IEEE 802.11無線區域網路(Wireless Local Area Networks, WLAN)是目前國內通訊領域最重要的一項產業，不只相關系統出貨量已為全球首位，並且數家IC設計公司也將在今年內推出其核心IC晶片組，完成國內上、下游產業及技術之整合。不過，802.11系統因使用頻帶(2.4G或5.2G頻段)，通訊環境(通常為室內)及傳送功率等限制，使用上最令人詬病的是其傳送距離(Access Point 及用戶間)及傳輸可靠性(影響實際傳送data rate)等問題。

　　本論文的目的即針對 IEEE 802.11 a/b/g系統，研究開發可延伸接取點(Access Point，AP)及用戶(Station, STA)間通訊距離並提高通訊品質的技術及系統設計。本論文研究構想為引進無線橋接器(Wireless Bridge , WB)作為AP及STA間之中繼(Repeater)，其功效不祇AP涵蓋範圍之延伸，並可因STA與WR或AP間距離縮短而提高接收訊號品質，降低干擾，而獲致整體頻譜效益及系統傳輸容量的提升。並且考慮可移動性用戶特性，將系統設計為非通透性以解決Handoff 問題，並提出WB及AP間新的通訊協定，將頻譜作有效利用，更進一步提升系統效能。

　　Nowadays, IEEE 802.11 wireless local area networks (WLAN) related product plays an important role in the domestic communication industry. Not only its productive quantity occupies the first place in the global trade market, but also several local IC design houses have announced to provide the key IC components before the end of this year. It means local industry can take the great advantage of a integration of top- and down-level technologies in the manufacture of WLAN systems. However, WLAN systems usually offer a low throughput due to the problems of long transmission distance and poor communication reliability.

　　The purpose of this thesis is to study and develop a way to solve the problems and to improve the system throughput. The conceptual idea is to introduce a new device, called Wireless Bridge (WB), as the repeater between Access Point (AP) and Stations (STA). The benefits we can get from such design are extension of AP coverage, improvement of spectrum efficiency and system throughput due to shortening the communication distance, etc. We consider the non-transparent WB design to solve the handoff issue of mobile stations. It also comes out a proposal of effective transmission schedule between AP and WB.

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