42,767 research outputs found
Analytical characterisation of the terahertz in-vivo nano-network in the presence of interference based on TS-OOK communication scheme
The envisioned dense nano-network inside the human body at terahertz (THz) frequency suffers a communication performance degradation among nano-devices. The reason for this performance limitation is not only the path loss and molecular absorption noise, but also the presence of multi-user interference and the interference caused by utilising any communication scheme, such as time spread ON—OFF keying (TS-OOK). In this paper, an interference model utilising TS-OOK as a communication scheme of the THz communication channel inside the human body has been developed and the probability distribution of signal-to-interference-plus-noise ratio (SINR) for THz communication within different human tissues, such as blood, skin, and fat, has been analyzed and presented. In addition, this paper evaluates the performance degradation by investigating the mean values of SINR under different node densities in the area and the probabilities of transmitting pulses. It results in the conclusion that the interference restrains the achievable communication distance to approximate 1 mm, and more specific range depends on the particular transmission circumstance. Results presented in this paper also show that by controlling the pulse transmission probability and node density, the system performance can be ameliorated. In particular, SINR of in vivo THz communication between the deterministic targeted transmitter and the receiver with random interfering nodes in the medium improves about 10 dB, when the node density decreases one order. The SINR increases approximate 5 and 2 dB, when the pulse transmitting probability drops from 0.5 to 0.1 and 0.9 to 0.5
Mathematical modeling of ultra wideband in vivo radio channel
This paper proposes a novel mathematical model for an in vivo radio channel at ultra-wideband frequencies (3.1–10.6 GHz), which can be used as a reference model for in vivo channel response without performing intensive experiments or simulations. The statistics of error prediction between experimental and proposed model is RMSE = 5.29, which show the high accuracy of the proposed model. Also, the proposed model was applied to the blind data, and the statistics of error prediction is RMSE = 7.76, which also shows a reasonable accuracy of the model. This model will save the time and cost on simulations and experiments, and will help in designing an accurate link budget calculation for a future enhanced system for ultra-wideband body-centric wireless systems
Forward error correction for molecular communications
Communication between nanoscale devices is an area of considerable importance as it is essential that future devices be able to form nanonetworks and realise their full potential. Molecular communication is a method based on diffusion, inspired by biological systems and useful over transmission distances in the nm to μm range. The propagation of messenger molecules via diffusion implies that there is thus a probability that they can either arrive outside of their required time slot or ultimately, not arrive at all. Therefore, in this paper, the use of a error correcting codes is considered as a method of enhancing the performance of future nanonetworks. Using a simple block code, it is shown that it is possible to deliver a coding gain of ∼1.7 dB at transmission distances of . Nevertheless, energy is required for the coding and decoding and as such this paper also considers the code in this context. It is shown that these simple error correction codes can deliver a benefit in terms of energy usage for transmission distances of upwards of for receivers of a radius
Scalability of the channel capacity in graphene-enabled wireless communications to the nanoscale
Graphene is a promising material which has been proposed to build graphene plasmonic miniaturized antennas, or graphennas, which show excellent conditions for the propagation of Surface Plasmon Polariton (SPP) waves in the terahertz band. Due to their small size of just a few micrometers, graphennas allow the implementation of wireless communications among nanosystems, leading to a novel paradigm known as Graphene-enabled Wireless Communications (GWC). In this paper, an analytical framework is developed to evaluate how the channel capacity of a GWC system scales as its dimensions shrink. In particular, we study how the unique propagation of SPP waves in graphennas will impact the channel capacity. Next, we further compare these results with respect to the case when metallic antennas are used, in which these plasmonic effects do not appear. In addition, asymptotic expressions for the channel capacity are derived in the limit when the system dimensions tend to zero. In this scenario, necessary conditions to ensure the feasibility of GWC networks are found. Finally, using these conditions, new guidelines are derived to explore the scalability of various parameters, such as transmission range and transmitted power. These results may be helpful for designers of future GWC systems and networks.Peer ReviewedPostprint (author’s final draft
Impact of receiver reaction mechanisms on the performance of molecular communication networks
In a molecular communication network, transmitters and receivers communicate
by using signalling molecules. At the receivers, the signalling molecules
react, via a chain of chemical reactions, to produce output molecules. The
counts of output molecules over time is considered to be the output signal of
the receiver. This output signal is used to detect the presence of signalling
molecules at the receiver. The output signal is noisy due to the stochastic
nature of diffusion and chemical reactions. The aim of this paper is to
characterise the properties of the output signals for two types of receivers,
which are based on two different types of reaction mechanisms. We derive
analytical expressions for the mean, variance and frequency properties of these
two types of receivers. These expressions allow us to study the properties of
these two types of receivers. In addition, our model allows us to study the
effect of the diffusibility of the receiver membrane on the performance of the
receivers
Design and Optimizing of On-Chip Kinesin Substrates for Molecular Communication
Lab-on-chip devices and point-of-care diagnostic chip devices are composed of
many different components such as nanosensors that must be able to communicate
with other components within the device. Molecular communication is a promising
solution for on-chip communication. In particular, kinesin driven microtubule
(MT) motility is an effective means of transferring information particles from
one component to another. However, finding an optimal shape for these channels
can be challenging. In this paper we derive a mathematical optimization model
that can be used to find the optimal channel shape and dimensions for any
transmission period. We derive three specific models for the rectangular
channels, regular polygonal channels, and regular polygonal ring channels. We
show that the optimal channel shapes are the square-shaped channel for the
rectangular channel, and circular-shaped channel for the other classes of
shapes. Finally, we show that among all 2 dimensional shapes the optimal design
choice that maximizes information rate is the circular-shaped channel.Comment: accepted for publication in IEEE Transactions on Nanotechnolog
Amplify-and-Forward Relaying in Two-Hop Diffusion-Based Molecular Communication Networks
This paper studies a three-node network in which an intermediate
nano-transceiver, acting as a relay, is placed between a nano-transmitter and a
nano-receiver to improve the range of diffusion-based molecular communication.
Motivated by the relaying protocols used in traditional wireless communication
systems, we study amplify-and-forward (AF) relaying with fixed and variable
amplification factor for use in molecular communication systems. To this end,
we derive a closed-form expression for the expected end-to-end error
probability. Furthermore, we derive a closed-form expression for the optimal
amplification factor at the relay node for minimization of an approximation of
the expected error probability of the network. Our analytical and simulation
results show the potential of AF relaying to improve the overall performance of
nano-networks.Comment: 7 pages, 6 figures, 1 table. Submitted to the 2015 IEEE Global
Communications Conference (GLOBECOM) on April 15, 201
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