Rohde and Schwarz Gmbh & Co. Kg

Abb Technology Ag

Dimitri Korobkov

Rainer Bott

Hans Benninger

Karlheinz Pensel

Patrick Langfeld

Günter Wicker

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 for frequency and time synchronization of a receiver for receiving Orthogonal Frequency Division Multiplexing (OFDM) signals is described. A quality criterion of a OFDM signal is determined during one of the frequency intervals (hops) for each point of one of the two-dimensional frequency and time search areas. The area point having the optimum quality criterion (&#x3c4;, f) of the OFDM signal is then determined on the basis of said quality criterion, and the receiver is synchronized on the nominal frequency in view of the different between the nominal frequency (f) and the frequency value (f) corresponding to the optimum quality criterion. The OFDM signal may be demodulated and decoded starting with the time value (&#x3c4;) corresponding to the optimum quality criterion.

Synchronization of an orthogonal frequency division multiplexing (OFDM) receiver

The invention relates to a system for transmitting data according to the frequency hopping method. The digital data, which is transmitted in suddenly changing transmission frequency hops, is encoded according to a woven code consisting of an interlinked external and internal convolution code. The data to be transmitted by hop is preferably distributed over several parallel hops sent with different frequencies.

Growing community of inventors

Frankfurt-am-Main, Germany

Dimitri Korobkov