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.

Digitally-tunable echo-cancelling analog front end for wireline communications devices

Abstract: The present invention, generally speaking, provides a digitally-tunable, echo-cancelling analog front end (AFE) for wireline digital communications. The analog front end is especially useful in a High-bit-rate Digital Subscriber Line (HDSL) or HDSL2 environment. An analog echo simulation path is provided capable of simulating echo from a wide variety of echo paths. Digitally controlled attenuators are provided in the transmission path and in the analog echo simulation path. Also provided is a digital-tunable equalizer stage. The equalizer stage is tuned to match the characteristics of the receive path. The same arrangement may be adapted for various DSL technologies, i.e., xDSL. There results an analog front end that is well-adapted to high-speed wireline communications.

System and method of providing a bi-directional DSL connection

Abstract: A system for providing a bi-directional digital subscriber line connection to a network includes a digital subscriber line access multiplexer with a pool of digital subscriber line modems, and switching logic connecting customer premises to the modem pool. The switching logic has more inputs than outputs, and is configured to share access to the modem pool among the inputs on a per-session basis. A session has a dedicated modem connection to the network to provide a limited number of simultaneous dedicated digital subscriber line bi-directional connections to the network.

Market Coverage and Service Quality in Digital Subscriber Lines Infrastructure Planning

Abstract: Digital subscriber lines (xDSL) belong to a family of technologies that provide the ability to transmit digital data over local telephone (copper) infrastructure. As the second most popular broadband platform in the United States, it is estimated that over twenty-five million xDSL lines are in service, capturing nearly 30 percent of the U.S. broadband market. While the service range of xDSL is somewhat limited, often extending to a maximum of 18,000 feet from a central office (CO), available bandwidth also decays as distance increases from the CO. As a result, there are often marked disparities in the quality of xDSL service within market areas. This article proposes a bi-objective location model for maximizing both service coverage and quality of coverage in siting digital subscriber line access multiplexers (DSLAMs). An application of the developed model highlights important implications for telecommunication policy.

A novel reduced-complexity MAP equalizer using soft-statistics for decision-feedback ISI cancellation

Abstract: A novel version of the reduced-state Bayesian maximum a posteriori probability/decision-feedback (MAP/DF) equalizer for ISI channels with long impulse responses is presented. The main feature of the proposed equalizer is that the soft-statistics generated by the MAP receiver are employed to recursively compute a suitable index of the actual reliability of the (soft) decisions feeding the DF filter. Therefore, in the presented equalizer the usual (over-optimistic) assumption of error-free decisions at the input of the feedback filter is relaxed and numerical results supporting the actual effectiveness of the proposed MAP/DF equalizer are provided for the so-called high-bit-rate digital subscriber line (HDSL) test-loop # 4.

Digital RFI suppression in DMT-based VDSL systems

Abstract: In this paper we describe a method for supressing Radio Frequency Interference (RFI) in Discrete Multitone (DMT) based Very High bit rate Digital Subscriber Line systems. The method operates in the frequency domain of a DMT-system. It is based on a Taylor-expanded transfer function which maps the disturbance from the RF-signal onto the DMT-carriers. By measuring the RF-disturbance on a few unmodulated DMT-carriers we are able to subtract estimates of the disturbance from every modulated DMT-carrier. The RF-signal is assumed to be an unknown narrowband signal. Simulation results show that this method, applied to an RFI-signal with the same average power as the VDSL-signal, reduces the SNR-loss from about 20 dB to less than 1 dB.