多速率多頻帶混合多載波/多載波-直序展頻之分碼多工用於超寬頻傳輸

最新的無線個人區域網路標準802.15 3a採用超寬頻技術來傳輸多媒體資訊。因應其高且多重速率的要求，促使我們考量如何在已開放的頻寬中作規劃。而多頻帶傳輸被視為可降低硬體複雜度的方法之一，並它同時充釵U種多重存取系統架構於其夠寬的子頻帶中。在本文中，我們建構一種混合多載波/多載波-直序展頻之分碼多工系統於每一子頻帶中，此系統除了利用時域展頻之外也用了頻域展頻。至於多速率傳輸則使用已知的多碼存取和可變展碼長度存取技術來達成。此外我們提出去相關和干擾消除多戶偵測接收機用以克服高速傳輸使用者所遭受到來自等效用戶的多重存取干擾。而這兩種接收機又分別可用結合時頻域和分離時頻域之方法來實現。從模擬結果得知，當我們在增加時域或頻域展碼時，建議使用多碼存取技術配合結合時頻域去相關接收機。若因考量硬體複雜度而採用分離時頻率接收機，則使用可變展碼長度存取技術將是較佳的方法。

關鍵字

多速率；多載波；超寬頻

並列摘要

Ultra wideband (UWB) transmission is adopted in the specific of 802.15 3a for wireless personal area network (WPAN) and applied to multimedia communications. The requirement of high and multiple data rates motivates us to consider how to plan the feasible transceiver structure on available ultra wide bandwidth. Multiband trans-mission technology, which divides the available bandwidth into several conjunctional subbands and transmits information through one subband at one time, is presented here to simplify the hardware complexity and still offer enough wide subbands for multiple access schemes. The novel hybrid MC/MC-DS CDMA structure, which exploits joint time and frequency domain spreading, is constructed in each subband. In another de-signed consideration of multirate communication, we choose the known multirate ac-cess schemes – multicode access and variable spreading length access. Furthermore, we propose two kinds of multiuser detection receivers, to decorrelate and cancel MAI from the effective users of a high rate user due to multipath channel. Two possible imple-mentations, joint and separate TF-domain, are considered for each kind of proposed re-ceivers. From the simulation, we recommend adopting MCD access scheme using joint TF-domain decorrelating receiver whether increasing spreading code assignment on T-domain or F-domain and using joint TF-domain interference cancellation receiver to avoid arithmetic computations of crosscorrelation matrix of TF-domain spreading codes. Considering the issue of the complexity, which means to use separate TF-domain re-ceiver, we prefer adopting VSL access scheme whether increasing spreading code as-signment on T-domain or F-domain.

並列關鍵字

ultra wideband ； multicarrier ； multirate

參考文獻

[1] S. Roy, J. R. Forester, V. S. Somayazulu and D. G. Leeper, “Ultrawideband Radio Design: The Promise of High-Speed, Short-Range Wireless Connectivity,” Pro-ceedings of the IEEE, vol. 92, pp. 295 – 311, Feb. 2004.

[5] R. A. Scholtz, “Multiple access with time-hopping impulse modulation,” presented at the Conf. Milcom, Bedford, MA, 1993.

[6] , “Impulse radio: How it works,” IEEE Commun. Lett., vol. 2, pp. 36–38, Feb. 1998.

[7] , “On the robustness of ultra-wide bandwidth signals in dense multipath envi-ronments,” IEEE Commun. Lett., vol. 2, pp. 51–53, Feb. 1998.

[9] R. J. M. Cramer, R. A. Scholtz, Z. M. Win, “Evaluation of an ultra-wide-band propagation channel,” IEEE Transactions on Antennas and Propagation, vol. 50, pp. 561-570, May. 2002.

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多速率多頻帶混合多載波/多載波-直序展頻之分碼多工用於超寬頻傳輸

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