The concentration of data traffic towards the sink in a wireless sensor network causes the nearby nodes to deplete their batteries quicker than other nodes, which leaves the sink stranded and disrupts the sensor data reporting. To mitigate this problem the usage of mobile sinks is proposed.
Mobile sinks implicitly provide load-balancing and help achieving uniform energy-consumption across the network. However, the mechanisms to support the sink mobility (e.g., advertising the location of the mobile sink to the network) introduce an overhead in terms of energy consumption and packet delays. With these properties mobile sink routing constitutes an interesting research field with unique requirements.
In this paper, we present a survey of the existing distributed mobile sink routing protocols. In order to provide an insight to the rationale and the concerns of a mobile sink routing protocol, design requirements and challenges associated with the problem of mobile sink routing are determined and explained. A definitive and detailed categorization is made and the protocols’ advantages and drawbacks are determined with respect to their target applications.Distributed Mobile Sink Routing for Wireless Sensor Networks A Survey
In existing distributed mobile sink routing protocols in distributed approaches do not rely on a central entity to manage routes and make decisions; therefore, they are applicable to pure WSN applications where the network consists of mono-type sensor devices. Issues which should be considered for an effective mobile sink routing protocol, and point out the related challenges. We first explain naive, extreme approaches which may serve as rough design.
Then put forward the performance requirements of a protocol in terms of various WSN related performance criteria; give the typical properties and the patterns of the sink mobility, and finally present the sensor capabilities which pose additional challenges or enable various underlying mechanisms aiding or restricting the operation of the mobile sink routing protocols.
To overcome the difficulties in findings routes in case of topology defects, for instance routing around voids, many protocols which extend geographic routing have been proposed. Mobile sink routing protocols that employ geographic routing as the underlying routing solution eliminate the energy and latency cost of route establishment proposed to ensure that these different types of packets intersect at a header (grid point).
Data announcements are propagated horizontally along the grid while data requests are propagated vertically, ensuring that these packets intersect at a crossing point. The position of the sink is then delivered to the source node, and data is delivered directly to the sink. Like TTDD, progressive footprint chaining is used to render the mobility of the sink transparent at the grid.