Dithering and ΣΔ modulation in mono-bit digital receivers for ultra-wideband communications

Ultra-wideband (UWB) systems employ short, low power pulses. Analog receiver designs can accommodate the required bandwidths, but come at a cost of reduced flexibility. Digital approaches, on the other hand, provide flexibility in receiver signal processing but are limited by analog-to-digital (ADC) resolution and power consumption. In this paper we consider reduced complexity digital receivers, in which the ADC is limited to a single bit per sample. We study three one-bit ADC schemes: fixed reference, stochastic reference, and sigma-delta modulation (SDM). These are compared for two types of receivers based on (i) matched filtering, and (ii) a transmitted-reference. Bit error rate (BER) expressions are developed for these systems, and compared to full resolution implementations with negligible quantization error. The analysis includes the impact of quantization noise, filtering, and oversampling. In particular, for an additive white Gaussian noise channel, we show that the SDM scheme with oversampling can achieve the BER performance of a full resolution digital receiver.