在一個多用戶的電力線通訊(PLC)家用網路中，存在著許多方法去決定哪一個使用者擁有權力使用通道並傳送資料。基本上，大致上可以分成兩種機制: 協調式與競爭式。在協調式的機制中，電力線通訊網路的管理者，我們稱之為domain master，將會根據使用者的需求以及現在網路中的可用資源，來安排使用媒介給使用者。至於另一種機制，競爭式，所有想要使用通道的使用者，會彼此競爭使用通道的權力，從競爭中獲勝的使用者，便能使用通道去進行傳輸活動。在本篇論文中，為了改良整個系統的吞吐量，我們提出了一種自適性MAC層協定，能夠藉由使用者的延遲情況與現在通道的狀況來調整數據傳輸速率與競爭時框的大小。在本篇論文中，我們另外提出了一個定理，證明雖然我們所提出來的協定能夠確實改良原本的電力線通訊家用網路系統的吞吐量，但改良後的吞吐量還是有其上限存在。從模擬的結果可以看出，我們提出的協定比起以往的協定，能夠提升系統45 %的吞吐量。

In a multi-user power line communication (PLC) home network, there are several methods to decide who has the right to use the channel to send data. Basically, there are two kinds of scheduling schemes: coordinated and contention-based. For coordinated scheduling scheme, the manager of PLC network, called domain master, will arrange available medium for users according to network resources and users' requirements. The other scheduling scheme, called contention–based, is that users contend for the medium in a transmission opportunity (TXOP) and the user who wins the contention can transmit a data frame or a data frame sequence. In this paper, we propose an adaptive MAC protocol by adjusting data rate and contention window size based on users' defer situations and channel conditions to improve the system throughput. We provide a theorem to show the limit of throughput achievable by the proposed system and perform extensive simulation to verify that the proposed MAC protocol can indeed improve the system throughput by 45 % in PLC home networks.

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