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AssigneeLucent Technologies Inc.
InventorsMai-Huong Nguyen, Jean-Jacques Werner
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A communications system employs frequency division duplexing to accommodate symmetric and asymmetric services, while substantially eliminating near-end cross talk. Upstream and downstream channels are separated by a guard band in order to insure that near-end cross talk is kept to a minimum. An asymmetric upstream channel is preferably located at a lower frequency range than that of the asymmetric downstream channel. The guard band between these asymmetric upstream and downstream channels shifts in frequency along with the shift in frequency of the respective upstream and downstream channels as a function of reach. This guard band shifting permits the communications systems to utilize a greater percentage of the frequencies available to it and to thereby substantially maximize the communications rate that it can support. Although the asymmetric guard band is allowed to shift in the manner described, it is not allowed to do so in a manner that would create a conflict with symmetric channels. Additionally, for symmetric services upstream channels are provided both above and below a downstream channel and are located so as not to interfere with asymmetric channels.
A frequency division duplexing telecommunications system which provides very high speed digital subscriber line symmetric and asymmetric services to a plurality of subscribers connected to said system by local subscriber loops comprising varying lengths of two wire pairs thereby defining local subscriber loops of varying reach, said system comprising:
A frequency division duplexing telecommunications system which provides very high speed digital subscriber line symmetric and asymmetric services, comprising:
A method of providing very high speed digital subscriber line duplex telecommunications services, comprising the steps of:
Dependencies are inferred from the claim text.