Abstract: A method performed by a base station of enabling a User Equipment, UE, to determine a precoder codebook in a wireless communication system is provided. The base station transmits (303) to the UE, information regarding precoder parameters enabling the UE to determine the precoder codebook. The precoder parameters are associated with a plurality of antenna ports of the base station. The precoder parameters relate to a first dimension and a second dimension of the precoder codebook. The plurality of antenna ports comprises a number NT of antenna ports that is a function of a number Nh of antenna ports in the first dimension, and a number Nv of antenna ports in the second dimension.

Abstract: A method in a radio communications network, the network comprising a base station and at least one user equipment, UE, wherein the base station comprises an antenna array comprising a plurality of antenna elements, the method being implemented in the base station and comprising the steps of precoding (1101) a multi-dimensional channel state information reference signal, CSI-RS, with a precoding virtualization matrix such that each antenna element of the antenna array is associated with a non-zero weight in at least two precoders of the precoding virtualization matrix, transmitting (1102) the multi-dimensional channel state information reference signal to a UE, receiving (1103) an identifier from the UE, wherein the identifier identifies a selected precoder from a codebook using (1104) the selected precoder to identify a desired precoder and transmitting (1105) a data signal to the UE using the desired precoder.

Abstract: A method of determining a precoder from a first codebook, where said precoder determination comprises measuring on a set of beamformed antenna ports, and where the precoders in the first codebook share one or more common components with precoders in a second, multi-beam, codebook and where determining precoders from the second codebook comprises measuring on a larger set of, typically non-precoded, antenna ports.

Abstract: A transmitting radio node (10) precodes a transmission from a one-dimensional antenna array (12) to a receiving radio node (50). The array (12) includes co-polarized antenna elements (14) aligned in the array's only spatial dimension. The transmitting radio node (10) precodes the transmission from each of different subarrays (34a, 34b) of the antenna elements (14) using a coarse-granularity precoder that is factorizable from a multi-granular precoder targeting the given spatial dimension of the array (12) at different granularities, so as to virtualize the subarrays (34a, 34b) as different auxiliary elements (38a, 38b). The transmitting radio node (10) also precode the transmission from the different auxiliary elements (38a, 38b) using one or more finer-granularity precoders that are also factorizable from the multi-granular precoder. In this case, the coarse granularity precoders and the one or more finer-granularity precoders are represented within one or more codebooks (26) used for said precoding.

Abstract: A transmitting radio node precodes a transmission from an antenna array to a receiving radio node. The array includes co-polarized antenna elements aligned in a given spatial dimension of the array. The transmitting radio node precodes the transmission from different subarrays of the antenna elements using respective coarse-granularity precoders that are factorizable from a multi-granular precoder targeting the given spatial dimension of the array at different granularities, so as to virtualize the subarrays as different auxiliary elements. The transmitting radio node also precode the transmission from the different auxiliary elements using one or more finer-granularity precoders that are also factorizable from the multi-granular precoder.

Abstract: A method performed by a network node for enabling Interference Alignment, IA, of transmissions to user equipments is provided. The network node receives signal strength values associated with more than one network node for the user equipments, wherein each signal strength value is associated with one network node. Then, the network node schedules a first group of the user equipments on radio transmission resources that are orthogonal to radio transmission resources of at least one other group of the user equipments when an IA gain value for each user equipment in the first group passes a threshold level. The IA gain value is determined by the network node based on the received signal strength values. The network node may then enable IA of transmissions to the scheduled first group of user equipments from at least two network nodes capable of performing IA of transmissions.

Abstract: There is disclosed a method for operating a transmitting node of a wireless communication network, the transmitting node being adapted for a plurality of beamforming states, wherein the method comprises transmitting reference signaling based on a beamforming state of the transmitting node. There are also disclosed related nodes and methods.

Abstract: A transmitting radio node (10) precodes a transmission from an antenna array (12) to a receiving radio node (50). The array (12) includes co-polarized antenna elements (14) aligned in a given spatial dimension of the array (12). The transmitting radio node (10) precodes the transmission from different subarrays (34a, 34b) of the antenna elements (14) using respective coarse-granularity precoders that are factorizable from a multi-granular precoder targeting the given spatial dimension of the array (12) at different granularities, so as to virtualize the subarrays (34a, 34b) as different auxiliary elements (38a, 38b). The transmitting radio node (10) also precode the transmission from the different auxiliary elements (38a, 38b) using one or more finer-granularity precoders that are also factorizable from the multi-granular precoder. In this case, the coarse granularity precoders and the one or more finer-granularity precoders are represented within one or more codebooks (26) used for said precoding.

Abstract: A method in a network node for selecting a beam candidate in a wireless communication network, including acquiring information including information indicative of signal qualities for multiple beam candidates; assigning to each of the multiple beam candidates a factor indicating signal interference generated by the corresponding beam candidate and selecting a beam candidate taking into account at least the associated signal quality and the factor assigned to the selected beam candidate.

