Abb Technology Ag

Patrick Langfeld

Hans Benninger

Dimitri Korobkov

Stefan Ramseier

Dmitri Korobkov

Vladimir Potapov

Hans Joerg Maag

Data transmission is disclosed over a transmission channel that is subject to narrowband interferers. An increased overall bit or data transmission rate is achieved by an exemplary method of determining a channel capacity of plural sub-channels of the transmission channel based on a net background noise power estimation. The net background noise power contains only white noise-like contributions and excludes, to a reasonable extent, noise contributions or signal power from narrowband interferers. Hence, the net background noise power can be reduced. For example, an Orthogonal Frequency Division Multiplex (OFDM) signal code construction or bit allocation scheme can be chosen that provides for optimized data transmission at a data rate that approximates or approaches the more realistic channel capacity of an individual sub-channel, resulting in an increased overall bit or data transmission rate.

Method of determining a channel quality and modem

A method and modem are provided for obtaining an optimized efficiency of an Orthogonal Frequency Division Multiplex (OFDM) data transmission, such as for power line communication, for example. The length or duration of a guard interval or cyclic prefix in an OFDM symbol is newly selected at each start-up of a modem while initializing or preparing the OFDM data transmission. The length of the guard interval can be given by the number of samples in a time-discrete representation, and the value of such number of samples that is retained for the subsequent data transmission can be selected from a plurality of pre-determined possibilities based on an evaluation of a channel quality of a communication channel including a physical line to which the modem is connected. Hence, the selected value depends on actual transmission conditions, and the optimization potential offered by a more flexible handling of system parameters is exploited to meet changing conditions on the physical line.

Initialization of and modem for an OFDM data transmission

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Karlsruhe, Germany

Patrick Langfeld