Project Introduction

이 상 신이 상 신

Korea Electronics Technology InstituteKorea Electronics Technology Institute

2

Contents

• Wireless Surveillance System based on WSN

• Forest Fire Monitoring System

• The Unmanned Tracking System based on WSN

Wireless Surveillance System based on WSN

4

Overview of Wireless Sensor Network

• What is wireless sensor network?– A large group of many networked sensors to monitor conditions

• temperature, sound, vibration, pressure, and motion

– Sensor network nodes have• Sensing, computation, and networking abilities

– Sensor network features• Low cost, small size, low power consumption

• Application areas of WSN– Environmental monitoring, fire detection, seismic detection, military

surveillance, and so on

• What is the best protocol in a specific application?• AODV@SMAC? ZigBee?

– There are so many different requirements as each application area

• We designed an optimized protocol in specific application area• R-WSLP (Real-time Wireless Sensor Line Protocol)

5

Wireless surveillance system

• Wireless surveillance system based on wireless sensor networks

– For detecting the incursion of unauthorized objects or intruders

– To assist guard soldiers in the military demarcation line

– Burglar alarm, protecting critical infrastructures, and homeland

defense

6

Requirements of wireless surveillance system

• Requirements of wireless surveillance system

– Low latency in multi-hop communication

• Primary Requirement & our major goal

– Low power consumption

– High reliability

• Features of wireless surveillance system

– Linear sensing field

– Low traffic environment

– No mobility

– Directed data path (end sink)

7

The Basic Idea of R-WSLP

• Latency in multi-hop communication

– Mainly caused by sleep delay originating from periodic sleep for reducing energy consumptio

n

• Real-time Wireless Sensor Line Protocol (R-WSLP)

– Proposed for minimizing the network latency

– Solve the sleep delay problem in the multi-hop network

– Utilize periodic listen and sleep mechanism

• to minimize power consumption

Superframe(SuperframeDuration)

Active Period Inactive Period

ActiveDuration InactiveDuration

SuperframeDuration = ActiveDuration * (2^SuperframeOrder), where 2 <= SuperframeOrder <= 15

8

The Basic Idea of R-WSLP

• Immediate forwarding– if a node receives a message from its child node – immediately forwards the message to the parent node

• Time synchronization according to the data path– Time synchronizes with the parent node

• Nodes achieve local time synchronization using the information of neighbor node– peer-to-peer time synchronization

9

Network Topology of R-WSLP

• In peer-to-peer time synchronization, the nodes requires pre-determined dat

a path

• Using ad hoc linear network

– Linear topology

– Easy to use peer-to-peer time synchronization

• Because topology itself means data path

– Suitable for wireless surveillance system

• Linear sensing field

• Low traffic environment

• No mobility

• Directed data path (end sink)

10

Network Topology of R-WSLP

• Select data path by routing

algorithm

• If the data path is corrupted

– nodes select a new data

path using update routing

information

• Select data path when they are

joining to the network

• If the data path is corrupted

– try to recovery

• Ad hoc mesh network

• Ad hoc linear network

11

Time Synchronization

Node 1

Node 2

RX

Data

TX

Data

RX A

ck

RX

Data

TX

Data

RX A

ck

RX

Data

TX

Data

RX A

ck

Superframe

RX

Data

TX

Data

RX A

ck

RX

Data

TX

Data

RX A

ck

RX

Data

TX

Data

RX A

ck

Node 3

• Forwarded messages without sleep latency

• Synchronize TX Data Slot to Parent’s RX Data Slot

• Using SFD (Start Frame Delimiter ) of Sync Frame

• Nodes select their time slots according to the time schedule of the parent node

– It is not conflicted with time schedule of neighbors

Data Frame ACK and Sync Frame

12

R-WSLP Overview

1 2 3 4 5 6

Mnc = Max Node Count / MAX RF Range

CRI : Collision Resolution Interval

1

5

6

7

8

9

10

11

12

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX

RX

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

RX TX ACK

TX ACK

ACK

2

3

4

CR

I

13

Latency

• Latency of R-WSLP

Processing time

Processing time

1 Hop Latency

n-1

n

n+1

RxAck

Sleep

Guard

tproctfd

Frame duration

tfd

tfd tfd

tfdtfd

tguard

Guard time

tproc

tproc

14

Low power consumption

• For low power consumption

– Every node repeats periodic sleep and wakeup

– Divide superframe into active period and inactive period.

– Each node communicates during active period and goes to sleep during

inactive period.

