4,866 research outputs found
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
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
Channel Estimation for Diffusive MIMO Molecular Communications
In diffusion-based communication, as for molecular systems, the achievable
data rate is very low due to the slow nature of diffusion and the existence of
severe inter-symbol interference (ISI). Multiple-input multiple-output (MIMO)
technique can be used to improve the data rate. Knowledge of channel impulse
response (CIR) is essential for equalization and detection in MIMO systems.
This paper presents a training-based CIR estimation for diffusive MIMO (D-MIMO)
channels. Maximum likelihood and least-squares estimators are derived, and the
training sequences are designed to minimize the corresponding Cram\'er-Rao
bound. Sub-optimal estimators are compared to Cram\'er-Rao bound to validate
their performance.Comment: 5 pages, 5 figures, EuCNC 201
Detection Algorithms for Molecular MIMO
In this paper, we propose a novel design for molecular communication in which
both the transmitter and the receiver have, in a 3-dimensional environment,
multiple bulges (in RF communication this corresponds to antenna). The proposed
system consists of a fluid medium, information molecules, a transmitter, and a
receiver. We simulate the system with a one-shot signal to obtain the channel's
finite impulse response. We then incorporate this result within our
mathematical analysis to determine interference. Molecular communication has a
great need for low complexity, hence, the receiver may have incomplete
information regarding the system and the channel state. Thus, for the cases of
limited information set at the receiver, we propose three detection algorithms,
namely adaptive thresholding, practical zero forcing, and Genie-aided zero
forcing.Comment: 6 pages, 6 figures, 2015 IEEE ICC accepte
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