Waveform design with constant peak-to-average power ratio: Waveform design and performance analysis

This chapter focuses on the waveform design of joint radar and communication systems with a particular emphasis on maintaining a constant peak-to-average power ratio (PAPR). Maintaining a constant PAPR is highly desirable for the efficient use of the radio frequency hardware for radar. In this chapter, we design a new waveform based on phase and frequency shift keying modulation. The new waveform communicates data and senses the environment while maintaining a constant PAPR. New analytical tools are derived to characterize the performance of the proposed waveform both in terms of radar sensing and communications operations. The work is further extended to consider a permutation based joint waveform which makes use of the full available bandwidth and results in improved radar performance. Furthermore, we discuss systematic approaches to select subsets of waveforms to either improve radar or communications performance. In terms of the radar sensing operation, we derive analytical expressions for the ambiguity function of the proposed waveforms based on which the delay and the Doppler estimation accuracies are discussed. In terms of the communications performance, we consider the optimal maximum likelihood detector and derive expressions for the block error probability. Numerical examples are provided to illustrate the performance of the proposed waveform both in terms of the radar sensing performance and communications performance. Finally, the chapter discusses several interesting extensions and open research problems in the area of waveform design for joint communications and radar sensing.