Performance Evaluation of a Multichannel Transceiver System for ADSL and VHDSL Services

We study the pe r fo rmance of a mult ichannel modulation method f o r two contempla ted subsc r ibe r line d a t a services known a s asymmetr ic digital subsc r ibe r lines (ADSL) a n d very high-speed digital subsc r ibe r lines (VHDSL). I n the ADSL case, we find t h a t over all un loaded Nor th Amer ican subscr iber lines in o u r test se t , a n unidirect ional 1.536 M b / s d a t a r a t e service f r o m the end office t o t h e cus tomer premises is possible on a single twisted pa i r a t a n e r r o r r a t e of lo-’ with a t least a 6 d B marg in using coded mult ichannel modula t ion with sufficient t r ansmi t power. Fu r the rmore , we find t h a t t he proposed ADSL service can co-exist with basic-rate access’ ISDN (or voiceband analog services) on t h e s a m e twisted pa i r with o u r proposed system. I n the VHDSL case, d a t a ra tes in excess of 100 M b / s can be t r ansmi t t ed rel iably, a t a n e r r o r r a t e of lo-’, using uncoded mult ichannel modula t ion on a single twisted pa i r over a relatively sho r t dis tance (5 150 feet) with a sufficiently high sampling r a t e ( ~ 2 4 MHz) a n d t r ansmi t power. I n this s tudy, t he dominan t line impa i rmen t s in the ADSL environment include intersymbol interference (ISI), far-end crosstalk (FEXT) f r o m o the r ADSL services, spill-over near-end crossta lk (NEXT) f r o m baseband services if! the s a m e wire bundle , spill-over f a r end baseband signal on the s a m e twisted pa i r due t o imperfect filtering, a n d addi t ive white Gauss ian noise (AWGN) f r o m such sources as electronic a n d the rma l noises. In the VHDSL environment , ISI, F E X T a n d NEXT f r o m o the r VHDSL services in the s a m e wire bundle , as well a s AWGN, a r e included. Finally, we show t h a t a cost-effective mult ichannel t ransceiver design tha t has been suggested f o r high-speed digital subscr iber lines (HDSL) service will a lso work well for the proposed ADSL a n d VHDSL services with only minimal