• International Journal of Computer Science & Network Security
• /
• v.22 no.2
• /
• pp.167-174
• /
• 2022

Vehicular Ad hoc Networks are considered as special kind of Mobile Ad Hoc Networks. VANETs are a new emerging recently developed, advanced technology that allows a wide set of applications related to providing more safety on roads, more convenience for passengers, self-driven vehicles, and intelligent transportation systems (ITS). Delay Tolerant Networks (DTN) are networks that allow communication in the event of connection problems, such as delays, intermittent connections, high error rates, and so on. Moreover, these are used in areas that may not have end-to-end connectivity. The expansion from DTN to VANET resulted in Vehicle Delay Tolerant Networks (VDTN). In this approach, a vehicle stores and carries a message in its buffer, and when the opportunity arises, it forwards the message to another node. Carry-store-forward mechanisms, packets in VDTNs can be delivered to the destination without clear connection between the transmitter and the receiver. The primary goals of routing protocols in VDTNs is to maximize the probability of delivery ratio to the destination node, while minimizing the total end-to-end delay. DTNs are used in a variety of operating environments, including those that are subject to failures and interruptions, and those with high delay, such as vehicle ad hoc networks (VANETs). This paper discusses DTN routing protocols belonging to unicast delay tolerant position based. The comparison was implemented using the NS2 simulator. Simulation of the three DTN routing protocols GeOpps, GeoSpray, and MaxProp is recorded, and the results are presented.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.806-809
• /
• 2012

DTN (Delay Tolerant Network)은 종단 간 연결성이 보장되지 않는 환경에서의 통신을 위해 메시지 전송 방식으로 "저장 과 운반 및 전달 (Store, Carry and Forward)"을 수행하는 라우팅 방식과 불안정한 네트워크에서 메시지를 전달하기 위해 번들(Bundle)이라는 추가적인 계층을 통해 통신을 하는 네트워크이다. 본 논문은 MIT에서 개발한 Arduino라는 마이크로 컨트롤로 보드와 IEEE802.15.4를 기반으로 하는 Zigbee 통신을 가능케 하는 XBee 모듈을 이용하여 DTN을 구현한 결과를 제시하고 구현된 DTN 환경에서 Relay Node의 속도 변화에 따라 메시지 전달 시간의 변화를 보인다.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.49 no.4
• /
• pp.82-88
• /
• 2012

A VANET (Vehicular Ad Hoc Network), a subclass of MANET (Mobile Ad Hoc Network), is an ad hoc network using wireless communication between vehicles without fixed infrastructure such as base station. VANET suffers a frequent link breakage and network topology change because of the rapid movement of vehicles and the density change of vehicles. From these characteristics of VANET, geographical routing protocols such as GPSR (Greedy Perimeter Stateless Routing) using only the information of neighbor nodes are more suitable rather than AODV and DSR that are used in existing MANETs. However, GPSR may have a transmission delay and packet loss by frequent link disconnection and continual local maxima under the low vehicle density conditions. Therefore, in this paper, we propose a DTVR (Delay Tolerant Vehicular Routing) algorithm that perform a DTN-based routing scheme if there is no 2-hop neighbor nodes for efficient routing under the low vehicle densities in VANETs. Simulation results using ns-2 reveal that the proposed DTVR protocol performs much better performance than the existing routing protocols.

• Journal of information and communication convergence engineering
• /
• v.9 no.6
• /
• pp.625-628
• /
• 2011

Dynamic sensor network(DSN) technology which is based on swarming flight type air node offers analyzed and acquired information on target data gathered by air nodes in rotation flight or 3 dimension array flight. Efficient operation of dynamic sensor network based on air node is possible when problems of processing time, data transmission reliability, power consumption and intermittent connectivity are solved. Delay tolerant network (DTN) can be a desirable alternative to solve those problems. DTN using store-and-forward message switching technology is a solution to intermittent network connectivity, long and variable delay time, asymmetric data rates, and high error rates. However, all processes are performed at the bundle layer, so high power consumption, long processing time, and repeated reliability technique occur. DSN based on swarming flight type air node need to adopt store-and-forward message switching technique of DTN, the cancelation scheme of repeated reliability technique, fast processing time with simplified layer composition.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.4
• /
• pp.1376-1391
• /
• 2015

