Millimeter-wave joint radar and communication system based on photonic frequency-multiplying constant envelope LFM-OFDM

Abstract

The joint radar and communication (JRC) system providing both large-capacity transmission and high-resolution ranging will play a pivotal role in the next-generation wireless networks (e.g., 6G and beyond) and defense applications. Here, we propose and experimentally demonstrate a novel photonics-assisted millimeter-wave (mm-wave) JRC system with a multi-Gbit/s data rate for communication function and centimeter-level range resolution for radar function. The key is the design of the intermediate-frequency (IF) JRC signal through the angle modulation of the linear frequency modulation (LFM) radar carrier using orthogonal frequency division multiplexing (OFDM) communication signal, inspired by the idea of constant-envelope OFDM (CE-OFDM). This IF angle-modulated waveform facilitates the broadband photonic frequency (phase)-multiplying scheme to generate mm-wave JRC signal with multiplied instantaneous bandwidth and phase modulation index for high-resolution LFM radar and noise-robust CE-OFDM communication. It is with fixed low power-to-average power ratio to render robustness against the nonlinear distortions. In proof-of-concept experiments, a 60-GHz JRC signal with an instantaneous bandwidth over 10-GHz is synthesized through a CE-LFM-OFDM signal encoded with a 2-GBaud 16-QAM OFDM signal. Consequently, a 1.5-cm range resolution of two-dimension imaging and an 8-Gbit/s data rate are achieved for both radar and communication functions, respectively. Furthermore, the proposed JRC system is able to achieve higher radar range resolution and better anti-noise communication, when using higher-order photonic frequency multiplying.

Target Detection in Challenging Environments: Photonic Radar with a Hybrid Multiplexing Scheme for 5G Autonomous Vehicles

“…The proposed photonic radar can distinguish two simulated point targets placed within the distance of 8.3 mm. In another work [23], the authors proposed a photonic assisted millimeter wave radar, which can perform a communication function as well as a radar function. The proposed joint communication and radar system can provide a range resolution of 1.5 cm and an 8 Gbps data rate.…”

Power line time transfer technology based on LFM-OFDM and DS-OFDM modulation

“…The main advantages of using LFM signals for modulation (also known as Chirp signals) include simple modulation process and insensitivity to Doppler frequency shift. At present, the LFM-OFDM modulation method has been studied in fields such as optical communication, radar, and underwater acoustic communication [11]. Experimental results show that this modulation method can improve the transmission signal power and reception signal resolution.…”

“…According to formula (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), it can be seen that the frequency of the Chirp signal can change with time and the transformation of K. The linear frequency modulation process is the process of matching the Up chirp signal or Down chirp signal with the baseband signal. When the baseband signal chip data is' 0 ', the Down chirp signal is selected, and when the data is' 1', the Up chirp signal is selected.…”

Human Movement Recognition Based on 3D Point Cloud Spatiotemporal Information from Millimeter-Wave Radar

“…Moreover, these studies are able to recognize single or relatively straightforward human actions, but far less research has been conducted about complex human actions and the different aspects of complex scenes. Therefore, in this paper, we utilize millimeter-wave radar 3D point cloud to conduct experiments in five scenes under two experimental environments to recognize four basic human actions [22][23][24]. In the experiment, the interference of the environment and dynamic objects cannot be avoided, and only by obtaining the point cloud that excludes the interference of the environment can the recognition rate of the human body action be improved.…”