Abstract: Embodiments include methods for a radio access network (RAN) node configured to serve one or more user equipment (UEs). Such methods include transmitting reference signals (RS) for a downlink (DL) channel and receiving, from a UE, a report including encoded feedback representing the DL channel. The encoded feedback comprises a UE DL channel estimate mapped to a channel feature set based on a first mapping that is proprietary to the UE. The channel feature set is compressed based on a second mapping that is known by the UE and the RAN node. Such methods also include, using a decoder function of a neural-network autoencoder (NNAE), decoding the encoded feedback to obtain a reconstruction of the channel feature set. Other embodiments include complementary methods for a UE, as well as RAN nodes and UEs configured to perform such methods.

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. 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: Embodiments include methods for a radio access network (RAN) node. Such methods include transmitting downlink (DL) reference signals (RS) in accordance with one or more configurations and receiving, from each of one or more user equipment (UEs), feedback representing a DL channel from the RAN node to the UE. The feedback is based on the UE's measurements of the transmitted DL RS and is encoded by one or more UE encoders that correspond to respective RAN node decoders. Such methods include, for each of the one or more UEs, obtaining one or more measurements of uplink (UL) RS transmitted by the UE in accordance with the one or more configurations. Such methods include training the RAN node decoder(s) based on the received feedback and the obtained UL RS measurements. Other embodiments include complementary methods for UEs, as well as RAN nodes and UEs configured to perform such methods.

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: There is provided mechanisms for transmission of reference signals. A method is performed by a terminal device. The terminal device comprises at least two physical antenna ports. The method comprises creating a virtual antenna port for, and applied over, at least two of the physical antenna ports. The method comprises transmitting, in the virtual antenna port, as many uplink reference signals as there are physical antenna ports.

Abstract: In a first method, a wireless device estimates a delay profile of a channel impulse response, CIR, for a channel between a network node and the wireless device, compresses the delay profile using a compression function, and transmits the compressed delay profile. The compression function includes a first function and a quantizer. The first function is configured to receive input data and reduce a dimension of the input data. In a second method, a network node receives a compressed delay profile of CIR for a channel between a network node and a wireless device, decompresses the compressed delay profile using a decompression function, and estimates a position of the wireless device based on at least the decompressed delay profile. The decompression function includes a first function which is configured to receive input data and provide output data in a higher dimensional space than the input data.

Abstract: There is provided mechanisms for transmission of reference signals. A method is performed by a terminal device. The terminal device comprises at least two physical antenna ports. The method comprises obtaining channel information. The method comprises determining, for at least one given precoder in a codebook, an uplink reference signal to physical antenna port mapping based on the channel information. The method comprises transmitting uplink reference signals in the physical antenna ports according to the determined mapping.

Abstract: The disclosure includes a host operating in a communication system to provide an over-the-top (OTT) service. The host includes processing circuitry configured to initiate transmission of user data to a network node in a cellular network to a user equipment (UE). The network node is configured to receive a CSI report for a downlink channel from a wireless device and transmit the user data from the host to the UE to provide the OTT service based on the CSI report. The CSI report includes a set of reported coefficients; an indication of how the network node is to interpret the set of reported coefficients, wherein the indication of how the network node is to interpret the set of reported coefficients indicates the set of reported coefficients as a subset of a set of candidate reported coefficients; and an indication of a payload size of the set of the reported coefficients.

Abstract: There is provided mechanisms for transmission of reference signals. A method is performed by a terminal device. The terminal device comprises at least two physical antenna ports. The method comprises obtaining channel information. The method comprises determining, for at least one given precoder in a codebook, an uplink reference signal to physical antenna port mapping based on the channel information. The method comprises transmitting uplink reference signals in the physical antenna ports according to the determined mapping.

