Sogang University ICC Lab Sensor Networks - Introduction.

106
Sogang University ICC Lab Sensor Networks - Introduction

Transcript of Sogang University ICC Lab Sensor Networks - Introduction.

Page 1: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab

Sensor Networks

- Introduction

Page 2: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.2

목차

센서 네트워크 개요

센서 네트워크 플랫폼

센서 네트워크 MAC

센서 네트워크 라우팅

센서 네트워크 응용

센서 네트워크 표준화

Page 3: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.3

센서 네트워크 개요 Definition

Network of sensor nodes with computation, sensing, wireless

communication capabilities

What we can do with Sensor Netowkrs?

Sensing (Actuation) : Motion -> Image -> Classification

Collaboration:

Mobile sensors: tracking

Page 4: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.4

센서 네트워크 개요 Features

Embedded computer with sensors and radios

Sensing target in proximity

Large number of densely distributed nodes

Multi-hop, wireless, ad hoc network

Sensing, processing, communication, actuation

Page 5: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.5

센서 네트워크 응용 서비스

Page 6: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.6

Hardware Platforms Crossbow (Mica Series)

Intel Mote (iMote)

Moteiv (Telos, Tmote SKY)

Maxfor (TIP 시리즈 )

옥타컴 (Nano-24)

Page 7: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.7

Crossbow (Mica Series) 미국 버클리대학에서 미국 국방성의 DARPA 프로젝트 스폰서를 받아 개발

현재 가장 범용적으로 사용되는 하드웨어 플랫폼

Rene, dot, Mica, Mica2, MicaZ

TinyOS, 각종 시뮬레이터 및 다양한 공개 응용이 제공됨

메인보드에 온도 , 조도 , 지자기 센서 등의 센서를 스택 형식으로 장착 가능

Page 8: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.8

Intel Mote (iMote) UC Berkeley 와 Intel Research Berkeley Lab 에서 공동 연구로 개발

ARM 기반의 마이크로 프로세서 사용

32bit ARM7TDMI CPU 사용

센싱 정보의 복잡한 계산이나 상위 레벨의 복잡한 정보 처리 가능

Zeevo 社의 2.4GHz 대역의 Bluetooth 사용

최대 720kbps 전송률 지원

cf) ZigBee 의 경우 250kbps

TinyOS 를 ARM instruction set 에

맞게 포팅하여 사용

http://www.intel.com/research/

exploratory/motes.htm

Page 9: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.9

Moteiv (Telos, Tmote SKY) MCU 로는 Texas Instruments 社의 MSP 430 사용

짧은 wake-up time (6μs), 낮은 소모 전력 (Active: 15mW,

Sleep: 15μW), 낮은 동작전원 ( 최소 1.8V)

cf) ATmega128 의 경우 180μs, 33mW, 75 μW, 2.7V

RF 모듈로 Chipcon 사의 CC2420 칩 사용

센서 노드용 OS 로 TinyOS 사용

http://www.moteiv.com/

Page 10: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.10

Maxfor (TIP 시리즈 ) 한국전자부품연구원 (KETI) 에서 개발

TIP 3X 시리즈

MCU: ATMega 128L

900MHz 대의 RF 칩 사용 (Chipcon 社의 CC1000)

TIP 5X, 7XX 시리즈

MCU: MSP430

2.4GHz 대역의 RF 사용 (Chipcon 社의 CC2420)

센서 운영체제로 TinyOS 사용

http://www.maxfor.co.kr/

Page 11: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.11

옥타컴 (Nano-24) ETRI 에서 개발한 센서 노드 운영체제인 Nano-Qplus 사용

Crossbow 社의 MicaZ 와 유사한 보드 구성

Atmega 128L CPU 사용

Chipcon 社의 CC2420 RF 칩 사용

조도 , 온도 , 습도 , 적외선 , 가스 , 초음파 , 가속도 센서등 다양한

종류의 센서를 스택형식으로 장착 가능

Page 12: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.12

옥타컴 (Nano-24)

Nano-24 메인 모듈

Page 13: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.13

옥타컴 (Nano-24)

