Simulation and experimental studies of a rate-adaptive digital subscriber loop (RA-DSL) transmission method

Selected results are presented from a simulation study aimed at improving the use of the subscriber loop plant for digital transmission through adaptive bit rate transceivers for ISDN applications. The results show that even with transceiver structures as used for basic rate access, operating in the presence of residual echoes, near-end crosstalk, and white noise, it is possible to achieve bit rates up to 1.5 Mb/s over loops up to 1 km long, and that with bit rates reduced to 50 kb/s a reach of 7.5 km is easily achievable. The principle of operation and circuit design of an experimental rate-adaptive hardware implementation are also described.<>