068485 [32] TIAN Tuanwei, ZHANG Tianxian, KONG Lingjiang, et al. Transmit/receive beamforming for MIMO-OFDM based dual-function radar and communication[J]. IEEE Transactions on Vehicular Technology, 2021, 70(5): 4693–4708. doi: 10.1109/TVT.2021.3072094 [33] JOHNSTON J, VENTURINO L, GROSSI E, et al. MIMO OFDM dual-function radar-communication under error rate and beampattern constraints[J]. IEEE Journal on Selected Areas in Communications, 2022, 40(6): 1951–1964. doi: 10.1109/JSAC.2022.3156651 [34] MEALEY R M. A method for calculating error probabilities in a radar communication system[J]. IEEE Transactions on Space Electronics and Telemetry, 1963, 9(2): 37–42. doi: 10.1109/TSET.1963.4337601 [35] FIDEN W H and CZUBIAK D W. Radar-compatible data link system[P]. US, 7298313B1, 2007. [36] 刘智星, 全英汇, 肖国尧, 等. 基于PRI捷变的雷达通信一体化共享信号设计方法[J]. 系统工程与电子技术, 2021, 43(10): 2836–2842. doi: 10.12305/j.issn.1001-506X.2021.10.17LIU Zhixing, QUAN Yinghui, XIAO Guoyao, et al. Signal design method for integrated radar and communication based on PRI agility[J]. Systems Engineering and Electronics, 2021, 43(10): 2836–2842. doi: 10.12305/j.issn.1001-506X.2021.10.17 [37] SADDIK G N, SINGH R S, and BROWN E R. Ultra-wideband multifunctional communications/radar system[J]. IEEE Transactions on Microwave Theory and Techniques, 2007, 55(7): 1431–1437. doi: 10.1109/TMTT.2007.900343 [38] 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): 56–59. doi: 10.16592/j.cnki.1004-7859.2013.12.016CHEN Xingbo, WANG Xiaomo, CAO Chen, et al. Techniques analysis of radar-communication integrating waveform[J]. Modern Radar, 2013, 35(12): 56–59. doi: 10.16592/j.cnki.1004-7859.2013.12.016 [39] 刘志鹏. 雷达通信一体化波形研究[D]. [博士论文], 北京理工大学, 2015.LIU Zhipeng. Waveform research on integration of radar and communication[D]. [Ph. D. dissertation], Beijing Institute of Technology, 2015. [40] 付月, 崔国龙, 盛彪. 基于LFM信号相位/调频率调制的探通一体化共享信号设计[J] 现代雷达, 2018, 40(6): 41–46, 53.FU Yue, CUI Guolong, and SHENG Biao. Integrated radar and communication signal design based on phase/chirp rate modulated LFM signal[J] Modern Radar, 2018, 40(6): 41–46, 53. [41] SAHIN C, JAKABOSKY J, MCCORMICK P M, et al. A novel approach for embedding communication symbols into physical radar waveforms[C]. 2017 IEEE Radar Conference, Seattle, USA, 2017: 1498–1503. [42] 杨超. 传感通信一体化FMCW波形设计与信号处理[D]. [博士论文], 桂林电子科技大学, 2020.YANG Chao. Sensing and communication integration waveform designing and signal processing based on FMCW[D]. [Ph. D. dissertation], Guilin University of Electronic Technology, 2020. [43] CUI Guolong, YANG Jing, LU Shuping, et al. Dual-use unimodular sequence design via frequency nulling modulation[J]. IEEE Access, 2018, 6: 62470–62481. doi: 10.1109/ACCESS.2018.2876644 [44] YANG Jing, CUI Guolong, YU Xianxiang, et al. Dual-use signal design for radar and communication via ambiguity function sidelobe control[J]. IEEE Transactions on Vehicular Technology, 2020, 69(9): 9781–9794. doi: 10.1109/TVT.2020.3002773 [45] YANG Jing, TAN Youshan, YU Xianxiang, et al. Waveform design for watermark framework based DFRC system with application on joint SAR imaging and communication[J]. IEEE Transactions on Geoscience and Remote Sensing, 2023, 61: 5200214. doi: 10.1109/TGRS.2022.3232528 [46] HASSANIEN A, HIMED B, and RIGLING B D. A dual-function MIMO radar-communications system using frequency-hopping waveforms[C]. 2017 IEEE Radar Conference, Seattle, USA, 2017: 1721–1725. [47] EEDARA I P, AMIN M G, and HASSANIEN A. Controlling clutter modulation in frequency hopping MIMO dual-function radar communication systems[C]. 2020 IEEE International Radar Conference, Washington, USA, 2020: 466–471. [48] EEDARA I P, HASSANIEN A, and AMIN M G. Performance analysis of dual-function multiple-input multiple-output radar-communications using frequency hopping waveforms and phase shift keying signalling[J]. IET Radar, Sonar & Navigation, 2021, 15(4): 402–418. doi: 10.1049/rsn2.12043 [49] EEDARA I P, AMIN M G, and HOORFAR A. Optimum code design using genetic algorithm in frequency hopping dual function MIMO radar communication systems[C]. 