Abstract: A network node (10) signals to a wireless communication device (14) which precoders in a codebook are restricted from being used. The network node (10) in this regard generates codebook subset restriction signaling that, for each of one or more groups of precoders, jointly restricts the precoders in the group by restricting a certain component (e.g., a certain beam precoder) that the precoders in the group have in common. This signaling may be for instance rank-agnostic signaling that jointly restricts the precoders in a group without regard to the precoders' transmission rank. Regardless, the network node (10) sends the generated signaling to the wireless communication device (14).

Abstract: A transmitting radio node (10) precodes a transmission from an antenna array, which includes antenna elements arranged along at least two axes, using a main codebook which is representable as a Kronecker product of a first codebook and a second codebook, where the first codebook comprises predetermined sub-precoders and the second codebook comprises configurable sub-precoders. A receiving radio node (20) may benefit from adaptive beamforming made possible by the configurability of the main codebook, while still using a stable format, which remains valid also after reconfiguration, for the exchange of reference signals and corresponding feedback information.

Abstract: There is disclosed a method for operating a MIMO transmitting node (100) for a wireless communication network. The method comprises configuring a receiving node (10) for determining CSI feedback for a first number Ncsi_ports of separate CSI-RS ports, the first number Ncsi_ports being smaller than a second number Nports of ports used for data transmission to the receiving node (10), wherein configuring comprises signaling the first number Ncsi_ports and the second number Nports to the receiving node (10). The disclosure also pertains to related methods and devices.

Abstract: The present disclosure pertains to a method for operating a network node (100) for a wireless communication network, the method comprising providing CSI-RS signaling, the method further comprising signaling a power boost indication for the CSI-RS signaling. The disclosure also pertains to related devices and methods.

Abstract: The present invention relates to a network node and a method performed by the network node for controlling communication between a radio base station, RBS, and user equipments, UEs. The RBS has multiple antennas and uses beam forming when communicating with the UEs. The method comprises obtaining (702) information on an expected first propagation path direction interval between the RBS and UEs served by other neighboring RBSs, and obtaining (704) information on an expected second propagation path direction interval between the RBS and served UEs; defining (706) a first communication power limit for each of a plurality of beams according to the obtained information, the first limit being defined to suppress communication power in the first propagation path direction interval, when the plurality of beams are transmitted; and determining (708) antenna weights for each of the plurality of beams based on the defined first communication power limit.

Abstract: There is provided mechanisms for precoding over a beam subset. A method is performed by a network node. The method comprises exchanging reference signal information for a set of transmission beams or set of antenna ports with a wireless device. The method comprises acquiring, based on the reference signal information, information regarding which proper subset of transmission beams from the set of transmission beams to use for communication with the wireless device.

Abstract: There is disclosed a method of operating a transmitter arrangement for a wireless communication network, the transmitter arrangement adapted for beamforming. The method comprises determining a maximum power level mask for the power of transmission and/or beams in a critical angular interval, the maximum power level mask covering at least the critical angular interval and controlling beamforming based on the maximum power level mask.

Abstract: A transmitting radio node (10) precodes a transmission from an antenna array (12)to a receiving radio node (50). The array (12) includes co-polarized antenna elements (14) aligned in a given spatial dimension of the array (12). The transmitting radio node (10) precodes the transmission from different subarrays (34a, 34b) of the antenna elements (14) using respective coarse-granularity precoders that are factorizable from a multi-granular precoder targeting the given spatial dimension of the array (12) at different granularities, so as to virtualize the subarrays (34a, 34b) as different auxiliary elements (38a, 38b). The transmitting radio node (10) also precode the transmission from the different auxiliary elements (38a, 38b) using one or more finer-granularity precoders that are also factorizable from the multi-granular precoder.

Abstract: A method performed by a base station of enabling a User Equipment, UE, to determine a precoder codebook in a wireless communication system is provided. The base station transmits (303) to the UE, information regarding precoder parameters enabling the UE to determine the precoder codebook. The precoder parameters are associated with a plurality of antenna ports of the base station. The precoder parameters relate to a first dimension and a second dimension of the precoder codebook. The plurality of antenna ports comprises a number NT of antenna ports that is a function of a number Nh of antenna ports in the first dimension, and a number Nv of antenna ports in the second dimension.

Abstract: A transmitting radio node (10) precodes a transmission from an antenna array, which includes antenna elements arranged along at least two axes, using a main codebook which is representable as a Kronecker product of a first codebook and a second codebook, where the first code-book comprises predetermined sub-precoders and the second codebook comprises configurable sub-precoders.

Abstract: A method performed by a network node for enabling Interference Alignment, IA, of transmissions to user equipments is provided. The network node receives signal strength values associated with more than one network node for the user equipments, wherein each signal strength value is associated with one network node. Then, the network node schedules a first group of the user equipments on radio transmission resources that are orthogonal to radio transmission resources of at least one other group of the user equipments when an IA gain value for each user equipment in the first group passes a threshold level. The IA gain value is determined by the network node based on the received signal strength values. The network node may then enable IA of transmissions to the scheduled first group of user equipments from at least two network nodes capable of performing IA of transmissions.