REFERENCES I.F. Akyildiz, F. Brunetti, and C. Blazquez, "NanoNetworking: A New Communication Paradigm", Computer Networks Journal, (Elsevier), June 2008. F. Akyildiz and J. M. Jornet, “Electromagnetic Wireless Nanosensor Networks”, Nano Communication Networks Journal (Elsevier), May 2010. 2 2

Nanotechnology Study of the control of matter on an atomic and molecular scale. Enabling the miniaturization and fabrication of devices in a scale ranging from one to a few hundreds nanometers 3

Nanotechnology Diameter of human hair 20-200 µm Typical cell diameter DNA double-helix diameter 2 nm Carbon atoms bond length 0.145 nm 4

NANOMATERIALS: GRAPHENE, NANOTUBES & NANORIBBONS Graphene: A one-atom-thick planar sheet of bonded carbon atoms in a honeycomb crystal lattice. * Carbon Nanotubes (CNT): A folded nano-ribbon (1991) * Graphene Nanoribbons (GNR): A thin strip of graphene (2004) 5

NANOMATERIALS: GRAPHENE, NANOTUBES & NANORIBBONS A graphene material sample used for testing its properties. Ten graphene nanoribbons between a pair of electrodes Courtesy of the Exploratory Nanoelectronics and Technology (ENT) Group, School of ECE, GaTech.

Nanomaterials: Graphene, Carbon Nanotubes & Nanoribbons Their electrical and optical properties, analyzed in light of Quantum Mechanics, offer: * High current capacity + High thermal conductivity  Energy efficiency * Extremely high mechanical strength  Robustness * Very high sensitivity (all atoms are exposed)  Sensing capabilities New opportunities for device-technology: Nano-batteries, nano-memories, nano-processors, nano-antennas, nano-tx, nano-rx.

Design of Nano-Devices 8

Design of Nano-Machines Bottom-Up Top-Down Bio-Hybrid Main Challenge: * Controlling the assembly process * Obtaining complex structures. Examples: * Molecular self-assembly * Molecular recognition. Main Challenge: Achieve molecular and atomic precision Examples: * Photolithography, * Micro-contact printing. Main Challenge: * Isolation of biological nano-machines * Hybridization. Examples: Bacteria transport 9

DESIGN OF NANO-MACHINES Nano-Material based Nano-Machines Biologically Inspired Nano-Machines 10

POWER UNIT (NANO-BATTERIES) Zinc Oxide Nano Wires Improved power density, lifetime, and charge/discharge rates. High density nano-wires used for nano-batteries.

NANO-PROCESSOR * 45 nm transistor technology is already on the market * 32 nm technology is around the corner * World’s smallest transistor (2008) is based on a thin strip of graphene just 1 atom x 10 atoms (1 nm transistor) World smallest transistor Courtesy of Mesoscopic Physics group at the University of Manchester. 12

Graphene EM Nano-Transmitter Signal Generator Modulator Power Amplifier Antenna Information Can we develop an EM transmitter in the nano-scale in light of molecular electronics? Yes, we can do that consistently with physics laws! It may take us some time !!

Graphene EM Nano-Receiver Demodulator LNA Antenna Information

NANO-MEMORY Graphene-based micro-scale memories offer high density storage systems (e.g., 64 Gbits/cm2) 15

NANO-ANTENNAS Graphene can also be used to build antennas: Using a single Carbon Nanotube (or a set of them): a nano-dipole Using a single Graphene Nanoribbon: a nano-patch Atom-precise antennas

Propose, model and analyze a novel nano-antenna A GRAPHENE-BASED NANO-ANTENNA J. M. Jornet and I.F. Akyildiz, “Graphene-based Nano-antennas for Electromagnetic Nanocommunications in the Terahertz Band”, in Proc. of 4th European Conference on Antennas and Propagation, (EUCAP), April 2010. Propose, model and analyze a novel nano-antenna design based on a metallic multi-conducting band Graphene Nanoribbon (GNR) and resembling a nano- patch antenna.

OUR CONTRIBUTIONS Developed a quantum mechanical framework to model the transmission line properties of GrapheneNanoRibbons: Contact resistance Quantum capacitance Kinetic inductance as a function of different design variables Ribbon dimensions System temperature System energy

WHAT DID WE LEARN? Graphene can be used to manufacture nano-antennas with atomic precision. Using nano-antennas, EM waves will be radiated in the Terahertz Band (0.1-10 THz): New opportunities for electromagnetic nano-scale communications New opportunities for Terahertz technology.

