Research And Application Of Routing Protocol In Pocket Switched Network

In recent years, Pocket Switched Networks(PSN) is a new concept attracting extensive attention in field of wireless delay-tolerant network research; it refers to the communication delay network taking portable wireless mobile device as orientation and human as theme in general, which is a major branch of delay-tolerant network and identified as a key technology to realize “human-oriented pervasive mobile computing”. Especially in scene without complete communication facilities(such as rescue after disaster, secluded mountain area, etc.), PSN has been widely used in data collection, integration, transmission, etc. However, due to the dynamic and changeable communication link between intelligent devices in PSN, it is crucial to design reasonable routing model and determine appropriate message transmission path in a relatively stable people-to-people network so as to effectively transfer message to destination, which is of great importance for ensuring the reliability and safety of data transmission in PSN.PSN is essentially a kind of delay-tolerant network; therefore, research on routing problem of PSN is closely related to properties of network itself. Compared with other types of delay-tolerant network, device carrier of PSN is people, and its moving regulation of communication node follows that of human society, thus, PSN is closely related to social network theory of human social relations. The research emphasis of this thesis focused on solving the following problems:(1) the influence of social networking features of PSN on construction of routing model;(2) high-performance routing model based on social network;(3) how to use the PSN routing model to solve practical problems. Specifically, the research work of this thesis mainly included the following aspects:Firstly, according to existing relevant literature, this thesis deeply researched the development direction of this field. On the basis of theoretical basis applied, the author divided existing relevant theoretical models into three categories: modeling theory based on centrality analysis and influence, theory based on community evolution pattern and dynamic community mining technology and theory based on behavioral signature technology, and analyzed their deficiencies by combining with relevant social network theory respectively. Then, the author initially elaborated the feasibility of behavioral signature technology in constructing high-performance routing protocol and the development trend of the field researched in this thesis.Secondly, this thesis researched how social network properties of node in PSN affect routing model performance. The author proposed routing protocol model based on parameter adaptive, comparatively analyzed the difference between PSN and general wireless delay-tolerant network, characteristic of PSN itself, the particularity of node in PSN different from the general wireless delay-tolerant network, common characteristic between PSN and social network, etc., and conducted research and discussion on core problems of PSN needing attention in the process of research, the reasons for poor suitability of routing protocol model of wireless delay-tolerant network for PSN, the subsequent basic research ideas, etc.Thirdly, the thesis studied the reasonable construction of routing model based on social network attributes of PSN nodes. In PSN, the social network attributes of nodes would impact the performance of routing model. Based on the aforesaid theory and combined with the truthful dataset, this thesis conducted contrastive analysis of impact of different attributes on information transmission capacity of nodes, analyzed the routing strategy's disadvantages of existing model, and reached the corresponding conclusions concerning structure and connectivity of social network as well as transmission efficiency of network packet; furthermore, on the basis of combination of overall and partial situation, the thesis took advantage of social network attributes of nodes in the network to construct a reasonable routing strategy to form a complete model of routing protocol; at last, the thesis carried out simulation verification of this model. As for comparison between simulation result and that of other algorithms, the thesis analyzed the differences in performance of different algorithms in detail and explained the reasons for such difference.Fourthly, the thesis made an attempt to apply the concept of PSN routing model to other practical problems. To be specific, the thesis selected express parcel allocation based on crowdsourcing system as representative of practical application, which, compared to traditional wireless delay- tolerant network scenarios, can better reflects PSN's features and therefore is of great practical value and promising application prospect. The thesis abstracted the process of crowdsourcing-system-based express parcel allocation as PSN routing process and predicted the location of node at a certain future time point according to its own moving pattern in the crowdsourcing express parcel network; on this ground, the thesis put forward the routing protocol model based on mobile interaction. The comparison result shows that the algorithm proposed in this thesis is superior to other algorithms; in addition, the thesis analyzed the shortcomings of the proposed algorithms. Behavioral signature is a technology that can predict the behavior trace of a node at a certain future time point according to its own moving pattern and then determine the encounter of nodes; therefore, the routing protocol model put forward in this thesis can be regarded as a specific application of behavioral signature in PSN routing, which is also the ultimate research objective of this thesis.Finally, the author roundly summarized the research work of this thesis, summarily explained the main research content of this thesis, summarized the theoretical basis and experimental methods involved, and clearly pointed out the existing deficiencies therein. Then, aiming at the deficiencies above, the author raised follow-up work focus and the expected improvements of this research, trying to apply the research conclusions into the broader practical applications.