30 research outputs found
Capacity of a Simple Intercellular Signal Transduction Channel
We model the ligand-receptor molecular communication channel with a
discrete-time Markov model, and show how to obtain the capacity of this
channel. We show that the capacity-achieving input distribution is iid;
further, unusually for a channel with memory, we show that feedback does not
increase the capacity of this channel.Comment: 5 pages, 1 figure. To appear in the 2013 IEEE International Symposium
on Information Theor
Bounds on the Capacity of ASK Molecular Communication Channels with ISI
There are now several works on the use of the additive inverse Gaussian noise
(AIGN) model for the random transit time in molecular communication~(MC)
channels. The randomness invariably causes inter-symbol interference (ISI) in
MC, an issue largely ignored or simplified. In this paper we derive an upper
bound and two lower bounds for MC based on amplitude shift keying (ASK) in
presence of ISI. The Blahut-Arimoto algorithm~(BAA) is modified to find the
input distribution of transmitted symbols to maximize the lower bounds. Our
results show that over wide parameter values the bounds are close.Comment: 7 pages, 4 figures, Accepted in IEEE GLOBECOM 201
Molecular communication in fluid media: The additive inverse Gaussian noise channel
We consider molecular communication, with information conveyed in the time of
release of molecules. The main contribution of this paper is the development of
a theoretical foundation for such a communication system. Specifically, we
develop the additive inverse Gaussian (IG) noise channel model: a channel in
which the information is corrupted by noise with an inverse Gaussian
distribution. We show that such a channel model is appropriate for molecular
communication in fluid media - when propagation between transmitter and
receiver is governed by Brownian motion and when there is positive drift from
transmitter to receiver. Taking advantage of the available literature on the IG
distribution, upper and lower bounds on channel capacity are developed, and a
maximum likelihood receiver is derived. Theory and simulation results are
presented which show that such a channel does not have a single quality measure
analogous to signal-to-noise ratio in the AWGN channel. It is also shown that
the use of multiple molecules leads to reduced error rate in a manner akin to
diversity order in wireless communications. Finally, we discuss some open
problems in molecular communications that arise from the IG system model.Comment: 28 pages, 8 figures. Submitted to IEEE Transactions on Information
Theory. Corrects minor typos in the first versio
Molecular Communication Using Brownian Motion with Drift
Inspired by biological communication systems, molecular communication has
been proposed as a viable scheme to communicate between nano-sized devices
separated by a very short distance. Here, molecules are released by the
transmitter into the medium, which are then sensed by the receiver. This paper
develops a preliminary version of such a communication system focusing on the
release of either one or two molecules into a fluid medium with drift. We
analyze the mutual information between transmitter and the receiver when
information is encoded in the time of release of the molecule. Simplifying
assumptions are required in order to calculate the mutual information, and
theoretical results are provided to show that these calculations are upper
bounds on the true mutual information. Furthermore, optimized degree
distributions are provided, which suggest transmission strategies for a variety
of drift velocities.Comment: 20 pages, 7 figures, Accepted for publication in IEEE Trans. on
NanoBioscienc
Information Rates of ASK-Based Molecular Communication in Fluid Media
This paper studies the capacity of molecular communications in fluid media,
where the information is encoded in the number of transmitted molecules in a
time-slot (amplitude shift keying). The propagation of molecules is governed by
random Brownian motion and the communication is in general subject to
inter-symbol interference (ISI). We first consider the case where ISI is
negligible and analyze the capacity and the capacity per unit cost of the
resulting discrete memoryless molecular channel and the effect of possible
practical constraints, such as limitations on peak and/or average number of
transmitted molecules per transmission. In the case with a constrained peak
molecular emission, we show that as the time-slot duration increases, the input
distribution achieving the capacity per channel use transitions from binary
inputs to a discrete uniform distribution. In this paper, we also analyze the
impact of ISI. Crucially, we account for the correlation that ISI induces
between channel output symbols. We derive an upper bound and two lower bounds
on the capacity in this setting. Using the input distribution obtained by an
extended Blahut-Arimoto algorithm, we maximize the lower bounds. Our results
show that, over a wide range of parameter values, the bounds are close.Comment: 31 pages, 8 figures, Accepted for publication on IEEE Transactions on
Molecular, Biological, and Multi-Scale Communication