Mitsuru Kaji

A Flooding Control Method with Ack-carry for Location-Based Information Dissemination in Mobile Ad Hoc Networks

Flooding is one of the most fundamental approaches to deliver information that is likely to be of interest to surrounding mobile nodes in mobile ad hoc networks. A number of research groups have proposed flooding protocols on purpose to reduce the redundant retransmissions from neighboring nodes. In those approaches, unnecessary transmissions are not minimized in an area where no nodes are interested in the information. In this paper, we propose a flooding method that suppresses transmissions of information to unnecessary nodes in mobile ad hoc networks with some fixed nodes. In the proposed method, when a mobile node passes near the source node of the received information, it sends an acknowledgement (ACK) including the addresses of fixed nodes that relayed the information. Then, the source node attaches those addresses to the information in later transmissions, and the fixed nodes whose addresses are specified in the information expand the flooding area. By doing so, the source node can effectively deliver the information to mobile nodes which are likely to pass near the source node. We confirmed the effectiveness of our proposed method through some simulations.

A Negative Location-Based Information Dissemination Method in Mobile Ad Hoc Networks

Location-based services (LBSs) are important applications for mobile users. We consider an application in which the source node periodically disseminates location-based information in mobile ad hoc networks (MANETs). We define beneficial information as that which may be of benefit to mobile users planning to pass near the location related to the information. However, typically, mobile users change their route or travel direction when the mobile node receives beneficial information such as traffic jam and accident information (we call these information the negative location-based information). Thus, a significant problem lies in determining the proper target area for the dissemination of such information in dynamic networks because the source node is difficult to effectively know where to disseminate it. In this paper, we propose a novel location-based information dissemination method in MANETs by use of some fixed nodes. Our proposed method requires neither a positioning system, nor previous knowledge, to efficiently disseminate the information. However, the fixed nodes autonomously expand the relevant dissemination area. Through simulation experiments, we confirm that the proposed method suppresses ineffectual overhead, and that mobile users can efficiently and early receive the beneficial information.