Abstract: Disclosed is a mobile terminal device and a radio base station apparatus capable of effectively feeding back PMIs by selecting a precoder using double codebooks W1 and W2 in downlink MIMO transmission. The mobile terminal device includes a feedback control signal generating section that individually performs channel coding for the first PMI selected from the first codebook for wideband/long-period and the second PMI selected from the second codebook for subband/short-period and a transmit section that transmits the individually channel-coded first and second PMIs to the radio base station apparatus on a physical uplink shared channel (PUSCH).

Abstract: A method for reducing interference at a terminal of a wireless cellular network is described. The terminal experiences interference from a plurality of interfering nodes in the wireless cellular network. The method includes selecting the precoders of the interfering nodes such that the sum of distances between the interference projector matrices for the terminal is minimized.

Abstract: An apparatus for scheduling transmission resources to users served by a base station equipped with a plurality of antennas includes a predictor for predicting rate regions for one or more future time slots based on rate regions for one or more past time slots to obtain one or more predicted rate regions, and a processor for calculating the transmission resources for the users for a current time slot using scheduled transmission resources for the one or more past time slots, a rate region for the current time slot and the one or more predicted rate regions.

Abstract: A transmission filter calculator for calculating at least a transmit filter for communication from a multi-antenna transmit communication device to a multi-antenna receive communication device via a multiple-input-multiple-output (MIMO) channel iteratively determines transmit filters for multiple data streams.

Abstract: An apparatus for allocating resources to nodes in a communication system comprises an iteration controller (10) for performing an iterative processing, the iteration controller being configured for using (11) iteration resource weights to obtain a resources allocation result for an iteration step, and for updating (12) the iteration resource weights to obtain updated iteration resource weights for a further iteration step using a weighted combination of the resources allocation results for the iteration step and for at least one earlier iteration step.

Abstract: A data transmission method includes, in the mobile station apparatus, selecting a PMI and an RI corresponding to an Hermitian transpose of a channel matrix indicative of channel characteristics and calculating a CQI from the PMI. The method further includes transmitting the PMI, the RI, and the CQI to the base station apparatus as feedback information. The method further includes, in the base station apparatus, calculating a first data rate of a case of performing SU-MIMO transmission based on the PMI transmitted from the mobile station apparatus as feedback and calculating a second data rate of a case of performing ZF MU-MIMO transmission based on the PMI. The method further includes selecting a transmission scheme corresponding to a higher data rate between the first and second data rates.

Abstract: An apparatus for calculating receive parameters for an MIMO system including a plurality of individual transmission sections, a transmission section having a transmit circuit adjustable by a transmit parameter, and a plurality of individual users, a user having a receive circuit being adjustable by a receive parameter, includes a calculator for calculating a receive parameter for a first selected data stream for a first user of the plurality of users using a channel information for a transmission channel between the user and a first individual transmit section, to which the user is associated, and for calculating a receive parameter for a second selected data stream for a second user of the plurality of users associated with a second different individual transmission section using channel information between the first user and the second transmission section the second user is associated with, or using the calculated receive parameter for the first user.

Abstract: In a wireless communication system where the data transmission is optimized with respect to the channel state information fed back by the users, a service degradation attack can be made by feeding back faked channel state information. A method for preventing a service degradation attack on a first wireless communication device by a second wireless communication device in a wireless communication system, said method comprising: verifying by a base station whether the channel state information sent to the base station by the second wireless communication device corresponds to its real channel.

Abstract: In a method for determining a precoding matrix for precoding symbols to be transmitted to a plurality of wireless devices by a node of a wireless communication system the precoding matrix comprises a precoding vector for each wireless device of a plurality of wireless devices, each precoding vector having a precoding element for each transmit antenna of the node. Each precoding element represents a phase shifter for phase shifting a phase of a symbol to be transmitted. A plurality of interference strength indicators for different phase angles is calculated based on the precoding matrix. Further, for the precoding element of the precoding vector a phase angle is selected which corresponds to a calculated interference strength indicator fulfilling a predefined interference strength criterion.

Abstract: A method for determining for a plurality of users of a wireless cellular network transmitters of the wireless cellular network used for determining candidate rate configurations for serving the users is described, wherein the transmitters of the wireless cellular network operate in accordance with the fractional reuse scheme allocating distinct resource blocks to respective transmitter partitions, each partition including transmitters having assigned the same resource block, and wherein for each user, an active transmitter set is determined by selecting from each transmitter partition a transmitter as an active transmitter in accordance with a predefined criterion.

Abstract: A method for determining a precoding vector for precoding data to be transmitted to a wireless device, includes receiving first channel state information of a channel between a first wireless device and a first base station. The first channel state information is received by the first base station from the first wireless device. The method includes receiving first channel gain information of a channel between a second wireless device and the first base station. The first channel gain information is received from the second base station. The method includes receiving a first signal strength parameter from the second base station and a first interference strength parameter from the second base station and maximizing a common signal to interference noise ratio parameter to obtain a precoding vector for precoding data to be transmitted to the first wireless device.

