7. USN-I Sensor Network & ZigBee 2011. 5. 11 안병익 (biahn99@gmail.com) Mcomputing.tistory.com @LBSAHN
모바일 Ad-hoc 네트워크 Review Ad-hoc 은 temporary( 임시의, 임시적인 ) 이란뜻 기존유선네트워크의하부구조또는중앙관리시스템과같은고정된기반망의도움없이이동단말만으로구성된자율적이고독립적이며일시적인네트워크 유선기반네트워크가구축되지않은곳에서손쉽게네트워크구성가능 모바일 Ad-hoc 네트워크기술은지난 20 여년간산발적으로개발 1970 년대초 Mobile Packet Radio 라는무선기반의망기술을개발 모바일노드안으로라우팅기능을추가 Mobile Ad-hoc Network Infrastructure Network
센서네트워크 Review 특정영역내에배치된다수의센서노드들로이루어진유무선네트워크 서비스영역에센서노드들이배치되고네트워크를형성한후필요한실세계 (Physical World) 의정보를수집및처리 센서네트워크의구조 센서노드 (1) Computation: Data processing (2) Sensing: 자연의음성, 빛, 온도, 바람, 습도등을감지 (3) Communication: RF transceiver, Laser module 등 싱크 (Sink) 노드 : 인터넷이나인공위성을통하여사용자와통신 Internet and Satellitee Sink Sensor field active sensor node
센서네트워크 (Routing Protocol) Review Routing Protocol Flooding Directed Diffusion SPIN(Sensor Protocols for Information via Negotiation) LEACH(Low-Energy Adaptive Clustering Hierarchy) 2 3 2 3 6 6 1 1 4 5 4 5 2 3 6 1 4 5
센서네트워크표준 Review 블루투스, ZigBee 등은저속정보전송기술로기기제어등에적합하고, UWB(Ultra- WideBand) 는영상전달등에필수 Bluetooth - 대표적인 WPAN(Wireless Personal Area Network) 무선네트워크기술 IEEE 802.15.4 Sensor Network Standard, 블루투스보다낮은전송속도와저가격, 매우긴배터리수명, 간단한구조및연결성을제공하여 10m 이내의작은범위내에서의무선연결을요구하는분야에적합한표준 Zigbee ( 관련기업연합체 ) 저전력, 저비용이특징인 2.4 GHz 기반의가정용무선네트워크규격 반경 30m 내에서 250 Kbps 의속도로 255 대의기기들연결가능
USN 무선기술정리 Review IEEE 802.15.1 Bluetooth IEEE 802.15.3(High-rate WPAN) IEEE 802.15.3a ( 더높은전송속도, 저전력, 저가격 ) UWB IEEE 802.15.4 (Low-rate WPAN) Zigbee IEEE 802.11a/b/g/n WLAN 6
USN 발전전망개요 Review USN 은우선인식정보를제공하는전자태그를중심으로발전하고, 이에 Sensing 기능이추가되면서이들간의네트워크 (Network) 가구축되는형태로발전할것으로전망
- What is AD HOC Network? Why Ad Hoc? 흔히무선 ad hoc 네트워크라하면무선인터페이스를사용해패킷데이터를전송하는무선노드로구성된, 중앙관리 (central administration) 없이형성된네트워크를뜻한다. 이같은유형의네트워크에있는노드는라우터나호스트로이용될수있기때문에다른노드대신패킷을전송할수도있고, 사용자애플리케이션들을실행할수도있다. Ad hoc 네트워킹의가장매력적인점은, 중앙통제로부터완전히독립해사용자가네트워크사용에더많은자유와유연성을얻게된다는것이다. - AD HOC Network 의특징및요구사항 - 기존유무선네트워크와는달리, ad hoc 네트워크는노드일부나전체가무선인네트워크환경속에서작동할수있다. 이같은다이나믹한환경에서는노드가갑자기사라지거나나타날수있기때문에네트워크기능이분산방식으로작동돼야한다. -Ad hoc 네트워크상의노드는보안및라우팅기능지원을백그라운드네트워크에의존할수없다. 그대신, 이들기능이설계되어분산된조건하에서도효율적으로운영될수있어야한다. - 노드가무선이기때문에네트워크형태가다양해지지만, 그럼에도불구하고네트워크연결이유지돼애플리케이션과서비스를차질없이제공해야한다. 특히이점이라우팅프로토콜설계에영향을미친다. 또한 ad hoc 네트워크사용자는노드가이리저리움직이는상황에서도인터넷과같은유선네트워크에의접속을요구한다. 8
Infra-structured N/W vs. Infra-structureless N/W Internet WLAN Cellular Mobile Ad-hoc Networks 9