DESIGN OF NANO-MACHINES Nano-Material based Nano- Machines Biologically Inspired Nano-Machines 20 20

BIOLOGICAL NANO-MACHINES I.F. Akyildiz, F. Brunetti, and C. Blazquez, "NanoNetworking: A New Communication Paradigm", Computer Networks Journal, (Elsevier), June 2008. A CELL The most sophisticated existing nano-machine: Efficient energy consumption + Harvesting Mechanisms Multi-task computing + DNA processing Multi-sensing + Actuation

BIOLOGICAL NANO-MACHINES: POWER CELLULAR RESPIRATION Cell gains useful energy. By combining Glucose Amino Acids Fatty Acids Oxygen The cell obtains energy which is used to synthesize Adenosine TriPhosphate or ATP 22

HOW ABOUT AN ATP BATTERY? Mitochondria: a membrane enclosed organelle found in most eukaryotic cells. ** They generate most of the ATP per cell. ** Only present in eukaryotic cells.

BIOLOGICAL NANO-MACHINE: PROCESSOR/MEMORY Cells pose a good example of multi-tasking processors. In each cell, the “instructions” are contained in the genes, which are portions of DNA. Enzymes are bio-molecules that catalyze (trigger) the expression of a gene -> DNA processors.

BIOLOGICAL NANO-MACHINE PROCESSOR/MEMORY DNA: A nucleic acid that contains the instructions used in the development and functioning of all known living organisms. The manipulation of DNA or Hybridization will allow us to obtain user-defined biological Nano-machines

BIOLOGICAL NANO-MACHINE: TRANSCEIVER: EMISSION PROCESS A cell (the transmitter) synthesizes and releases in the medium molecules (proteins), as a result of the expression of a DNA sequence.

BIOLOGICAL NANO-MACHINE: RECEIVER: RECEPTION PROCESS Another cell (the receiver) captures those molecules and creates an internal chemical pathway that triggers the expression of other DNA sequences.

BIOLOGICAL NANO-MACHINE: RECEIVER: RECEPTION PROCESS

BIOLOGICAL NANO-MACHINE: RECEIVER: RECEPTION PROCESS Receptor-ligand binding: A ligand is a substance that is able to bind to and form a complex with a bio-molecule to serve a biological purpose A receptor is a protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell.

BIOLOGICAL NANO-MACHINE: PHEROMONE ANTENNA Ll. Parcerisa and I.F. Akyildiz, "Molecular Communication Options for Long Range Nanonetworks“, Computer Networks (Elsevier) Journal, Fall 2009. Pheromones are bigger molecules externally released by plants, insects and other animals that trigger specific behaviors among the receptor members of the same species.

Molecular Communication for Biological Nano-Networks NANO-COMMUNICATION PARADIGMS EM Based Communication for Nano-Material Based Nano-Networks Molecular Communication for Biological Nano-Networks 31

TERAHERTZ BAND FOR EM BASED NANO-NETWORKS J.M. Jornet and I.F. Akyildiz, “Channel Capacity of Electromagnetic Nanonetworks in the Terahertz Band”, in Proc. of IEEE ICC, Cape Town, South Africa, 2010. Developed an Attenuation and Noise model for EM communications in the Terahertz Band (0.1-10 THz) Uniqueness of the Terahertz band: * Terahertz channel is seriously affected by the presence of different molecules present in the medium * High molecular absorption attenuates the travelling wave and introduces noise into the channel

PATH-LOSS Determined by: Spreading Loss: accounts for the attenuation due to the expansion of the wave as it propagates through the medium. Absorption Loss: accounts for the attenuation due to molecular absorption.

SPREADING LOSS Depends on the frequency of the wave f and the total path length d: A dominant term in the total path loss computation !!

ABSORPTION LOSS Molecular composition of the channel: where τ is the transmittance of the medium and accounts for the molecular absorption of the channel; i.e., measures the amount of radiation that is able to pass through the medium. 35

MOLECULAR ABSORPTION Using Beer-Lambert law we obtain the transmittance of the medium τ as: where f is the wave frequency d is the path length P0 is the output power Pi isthe input power, and k is the medium absorption coefficient.

