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Status Report of Digital Subscriber Line Work in Committee T1. Rick Townsend T1E1 Chairman Wayne Zeuch T1 Vice Chairman. Broadband Access. Spectrum Management. Enhancements to T1.417-2001, Spectrum Management for Loop Transmission Systems”
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Status Report of Digital Subscriber Line Work in Committee T1 Rick Townsend T1E1 Chairman Wayne Zeuch T1 Vice Chairman GSC-8, OTTAWA
Broadband Access Spectrum Management • Enhancements to T1.417-2001, Spectrum Management for Loop Transmission Systems” • Requirements and recommendations for DSL loop systems; addresses deployment guidelines for power spectral density (PSD), total average power, transverse balance, longitudinal output voltage • Issue 2 specifically addresses spectral compatibility of repeaters, intermediate transceivers; also now addresses HDSL and VDSL • Enhancements address NRIC-V directives (the Network Reliability and Interoperability Council is an advisory committeeof the U.S.FCC) • Dynamic Spectrum Management (DSM) • Improving reliability and increasing data rates through measurement and/or dynamic management of DSL spectral density • May provide recommendations for adaptive or dynamic assignment of lines, signals, spectra • Possible new directions include programmable PSDs and multi-channel crosstalk modeling to achieve spectrum optimization GSC-8, OTTAWA
Broadband Access ADSL (Asymmetric DSL) • Bonding approaches to increase bit-rates for symmetric services (> 733.3 kBaud) • eSHDSL: Studying power spectral density compatibility for operating with ADSL and VDSL • Potential for multi-Mbit/s rates (2 pair) and 10 Mbit/s (3 pair) • Discussions on extending ADSL bit rates for asymmetric service (ADSLplus or ADSL2+) • Spectral compatibility of 256 kHz upstream channel relative to ITU-T Rec. G.992.5 SHDSL (Single-pair High-speed DSL) GSC-8, OTTAWA
Broadband Access M²DSL (Multi-rate Multi-pair DSL) • Formerly known as 10 MDSL; supporting bit rates up to 10Mbit/s on short loops • Bonding techniques (applied to multiple wire pairs for higher aggregate bit-rates) • Guidelines for enabling multi-Mbit rates to all customers on loops to meet rate-reach objectives • Addressing symmetric bit-rate transmission; may also address asymmetric transmission • Consideration of advanced performance optimization techniques for multi-pair transmission • Multi-pair vectoring, advanced coding GSC-8, OTTAWA
Broadband Access VDSL (Very-high-bit-rate DSL) • VDSL American National Standard for Trial Use, T1.424 (expires March 2004) • Functional requirements and common specification, SCM, and MCM • Liaison with IEEE 802.3ah (Ethernet in the First Mile – EFM) to identify an appropriate solution for the metallic, copper-based Physical Layer • Progress on defining: • bit-rate reach tests, power spectrum density tests, and up-stream power back-off tests • Further work needed in defining: • Impulse noise, latency, stability testing GSC-8, OTTAWA
Broadband Access Network End Line Sharing Splitter Standard • Describes electrical characteristics of 4 line sharing splitters that may be used to deploy DSL technologies over metallic lines also used to provide voice-band service • Protection for DSL signals from PSTN high frequency transients and impedance effects (ringing, ring-tip, off-hook) • T1 standard completed and currently out for ballot • Type A splitter (based on T1.413-Annex E); Type B considers envelope delay and DSL band attenuation; Type C addresses VDSL and 998 spectrum plan; Type D addresses ISDN BRI service. In-Line Filter Standard • Describes electrical and physical characteristics of an in-line filter to protect voice-band premises equipment from the high frequencies of digital data over voice (25 kHz to 12 MHz range) • Revision of T1.421-2001 adds inter-modulation distortion and transverse balance testing GSC-8, OTTAWA
Broadband Access References • T1.413-1998, T1.413a-2001,Network and Customer Installation Interfaces Asymmetric Digital Subscriber Line (ADSL) Metallic Interface(Revision in ballot) • T1.417-2001, Spectrum Management for Loop Transmission Systems(Revision in ballot) • T1.418-2002, High bit rate Digital Subscriber Line - 2nd Generation (HDSL2/HDSL4) Issue 2(Revision of T1.418-2000) • T1.421-2001,Network to Customer Installation Interfaces - Asymmetric Digital Subscriber Line (ADSL) Metallic Interface(Revision in progress) • T1.424-Trial Use, Interface Between Networks and Customer Installations - Very-high Speed Digital Subscriber Lines (VDSL) Metallic Interface (Trial-Use Standard) GSC-8, OTTAWA