무선센서네트워크의기술동향 2008. 03. 13 Wireless Information and Network Engineering Research Lab. Ajou University, Korea
Contents USN 개념및소개 RFID 기술및응용 센서네트워크장점및응용 USN 플랫폼구성요소및역할 USN 기술및요구사항 무선센서네트워크표준 결론 참고문헌 USN 개요 -I 2
USN 개념및소개 USN 개요 -I 3
USN 개념및소개 USN (Ubiquitous Sensor Network) 이란? Infrastructure network for realizing ubiquitous computing environment using sensor nodes with sensing, processing and wireless communication capabilities 모든사물에전자태그부착사물정보및환경정보까지감지네트워크에연결하여실시간관리 Ubiquitousq Sensor Network 동물관리 물류 / 유통 : SCM, 재고관리쇼핑센터 : 자동계산대 홈네트워크병원환자관리 USN 교통 : 텔레매틱스 ITS 시스템교통요금 환경 : 공해감시 ( 자연 ) 재해관리 USN 개요 -I 4
RFID 기술및응용 USN 개요 -I 5
RFID 기술및응용 RFID (Radio frequency Identification) 이란? RFID is a simple form of ubiquitous sensor networks that are used to identify physical objects Remote identification Non-line-of-sight Automatic reading Tag RF Channel Reader Local Server Network * RF Radio Frequency USN 개요 -I 6
RFID 기술및응용 RFID 주파수및응용분야 ID card Name: Rei Itsuki No.: 00012345 Div.: Mu VC Company: Hitachi, Ltd. POST CARD Invitation for Hitachi Exhibition 2002 Embedded μ-chip Passport, ID card Global 125KHz,134KHz (ISO 18000-2) 13.56Mhz (ISO 18000-3) 433.92MHz (ISO 18000-7) 860MHz 960MHz (ISO 18000-6) 2.45GMhz (ISO 18000-4) USN 개요 -I 7
Chiplesss Passive Chip Semi-Activee Chip Active Chip RFID 기술및응용 자료출처 : ID TechEx RFID 기술별가격전망 $100 $50 $10 $1 30c 10c 5c 1c 이상 USN 개요 -I 8
RFID 기술및응용 RFID 가격별적용분야및특성 태그가격대 분야이용목적기능특성 10 만원정도 군사 의료 군용품 의료기기 위치측정 진단기능 보안 1 만원정도 교통 ( 요금지불, 차량주행증 주행중요금지불도난방지, 보험등 ) 자동요금지불 인증, 보안 1 천 ~5 천원 출입통제 유통 ( 컨테이너, 파렛트 ) 출입통제 컨테이너, 파렛트, 가축등의추적 보안 100~1000 원 항공, 세탁물 가구, 미술품 물품관리 고속읽기, 쓰기 위조방지 50 원 제조 ( 공장 ), 목재 자산관리 위조방지 소매 ( 고가품목 ) 제품, 목재등의추적 추적 10 원정도 소매 ( 저가품목 ) 교통 ( 티켓 ) 소매품관리및추적 교통기관의티켓추적 저가격, 저기능 추적기능 자료출처 : IDTechEx USN 개요 -I 9
RFID 기술및응용 RFID 기술발전전망 구분 2004 년 고속화, 소형화, 저가화 2005년 2006년 2007년 ~2010년 네트워크화, 초소형화, 초저가화 지능화 저전력 CMOS 칩 NANO, MEMS 초소형칩폴리머칩 태그 / 칩 코일-콘덴서회로 표면탄성파재질이용회로 프린팅안테나 / 패키징 칩내장형안테나 패키지안테나 코드읽기전용태그센서통합다기능태그자율통신태그 리더네트워크연동 단일대역빔성형안테나 /RF 기술 다중대역, 광대역안테나 /SDR 기술 고속다중인식 : 100 Tag/ 초 200 Tag/ 초 300 Tag/ 초 리더 / 인터넷연동 이동통신망 / 휴대인터넷연동 4G/BCN 연동 텔레매틱스, 홈네트워크연동 서비스 업무자동화 장거리다중물품인식 고가물품관리 물품정보인식 / 추적 환경감지정보이용 / 관리 / 추적 사물위치측정 / 추적 생활용품인식 / 관리 사물간자율통신 USN 개요 -I 10
RFID 기술및응용 Multi-tag anti-collision algorithm in RFID Arbitration Air Interface (R->T / T->R) EPC Data rate (R->T / T->R) ISO 18000-6 Framed Pulse interval ASK / not 33 kbps / TYPE A Slotted FM0 defined 40 kbps ISO 18000-6 Probabilistic Manchester-ASK / not 8/40 kbps / TYPE B Binary tree FM0 defined 40 kbps AutoID Bit-by-bit Pulse Width Mod./ 40/80 kbps / 64/96b Class 0 Binary Tree FSK 40/80 kbps Security None None 24-bit kill AutoID Class 1 Binary tree using 8 bin slots Pulse Width Mod. / Pulse Interval AM 64/96b 70.18 kbps/ 140.35 kbps 8-bit kill EPCglobal Gen 2 Probabilistic Slotted Pulse interval ASK / Miller, FM0 96/496b 40 kbps / 640 kbps 32-bit kill, Access USN 개요 -I 11
센서네트워크장점및응용 USN 개요 -I 12
센서네트워크장점및응용 Sensor Network Applications Building Automation Personal Health Care Industrial Control Telecom Services Home Control Consumer Electronics PC & Peripherals INDUSTRIAL CONTROL PERSONAL HEALTH CARE TELECOM SERVICES BUILDING AUTOMATION HOME CONTROL CONSUMER ELECTRONICS PC & PERIPHERALS USN 개요 -I 13
