使用空間分集技術之無線隨意網路多頻道存取協定之研究

Abstract

許多文獻指出多頻道系統較單頻道系統能提昇系統整體吞吐量，並且考慮無線隨意網路不須基本建設等優點下提出一個結合多通道無線隨意網路之媒體存取協定。本研究主要討論在多頻道無線隨意網路的環境下使用一個控制頻道，數個資料頻道下，在每個節點都配有兩個動態介面下，動態的配置每個節點應該使用的頻道，在相同的傳輸功率下，因為此存取協定允許節點間交換在控制通道上所收到的訊息，使得某些時間內控制通道上的訊息由傳輸對中某一節點收取，再交換給另一節點，讓傳輸對可以在資料頻道上使用空間分集，對抗通道衰減所造成的訊號雜訊比下降，進而使用較好的調變技術增加整體的吞吐量，並且同時設法解決在配有兩個動態介面下多頻道多跳環境下存在的多頻道隱藏節點問題，多頻道聾節點問題與多發送節點競爭單一節點問題。

The previous researches indicated, in the ad hoc network, the capacity and throughput of multiple-channel are better than single channel. Several media access protocols were also proposed to improve the performance. In this study, under the multiple channel ad hoc network, the MIMO technology is deployed to dynamically switch among those channels, common signaling channel and data channels. Once when perform the simultaneously transmitting and receiving together with the capability of access any two channels, either the space diversity or multiple link can be adopted. The space diversity can increase the SNR so as to either decrease BER or increase the transmission speed by switching to high level modulation. In this thesis, the feasibility of combination of MIMO and piggy back scheme is studied to realize the better communication quality(low BER or high throughput). The media access protocol is proposed to avoid the phenomena of expose terminal and hidden terminal. The performance evaluation is also conducted in this study.