Telefonaktiebolaget Lm Ericsson (publ)

Per Ödling

Fredrik Lindqvist

Antoni Fertner

Per Ola Börjesson

Jaume Rius I Riu

Pål Frenger

Thomas Magesacher

Henrik Back

Axel Frank Jensen

Adam Wiå

Stefan Allevad

Per Håkan Albin Johansson

Björn Olof Bohlin

Jonas Gustafsson Rosenberg

Per Hakan Albin Johansson

The present invention relates to a precoder for a communication system arranged to provide transmission blocks for transmission over a transmission channel based on inputted symbol blocks. The precoder is arranged to pre-distort each symbol block based on an estimate of the characteristics of the transmission channel so that the corresponding transmission block appears to be undistorted after transmission over the transmission channel. In accordance therewith, the precoder is arranged to apply Tomlinson-Harashima precoding on a sum of a first measure corresponding to predistortion so as to remove intrasymbol interference and a second measure corresponding to predistortion so as to remove intersymbol interference. The present invention further relates to a method for providing transmission blocks for transmission over a transmission channel in a communication system.

Precoder for a communication system and methods used in said communication system

A method and device for estimating one or more transmission properties of a telecommunication transmission line. At least one signal is sent on the line, the at least one signal including at least two frequencies for which the absolute value of the line propagation constant times the line length is less than &#x3c0;, and a resulting signal is received. An estimate of at least one transmission line property is then determined by examining the relationship between the sent and resulting signal or signals. The process may be repeated, if necessary. The estimate determination may also be repeated one or more times, with each successive estimate preferably using for the determination only those frequencies for which, as previously estimated, the absolute value of the line propagation constant times the line length is less than &#x3c0;.

Method and device for estimating properties of a telecommunication transmission line

A method and arrangement in a communication system for dynamically allocating communication system frequency spectrum after cross-talk interface between transmission medias used for upstream and downstream communication in the frequency spectrum. After detecting cross-talk interface on a disturbed transmission medium caused by transmission on a disturbing transmission medium, the arrangement transmit a media control signal on the disturbed transmission medium and detects a reproduced media control signal that is reproduced due to cross-talk on the disturbing transmission medium. The disturbed or disturbing transmission media can then be dynamically allocated different frequency spectrum to eliminate the interface. In one embodiment, each transmission medium has a default transmission direction, and if one of the transmission is in a direction opposite the default direction, that transmission is reassigned to another transmission medium.

Dynamic allocation of frequency spectrum

The invention refers to single-ended test of a loop with the aid of a transceiver, wherein an input impedance (Z(&#x192;)) of the loop is generated. The transceiver has a digital part, a codec and an analog part and is connected to the loop. With the aid of a transmitted and a reflected broadband signal (v, v) an echo transfer function H(&#x192;)=V(f)/V(f) is generated, which also can be expressed as Here Z(&#x192;), Z(&#x192;) and H(&#x192;) are model values for the transceiver. In a calibration process a test transceiver, with the same type of hardware as the transceiver, is connected to known impedances, replacing the loop. H(&#x192;)=V(f)/V(f) is generated for the known impedances and the model values are generated and are stored in a memory in the transceiver. The stored model values are then used when the input impedance (Z(&#x192;)) for the loop is generated after a measurement of the broadband signal (V, v) is performed.

Method and arrangement for signal loop test

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Älvsjö, Sweden

Per Ödling