Communication Limits with Low Precision Analog-to-Digital Conversion at the Receiver

— We examine the Shannon limits of communication systems when the precision of the analog-to-digital conversion (ADC) at the receiver is constrained. ADC is costly and powerhungry at high speeds, hence ADC precision is expected to be a limiting factor in the performance of receivers which are heavily based on digital signal processing. In this paper, we consider a Nyquist sampled system in which the output samples are quantized using a small number of bits, generalizing our prior work on one bit ADC. We show that dithered ADC does not increase capacity and hence we restrict attention to deterministic quantizers. Since the output alphabet is discrete, a dual formulation of the channel capacity problem is useful both for obtaining tight upper bounds on the capacity, as well as for obtaining input distributions that approach these bounds. The numerical results we obtain strongly support our conjecture that the optimal input alphabet is discrete, and has at most one mass point in each qu...

• Type: Conference
• Year: 2007
• Where: ICC
• Authors: Jaspreet Singh, Onkar Dabeer, Upamanyu Madhow
• Keywords: Bit Adc, Communications, Dithered Adc, ICC 2007, Tight Upper Bounds