Discrete multitone modulation with principal component filter banks

Discrete multitone (DMT) modulation is an attractive method for communication over a nonflat channel with possibly colored noise. The uniform discrete Fourier transform (DFT) filter bank and cosine modulated filter bank have in the past been used in this system because of low complexity. We show in this paper that principal component filter banks (PCFB) which are known to be optimal for data compression and denoising applications, are also optimal for a number of criteria in DMT modulation communication. For example, the PCFB of the effective channel noise power spectrum (noise psd weighted by the inverse of the channel gain) is optimal for DMT modulation in the sense of maximizing bit rate for fixed power and error probabilities. We also establish an optimality property of the PCFB when scalar prefilters and postfilters are used around the channel. The difference between the PCFB and a traditional filter bank such as the brickwall filter bank or DFT filter bank is significant for effective power spectra which depart considerably from monotonicity. The twisted pair channel with its bridged taps, next and fext noises, and AM interference, therefore appears to be a good candidate for the application of a PCFB. This is demonstrated with the help of numerical results for the case of the ADSL channel

Statistical Analysis of VoDSL Technology for the Efficiency of Listening Quality of 640k/640k

Next-generation Internet technology will offer high performance and high capacity traffic aggregation and scalability. Voice over Digital Subscriber Line (VoDSL) technology allows service providers to offer multiple telephone lines over a single subscriber line in addition to high speed data transmission services. This article provides a baseline test for the Listening Quality (LQ) using VoDSL access technology by using Voice/Listening Quality (V/LQ) transmission with voice compression while countinously downloading files. The result will be to enable the efficiency of the LQ and its statistical analysis based on a Digital Subscriber Line (DSL) service at level 640K/640K for each American National Standards Institute (ANSI) and Carrier Serving Area (CSA) loops

Zipper - a Duplex Method for VDSL based on DMT

We present a new duplex scheme, called Zipper, for discrete multitone (DMT)-based very high bit-rate digital subscriber line (VDSL) systems on copper wires. This scheme divides the available bandwidth by assigning different subcarriers for the upstream and downstream directions. It has high flexibility to divide the capacity between the up and downstream, as well as good coexistence possibilities with other systems such as ADSL. Simulation results show the high bit-rate performance in different environments such as mixed ADSL and VDSL traffic under radio frequency interference and with different background noise source

Measurement And Modeling Of Short Copper Cables For Ultra-wideband Communication

High-speed communication using the copper network, originally installed for telephony, is one of the dominant Internet access techniques. Several variants of a technology referred to as digital subscriber line (DSL) have been developed, standardized and installed during the last two decades. Essentially, DSL achieves high rates by exploiting wide bands of the copper cable channel. The shorter the cable, the wider the band that can be used efficiently for communication. Current DSL standards foresee the use of bands up to 30MHz. Cable properties have been studied by means of measurements, characterization and modeling up to frequencies of 30MHz. Recent investigations have shown that it is feasible both from technical and from economical point of view to exploit very short cables (up to 200m) even further and use bands above 30MHz. A prerequisite for further evaluation and the design of such ultra-wideband copper (UWBC) systems is the extension of existing cable models to higher frequencies. This paper presents wideband measurement results of insertion loss and crosstalk coupling in a 10-pair cable of various length values for frequencies up to 200MHz. We compare the results with extrapolations of cable models that are established in the 30MHz-range.6390Chen, W.Y., (1998) DSL: Simulation Techniques and Standards Development for Digital Subscriber Line Systems, , Macmillan Technical Publishing, ISBN 1-57870-017-5G.selt: Updated issues list for G.selt (2004) ITU-T Temporary Document SS U09, , ITU-TAsymmetric digital subscriber line (ADSL) transceivers (1999) ITU Recommendation G.992.1, , ITU-T, JuneAsymmetric digital subscriber line (ADSL) transceivers (1999) ITU Recommendation G.992.2, , ITU-T, JuneAsymmetric digital subscriber line (ADSL) extended bandwidth (ADSL2+) (2005) ITU Recommendation G.992.5, , ITU-TStarr, T., Cioffi, J.M., Silverman, P., (1998) Understanding Digital Subscriber Line Technology, , Prentice Hall, Englewood CliffsDedieu, H., The copper channel - Loop charactersitics and models (2005) Fundamentals of DSL Technology, , ch. 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