Page 14: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.14

센서 네트워크 운영체제 TinyOS

SOS

MANTIS

나노 Qplus

Page 15: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.15

센서 운영체제 요구 사항 제한된 자원의 효율적 사용을 위해 저전력 통신을 지원해야 하고 ,

프로세서의 메모리 영역의 효율적인 관리를 수행해야 함

센서노드는 설치된 후 유지보수가 어려우므로 동적으로 환경에 적응 할

수 있는 능력 필요

센서 노드의 통신 거리 제약을 극복하기 위해 멀티 홉 라우팅 지원

응용 프로그래머들의 손쉬운 프로그래밍을 위한 API 제공

Page 16: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.16

TinyOS UC 버클리의 Smart dust 프로젝트에서 개발

이벤트 발생 중심의 상태 변화 방식

효율적인 CPU 사용

슬립모드 지원

nesC

센서 네트워크용 프로그래밍 언어

동적 메모리 할당 사용 안함

안정성을 위해 전체 프로그램에 대한 분석을 통해 최적화 수행

컴포넌트 기반의 언어

멀티 홉 라우팅 제공

추가 모듈 지원 : TinyDB, TinySec

Page 17: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.17

TinyOS

컴포넌터 기반의 TinyOS 예제

Page 18: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.18

SOS Mote 계열 기반의 센서 네트워크 지원을 목적으로 UCLA 에서 개발

메시지 패싱 , 동적 메모리 할당

Common Kernel 지원

커널의 동적 재구성 지원

무선 네트워크를 통해 센서 노드의 소프트웨어 업데이트 수행

응용 애플리케이션은 하나 이상의 모듈로 구성

비동기 메시지 및 함수 호출을 통해 서로 동작함

Page 19: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.19

MANTIS 콜로라도 대학에서 개발된 센서 네트워크용 임베디드 운영체제

초소형 스레드에 기반한 멀티 스레드 구조

일반 프로그래머들이 익숙한 구조

특징

레이어 기반 운영체제

멀티 스레딩 지원

Preemptive 스케줄링

Mutual exclusion 을

통한 I/O 동기화

하드웨어를 추상화

시키는 디바이스 드라이버

Page 20: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.20

나노 -Qplus 한국전자통신연구원 (ETRI) 에서 개발된 센서 네트워크 운영체제

특징

에너지 소모를 최소화하기 위해 노드들간의 시간 동기화 기법을

제공

멀티 스레드간의 스택을 공유하여 메모리 사용을 줄일 수 있음

멀티 스레드 스케줄러 방식

실시간 운영체제 (RTOS) 지원

C 기반의 응용프로그램 개발환경 지원

Page 21: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.21

나노 -Qplus 구조

Nano-HAL (Nano Hardware Abstract Layer)

• 하드웨어를 추상화하기 위해 개발된 디바이스 드라이버 영역

• LED, Clock. Power, RF 모듈 , UART, ADC

태스크 스케줄러 (Task scheduler)

• Linux 스타일의 스케줄러와 유사

• 저전력 및 효율적인 리소스 관리 제공

• POSIX 스레드 기반의 API 를 통해 멀티 스레드간 메시지 전달

Page 22: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.22

나노 -Qplus 동적 전원관리

• 처리할 태스크가 없을 경우 전원 소비가 늦은 실행모드로 전환

RF 메시지 핸들링

• IEEE 802.15.4 기반의 멀티홉 라우팅 형성을 돕는다 .

시간 동기화

• 노드들 사이의 듀티 사이클을 조정하기 위한 모듈이다 .

• 트리기반의 시간 동기화 기법 제공

Page 23: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.23

나노 -Qplus

Nano-Qplus 구조

Page 24: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.24

센서 네트워크 MAC IEEE 802.15.4 MAC

S-MAC

B-MAC

Page 25: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.25

센서 MAC 개요 Low-power capacities lead to limited coverage and

communication range for sensor nodes

The primary objective in wireless sensor networks design is

maximizing node/network lifetime.