In bus delay-tolerant networks, the route of bus is determinate but its arrival time is indeterminate. However, most conventional approaches predict future contact without considering its uncertainty, which makes a limitation on routing performance. A novel approach is proposed by employing interval algebra to characterize the contact's uncertainty and time-varying nature. The contact is predicted by using the Bayesian estimation to achieve a better routing performance. Simulation results show that this approach achieves a good balance between delivery latency and delivery ratio.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.6 no.1
• /
• pp.83-90
• /
• 2010

DTNs (Delay Tolerant Networks) refer to the networks that can support data transmission in the extreme networking situations such as continuous delay and no connectivity between ends. DTMNs (Delay Tolerant Networks) are a specific range of DTNs, and its chief considerations in the process of message delivery in the routing protocol are the transmission delay, improvement of reliability, and reduction of network loading. This article proposes a new LCN (Largest Common Neighbor) routing algorism to improve Spray and Wait routing protocol that prevents the generation of unnecessary packets in a network by letting mobile nodes limit the number of copies of their messages to all nodes to L. Since higher L is distributed to nodes with directivity to the destination node and the maximum number of common neighbor nodes among the mobile nodes based on the directivity information of each node and the maximum number of common neighbor nodes, more efficient node transmission can be realized. In order to verify this proposed algorism, DTN simulator was designed by using ONE simulator. According to the result of this simulation, the suggested algorism can reduce average delay and unnecessary message generation.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.4
• /
• pp.13-28
• /
• 2009

Routing protocols in Delay/Disruption Tolerant Networks(DTN) are important to enhance the performance of transmission delay and delivery success ratio. In this paper, we propose an efficient DTN routing algorithm, called "Nobility Pattern based Routing(MPR)", that controls the total number of transferred message copies based on mobility patterns of mobile nodes. We consider a realistic "Levy walk" mobility pattern that has a super-diffusive property which well represents human mobility pattern. We implemented a DTN simulator using ONE simulator for the proposed MPR algorithm and Levy walk mobility pattern. Simulation results show that mobility patterns are very important for accurate evaluation of DTN routing performance, and the proposed MPR enhances the routing performance of delivery delay and success delivery ratio under realistic mobility pattern.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.120-122
• /
• 2015

In this paper, we proposed an algorithm of the unnecessary copied message inhibition using dynamic density what is called DDIM(Dynamic Density-based Inhibited Message diffusion) in DTNs(Delay Tolerant Networks). Existing DTN routing algorithms as Epidemic and Spray and Wait have some problems that occur large overhead in dense network due to the thoughtless message diffusion. Our proposed method, the DDIM, determines adjusted number of copied message through dynamic node density that is calculated using node's radio coverage and neighbor nodes in period time to solve message diffusion problem. It decrease overhead without losing message delivery ratio and increased latency through reducing message diffusion. In this paper, we compare delivery ratio, average latency and overhead of proposed algorithm, DDIM, and existing DTN routing algorithm and prove enhanced performance through simulation results.

• KIPS Transactions on Computer and Communication Systems
• /
• v.5 no.7
• /
• pp.153-158
• /
• 2016

Delay Tolerant Network (DTN) is a network that employed method of store-carry-forward in intermittently connected networks. In DTNs, routing and buffer management scheme are important to improve successful message delivery. This paper proposes an improve spray and wait routing protocol based on delivery probability to a destination. Also, a buffer management scheme is proposed to drop the queued messages according to the number of copies (L value). Simulation results show that the proposed method provides a better delivery ratio and lower communication overhead when compared to existing schemes such as Epidemic, PRoPHET and spray and wait.

• Journal of KIISE:Information Networking
• /
• v.36 no.2
• /
• pp.130-136
• /
• 2009

Delay and Disruption Tolerant Network (DTN) employs message delivery based on a store-and-forward method to conquer no guarantee of continuous end-to-end connectivity. Different from general networks, it is hard for the existing TCP/IP-based routing protocols to correctly work, due to the characteristics such as large latency and unstable link connectivity. Thus, many recent studies focus on routing protocols for DTN. In this paper, we propose a novel routing protocol for DTN with efficient message delivery utilizing mobility information such as direction or destination of mobile nodes. And this protocol is enhanced in terms of delivery ratio, decreases latency and overhead compared to the previously proposed solutions. Simulation results prove its superiority.