要提高正交频分复用(OFDM)雷达通信共享信号的通信速率,子载波须采用高阶正交幅度调制(QAM),则需要深入研究QAM-OFDM共享信号的雷达处理性能。针对此问题,研究了高阶QAM对匹配滤波及目标检测性能的影响,得出了信噪比损失公式和推广的目标检测概率公式。理论推导与仿真结果表明:大于四阶的QAM调制使OFDM共享信号在匹配滤波过程中产生了信噪比损失,而提高时宽带宽积可以有效减小这种损失,当时宽带宽积大于256时,QAM-OFDM共享信号具有与常规雷达信号基本相同的目标检测性能,并且提高调制阶数几乎不会影响其性能。由此证明了高阶QAM-OFDM信号是一种适用于高速通信的雷达通信一体化共享信号。

To improve the communication rate of integrated radar and communication (RadCom) signals based on orthogonal frequency division multiplexing (OFDM), data should be modulated by high-order quadrature amplitude modulation (QAM) on each subcarrier, therefore the radar signal performance of QAM-OFDM RadCom signals deserves lucubration. To solve this problem, the influence on match filtering and target detection performance brought by QAM is studied. Moreover, the formula of signal-to-noise ratio (SNR) loss and generalized target detection probability is deduced. Theoretical derivation and simulation results show that QAM with order greater than four leads to the SNR loss in the process of match filtering, but the loss can be alleviated by increasing the time bandwidth product. When the time bandwidth product is greater than 256, the performance of QAM-OFDM RadCom signals are almost the same with the conventional radar signals. Besides, the performance won′t be degraded by enhancing the modulation order. This indicates that QAM-OFDM RadCom signals are suitable for high speed communication in the RadCom system.

TN957.51

国家自然科学基金资助项目