無線網路提供使用者一個無遠弗屆的通訊環境，讓使用者可以隨時隨地存取資訊而不受到位置的限制。在傳統的蜂巢式無線網路系統中，系統需要許多固定式基地台，並且利用有線骨幹將這些基地台互相連接。行動使用者的通訊，完全依靠基地台與有線骨幹的傳輸。 相對於蜂巢式系統，無基地台式無線網路系統並不須要任何的中控者 (如:基地台) 與有線骨幹。系統是由許多行動使用者自動形成一個暫時的網路架構，所有的通訊都依賴此網路架構。因此，無基地台式無線網路系統特別適用由特殊的情況下，例如: 戰爭中的通訊、災難救助等等。 現今許多無線網路系統已開始支援多媒體傳輸，例如:GPRS與三代通訊系統。但是，由於無基地台式無線網路系統中，並不存在任何的中央控制者與傳輸骨幹。因此，相對於蜂巢式網路，此系統較難在系統中提供效能保證與多媒體傳輸。 此篇論文中，我們提出在無基地台式網路架構下，支授服務品質保證與多媒體傳輸的方法。相關的機制包括: CSMA/CA媒介存取方法、預約機制與具服務品質資訊的路由協定。經由相關機制的運作，系統將動態的分配相關資源給行動使用者，並提供相對應的服務品質保證。 Wireless networks provide mobile users with ubiquitous communicating capability and information access regardless of user location. In the traditional cellular wireless network system, it requires fixed base stations that are interconnected by a wired backbone. Communications between two mobile users completely rely on the wired backbone and fixed base stations. In contrast with cellular system, an ad hoc network is a collection of mobile stations forming a temporary network without the aid of any centralized coordinator. It is useful for some special situations, such as battlefield communications and disaster recovery. Many wireless systems try to support multimedia transmission nowadays, such as GPRS and 3rd generation wireless system. However, since the ad hoc network has no central controller and communication backbone, it is more difficult to provide performance guarantee for multimedia transmission than cellular network. In this thesis, we propose an approach to support QoS for multimedia applications in ad hoc wireless network. The approach we provide uses CSMA/CA medium access protocol and additional reservation and control mechanisms to guarantee quality of service in ad hoc network system. The reason we choose CSMA protocol instead of other MAC protocols is that it is used in most of currently wireless LAN productions. Via QoS routing information and reservation scheme, network resources are dynamically allocated to individual multimedia application connections.
