GSC /09/2015GSC-8, OTTAWA Rick Townsend T1E1 Chairman Wayne Zeuch T1 Vice Chairman Status Report of Digital Subscriber Line Work in Committee T1

23 September 2015GSC-8, OTTAWASlide 2 Broadband Access Enhancements to T , 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 committee of 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 Spectrum Management

23 September 2015GSC-8, OTTAWASlide 3 Broadband Access Bonding approaches to increase bit-rates for symmetric services (> 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) ADSL (Asymmetric DSL) SHDSL (Single-pair High-speed DSL) 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

23 September 2015GSC-8, OTTAWASlide 4 Broadband Access 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 M²DSL (Multi-rate Multi-pair DSL)

23 September 2015GSC-8, OTTAWASlide 5 Broadband Access 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 VDSL (Very-high-bit-rate DSL)

23 September 2015GSC-8, OTTAWASlide 6 Broadband Access 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 Network End Line Sharing Splitter 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 T adds inter-modulation distortion and transverse balance testing

23 September 2015GSC-8, OTTAWASlide 7 Broadband Access T , T1.413a-2001, Network and Customer Installation Interfaces Asymmetric Digital Subscriber Line (ADSL) Metallic Interface (Revision in ballot) T , Spectrum Management for Loop Transmission Systems (Revision in ballot) T , High bit rate Digital Subscriber Line - 2nd Generation (HDSL2/HDSL4) Issue 2 (Revision of T ) T , 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) References