Implementing Application Layer Algorithms to Improve Energy Efficiency of a Proprietary Wireless Sensor Network Routing Protocol

Transcription

1 Implementing Application Layer Algorithms to Improve Energy Efficiency of a Proprietary Wireless Sensor Network Routing Protocol Authors: Vlad Adrian Cealicu, Dr. Abhaya Induruwa

2 A sensor network usually includes: an array of distributed or localized sensors, a network that connects the sensors, a central point of information gathering and a set of computing resources to handle data correlation, event trending, status querying and data mining. In this context the sensing and computation nodes are considered part of the sensor network but in fact some of the computing may be done by the network itself. (Sohrabi, Minoli, Znati, 2007) WSN Definition

3 Recent technological advancements in wireless sensor networks can make a big impact in industry. Abundance of proprietary standards Lack of a standardized protocol that fits all applications Different requirements for specific applications Introduction

4 One of the major challenges when designing an application layer algorithm for wireless sensor networks is scalability and the fact that energy efficiency needs to be taken into account at all levels of the protocol stack. Applications level algorithms that include techniques such as maximum, minimum or average values have been developed for reducing the overall data traffic to save energy

5 Yahya and Ben-Othman (2010) list four major areas that need to be taken into consideration in energy efficient wireless sensor networks: Collisions Overhearing Header control Idle listening could amount to % of the power used for receiving actual packets (Ilyas and Mahgoub, 2004).

6 Three types of routing protocols in wireless sensor networks: Data centric routing protocols Hierarchical routing protocols Location based protocols Literature Review

7 Are not scalable Sensor nodes have to be uniquely identified Topology of the network needs to be stored and updated Provide the functionality and the energy efficiency needed for creation applications Examples of data centric protocols: Sensor Protocols for Information via Negotiation (SPIN ), Directed Diffusion (DD), Rumour Routing (RR), Gradient-Based Routing (GBR), Constrained Anisotropic Diffusion Routing (CADR), Cougar, Active Query Forwarding in Sensor Networks (ACQUIRE). Data centric routing protocols

8 Try to solve the issues of a sink becoming overloaded Suggest creation of clusters Main goal is to manage energy consumption efficiently Create latency within the network Examples: Energy-Adaptive Clustering Hierarchy (LEACH), Threshold-Sensitive Energy-Efficient Sensor Network Protocol (TEEN) and Adaptive TEEEN, Power- Efficient Gathering in Sensor Information Systems (PEGASIS). Hierarchical routing protocols

9 Location information can be used to route data in an energy efficient manner. Examples: Minimum Energy Communication Network (MECN) and Small MECN, Geographic Adaptive Fidelity (GAF), Geographic and Energy Aware Routing (GEAR). Location based protocols

10 Detailed software architecture in Jenie Janie/JenNet Protocol Stack and Demo Application Critical Appraisal

11 Star Network Topology Janie/JenNet Protocol Stack and Demo Application Critical Appraisal

12 The original application had a node sleep time of 100ms: Total power per cycle = (time to wake up * power for wake up) + (time to read the sensor * power for reading the sensor) + (time to perform CCA back-off * power for back off period) + (time for CCA * power for CCA) + (time to transmit data * power for data transmission) + (time in sleep * power for sleep period) The average current charge is / ( ) = / ma(miliamp) = mah. The end node equipped with two AAA Alkaline batteries from the original configuration would run for 2400 mah /1.111 mah 2160 hours 90 days. Janie/JenNet Protocol Stack and Demo Application Critical Appraisal

13 Changed the network topology Tree Janie/JenNet Protocol Stack Application Changes for Energy Efficiency and Precision Agriculture Optimization

14 Among the energy efficient changes that can be applied to the demo system available in the Jennic Evaluation Kit and that are also suitable for precision architecture the author has noted: the need to aggregate data at router level the need for a new architecture that relies on clusters the fact that data should not be sent unless it brings additional information or it is used to inform the router/controller that the node is still alive the need to keep the end nodes in sleep mode for as long as possible. Janie/JenNet JenNet Protocol Stack Application Changes for Energy Efficiency and Precision Agriculture Optimization

15 The new application has an end node sleep time of 10 minutes Total power per cycle = (time to wake up * power for wake up) + (time to read the sensor * power for reading the sensor) + (time to perform CCA back-off * power for back off period) + (time for CCA * power for CCA) + (time to transmit data * power for data transmission) + (time in sleep * power for sleep period) The average current charge is 1262 / ( ) = 1262 / ma = mah. The end node equipped with two AAA Alkaline would run for 2400 mah / mah hours days 130 years. If you take into account that on average the data is sent only once each 3 cycles then, on the two Alkaline batteries the node should run for: 2400 mah / mah = hours = days 136 years. Janie/JenNet JenNet Protocol Stack Application Changes for Energy Efficiency and Precision Agriculture Optimization

16 Agile development focuses mainly on adapting to change and delivering high quality products trough simple work processes.(torgeir Dingsoyr, Tore Dybå, Nils Brede Moe 2010) Implementing a new system always causes unforeseen problems and the best way to deal with these creeping requirements is to applying the agile approach. It has also allowed the authors to easily adapt the software based on partial tests.(williams and Cockburn 2003) Testing: design-implement-test-design-... Agile Development

17 Each part of the application was thoroughly tested before its integration into the project. The project was a small scale application and the compilation of the code was easily done after each new feature implemented. This made testing a lot easier. The test data is not available because it was produced and displayed on the LCD display of the controller node. The main focus was on ensuring the topology is correctly implemented and that the connectivity was present. The application was tested under different weather conditions to ensure that the sensors work correctly. The results of the testes were satisfactory and the application is working as intended. Testing

18 An overview of current protocols developed for wireless sensor network was presented The protocols were critically appraised and energy efficient methods have been discovered and noted An application was developed in accord with the best software engineering practices available. The total calculated power efficiency ratio is (days)/ 90(days) 555. The new system has the end nodes 555 times more energy efficient than the previous system.(the calculations do not take into account the "self discharge" rate of the battery and are based on the Jennie/JenNet manual. ) Conclusions

19 Allowing the Controller node to communicate with a computer. The computer has the necessary resources to store and analyze the data. Further investigation into energy efficient design of software for wireless sensor networks Further investigation into the protocols available for wireless sensor networks A closer analysis of energy efficiency in other domains (Eg. Monitoring of patients in a hospital) Further investigation into the use of RFID in wireless sensor networks Further research in the area of actuators in wireless sensor networks Implementation of the actuator system Implementation of the security algorithm Future Plans

20 Any questions?...