The communication of sensor nodes will be more energy

consuming than computation

The medium-access decision within a dense network

composed of nodes with low duty-cycles is a challenging

problem that must be solved in an energy-efficient manner

Page 26: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.26

MAC-Layer-Related Sensor Network Properties Reasons of Energy Waste

Collision

Overhearing

Control-packet overhead

Idle listening

Overemitting

Communication Patterns

Broadcast

Convergecast (opposite to broadcast or multicast)

Local gossip

multicast

Page 27: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.27

Important Consideration in Wireless Sensor Network MAC Power Consumption

Channel Occupancy

Throughput, Latency & Fairness

Self-Organization and Self-Maintenance

Scalability

Quasi-Stationary Assumption

Unlicensed Frequency Bands

Page 28: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.28

IEEE 802.15.4 MAC

Upper Layers

IEEE 802.2 LLC Other LLC

IEEE 802.15.4

2400 MHz

PHY

IEEE 802.15.4

868/915 MHz

PHY

IEEE 802.15.4 Architecture

Page 29: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.29

IEEE 802.15.4 MAC Overview Star and peer-to-peer topologies

Employs 64-bit IEEE & 16-bit short address

Two devices specified

Full Function Device (FFD)

Reduced Function Device (RFD)

Page 30: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.30

IEEE 802.15.4 MAC Overview Simple frame structure

Reliable delivery of data

Association/disassociation

AES-128 security

CSMA-CA channel access

Optional superframe structure with beacons

GTS (Guaranteed Time Slot) mechanism

Page 31: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.31

IEEE 802.15.4 Devices Full function device (FFD)

Any topology

PAN coordinator capable

Talk to any other devices

Implements complete protocol set

Page 32: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.32

IEEE 802.15.4 Devices Reduced function devices (RFD)

Limited to star topology or end-device in a peer-to-peer

network

Cannot become a PAN coordinator

Talks only to a network coordinator

Very simple implementation

Reduced protocol set

Page 33: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.33

IEEE 802.15.4 Definitions Network devices: An RFD or FFD implementation containing an

IEEE 802.15.4 medium access control and physical interface to

the wireless medium.

Coordinator: An FFD with network device functionality that

provides coordination and other services to the network.

PAN Coordinator: A coordinator that is the principal controller

of the PAN. A network has exactly one PAN coordinator

Page 34: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.34

Full function device

Reduced function device

Communications flow

Master/slave

PANCoordinator

IEEE 802.15.4 MAC- Star Topology -

Page 35: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.35

Full function device Communications flow

Point to point Cluster tree

IEEE 802.15.4 MAC- Peer-to-Peer Topology -

Page 36: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.36

Full function device

Reduced function device

Communications flow

Clustered stars - for example,cluster nodes exist between roomsof a hotel and each room has a star network for control.

IEEE 802.15.4 MAC- Combined Topology -

Page 37: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.37

IEEE 802.15.4 MAC Addressing All devices have IEEE addresses (64 bits)

Short address (16 bits) can be allocated

Addressing modes

PAN identifier (16bits) + device identifier (16/64 bits)

• 0x0000 – 0xfffd

• 0xfffe, 0xffff

• Beacon frame: no destination address

Page 38: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.38

Data Service Data transfer to neighboring devices

Acknowledged or unacknowledged

Direct or indirect

Using GTS service

Maximum data length (MSDU)

aMaxMACFrameSize (102 bytes)

Page 39: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.39

S-MAC (Sensor-MAC)The main features of S-MAC are: Periodic listen and sleep

Each node goes into periodic sleep mode during which it switches the radio off and sets a timer to awake later

Collision and Overhearing avoidance Message passing

Page 40: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.40

S-MAC

Choosing and Maintaining Schedules

Schedule table

• The schedules of all its known neighbors

Maintaining Synchronization

SYNC packet

• The address of the sender and the time of its next sleep

Adaptive Listening

To switch the nodes from the low-duty-cycle mode to a

more active mode

Page 41: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.41

S-MAC

Page 42: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.42

B-MAC (Berkeley MAC)

B-MAC’s Goals:

Low power operation

Effective collision avoidance

Simple implementation (small code)

Efficient at both low and high data rates

Reconfigurable by upper layers

Tolerant to changes on the network

Scalable to large number of nodes

Page 43: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.43

B-MAC Features

Clear Channel Assessment (CCA)