2020 IEEE Radar Conference, Florence, Italy, 2020: 1–6. [50] EEDARA I P, AMIN M G, and FABRIZIO G A. Target detection in frequency hopping MIMO dual-function radar-communication systems[C]. 2021 IEEE International Conference on Acoustics, Speech and Signal Processing, Toronto, Canada, 2021: 8458–8462. [51] EEDARA I P, AMIN M G, HOORFAR A, et al. Dual-function frequency-hopping MIMO radar system with CSK signaling[J]. IEEE Transactions on Aerospace and Electronic Systems, 2022, 58(3): 1501–1513. doi: 10.1109/TAES.2021.3139445 [52] HASSANIEN A, AMIN M G, ZHANG Y D, et al. Dual-function radar-communications: Information embedding using sidelobe control and waveform diversity[J]. IEEE Transactions on Signal Processing, 2016, 64(8): 2168–2181. doi: 10.1109/TSP.2015.2505667 [53] HASSANIEN A, AMIN M G, ZHANG Y D, et al. Signaling strategies for dual-function radar communications: An overview[J]. IEEE Aerospace and Electronic Systems Magazine, 2016, 31(10): 36–45. doi: 10.1109/MAES.2016.150225 [54] HASSANIEN A, AMIN M G, ZHANG Y D, et al. Efficient sidelobe ASK based dual-function radar-communications[C]. SPIE 9829, Radar Sensor Technology XX, Baltimore, USA, 2016: 98290K. [55] EUZIÈRE J, GUINVARC’H R, LESTURGIE M, et al. Dual function radar communication time-modulated array[C]. 2014 International Radar Conference, Lille, France, 2014: 1–4. [56] HASSANIEN A, AMIN M G, ZHANG Y D, et al. Phase-modulation based dual-function radar-communications[J]. IET Radar, Sonar & Navigation, 2016, 10(8): 1411–1421. doi: 10.1049/iet-rsn.2015.0484 [57] HASSANIEN A, AMIN M G, ZHANG Y D, et al. Non-coherent PSK-based dual-function radar-communication systems[C]. 2016 IEEE Radar Conference, Philadelphia, USA, 2016: 1–6. [58] AHMED A, ZHANG Y D, and HIMED B. Multi-user dual-function radar-communications exploiting sidelobe control and waveform diversity[C]. 2018 IEEE Radar Conference, Oklahoma, USA, 2018: 698–702. [59] AHMED A, ZHANG Y D, and GU Yujie. Dual-function radar-communications using QAM-based sidelobe modulation[J]. Digital Signal Processing, 2018, 82: 166–174. doi: 10.1016/j.dsp.2018.06.018 [60] HASSANIEN A, VOROBYOV S A, and KHABBAZIBASMENJ A. Transmit radiation pattern invariance in MIMO radar with application to DOA estimation[J]. IEEE Signal Processing Letters, 2015, 22(10): 1609–1613. doi: 10.1109/LSP.2015.2417220 [61] GEMECHU A Y, CUI Guolong, YU Xianxiang, et al. Beampattern synthesis with sidelobe control and applications[J]. IEEE Transactions on Antennas and Propagation, 2020, 68(1): 297–310. doi: 10.1109/TAP.2019.2938730 [62] GEMECHU A Y, CUI Guolong, YU Xianxiang, et al. Phase-only beampattern synthesis with nulling for linear antenna arrays[C]. 2019 IEEE International Symposium on Phased Array System & Technology, Waltham, USA, 2019: 1–7. [63] YU Xianxiang, YAO Xue, YANG Jing, et al. Integrated waveform design for MIMO radar and communication via spatio-spectral modulation[J]. IEEE Transactions on Signal Processing, 2022, 70: 2293–2305. doi: 10.1109/TSP.2022.3170687 [64] WU Wenhua, HAN Guojun, CAO Yunhe, et al. MIMO waveform design for dual functions of radar and communication with space-time coding[J]. IEEE Journal on Selected Areas in Communications, 2022, 40(6): 1906–1917. doi: 10.1109/JSAC.2022.3155508 [65] TANG Bo and STOICA P. MIMO multifunction RF systems: Detection performance and waveform design[J]. IEEE Transactions on Signal Processing, 2022, 70: 4381–4394. doi: 10.1109/TSP.2022.3202315 [66] DI RENZO M, HAAS H, GHRAYEB A, et al. Spatial modulation for generalized MIMO: Challenges, opportunities, and implementation[J]. Proceedings of the IEEE, 2014, 102(1): 56–103. doi: 10.1109/JPROC.2013.2287851 [67] BASAR E. Index modulation techniques for 5G wireless networks[J]. IEEE Communications Magazine, 2016, 54(7): 168–175. doi: 10.1109/MCOM.2016.7509396 [68] BAŞAR E. OFDM with index modulation using coordinate interleaving[J]. IEEE Wireless Communications Letters, 2015, 4(4): 381–384. doi: 10.1109/LWC.2015.2423282 [69] HASSANIEN A, ABOUTANIOS E, AMIN M G, et al. A dual-function MIMO radar-communication system via waveform permutation[J]. Digital Signal Processing, 2018, 83: 118–128. doi: 10.1016/j.dsp.2018.08.010 [70] 杨婧, 余显祥, 沙明辉, 等. MIMO系统探通一体化信号矩阵设计方法[J]. 