MOLECULAR ABSORPTION Medium absorption coefficient k depends on the particular mixture of particles found along the channel: where f is frequency ki,g is absorption coefficient of each isotopologue i of a gas g. e.g., Air in an office is mainly composed of * Nitrogen (78.1%) * Oxygen (20.9%) and * Water vapor (0.1-10%). 37

MOLECULAR ABSORPTION Absorption coefficient of a specific isotopologue i of a gas g where

MOLECULAR ABSORPTION For a given gas mixture, the volumetric water density can be obtained from the ideal gas laws equation as: where For example, with a 10% of water vapor, one molecule of H2O is found every 1 µm3

MOLECULAR ABSORPTION Absorption cross section can be further decomposed in * the absorption line intensity Si,g and * the absorption line shape Gi,g: Si,g depends on the type of molecules. We obtain this value from the HITRAN database. 40

MOLECULAR ABSORPTION The continuum absorption is obtained from Van Vleck-Weisskopf assymetric line shape where h is the Planck Constant c is the speed of light in vacuum kb ithe Boltzmann constant and αLi,g is the broadening coefficient. 41

NOISE The total noise at the receiver will be mainly contributed by: Electronic noise: predictably low due to large Mean Free Path of electrons in graphene, more accurate models are needed. Molecular noise: which also appears due to molecular absorption.

WHAT DID WE LEARN? * the transmission distance Terahertz communication channel has a strong dependence on * the transmission distance * medium molecular composition. Main factor affecting the performance of the Terahertz band  the presence of water vapor molecules. Terahertz frequency band offers incredibly huge bandwidths for short range (less than 1m) deployed nano-networks

Total Path Loss We can certainly not go further For the middle range, there are several windows TENTHS OF GIGAHERTZS WIDE. Can we exploit this? Maybe not nano… but micro? The almost absence of molecules in short distance does simplify everything in the short range.

MOLECULAR NOISE TEMPERATURE IN THE TERAHERTZ BAND NUMERICAL RESULTS MOLECULAR NOISE TEMPERATURE IN THE TERAHERTZ BAND

TERAHERTZ COMMUNICATIONS Some novel properties: Extreme large bandwidths The noise in the terahertz band is neither additive nor white.

RESEARCH CHALLENGES IN TERAHERTZ COMMUNICATIONS Accurate channel models accounting for molecular absorption, molecular noise, multi-path, etc. New communication techniques (e.g., sub-picosecond or femtosecond long pulses, multicarrier modulations, MIMO boosted with large integration of nano-antennas?). This band is still not regulated, we can contribute to the development of future communication standards in THz band.

RESEARCH CHALLENGES IN TERAHERTZ COMMUNICATIONS New information encoding techniques, definition of new codes tailored to the channel characteristics (time varying channel, non white noise). Frame and packet size, synchronization issues, transceivers architectures, etc. need to be defined. Network topology issues, network connectivity, network capacity, how are they affected by the channel?

RESEARCH CHALLENGES IN TERAHERTZ COMMUNICATIONS New MACs exploiting the properties of the THz band (e.g., collisions among femtosecond pulses may be negligible, OFDMA may be useful in such big bandwidths). New routing protocols and transport layer solutions for reliable transport in terahertz networks. Cross-layer solutions? What are the applications enabled by this huge bandwidth? 49

COMMUNICATION PARADIGMS FOR NANO-NETWORKS EM Based Communication for Nano-Machines Molecular Communication for Nano-Machines 50

A Possible Solution: Molecular Communication Defined as the transmission and reception of information encoded in molecules A new and interdisciplinary field that spans nano, ece, cs, bio, physics, chemistry, medicine, and information technologies 51

Nanonetworks vs Traditional Communication Networks Molecular Communication 52

Molecular Communication Short Range (nm to µm) Medium Range (µm to mm) Long Range (mm to m) Wired Wireless Wireless Wired Wireless Ion Signaling (e.g., calcium, sodium, potassium, chlorine) Pheromones Light transduction Pollen/Spores Molecular Motors Flagellated Bacteria Catalytic Nanomotors Axons Capillaries 53

