乙太被動光纖網路是目前廣受歡迎的光纖接取網路架構，上傳採用時間分割多工(Time Division Multiplexing；TDM)的方式，而在乙太被動光纖網路上較為所推薦的動態頻寬分配演算法為適應式週期時間交錯式輪詢法(Interleaved Polling with Adaptive Cycle Time; IPACT)。
　　在IPACT中最為普遍使用的有Gated與Limited兩種服務的類型，本文考慮有較低的封包延遲之Gated IPACT方法，針對其報告訊息傳輸位置對週期時間與封包延遲之影響，我們定義出兩種效率負載，分別是高效率負載與低效率負載，導出在不同的效率負載下平均封包延遲時間之值，依據此值分析能達到最小化平均封包延遲時間之報告訊息位置選擇策略。
　　另外，我們設計了一個能夠動態尋找報告訊息位置的機制，光纖線路終端在每一次接收報告訊息時估計光纖網路單元負載的記錄，光纖線路終端再以目前所估計之負載，依據我們所推出的訊息位置選擇策略來決定出適合的報告訊息位置。
最後我們以Poisson和Self-similar 的封包產生型態來模擬實際的封包延遲改善率，以動態尋找報告訊息位置機制與固定於前方或後方之方法比較，皆有較低的封包延遲時間。在我們的模擬中實作了光纖網路單元個數為16與8的情形，其中光纖網路單元個數為8且為均勻負載時，在Poisson的封包產生型態下，對固定於後方與前方之傳輸方式之改善的比例分別最高為3.4%(總負載為0.55)與7.3%(總負載為0.95)；而在Self-similar的封包產生型態下，對固定於後方與前方之傳輸方式之改善的比例分別最高為8.6%(總負載為0.4)與2.6%(總負載為0.7)。

Ethernet passive optical networks (EPONs), which use time division multiplexing for upstream channel, have become the most popular architecture for the optical access networks. Interleaved polling with adaptive cycle time (IPACT) dynamic bandwidth allocation algorithm is proposed to use for EPONs.
There are two universal types of service which are gated and limited services in IPACT. In this thesis, we focus on gated IPACT which has lower average packet delay than the other. According to the influence of report position on cycle time and packet delay, we define two efficiency loadings, i.e. high and low efficiency loading, and we propose the report position strategy which has the smallest average packet delay under these two efficiency loadings.
Additionally, we design a fitting report position (FRP) scheme for Gated IPACT based on the proposed report position strategy. In the optical line terminal (OLT), it estimates the average load in each optical network unit (ONU) for every receiving report message and determines the fit report position depending on estimated load.
In our simulation results, we perform the relative reduction of the proposed FRP scheme comparing with two fixed report position policies which are reporting at the front and the end of the transmission window in delay with Poisson and Self-similar traffic types. The proposed FRP scheme has lower packet delay than these two fixed report position policies. For an EPON with eight ONUs and uniform traffic load, the relative reductions of the proposed FRP scheme comparing with reporting at the front and the end of the transmission window in delay are up to 3.4%(load=0.55) and 7.3%(load=0.95) with Poisson traffic, respectively; the relative reductions of the proposed FRP scheme comparing with reporting at the front and the end of the transmission window in delay are up to 8.6%(load=0.4) and 2.6%(load=0.7) with Self-similar traffic, respectively.

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