Waveform Design for Joint Radar-Communication with Nonideal Power Amplifier and Outband Interference

The joint radar-communication system is a good way to meet the intelligent transportation systems' need of detecting the cars and barriers around and exchanging information from each other at the same time. Among various schemes, the joint system with integrated waveform attracts general interest because the interference between the radar and communication subsystems will be fundamentally avoided. For all kinds of integrated waveforms, the spectrum must be limited within B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , the original working band of the radar, in order to avoid the performance loss brought by the attenuation of the power amplifier (PA) and the interference from other devices out of band, which is inevitable in actual devices and environment. In this paper, the time-frequency characteristics of an integrated waveform based on Linear Frequency Modulation (LFM) and Continuous Phase Modulation (CPM) is studied in detail with the Short Time Fourier Transform (STFT). Based on the theoretical analysis, a modified three-section waveform with a limit of the mapping codebook of communication symbols is proposed. Simulation results show that the bandwidth of the modified waveform is limited within B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and the bit error rate (BER) performance with a band-limited PA and out-band interference is almost the same as the BER with ideal PA and no interference.