以正弦波为载波的正交频分复用（OFDM）是5G通信的主流调制技术，但OFDM对系统同步及子载波间正交性要求苛刻，接收解调中任何微小载波频偏都会破坏其正交性引起信道间干扰，因此本项目提出基于线性调频特性的Chirp调制来对抗频偏敏感问题。且不同调频速率的Chirp调制，具有载波自身携带信息量的优势从而构成多维复合调制，以提高系统信息传输速率；并利用Chirp信号时频特征实现多载波复用，来提高系统频带利用率。重点开展以下研究：调制解调系统多参数间数学建模；调制信号参数优化与时频多载波复用；加权分数傅里叶变换（WFRFT）与最佳接收机相结合的解调；短波频段信号传输仿真实验与外场测试。研究中重点解决的关键科学问题：Chirp系统数学建模中多目标函数参数寻优问题；WFRFT多载波复用频带利用率与误码率协调平衡输出问题。从而取得创新性研究成果，为多维复合调制与多载波复用提供坚实理论基础与关键技术储备。

Orthogonal frequency division multiplexing (OFDM) with sine-wave carrier is the mainstream modulation technology in 5G communication, while the synchronization and subcarrier orthogonality are demanded strictly. Due to whatever tiny carrier frequency offset in the receiver, the orthogonality among the signals might be destroyed which will cause inter-channel interference. Thus, the Chirp modulation with linear frequency characteristics is proposed to against the sensitivities to frequency offset. And the Chirp modulation with different frequency rate carrying information can constitute multi-dimensional composite modulation scheme to improve the rate of information transmission. The Chirp signals can be realized multicarrier multiplexing based on its time-frequency characteristics to improve the bandwidth efficiency. The main research will be carried out in the following: mathematical modeling of multiple parameters of modulation and demodulation; parameters optimization of modulation signal and multicarrier multiplexing; the best demodulation of combined weighted fractional Fourier transform (WFRFT) with the principle of optimal receiver; Simulation of signal transmission in short-wave band and field test. The critical problems to be solved in the research process are: parameter optimization of mathematical model with multi-objective for Chirp system; the output balance between bandwidth efficiency and error probability in multicarrier multiplexing system by WFRFT. It is expected that some innovative achievements will be published, and solid theoretical foundation as a key technical reserve for the multi-dimensional composite modulation communication and multicarrier multiplexing can be put forward.