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Ubiquitous Network BCN U biquitous S ensor N etwork 5
6 Ad-hoc network Sensing Read/Write Read Control
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/ 125KHz,134KHz 13.56Mhz 433.92MHz 860MHz~960MHz 2.45GMhz (ISO 18000-2) (ISO 18000-3) (ISO 18000-7) (ISO 18000-6) (ISO 18000-4), POST CARD / Invitation for Hitachi Exhibition 2002, Tire Pressure Sensor. Passport, ID card RFID chip 8
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Host Reader TAG APPLICATION COMMANDS APPLICATION RESPONSES Encoder Decoder Command/ Response Unit Tag Driver And Mapping Rules AIR INTERFACE COMMANDS RESPONSES Tag Physical Memory Logical Memory Map #ISO/IEC TR18001 (TR):ARP ARP Logical Memory Data Protocol Processor Physical Interrogator SG1 SG1 SG1 SG3 ISO/IEC 15961 ISO/IEC 15962 Host Interrogator Tag Data Syntax(CD) Functional Commands and Other syntax features(cd) ISO/IEC 15962 Annexes SG2 #ISO/IEC TR15963(FCD) Unique ID ISO/IEC 18000-1,2,3,4,6,7 1. Generic(FDIS) 2. Below 135kHz(FDIS) 4. 2.4GHz(FDIS) 6. 860-960MHz(FDIS) 3. 13.56MHz(FDIS) 7. 433MHz(FDIS) 1. : ISO/IEC JTC1/SC31/WG4 2. : NP CD FCD FDIS IS 11
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Standards and Projects EPCglobal 1 EPC Tag Data Specification SAG Version 1.24 Later slide EPCglobal 2 900 MHz Radio Frequency (RF) Identification Tag Specification (Class 0) Candidate recommendation EPCglobal 3 13.56 MHz ISM Band Class 1 Radio Frequency (RF) Identification Tag Interface Specification (Class 1) Candidate recommendation EPCglobal 4 860 MHz - 930 MHz Class I Radio Frequency (RF) Identification Tag Radio Frequency & Logical Communication Interface Specification (Class 1 Version 1) HAG Candidate recommendation EPCglobal 5 OID Radio Frequency Identity Protocols Generation 2 Identity Tag (Class 1): Protocol for Communications at 860 MHz 960 MHz (Generation 2) HAG EPCglobal 6 Reader Protocol SAG EPCglobal 7 Savant Specification SAG EPCglobal 8 Physical Markup Language (PML) Core Specification, XML Schema and Instance Files SAG EPCglobal 9 Object Name Service (ONS) Specification SAG Schedule Interim conference calls and webinars 27-28 May 2004 - HAG - Anaheim, CA 28 September - 1 October 2004 - Baltimore, MD: UHF Generation 2 15
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(Source: Auto-ID Center) 17
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Antenna Antenna 1 TAG 2 TAG Reader TAG 3 TAG (Modulated Reflection) 19
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Demodulator Voltage Multiplier Phase Modulator Clock Generator 21
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23 Application Layer Middleware Layer Reader Layer Telemetics Environment Alien Reader Legacy Systems ETRI Reader SD DATAX iz 9200 SDRD PORTA SD RD PORTB A ONLINE B BWD - ENTER PORTSEL DISC DATA + SD
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Reader #1 Channel #1 (f1) Reader #2 Channel #2 (f2)......... Reader #M Channel #N (fn) 26
Reader #1 Reader #2... Reader #M... Channel #1 (f1) Channel #2 (f2)... Channel #N (fn) Reader #1 Reader #2 Reader #M Reader Reader Reader 27
I When power matching (R T = R r ; R v =0; X T =X A ) P e = P S Only half of the power drawn from the antenna is transferred to the Load (R T ) The other half is reflected back into the space 28
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Slotted ALOHA procedure < Transponder system with slotted ALOHA anticollision procedure > 30
Transmit. TAG 1 TAG 2 TAG 3 TAG 4 TAG n Receiver If 40kbps 25usec * 64bit=1.6msec(data length) 250 Delay slot 400msec(same time) 31
Binary Search Algorithm 32
Binary Search Algorithm < Manchester code and NRZ code> 33
Binary Search Algorithm 34
Binary Search Algorithm 35
