Siemens Aktiengesellschaft

Other

Eduard Jorswieck

Thomas Haustein

Volker Jungnickel

Egon Schulz

Martin Weckerle

Rüdiger Halfmann

Clemens Von Helmolt

Gerhard Wunder

Udo Krueger

Volker Pohl

Clemens V Helmolt

In an OFDM multi carrier modulation method, M sub-carriers are used in a frequency band of a broadband mobile radio channel and several symbols are used in a time band. With application of a MIMO multi-antenna method with T transmitting antennae and R receiving antennae, for all sub-carriers and all symbols, a single, pre-determined, channel-matched transmission strategy is used, which is described by a maximum of T*R complex values on the signal side, independent of the species of the MIMO multi-antenna method and independent of the size of the frequency/time bands.

Method for digital wireless message transmission over a broadband mobile radio channel

A bidirectional signal processing method uses parallel transmission of digital transmitted data streams in a multiple input-multiple output system. Related art methods generate high bit error rates mostly in singular transmission channels. For this reason, the rank-adaptive signal processing method provides that the number nof active subchannels are varied according to the actual channel behavior in order to effect a robust data transmission even in singular radio channels based on a transmit-side and receive-side channel knowledge and a modification of the data vector by a linear matrix vector multiplication while introducing a factor gamma for limiting the maximum transmit power. The maximum transmit power is then only distributed to the currently activated subchannels so that no transmit power remains unused. Another optimization of the number of subchannels noccurs when selecting the modulation and encoding methods. During the optimal rank-adaptation according to the water-filling principle, another power is allocated to each subchannel. Another modulation and encoding method is accordingly selected for each data stream. During the suboptimal rank-adaptation according to the channel inversion principle, all subchannels have the same power whereby enabling the data streams to be modulated and encoded in a common source.

MIMO signal processing method involving a rank-adaptive matching of the transmission rate

The invention relates to a signal processing method which optimizes the bit error rate under pragmatic conditions. The signalling method is optimally matched to the radio channel, variable with time, in rapid sequence by means of linear operations. Uplink and downlink transmission sides are determined by an excess of antennae on the downlink transmission side. The estimations of the channel matrix in the one transmission direction, necessary for the matching of the transmitter, can, in the absence of common-channel distortions with the condition of channel reciprocity, be directly obtained from the estimations for the other transmission direction. By a suitable linear combination of the transmission signals and, optionally, also the received signals, an error-free bi-directional transmission of data streams can be achieved in Rayleigh and Rice channels with significantly lower transmission powers than in purely receiver-side linear signal processing.

Adaptive signal processing method in a MIMO-system

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Berlin, Germany

Eduard Jorswieck