Slide 12009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

Energy Efficient Communications Solutions for Nomadic Energy Efficient Communications Solutions for Nomadic NodesNodes

Within a Wireless Sensor NetworksWithin a Wireless Sensor Networks

Luca Bencini, Francesco Chiti, Giovanni Collodi, Davide Di Palma, Romano Fantacci, Antonio Manes, Gianfranco Manes

Department of Electronics and Telecommunications – University of Florence

Slide 22009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

OUTLINEOUTLINE• Introduction• Application area• System Requirement• Mobile Directive Synchronous Transmission Asynchronous Reception Protocol

• Proposed MAC Protocol• State Diagram• Discovery phase• Regime phase

• Performance Analysis• Relative lifetime gain• Collision probability• Latency

• Conclusion and future development

Slide 32009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

APPLICATION AREAAPPLICATION AREA

• habitat monitoring

• healthcare applications

• home automation

• traffic control

• robot applications (DustBot)

nomadic Wireless Sensor Network application areas

Slide 42009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

SYSTEM REQUIREMENTSYSTEM REQUIREMENT

• low power consumption

• low latency

• low collision probability

• good synchronization between nodes and nomadic nodes

cross-layer protocol

MD-STAR

Slide 52009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

Mobile Directive Synchronous Transmission Asynchronous Reception Protocol

MD-STAR protocol:

• is a novel cross-layer protocol

• allows the managements of smart antennas

• takes into the account the antenna capabilities (directivity)

• allows achievement of space-time synchronization for mobile nodes in mesh topology networks

MD-STAR PROTOCOLMD-STAR PROTOCOL

Slide 62009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

STATE DIAGRAMSTATE DIAGRAM

INIT

OFF

DISCOVERY

REGIME

Switch on

fdf Nn <

fdf Nn = sNremptysecto =

lowbatterybattery _<

lowbatterybattery _<

sNremptysecto =≤1

Slide 72009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

DISCOVERY PHASEDISCOVERY PHASE

init

off

discovey

regime

Switch on

fdf Nn <

fdf Nn = sNremptysecto =

lowbatterybattery _<

lowbatterybattery _<

sNremptysecto =≤1

time

fupset TT 2≥−

slf TTT += slf TTT +=

2

4

5

3 2

4 1

ID-node phase sector

2 T-phase 3

ID-node phase sector

2 T-phase 3

3

ID-node phase sector

2 T-phase 4

Slide 82009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

REGIME PHASEREGIME PHASE

init

off

discovey

regime

Switch on

fdf Nn <

fdf Nn = sNremptysecto =

lowbatterybattery _<

lowbatterybattery _<

sNremptysecto =≤1

timefT

lT

fTlTsT sT

4

2

3

5

ID-node phase sector

4 T-phase 3

1

23

42

3 2

4 1

ID-node phase sector

2 T-phase 2

ID-node phase sector

2 T-phase 2

ID-node phase sector

2 T-phase 2

Slide 92009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

Rate 250 Kbps

Number of nodes [10, 15, …., 50]

Number of angular sector

[1, 2, 4, 6, 8]

Monitored area 25 m x 25 m

Velocity of mobile node [4,1 : 5,1] m/s

PERFORMANCE ANALYSISPERFORMANCE ANALYSIS

• mobility model: Random Waypoint Model (RWM)• antenna model: ideal Switched Beam antenna

Parameter considered to evaluate the performance of MD-STAR: • relative lifetime gain

• collision probability

• latency

Slide 102009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

RELATIVE LIFETIME GAINRELATIVE LIFETIME GAIN

Slide 112009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

COLLISION PROBABILITYCOLLISION PROBABILITY

Slide 122009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

LATENCYLATENCY

Slide 132009 Radio & Wireless Symposium, San Diego, CA.2009 Radio & Wireless Symposium, San Diego, CA.

CONCLUSION AND FUTURE CONCLUSION AND FUTURE DEVELOPMENTDEVELOPMENT

CONCLUSION:

• MD-STAR protocol is suitable for the management of mesh topology networks in presence of nomadic nodes.

• MD-STAR protocol satisfies the system requirement of low power consumption, low latency and low collision probability.

FUTURE DEVELOPMENT:

• modify MD-STAR algorithm to manage mobile nodes using a phased array antenna model.