無線多載波分碼多工系統之寬頻多速率通訊

多載波分工傳輸和分碼多工接取是兩個在無線頻選衰退通道中相當被看好的傳輸技術，本論文研究藉由兩者的結合，也就是多載波分碼多工傳輸，來支援未來傳遞於無線寬頻通道的多媒體通訊傳輸。在本論文中利用多碼與可變展頻的概念提出了兩個多速率多載波分碼多工傳輸方法，也同時研究其相關的系統議題，例如如何達成有效的接收。本論文中提出了數個可支援多碼及可變展頻雙模式接收的多用戶檢測法來解決多載波分碼多工本身在上鏈通道中自然產生的正交失真問題，此問題的解決使得多碼與可變展頻的多速率多載波分碼多工傳輸能夠在上鏈通道中獲得有效的接收。此外，要讓系統在多媒體通訊應用時能夠擁有高效率的資源配置，亦針對相關的傳輸速率、功率、以及所使用的子載波提出分配方法，藉由這些資源分配方法，除了可使得各傳輸中的用戶或服務的品質及效能得到保證外，更使得整體的功率消耗能達到最小化。另外，由於行動接收在未來的無線通訊系統中是一個相當關鍵的挑戰，因此提出了一個能抵抗行動通道中都普勒效應的接收方法以增強多載波分碼多工系統在行動多媒體應用時的效能。最後，建構了一個可重組化的系統架構，不僅僅能作為分碼及可變展頻雙模混合接取多載波分碼多工的可程式化平台基礎，更能在此架構下整合他種主要的正交分頻分碼多工系統，以一個軟體無線電的系統架構模式，來提供硬體運作的可適應性，增加本身的系統可適多樣性以達成跨系統不中斷通訊接取的目標。

關鍵字

多載波分碼多工；正交分頻分工；分碼多工；多速率多重接取；多速率傳輸；多用戶檢測；無線電資源配置；可重組化系統架構

並列摘要

Multi-carrier multiplexing and Code-Division-Multiple-Access are two promising signaling technologies in wireless frequency-selective-fading channels. In this dissertation, their combination, Multi-Carrier CDMA (MC-CDMA) transmission, is studied to support wireless multimedia communications in broadband wireless channels. Two multi-rate MC-CDMA transmission schemes based on Multi-Code (MC) and Variable-Spreading-Length (VSL) concepts are proposed and the related system issues and reception problems are investigated. Multiuser detections supporting MC/VSL dual mode receptions are proposed to solve the inherent distortion of spreading code orthogonality in uplink channels due to spread spectrum over multiple carriers, which yields effective reception of MC/VSL MC-CDMA for uplink applications. To optimize the efficiency of radio resource utilization in multimedia applications, the allocations of transmission rate, power, and sub-carriers are investigated to minimize the total power consumption and practical allocation algorithms are proposed. Since mobility is a critical challenge of future wireless communication systems, a reception technique that enhances the reception performance of MC-CDMA against Doppler Effect in mobile channels is applied to improve the capability of mobile multimedia transmissions. Finally, a re-configurable system architecture is constructed, which not only leads to a programmable platform capable of MC/VSL hybrid MC-CDMA access but also promises system integration with various major OFDM-CDMA systems as Software Define Radio to provide hardware adaptation for system diversity toward seamless communication access. The design and direction to future wireless multimedia communication systems are investigated in this dissertation.

並列關鍵字

Multi-Carrier CDMA ； OFDM ； CDMA ； Multi-Rate Multiple Access ； Multi-Rate Transmission ； Multiuser Detection ； Radio Resource Allocation ； Reconfigurable System Architecture

參考文獻

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無線多載波分碼多工系統之寬頻多速率通訊

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