presented by:
S.MOHANAPRIYA

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The channel delivers the message through variations on the molecule concentration at the receiver location.
THE MOLECULAR RECEIVER
The receiver is involved with capture or release of molecules
A number of chemical receptors are used to receive information
It is modeled according to the chemical theory of the ligand-receptor binding process.
when the receptor is not bound to a molecule , binding process occurs
The release reaction occurs when there is a complex formation by a molecule
When a chemical receptor is bound to a molecule, it produces constant signal as output
The sum of all the receptor outputs provides the receiver the total molecule concentration.
Finally, the receiver decodes the message from
the molecule concentration rate.
End-to-end Communication Parameters
The normalized gain is computed by multiplying the normalized gain contributions coming from transmitter to receiver.
The delay is obtained by summation of the delay contributions coming from the transmitter to molecular receiver.
PROPAGATION MODEL FOR NEC
For NEC the antennas ranging from few hundred nanometres require high operating frequencies.
But this can be overcome by the graphene and nanoribbons
Graphene and carbon nanotubes resonate in the terahertz band (0.1 - 10.0 THz).
The future NEC network works in terahertz band and this has to be characterised in the nanoscale
The existing terahertz channel models are aimed to characterize the communication between devices that are several meters far.
PATH LOSS
The path loss in terahertz band is the addition of
spreading loss and
the molecular absorption loss
SPREADING LOSS
It is the attenuation due to the expansion of the wave as it propagates through the medium.
It depends only on the signal frequency and the transmission distance
THE ABSORPTION LOSS 
Attenuation occurs because of molecular absorption.
wave energy is converted into internal kinetic energy
This depends on the concentration and the particular mixture of molecules encountered along the path.
Different types of molecules have different frequencies
Hence the absorption loss is spread over a range of frequencies.
As a result, the terahertz channel is very frequency-selective
The total path-loss increases
Because of the spreading loss,
Non uniform concentration of molecules
Due to the bursting of the molecules
NOISE
The noise is mainly contributed by the molecules.
The absorption from molecules present in the medium also introduces noise.
Noise at the receiver will be determined by the number and the particular mixture of molecules found along the path.
The noise is neither gaussian nor white.
The power spectral density of noise is not flat, but has several peaks.
This type of noise will only appear when transmitting
No noise exists when the channel is left free
BANDWIDTH AND CHANNEL CAPACITY
Bandwidth ranges from giga to terahertz .
Depends on the molecular composition of the channel and the transmission distance.
As a result, the channel capacity is very large
Additional channel effects
The additional channel effects include
multi-path propagation
Multiple copies of transmitted signals
nanoparticle scattering
molecules and other particles
CHALLENGES IN MC
Theoretical approach to be implemented to study the
noise mutual information capacity and throughput.
Suitable modulation and coding schemes should be derived.
This will enable a wide range of applications
CHALLENGES IN EMC
New propagation models for the nanoscale terahertz channel need to incorporated
Accounting multi-path effects and nanoparticle scattering.
The interaction of terahertz radiation has to be envisaged.
There is a need to develop new information encoding and modulation techniques.
By the exchange of sub picoseconds long pulses, nano-devices will be able to achieve very high transmission rates