Wireless Multihop Networks MANET Mobile Ad Hoc Networks (MANET) Mesh Network Mesh routes (multiple routes) exist between each source-destination pairs Infrastructure-less/Peer-to-Peer Base station is not necessary Lossy, unstable and asymmetric wireless links Bandwidth-constrained, variable capacity links Multi-hop nodes need to relay packets for others The nodes don t need to be of the same type (phone, PDA, laptop, sensor, etc.) 10
What is Ad Hoc Network? In Latin, ad hoc means "for this," further meaning "for this purpose only. All nodes are mobile and can be connected dynamically in an arbitrary manner. No default router available. Potentially every node becomes a router: must be able to forward traffic on behalf of others.
Two types of Wireless Networks Infrastructured network: A network with fixed and wired gateways. When a mobile unit goes out of range of one base station, it connects with new base station. Infrastructureless (ad hoc) networks: All nodes of these networks behave as routers and take part in discovery and maintenance of routes to other nodes.
Why is Ad Hoc hard? Because of a constantly changing set of nodes Routing is a major issue! Security new vulnerabilities, nasty neighbors. Power running with batteries, little computing power.
ZigBee
IEEE 802.15 워킹그룹 목적무선개인영역네트워크 (Wireless Personal Area Networks, WPAN) 또는단거리무선네트워크를위한표준을제정하는것 WPAN은 PC, PDA, 셀룰러폰등의무선이동기기간의통신을가능하게하며, 다른무선통신기술에비해에너지소비가낮고저가이기때문에센서네트워크에도입되기에적합한통신기술로부각되고있음. 특히, IEEE 802.15.4 표준은센서네트워크에서가장적합한통신기술로인정받고있으며, 현재 ZigBee와 6LoWPAN의 MAC(Medium Access Control)/PHY(Physical layer) 표준으로사용되고있음. 802.11b WLAN 802.15.1 블루투스 802.15.4 LR-WPAN 통신거리 100m 이내 10~100m 10m 데이터전송률 2~11Mbps 1Mbps 250kbps 에너지소비 보통 낮음 아주낮음 크기 큼 작음 가장작음 비용및복잡성 높음 보통 낮음
통신기술에따른데이터전송률, 연결성, 에너지소비비교 WLAN IEEE 802.11b IEEE 802.11g IEEE 802.11a 연결성, 에너지소비 IEEE 802.15.4 IEEE 802.15.1 Bluetooth IEEE 802.11 WPAN IEEE 802.15.3 데이터전송률
IEEE 802.15 워킹그룹구성 WPAN IEEE 802.15 TG 15.1 Bluetooth TG 15.2 Coexistence TG 15.3 HR-WPAN (2.5GHz) TG 15.4 LR-WPAN (ZigBee) TG 15.5 Mesh Networking SG 3c mmwave TG 15.3a Alt. PHY(UWB) TG 15.4a Alt. PHY(UWB) TG 15.4b Rev. & Enhance
IEEE 802.15 워킹그룹산하의 Task Group 구분 Task Group 업무 IEEE 802.15 WPAN(TG1) Coexistence(TG2) High Rate(TG3) High Rate(TG3A) Alt.PHY UWB mmwave(sg3c) 10 미터정도근거리에서의무선통신기술의대한표준제정 MAC & PHY 블루투스규격채용 WPAN WLAN 와의전파간섭축소방법연구 20Mbps MAC 및 PHY 연구 2.4GHz ISM(11.22.33.44.55Mbps 메시지전송 ) TG3 PHY 100Mbps 이상고속화하기위한 alternative PHY (UWB) 연구 TG3a(60GHz) 활용한초고속 alternative PHY 연구 Low Rate(TG4) ZigBee Low Rate(TG4a) Alt. PHY UWB Mesh Networking (TG5) 최대전송속도 20~250Kbps MAC 및 PHY 연구 2.4GHz ISM, 868/915MHz Dual PHY UWB PHY 이용한저속위치인식네트워킹연구 WPAN MAC 및 PHY 연구
