Abstract: A third neural network (1503c) supports provision of an optimized action, belonging to a continuous action space, for application in a wireless communication network (1000) to affect data transmission over a communication channel (530; 730; 1030). It is based on a combination of a trained first neural network (1503a) and a trained second neural network (1503b). The first neural network (1503a) trained to, based on state information, indicative of a state relating to at least the communication channel (530; 730; 1030), as input, provide action values as output. The action values being associated with intermediate actions, respectively, of a finite set of actions belonging to a discrete action space. The second neural network (1503b) trained to transform action values associated with said intermediate actions, respectively, to a corresponding optimized action belonging to said continuous action space.

Abstract: Methods performed by network nodes in a radio access network may be provided. A first network node may receive an identification of data models supported by a second network node. Each of the identified data models may include a data model for calculating a compact representation of data collected, at least one correlation parameter, and an accuracy metric. The first network node may transmit a request that the second network node calculate an identified one of the data models. The first network node may receive the calculated data model from the second network node. The first network node may evaluate the received calculated data model based on determining whether the received calculated data model correlates to at least one correlation parameter.

Abstract: In certain embodiments, a method performed by a wireless device comprises estimating a channel state of a downlink channel and transmitting a CSI report for the downlink channel based on the channel state. The CSI report indicates a plurality of precoder vectors, each corresponding to a frequency sub-band of the bandwidth of the downlink channel, a precoder vector being expressed as a linear combination of spatial-domain components and frequency-domain component wherein each of the spatial-domain components is associated with a respective set of one or more frequency-domain components.

Abstract: A method performed by a wireless device (510, 800, 1200) for reporting channel state information (CSI) for a downlink channel is disclosed. The method comprises transmitting (601, 705) a CSI report for the downlink channel to a network node (560, 1100), the CSI report comprising: a set of reported coefficients; an indication of how the network node is to interpret the set of reported coefficients; and an indication of a payload size of the set of the reported coefficients.

Abstract: Embodiments include methods for operating a network node in a wireless network. Such embodiments include applying non-linear precoding to a first data stream to remove a representation of expected inter-stream interference due to a second data stream, thereby generating a corrected first data stream. Such embodiments also include applying linear precoding to the corrected first data stream and to a first reference signal (RS) stream to generate a first signal layer, wherein the first RS stream is not corrected for the expected inter-stream interference prior to applying the linear precoding. Such embodiments also include transmitting the first signal layer to a user equipment (UE). Other embodiments include complementary methods performed by a UE, as well as network nodes and UEs configured to perform operations corresponding to such methods.

Abstract: In certain embodiments, a method performed by a wireless device comprises estimating a channel state of a downlink channel and transmitting a CSI report for the downlink channel based on the channel state. The CSI report indicates a plurality of precoder vectors, each corresponding to a frequency sub-band of the bandwidth of the downlink channel, a precoder vector being expressed as a linear combination of spatial-domain components and frequency-domain component wherein each of the spatial-domain components is associated with a respective set of one or more frequency-domain components.

Abstract: A method performed by a wireless device for transmitting a channel state information (CSI) report for a downlink channel comprises obtaining a first set of candidate frequency-domain components and determining a set of spatial-domain components. The method comprises determining a second set of candidate frequency-domain components as a subset of the first set of candidate frequency-domain components. The method comprises determining, for each spatial-domain component of the set of spatial-domain components, a spatial-domain component-specific set of frequency-domain components as a subset of the second set of candidate frequency-domain components. The method comprises transmitting, to a network node, the CSI report.

Abstract: The present disclosure relates to a method performed by a wireless node (100) for transmitting reference symbols, the node comprising an antenna with a plurality of antenna ports, the method comprising configuring channel state information, CSI, measurements of a user equipment, UE (110), by transmitting a downlink message, transmitting a first reference symbol using the plurality of antenna ports, wherein the first reference symbol is transmitted using a first number N of antenna ports, transmitting a second reference symbol using the plurality of antenna ports, wherein the second reference symbol is transmitted using a second number K of antenna ports, wherein the first reference symbol is transmitted using a first port distance smaller than a second port distance used when transmitting the second reference symbol, and wherein the K used antenna ports are less than the N used antenna ports.

Abstract: A method performed by a wireless device (510, 700, 1000) for transmitting a channel state information (CSI) report for a downlink channel comprises obtaining (601) a first set of candidate frequency-domain components and determining (602) a set of spatial-domain components. The method comprises determining (603) a second set of candidate frequency-domain components as a subset of the first set of candidate frequency-domain components. The method comprises determining (604), for each spatial-domain component of the set of spatial-domain components, a spatial-domain component-specific set of frequency-domain components as a subset of the second set of candidate frequency-domain components. The method comprises transmitting (605), to a network node (560, 900), the CSI report.

Abstract: A method performed by a wireless device (510, 800, 1200) for reporting channel state information (CSI) for a downlink channel is disclosed. The method comprises transmitting (601, 705) a CSI report for the downlink channel to a network node (560, 1100), the CSI report comprising: a set of reported coefficients; an indication of how the network node is to interpret the set of reported coefficients; and an indication of a payload size of the set of the reported coefficients.

Abstract: In certain embodiments, a method performed by a wireless device comprises estimating a channel state of a downlink channel and transmitting a CSI report for the downlink channel based on the channel state. The CSI report indicates a plurality of precoder vectors, each corresponding to a frequency sub-band of the bandwidth of the downlink channel, a precoder vector being expressed as a linear combination of spatial-domain components and frequency-domain component wherein each of the spatial-domain components is associated with a respective set of one or more frequency-domain components.

