Characteristics and performance of various VDSL RFI suppression techniques

The past few years have seen ADSL widely deployed as the telephone companies attempted to grow their market share in the consumer service industry of high speed internet access. Bundling a digital video service offering together with data and phone services is seen by many telephone companies as the next step for protecting, if not growing, their market share. VDSL is one technology that promises to provide the required rates over existing twisted pairs for supporting these services.VDSL employs the frequency band spanning from 25 kHz to 12 MHz, a significantly larger band than used by ADSL. As a consequence, the VDSL band is adjacent to or overlaps with other radio signalling bands such as Amateur Radio (HAM) and AM broadcasts. These signals may introduce radio frequency interference (RFT) in VDSL signals, which will degrade VDSL performance.Many approaches can be found in the literature for reducing the impact of RFI on VDSL communication. These methods however may not always be as practical or efficient as predicted when applied to real systems adhering to a common standard. This thesis attempts to quantify the impact of RFI on typical multi-carrier modulation (MCM) basedVDSL systems, also known as discrete multi-tone (DMT) VDSL, and researches some of the most promising suppression techniques for mitigating the effect of RFI in such systems. Elaborate end-to-end simulations are carried out to investigate the effect of these suppression techniques on system performance, both with and without RFI present. The thesis concludes by highlighting the performance and complexity characteristics of the various RFI suppression techniques considered.