Short-Range Communication Molecular Motors (Wired) Calcium Ions (Wireless) 54

Short-Range Communication using Molecular Motors What is a Molecular Motor? Is a protein or a protein complex that transforms chemical energy into mechanical work at a molecular scale Has the ability to move molecules 55

Short-Range Communication using Molecular Motors * Found in eukaryotic cells in living organisms * Molecular motors travel or move along molecular rails called microtubules * Movement created by molecular motors can be used to transport information molecules 56

Short-Range Communication using Molecular Motors 57

Short-Range Communication using Molecular Motors Encapsulation of information: Information can be encapsulated in vesicles. A vesicle is a fluid or an air-filled cavity that can store or digest cell products. 58

Short-Range Communication using Molecular Motors Encoding Transmission Propagation Reception Decoding Select the right molecules that represent information Attach the information packet to the molecular motor Information molecules are detached from molecular motors Receiver nano-machine invokes the desired reaction according to the received information Microtubules (molecular rails) restrict the movement to themselves 59

Short-Range Communication using Calcium Signaling Two Different Deployment Scenarios Direct Access Indirect Access Exchange of information among cells located next to each other Cells deployed separately without any physical contact 60

Short-Range Communication using Calcium Signaling Direct Access: Ca2+signal travel through gates 61

Short-Range Communication using Calcium Signaling Gap Junctions: Biological gates that allow different molecules and ions to pass freely between cells (membranes). 62

Short-Range Communication using Calcium Signaling Indirect Access: Transmitter nano-machine release information molecules to the the medium. Generate a Ca2+ at the receiver nano-machine. 63

Short-Range Communication using Calcium Signaling Encoding Transmission Signal Propagation Reception Decoding Information is encoded in Ca2+ Involves the signaling initiation Propagation of the Ca2+ waves Receiver perceives the Ca2+ concentration Receiver nano-machine reacts to the Ca2+ concentration 64 64

Problems of Short Range Molecular Communication Molecular Motors: Molecular motors velocity is 500 nm/s They detach of the microtubule and diffuse away when they have moved distances in the order of 1 µm Development of a proper network infrastructure of microtubules is required Molecular motors move in a unidirectional way through the microtubules  very long communication delays ! 65

Problems of Short Range Molecular Communication Calcium Signaling Very high delays for longer (more than few µm) distances 66

Medium Range Molecular Communication M. Gregori and I. F Medium Range Molecular Communication M. Gregori and I. F. Akyildiz, "A New NanoNetwork Architecture using Flagellated Bacteria and Catalytic Nanomotors," IEEE JSAC (Journal of Selected Areas in Communications), May 2010 Flagellated bacteria Catalytic nanomotors Pheromones Pollen & Spores Ion Signaling Molecular Motors 67

Medium Range Molecular Communication: Flagellated Bacteria Bacteria are microorganisms composed only by one prokaryotic cell. Flagellum allows them to convert chemical energy into motion. Escherichia coli (E. coli) has between 4 and 10 flagella, which are moved by rotary motors, fuelled by chemical compounds. E. coli bacteria is approximately 2 µm long and 1 µm in diameter. 68 68

Medium-Range Communication using Flagellated Bacteria Information is expressed as a set of DNA base pairs, the DNA packet, which is inserted in a plasmid. Encoding Transmission Propagation Reception Decoding DNA packet is introduced inside the bacteria’s cytoplasm, using: Plasmids Bacteriophages Bacterial Artificial Chromosomes (BACs) Bacteria sense gradients of attractant particles. They move towards the direction and finds more attractants (chemotaxis). The receiver releases attractants so the bacteria can reach it. DNA packet is extracted from the plasmid using: Restriction endonucleases enzymes 69 69

Why Bacterial Communication? Spans medium range to long range (μm to tens of cm) No need of infrastructure Better than molecular motors Reliable transfer of huge amount of information Up to 100Kbyte per bacteria (400K base pairs) using a plasmid.

