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Wireless communication using local area networking


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  • 1. Wireless Communication Using Local Area Networking Lalithkrishnan H Lokesh kumar B Keywords: Human area network, Red tacton, Blue tooth, Intra-body tacton, Infrared, Electro-optic sensor, Laser.Abstract: The major problem in today’s communication systems such as Blue tooth andworld is communication. Even though the wireless local area networks. Throughput is reduceddigital communication has evolved, it is by packet collisions. In crowded spaces such asstill not efficient for all the people to meeting rooms and auditoriums filled withaccess and also the infrared people , Communication is not securecommunication has some serious because signals can be intercepted.The ultimatedisadvantages .To overcome this a newer human area network solution to all these constraintscommunication method, which uses of conventional technologies is “intrepid”conduction property of human body to communication, in which the human bodytransmit signals called as red tacton is serves as the transmission medium. In everydayproposed in this paper. RedTacton is services, if we could use the human body itself as aa new Human Area Networking transmission medium, then this would be an idealtechnology that uses the surface of the way of implementing human area networkshuman body as a safe, high-speed because it would solve at a stroke all thenetwork transmission path. Red tacton problems throughput reduction, low security, anduses the very weak electric field emitted high network setup costs.on the surface of the human body. Atransmission path is formed Red tactonautomatically by body contact and this Red Tacton involves initiatinginitiates communication between action with a touch that could result in a wideelectronic devices. range of actions in response. So, NTT Combined touch and action to coin the term Tacton, and thenIntroduction added the word Red - a Warm color -- to Today people can emphasize warm and cordial communications,communicate any time, anywhere, and with creating the name RedTacton. RedTacton operatesanyone over a cellular phone network. on the idea that optical properties of an electro-opticMoreover, the Internet lets people crystal can vary according to the changes of a persondownload immense quantities of data from own electric field. After contract with anotherremotely located servers to their home RedTacton enabled device, the transmitter one wearscomputers. Essentially, these two induces an electric field on the body. Next, thetechnologies enable communications transceiver on the device detects changes in thebetween terminals located at a distance wearers electric field which was caused by thefrom each other. Short-range wireless device. The devices then communicate and send
  • 2. data by inducing fluctuations in the electricfield of the human body. Data is receivedusing a photonic electric field sensor thatcombines an electro-optic crystal and a laserlight to detect fluctuations in the minuteRedTacton works through shoes andclothing as well. fingers, arms, feet, face,legs or toes. using any body surfaces, suchas the hands,legs.etc.PRINCIPLE: The principle of initiates the flow of data For example, twoRedTacton is illustrated in Fig. 2.The weak people equipped with RedTacton deviceselectric fields pass through the body to a could exchange data just by shaking hands.RedTacton receiver, where the weak electricfields affects the optical properties of anelectro-optic crystal. The extent to which theoptical properties are changed is detected bylaser light, which is then converted to anelectrical signal by a detector circuit.Earepresents the electric field induced towardthe body by the transmitter’s signalelectrode. The system requires a groundclose to the transmitter signal electrode, soelectric field is induced from the body canfollow a return path to the transmitterground. Moreover, since people are usuallystanding on a floor or the ground, electricfield Es escapes from the body to ground,mainly from the feet.. Theelectric field Es that reaches the receiver is (2) Using a RedTacton electro-optic sensor,Es = Ea – (Eb + Ec) to be initiated two-way communication is supportedthrough natural actions such as between any two points on the body at agrasping, sitting walking and stepping throughput of up to 10 Mbps.onto something. Electrical sensors basically Communication is not just confined to theinvolve two-wire communication with a surface of the bodysignal line and a ground line, so when (3) RedTacton can utilize a wide range ofthere is only a signal line a(i.e., the human materials as a transmission medium, as longbody) ,the signal cannot be transmitted as the material is conductive and dielectric,properly. which includes water and other liquids, various metals, certain plastics, glass, etc.The three major functional features of Using ordinary structures such as tables andRedTacton are highlighted below. walls that are familiar and readily available, one could easily construct a seamless(1) A communications path can be created communication environment at very low cost with simple Touch, automatically using RedTacton [Fig 4].