雷达学报. 待出版YANG Jing, YU Xianxiang, SHA Minghui, et al. Dual function radar and communication signal matrix design method for MIMO system[J]. Journal of Radars, in press [71] WANG Xiangrong, HASSANIEN A, and AMIN M G. Dual-function MIMO radar communications system design via sparse array optimization[J]. IEEE Transactions on Aerospace and Electronic Systems, 2019, 55(3): 1213–1226. doi: 10.1109/TAES.2018.2866038 [72] BAXTER W, ABOUTANIOS E, and HASSANIEN A. Dual-function MIMO radar-communications via frequency-hopping code selection[C]. 2018 52nd Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, USA, 2018: 1126–1130. [73] BAXTER W, ABOUTANIOS E, and HASSANIEN A. Joint radar and communications for frequency-hopped MIMO systems[J]. IEEE Transactions on Signal Processing, 2022, 70: 729–742. doi: 10.1109/TSP.2022.3142909 [74] HUANG Tianyao, SHLEZINGER N, XU Xingyu, et al. MAJoRCom: A dual-function radar communication system using index modulation[J]. IEEE Transactions on Signal Processing, 2020, 68: 3423–3438. doi: 10.1109/TSP.2020.2994394 [75] MA Dingyou, SHLEZINGER N, HUANG Tianyao, et al. FRaC: FMCW-based joint radar-communications system via index modulation[J]. IEEE Journal of Selected Topics in Signal Processing, 2021, 15(6): 1348–1364. doi: 10.1109/JSTSP.2021.3118219 [76] XU Jing, WANG Xiangrong, ABOUTANIOS E, et al. Hybrid index modulation for dual-functional radar communications systems[J]. IEEE Transactions on Vehicular Technology, 2023, 72(3): 3186–3200. doi: 10.1109/TVT.2022.3219888 [77] KOBAYASHI M, CAIRE G, and KRAMER G. Joint state sensing and communication: Optimal tradeoff for a memoryless case[C]. 2018 IEEE International Symposium on Information Theory, Vail, USA, 2018: 111–115. [78] KOBAYASHI M, HAMAD H, KRAMER G, et al. Joint state sensing and communication over memoryless multiple access channels[C]. 2019 IEEE International Symposium on Information Theory, Paris, France, 2019: 270–274. [79] WEINER I. High-SNR channel capacity for communication over radar waveforms[J]. IEEE Transactions on Aerospace and Electronic Systems, 2019, 55(3): 1261–1268. doi: 10.1109/TAES.2018.2884858 [80] LIU Xiang, HUANG Tianyao, LIU Yimin, et al. Achievable sum-rate capacity optimization for joint MIMO multiuser communications and radar[C]. 2021 IEEE 22nd International Workshop on Signal Processing Advances in Wireless Communications, Lucca, Italy, 2021: 466–470. [81] 刘凡, 袁伟杰, 原进宏, 等. 雷达通信频谱共享及一体化: 综述与展望[J]. 雷达学报, 2021, 10(3): 467–484. doi: 10.12000/JR20113LIU Fan, YUAN Weijie, YUAN Jinhong, et al. Radar-communication spectrum sharing and integration: Overview and prospect[J]. Journal of Radars, 2021, 10(3): 467–484. doi: 10.12000/JR20113 [82] 马丁友, 刘祥, 黄天耀, 等. 雷达通信一体化: 共用波形设计和性能边界[J]. 雷达学报, 2022, 11(2): 198–212. doi: 10.12000/JR21146MA Dingyou, LIU Xiang, HUANG Tianyao, et al. Joint radar and communications: Shared waveform designs and performance bounds[J]. Journal of Radars, 2022, 11(2): 198–212. doi: 10.12000/JR21146 [83] MA Dingyou, SHLEZINGER N, HUANG Tianyao, et al. Bit constrained communication receivers in joint radar communications systems[C]. 2021 IEEE International Conference on Acoustics, Speech and Signal Processing, Toronto, Canada, 2021: 8243–8247. [84] CHENG Ziyang, SHI Shengnan, HE Zishu, et al. Transmit sequence design for dual-function radar-communication system with one-bit DACs[J]. IEEE Transactions on Wireless Communications, 2021, 20(9): 5846–5860. doi: 10.1109/TWC.2021.3070586 [85] YU Xiaoyou, YANG Qi, XIAO Zhu, et al. A precoding approach for dual-functional radar-communication system with one-bit DACs[J]. IEEE Journal on Selected Areas in Communications, 2022, 40(6): 1965–1977. doi: 10.1109/JSAC.2022.3155532