於無線網路環境下多媒體資料傳輸之頻寬保留機制

Bandwidth Reservation Scheme for Multimedia Data Transmission in Wireless Network

胡程偉(Cheng-Wei Hu)

指導教授 ： 王振興 ； 王永鐘

國立臺北科技大學/機電學院/電機工程系所/碩士(2006年)

摘要

隨著網際網路的蓬勃發展，網路使用者與日遽增，為了達到可移動性之網路服務與提昇多媒體資料傳輸之服務品質，因此無線網路的基礎建設亦須不斷地擴充。又為了讓移動中的使用者不因位置的遷移而中斷連線中的服務，負責訊號傳輸之基地台間必須保有服務涵蓋區重疊的部份。本論文乃利用允入控制(Connection Admission Control, CAC)機制，依連線服務等級的不同動態地調整預留頻寬數；另提出一套提早換手機制，將重載狀態下的基地台的部份工作，提早由鄰近的基地台承擔，以降低新呼叫堵塞(call blocking probability, CBP)與交遞失敗率(connection dropping probability, CDP)，同時提升無線網路資源的使用率。 本論文利用NS2模擬真實之無線網路環境，其中包含多個網路基地台的建置、隨機產生新連線的使用者與移動中的使用者、與隨機提出即時性或非即時性之服務需求。經模擬驗證，本論文所提出之提早換手機制確能有效的提升無線網路資源之利用率。

關鍵字

允入控制 ； 頻寬預留

並列摘要

Followed by the rapid development of the Internet, the population of network users is increasing tremendously. To achieve the mobility for network services and to promote the service quality for multimedia data transmission, the infrastructure of wireless network is also need to be expanded continuously. The undergoing services won’t be ceased caused by the users’ move if there are overlapping areas among base stations. This thesis adopts Connection Admission Control mechanism dynamically reserving channels for different services according to their service priority. In addition, we propose an early handoff scheme which can unload part of jobs from heavy loaded base station to its neighbors in order to lower its call blocking and connection dropping probabilities and to heighten the resource utility rate of wireless network.
This thesis chooses NS2 to simulate real wireless network environment, in which multiple base stations have been built up, new connection calls for new coming users and handoff calls for moving users have been generated randomly, and real-time as well as non-real time services have also been randomly presented. After simulation and verification, the early handoff scheme we proposed can really boost the resource utility rate of wireless network.

並列關鍵字

CAC ； bandwidth reservation

參考文獻

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