第三代行動通訊發展至今，Wideband CDMA(WCDMA)為其中廣受看好的一項air 端介面控制存取技術標準，在當前的3GPP release 99，第三代行動通訊傳輸速率能達到384Kbps 至2Mbps。不過科技在進步，人的需求在增加，WCDMA Evolved 成為大家致力的目標，描述如何使終端的使用者能有更好的品質和簡化，系統能達到更有效率和更大的負載量。適應性調變編碼技術(AMC)能根據當前的通道狀況和系統限制，使用適合當前環境的調變和編碼，在UE 通訊情況好時，AMC 分配高等級和高速率的編碼給這個UE，反之則使用低等級和低速率的編碼，達到提升速率和節省能源。而如何依據當前的通道狀況和系統限制，使用適合當前環境的調變和編碼，就是一個重要的問題。我們提出一個簡單的方式，來使得系統能夠使用適合當前環境的調變和編碼，提高傳輸量和縮短延遲時間。實驗結果顯露出我們提出的方法的確可以在第三代行動通訊網路下有效地使效能顯著的提升。 With the development of 3G, today the Wideband CDMA (WCDMA) is a widely accepted air interface technique. The WCDMA 3GPP Release99 provides data rates of 384 Kbps for wide area coverage and up to 2 Mbps for hot-spot areas. But the more we demand when technique has progressed.WCDMA Evolved had brought up, which describes the evolution of WCDMA addressing both operators need for efficiency and end-users demand for enhanced experience and simplicity. Adaptive modulation and coding (AMC) is a radio link adaptation technique where the modulation level and coding method are varied according to the channel quality, the higher quality of UE can be served with higher modulation level and faster coding rates, such as 16QAM and 3/4 rate, to achieve higher peak rates. On the contrary, lower quality of UE can be served with lower modulation level and slower coding rates, such as QPSK and 1/4 rate. How to according to the channel quality and select suitable Adaptive modulation and coding is very important thing. we proposal a simple way to according to the channel quality and select suitable Adaptive modulation and coding. And then, the throughput became higher and delay became shorter. Simulation experiments reveal that our scheme gives prominence to improve performance effectively over 3G networks.
