應用於無線感測網路的服務搜尋機制

Abstract

無線感測網路是由一群具備有限能源、計算以及無線通訊能力的感測器動態形成的網路，感測器間的通訊是藉由網路間鄰近的感測器相互傳遞資料、交換訊息而完成。無線感測網路的應用大都於傾向於感測資料之蒐集、聚合與傳送，而搜尋特定感測資料的服務搜尋目前正逐漸受到重視。現行的服務搜尋機制大多屬於集中式的目錄服務伺服主機或是進行網路廣播；感測器因能力之限制無法擔任伺服主機之角色，且利用廣播來查詢服務亦將影響網路頻寬與能源消耗。本篇論文針對無線感測網路上之服務搜尋機制提出一個分散式的解決方案。運用快取機制預先紀錄與感測器相鄰的鄰居及其所提供的服務，運用K-Hop服務搜尋演算法進行服務查詢，可降低服務查詢時傳送之訊息數量，降低對感測器之影響。

Wireless sensor network is composed by a large number of dynamic sensors with limited energy, computation and wireless communication, the communication between each sensor is performed by sending and forwarding message of the neighboring sensors within the network. The applications of the sensor network largely trends to collect, aggregate and forward the sensed information, especially, the service discovery of specific sensor data is receiving increasingly interest. The most service discovery protocols are focused on centralized Directory Server or network broadcast. However, sensors are not able to play the role of server because of the limited capability, and lookup service by using broadcast will also influence network bandwidth and energy consumption. This thesis is to propose a decentralized solution of service discovery protocol for wireless sensor network. Lookup service performed by the proposed K-Hop service discovery algorithm with cached mechanism for previous cached record and the provided services of the neighboring sensor can reduce the forwarding message numbers and reduce the influences of sensors.