What is ZigBee? What is ZigBee? Specification of protocols for small, low-power radios Technological Standard Created for Control and Sensor Networks Based on the IEEE 802.15.4 Standard Created by the ZigBee Alliance History May 2003: IEEE 802.15.4 completed December 2004: ZigBee specification ratified June 2005: public availability ZigBee-Alliance Companies developing and promoting the standard 150+ members
Difference between ZigBee & WiFi ( 규격 ) ZigBee (IEEE 802.15.4) Bluetooth (IEEE 802.15.1) Wi-Fi (802.11 IEEE) 속도 250Kbps 64k~1Mbps Up to 54Mbps 송신전류 25~35mA 40mA 400mA 이상 전송거리 100m이내 10m이내 100m이내 ( 실내 ) 1~2Km( 실외 ) Standby전류 3mA 200uA 20mA 주파수 868MHz( 유럽 ) 2.4GHz 2.4GHz 915MHz( 북미 ) 2450MHz(( 전세계 ) 응용 lilighting, Interoperalbility, Enterprise, Sensors, Cable replacement Home Access Points PC Peripherals 메모리 4, 16, 60Kbyte 100Kbyte 이상 100Kbyte 이상
ZigBee Alliance ZigBee Alliance 프로모터 Chipcon, 필립스 (Philips), 미쓰비시 (Mitsubishi), 모토로라 (Motorola), Honeywell, Freescale, Ember, 삼성 + 100 개이상참여기업 * 국내에서도 LG, TTA, 한국무선네트워크 (korwin), 한국전자통신연구원 (ETRI) 등다수의기업및연구단체가참여기업으로활동하고있음. 목표 : 2003 년완성된 IEEE 802.15.4 표준을기반으로저전력무선네트워킹이가능한모니터링및제어 (control) 제품을위해상위프로토콜표준을정의하는것 Application Layer ZigBee Alliance 표준화작업범위 Application Framework Network/Security Layer ZigBee Alliance IEEE 802.15.4 MAC/PHY IEEE
ZigBee Alliance - Members and many more...
IEEE 802.15.4 & ZigBee In Context Application API Security 32- / 64- / 128-bit encryption Network Star / Mesh / Cluster-Tree MAC PHY 868MHz / 915MHz / 2.4GHz Silicon Stack App Customer ZigBee Alliance IEEE 802.15.4 the software Network, Security & Application layers Brand management IEEE 802.15.4 the hardware Physical & Media Access Control layers Source: http://www.zigbee.org/resources/documents/iwas_presentation_mar04_designing_with_802154_and_zigbee.ppt
ZigBee Alliance 주요기업들이개발한제품 ZigBee Alliance 는기업들이주축이된만큼표준제정과동시에참여기업들에의한제품생산이이루어지고있음 기업 제품명 기능 Chipcon CC2420 2.4GHz 802.15.4 시스템 CompXs CS1540 단일칩으로구성된 802.15.4 Freescale Semiconductor MC13193 802.15.4 2.4GHz 저전력송수신기 Ember copporation EmverZNet ZigBee 프로토콜스펙 wireless Z-stack ZigBee 프로토콜스펙
Why do we need another WPAN standard? Decreasing Power consumption ZigBee: 10mA <==> BT: 100mA Production costs In the beginning of 2005 ZigBee: 1.1 $ <==> BT: 3 $ Development costs Codesize ZB/codesize BT = ½ Bit-error-rate (BER)
Why do we need another WPAN standard?