• To minimize network delay

– Use piggyback acknowledgement mechanism

– To save the time required for acknowledgement, nodes send the data packet in th

e TX period with acknowledgement packet

15

Low power consumption

Sleep RxAckRxData TxDataO

SC

on

Bio

s on P

LL

Loc

k&R

X o

n

t osc

t bios

t rx

/tx_o

n

Sle

ep

t rx_a

ck

Processing

Sle

ep

OS

C o

n

Bio

s on

RX

PL

L L

ock&

TX

on

tsleep ttx_data

Sle

ep

OS

C o

n

Bio

s on P

LL

Loc

k/R

X o

n

trx_data

TX

RX

Guard Sleep Sleep WaitAck

tguard

tproc twait_ack

• Energy Consumption

16

The Process for Joining a Network

• Composed of several procedures as followsA. Neighbor scan

To search the neighbor nodes which could be parent node

B. Select the parent

Is there a terminal node? • Yes -> Select the terminal node

• No -> select the neighbor node which has the greatest RSSI value

C. Synchronization

Synchronize the time with the parent node

D. Contention for joining

In case of two or more nodes try to join the same node

E. Sending a join request message

Sends a join request message to a parent node for joining a network

17

Select the parent

• In the result of scan, a terminal node exists

– Select the terminal node as the parent

• Terminal node does not exist

– Select the parent node of a link which has the most RSSI value

• Just one neighbor node

90

M

SMMMT

New

SMMMT

New

SMT

New

609085

SMM

65

M

Selected

90 60 30

T M M

Selected

Cannot be selected

Sync Frame

The result of scan

time

18

Contention for joining

• Used the RSSI value for resolving contention problem

zone1

zone2

zone3

zone4

zone5

19

Reliability Support

• R-WSLP should guarantee the reliability– One of the most important issues to alarm emergency situation

• To support this requirement we offer the recovery mechanism – for the node failure and the link failure

Recovery for the node failure and the link failure

Extend their time slot for their new child node or new parent node

20

Hardware Platform for Wireless Surveillance System

• The hardware platform of sensor node for wireless sur

veillance system

– network module

• used the Chipcon’s CC2420(2.4GHz) for wireless communi

cation and msp430 and as micro controller

• Also, used Chipcon’s CC1000 for 900MHz band

– sensing module

• used Honeywell’s HMC 1002 as magnetic sensor

• SensorTec STMA-506 as ultrasound sensor

21

Conclusion

• Low delay & Low energy consumption

– R-WSLP achieves low network latency by eliminating sleep delay

– R-WSLP guarantees fast delivery in low duty cycle network

– The network latency in R-WSLP is not affected by duty cycle.

• Implementation of the wireless surveillance system

• Future Works

– Required low power sensors for wireless surveillance system

– Try to apply various real time applications

• Tree topology & ring topology

• Real time backbone network

Forest Fire Monitoring System

23

Forest Fire Monitoring System

• Real time Forest Fire Monitoring System

Experiment

(at KETI’s Security Fence)

The Unmanned Tracking System based on WSN

25

Introduction

26

System Structure

Tracker Remote Controller

Control System Application

· Command· Control· Communication· Computing· Intelligence· Surveillance· Reconnaissance

Control System

Control System /

u-Sensor Node Interface

Tracker System Application

· Control· Communication· Computing· Calibration

Tracker System /

Tracker Remote controller

Interface

u-Sensor Network Radio

Tracker Control

SensingSensing

Control System/

Tracker ControllerInterface

u-Sensor Node Application Layer

· Sensing· Communication

u-Sensor Node

u-Sensor Node Sensing Block

u-Sensor Node Communication

Block

u-Sensor Network / Tracker System

Interface

u-Sensor Node Application Layer

· Sensing· Communication

u-Sensor Node

u-Sensor Node Sensing Block

u-Sensor Node Communication

Block

u-Sensor Network

u-Sensor Node Application Layer

· Sensing· Communication

u-Sensor Node

u-Sensor Node Sensing Block

u-Sensor Node Communication

Block

u-Sensor Network

27

Sensor Network Module

Sensor Network NodeSensor Network Node Network ModuleNetwork Module

Sensor ModuleSensor Module

powerpower • 1.2V, 2500mA hr, AA (3)•

• 2-axis magnetic sensor : Honeywell HMC1002 (±2G)

•Ultra sound sensor : SensorTec STMA-506 (5m)

28

Sensor Arrangement

Magnetic Sensor

Range : 4m

Sonar sensor

Range : 0.3m~5m

29

Location Awareness

30

Demo Scenario

31

Demo

Field Test

Server침입자 /추적자

Magnetic Sensor

Range : 4m

Sonar sensor

Range : 0.3m~5m

Directivity : 10°

32

Control & Monitoring S/W