Monobit Digital Receivers for QPSK Modulation Using Impulse Radio
Future communication system requires large bandwidths to achieve high data rates, rendering high-resolution analog-to-digital converter (ADC) a key bottleneck due to its high complexity and large power consumption. In this paper, we consider monobit digital receivers for QPSK modulation. First, the optimal monobit receiver under Nyquist sampling is derived. Its performance is calculated in the form of deflection ratio. Then a suboptimal but low-complexity monobit receiver is obtained. The impact of the phase offset is investigated, and the interface with error-control decoder is given. Numerical simulations show that the low-complexity suboptimal receiver suffers 3dB signal to noise ratio (SNR) loss in AWGN channels and only 1dB SNR loss in multipath channels compared with the matched-filter based monobit receiver with full channel state information (CSI).