Coding technique in discrete multi-tone (DMT) based communications systems

摘要

In an Asymmetric Digital Subscriber Loop (ADSL) Discrete Multi-Tone (DMT) system, ADSL DMT equipment includes an encoder that operates on a DMT input signal representing ƒ symbols/sec. to generate, for transmission, a DMT output signal representing Nƒ symbols/sec., where N>1, and where each symbol from the DMT input signal is generated in a redundant form in the DMT output signal. In one example of a redundant form, each symbol from the DMT input signal is repeated in N consecutive symbol intervals in the DMT output signal. In another example of a redundant form, every N DMT input symbol values are transmitted in 2N consecutive symbol intervals in the DMT output signal. These 2N consecutive symbols in the DMT output signal include 1) N symbols whose values equal the respective N DMT input symbol values and 2) N symbols whose values are a function of the respective N DMT input symbol values.