28 research outputs found
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 Ī¼m 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 ā¼1.7 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
Adaptive Molecule Transmission Rate for Diffusion Based Molecular Communication
In this paper, a simple memory limited transmitter for molecular
communication is proposed, in which information is encoded in the diffusion
rate of the molecules. Taking advantage of memory, the proposed transmitter
reduces the ISI problem by properly adjusting its diffusion rate. The error
probability of the proposed scheme is derived and the result is compared with
the lower bound on error probability of the optimum transmitter. It is shown
that the performance of introduced transmitter is near optimal (under certain
simplifications). Simplicity is the key feature of the presented communication
system: the transmitter follows a simple rule, the receiver is a simple
threshold decoder and only one type of molecule is used to convey the
information
Minimum energy channel codes for molecular communications
Owing to the limitations of molecular nanomachines, it is essential to develop reliable, yet energy-efficient communication techniques. Two error correction coding techniques are compared under a diffusive molecular communication mechanism, namely, Hamming codes and minimum energy codes (MECs). MECs, which previously have not been investigated in a diffusive channel, maintain the desired code distance to keep reliability while minimising energy. Results show that MECs outperform the Hamming codes, both in aspects of bit error rate and energy consumption
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
Nanoparticle communications : from chemical signals in nature to wireless sensor networks
The need to convey information has always existed in both the animal and human kingdoms. The article offers a review of the latest developments in transporting information using nanosized particles. It begins by examining chemical signalling in nature, and goes on to discuss recent advances in mimicking this in bio-inspired engineering. It then points out the important difference between signalling and general communication, and explains why the latter is a more challenging problem. The existing research on mimicking chemical signalling in nature is a precurser to research into general chemical communication. A review of the latest theoretical research in general chemical communications is presented, along with the practical developments of the worldās first nanoparticle communications test-bed. In the parts of the article, the authors discuss the potential research challenges and identify three important areas for future development: robustness, miniaturization, and scalability
Low-complexity non-coherent signal detection for nano-scale molecular communications
Nano-scale molecular communication is a viable way of exchanging information between nano-machines. In this letter, a low-complexity and non-coherent signal detection technique is proposed to mitigate the intersymbol-interference (ISI) and additive noise. In contrast to existing coherent detection methods of high complexity, the proposed non-coherent signal detector is more practical when the channel conditions are hard to acquire accurately or hidden from the receiver. The proposed scheme employs the concentration difference to detect the ISI corrupted signals and we demonstrate that it can suppress the ISI effectively. The concentration difference is a stable characteristic, irrespective of the diffusion channel conditions. In terms of complexity, by excluding matrix operations or likelihood calculations, the new detection scheme is particularly suitable for nano-scale molecular communication systems with a small energy budget or limited computation resource