IEEE 802.11ad無線通訊系統可提供Gigabit (Gbps)的資訊傳送率。由於運作於60GHz毫米波通道，此系統是採用指向性天線以增長通訊距離、降低傳播延遲，並在適當MAC協定設計下，更提高整體吞吐量(Throughput)。但在用戶資訊傳送前，首需面對傳送/接收端天線波束對齊的溝通協調問題，尤其通訊用戶具移動性時更為困擾；本論文針對IEEE 802.11ad標準系統，在Association Beamforming Training (A-BFT)區間及Contention-Based Access Periods (CBAP)區間內，提出不同協定加以改善。執行Sector Level Sweep (SLS)階段的A-BFT區間內，傳送端(STAs)波束對齊訓練(BF training)競爭所發生的碰撞問題，我們讓傳送端根據自己所在的sector用戶多寡，進行倒退(Backoff)值的適應性調整。在CBAP區間內，因接收端(PCP/AP)與傳送端(STAs)皆透過指向性天線傳送RTS及CTS會產生聾耳(Deafness)問題，我們將CTS從指向性傳輸變成全向性傳輸，藉此改善因聾耳造成沒必要的延長時間傳輸。模擬結果顯示，相較於IEEE 802.11ad系統目前標準規範，我們所提的方法可以提升波束對齊訓練的成功率及資料的吞吐量。

IEEE 802.11ad wireless communication systems can provide Gigabit (Gbps) transmission. Since this system operates at 60 GHz millimeter wave channel, its data transmission adopts the directional antenna to increase communication distance and reduce propagation delay. The throughput can also be improved with appropriate MAC protocol. However, before the stations transmit the information, beamforming (BF) training between the transmitter and receiver must be processed, especially for the stations with mobility. In this thesis we propose different protocols to improve the efficiency during Association Beamforming Training (A-BFT) and Contention-Based Access Periods (CBAP) intervals for IEEE 802.11ad. The A-BFT phase suffers high probability of collisions when the STAs compete for the channel. To solve this problem, we let the STAs backoff adaptively according to the number of STAs in each sector. In order to reduce the deafness problem in the CBAP interval, we propose that the CTS is transmitted in Omni-direction. The simulation results show that the proposed methods can improve the success rate of BF training and increase the system throughput.

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