臺灣博碩士論文加值系統

在這篇論文裡，首先描述了現今已存在的細胞式通信系統，接著在第二章
，我們經由數學分析和電腦模擬探討了一種被提議使用於未來系統的封包
預約式多重介入 (Packet Reservation Multiple Access, PRMA) 規約。
此種新提議的規約是藉由抽出在傳統 TDMA 系統裡正處於靜音狀態的使用
者來增加系統容量，研究結果顯示 PRMA 的系統容量為傳統 TDMA 的
1.64 倍。因為 PRMA 在高負載的情況下，其預約能力驟降至零而有系統
不穩定的現象，所以我們提出一種無碰撞封包預約多重介入 (Non-
Collision PRMA, NC-PRMA)規約來解決系統不穩定的問題，並經由數學分
析和電腦模擬去探討此種規約。在 NC-PRMA 系統裡，每一個細胞有一個
專用為建立呼叫及系統維護的控制頻道，而在資訊頻道每一個碼框，配置
有專用於封包預約程序的預約時槽，因此在資訊頻道上並無封包競爭現象
，而封包碰撞也不再發生。由研究結果顯示 NC-PRMA沒有系統不穩定的問
題，且其系統容量可提高為傳統 TDMA 的 1.73 倍。在第四章中我們探討
了捕捉機構 (Capture Mechanism)對 PRMA 的影響，結果顯示對解決不穩
定的問題，使用捕捉機構也是個極為有效的策略。雖然有些研究顯示分碼
多重介入 (Code Divis on Multiple Access, CDMA) 技術對用於未來系
統而言有其理論的優點，但基於商用及實作考量的觀點，TDMA形態的封包
預約多重介入技術也是值得被考慮用於未來系統的頻道介入技術之一。

A Packet Reservation Multiple Access (PRMA) provided for future
system is studied in thesis, both analysis and simulation are
presented and discussed. The study results show that the PRMA
can enhance the system capacity by a factor of 1.64 than that
of the conventional TDMA system. Since the PRMA has an unstable
phenomenon in heavy load condition, in which the reservation
capacity will shrink to zero, we propose a modified version of
PRMA, called Non-Collision PRMA (NC-PRMA), to resolve the
unstable problem; both analysis and simulation are also
presented. According to the study results we have realized that
the NC-PRMA has not any unstable problem and has a higher
system capacity than PRMA does, 1.73 times that of conventional
TDMA system. Finally, we also study the effect of providing a
capture mechanism to PRMA. The results reveal that the capture
mechanism is also an effective and powerful strategy to resolve
the unstable problem. Although some studies show that the Code
Division Multiple Access (CDMA) technique has a lot of
theoretical advantages for the future systems, In
consideration of commercial and implemented aspects, the
packet reservation protocols based on TDMA techniques are
worth being considered for the future system.