A Connectivity Preservation Scheme for Randomly Deployed Wireless Sensor Networks

A wireless sensor network (WSN) consists of spatially distributed low-power sensors for the purpose of monitoring an area of interest such as battle field or environmental conditions such as weather, earthquakes, pressure, etc. These sensor nodes monitor the field, sense and process the monitored data, then deliver the processed data to the sink in a multi-hop fashion. To achieve communication between nodes, network connectivity should be maintained, which is not always the case especially when sensor nodes are randomly deployed. This will result in the appearance of unreachable nodes or isolated nodes. In most of these cases, network will be partitioned and disconnected. Therefore, connectivity is an essential key factor for determining network quality of service (QoS). This thesis focuses on achieving high connectivity for randomly deployed wireless sensors by referring to the concept of building a network virtual backbone approach. Although the concept of connected dominating set (CDS) is used as a method to achieve this purpose; however, this method has limitations in presence of isolated or unreachable nodes. Therefore, this thesis contributes to the CDS approach by adding few anchor nodes at calculated distance to gain high network connectivity. Using MATLAB, extensive simulations have been carried out and the results showed that connectivity has been gained by activating few anchor nodes or spare nodes to random WSNs. Our algorithm had approximately twice the Fiedler value enhancement of Random Addition algorithm. Keywords: Wireless Sensor Networks, Network Connectivity, Anchor Nodes, QoS