Sharif Digital Repository

Molecular communication (MC), which utilizes molecules as its carriers of information, is one of the oldest mechanisms among micro-organisms on earth. In recent years, using MC for communication among nanomachines has attracted enormous interest because of its simplicity and bio-compatibility. Diffusion-based MC mechanism is one of the most important communication mechanisms, which has wide applications because of no needs for energy and prior infrastructure. The important challenges in MC systems include node complexity, inter-symbol interference (ISI), and co-channel interference (CCI). Due to the small sizes of the nodes in MC, complexity is a serious issue. Because nanomachines are... 

In this thesis, a simple memory limited transmitter for molecular communication is proposed, in which information is encoded in the emission rate of the molecules. Taking advantage of memory, the proposed transmitter reduces the ISI problem by properly adjusting its emission rate, which can be interpreted as water-filling on the expected interference. The error probability of the proposed scheme is derived and the result is compared with the error probability of the optimal transmitter obtained by dynamic programming methods. Further, for the special case of channel with one symbol memory, a tight lower bound on error probability is derived. Numerical results show that the performance of... 

This thesis studies on diffusion-based molecular communication channel between two nano-machines. The effect of the amount of memory on performance is characterized, and a simple memory-limited decoder is proposed and its performance is shown to be close to that of the best possible decoder (without any restrictions on the computational complexity or its functional form), using Genie-aided upper bounds. This effect is studied for the case of Molecular Concentration Shift Keying; it is shown that a four-bits memory achieves nearly the same performance as infinite memory. Then a general class of threshold decoders is considered and shown not to be optimal for a Poisson channel with memory,... 

Molecular communication is a new paradigm in communication science, which studies opportunities and challenges of information transmission in nanoscale. Unlike the classical communication, which uses electro-magnetic waves as signal carriers, in this new method of communication, tiny agents in molecular scale are the main information barriers. In this sense, studying molecular communication requires theoretical development and updating some well-known techniques of classical communications.Although there have been some successful attempts to implement communication systems based on molecular communication, the field is still in the theoretical development phase. In this thesis, we have tried... 

In recent years, molecular communications have received considerable attentions for communication between nano-machines. In this communication scheme, which uses molecules as information carriers, nano transmitter and receiver are in distance apart of nano meter to meter and information is encoded into type, concentration or releasing time of molecules. Since nano transmitter and receiver can do very simple operations, such as adding, sensing, and etc., for more complicated operations, a network of nano transceivers is required. In this thesis, a small scale imaging of an abnormality in the environment is investigated. To this end, a network of sensors is assumed to be placed in the... 

Molecular communication (MC), is a new way of communication among nanomachines.its applications are typically in cases which the conditions of transfer such as size, nature of the medium and nature or type of the original signal, is consistent with molecules such as medicine, health care, industrial and environmental applications.In this thesis, we first review different models of molecular transmitters. In most of them, storage capacity and molecule generation rate are not considered. we try to propose practical transmitter models considering these limitations. for high storage capacity transmitters, we propose Fixed and Linear transmission methods. assuming that channel is without... 

Molecular communication which is inspired by nature has emerged as a promising field in recent years for its potential applications in medicine, environment, tissue engineering, industry and so on. In molecular communication, molecules are the information carriers. One of the mechanisms of movement of molecules that does not require any infrastructure is Diffusion. Diffusion-based molecular communication in which molecules diffuse in the medium in order to reach the receiver, has two major problems: delayed and lost molecules. Due to the randomness of diffusion, molecules are usually received with varied delays, their order of reception is different from the order of transmission and even... 

Today communication systems use electromagnetic signals for data transmission. However there are applications, in which the use of these signals is impossible or inefficient. For example in underwater communication, because of salinity of water, electromagnetic signals attenuate very fast. Regarding to this, inspired by nature, molecular communication systems is introduced, which use molecules as carriers of information for transmission of data. One of the main challenges in molecular communication in diffusion medium is that most of these channels suffer from low information capacity. With this respect, this thesis studies the channel capacity of diffusion based molecular channels by... 

Molecular communication (MC), which has stimulated a great deal of interest in recent years, is a new paradigm for communication among nanoscale biological machines. In MC, molecules are carriers of information and information is encoded into concentration, type or releasing time of molecules. One of the issues in MC is to consider a network consisting of multiple nano-sensors or living cells, which intend to communicate with each other.In this thesis, we first consider multiple-access networks in MC. In multiple-access networks, multiple sender nano-machines intend to communicate with a receiver nano-machine through a common medium. We consider the receiver with ligandreceptors and... 

Molecular communication (MC), which has stimulated a great deal of interest in recent years, is a new paradigm for communication among nanoscale biological machines. In MC, molecules are carriers of information and information is encoded into concentration, type or releasing time of molecules. One of the issues in the problem of finding more explicit bounds on the capacity.An approach for bounding mutual information in the low SNR regime using the symmetrized KL divergence is introduced and its applicability to Poisson channels is shown. To the best of our knowledge, the first upper bound on the capacity of Poisson channel with a maximum transmission constraint in the low SNR regime is... 

Recently, the nano-bio communication networks have received significant attention. Among different communication mechanisms proposed for nano communication, diffusion based molecular communication (DMC) is the most promising scheme. This thesis focuses on DMC and first proposes a theoretical model for this scheme. In the next part of the thesis, inspired by the molecule transport mechanisms in the biological cells, two biosynthetic modulator structures are proposed.In first structure, an ion channel based modulator for DMC is proposed which controls the rate of molecule release from the transmitter by modulating a gating parameter signal. The corresponding average modulated signal, i.e., the... 

The progress in the design of nano-scale machines over the past decade has motivated researchers to study the concept of nano-communications. Inspired by biological systems,diffusion-based molecular communication (MC) systems have been proposed as a potential solution for communication in nano-networks where molecules are used as information carriers.Nano-networks are envisioned to facilitate revolutionary applications in areas such as biological engineering, healthcare, and environmental monitoring. In recent years, there has been a significant amount of work on various aspects of MC systems, including transmitter and receiver design, multiple access protocols, and network layer issues....