應用於感知無線電系統四個頻道多相位濾波器

近年來，隨著無線通訊技術的發達，人們希望能夠隨時隨地傳送資料交換訊息，所以對於頻寬的需求量愈來愈大。然而目前頻譜使用的方式效率並不高。因此，感知無線電系統概念應之而生。感知無線電系統是一種能偵測外界環境變化，並且動態地改變自己的頻寬、調變、功率以及其它參數的無線電系統。所以，此系統能達到最佳的表現與最大的傳輸率。本論文的感知無線電系統應用在5 GHz的UNII頻帶。希望能與該頻帶原主要使用者－802.11a系統共存，並且不打擾到原主要使用者的運作。此感知無線電系統在運作中需要一個八個頻道多相位濾波器，及即本篇論文的重點。由於初步的試驗與功能的驗證，本論文僅實現中間四個頻道，即四個頻道多相位濾波器。此四個頻道多相位濾波器是由兩個可調式複數濾波器所組成。應用複數濾波器改變中心頻率的技巧與gm-C濾波器改變頻寬的方法。經過適當的組合，就可完成四個頻道多相位濾波器。此濾波器能夠根據系統需求任意選擇不同頻道，並且已在台積電0.18微米製程中實現。

關鍵字

複數濾波器；多相位濾波器；感知無線電

並列摘要

With advance in the technology of wireless communication, people are able to transmit data and exchange information anywhere anytime nowadays. Hence the demand on the bandwidth is increasingly higher. However, at present, the frequency spectrum usage is not very efficient, so cognitive radio systems are proposed to solve the issue. This system has capability to sense the environment variances, and dynamically adjusts its bandwidth, modulation, power, and other parameters, in order to achieve optimal performances and maximum transmission rate. The cognitive radio system presented in this thesis is aimed at 5-GHz UNII band. We expect that the system coexists with the primary user, 802.11a, without interference. The cognitive radio system in operation requires a 8-channel poly-phase filter, which is the subject of this thesis. Due to the functional verification and the nature of trial of the research, this thesis only accomplishes the middle 4 channels, 4-channel poly-phase filter. The 4-channel poly-phase filter consists of two programmable complex filters. The programmable center frequency technique of the complex filter and the programmable bandwidth method of the gm-C filter are applied. The 4-channel poly-phase filter can be completed through appropriate combinations. The filter is able to select different channels according to the demand of the system, and has been fabricated in a TSMC 0.18-μm CMOS technology.

並列關鍵字

complex filter ； poly-phase filter ； cognitive radio system

參考文獻

[1] J. Yang, "Spatial Channel Characterization for Cognitive Radios," MS Thesis, UC Berkeley, 2004.

[2] J.-P. Lien, "Design of a MIMO OFDM Baseband Transceiver for Cognitive Radio Systems," MS Thesis, National Taiwan University, July 2005.

[3] B. Razavi, RF Microelectronics, Prentice Hall, 1998.

[4] B. Nauta, "A CMOS Transconductance-C Filter Technique for Very High Frequencies," IEEE J. of Solid-State Circuits, vol. 27, pp. 142-153, Feb. 1992.

[6] B. Guthrie, J. Hughes, T. Sayers, and A. Spencer, "A CMOS Gyrator Low-IF Filter for Dual-Mode Bluetooth/ZigBee Transceiver," IEEE J. of Solid-State Circuits, vol. 40, pp. 1872-1879, Sept. 2005.

國際替代計量

應用於感知無線電系統四個頻道多相位濾波器

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