Why do we need another WPAN standard? Increasing Sensitivity ZigBee: -92dbm(0,63pW) <==> BT: -82dbm(6,2pW) flexibility No. of supported nodes ZigBee: 65536 (in a mesh) <==> BT: 7 (in a star) Security ZigBee: AES (128bit) <==> BT: SAFER (64/128bit) Latency requirements ZigBee: optional guaranteed time slot Range ZigBee: up to 75 m in LOS condition <==> BT: 10 m
Usage Scenarios Industrial & commercial Consumer electronics Toys & games PC & periphals Personal health care home/building automation Just everything you can imagine for wireless sensor nodes or in general short range communications
ZigBee Frequency Bands
ZigBee Protocol Stack 7Layer ISO-OSI-Model Simplified 5Layer ISO-OSI-Model IEEE 802 Model 7 Application User Application <<ZigBee 6 Presentation 5 Session Application Profile Upper Layers 4 Transport 3 Network Network 2 Data Link Data Link Logic Link Control (LLC) <<802.14.5 Media Access Control (MAC) 1 Physical Physical Physical
ZigBee Protocol Stack ZigBee Stack 은 OSI(Open Systems Interconnection) 7 계층모델을기반으로한계층적구조
ZigBee 의계층구성 ZigBee 는계층구조로구성된다. 하위계층은 IEEE 802.15.4 중간은 ZigBee 그리고상위계층은 OEM회사들에서 정의한다.
ZigBee Profiles Profiles: Definition of ZigBee-Profiles describes a common language for exchanging data defines the offered services device interoperatbility across different manufacturers Standard profiles available from the ZigBee Alliance profiles contain device descriptions unique identifier (licensed by the ZigBee Alliance)
IETF 6 LoWPAN 워킹그룹 목적 IEEE 802.15.4 MAC/PHY 상위계층으로 IP 및 TCP/UDP 등의기존인터넷에서사용하는통신프로토콜을이용하는환경에서의 IPv6 패킷전송방안을결정하는것 IPv6 를사용 - 기존에구축된인프라를그대로이용가능 추가비용절감, 잘알려지고검증된 IP 기술들을많은수정없이사용가능, IPv6 의큰주소공간과자동주소설정과같은기능을 LoWPAN 에적용하는데유리
6LoWPAN 워킹그룹작업범위 Application Layer Transport Layer (TCP/UDP) Network Layer (IPv6) IETF Application Layer 6LoWPAN WG IEEE 802.15.4 MAC/PHY IEEE
IPv6 Convergence 워킹그룹 IPv6 Convergence IPv6 포럼코리아에서 IPv6를이용한 convergence 에관련된활동을추진하는국내워킹그룹 2005sus IPv6 포럼코리아의워킹그룹을개편하며, IPv6 Convergence 를 IPv6 의주요이슈로생각하여 IPv6 Convergence 워킹그룹을신설. 목적 1. 분야에대한구분없이 IPv6를적용할수있는영역을찾아이에필요한협력을이끌어내는것. 2. 국내에 IPv6 기술을조기에도입하고 IPv6와관련된시장을활성화시키는것 관련기관들의협력및기술적내용이슈등의공유를통해워킹그룹차원의가이드라인또는국내표준문서등을작성하는것 2005 년부터활동을시작하였으며, 산업체, 연구소, 학계로구성된정규멤버들이격월로워킹그룹정기회의를갖고있음
The 802 Wireless Space Source: http://www.zigbee.org/en/resources/
ZigBee and Other Wireless Technologies Source: http://www.zigbee.org/en/about/faq.asp
ZigBee Aims Low Low data rate Low power consumption Small packet devices
ZigBee Frequencies Operates in Unlicensed Bands ISM 2.4 GHz Global Band at 250kbps 868 MHz European Band at 20kbps 915 MHz North American Band at 40kbps
What Does ZigBee Do? Designed for wireless controls and sensors Operates in Personal Area Networks (PAN s) and deviceto-device networks Connectivity between small packet devices Control of lights, switches, thermostats, appliances, etc.
