The present invention provides an iterative method of allocating bandwidth in a twisted pair modem communication network in order to maximize communications speed while reducing NEXT interference. The method determines frequency bandwidths that cause NEXT interference and eliminates these harmful frequencies. In further embodiments, the invention adjusts other parameters of transmission such as decreasing bitloading rates and power within problematic frequency bandwidths, while increasing power and bitloading in the remaining frequencies. The methods provide an iterative process that ensures an appropriate signal to noise ratio and maximum data transfer.

Iterative waterfiling with explicit bandwidth constraints

For ADSL+ deployment between a remote cabinet and customer premises, the upper part of the traditional ADSL downstream frequency band is used whereas the lower part of this trasitional ADSL downstream frequency band is switched off through spectral masking. This way, ADSL+ deployment from the remote cabinet is spectral compatible with ADSL deployment from the central office for a certain service capability wherein the upper part of the traditional ADSL downstream frequency band is switched off.

Spectral compatible remote asymmetric digital subscriber line plus (ADSL+) deployment

A method and system for dynamically inverting an Asymmetric Digital Subscriber Line (ADSL) system. The ADSL system includes a central exchange equipment (CE) connected to a service provider network and a user equipment (UE) connected to a user workstation. The CE and UE are interconnected by a PSTN link. The CE includes an input line for transmitting high-speed data from the service provider network to the user workstation and an output line for receiving medium-speed data from the user workstation. The CE further employs CE coding/decoding means for coding the high-speed data and decoding the medium-speed data. The UE includes an input line for transmitting medium-speed data from the user workstation to the service provider network and an output line for receiving high-speed data from the service provider network. The UE further includes UE coding/decoding means for coding the medium-speed data and decoding the high-speed data. In accordance with the method of the present invention, an inverting request message is transmitted from the UE to the CE. In response to the inverting request message, the CE coding/decoding means are activated for coding medium-speed data on the CE input line and decoding high-speed data on the CE output line. Next, a first acknowledgment message is transmitted from the CE to the UE informing the UE that transmission in reverse mode is authorized. In response to the first acknowledgment message, the UE coding/decoding means are activated. Finally, a second acknowledgment message is transmitted from the UE to the CE informing the CE that switching into reverse mode is completed.

Method and system for dynamically inverting an asymmetric digital subscriber line (ADSL) System

An improved ADSL system with improved data rate is disclosed. In one embodiment, the upstream data bit rate is increased by extending the up stream transmission band. In another embodiment, the downstream data is also increased by extending the downstream transmission band.

Adsl system with improved data rate

Provided is a device for use with a headend, a household and an amplifier. The headend is able to provide signals within a high-frequency band f H . The household is able to provide signals within a low-frequency band f L , and to provide signals within a super-high-frequency band f R , where f L <f H <f R . The device includes a splitter, a diplexer and a combiner. The splitter is arranged to receive the signals within the high-frequency band f H and to split the signals within the high-frequency band f H into a first signal portion within the high-frequency band f H and a second signal portion within the high-frequency band f H . The diplexer is operable to pass the second signal portion within the high-frequency band f H to the household, to pass the signals within the low-frequency band f L to the splitter and to pass the signals within the super-high-frequency band f R . The combiner is operable to provide, to the amplifier, the first signal portion within the high-frequency band f H and the signals within the super-high-frequency band f R .

Return feed forward

A method for providing Digital Subscriber Line (DSL) service to a group of subscribers over respective subscriber loops in the presence of another, existing digital network service provided on at least some of the subscriber loops. Lower, middle and upper frequency bands are assigned for transmission over the subscriber loops, such that the existing digital network service is provided on the lower band. DSL signals are transmitted downstream on the upper band and are received upstream on the middle band, generally without transmitting or receiving DSL signals on the lower band, over those subscriber loops on which the existing digital network service, is provided. Over those subscriber loops on which the existing digital network service is not provided, the DSL signals are transmitted downstream on the lower and upper bands and are received upstream on the lower and middle bands.

Liron Frenkel

Papers

ADSL transmission in the presence of low-frequency network services