  • 3. The propagation used here is similarPROPAGATION INSIDE THE HUMAN to that of nerve impulse. Neurons sendBODY messages electrochemically; this means that chemicals (ions) cause an electrical impulse. Neurons and muscle cells are electrically excitable cells, which means that they can transmit electrical nerve impulses. These impulses are due to events in the cell membrane. In nerve and muscle cells the membranes are electrically excitable, which means they can change their membrane potential, and this is the basis of the nerve impulse. The sodium and potassium channels in these cells are voltage-gated, which means that they can open and close depending on the voltage across the membrane. The normal membrane potential inside the axon of nerve cells is –70mV, and since this potential can change in nerve cells it is called the resting
  • 4. vibration. Pacinian corpuscles are also located in joints and tendons and in tissue that lines organs and blood vessels. Pressure on the skin changed the shape of the Pacinian corpuscle. This changes the shape of the pressure sensitive sodium channels in the membrane, making them open. Sodium ions diffuse in through the channels leading to depolarisation called a generator potential. The greater the pressure the more sodium channels open and the larger the generator potential. If a threshold value is reached, an action potential occurs and nerve impulses travel along thepotential. When a stimulus is applied a brief sensory neurone. The frequency of thereversal of the membrane potential, lasting impulse is related to the intensity of theabout a millisecond, occurs. This brief stimulus.once the potential is created a currentreversal is called the action potential: is induced this current is the characteristic of signal transmitted.the amount of deformation is The Pacinian Corpuscle characteristic of organ not the potential.based on the changes it is fed to optical crystal receiver for Pacinian corpuscles are pressure processing.receptors. They are located in the skin andalso in various internal organs. Each is RED TACTON TRANCEIVERconnected to a sensory neuron. Pacinian fig. 3 shows a photograph of the RedTactoncorpuscles are fast-conducting, bulb-shaped transceiver connected to a PDA and a blockreceptors located deep in the dermis. They diagram of the Red Tacton transceiver developed by NTT. The transmitterconsist of the ending of a single neurone consists of a transmitter circuit that inducessurrounded by lamellae. They are the largest electric fields toward the body and a data sense circuit, which distinguishesof the skins receptors and are believed to transmitting and receiving modes byprovide instant information about how and detecting both transmission and reception data and outputs control signalswhere we move. They are also sensitive to corresponding to the two modes to enable
  • 5. two-way communication. The receiverconsists of an electro-optic sensor anda detector circuit that amplifies theminute incoming signal from the electro-optic sensor and converts it to electricalsignal.. We quantitatively measured the biterror rates of signals sent through the body.ANALYSIS The results showed that thesystem had no significant practical problemsat a transmission speed of 10 Mbit/s. Besidescommunications between two hands, we alsodemonstrated reliable communicationbetween a foot and finger and betweenother locations on the person’s body.We also verified that good communicationwas achieved not only when the electrodeswere in direct contact with the person’s APPLICATIONSskin, but also when the signals passedthrough clothing and shoes. Information recorded in the RedTacton device is sent to the touched objects. Thereby, the following applications are inhibited. (1)Personalization (1.1) Personalization of mobile phones, (1.2) Personalization of Automobiles (2) New Behavior patterns (2.1) Conferencing system (3) Security Applications (3.1) User verification and lock management at entrance. It forms a replacement for biometric systems and also the alternative FIG 4 for a secured world
  • 6. DESIGN ARCHITECTURE The design architecture for our prototype system is illustrated, which exploits wideband signaling (WBS) for the digital audio streaming over the human body. Its architecture consists of five parts: physical medium, interface layer, signaling link layer, transceiver module, and application. The human body as the physical medium shows a wide band-pass operational spectrum and sustains the channel capacity sufficient to Fig 5 transfer real-time multimedia data streams as investigated in [2]. The electrical signal can Just by touching the lock be flowed by the feeble electric field inducedTrans-receiver circuit gets activated to on the skin of the body. The interface layerenable other biometric system to recognize provides the connection with the physicalindividual. medium. After