透過無線電波傳輸資料所發展的無線傳輸技術已經行之有年。其中以IEEE 802.11所制定的DCF機制最具盛名。然而在傳輸時所帶來的干擾問題以及水下環境中的巨大傳播延遲(Propagation Delay)特性，將使得針對無線電波傳輸所設計的媒介存取控制(MAC)協定，在水下聲波網路中已不適用。本篇論文主要探討在水下使用DCF機制所帶來的干擾問題，以及巨大傳播延遲帶來的隱藏節點問題。透過分析水下聲波傳輸的訊號衰減，提出一套新的運作機制，在考量訊號干擾下，藉以調整封包傳輸所使用的訊號強度，來減少網路上封包的碰撞，進而提升整體網路效能。最後透過實驗模擬，發現本篇論文所提出的運作機制，在網路傳輸效能以及資料傳輸碰撞的表現上有顯著的改善。 Wireless technology has been developed and used for many years. Due to the nature of water, instead of radio wave, sound wave is used for underwater transmission. However, it will waste a lot of time for propagation at every transmission. Recently, IEEE 802.11 DCF is the most famous MAC protocol but is not suitable for underwater scenarios. We figure out the attenuation of acoustic in underwater and interference problem through our analysis. Therefore, this proposal mainly focuses on how to modify the MAC protocol for underwater acoustic network. It can avoid collisions by power control when sending control packets in our proposed protocol. In simulation, our protocol can outperform than other protocols in network throughput and number of collisions.
