Deutsche Forschungsanstalt Fur Luft-und Raumfahrt E.v.

Thomson Licensing S.a.

Deutsche Thomson-brandt Gmbh

Khaled Fazel

Otto Klank

Patrick Robertson

Michael Ruf

Stefan Kaiser

In the radio transmission method according to the invention, which operates with a mixed frequency and time division multiplex method FDMA/TDMA, in which a relatively broad frequency band is divided according to the FDMA method into a plurality of carrier frequency ranges, namely the so-called main channels, and a plurality of time slots, namely the so-called sub-channels, distributed in a frame structure, are formed on each carrier frequency level according to the TDMA method, a grouping, that is to say a so-called cluster, of subscriber stations is assigned a limited number of main channels. A main channel signal is divided into one or more sub-channel signals which are associated with a cluster and which are transmitted using the TDMA method. Each transmitter of an activated subscriber station transmits a detectable check signal, so that, on the basis of detection of a check signal in the respective receiver, other, newly activated subscriber stations can determine the presence of transmit signals which are present within a specific, spatially limited range, namely their own respective transmission range. The method according to the invention can be used for transmitting information between terminals in indoor networks in a wireless manner without a central station.

Radio transmission method for digital multimedia data signals between subscriber stations in a local network

The method of the invention is based on an optimum combination of multi-carrier modulation with the spread-spectrum technique. The data of a subscriber station are spread, with the data of a subscriber station being modulated on a set of orthogonal spread sequences and superimposed. The data of a subscriber station are transmitted to a partial quantity of subcarriers in the frequency band, with the partial quantity of sub-carriers associated with the individual subscriber stations being disjunct and distributed over the entire transmission band. A channel estimation required for receiving-side data detection is performed by means of filtering in the time and/or frequency direction of reference symbols. A low-complexity maximum-likelihood sequence estimation is possible for data detection. The method of the invention is well-suited for use for both the upstream and downlinks in future cellular mobile-radio systems.

Method of simultaneous radio transmission of digital data between a plurality of subscriber stations and a base station

For digital transmission of hierarchical HDTV, EDTV and SDTV television signals, on the transmission side after an analog/digital conversion of video and audio input signals and a subsequent removal of redundancy in a source coder, the signal bits are protected in a UEP coder in accordance with their significance. Thereafter, the hierarchically built up television signals (HDTV, EDTV and SDTV) are subjected to a multilevel coding and, combined to form symbols, to a multiresolution modulation and an OFD multiplexing and transmitted after digital/analog conversion. On the receiving side the transmitted signals, after analog/digital reconversion and inverse OED multiplexing (OFDM), are demodulated in a multiresolution demodulator and then decoded in a multistage decoder. Thereupon the data are processed by digital/analog conversion to HDTV, EDTV and SDTV signals in a UEP decoder specific to the respective receiver and a following source decoder.

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Wessling, Germany

Khaled Fazel