離散小波多音調為基礎之感知無線電基頻收發機之設計與實作

Design and Implementation of a Cognitive Radio Baseband Transceiver using Discrete Wavelet Multi-Tone Modulation

陳冠宏(Kuan-Hung Chen)

指導教授 ： 闕志達

國立臺灣大學/電機資訊學院/電機工程學研究所/博士(2006年)

https://doi.org/10.6342/NTU.2006.02345

摘要

本篇論文提出一個新的感知無線電系統架構，目標是透過對使用者目前所在之處，未被使用到的全球移動通訊系統（GSM）之頻譜進行再利用，來提供類似802.11 WLAN的無線區域網路之服務。我們將過去針對所謂的數位用戶迴路（DSL）系統所提出的離散小波多音調（discrete wavelet multi-tone）調變，用於感知無線電系統。相較於熱門的正交多頻分工（OFDM）調變，該調變可提供較高的旁葉衰減（sidelobe attenuation），故其產生的鄰近頻道洩漏（adjacent channel leakage）功率較低，且具備較佳的抗干擾能力。當感知無線電系統的可用頻帶是由零碎而不連續的小塊頻帶所構成，且其可用頻譜組態可能隨時間或地域而變化的情形下，離散小波多音調調變的特性使其優於正交多頻分工調變。

為了進行收發機設計，我們首先針對離散小波多音調調變推導其訊號模型，並分析其訊號與干擾的特性，就同步、通道估測、等化等工作的需求，決定合適的演算法。設計完成之後，我們採用0.18-

關鍵字

感知無線電 ； 離散小波多音調 ； 全球移動通訊系統 ； 無線區域網路 ； 基頻接收機

並列摘要

In this thesis, design and implementation of a discrete wavelet multi-tone (DWMT) based baseband transceiver for cognitive radio applications are presented. The proposed system aims to provide wireless local-area network (WLAN service similar to IEEE 802.11 WLAN by exploiting the unused GSM spectrum. The DWMT modulation scheme originally proposed for wireline digital subscriber loop (DSL) applications is adopted as the modulation scheme. This modulation has stronger side-lobes attenuation than the popular OFDM modulation and thus generates much lower adjacent channel leakage, making it suitable for applications with dynamically-allocated spectrum. Signal and interference analysis of the adopted DWMT modulation is presented and signal processing techniques that tackle synchronization, equalization, and detection are developed.

The entire DWMT-based baseband receiver is integrated and implemented in 0.18μm CMOS technology. Techniques such as hardware sharing, common term extraction, subcarrier constant multiplications removal, etc., are applied for hardware reduction. In addition, novel bi-directional SRAM-based delaylines are designed for memory saving. Measurement results of the fabricated receiver IC show that it functions well at 25.6 MHz operating frequency while drawing 165 mW from a 1.8 V supply voltage. When the whole 25.6 MHz bandwidth is available, this receiver IC can provide up to 153.6 Mbps of data transmission.

並列關鍵字

cognitive radio ； discrete wavelet multi-tone ； wireless local-area network ； GSM ； baseband receiver

參考文獻

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