Connectivity Weakness Impacts on Coordination in Wireless Sensor and Actor Networks

The combination of sensor and actor nodes in wireless sensor actor networks (WSANs) has created new challenges notably in coordination. In this paper, we survey, categorize, and bring into perspective existing researches on weak connectivity and its impacts on coordination ranging from a node failure to disability of actor nodes to communicate with other actors permanently. We present challenges in each category alongside existing provisions and approaches in the context of the proposed coordination-oriented connectivity categorization. Alongside explanation of general concepts for a communication generalist, we compare the proposed protocols using parameters related to weak connectivity and coordination. Powerful actors can help weaker sensors in many aspects such as routing and data forwarding and many sensors can help few actors in the regions that actors are sparsely deployed. Actors can carry, move and charge sensors while sensors can detect partitions of inter-actor network. Considering lessons learned from surveyed works, we show that actor and sensor nodes in a WSAN must cooperate to provide an integrated network when network connectivity is weak.