| Summary: | 碩士 === 國立交通大學 === 電子工程系所 === 93 === VDSL is a promising technology of unshielded twisted pairs in the public telephone network for the purpose of broadband access. A problem with this technology is that the frequency range used for VDSL signaling is shared with amateur radios and broadcast AM radios. A transmitter in the proximity of a wire will induce an electrical signal in the wire; this is called Radio Frequency Interference (RFI).
In general, amateur radio (HAM) is more harmful than AM in VDSL. In this paper, we will focus on dealing with amateur radio. In regard to RFI model, the simplest model is zero-order with a constant RFI envelope in one Zipper VDSL symbol period [9]. But in ETSI VDSL systems, the symbol periods are several times longer than that of Zipper VDSL. The RFI envelop in one symbol may not be constant. Therefore, the use of such a model in digital RFI cancellation is not fully justified. We started with a more accurate RFI model and developed an improved way for RFI cancellation. Simulation results show support to our assumptions and the effectiveness of our algorithm.
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