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Start Reader [PingID] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [EOF] [Bin modulation] 000 001 010 011 100 101 111... Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] Backscattering Backscattering Backscattering Contention Transaction gap Reader [PingID] [Bin modulation] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [EOF] 000 001 010 011 100 101 111... [PTR]=[0000 0000][LEN]=[0000 0011][VALUE]=[101] Contention Transaction gap Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] Backscattering Backscattering Reader [PingID] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [EOF] [Bin modulation] 000 001 010 011 100 101 111... [PTR]=[0000 0000][LEN]=[0000 0110] [VALUE]=[101001] Transaction gap Tag 1 Tag 2 Tag 3 [CRC][1010010010100100...] [CRC][1010011010100101...] [CRC][1110110011100111...] Backscattering Backscattering 37
Reader [ScrollID] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [CW... [PTR]=[0000 0000] [LEN]=[0000 1001][VALUE]=[101001001] Transaction gap Tag 1 [CRC][1010010010100100...] Tag 2 Tag 3 [CRC][1010011010100101...] [CRC][1110110011100111...] Backscattering Reader [Quiet] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [PTR]=[0000 0000][LEN]=[0000 1001] [VALUE]=[101001001] Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] No reply Reader [PingID] [Bin modulation] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [EOF] 000 001 010 011 100 101 111... [PTR]=[0000 0000] [LEN]=[0000 0000] [VALUE]=[0] Transaction gap Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] Backscattering Backscattering 38
Reader [ScrollID] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [CW... [PTR]=[0000 0000] [LEN]=[0000 0011] [VALUE]=[101] Transaction gap Tag 1 Tag 2 Tag 3 [CRC][1010010010100100...] [CRC][1010011010100101...] [CRC][1110110011100111...] Backscattering Reader [Quiet] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [PTR]=[0000 0000][LEN]=[0000 0011] [VALUE]=[101] Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] No reply Reader [PingID] [Bin modulation] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [EOF] 000 001 010 011 100 101 111... [PTR]=[0000 0000] [LEN]=[0000 0000] [VALUE]=[0] Transaction gap Tag 1 Tag 2 Tag 3 [CRC][1010010010100100...] [CRC][1010011010100101...] [CRC][1110110011100111...] Backscattering 39
Reader [ScrollID] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [CW... [PTR]=[0000 0000] [LEN]=[0000 0011][VALUE]=[111] Transaction gap Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] Backscattering Reader [Quiet] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] [PingID] [Preamble] [CLKSYNK] [SOF] [DATA] [EOF] END [PTR]=[0000 0000] [LEN]=[0000 0011] [VALUE]=[111] Tag 1 [CRC][1010010010100100...] Tag 2 [CRC][1010011010100101...] Tag 3 [CRC][1110110011100111...] No reply 40
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Comparison of Technologies for Flexible Electronics 43
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Sensors: device whose output can be quantified and changes with one or more physical phenomena. This output information can be used for process monitoring and control. Transducer: device which transforms energy from one domai n (magnetic, thermal, mechanical, optical, chemical, electrical) into another A detector: device indicating presence, absence, or change ofthe signal qualitatively, either as a binary signal or as a low resolution signal with several states. 45
Example of sensors Magnetic sensors Honeywell s HMC/HMR magnetometers Photo sensors Clairex: CL9P4L Temperature sensors Panasonic ERT-J1VR103J Accelerometers Analog Devices: ADXL202JE Motion sensors Advantaca s MIR sensors Properties of sensors Range Accuracy Repeatability Linearity Sensitivity Efficiency Resolution Response time Overshoot Drift and stability Offset Packaging Property of the circuit 46
We need to integrate the computation capa bility into the physical world to improve th e quality of life, and to facilitate applicatio ns that were not feasible before To make this possible, we need a large nu mber of computing devices. This mandates that they have very low cost and consume l ittle power For low-cost and low-power devices to do s ophisticated work, they need communicati on capability For a large number of devices to communi cate, radio communication is probably the only feasible option Finally, the current technology has enable d all these to happen To incorporate intelligence in the physical world Large number of computing devices Low-cost devices Wireless communication 47