Low Power Listening (LPL) using preamble sampling

Hidden terminal and multi-packet mechanisms not provided,

should be implemented, if needed, by higher layers

Sleept

ReceiveReceiver

Sleept

PreambleSender Message

Sleep

Page 44: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.44

B-MAC Interface

CCA on/off

Acknowledgements on/off

Initial and congestion backoff in a per packet basis

Configurable check interval and preamble length

Page 45: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.45

Constraints No centralized coordinator

Dynamic network topology

Bandwidth constrained wireless links

Careful resource management

Transmission power

On-board energy

Processing capacity

Storage

Channel access availability

Hidden/Exposed terminal problem

Lack of symmetrical links

Page 46: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.46

Sensor Network Architecture

Sensor Nodes

Sink

Internet 및 기존 유무선 망

Task Manager User

Page 47: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.47

System Architecture & Designing

Network Dynamics

Mobile or Stationary nodes

Static Events (Temperature)

Dynamic Events ( Target Detection)

Node Deployment

Deterministic – Placed manually

Self-organizing – Scattered randomly

Page 48: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.48

System Architecture & Designing

Energy Considerations

Direct vs. Multi-hop communication

• Direct Preferred – Sensors close to sink

• Multi-hop – unavoidable in randomly scattered

networks

Data Delivery Models

Continuous

Event-driven

Query-driven

Hybrid

Page 49: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.49

System Architecture & Designing Node Capabilities

Homogenous

Heterogeneous

Nodes dedicated to a particular task (relaying, sensing,

aggregation)

Data Aggregation/Fusion

Aggregation – Combination of data by eliminating redundancy

Data Fusion is Aggregation through signal

processing techniques

Aggregation achieves energy savings

Page 50: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.50

센서 라우팅 분류

Routi ng Protocol s

Network Structure Protocol Operati on

Fl atNetworksRouti ng

Hi erarchi calNetworksRouti ng

Lacati onBased

Routi ng

Negoti at i onbased

Routi ng

Mul t i -pathbased

routi ng

Querybased

routi ng

QoSBased

Routi ng

Coherentbased

Routi ng

Page 51: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.51

센서 라우팅 예시

Data Centric Protocols

SPIN , Directed Diffusion

Hierarchical Protocols

LEACH

Location Based Protocols

GAF , GEAR

Page 52: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.52

Sink sends queries to certain regions and waits data from sensors

located in that region

Attribute-based naming is necessary to specify properties of data

Data Centric Routing

Page 53: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.53

Data Centric Routing Flooding

Gossiping

Sensor Protocols for Information via Negotiation (SPIN)

Directed Diffusion

Energy-aware Routing

Rumor Routing

Gradient-Based Routing (GBR)

Constrained Anisotropic Diffusion Routing (CADR)

COUGAR

ACtive QUery forwarding In sensoR nEtworks (ACQUIRE)

Page 54: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.54

Data Centric Routing Flooding

Sensor broadcasts every packet it receives

Relay of packet till the destination or maximum number of

hops

Causes Implosion, Overlap & Resource Blindness

Gossiping

Enhanced version of flooding

Sends received packet to a randomly selected neighbor

Problems of Implosion, Overlap, Resource Blindness

Page 55: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.55

SPIN

Network-wide Broadcast Limited by Negotiation and using

Local Communication

Flooding problems:

Implosion – same data from many neighbors

Detection of overlapping regions

Excessive resources consumption (Blindness)

Needs only Localized Information

Data Fusion

Two main protocols SPIN-PP & SPIN-BC

Page 56: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.56

Data Aggregation

Methods of Aggregation

Duplicate suppression

Aggregate functions like Avg,Min,Max etc

Data Aggregation Trees

Center At Nearest Source

Shortest Path Tree

Greedy Incremental Tree

Page 57: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.57

Data is described by meta-data ADV msg. Node has data sends ADV to neighbors If neighbor do not have data sends REQ Node responds by sending the DATA This process continues around the network Nodes may aggregate their data to ADV In a Lossy Network ADV may be repeated periodically and REQ if not

answered

SPIN-PP (Point-to-Point Communication)

Page 58: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.58

ADV and DATA sending like PP (but in B.C.)

Since only one REQ answer is needed, any node waits a random

interval and B.C. REQ only if none was received yet.