센서네트워크장점및응용 Sensor Network Applications Building Automation Security, HVAC, AMR, lighting control, and access control Personal Health Care Patient monitoring and fitness monitoring Industrial Control Asset management, Process control, and energy management Telecom Services m-commerce, info services, and object interaction Home Control Security, HVAC, lighting control, access control, and irrigation Consumer Electronics TV, VCR, DVD/CD, and remote PC & Peripherals Mouse, keyboard, and joystick USN 개요 -I 14
센서네트워크장점및응용 Characteristics of USN Large number of sensor nodes Maybe 10 to 100,000 nodes (scalability) Node position may not be predetermined Low cost Low energy consumption To relocate & recharge large number of nodes is impossible Life time of sensor network depends on battery life time Network self-organization Large number of nodes in hostile locations Manual configuration unfeasible Nodes may fail & new nodes join the network Ad-hoc sensor network protocols Collaborative/Distributed processing Locally carry out simple computation -> forwards and aggregate data Query ability (Sensor Database) Single node or group of nodes Base nodes collect data from given area & create summary messages USN 개요 -I 15
센서네트워크장점및응용 USN and Ad-hoc Network Comparison Items for comparison Sensor Network Ad-hoc Network Number of nodes 100 ~ 1000 10 ~ 100 Deployment Densely Relatively sparsely Failure Prone to failure Not prone to failure Communication Broadcast Point-to-point Topology change Very frequent Almost steady Power Limited Rechargeable Resource Limited Relatively high ID Local ID Global ID(IP address) * Source APNOMS 2005 Tutorial, Okinawa, Japan USN 개요 -I 16
USN 플랫폼구성요소및역할 USN 개요 -I 17
USN 플랫폼구성요소및역할 USN Protocol Stack Coordinating to minimize duty cycle and communication Adaptive topology, routing, and adaptive MAC In-network processing Data centric routing and programming models Logical Function of layers Application Transport Network Data link User Queries, External Database Application Processing, Aggregation, Query Processing Adaptive topology, Geo-Routing MAC, Time, Location, Adaptive Physical Communication, Sensing, Actuation ti USN 개요 -I 18
USN 플랫폼구성요소및역할 USN Protocol Stack Physical Layer Needs Simple, but robust modulation, transmission, and receiving technique Transmission media Radio Infrared ISM (Industrial, Scientific, Medical) 915MHz band widely suggested Optical media Open research issues Modulation scheme Need simple and low-power modulation scheme Hardware design Tiny, low-power, low-cost Power-efficient hardware management strategy USN 개요 -I 19
USN 플랫폼구성요소및역할 USN Protocol Stack Data Link Layer Responsible for multiplexing of data streams, Medium Access control (MAC) and Error Control Medium Access Control (MAC) Creation of the network infrastructure Fairly and efficiently communication resources sharing between sensor nodes MAC for Sensor Network SMACS (Self-Organizing Medium Access Control for Sensor Networks) EAR (Eaves-drop-And-Register) Algorithm CSMA-Based MAC scheme Hybrid TDMA/FDMA-Based MAC scheme Power Saving Modes of Operation Error Control FEC (Forward Error Correction) ARQ (Automatic Repeat Request) USN 개요 -I 20
