Cramer-Rao bounds for rate-constrained distributed time-delay estimation

This paper investigates time-delay estimation for acoustic source localization in a distributed microphone array. The microphones are assumed to be part of a wireless sensor network, with a constraint on the number of bits that may be exchanged between the sensors. Consequently, at the fusion center, time-delay estimation needs to be performed using quantized signals. In this paper, the relation between the communication bit-rate and the Cramer-Rao lower bound (CRLB) on the variance of the time-delay estimation error is explored. The minimum bit-rate required to ensure that the CRLB is attained is also derived.