3 research outputs found
Diversity gain of one-shot communication over molecular timing channels
We study diversity in one-shot communication over molecular timing channels.
In the considered channel model the transmitter simultaneously releases a large
number of information particles, where the information is encoded in the time
of release. The receiver decodes the information based on the random time of
arrival of the information particles. We characterize the asymptotic
exponential decrease rate of the probability of error as a function of the
number of released particles. We denote this quantity as the system diversity
gain, as it depends both on the number of particles transmitted as well as the
receiver detection method. Three types of detectors are considered: the
maximumlikelihood (ML) detector, a linear detector, and a detector that is
based on the first arrival (FA) among all the transmitted particles. We show
that for random propagation characterized by right-sided unimodal densities
with zero mode, the FA detector is equivalent to the ML detector, and
significantly outperforms the linear detector. Moreover, even for densities
with positive mode, the diversity gain achieved by the FA detector is very
close to that achieved by the ML detector and much higher than the gain
achieved by the linear detector.Comment: To be presented at GLOBECOM 201
A Novel Time-Based Modulation Scheme in Time-Asynchronous Channels for Molecular Communications
In this paper, a novel time-based modulation scheme is proposed in the
time-asynchronous channel for diffusion-based molecular communication systems
with drift. Based on this modulation scheme, we demonstrate that the sample
variance of information molecules' arrival time approximately follows a
noncentral chi-squared distribution. According to its conditional probability
density function (PDF), the asynchronous receiver designs are deduced based on
the maximum likelihood (ML) detection, with or without background noise in the
channel environment. Since the proposed schemes can be applied to the case of
transmitting multiple information molecules, simulation results reveal that the
bit error ratio (BER) performance improves with the increase of the number of
released information molecules. Furthermore, when the background noise is not
negligible, our proposed asynchronous scheme outperforms the asynchronous
modulation techniques based on encoding information on the time between two
consecutive release of information molecules.Comment: 11 pages, 10 figure
Exploiting Diversity in Molecular Timing Channels via Order Statistics
We study diversity in one-shot communication over molecular timing channels.
We consider a channel model where the transmitter simultaneously releases a
large number of information particles, while the information is encoded in the
time of release. The receiver decodes the information based on the random time
of arrival of the information particles. The random propagation is
characterized by the general class of right-sided unimodal densities. We
characterize the asymptotic exponential decrease rate of the probability of
error as a function of the number of released particles, and denote this
quantity as the system diversity gain. Four types of detectors are considered:
the maximum-likelihood (ML) detector, a linear detector, a detector that is
based on the first arrival (FA) among all the transmitted particles, and a
detector based on the last arrival (LA). When the density characterizing the
random propagation is supported over a large interval, we show that the simple
FA detector achieves a diversity gain very close to that of the ML detector. On
the other hand, when the density characterizing the random propagation is
supported over a small interval, we show that the simple LA detector achieves a
diversity gain very close to that of the ML detector.Comment: Submitted for publication; 10 pages; 5 figure