Nokia Corporation

Nokia Technologies Oy

Nokia Solutions and Networks Oy

Jari Ylioinas

Olli Piirainen

Kari Juhani Hooli

Markku Juntti

Kai Kiiskilä

Solutions to determine how to form beams when co-operating multiple-input multiple-output antenna panels are used are disclosed. Beams are formed according to sets of beamforming weights corresponding to minimized total transmit power from an antenna array of interest to served terminal devices. Optimization to minimize total transmit power subject to a predefined constraint on a minimum allowable expected value of signal-to-interference-plus-noise ratio, SINR, is performed. In the optimization expected values of SINR for a terminal device are calculated based on based on the sets of beamforming weights for at least the served terminal devices, and weighted second order statistics, wherein a weighting factor for second order statistics between the served terminal devices and the antenna array is one and weighting factors for the other second order statistics less than one. The second order statistics are included in maintained channel state information.

Interference aware eigen-beamforming based on second order statistics

According to an aspect, there is provided an apparatus for performing beamforming optimization for a MIMO architecture. The apparatus maintains, in a database, channel state information of a plurality of radio channels comprising first and second order statistics. The apparatus calculates, separately for each of two or more remote radio units using an eigenbeamforming scheme, first sets of beamforming weights based on the second order statistics. Then, the apparatus performs, for each terminal device, single-user MIMO optimization between the two or more remote radio units to maximize a pre-defined metric, being a mutual information metric or signal-to-interference-plus-noise, based on first sets of beamforming weights and the first order statistics. The result, for each terminal device, is a second set of beamforming weights. The apparatus causes transmitting data using beams formed by applying both first and second sets of optimized beamforming weights at the two or more remote radio units.

Method and an apparatus for a transmission scheme

Disclosed is a chip-level or a symbol-level equalizer structure for a multiple transmit and receiver antenna architecture system that is suitable for use on the WCDMA downlink. The equalizer structure takes into account the difference in the natures of inter-antenna interference and multiple access interference and suppresses both inter-antenna interference and multiple access interference (MAI). Enhanced receiver performance is achieved with a reasonable implementation complexity. The use of the CDMA receiver architecture, in accordance with this invention, enables the realization of increased data rates for the end user. The CDMA receiver architecture can also be applied in conjunction with space-time transmit diversity (STTD) system architectures.

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Oulu, Finland

Jari Ylioinas