  The wide bandwidth and large number of antennas used in millimeter wave
systems put a heavy burden on the power consumption at the receiver. In this
paper, using an additive quantization noise model, the effect of analog-digital
conversion (ADC) resolution and bandwidth on the achievable rate is
investigated for a multi-antenna system under a receiver power constraint. Two
receiver architectures, analog and digital combining, are compared in terms of
performance. Results demonstrate that: (i) For both analog and digital
combining, there is a maximum bandwidth beyond which the achievable rate
decreases; (ii) Depending on the operating regime of the system, analog
combiner may have higher rate but digital combining uses less bandwidth when
only ADC power consumption is considered, (iii) digital combining may have
higher rate when power consumption of all the components in the receiver
front-end are taken into account.