USN 플랫폼구성요소및역할 USN Protocol Stack Network Layer Needs Data Routing Requirement Power efficiency, Data-centric, Data aggregation Sh Scheme Description Flooding Gossiping LEACH SPIN Directed diffusion Power Efficiency Routing Smecn SAR Broadcasts data to all neighbor nodes Sends data to one randomly selected neighbor Forms a cluster to minimize energy loss Sends data to sensor nodes only if they are interested, has 3 types of messages (ADV, REQ, DATA) Sets up gradients for date to flow from source to sink during interest disseminition Pick a route based on : Max. Power Available(PA), min Energy (ME),, Min Hop(MH), or Max Min PA Create a sub-graph of the sensor network that contains the minimum energy path Creates multiple trees where the root of each tree is one hop neighbor from the sink USN 개요 -I 21
USN 플랫폼구성요소및역할 USN Protocol Stack Transport Layer Needs Research Naming Maintain the flow of data if the sensor networks applications requires it Communication between user and sink node TCP or UDP via the internet or satellite Communication between sink node and sensor node UDP type protocol, because sensor node has limited memory Not based on global addressing Attribute-based naming USN 개요 -I 22
USN 플랫폼구성요소및역할 USN Protocol Stack Application Layer Needs Depending on the sensing tasks, different types of application software built and used Application layer protocols SMP (Sensor Management Protocol) System administrators i interact with sensor networks using SMP TADAP (Task Assignment and Data Advertisement Protocol) SQDDP (Sensor Query and Data Dissemination Protocol) USN 개요 -I 23
USN 기술및요구사항 - Location Technology in USN - Time Synchronization in USN - USN Management - USN Management Requirement - USN Management Goal - USN Management Architecture - USN Management Functional Area USN 개요 -I 24
Location Technology in USN Discovery of absolute or relative location Geographical routing (location attribute based naming and addressing) Tracking of moving objects Context (location) aware applications Challenges in USN Energy constraint Harsh environment with multi-paths Minimal infrastructure (Few beacons, No backend computation) Many techniques for location sensing TOA (Time Of Arrival) TDOA (Time Difference Of Arrival) AOA (Angle Of Arrival) SSR (Signal Strength Ranging) GPS, etc. USN 개요 -I 25
Time Synchronization in USN Critical at many layers of sensor network Communication, localization, distributed DSP, etc. Conventional approaches GPS Indoors?, cost, size, energy NTP (Network Time Protocol) Delay and jitters due to MAC and store-and-forward relaying Discovery of timer servers (nodes synchronize with one of a pre-specified list of time servers) Reference-broadcast synchronization (RBS) Very high precision sync. with slow radios Beacons are transmitted, using physical-layer broadcast, to a set of receivers Time synchronization is based on the difference between reception times, do not sync sender with receivers USN 개요 -I 26
USN Management Why isn t SNMP (Simple Network Management Protocol) adaptable to USN? Sensor-specific failures are not handled Difficult to find the failed nodes Physical connections are not utilized Commonly, there is not a management agent Specifying nodes is difficult Network is self-configured, so that management server doesn t have all information of sensor nodes Challenges Present many and drastically different challenges. For example: Deployment of nodes, Discarding of nodes Require augmentation to (or new approaches over) traditional network and service management techniques Need to take into account specific characteristics of WSNs (e.g., energy waste) USN 개요 -I 27
