USN(RFID & WSN) 기술과응용 RFID RFID 핸드북핸드북 Chap Chap 1, 1, Chap Chap 2, 2, Chap13 Chap13 Wireless Wireless Sensor Sensor Networks Networks Chap1, Chap1, Chap2, Chap2, Chap11 Chap11 2004. 8. 11 KAIST EMDEC USN 기초교육 이근호대학연합지능형 UCN 연구센터 & 순천향대학교정보통신융합기술연구센터 ghlee@sch.ac.kr
2. WSN
스마트센서칩기술현황 UC 버클리대학의 스마트더스트 는센서, 통신장치, 컴퓨터능력등을포토리소그래픽기법의 MEMS 나노기술을사용하여 5 5mm 2 로구현. UCLA 에서개발된 MEMS 자계센서는지하 30 미터아래의미세한물체의움직임도감지할수있다.
WSN Projects (1) WINS (Wireless Integrated Network Sensors): UCLA Base on a TDMA structure Separate slots are negotiated between each pair of nodes at network initiation Physical layer employs RF spread spectrum techniques for jamming resistance PicoRadio: UC Berkeley To support the assembly of an ad hoc wireless network of selfcontained low cost, low-energy sensor and monitor nodes
WSN Projects (2) µ AMPS: MIT Emphasizing the need for low power operation Low Energy Adaptive Clustering Hierarchy (LEACH) Node-clustering algorithm Lengthen the lifetime of the network Terminodes, MANET, and other Mobile Ad Hoc Networks: IETF Routing problem created in an ad hoc network when mobility of network nodes is added Underwater Acoustic and Deep Space Networks Employ PSK in the physical layer, a MACA(Multiple Access with Collision Avoidance)-derived protocol for medium access control and multi-hop routing techniques
UC 버클리의 PicoRadio 그림출처 : IEEE MTT-S Workshop 2002
State of the arts WSN: Millennial Net Ultra-low-power: As low as 2 µa at 3 volts Very small: 25 X 15 mm (1.0 x 0.6 inch) Star and star mesh network topologies Up to 250 nodes connection Integrated wireless transceiver and antenna using unlicensed bands Typical 20 meter (60 ft) range Four 8-bit analog input channels Four digital I/O channels or serial I/O port Sample rates up to 10 Hz Data rates to 250 kbps Industrial operating temperature range: -40 to +85 degrees C
WSN Design (1) Successful wireless sensor network design must have several unique features Low Power Consumption : Smart tag, medical sensors Low Cost : Wireless supermarket price tags: ( ad hoc, self-configuration, self-maintenance system) Worldwide Availability : Wireless luggage tags, shipping container location systems Network Type : multi-hop routing through dense networks (mesh) Security Data Throughput : limited (up to 512 bps) Message Latency : QoS Mobility
참고 : 저전력소비 / 로버스트네트워킹기술 다중도약 (Multihop) 네트웍킹기술은전파전송도중의에너지감쇄가거리의지수승 ( 거리 n, n=2~5) 에비래한다는원리를이용, 하나의긴거리전송경로를이용하기보다는여러짧은경로를이용하여전송한다는개념 MESH 네트워크는로버스트한통신네트워크구성
참고 : 보안성 보안은단지메시지암호화 (encryption) 를의미하는것이아니다. 가장중요한보안목표는메시지가보낸이로부터수신자에게도달될때까지어떤식으로든일체수정되지않고도달하는것이다. 예를들면, 무선전등스위치를가지고있는어떤이가전등을켜고끄는것을다른이가알수없어야한다는것이다. 네트워크장비의가격을최소화하기위하여, 보안성은저가의하드웨어로구현해야만하며부가의논리게이트와 RAM과 ROM은최소화해야만한다. 또한, 대부분의네트워크장비에서데이터처리전력은매우제한적이어야한다.