Remote Sensing via Satellite Dataloggers Traffic Monitoring RFID Ad-hoc mobile networks Wireless Sensor Networks 48
RFID Tag with Sensor 49
Sensor Node Platform 50
Sensor Node Platform 51
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1. Why Sensor Networks? Small Processors (Size) Low cost Permits remote object monitoring Unattended mode of operation Coordination Deployed in toxic locations or remote regions Latest technology for Monitoring 54
2. Features of Sensor Networks What is a Sensor Network? 1000s of sensors deployed to collect, process and store information e.g. weather conditions. Local communication to achieve global objectives Current Ad-hoc protocols are not applicable Popular application areas Medical, Military, Natural Habitat monitoring, micro-organisms monitoring, etc Factors to consider when deploying sensors Low power Large numbers Frequent motion, task dynamics / Device failures Distributed sensing Exception free, unattended operation 55
3. Design Issues Sensor Network Vs Wired / Wireless network Data centric addressed by data values rather than identities Application Specific tailored for specific tasks Types of coordination between sensors to achieve above goals Centralized single point of failure energy inefficient non scalable Distributed localized algorithms robust to network partitions/ node failures short range of communication - energy efficient scalable low communication overhead simpler self-configuration 56
Sensor Node Considers issues like 4. Communication Architecture 57
4. Communication Architecture Considers issues like Hardware constraints Productions costs Environment Transmission media Current Ad-hoc protocols are not applicable 58
4. Communication Architecture Protocol Stack 59
5. Physical Layer Research Areas Modulation schemes Overcome effects of Signal propagation Hardware design Aim minimize energy Power d n, d= distance and 2<=n<=4. (n=4 for low lying antennas) M-ary reduces on-time by sending multiple bps Binary energy efficient - low complexity, low power consumption Suggested solution- Ultra wideband base-band transmission TDMA transmission resilience to multi-path Low transmission power simple transceiver circuitry. 60
Type Infrastructure Power Efficiency Goal Cellular Yes- Centralized Not power efficient Hi QoS/ bandwidth efficient Bluetooth No. Shortrange wireless Power 20dBm/ range 10m Replace cable between electronic terminals with RF links MANET Yes Not power efficient Hi QoS under mobility conditions Sensor N/w requires No Power~0dBm/ range<10m Power conservation 61
Research issues:- MAC for sensor networks Error control coding schemes Power saving modes Suggested MACs SMACS Self organizing MAC for sensor network Nodes discover neighbors, duplex time slots, random wake-up schedule and turn off in idle state EAR - Eaves-Drop-and-register algorithm (works with SMACS) Continuous service in mobile / stationary conditions CSMA-based MAC phase changes, constant listen periods and random delays. Hybrid TDMA/FDMA number of channels calculated for min. system energy 62
Design issues:- Power Efficient Data centricity Data Aggregation Attribute based addressing Internetworking with external networks Suggested Schemes Small Minimum Energy Communication Network (SMECN) Creates sub-graphs of sensor networks with minimum energy paths Flooding Broadcasting of data to all neighbors. Issue - resource blindness, Implosion 63
Gossiping Send data to randomly selected neighbors Sensor Protocols for Information via Negotiation Send data to only interested nodes. Send descriptive data rather than entire data. Sequential Assignment Routing Create multiple trees with roots are one hop away from sink. Nodes select a tree to route data back based on energy resources Low-Energy Adaptive Clustering Hierarchy Formation of clusters to conserve energy Directed Diffusion Data centric routing based on interests and gradients 64
Transport Layer Not explored much as yet. Option UDP for sink to sensors & TCP for sink to user * Proposed Solution for transport Application Layer Yet unexplored. 3 possible solutions:- - Sensor Management Protocol - Task Assignment and Data Advertisement Protocol - Sensor Query and Data Dissemination Protocol 65