Lights and Switches Source: ZigBee Specification Document
How ZigBee Works Topology Star Cluster Tree Mesh Network coordinator, routers, end devices
How ZigBee Works States of operation Active Sleep Devices Full Function Devices (FFD s) Reduced Function Devices (RFD s) Modes of operation Beacon Non-beacon
ZigBee Mesh Networking Slide Courtesy of Source: http://www.zigbee.org/en/resources/#slidepresentations
ZigBee Mesh Networking Slide Courtesy of Source: http://www.zigbee.org/en/resources/#slidepresentations
ZigBee Mesh Networking Slide Courtesy of Source: http://www.zigbee.org/en/resources/#slidepresentations
ZigBee Mesh Networking Slide Courtesy of Source: http://www.zigbee.org/en/resources/#slidepresentations
ZigBee Mesh Networking Slide Courtesy of Source: http://www.zigbee.org/en/resources/#slidepresentations
ZigBee and the Hype Cycle Source: http://danielneamu.rdscv.ro/cutenews/images/gartner_hype_cycle_4.jpg
Architecture
ZigBee Node-Types ZigBee Coordinator (ZBC) (IEEE 802.15.4 FFD) only one in a network initiates network stores information about the network all devices communicate with the ZBC routing functionality bridge to other networks
ZigBee Node-Types ZigBee Router (ZBR) (IEEE 802.15.4 FFD) optional component routes between nodes extends network coverage manages local address allocation/de-allocation
ZigBee Node-Types ZigBee End Device (ZBE) (IEEE 802.15.4 RFD) optimized for low power consumption cheapest device type communicates only with the coordinator sensor would be deployed here
Addressing/Discovering ZigBee Nodes Addressing ZigBee Nodes: optimized unique 64 bit address (IEEE 802.15.4) 16 bit network address (65536 devices) 256 sub addresses for subunits Device Discovery unicast (NWK id known), broadcast (NWK id unknown) ZBC-/ZBR-Response: IEEE address + NWK address + all known network addresses Binding creating logical links between 2 or more end devices
Addressing/Binding ZigBee Endpoints picture taken from [11]
Traffic-Types 1. Data is periodic application dictates rate 2. Data is intermittent application or stimulus dictates rate (optimun power savings) 3. Data is repetitive (fixed rate a priori) device gets guaranteed time slot
Traffic-Modes 1. Beacon mode: beacon send periodically Coordinator and end device can go to sleep Lowest energy consumption Pricise timing needed Beacon period (ms-m) picture taken from [1]
Beacon-Mode picture taken from [8]
Traffic-Modes 1. Non-Beacon mode: coordinator/routers have to stay awake (robust power supply needed) heterogeneous network asymmetric power picture taken from [1]
Topologies Mesh-Topology picture taken from [7]
Topologies Tree-Topology picture taken from [7]
Implementation
Application Level
Application Level
Application Layer Application Support Sub-layer (APS): interface to NWK-layer (offers general set of functions) Data transmission, binding and security management
Application Level
Application Layer Application Framework: Specifies Datatypes Devices describe themselves by ZigBee descriptor: frequency band power description application flags application version serial number manufacturer...
Application Level
Application Layer ZigBee defined Objects (ZDO): provides common function for applications Initializes APS, NWK-Layer and Security Service Specification offers services like device-/service-descovery, binding and security management assembles information about the network for ZBC/ZBR -> e.g. binding table
Zigbee 기술 (1) CSMA(Carrier Sense Multiple Access) 충돌방지알고리즘 CA : Collision Avoidance CD : Collision Detection
Zigbee 기술 (2) DSSS (Direct sequence spread spectrum ) 스펙트럼확산방식의하나로, 디지털신호를매우작은전력으로넓은대역으로분산하여동시에송신하는것 특징 이방식은우수한잡음방지성능을가지고있으며, 데이터를중간에서가로채기가어려워보안성이우수하다는등의장점이있으나, 수신기의구조가복잡해지는등의단점이있다 직접시퀀스 (DS) 확산스펙트럼신호의스펙트럼분석기사진. 원래신호 ( 비확산 ) 가중앙로브의절반만을차지하고있다.
Zigbee 기술 (3) 저가격 (SSSP 스펙트럼확산기술 ) 저전력 ( 슈퍼프레임구조 ) 보안성 (List Table, Integrity Code)