Information Share and Propagation Issues in Ad Hoc Network along with Its Simulation Evaluations

Abstract

Information share and propagation is one of primary aims in constructing ad hoc network. In this paper, Issues on information share and propagation in ad hoc network are expounded and analyzed. Available schemes and existent problems are outlined. Then, information share and propagation in ad hoc network are evaluated via simulation in various experiment scenarios in detail, including infection model, information chain-reacting system and multi-hop information propagation system. In the end, conclusions are drawn.The main objective of computer network is to share and interchange information. As one special kind of mobile computer network, ad hoc network also has the same objective [1]. Since only sharing and intercommunicating information effectively, network effectiveness can be exerted fully. Without losing generality, ad hoc network can be seen as one kind of data store-and-forward system independent of underlying routing algorithms. For example, ad hoc network can forward data by using pull and push based data transmission mode [2] and mobile uses can obtain data form servers or access points (APs) connecting with Internet and exchange information with other interested users. Such information share assumes such one fact that is information share in certain geographical range possesses high localization trait and the objective is to improve the availability of data [3]. The focus of this article is how nodes in ad hoc network cooperate to implement information share and transmission. Traditional ad hoc networks assume nodes are cooperative, but this assumption is not suitable for commercial environment in which users are selfish in nature, that is one user will not forward or share data coming from other users unless he can obtain benefits. In this paper, assuming mobile users query interested data periodically and popularity of information can be reflected by query frequency on information in unit time. I. Information Share and Propagation SchemesIn general, mobile hosts in ad hoc network can exchange information in certain manner and can obtain related information from local servers. In addition, in some cases, mobile hosts can access Internet via temporary or fixed gateways. Mobile hosts and servers can send request and response by broadcasting messages. For example, some hosts can inquire information by broadcasting request messages and some hosts can broadcast announce messages containing its information indices (such as information titles and formats) in memory periodically or on demand. In ad hoc network, each host integrates functions of client and server and includes a memory manager and a message response and issue mechanism. Memory manager is responsible for storing and searching information in memory according to certain rules and information is marked by its attributes including media formats (such as RM or MP3), information contents and access rights, etc. Information in memory is associated with a index file and index file facilitates searching related information [4]. Query messages contain att...