USN Management Requirements Fault tolerance Handle loss of nodes - Lack of Power, Physical damage, Environmental interference Scalability Handle high density of nodes - The number of sensor nodes is an extreme value of millions Production costs Make them low cost - Cost of a single node is very important to justify the overall cost of the network Operating environment Survive and maintain communication - The bottom of an ocean, biologically contaminated field, battlefield Transmission media Wireless - Radio, infrared, optical media Hardware constraints Nodes are tiny - Very small size, very light node, limited memory, limited battery Power consumption Limited Tx, computation, lifetime - Replenishment of power is impossible Changing Topology Nodes - Nodes moving, new nodes, loss nodes USN 개요 -I 28
USN Management Goal Promote resources productivity Maintain the quality of the services provided Application-dependent and the management solution design is affected USN Applications Affect USN Management Design Developing management solutions for USN Not trivial Become worse due to the physical restrictions of sensor nodes Energy, bandwidth, Significantly different with the management of traditional networks USN 개요 -I 29
USN Management Architecture USN 개요 -I 30
USN Management Functional Areas Functions Fault Configuration Accounting Performance Security - Faults in USNs are not an exception and tend to occur frequently, thus fault management is a critical function - This is one of the reasons that make USN management different from traditional network management - Slfdi Self-diagnostic : the network monitors itself and find faulty or unavailable nodes - Self-healing : the network prevents disruptions or that acts to recover itself or the node after the self-diagnostic - Self-organization : is the property which the sensor nodes must have to organize themselves to form the network - Self-configuration : nodes setup and network boot up must occur automatically -It includes functions related to the use of resources and corresponding reports -It establishes metrics, quotas and limits that can be used by functions of other functional areas -It must provide self-sustaining functionalities - There is a trade-off to be considered : the higher the number of managed parameters, the higher the energy consumption and the lower the network lifetime - On the other hand, if enough parameter values are not obtained, it may not be possible to manage the network appropriately - Security functionalities for USNs are intrinsically difficult to be provided because of their adhoc organization, intermittent connectivity, wireless communication and resource limitations - A USN is subject to different safety threats : internal, external, accidental, and malicious USN 개요 -I 31
무선센서네트워크표준 - IEEE 802.15.4 - ZigBee overview USN 개요 -I 32
무선센서네트워크표준 IEEE 802 Wireless Space Range WWAN WMAN WLAN WPAN IEEE 802.22 IEEE 802.20 WiMax IEEE 802.16 WiFi ZigBee 802.11 802.15.4 Bluetooth 802.15.3 15.4c 802.15.1 802.15.3c 0.01 0.1 1 10 100 1000 Data Rate (Mbps) USN 개요 -I 33
무선센서네트워크표준 IEEE 802.15.4 overview Low Cost, Power, and Rate (20, 40, 250Kbps) Short Range (less than 10m) Dynamic device addressing Support for low latency devices Reliable by fully handshake protocol CSMA-CA channel access. Low power consumption Apply to u-smart Home Network : Energy save, Consumer Electronics, Toy, Security Health care check and monitoring i System Topology Star or peer-to-peer p topology USN 개요 -I 34