the connection is established, (3.2)Confidential document management the digital audio data transfers to the(4) Mobile computation wearable I/O devices over a WBS link. (4.1) Can connect a single phone Transceiver module performs the packet with several other phones via blue generation of the streaming data and supports tooth using this principle. the WBS link that enables a point-to-point transfer or broadcasting between each application layer. REALIZATION The prototype system is realized by using the WBS transceiver chip developed of [2]. The system hardware excluding the transceiver chip consists of off-chip components: 24-bit analog-to-digital Fig 6 converter (ADC) and digital-to-analog converter (DAC), digital audio interface (4.2) Without any blue tooth device, transmitter and receiver as shown in Figure 8. just by touching a device you could The S/PDIF standard is chosen for the digital can hear sounds. audio interface. The analog audiosignals for two stereo channels are sampled by the 24-bit sigma-delta ADC. The 24-bit sampled audio data is converted to a 32-bit packet consisting of a 4-bit preamble, the 24-bit data, and a 4- bit channel status and error detection bits. Subsequently, the data is transmitted with biphase-mark encoding at twice of the bit rate, which allows clock recovery from the data at the receiver. The effective data rate is Fig 7 2.048-Mb/s at the sampling rate of 16-kHz
  • 7. over the channel. The audio sound is played claims to be able to send data over the humanback by the 24-bit DAC. No audio decoder skin surface at transfer speeds of up tois required at the earset. Thus, it leads to the 10Mbps, or better than a broadband T1reduction of the cost and the power connection. Receiving data in such a systemconsumption. The transceiver chip controls is more complicated because the strength ofthe WBS link for the transmission of digital the pulses sent through the electric field is soaudio data. The 0.25-0.5m CMOS WBS low. Red Tacton solves this issue by utilizingtransceiver chip including a receiver AFE a technique called electric field photonics: Aconsumes only 5-mW from a 1-V supply. laser is passed though an electro-opticCompared with a Bluetooth transceiver [3], it crystal, which deflects light differentlyexhibits lower power consumption at high according to the strength of the field across rate. Figure 3 (b) shows the photo of the These deflections are measured andprototype system consisting of a WBS audio converted back into electrical signals totransmitter connected to a MP3 player and a retrieve the transmitted data.WBS audio receiver assembled into an earset.The transmitter attaches to the back of the It has some limitations:audio player.The Rx electrode is mounted onthe hanger of the earset. 1) The operating range through the body was Limited to a few tens of centimeters and 2) The top communication speed is only 40 K bits/s. These limitations arise from the use Of an electrical sensor for the receiver. An Electrical sensor requires two lines (a signal Line and a ground line), whereas in intra- body communication there is essentially only one Signal line, i.e., the body itself, which leads to an unbalanced transmission line, so the signal is not transmitted correctly. 3)if we want to get a information form a device then that device should be equipped with red tacton transmitter .this process is Fig 8 costlier and time consuming. Block diagram of wireless MP3 player CONCLUSION: In a busy place there couldADVANTAGE OVER BLUETOOTH be hundreds of Bluetooth devices within range.Chances are more for the information The system envisioned by to be trakked. Using this transceiver, weNTT, utilizes a conversion method which succeeded in achieving 10 BASEtakes digital data into a stream of low-power communications through a human body fromdigital pulses. These can be easily transmitted one hand to the other hand. While ourand read back through the human electric immediate objective is to implement a Redfield. While it is true that similar personal Tacton system supporting two-way intraarea networks are already accessible by using body communication at a rate of 10 M bitsradio-based technologies like Wi-Fi or between any two points on the body, ourBluetooth, this new wireless technology
  • 8. longer-term plans include developing amass-market transceiver interface supportingPDA’s s and notebook computers. Thus thisproblem has been solved by the red tactonand has made it very innovative.REFERENCES(1) T. G. Zimmerman, “Personal AreaNetworks: Near-field intrabodycommunication,” IBM Systems Journal, Vol.35, Nos. 3&4, pp. 609-617, 1996. (2) M. Shinagawa, “Development of Electro-optic Sensors for Intra-bodyCommunication,” NTT Technical Review,Vol. 2, No. 2, pp. 6-11,2004.(3) 4) M. Mizoguchi, T. Okimura, and A.Matsuda, “ComprehensiveCommercializationFunctions,” NTT Technical Review, Vol. 3,No. 5, pp.