Efficient Energy Managem ent Protocol for Target Tracking Sensor Networks X. Du, F. Lin Department of Computer Scien ce North Dakota State Universit y Fargo, ND 58105 USA h IFIP/IEEE International Symposium on Integrated Network Managemen h IFIP/IEEE International Symposium on Integrated Network Management (IM), 2005 (IM), 2005 Chien-Ku Lai
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Efficient Energy Management Protocol for Target Tracking Sensor Networks X. Du, F. Lin Department of Computer Science North Dakota State University Fargo,
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Efficient Energy Management Protocol for Target Tracking Sensor Networks
X. Du, F. LinDepartment of Computer Science
North Dakota State UniversityFargo, ND 58105
USA
9th IFIP/IEEE International Symposium on Integrated Network Management9th IFIP/IEEE International Symposium on Integrated Network Management (IM), 2005(IM), 2005
Chien-Ku Lai
Outline
Introduction Network Model The Sensor Network Energy Management
Protocol The Routing Protocol Performance Evaluation Conclusions
Introduction- Wireless Sensor Networks
Many low-power, low-cost small sensors distributed over a vast field
to obtain fine-grained, high-precision sensing data typically powered by batteries usually scattered densely and statically
Introduction- Wireless Sensor Networks (cont.)
A source A sensor node detecting a target and generating
data to report the conditions of the target
A sink An end user or a base station that collects data fr
om the sources
Introduction (cont.)
Most existing researches focus on issues in Network layer Media access control layer Physical layer
Application layer protocols for sensor networks remain a largely unexplored region
Network Model
Network Model
Cella: side lengtha = rr = sensing range
R: transmission rangeR/r 2≧
Network Model- Assumptions
1. Sensor nodes are static, and each sensor node is aware of its own location
SNEM protocol does not require very accurate node locations
2. For most cells, there is at least one sensor node in each cell
The Sensor Network Energy Management Protoc
ol (SNEM)
1. About target tracking
2. Concepts
3. Details
4. Power balance
The Sensor Network Energy Management Protocol (SNEM)
Where is the energy spent The main task of a sensor node is to
detect events perform quick local data processing transmit the data
Power consumption domains Sensing Communication Data processing
SNEM mainly considers how to save energy in communication domain
The Sensor Network Energy Management Protocol (cont.)
Node idle listening consumes 50–100% of the energy required for receiving Stemm and Katz
idle:receive:send ratios are 1:1.05:1.4 The Digitan 2 Mbps Wireless LAN module
idle:receive:send ratios is 1:2:2.5
The idea of SNEM let nodes that do not perform sensing task go to sl
eep
SNEM- About target tracking
Tracking is an important and widely-used application for wireless sensor networks Military
to detect and track enemy troops and tanks Civilian life
to track the movement of wild animals
SNEM- About target tracking (cont.)
In target tracking applications the interesting events happen infrequently with lo
ng intervals of inactivity
Most sensor nodes can go to sleep during the inactivity period only a small number of nodes stay alert to detect t
he presence of the target
SNEM
SNEM is particularly designed for target tracking sensor networks
The scheme lets most sensors go to sleep while only the sens
ors near the moving target keep active saves energy for sensor nodes
while at the same time keeps tracking the moving target and sends the target information to the sink
SNEM (cont.)
The network operations have two stages The watching stage
no target is present in the field The tracking stage
sensor nodes track the moving target
SNEM- Concepts
Moving target
Relay cellTN: Target Neighbor cell
TN
TN
SNEM- Details
Each sensor node stores two state variables Cell status
indicating the status of the cell Active time
the time to keep the node active
Relay Point (RP) the active node in a relay cell
SNEM- Details (cont.)
Sleeping nodes periodically awake after every ta second depends on
the size of the cell – a the maximum speed of the target - vt
a/vt
SNEM- Details (cont.)
When the status of a cell changes from relay to TN the RP will periodically broadcast a cell status upd
ate message to all nodes in the cell for every tb seconds
When a sleeping node awake it will keep active for tb seconds
The broadcast will repeat for times
SNEM- Details (cont.)
When the cell status becomes to relay nodes will broadcast a Relay Point (RP) message
to other nodes in the same cell with a delay
The remaining energy
Random back off time
SNEM- Details (cont.)
If the target moves very fast the Target Neighbor cells include the cells two ste
p (or even several steps)
Then the sensor sleep time ta can be set as 2a/vt
SNEM- Power balance
When the current RP (say A) uses about 1/3 of its energy A will include its remaining energy and a retiring
indication in a broadcast message when another node B is awake and finds out it
has more remaining energy than A, it will send a take-over message to A
The Routing Protocol
The Routing Protocol
Several routing protocols have been developed for sensor networks Directed Diffusion Leach Mesh
Do not work well with SNEM only one node in each relay cell is active
The Routing Protocol (cont.)
A routing protocol is needed jointly considers the node sleeping scheme in the
application layer and data dissemination in network layer
The Routing Protocol (cont.)
Routing cells cells are in the direction from source to
destination
The Routing Protocol (cont.)
A: source
B: destination
The Routing Protocol (cont.)
Contention-based mechanism with RTS/CTS is used in MAC layer
Nodes in TN send a CTS packet with a delay
Performance Evaluation
1. Performance under Different Node Density2. Different Source-Sink Distances3. The Delay Performance4. Resilience to Sensor Node Failures5. Tracking Performance
Performance Evaluation- Parameters
Simulator : QualNet The underlying MAC : 802.11 DCF Sinks : 4 Sensor Nodes : 900 Deployment : Random Area : 300m x 300m Simulation time : 600s Transmission range : 40m Sensing range : 20m Cells : 15 x 15 = 225 The probability of node failure : 0.1
Performance under Different Node Density- Delivery Ratio
Performance under Different Node Density- Energy Consumption
Different Source-Sink Distances
- Delivery Ratio
Different Source-Sink Distances
- Energy Consumption
The Delay Performance
- Average delay
Resilience to Sensor Node Failures- Delivery ratio
Resilience to Sensor Node Failures - Energy consumption
Tracking Performance- Target tracking quality
Conclusions
Conclusions
Sensor Network Energy Management protocol (SNEM) is a novel energy management protocol for target tracking
sensor networks exploits the features of target tracking applications and
sensor networks allows sensor nodes that are far away from targets go to
sleep save lots of energy while guarantee the accurate tracking
and timely delivery Cell Relay routing protocol
integrates very well with SNEM
Conclusions (cont.)
SNEM scheme performs much better than another energy saving scheme – PEAS a popular routing protocol – Directed Diffusion
SNEM saves significant amount of energy achieves high quality tracking and high delivery ra