無線同儕對同儕式移動偵搜網路服務之架構設計

Architecture Design of a Peer-to-peer Mobile Video Surveillance Service on Wireless Network

廖祐楷(Yu-Kai Liao)

指導教授 ： 張時中

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01952

摘要

摘要

影像偵搜系統已廣泛使用於保護人身以及公共安全的應用上。隨著以IP為基礎的網路和以IP為基礎的偵搜網路的興起，新型態的偵搜網路應用也將因此蓬勃發展。除此之外，在近幾年同儕式（P2P）網路以及無線通信技術已發展成熟而且可以實際應用於檔案分享和影像串流分享。這些技術的結合促成移動式偵搜網路應用的可能性。

本論文的研究中，我們提出一個創新的移動式偵搜網路，在這個應用中我們整合IP技術、移動式攝影機技術、無線通信技術以及同儕式(P2P)網路技術。
假設各個移動通信節點可取得所在的定位資訊，則我們利用同儕式(P2P)網路技術中的節點搜尋技術來搜尋特定位置附近的電腦(peer)，接著利用移動式偵搜裝置（例如筆記型電腦結合攝影機、相機手機、車用偵搜系統）取得特定位置的影像，最後在利用覆蓋(overlay) 點對點層在IEEE 802.11 為基礎的無線網路上來提供行動點對點偵搜影像串流傳輸服務。

為了提供點對點影像串流分享服務，需要克服的挑戰如下:
1. 如何在IEEE 802.11無線通訊的移動網路環境上覆蓋（overlay）P2P 層。
2. 如何定位出主機(peer)自身的位置以及如何把已取得位置資訊利用無線通信發送給鄰近的主機(peer)。
3. 如何搜尋特定點附近的主機（peer）並且建立一條可以傳送影像串流的路徑。

針對上述三項挑戰，我們在點對點層設計三個基本的服務及兩個輔助功能
如下:
a. 連線和上傳位置資訊服務:
連接到別的使用者並提供自己的位置資訊還有影像分享的埠(port)而取得被連接使用者的分享資訊。
b. 影像交換服務:
利用瀏覽器從特定的埠(port)接受影像資訊或發送自己的影像供其他使用者瀏覽。
c. 搜尋服務:
我們提出最短路徑搜尋的演算法來找到特定取像點附近的使用者並且紀錄傳輸路徑。
d. 察覺功能
我們設計“察覺功能”來感知周圍的使用者並且取得使用者的IP位址。
e. 路徑功能
我們設計“路徑功能”用來紀錄搜尋結果並且建立傳輸路徑。

藉由上述的連線和上傳位置資訊服務及察覺功能可以解決挑戰一和二所面臨的問題，利用搜尋服務、影像交換服務、路徑功能則克服挑戰三所面臨的問題。

最後，我們針對所設計的架構並利用VB.NETTM和Visual C#TM 開發一個簡易的系統雛型。雛型中包含「連線和上傳位置資訊服務」、「影像交換服務」、「搜尋服務」以及「察覺功能」、「路徑功能」。在這個系統中，可以達成在無線隨意網路(wireless ad hoc network)點對點影像分享的功能

關鍵字

無線 ； 同儕對同儕式 ； 移動偵搜網路

並列摘要

Abstract

Video surveillance system has been widely used to protect personal and public security. With the IP-based networking and IP-based video surveillance environments emerging, new video surveillance applications are inspired. In recent years, the peer-to-peer (P2P) network and wireless communication technologies have also been mature for file sharing and video stream sharing services. The combinations of these technologies push through the possibility of mobile video surveillance application.

Motivated by these technological advancements, we explore new and innovative video surveillance services that exploit the integration of IP, mobile, wireless and P2P network technologies. For example, we can apply P2P searching technology to discover peers which are near desired position. Then we can utilize mobile video surveillance (e.g. notebook PC mounted webcam, camera mobile phone, in-car video surveillance) to do video image capturing in a desired position. Finally, we use the advanced wireless transmission technology to transmit the video stream. In this research we shall focus on the desired position video stream capturing and transmission service. We shall overlay P2P layer on the existing IEEE 802.11- based wireless network to do peer-to-peer mobile video surveillance network (P2P MVSN) service.
In order to provide the service, there are challenges as follows:
1. How to overlay P2P layer on IEEE 802.11 WLAN.
2. How to do peer location positioning and send the position information to neighbor peer through wireless communication.
3. How to do specific peer searching service and construct routing path between requester and destination.
In view of the challenges of P2P MVSN service, we propose a new and innovative architecture design. In our architecture design, we overlay P2P layer on the existing IEEE 802.11- based wireless network. To solve the challenges mentioned above, we design three basic services and three auxiliary functions in P2P layer.
a. Connect and upload service:
The service let a peer connect to other peer and provide his position information and sharing port in order to retrieve the same information from connected peer.
b. Exchange service :
The service let a peer to receive video stream among webcam from other peer in specific port and send his video stream to other peer in specific port.
c. Lookup service :
In order to do specific position video stream capturing service, we design “Lookup service” to find a peer near desired position and record the routing path. The shortest path method is proposed to do peer searching.
d. Awareness function: to sense the existence of neighbor peer.
e. Routing function: to record the path from source peer to destination peer.
By utilizing “Connect and upload service” and “Awareness function”, we solve the challenge 1 and challenge 2. And we exploit “Lookup service,” “Routing function,” and “Exchange service” to solve challenge 3.

Finally, we implement a system prototype including Connect and position upload service, Exchange service, Lookup service, and awareness function. We use the Visual C# TM to develop ASP web service, and use VB.NET TM to develop user interface panel in the implementation. In addition, we build SQL TM database to store neighbor peer’s IP address, position, and sharing port.

並列關鍵字

Peer-to-peer ； Mobile ； Video Surveillance Service ； Wireless Network

參考文獻

[PAT] California PATH, “Traffic Surveillance,” (http://www.path.berkeley.edu).

[Agg04] G. Aggelou, Mobile Ad Hoc Network: Design and Integration, New York: McGraw-Hill, 2004.

[CCL03] I. Chlamtac, M. Conti, Jennifer J.-N. Liu, “Mobile ad hoc networking: imperatives and challenges,” Ad Hoc Networks, v 1, n 1, July, 2003, pp.13-64.

[CWK97] B. P. Crow, I. Widjaja, J. G. Kim, P. T. Sakai, “IEEE 802.11 Wireless Local Area Networks,” IEEE Communications Magazine September 1997, pp.15-18.

[DDM03] D. Doval, D. O ‘Mahony, “Overlay networks: A scalable alternative for P2P,” IEEE Internet Computing magazine 2003, pp.34-37.