reception transmission propagation 2 MAXP’2009
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Molecular Multiple Access Molecular Broadcast Channel TN 2 TN 1 Molecular Relay Channel RN RN 1 TN H TN RN 1 RN 6 MAXP’2009 MP
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Physical Channel Model How information is transmitted, propagated and received when a molecular carrier is used Noise Representation Molecular How can be physically and mathematically expressed the Channel noise affecting information transmitted through molecular communication Capacity Information Encoding/Decoding Concentration Chemical structure Encapsulation 14 MAXP’2009 MP
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Particle Diffusion Communication exchange of information encoded in the concentration variations of particles Particles diffuse in a biological environment (cellular cytoplasm) Outcome: physical channel model normalized gain delay between two peer entities (TN and RN) 18 MAXP’2009
What type of information? Any continuous scalar signal How to encode information? Transmission signals will be encoded into particle concentration variations How to transmit? Transmitter should modulate particle concentration How information propagates? Through particle diffusion How to receive? Receiver should sense particle concentration translate into received signal 19 MAXP’2009
Molecule diffusion wireless communication: Transmitter: modulates molecule concentration Propagation: free diffusion of molecules Receiver: senses molecule concentration Transmitter Receiver 20 MAXP’2009
The transmitter is related to the Emission process, the propagation to the Diffusion process and the receiver to the Reception process TN RN Diffusion Reception Emission process process process 21 MAXP’2009
Release/capture of particles at the Positive rate modulation: transmitter location Box with inside molecule concentration and aperture to the outside The inside concentration is varied according outgoing particle flux to the signal to be transmitted Negative rate modulation: Particle outgoing/ingoing flux stimulated by inside-outside concentration gradient Emission modeled according to the laws of particle diffusion. ingoing particle flux 22 MAXP’2009
Particle emission model electrical parallel RC circuit Input current: signal to be transmitted Circuit voltage: particle inside-outside concentration gradient Resistor current: the particle concentration rate stimulated by the transmitter Resistance: inversely proportional to the diffusion constant Capacitance: unitary value 23 MAXP’2009
Diffusion process Process Process Atoms/ Process rate boundary equilibrium state molecules and evolution and starting mechanics conditions 24 MAXP’2009
Space Concentration rate signal propagation due to particle free diffusion in space Particle Emission (TN) Free particle diffusion governed by the diffusion laws The modulated concentration at transmitter location varies with respect to the other space locations Particle Reception (RN) Particles move within the space with the trend of homogenizing their concentration propagation of concentration rate signal Concentration Concentration at receiver at transmitter Emission modeled according to the relativistic laws of diffusion 25 MAXP’2009
Particle diffusion model Green’s function G of the laws of diffusion Non-relativistic diffusion (inhomogeneous Fick’s second law) Problem: allows superluminal propagation of information signals (modulated molecule concentration) Relativistic diffusion (Telegraph equation) Compliant with Special Relativity and Second Law of Thermodynamics 26 MAXP’2009
Non-relativistic Diffusion Relativistic Diffusion 27 MAXP’2009
Sensing of the particle concentration ligand+receptor complex (particle capture) at the receiver location N chemical receptors involved in capture/release ligand receptor The outside concentration varies and according to number of complexes stimulates complex formation/breaking complex ligand+receptor (particle release) The particle receiver modulates the output Reception modeled according to the complex ligand-receptor binding process 28 MAXP’2009
Particle Reception model electrical series RC circuit Input voltage: molecule concentration to receiver Circuit current: particle inside-outside concentration gradient Resistor current: the molecule concentration rate sensed by the receiver Resistance: inversely proportional to the ligand-receptor binding/release rates Capacitance: number of receptors 29 MAXP’2009
Model parameters: Range: from 0 micron to 50 micron biological environment, cellular cytoplasm) Frequency spectrum: from 0 to 1KHz Diffusion coefficient: D = 10^-6 m^2/sec (calcium molecules diffusing in a Relativistic relaxation time: water molecules = 10^9sec. Ligand binding/release rates: assumed to be 10^8 1/(M sec) Number of receptors: from 20 to 100 The curves related to higher values of the transmitter-receiver distance show lower values of normalized gain throughout the frequency spectrum range. For every curve, each frequency is delayed by a different time the shape of the channel output signal is distorted with respect to the channel input signal (more pronounced for higher values of the transmitter-receiver distance) 30 MAXP’2009
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Build a new information theory through the study of: Noise Capacity Throughput Study a Molecular Communication system: Max SNR max throughput How to minimize delay 34 MAXP’2009
Diffusion Process Nano (isotropic?) mac Chemical change affects Bw 1 (isotropic?) Nano mac Brownian motion 3 (isotropic?) Nano Diffusion Process mac (isotropic?) 2 affects Bw Information mixing (receiver signal processing / Turbulence adaptive filtering?) (anisotropic?) same molecule as 35 MAXP’2009 MP
Extinction latency Nano Cross-symbol mac interference 1 Symbol Info Nano mac 0110 3 0111 Nano mac 2 Symbol usage desynchronizing 36 MAXP’2009 MP
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