Papers by Keyword: DTN

Abstract: In the research of Delay Tolerant Network (DTN), DTN routing algorithm is a key research issue. The performance of a non-flooding routing algorithm is verified in our paper. The verified algorithm is an Adaptive Priority Routing Algorithm (APRA) which is based on fuzzy strategies. Firstly, we introduce the principle of APRA, then using Opportunistic Network Environment (ONE) -simulation software to compare the performance of Epidemic algorithm, Spray and Wait algorithm, PRoPHET algorithm and APRA. By comparing overhead of netword, rate of messages delivered and average dealy, it finds that the APRA performs better. At last, the weaknesses of this paper and further improvement are also discussed.

Abstract: . In allusion to the high delay, restricted nodes resources and lack of persistent end to end connections in Delay /Disruption Tolerant Networks ( DTN) ,this paper proposes a novel directed flooding routing algorithm based on location information. The algorithm combines DTN with the known nodes locations in communication channel to improve the DTN networks topology knowledge to reduce the noneffective duplicate,then conducts single duplicate routing depending on location. The algorithm can increase the directivity and purposiveness of message transmission, decrease the consumption of networks resources, and thereby reduce propagation delay and improve the delivery ratio. The simulation shows that the proposed algorithm is feasible and effective, and it is superior to the typical DTN routing algorithms such as Epidemic Routing.

Abstract: Mobility models are drawing increasing attention since it plays an indispensable role in delay tolerant networks performance evaluation (e.g., routing performance evaluation). Random Waypoint with Base Point (RWPBP) mobility model aims to model the movement characteristics in catastrophe rescue scenario. RWPBP mobility model can represent different movement styles according to different parameters. In this paper, we consider the traffic scenario that all the data generated by the nodes need to be sent to the base point, and evaluate the performance of the five DTN routing protocols (i.e., DirectDelivery, Epidemic, PROPHET, SpayAndWait and FirstContact) under the RWPBP mobility model with different parameters. Epidemic performs best in our experiment, since the traffic is not heavy in catastrophe rescue scenario.

Abstract: This Delay/Disruption Tolerant Network(DTN) is a New Network Architecture for Communication in Restricted Condition with High Latency and Intermittent Connectivity.In Order to Solve the Problem that Messages can Not be Delivered Reliably because of Mobility and Limited Buffer Size of Nodes in DTN,a Probabilistic Routing Algorithm Based on Node Free Buffer-Utilization (NFBU)is Proposed.The Algorithm Sets Node Free Buffer Warning/excitation Threshold,through Warning/incentive Factor to Increase/decrease the Node Forwarding Probability,and Set up the Buffer Management Strategy,message Time to Live(TTL)value is Smaller,the Higher its Priority,at the same Time Remove the Oldest Message to get more Buffer Space.Simulations Indicate that the Algorithm Improves Delivery Ratio and Reduces Network Latencies in Different Node Free Buffer-Utilization State Compared with some other Routing Algorithms,and it is Highly Adaptable to Network.

Abstract: Congestion control is a very important problem which can affect network performance directly. However, owing to the lack of steady end-to-end connection and high latency, the traditional congestion control mechanism based on end-to-end feedback is not feasible in DTN. Because obtaining the global information of network is difficult, the congestion control decisions should be made autonomously with local information only. We propose a novel distributed congestion control algorithm based on epidemic routing protocols----MACRE (Message Admission Control based on Rate Estimation). Preliminary experimental results show that this congestion control mechanism can improve the network performance efficiently.