Optimization of frequency-shifted reference ultrawideband systems

Recently, there has been significant interest in developing ultrawideband (UWB) radio techniques. A transmitted reference (TR)-UWB technique is often considered for low-to-moderate data rate applications. However, the TR-UWB technique is limited by the difficulty in building the required highly accurate wideband analog delay line in the receiver. Frequency-shifted reference (FSR)-UWB avoids this analog delay by shifting the reference signal from the data signal in frequency, and FSR-UWB has been shown to outperform the standard TR-UWB scheme. The performance of the FSR-UWB system has been further improved in succeeding work by sending multiple data signals that share a common reference carrier, referred to as multi-differential (MD) FSR, but this comes with a significant increase in the peak-to-average power (PAPR) of the pulses. In this paper, three improvements are proposed for the FSR-UWB system: the front-end filter and the integration time at the receiver are optimized, and a PAPR minimization scheme for the MD-FSR scheme is introduced. After describing and characterizing these approaches, simulation results are provided to consider the varying degrees of improvement offered through the proposed techniques.