Abstract: There is provided a method comprising: determining a phase difference between at least two antenna units of a distributed antenna system on the basis of at least one pilot signal received from at least one of a plurality of antenna units; and transmitting phase correction commands to a common base station of the plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between at least two antenna units of the distributed antenna system.

Abstract: There is provided a method comprising: determining a phase difference between at least two antenna units of a distributed antenna system on the basis of at least one pilot signal received from at least one of a plurality of antenna units; and transmitting phase correction commands to a common base station of the plurality of antenna units on the basis of the determined phase difference in order to synchronize carrier phases between at least two antenna units of the distributed antenna system.

Abstract: The invention is related to a data loading method in a communication system where sub-carriers include eigenmodes, comprising, for instance: arranging eigenmodes into a predetermined number of clusters, each cluster comprising eigenmodes of different quality levels; pre-allocating transmission power to the eigenmodes with the aid of the calculated required power for achieving the approximated signal-to-noise ratio; determining collective transmission power to be allocated to each cluster based on the pre-allocation; allocating collective transmission power to the eigenmodes.

Abstract: A solution for optimizing beamforming configurations and transmit power allocation configurations in a telecommunication system comprising a base station and a plurality of user entities is provided. The base station and the user entities are capable of multiple-input multiple-output (MIMO) communications, i.e. capable of communicating through spatial subchannels. The base station calculates iteratively optimal beamforming configurations for the base station and for each user entity and transmit power allocation configurations for each spatial subchannel used in MIMO communications. The base station carries out the calculation on the basis of channel state information received from the user entities by utilizing the information on correlation of different spatial subchannels, i.e. interference between the subchannels, in order to update beamforming configurations and transmit power allocation configurations.

Abstract: A data transmission method utilizing time division duplex between a first and a second transceiver is provided. The first transceiver transmits a signal to the second transceiver using given transmission parameters. The second transceiver estimates a signal quality metric from the signal, the metric depicting signal quality degradation caused by interference. The second transceiver compares the estimated metric to a target metric, determines an offset value on the basis of the comparison, and transmits the offset value to the first transceiver, which adjusts transmission parameters on the basis of the offset value, and transmits a signal to the second transceiver using the adjusted transmission parameters.

Abstract: The invention is related to a data loading method in a communication system where sub-carriers include eigenmodes, comprising, for instance: arranging eigenmodes into a predetermined number of clusters, each cluster comprising eigenmodes of different quality levels; pre-allocating transmission power to the eigenmodes with the aid of the calculated required power for achieving the approximated signal-to-noise ratio; determining collective transmission power to be allocated to each cluster based on the pre-allocation; allocating collective transmission power to the eigenmodes.