무선센서네트워크표준 IEEE 15.4 PHY Channel 0 2MHz Channel 1-10 Channel 11-26 5MHz 868MHz 902MHz 928MHz 24GHz 2.4GHz 2.4835GHz Frequency 868MHz 915MHz 2.4GHz Data Rate 20kbps 40kbps 250kbps Modulation BPSK BPSK O-QPSK # of Channel 1 10 (2MHz) 16 (5MHz) Packet period 53.2ms 26.6ms 4.25ms Receiver sensitivity < -92dBm < -92dBm < -85dBm Range 10~20m(1mW) 10~20m(1mW) 10~20m(1mW) USN 개요 -I 35
무선센서네트워크표준 MAC overview Features of the MAC sub-layer Beacon management Channel access Guaranteed time slot management Frame validation Acknowledged frame delivery Association and disassociation Security mechanisms FFD (Full Function Device) A device capable of operating as a coordinator or device, implementing the complete protocol set. RFD (Reduced Function Device) A device operating with a minimal implementation of the IEEE 802.15.4 protocol. Can not be a coordinator device USN 개요 -I 36
무선센서네트워크표준 802.15.4 MAC/PHY Frame Format octet 2 1 4-20 n 102 2 Frame Sequence Address control number info Payload FCS MAC octet 3.75~50.625~2.5 1 MHR MSDU MAF Preamble SFD FL MAC Protocol Data Unit (MPDU) SHR PHR Physical Service Data Unit (PSDU) PHY Physical Protocol Data Unit (PSDU) PPDU size : 13.5 + ( 4 to 20) + n ( 135.5 Octet) - FCS : Frame Check Sequence - MHR : MAC Header - MSDU : MAC Service Data Unit - MAF : MAC Footer - FL : Frame Length - SFD : Start Frame Delimiter - SHR : Synchronization Header - PHR : Physical Header - PPDU : Physical Protocol Data Unit USN 개요 -I 37
무선센서네트워크표준 IEEE 802.15.4 Operational Modes IEEE 802.15.4 MAC Beacon Enabled Non Beacon Enabled Superframe Unslotted CSMA/CA Contention Access Period (Without GTS) Contention Access/ Contention Free Periods (With GTS) Slotted CSMA/CA Slotted CSMA/CA / Slot Allocations USN 개요 -I 38
무선센서네트워크표준 IEEE 802.15.4 Superframe Structure USN 개요 -I 39 39
무선센서네트워크표준 IEEE 802.15.4 Superframe Structure The superframe structure without GTSs Frame Beacon Contention Access Period Inactive Period The superframe structure with GTSs Frame Beacon Contention Access Period Contention Free Period Inactive Period USN 개요 -I 40
CSMA/CA protocol Use different Inter Frame Space (IFS) to differentiate traffic SIFS (Short Inter Frame Space) : High Priority PIFS (PCF Inter Frame Space) : Medium Priority DIFS (DCF Inter Frame Space) : Low Priority Sense channel during DIFS DIFS DIFS PIFS Contention Window SIFS Busy Medium Backoff-Window Next Frame Slot time Defer Access Backoff slot reduced when channel is idle USN 개요 -I 41
CSMA/CA protocol Exponential Back-off Algorithm CW : Contention Window ( 0 to CW_min ~ CW_max ) : Backoff delay = int(cw * Random()) * Slot Time Slot time : Receiver turn on time + propagation delay + media busy detection time CW_min : 11.a = 15, 11.b = 7, 11.b HR = 31, CW_max = 1023 CW is doubled when transmission is failed Example 300 CW_max=255 255 250 200 150 127 100 50 CW_min =7 31 63 0 1 2 3 4 5 6 USN 개요 -I 42
CSMA/CA protocol CSMA/CA with ACK Defer access based on Carrier Sense CCA from PHY and Virtual Carrier Sense state Direct access when medium is sensed free longer than DIFS, otherwise df defer and dbackoff kff Receiver of directed frames to return an ACK immediately when CRC correct When no ACK received, then retransmit the frame after a random backoff (up to a maximum limit) USN 개요 -I 43
