Broadcast Digital Subscriber Line

This Recommendation describes Asymmetric Digital Subscriber Line (ADSL) Transceivers on a metallic twisted pair that allows high-speed data transmission between the network operator end (ATU-C) and the customer end (ATU-R). It defines a variety of frame bearers in conjunction with one of two other services or without underlying service, dependent on the environment: 1) ADSL transmission simultaneously on the same pair with voice band service; 2) ADSL transmission simultaneously on the same pair with ISDN (Appendix I or II/G.961

Characterization of the existing telephone subscriber loops infrastructure used by the modern broadband telecommmunication services such as xDSL has been presented in the paper. As loop transmission medium quality is one of key requirements for performance capabilities of these services, a method for modelling and simulation of subscriber loops infrastructure in the frequency domain is described. This method is based on ABCD transmission parameters matrix and the appropriate twisted pair cable model representation to account for frequency dependence of its primary per-unit length parameters. It is used to obtain some important subscriber loop characteristics over the service operating frequency band and to analyse quality of cable transmission from the aspect of Heaviside criterion fulfillment.

In this paper, design, simulation and implementation of Asymmetric Digital Subscriber Line (ADSL) modem is presented which can be applied to different telephone networks. The ADSL modem is modeled and simulated under the MATLAB version 7.3 (R2006b) environments by which the simulation is achieved for both the downstream and upstream directions of the modem. The ADSL modem with a transmission throughput between 640 kbps and 6 Mbps operating over most of existing telephone subscriber loops has been implemented on TI TMS320C6713 DSP for consumer multimedia applications. Except the Analog Front End, all the basic building blocks of the ADSL modem functionalities are implemented with DSP platform. We use Real-Time Data Exchange (RTDX) as a way to debug and test our DSP designs.

IEEE Journal on Selected Areas in Communications, 1995

The fundamental limits of the outside loop pIant to carry high-speed digital (bi-directional HDSL and ADSL) data are reported. The paper focuses on the copper wire pairs, drop lengths, and interconnects that convey data over the 'last mile" to almost all businesses and residences in the US. The two major customers, businesses and households, are class%&, characterized, and categorized by the distance to the central oEce or the remote terminal. Their spectral capabilities are computed and their ultimate digital capabilities are reported. The crosstalk limitations inherent in the plant are also computed and verified against the loss of signal due the distance and spectral constraints. The signal to noise ratio can thus be estimated to ascertah the transmission quality through the plant. Accordingly, the paper reports on losses, bandwidths, and bit rates in the first half, and discusses the major bottlenecks in the second half.

Proceedings. Electrotechnical Conference Integrating Research, Industry and Education in Energy and Communication Engineering', 1989

The analysis of near end crosstalk in digital transmission over subscriber loop is presented. An analytical expression for NEXT between parallel and between twisted lines is evaluated. -

IEEE Transactions on Communications, 2000

Absrracr-In this paper we investigate the bit error rate (BER) performance of a passband single-carrier QAM transceiver for Asymmetric Digital Subscriber Lines (ADSL), with additive white Gaussian noise (AWGN) and sell far-end crosstalk (FEXT) as the main disturbances. The major difference with previous contributions on ADSL performance Is that we present a simple approximate analytical expression for the signal-to-noise ratio (SNK) margin, which clearly shows the effect of various cable and system parameters (such as loop length, transmit power, QAM constellation size, bit rate, ...) on ADSL performance. From this expression, we determine the optimum constellation size and the maximum achievable bit rate as a function of the loop length.

International Journal of Digital & Analog Communication Systems, 1992

This paper analyses different equalization, coding and signal constellation alternatives for the proposed high‐bit‐rate (800 kb/s) digital subscriber loop transmission interface. The simulation results presented in the paper demonstrate that bit rates above 1000 kb/s at acceptably low bit‐error rates (≤ 10−7) are feasible, if baseband transceivers with appropriate equalization and simple trellis coding are used. It is also shown that baseband transmission and Tomlinson precoding provide a significant performance advantage over bandpass transmission and decision‐feedback equalization, respectively.

IEEE Communications Magazine, 2002

The objective of this article is to present a promising voice over digital subscriber line (VoDSL) solution: an alternative method that uses physical layer transportation to provide channelized VoDSL (CVoDSL). This article also presents the advantages that the CVoDSL provides to the customers in terms of high-quality services and lower cost, and service providers in terms of market growth and success. It also offers a set of requirements, architectural design, and implementation scenarios that provide end-to-end solutions for CVoDSL.

Proceedings of the IEEE, 1997

The provision of broad-band services based on either the Internet or the asynchronous transfer mode (ATM) technique requires a new generation of access networks. In the short term, solutions such as x-digital subscriber line (DSL) and hybrid fiber coaxial (HFC), allowing the reuse of existing infrastructures, look very promising. For the longer term, new infrastructures based either on radio or on optical access links seem preferable. Three x-DSL techniques aiming at high-bit-rate transmission over twisted pairs are presented: high-bit-rate DSL, asymmetrical DSL, and very-high-bit-rate DSL. An extension of existing cable television networks known as HFC is also described. Two other prospective approaches, wireless in the loop (WITL) and fiber in the loop (FITL), are then presented. Several techniques are considered for WITL: digital enhanced cordless telecommunication, local multipoint distribution service, wireless ATM, and low earth orbit satellite constellations. The various architectural alternatives for the FITL approach are discussed, a special interest being dedicated to the synchronous digital hierarchy self-healing loop and the ATM over passive optical network. In our presentation, we mention the main experiments and the standardization activities inherent to the domain.

A popular approach to designing high-speed modems for use on voice-grade telephone channels is to use a high order modulation scheme combined with a digital architecture. This paper describes the development of a modem structure which uses the DSP56001 signal processor to implement 49 quadrature partial response signalling (49 QPRS). The choice of 49 QPRS is justified by its high spectral efficiency and reasonable error rate performance. This system is being developed for two applications, which are described in the paper.