Browse Theses

In this thesis, we investigate how to design efficient publish/subscribe (pub/sub) protocols for wireless ad hoc networks. We review the existing pub/sub protocols designed for wireless ad hoc networks. Based on the review of previous studies, we proposed a 3-D framework for protocol design in wireless ad hoc networks. We describe three novel pub/sub protocols designed, respectively, for wireless sensor networks (WSNs), wireless mesh networks (WMNs), delay-tolerant networks (DTNs). The proposed protocols take the advantage of the geographical information of the network nodes to achieve high performance in event subscription and delivery.

First, we describe HESPER , a Highly Efficient and Scalable Publish/subscribe protocol designed for wireless sEnsoR networks. HESPER uses the geographical information of the interesting events to efficiently disseminate subscriptions without flooding and establish the event delivery paths shared by subscribers without the coordination among the subscribers. Thus, HESPER can reduce the amount of traffic for event delivery and, thus significantly save energy of WSNs.

Then, we propose a novel PUb/sub protocol for wireless Mesh networks based on locAtion prediction, namely PUMA, which can reliably and efficiently deliver events to mobile clients in a continuous manner. Using the location prediction for a mobile client, PUMA can deliver the interesting events to the location where a mobile client may stay. To further reduce the message cost, PUMA first disseminate the events to the locations, namely hot locations, where a mobile client has a higher probability to stay. Thus, PUMA can guarantee the reliability of event delivery with low cost.

Next, we propose a publish/subscribe (pub/sub) protocol, called GIANTs, that uses geographical information to improve the reliability and efficiency of event service for DTNs. To guarantee the specified event delivery ratio and reduce the redundant every delivery, GIANT first constructs an event delivery tree with optimal number of hops on the paths from the publishers to the subscribers, and then, uses the location information of forwarding nodes to minimize the number of ferries to be recruited on each hop. Thus, in addition to flexibility and reliability, GIANT also achieves high efficiency.