Abstract: A method performed by a wireless device (510, 700, 1100) is disclosed. The wireless device obtains (601) a configuration for a sub-band channel quality indicator (CQI) granularity and a sub-band precoding matrix indicator (PMI) granularity for the wireless device. The wireless device determines (602) channel state information (CSI) feedback according to the configured sub-band CQI granularity and the sub-band PMI granularity. The sub-band PMI granularity corresponds to a first sub-band size and the sub-band CQI granularity corresponds to a second sub-band size. The first sub-band size is smaller than the second sub-band size. The wireless device transmits (603), to a network node (560, 1000), the determined CSI feedback.

Abstract: A method performed by a wireless device (510, 700, 1100) is disclosed. The wireless device obtains (601) a configuration for a sub-band channel quality indicator (CQI) granularity and a sub-band precoding matrix indicator (PMI) granularity for the wireless device. The wireless device determines (602) channel state information (CSI) feedback according to the configured sub-band CQI granularity and the sub-band PMI granularity. The sub-band PMI granularity corresponds to a first sub-band size and the sub-band CQI granularity corresponds to a second sub-band size. The first sub-band size is smaller than the second sub-band size. The wireless device transmits (603), to a network node (560, 1000), the determined CSI feedback.

Abstract: There are provided mechanisms for beam forming using an antenna array comprising dual polarized elements. A method comprises generating one or two beam ports. The one or two beam ports are defined by combining at least two non-overlapping subarrays. Each subarray has two subarray ports. The two subarray ports have identical power patterns and mutually orthogonal polarizations. The at least two non-overlapping subarrays are combined via expansion weights. The expansion weights and map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays. At least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe. The method comprises transmitting signals using said one or two beam ports.

Abstract: A method performed by a wireless device (510, 700, 1000) for transmitting a channel state information (CSI) report for a downlink channel comprises obtaining (601) a first set of candidate frequency-domain components and determining (602) a set of spatial-domain components. The method comprises determining (603) a second set of candidate frequency-domain components as a subset of the first set of candidate frequency-domain components. The method comprises determining (604), for each spatial-domain component of the set of spatial-domain components, a spatial-domain component-specific set of frequency-domain components as a subset of the second set of candidate frequency-domain components. The method comprises transmitting (605), to a network node (560, 900), the CSI report.

Abstract: There are provided mechanisms for beam forming using an antenna array comprising dual polarized elements. A method comprises generating one or two beam ports. The one or two beam ports are defined by combining at least two non-overlapping subarrays. Each subarray has two subarray ports. The two subarray ports have identical power patterns and mutually orthogonal polarizations. The at least two non-overlapping subarrays are combined via expansion weights. The expansion weights and map the one or two beam ports to subarray ports such that the one or two beam ports have the same power pattern as the subarrays. At least some of the expansion weights have identical non-zero magnitude and are related in phase to form a transmission lobe. The method comprises transmitting signals using said one or two beam ports.

Abstract: A method for managing channel state information in a wireless communication system comprises obtaining a base set of channel state information of a channel between a first node and a second node based on at least one transmission signal. A dedicated reference signal, specific for a limited set of nodes comprising the second node is transmitted within a channel subspace selected in dependence of the obtained base set of channel state information. At least one common channel state information reference signal specific for an intended coverage area of the first node is transmitted. The common channel state information reference signal allows for obtaining a fall-back set of channel state information of a channel between the first node and the second node. The fall-back set of channel state information represents coarser granularity, in spatial dimensions, than the base set of channel state information.

Abstract: There is provided mechanisms for beamforming using an antenna array. A method is performed by a network node. The method comprises obtaining, from a wireless device, a precoding matrix indicator to be used for transmission to the wireless device. The method comprises selecting a codebook from a set of codebooks according to the received indicator, wherein the selected codebook defines the precoding matrix, and wherein the set of codebooks comprises codebooks defining variable beam widths and having same number of non-zero antenna weights for all beam widths. The method comprises precoding transmission of signals to the wireless device from the antenna array using the selected codebook.

Abstract: A method for managing channel state information in a wireless communication system comprises obtaining a base set of channel state information of a channel between a first node and a second node based on at least one transmission signal. A dedicated reference signal, specific for a limited set of nodes comprising the second node is transmitted within a channel subspace selected in dependence of the obtained base set of channel state information. At least one common channel state information reference signal specific for an intended coverage area of the first node is transmitted. The common channel state information reference signal allows for obtaining a fall-back set of channel state information of a channel between the first node and the second node. The fall-back set of channel state information represents coarser granularity, in spatial dimensions, than the base set of channel state information.

Abstract: A system and method of creating a “gap” in a network node's angular power profile to reduce the amount of inter-cell interference generated at certain critical directions. A plurality of network nodes may jointly derive the “gap” in the angular power profile of each of them. A transmitting node may rely on Discovery Reference Signal, DRS, based Reference Signal Received Power, RSRP, measurements of its beams from a neighboring node, which signals an interference metric for each beam indicating a relative beam interference level. The transmitting node utilizes the signaled metrics to determine which beams are causing undesirable interference and are to be removed from its set of candidate beams to create a “gap” in its angular power profile. The remaining candidate beams are used by the transmitting network node for subsequent directional data transmissions. Instead of this distributed approach, a central node-based beam removal approach may be implemented.