隨著無線網路的蓬勃發展，WiMAX都會型無線區域網路的佈建是這幾年最發燒的話題，尤其是實體層採用OFDMA技術的IEEE 802.16e－2005規格將被視為下一代的行動通訊網路。 OFDMA技術支援多個使用者在同個時間點一起分享頻寬發送資料，大幅提高網路的使用者的容量及傳輸的吞吐率。本論文將重點放在訊框分配頻寬給使用者的下行資料時，能夠藉由不同使用者對於子通道有不同的通道品質特性，增加影像語音這類即時服務的資料可使用的訊框空間，並降低非即時服務資料傳送錯誤的機率。另外，考量到DL－MAP可能產生的Overhead，將可提升整個訊框可分配的頻寬資源。 As the wireless network growing rapidly in recent years, the construction of WiMAX metropolitan local network becomes the most popular issue. Especially the IEEE 802.16e－2005 standard, which provides OFDMA technique in physical layer, will be viewed as the next generation communication network. OFDMA technique allows multi-user sharing in the bandwidth and transmitting in the same time, then the network’s capacity and throughput increases drastically. The main idea is to consider that the downlink frames are shared between each user could increase the available slots for rtPS traffic like image and voice data, also decrease the probability of transmitting error for nrtPS traffic because the sub-channel qualities for each user are mutually independent. In addition, it will add the bandwidth’s resource in the frame by checking the overhead which DL-MAP produces.