CSMA/CA protocol Hidden Node Problem While STA-A sends data to STA-B STA-C may try to communicate with STA-B Resulting in the collision in STA-B STA-A don t know whether there is STA-C or not Use RTS-CTS dialogue to resolve Hidden Node Problem Collision STA-A STA-B STA-C USN 개요 -I 44
CSMA/CA protocol CSMA/CA with RTS-CTS USN 개요 -I 45
CSMA/CA protocol Exposed Node Problem By RTS-CTS dialogue F A B C D E RTS RTS CTS CTS DATA DATA ACK ACK Reserved area USN 개요 -I 46
ZigBee Overview USN 개요 -I 47
Basic Network Characteristics 65,536 network (client) nodes 27 channels over 2 bands 250Kbps data rate Optimized i dfor timing-critical i iti applications and power management Full Mesh Networking Support Network coordinator Full Function node Reduced Function node Communications flow Virtual links USN 개요 -I 48
Basic Radio Characteristics ZigBee technology relies upon IEEE 802.15.4, which has excellent performance in low SNR environments USN 개요 -I 49
ZigBee Mesh Networking USN 개요 -I 50
ZigBee Mesh Networking USN 개요 -I 51
ZigBee Mesh Networking USN 개요 -I 52
ZigBee Mesh Networking USN 개요 -I 53
ZigBee Mesh Networking USN 개요 -I 54
ZigBee Stack Architecture (1/2) ZigBee Characteristics Application/Profiles Application Framework ZigBee or OEM (User Defined) - Addressing Assign the address to node depend on network configuration - Location Network/Security Layers MAC Layer IEEE ZigBee Alliance Platform Have a location information depend on a network topology in sensor network - Synchronization PHY Layer Common Sync Technology is used (NTP, RBS, TPSN, FTSP) USN 개요 -I 55
ZigBee Stack Architecture (2/2) Application Initiate and join network Manage network Determine device relationships Send and receive messages Application ZDO Security functions Network organization Route discovery Message relaying App Support (APS) SSP NWK Medium Access (MAC) Physical Radio (PHY) Device management Device discovery Service discovery Device binding Messaging USN 개요 -I 56
ZigBee Device Types ZigBee Coordinator (ZC) One required for each ZB network. Initiates network formation. ZigBee Router (ZR) Participates in multihop routing of messages. ZigBee End Device (ZED) Does not allow association or routing. Enables very low cost solutions USN 개요 -I 57
ZigBee Network Topologies <Mesh> ZigBee Coordinator ZigBee Router ZigBee End Device USN 개요 -I 58
결론 USN 개념및소개 RFID 기술및응용 센서네트워크장점및응용 USN 플랫폼구성요소및역할 USN 기술및요구사항 무선센서네트워크표준 USN 개요 -I 59
참고문헌 유승화, RFID/USN 시장및기술동향, 2004. S. Birari and S. Iyer, PULSE : A MAC Protocol for RFID Networks, USN2005, Dec. 2005. J. R. Cha and J. H. Kim, "Performance evaluation of EPCglobal Gen 2 protocol in wireless channel," in Proc. OPNETWORK 2006, Washington D.C, USA, Aug. 28 - Sep. 01, 2006. 차재룡, 김재현, "RFID 시스템에서의태그수를추정하는 ALOHA 방식 Anti- collision 알고리즘," 한국통신학회논문지, 제 30권, 9A, pp.814-821, 2005년 9월. ISO/IEC 18000-6:2003(E), Part 6: Parameters for air interface communications at 860-960 MHz, Nov. 26, 2003. Auto-ID Center, Draft Protocol Specification for a Class 0 Radio Frequency Identification tag., 2003. Jong T. Park, "Management of Ubiquitous Sensor Network," APNOMS Tutorial, Okinawa, Japan, 2005. B. Heile, "Wireless Sensors and ControlNetworks: Enabling NewOpportunities with ZigBee," ZigBee Alliance, 2006. ZigBee Alliance, ZigBee-2007 Specification: ZigBee Document 053474r16, 2007. 오승환, WiMedia UWB환경하에서동기화및 QoS 제공메커니즘연구, 2007. USN 개요 -I 60