Type based estimation over multiaccess channels

Abstract

Abstract-We study the problem of communicating sensor readings over a Gaussian multiaccess channel. We focus on the scenario that each sensor observes a single random variable and transmits it using certain signaling in a shared channel. The objective is the design of channel waveforms (i.e., the signal constellation) to facilitate the estimation of field parameters from the channel output. We propose a communication scheme in which sensors transmit according to the type of their observations-type-based multiple access (TBMA)-and show that the TBMA is asymptotically optimal in the limit of large number of sensors if the sensor channelgains are identical. In particular, we show that TBMA together with a variant of the maximum-likelihood estimator achieves the Cramer-Rao bound asymptotically. We then extend the asymptotic analysis of TBMA to fading channels and compare the performance of TBMA with other orthogonal allocation methods such as time-division multiple access.

Parameter Estimation Over Noisy Communication Channels in Distributed Sensor Networks

“…Such multiple access communication (MAC) in bandwidth constrained wireless sensor networks has been investigated in, among others, [10], [11], [17], [24], [25], [34], [36], [44]. For example, in [24], [25], [44] the authors proposed a type based multiple-access communication in which sensors transmit according to the type of their observation in a shared channel where the type is as defined in [45]. An analysis of both orthogonal and MAC channels for distributed detection in a sensor network was presented in [44].…”

A Likelihood-Based Multiple Access for Estimation in Sensor Networks

“…Once the problem is discretized (that is, we are dealing with random variables with a finite number of possible outcomes) the type-based multiple access (TBMA) approach can be exploited. The TBMA is introduced and studied in [14]- [16]; a relevant feature is that TBMA asymptotically reaches the Cramér-Rao bound for quantized observations. In our paper, we will find conditions that allow achieving the Cramér-Rao pertaining to the original, unquantized data.…”

Distributed Estimation over Unknown Fading Channels

“…For the third scheme, each node is assigned a signaling waveform (or code) generally assumed to be orthogonal, equi-correlated and perfectly correlated with a perfect synchronization in sensor transmissions, Wimalajeewa and Jayaweera (2007). In the literature, other MAC protocols have been proposed; that is the case of Type based MAC, Mergen and Tong (2006), and likelihood-based MAC, Marano et al (2007), both devoted to fusion center based WSNs.…”