The rest – like SPIN-PP

SPIN-BC (Local Broadcast Communication)

Page 59: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.59

ADVNode with data

Node with data advertises to all its neighbors

Example of SPIN-PP

Page 60: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.60

REQNode with data

Neighbor requests for data and it is sent

Example of SPIN-PP

Page 61: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.61

DATA Node with data

Node with data advertises to all its neighbors

Example of SPIN-PP

Page 62: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.62

Node with dataADV

Receiving node sends ADV to neighbors

Example of SPIN-PP

Page 63: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.63

Node with data

Receiving neighbors requests for data.

REQ

Already has data(or dead)

Example of SPIN-PP

Page 64: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.64

Node with data

DATA

Receiving node sends ADV to neighbors

Example of SPIN-PP

Page 65: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.65

Directed Diffusion

Sensor node names data with one or more attributes that it

generates

Other nodes express interests based on these attributes

Sink nodes query sensor network for information from a

particular section of the terrain

Page 66: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.66

Directed Diffusion

Network nodes propagate interests

Interests establish gradients that direct diffusion of data

Path of interest propagation sets up a reverse data path for

data that matches the interest

As it propagates, data may be locally transformed (e.g.

aggregated) at each node, or be cached

Rest is similar to conventional routing

Page 67: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.67

Directed Diffusion - Rules for Interests and Gradients -

What are the local rules for propagating interests? E.g., just flood interest More sophisticated techniques possible: directional interest

propagation, based on cached aggregate information What are the local rules for establishing gradients?

In example, highest gradient towards neighbor who first sends interest

Others possible e.g., towards neighbor with highest remaining energy

Page 68: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.68

Directed Diffusion - Data Transmission Choices -

Different local data forwarding rules can result in different

kinds of transmission

single path delivery

multi-path delivery, with traffic on each link proportional to

its gradient

• data probabilistically striped along different paths

• redundant delivery across different paths

• layered transmission along different paths

delivery from single source to multiple sinks

delivery from multiple sources to multiple sinks

Page 69: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.69

Directed Diffusion - Reinforcement Variants -

Can define several criteria for selecting which path is reinforced

amount of data received from neighbor

loss rates

observed delay variance

Can define local message processing or state aging rules that

allow variants of reinforcement behavior

reinforce a small number of source-sink paths (instead of

one)

negatively reinforce a path, because, for example, some

node in the path is running low on resources

Page 70: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.70

Example of Directed Diffusion - Interests and Gradients -

Sink

Source

Thickness of line proportional to gradient

Interest

Gradient

Page 71: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.71

Example of Directed Diffusion - Data Transmission -

Sink

Source

Page 72: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.72

Example of Directed Diffusion - Data Transmission -

Sink

Source

Page 73: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.73

Example of Directed Diffusion - Data Transmission -

Sink

Source

Page 74: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.74

Example of Directed Diffusion - Reinforcing Gradients -

Sink

Source

Page 75: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.75

Example of Directed Diffusion - Reinforcing Gradients -

Sink

Source

Page 76: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.76

Example of Directed Diffusion - Reinforcing Gradients -

Sink

Source

Page 77: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.77

Example of Directed Diffusion - Reinforcing Gradients -

Sink

Source

Page 78: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.78

Hierarchical Protocols

When sensor density increases single tier networks cause

Gateway overloading

Increased latency

Large energy consumption

Clustered Network allow coverage of large area of interest and

additional load without degrading the performance

Page 79: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.79

Hierarchical Protocols

Hierarchical routing Uses Multi - hop communication within a cluster Performs data aggregation and fusion on data to reduce number of

transmitted messages to the sink Maintain the energy reserves of nodes efficiently

Example - LEACH, PEGASIS

Page 80: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.80

LEACH

Self-Organizing – Adaptive Clustering

Cluster-Heads elect themselves

“Random Round-Robin”

Stationary Sink

Localized Coordination

Data Fusion

Basic Algorithm assumes any node can communicate with sink

– limited scale

Page 81: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.81

LEACH Operation

Page 82: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.82

LEACH Operation

Page 83: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.83

Location Based Protocols

Location information can be used to Find shortest path to the sink Form a virtual grid and keep only few nodes active at a time

