Thursday, July 24, 2014

Improving network reliability of Wireless Sensor Networks

When talking about network reliability, we should consider the different types of networks as well. For example, Wireless Sensor Networks (WSNs) have the potential of revolutionizing the way wireless technology has been used over the decades.Monitoring critical structures such as high speed railway bridges 
requires the monitoring network to be highly reliable. However, there is still a lack of reliability studies of WSNs since,
  • No attempt to define an accurate fault model from experimental evidence.
  • Fault forecasting methodologies have never been applied to WSNs. 
  • The majority of research results are proved by means of simulation. 
  • No attempt to make the sensor nodes intelligent enough to recall the information of interest despite of corrupted signal sensed at the destination and hence to enhance the reliability of communication
Reliability in WSN reflects a functional unit’s ability to meet performance specifications over a specified period of time and this is often expressed as a probability or mean time to failure (MTTF). Factors affectio the reliablity in WSNs are as follows.
  • Hardware failure
  • Inappropriate communication scheme 
  • Constrained resources in sensor nodes 
  • Error prone wireless communication medium
Various models and techniques are used to improve reliability in WSNs.
1) Clustering is a key technique used to extend the lifetime of a sensor network by reducing energy consumption. Sensor nodes are considered to be homogeneous since the researches in the field of WSNs have been evolved, but some nodes may be of different energy to prolong the lifetime of a WSN and its reliability.
2) Also routing algorithms have been proposed for real-time wireless sensor networks using a hybrid algorithm that can increase reliability and network lifetime criterions[1]
3) A Reliability framework also build for data transport based on the different operational phases of the WSN protocols. For this, a fault model was established to capture the possible failures along with generalized data transport and reliability semantics and also developed a reliability block model based approach that exploits the decomposition of the complex data transport problem into operations and simplifies the investigation of the overall reliability of data transport. [2]
[1] Sanaz Naziri, Majid Haghparast and Somayeh Hasanpoor, “Improving Lifetime and Reliability in Routing Real-Time Wireless Sensor Networks based on Hybrid Algorithm” at Australian Journal of Basic and Applied Sciences, 5(9): 1105-1109, 2011
[2] Faisal Karim Shaikh, Abdelmajid Khelil and Neeraj Suri, “On Modeling the Reliability of Data Transport in Wireless Sensor Networks”, in IEEE international conference in parallel, distribute and network based processing, pp. 395-402, 2007

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