Abstract: To increase a data rate irrespective of whether the spatial correlation between channels is high or low, while ensuring compatibility with the LTE-scheme MIMO system, in a MIMO system in which a base station apparatus (eNode B) switches between SU-MIMO transmission and ZF MU-MIMO transmission based on feedback information from a mobile station apparatus (UE) to perform data transmission, the mobile station apparatus (UE) selects a PMI and an RI corresponding to an Hermitian transpose of a channel matrix indicative of channel characteristics, calculates a CQI from the PMI, and transmits the PMI, RI and CQI as feedback, and the base station apparatus (eNode B) calculates a first data rate of the case of performing SU-MIMO transmission and a second data rate of the case of performing ZF MU-MIMO transmission based on the PMI that is fed back, and selects a transmission scheme corresponding to a higher data rate between the first and second data rates.

Abstract: In a method for determining a precoding matrix for precoding symbols to be transmitted to a plurality of wireless devices by a node of a wireless communication system the precoding matrix comprises a precoding vector for each wireless device of a plurality of wireless devices, each precoding vector having a precoding element for each transmit antenna of the node. Each precoding element represents a phase shifter for phase shifting a phase of a symbol to be transmitted. A plurality of interference strength indicators for different phase angles is calculated based on the precoding matrix. Further, for the precoding element of the precoding vector a phase angle is selected which corresponds to a calculated interference strength indicator fulfilling a predefined interference strength criterion.

Abstract: A transmission filter calculator for calculating at least a transmit filter for communication from a multi-antenna transmit communication device to a multi-antenna receive communication device via a MIMO channel iteratively determines transmit filters for multiple data streams. The transmission filter calculator chooses a transmit filter in a given iteration such that the transmit filter is orthogonal to one or more transmit filters chosen in one or more previous iterations, and such that a weighted or unweighted transmission rate obtainable using the transmit filter chosen in the given iteration is maximized, and chooses the transmit filter in dependence on a matrix product term which is based on a channel matrix describing MIMO channel characteristics between the transmit communication device and a currently considered one of the receive communication devices and on a distortion covariance matrix describing a noise, an inter-cell interference and an upper limit of an intra-cell interference.

Abstract: A method for reducing interference at a terminal of a wireless cellular network is described. The terminal experiences interference from a plurality of interfering nodes in the wireless cellular network. The method includes selecting the precoders of the interfering nodes such that the sum of distances between the interference projector matrices for the terminal is minimized.

Abstract: To facilitate selection of an optimal PMI corresponding to a channel variance in a channel propagation path, in a method of controlling codebooks comprised of a plurality of DFT codebooks for defining precoding matrixes that are selected when correlation between antennas in a base station apparatus (eNode B) is high and a plurality of random codebooks for defining precoding matrixes that are selected when correlation between antennas in the base station apparatus (eNode B) is low, a channel variance in a channel propagation path is estimated, and based on the estimated channel variance, the configuration ratio between the DFT codebooks and the random codebooks included in the codebooks is varied adaptively.

Abstract: Disclosed is a mobile terminal device and a radio base station apparatus capable of effectively feeding back PMIs by selecting a precoder using double codebooks W1 and W2 in downlink MIMO transmission. The mobile terminal device includes a feedback control signal generating section that individually performs channel coding for the first PMI selected from the first codebook for wideband/long-period and the second PMI selected from the second codebook for subband/short-period and a transmit section that transmits the individually channel-coded first and second PMIs to the radio base station apparatus on a physical uplink shared channel (PUSCH).

Abstract: The receiver includes a signal determiner, a soft information determiner and a soft information decoder. The signal determiner determines a complex receive value for the receive signal received from a relay station. Further, the soft information determiner obtains a soft information represented by a combination of a first probability value and a second probability value. The first probability value is derivable by adding a value depending on an overall probability density function for each symbol of a modulation alphabet including a same first bit value at a same bit position of the symbols, wherein each symbol of the modulation alphabet represents at least two bits.

Abstract: A method for determining a quantized channel vector in a terminal of a Multiple Input Multiple Output communication system includes determining a channel quality of a channel between a base station and the terminal and determining the quantized channel vector from a plurality of quantized channel vectors based on the determined channel quality. The determined quantized channel vector provides a predefined channel property value.

Abstract: A spatial sub-channel selection and pre-coding apparatus for being operative in a first communication device, the first communication device being adapted for communicating with a second and a third communication device using MIMO (Multiple-Input-Multiple-Output) radio channels, a first MIMO radio channel extending between the first communication device and the second communication device having at least one spatial sub-channel, a second MIMO radio channel extending between the first communication device and the third communication device having at least one spatial sub-channel, wherein one of the first MIMO radio channel or the second MIMO radio channel has at least two spatial sub-channels.