Objective Analyze the communications aspects of flagellated bacteria-based information transport Delay and range And relation with other parameters (receiver size, bacteria speed, bacteria run period) How? Simulation!! Others: routing, coding

Why Simulation? Bacteria perform BIASED RANDOM WALK Moves more or less randomly, but tends to climb concentration gradients of attractants We simulate a bacteria that Starts swimming in a random direction Starts at given distance from spherical receptor of certain size Delay  time to reach the receptor Range  maximum distance

Simulation Model acterium RUNS or TUMBLES

Medium Range Molecular Communication: Catalytic Nanomotors (Nanorods) Au/Ni/Au/Ni/Pt striped nanorods are catalytic nanomotors, 1.3 µm long and 400 nm on diameter, can be externally directed by applying magnetic fields. We propose to use them as a carrier to transport the DNA information among nano-sensors 74 74

Medium-Range Communication using Catalytic Nanomotors Information is expressed as a set of DNA base pairs, the DNA packet, which is inserted in a plasmid. Encoding Transmission Propagation Reception Decoding Nanorods are introduced in a solution of AEDP AEDP binds with the Nickel segments DNA packets (plasmids) are attached to nanorods CaCl2 solution is used in order to compress and immobilize the plasmid Magnetic Fields guide the nanorod to the receiver DNA packet is extracted from the plasmid using: Restriction endonucleases enzymes 75 75

Long-Range Communication using Pheromones L. Parcerisa and I. F Long-Range Communication using Pheromones L. Parcerisa and I.F. Akyildiz, "Molecular Communication Options for Long Range Nanonetworks“, Computer Networks (Elsevier) Journal, Fall 2009 Features: Communication Range mm - m Medium Wet and dry Carrier Pheromones Pollen & Spores 76 76

Long-Range Communication using Pheromones Communication Features: 77 77

Long-Range Communication using Pheromones Encoding Transmission Signal Propagation Reception Decoding Pheremones are diffused into the medium Selection of the specific pheromones to transmit the information and produce the reaction at the intended receiver Releasing the pheromones through liquids or gases Pheremones bind to the Receptor Interpretation of the information (Different pheremones trigger different reactions) 78 78

Research Challenges in Nano-Networks Development of nano-machines, testbeds and simulation tools Information Theoretical Approach Architectures and Communication Protocols 79

MOLECULE DIFFUSION CHANNEL MODEL M. Pierobon, and I. F MOLECULE DIFFUSION CHANNEL MODEL M. Pierobon, and I. F. Akyildiz, ``A Physical Channel Model for Molecular Communication in Nanonetworks,’’ IEEE JSAC (Journal of Selected Areas in Communications), May 2010. Molecule Diffusion Communication: Exchange of information encoded in the concentration variations of molecules. RN TN Emission process Diffusion process Reception process 80

END-TO-END

Derivation of DELAY and ATTENUATION OBJECTIVE OF THE PHYSICAL CHANNEL MODEL Derivation of DELAY and ATTENUATION as functions of the frequency and the transmission range Non-linear attenuation with respect to the frequency Distortion due to delay dispersion 82

Transmitter MODELING CHALLENGES FOR THE PHYSICAL CHANNEL How chemical reactions allow the modulation of molecule concentrations as transmission signals ? Propagation How the “particle diffusion” controls the propagation of modulated concentrations ? Receiver How chemical reactions allow to sense the modulated molecule concentrations from the environment and translate them into received signals ? 83

Transmitter Model MOLECULE DIFFUSION CHANNEL MODEL Design of a chemical actuator scheme (chemical transmitting antenna) Analytical modeling of the chemical reactions involved in an actuator Signal to be transmitted  Modulated concentration 84

Propagation Model MOLECULE DIFFUSION CHANNEL MODEL Solution of the diffusion physical laws (FICK’s First and Second Laws (1855)) in the presence of an external concentration modulation Modulated concentration  Space-time concentration evolution 85

Receiver Model MOLECULE DIFFUSION CHANNEL MODEL Design of a chemical receptor scheme (chemical receiving antenna) Analytical modeling of the chemical reactions involved in a receptor Propagated modulated concentration  Received signal 86

Capacity Throughput FURTHER RESEARCH CHALLENGES FOR CHANNEL MODEL Noise Capacity Throughput 87

FINAL GOAL OF MOLECULAR COMMUNICATION RESEARCH Physical Channel Model How information is transmitted, propagated and received when a molecular carrier is used Noise Representation How can be physically and mathematically expressed the noise affected information transmitted through molecular communication Information Encoding/Decoding Concentration Chemical structure Encapsulation Molecular Channel Capacity 88