WSN Design (2) Physical layer design Efficient modulation method : good sensitivity and high overthe-air data rate (long battery life) Data link layer design Novel method : low cost, low duty cycle (power efficient operation) Network layer design Message throughput, message delay, effective node duty cycle, channel collision
무선센서관련표준화 IEEE 1451.5 Wireless Sensor Working Group communications interface, manufacturers, implementers, users IEEE 1451.5 Wireless Sensor Working Group Sponsors Technical Committee on Sensor Technology of the IEEE Instrumentation Measurement Society Smart transducer interface Transducers compliant with any other networks Effects of transducer interface standardization Network need only have a single design Network can be duplicated for each sensor A mixed-mode approach is now proposed Wireless Sensor Standard 1451.5 Balloting for this standard is expected in 2004
UWB 관련표준화
새로운 UWB 표준화 IEEE 802.15 SG4a : 고밀도기기환경 ( 단위면적당수백개 ), 고정밀위치추적 (1m 이내의정밀도 ) 을목표 -UWB 응용능동형 ID 태그, 센서네트워크용 FCC 에서최초로승인된 UWB-RFID
UWB 응용네트워크 그림출처 : IEEE Com mag.
IEEE 802.15.4 Low Rate WPAN Standard (1) Scope of IEEE 802.15.4 task group Define the PHY and MAC specifications for low data rate wireless connectivity with fixed, portable and moving devices with no battery or very limited battery consumption requirements typically operating in the Personal Operating Space of 10 meters. Purpose of IEEE 802.15.4 task group To provide a standard for ultra low complexity, ultra low cost, ultra low power consumption and low data rate wireless connectivity among inexpensive devices.
IEEE 802.15.4 Low Rate WPAN Standard (2) IEEE 802.15.4 standard supports. both star and peer-to-peer connections wide variety of network topologies and routing algorithms are possible Address field 16-bit address field, extended to 64-bit addresses Message transmission each frame receive an explicit acknowledgement produces a reliable protocol
IEEE 802.15.4 Low Rate WPAN Standard (3) Other characteristic of the standard designed to minimize power consumption of the network nodes co-existence with other services dynamic channel selection is required scanning other available channel Link Quality Indication (LQI) indication of channel impairment, dynamic channel selection process power control part of relative location determination algorithm, and network routing algorithm
IEEE 802.15.4 Low Rate WPAN Standard (4) Network node Functionality PAN coordinator Initiates the network and is the primary controller of the network Coordinator Transmits beacons and communicates directly with any device in range It may become a PAN coordinator Device Communicates directly only with a coordinator or PAN coordinator Full function device (FFD) Reduced function device (RFD)
IEEE 802.15.4 Low Rate WPAN Standard (5) Two physical layers of the IEEE 802.15.4 standard The lower band, 868.0-868.6 [MHz] BPSK with raised-cosine pulse shaping The upper band, 2.400-2.485 [GHz] O-QPSK with half-sine pulse shaping
Tiny OS Operating system through a set of modular software building blocks Software footprint: 3.4 Kbytes Power consumption on 1st generation (Rene) Platform - transmission Cost: 1 µj/bit (software processing cost) - mote s inactive state: 5 µa - mote s peak load: 20 ma Efficient concurrency support Efficient modularity Events propagate through stack <40 µs 1 Motes organize themselves according to local rules within a hierarchically arranged network.
Zigbee 기술의포트폴리오 1. 근거리 (10 cm - 10 m) 에서낮은데이터전송률 (20-250 kbps) 을갖는저가격, 저전력소비의무선네트워크 ( 네트워크당 255 개의노드연결 ) 기술 2. PHY 로 2.4 GHz 대역 (QPSK 변조방식 ) 의 16 채널, 915 MHz 대역 (BPSK 변조방식 ) 의 10 채널, 868 MHz 대역의한개채널을이용하며매우낮은 duty-cycle(< 0.1 %) 을유지 대역지역전송률채널수 2.4 GHz ISM Worldwide 250 kbps 16 868 MHz Europe 20 kbps 1 915 MHz ISM Americas 40 kbps 10
3. MAC/LLC 로는 WLAN 과같은 CSMA-CA 방식을사용하며 dynamic device addressing 을이용하여네트워크를형성 Application Application Interface Network Layer Data Link Layer MAC Layer MAC Layer PHY Layer Silicon ZigBee Stack Application
Zigbee 표준화 필립스, 모토롤라등이주축이된 Zigbee Alliance 와 IEEE802.15.4 APPLICATIONS APPLICATION INTERFACE SECURITY NETWORK LAYER Star/Cluster/Mesh DATA LINK LAYER MAC LAYER MAC LAYER PHY LAYER 2.4 GHz 915MHz 868 MHz Customer IEEE 802.15.4 ZigBee Alliance Application ZigBee Stack Silicon
Zigbee vs UWB(WiMedia)
Zigbee 응용네트워크 그림출처 : Korwin