High-bit-rate digital subscriber line

About: High-bit-rate digital subscriber line is a research topic. Over the lifetime, 516 publications have been published within this topic receiving 8537 citations. The topic is also known as: HDSL & high-bit-rate DSL.

Method for local exchange subscriber line conferencing

Abstract: A local conferencing exchange subscriber line conferencing system and method using a series of input signals from the phone of a subscriber, such as a dual-tone multifrequency (DTMF) sequence of key inputs starting with a star key input, to initiate the conference. The conference is set up in a bridge and the phone of the subscriber is connected to the bridge. All subsequent callers to the subscriber's phone number at the local exchange carrier are routed and connected to the conference at the bridge. When the conference call ends, the subscriber's phone is returned to normal service.

Spectral compatibility of asymmetrical digital subscriber lines (ADSL) with basic rate DSLs, HDSLs, and T1 lines

Abstract: The results of an analysis of the spectral compatibility of asymmetrical digital subscriber lines (ADSLs) with other digital transport technologies that might coexist in the same binder group are presented. The near-end crosstalk and far-end crosstalk effects of digital subscriber line (DSL)-based transport schemes, such as basic-rate and high-bit-rate DSL (HDSL) and T1 lines, are investigated. Two categories of loop environment design rules are considered. The ADSL transceiver is assumed to be based on either a 16- or 64-point quadrature amplitude modulation (QAM) symbol constellation for a data rate of 1.6 Mb/s. The guardband of the transmit spectrum is assumed to fall within the range of 20 to 110 kHz. The receiver is assumed to be an ideal decision feedback equalizer with a quarter-baud spaced fractionally spaced feedforward equalizer. It is concluded that a 16-point QAM ADSL system, with the carrier frequency at 250 kHz, is a potentially viable transport scheme. >

Crosstalk cancellation in ADSL systems

Abstract: Near-end crosstalk (NEXT) is one of the major impairments to current ADSL downstream transmission. This paper presents two methods for an ADSL receiver to cancel one (dominant) NEXT signal from other types of services (such as HDSL, SDSL, T1 etc). The methods exploit the fact that the crosstalk signal has a large excess bandwidth and its spectra in the main lobe and in the excess band are strongly correlated. The principal idea is then to estimate the crosstalk in some frequency bands (e.g., excess band) and cancel it in other frequency bands (e.g., main lobe). Simulation results show that one of the proposed methods, MMSE estimation and cancellation, is very effective to cancel one (dominant) NEXT and the improvement is significant in terms of the data rate and the line reach for the ADSL service. For example, using a real measured NEXT transfer function, the proposed method can increase the ADSL downstream data rate by 200% for some loops.

System and method for subscriber line service control

Abstract: A signal band width limiter is provided in a telecommunication path that includes a leased unbundled subscriber line. The limiter may be a low pass frequency filter having a band pass range set to the frequencies corresponding to subscribed services. If only POTS service is offered, the filter has a passband range for passing only telephone service signals in a POTS analog frequency range. For ISDN service, the filter has a passband range for passing only telephone service signals within a frequency range prescribed for ISDN. For higher speed data services, such as HDSL and ADSL, filters with appropriate pass bands, up to complete pass through, are provided in the subscriber communication path. As the subscribed service is changed, replacement by the appropriate passband filter readily can be made.

System and method for reducing noise induced by digital subscriber line (dsl) systems into services that are concurrently deployed on a communication line

Abstract: Systems and methods are presented for reducing noise induced by digital subscriber line (DSL) systems into services that are concurrently deployed on a communication line. In the disclosed technique, a power level of a discrete multi-tone (DMT) sub-carrier is adaptively calculated from a signal that is received from a communication line. The signal has information indicative of line conditions, which are further indicative of services deployed on the communication line.