xDSL DMT modem using sub-channel selection to achieve scaleable data rate based on available signal processing resources

摘要

A high speed modem is provided which uses a selectable, desirable portion of the total available bandwidth of a transmission channel. In a preferred embodiment, the invention is incorporated in a dedicated hardware circuit which is connected on one end to a data processor and on the other end to an upstream transceiver through a channel supporting an Asymmetric Digital Subscriber Loop (ADSL) standard. The achievable target data rate of the modem is based on the capabilities of an analog front end (AFE) used in the modem, and a signal processor within the dedicated hardware. In particular, the modem AFE contains subband filtering which causes an upstream transceiver to use only a selected number of available sub-channels for downstream data transmission. The data rate of the modem is increased by upgrading the AFE or the signal processor in order to increase the number of processable transmitted downstream sub-channels.