A Two-Step IR-UWB TOA Estimation Method Based on Two-Bit ADC

Time-of-arrival (TOA) estimator design for impulse radio ultra-wideband (IR-UWB) ranging demands high sampling rate high resolution ADC, which is difficult to implement. Some tradeoffs can be made such as limiting amplitude resolution. In this paper, we propose a two-step threshold selection TOA estimator using a two-bit ADC. The quantization threshold of ADC is set as the coarse threshold to distinguish between noise samples (NS) and signal samples (SS). Training-based Decision-Vector (DV) maximum likelihood (ML) estimation and the closed-form expression of early detection probability are presented. Based on early detection control, a simple but effective criteria to determine the fine threshold is proposed. The effects on the performance of training sequence length and coarse threshold, as well as fine threshold are simulated. It is also demonstrated that the proposed method is superior to conventional ED methods via simulation.