正交分頻多重擷取系統之動態模擬平台

Abstract

在各式新一代無線通訊系統的設計中，正交分頻多工(Orthogonal Frequency Division Multiplexing , OFDM)技術由於具備良好抵抗多路徑衰落(Multipath Fading)的能力與較高的頻譜使用效率，被視為未來系統必備的主流核心技術。由於結合正交分頻多工技術的系統對於無線資源耗用的形式與以往的系統截然不同，且目前正有多種結合正交分頻多工之多重接取(Multiple Access)技術概念在發展，因此如何設計出能滿足各種服務要求的系統架構，並發展出適合之無線資源管理技術是新一代無線通訊系統發展正面臨的挑戰。在本研究中，一個適合以正交分頻多工技術為基礎之無線通訊系統模擬平台雛型已開發完成，除了包含系統環境之效應如使用者移動效應、通道效應、資料流量變化等等之外，還包含了已初步開發之無線資源管理演算法如允入控制、通道分配、功率分配、功率控制、換手技術與封包排程。除此之外，在系統模擬軟體的開發上，亦發展出一套創新且具有彈性的技術可大幅降低模擬進行時所需耗用之硬體資源。這些研究成果都將成為本研究後續進行時的良好基礎。 為了大幅增加本研究成果的實用價值，系統架構在設計時參考了目前IEEE 802.16a標準小組在開發無線都會型廣域網路(Wireless Metropolitan Area Network)的設計考量，以發展各種實用可行之技術。

Orthogonal frequency division multiplexing (OFDM) is well recognized as one of the core technologies for next generation wireless communication systems due to its robustness against multipath fading and higher spectrum efficiency than the single-carrier systems. A vast volume of research has been directed to physical layer design of OFDM multiple access systems, but only very few have been devoted to the study on the system level, including radio resource management of the systems. In this thesis, an OFDM-based simulation platform is developed for multi-cell, multiple access environments. Realistic system parameters such as user mobility, channel fading, and data traffic have been implemented in the simulations. Effective RRM algorithms such as admission control, channel assignment, power allocation, power control, handover and packet scheduling all have been embedded in this platform as well. In addition, a novel and flexible simulation technique is developed for substantially reducing simulation complexity. This simulation platform provides a good foundation for future RRM research on OFDM-based multiple access systems.