1,401 research outputs found
Optimal Detection for Diffusion-Based Molecular Timing Channels
This work studies optimal detection for communication over diffusion-based
molecular timing (DBMT) channels. The transmitter simultaneously releases
multiple information particles, where the information is encoded in the time of
release. The receiver decodes the transmitted information based on the random
time of arrival of the information particles, which is modeled as an additive
noise channel. For a DBMT channel without flow, this noise follows the L\'evy
distribution. Under this channel model, the maximum-likelihood (ML) detector is
derived and shown to have high computational complexity. It is also shown that
under ML detection, releasing multiple particles improves performance, while
for any additive channel with -stable noise where (such as
the DBMT channel), under linear processing at the receiver, releasing multiple
particles degrades performance relative to releasing a single particle. Hence,
a new low-complexity detector, which is based on the first arrival (FA) among
all the transmitted particles, is proposed. It is shown that for a small number
of released particles, the performance of the FA detector is very close to that
of the ML detector. On the other hand, error exponent analysis shows that the
performance of the two detectors differ when the number of released particles
is large.Comment: 16 pages, 9 figures. Submitted for publicatio
Zero-Error Capacity of a Class of Timing Channels
We analyze the problem of zero-error communication through timing channels
that can be interpreted as discrete-time queues with bounded waiting times. The
channel model includes the following assumptions: 1) Time is slotted, 2) at
most "particles" are sent in each time slot, 3) every particle is delayed
in the channel for a number of slots chosen randomly from the set , and 4) the particles are identical. It is shown that the
zero-error capacity of this channel is , where is the unique
positive real root of the polynomial .
Capacity-achieving codes are explicitly constructed, and a linear-time decoding
algorithm for these codes devised. In the particular case , ,
the capacity is equal to , where is
the golden ratio, and the constructed codes give another interpretation of the
Fibonacci sequence.Comment: 5 pages (double-column), 3 figures. v3: Section IV.1 from v2 is
replaced with Remark 1, and Section IV.2 is removed. Accepted for publication
in IEEE Transactions on Information Theor
A Survey on Modulation Techniques in Molecular Communication via Diffusion
This survey paper focuses on modulation aspects of molecular communication,
an emerging field focused on building biologically-inspired systems that embed
data within chemical signals. The primary challenges in designing these systems
are how to encode and modulate information onto chemical signals, and how to
design a receiver that can detect and decode the information from the corrupted
chemical signal observed at the destination. In this paper, we focus on
modulation design for molecular communication via diffusion systems. In these
systems, chemical signals are transported using diffusion, possibly assisted by
flow, from the transmitter to the receiver. This tutorial presents recent
advancements in modulation and demodulation schemes for molecular communication
via diffusion. We compare five different modulation types: concentration-based,
type-based, timing-based, spatial, and higher-order modulation techniques. The
end-to-end system designs for each modulation scheme are presented. In
addition, the key metrics used in the literature to evaluate the performance of
these techniques are also presented. Finally, we provide a numerical bit error
rate comparison of prominent modulation techniques using analytical models. We
close the tutorial with a discussion of key open issues and future research
directions for design of molecular communication via diffusion systems.Comment: Preprint of the accepted manuscript for publication in IEEE Surveys
and Tutorial
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