scholarly journals Probabilistic Routing Based on Two-Hop Information in Delay/Disruption Tolerant Networks

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xu Wang ◽  
Rongxi He ◽  
Bin Lin ◽  
Ying Wang

We investigate an opportunistic routing protocol in delay/disruption tolerant networks (DTNs) where the end-to-end path between source and destination nodes may not exist for most of the time. Probabilistic routing protocol using history of encounters and transitivity (PRoPHET) is an efficient history-based routing protocol specifically proposed for DTNs, which only utilizes the delivery predictability of one-hop neighbors to make a decision for message forwarding. In order to further improve the message delivery rate and to reduce the average overhead of PRoPHET, in this paper we propose an improved probabilistic routing algorithm (IPRA), where the history information of contacts for the immediate encounter and two-hop neighbors has been jointly used to make an informed decision for message forwarding. Based on the Opportunistic Networking Environment (ONE) simulator, the performance of IPRA has been evaluated via extensive simulations. The results show that IPRA can significantly improve the average delivery rate while achieving a better or comparable performance with respect to average overhead, average delay, and total energy consumption compared with the existing algorithms.

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Jianfeng Guan ◽  
Qi Chu ◽  
Ilsun You

The existing spray-based routing algorithms in DTN cannot dynamically adjust the number of message copies based on actual conditions, which results in a waste of resource and a reduction of the message delivery rate. Besides, the existing spray-based routing protocols may result in blind spots or dead end problems due to the limitation of various given metrics. Therefore, this paper proposes a social relationship based adaptive multiple spray-and-wait routing algorithm (called SRAMSW) which retransmits the message copies based on their residence times in the node via buffer management and selects forwarders based on the social relationship. By these means, the proposed algorithm can remove the plight of the message congestion in the buffer and improve the probability of replicas to reach their destinations. The simulation results under different scenarios show that the SRAMSW algorithm can improve the message delivery rate and reduce the messages’ dwell time in the cache and further improve the buffer effectively.


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7847
Author(s):  
Diyue Chen ◽  
Hongyan Cui ◽  
Roy E. Welsch

It is found that nodes in Delay Tolerant Networks (DTN) exhibit stable social attributes similar to those of people. In this paper, an adaptive routing algorithm based on Relation Tree (AR-RT) for DTN is proposed. Each node constructs its own Relation Tree based on the historical encounter frequency, and will adopt different forwarding strategies based on the Relation Tree in the forwarding phase, so as to achieve more targeted forwarding. To further improve the scalability of the algorithm, the source node dynamically controls the initial maximum number of message copies according to its own cache occupancy, which enables the node to make negative feedback to network environment changes. Simulation results show that the AR-RT algorithm proposed in this paper has significant advantages over existing routing algorithms in terms of average delay, average hop count, and message delivery rate.


Author(s):  
Miguel Pinheiro Rodrigues ◽  
Naércio Magaia ◽  
Paulo Rogério Pereira

Delay Tolerant Networks (DTN) are characterized by a lack of end-to-end connectivity. As such, messages (called bundles) can be stored in buffers for a long time. Network congestion can result in poor delivery rates, as bundles are dropped before having a chance of reaching their destination. Some routing protocols, such as MaxProp and Probabilistic Routing Protocol using History of Encounters and Transitivity (PRoPHET), maintain estimations of delivery probabilities for each destination. In this paper, a new drop policy called Largest Bundle’s Hosts Deliverability (LBHD) is proposed that considers all the hosts that received a replica of the same bundle, and their respective delivery probability as estimated by a routing protocol. LBHD uses this additional information to better manage congestion. Simulation results show that LBHD consistently achieves the best delivery probability when paired with PRoPHET and compared with other drop policies proposed in the literature. Also, when paired with MaxProp, LBHD shows the most efficient performance among all the other state of the art policies considering performance metrics such as average delay, overhead ratio and bundle delivery rate. In addition, another drop policy called One Hop Delivery Estimation Drop (OHDED) is proposed. OHDED takes advantage of the encounter predictions of every node in the network stored in every node when using MaxProp. By accurately predicting the bundles that have the highest probability of being delivered directly or in two hops, the results show the best performance in delivery rate and overhead ratio in high congestion scenarios.


2011 ◽  
Vol 22 (4) ◽  
pp. 773-781
Author(s):  
Gui-Ming ZHU ◽  
De-Ke GUO ◽  
Shi-Yao JIN

Author(s):  
Priyanka Bharadwaj ◽  
Surjeet Balhara

Background & Objective: There are some challenging issues such as providing Quality of Service (QoS), restricted usage of channels and shared bandwidth pertaining to ad-hoc networks in a dynamic topology. Hence, there is a requirement to support QoS for the application environment and multimedia services in ad-hoc networks with the fast growing and emerging development of information technology. Eventually, bandwidth is one of the key elements to be considered. Methods: Energy aware QoS routing protocol in an ad-hoc network is presented in this article. Results and Conclusion: The simulation results indicate that the improved protocol outperforms Adhoc On-Demand Distance Vector (AODV) routing protocol in terms of QoS metric such as throughput, packet delivery ratio, loss rate and average delay.


Author(s):  
Zhuofan Liao ◽  
Jingsheng Peng ◽  
Bing Xiong ◽  
Jiawei Huang

AbstractWith the combination of Mobile Edge Computing (MEC) and the next generation cellular networks, computation requests from end devices can be offloaded promptly and accurately by edge servers equipped on Base Stations (BSs). However, due to the densified heterogeneous deployment of BSs, the end device may be covered by more than one BS, which brings new challenges for offloading decision, that is whether and where to offload computing tasks for low latency and energy cost. This paper formulates a multi-user-to-multi-servers (MUMS) edge computing problem in ultra-dense cellular networks. The MUMS problem is divided and conquered by two phases, which are server selection and offloading decision. For the server selection phases, mobile users are grouped to one BS considering both physical distance and workload. After the grouping, the original problem is divided into parallel multi-user-to-one-server offloading decision subproblems. To get fast and near-optimal solutions for these subproblems, a distributed offloading strategy based on a binary-coded genetic algorithm is designed to get an adaptive offloading decision. Convergence analysis of the genetic algorithm is given and extensive simulations show that the proposed strategy significantly reduces the average latency and energy consumption of mobile devices. Compared with the state-of-the-art offloading researches, our strategy reduces the average delay by 56% and total energy consumption by 14% in the ultra-dense cellular networks.


2014 ◽  
Vol 651-653 ◽  
pp. 1868-1874
Author(s):  
Li Zhu ◽  
Lan Bai

VANETs is a rapid developed wireless mobile MANETs network with special challenge nature. It is a distributed and self-organized communication network based on moving vehicle. This network has characteristics like limited bandwidth, strong mobility, strong dynamic network topology, limited node degrees freedom, equipment capacity constraints and weak physical security. These characteristics usually make typical routing protocol in mobile MANET show a low efficiency in mobile VANETs, even fail. MANET routing algorithm is roughly divided into two categories, namely table driven routing protocol and on-demand routing protocol. It is due to the particularity of driving cars on the road. So how to improve network routing protocol in the performance is now a challenging problem. The purpose of this article studies network routing mechanism based on wireless vehicular networks simulation method. On the basis of analyzing the performance of typical routing protocols in MANET, such as DSDV, AODV and DSR, the improved scheme of AODV on-demand routing algorithm is put forward.


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