Alternative configurations for an adsl system operating in a time duplex noise environment

Abstract

An ADSL system for operating in a time duplex system that provides alternative configurations for limiting crosstalk in a broadband network is disclosed. The ADSL system introduces a trial bitmap profile configuration to maximize the bit rate at which information is transmitted, regardless of network topology. In a simplified embodiment, a composite signal to noise ratio is derived from a minimum far end crosstalk signal to noise ratio and a minimum near end crosstalk signal to noise ratio. A maximum bit rate for the transfer of information, which is directly related to the derived composite SNR, is then determined. Information is then transmitted simultaneously between an asymmetric digital subscriber line central office and an asymmetric digital subscriber line customer premise at the determined maximum bit rate. In an alternative embodiment, a selection is made between a single, dual, or trial bitmap profile configuration as a function of noise environment and channel loop length, thereby ensuring maximum bit rate throughput of an ADSL system operating in the presence of TCM-ISDN interference.