A 4-Channel Poly-Phase Filter for Cognitive Radio Systems
Date Issued
2006
Date
2006
Author(s)
Chen, Guan-Jun
DOI
en-US
Abstract
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.
Subjects
複數濾波器
多相位濾波器
感知無線電
complex filter
poly-phase filter
cognitive radio system
Type
thesis
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