Example GAF GEAR

Page 84: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.84

Determining Location

Location of a node can be determined using

Global Positioning System

Ultrasonic Systems using trilateration

Beacons

Location based protocols assume that each node knows its

location in the network

Page 85: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.85

TinyOS Routing Protocol

Tree-based Routing protocol

Constructed and maintained by periodic hello (called

‘RoutePacket’) message exchange

Network Topology is changed through link quality estimation

Support of Broadcast and Multi-hop Routing

Broadcast: sink node to all sensor nodes

• Ex. a command message from sink node to sensor nodes

Multi-hop: each sensor to sink

• All unicast messages of sensor node are sent to its parent

node (ex. sensing message forwarding)

Page 86: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.86

TinyOS Routing Protocol

InternetInternet

sink

Tree topology construction

Page 87: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.87

TinyOS Routing Protocol

(n+1, 20)

(Hop Count, link quality)

(n, 32)

(n, 17)

(n+1, 40)

(n+2, 23)

(n+1, 22)

(n, 21)

(n,27)

(n+1, 24)

(n+2, 26)

Before RoutePacket exchange, node states

After RoutePacket exchange, link quality estimation update

(n+1, 22)

(n+1, 17)

Forwarding path

Periodic RoutePacket Exchange

Page 88: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.88

센서 네트워크 응용 구조도

Page 89: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.89

센서 네트워크 응용 예제

Page 90: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.90

센서 네트워크 서비스 모델

Page 91: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.91

국내 센서 네트워크 구축 예

한국전산원

농산물 재배환경 모니터링 시스템

제주 해양환경 정보수집 시스템

한국전자통신연구원 (ETRI)

스마트 오피스

지하 시설물 관리

한국전자부품연구원 (KETI)

산불 모니터링 시스템

Page 92: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.92

농산물 재배환경 모니터링 시스템

Page 93: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.93

제주 해양환경 정보수집 시스템

Page 94: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.94

스마트 오피스 (ETRI)

Page 95: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.95

지하 시설물 관리 (ETRI)

Page 96: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.96

산불 모니터링 시스템 (KETI)

Page 97: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.97

산불 모니터링 시스템 (KETI)

Page 98: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.98

센서 네트워크 표준 기술

IEEE 802.15.4

IEEE 802.15.4b

ZigBee

IEEE 1451.5

IPv6 over LoWPAN (6LoWPAN) of IETF

Page 99: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.99

IEEE 802.15.4a Scope and Description:

Develop an alternate physical layer for data

communication with high precision ranging/location

capability/ (1m accuracy and better) , high aggregate

throughput, and ultra low power; as well as adding

scalability to data rates, longer range, and lower power

consumption and cost

The alternate PHY is an (optional) amendment to the

current IEEE 802.15.4-2003 LR-WPAN standard.

802.15.4a became an official Task Group in March 2004;

with its committee work tracing back to November 2002

Page 100: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.100

IEEE 802.15.4a Current Status

The baseline is two optional PHYs consisting of UWB

impulse Radio (operating in unlicensed UWB spectrum) and

a Chirp Spread Spectrum (operating in unlicensed 2.4 GHz

spectrum)

The UWB Impulse Radio will be able to deliver

communications and high precision ranging

Page 101: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.101

Overall Enhancements in IEEE 802.15.4b

Added support for distributing a shared time-base

Support for group addressing

Added extensions of the 2.4GHz derivative modulation

Yields higher data rates at the lower frequency bands

Added support of Beacon-Enabled Cluster Tree network

IEEE 802.15.4 does not support while 15.4b does

Protection of broadcast and multicast frame possible

Easier setup of protection parameters possible

Possibility to vary protection per frame, using a single key

Optimization of storage for keying material

Page 102: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.102

ZigBee Alliance

Page 103: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.103

ZigBee vs. WLAN vs Bluetooth

Page 104: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.104

IEEE 1451

The IEEE 1451, a family of Smart Transducer Interface

Standards, describes a set of open, common, network-

independent communication interfaces for connecting

transducers (sensors or actuators) to microprocessors,

instrumentation systems, and control/field networks.

Page 105: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.105

6LowPAN

IPv6 over Low power WPAN

Why IPv6

More suitable for higher density

Statelessness mandated

No NAT necessary

Possibility of adding innovative techniques as location

aware addressing

IEEE 64 bit address subsumed into IPv6 address

Page 106: Sogang University ICC Lab Sensor Networks - Introduction.

Sogang University ICC Lab.106

Challenges of 6LoWPAN