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: A method performed by a radio unit for handling a number of received radio signals over an array of antennas comprised in the radio unit. The radio unit transforms the number of received radio signals into a number of sequences of complex symbols. The radio unit further filters the number of sequences of complex symbols by inputting the number of sequences of complex symbols into a trained computational model comprising an alternating sequence of linear and nonlinear functions and thereby obtaining a reduced number of sequences. The radio unit further transmits the reduced number of sequences to a baseband unit over a front-haul link.

Abstract: A network node determines parameters indicating a compression function for compressing downlink channel estimates, and a decompression function. The network node transmits the parameters, receives compressed downlink channel estimates, and decompresses the compressed downlink channel estimates using the decompression function. A terminal device receives the parameters, forms the compression function, compresses downlink channel estimates using the compression function, and transmits the compressed downlink channel estimates. The compression function comprises a first function formed based on at least some of the parameters, a second function which is non-linear, and a quantizer. The first function is configured to receive input data, and to reduce a dimension of the input data. The decompression function comprises a first function configured to receive input data and provide output data in a higher dimensional space than the input data, and a second function which is non-linear.

Abstract: The disclosure includes a host operating in a communication system to provide an over-the-top (OTT) service. The host includes processing circuitry configured to initiate transmission of user data to a network node in a cellular network to a user equipment (UE). The network node is configured to receive a CSI report for a downlink channel from a wireless device and transmit the user data from the host to the UE to provide the OTT service based on the CSI report. The CSI report includes a set of reported coefficients; an indication of how the network node is to interpret the set of reported coefficients, wherein the indication of how the network node is to interpret the set of reported coefficients indicates the set of reported coefficients as a subset of a set of candidate reported coefficients; and an indication of a payload size of the set of the reported coefficients.

Abstract: In a first method, a wireless device estimates a delay profile of a channel impulse response, CIR, for a channel between a network node and the wireless device, compresses the delay profile using a compression function, and transmits the compressed delay profile. The compression function includes a first function and a quantizer. The first function is configured to receive input data and reduce a dimension of the input data. In a second method, a network node receives a compressed delay profile of CIR for a channel between a network node and a wireless device, decompresses the compressed delay profile using a decompression function, and estimates a position of the wireless device based on at least the decompressed delay profile. The decompression function includes a first function which is configured to receive input data and provide output data in a higher dimensional space than the input data.

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: There is provided mechanisms for selecting a transmission hypothesis. A method is performed by a terminal device. The method comprises receiving reference signals from at least two transmission and reception points (TRPs). The method comprises selecting, from signal quality measurements on the reference signals, a transmission 5 hypothesis from alternative transmission hypotheses pertaining to which one or more of the TRPs that is to transmit data to the terminal device. Which of the transmission hypotheses to select is affected by an adjustment term. The method comprises reporting an indication of the selected transmission hypothesis to at least one of the at least two TRPs.

Abstract: A network node determines parameters indicating a compression function for compressing downlink channel estimates, and a decompression function. The network node transmits the parameters, receives compressed downlink channel estimates, and decompresses the compressed downlink channel estimates using the decompression function. A terminal device receives the parameters, forms the compression function, compresses downlink channel estimates using the compression function, and transmits the compressed downlink channel estimates. The compression function comprises a first function formed based on at least some of the parameters, a second function which is non-linear, and a quantizer. The first function is configured to receive input data, and to reduce a dimension of the input data. The decompression function comprises a first function configured to receive input data and provide output data in a higher dimensional space than the input data, and a second function which is non-linear.

Abstract: There is provided mechanisms for transmission of reference signals. A method is performed by a terminal device. The terminal device comprises at least two physical antenna ports. The method comprises obtaining channel information. The method comprises determining, for at least one given precoder in a codebook, an uplink reference signal to physical antenna port mapping based on the channel information. The method comprises transmitting uplink reference signals in the physical antenna ports according to the determined mapping.

Abstract: A network node (501) determines parameters (503) indicating a compression function for compressing downlink channel estimates, and a decompression function. The network node transmits the parameters, receives compressed downlink channel estimates (504), and decompresses the compressed downlink channel estimates using the decompression function. A terminal device (502) receives the parameters, forms the compression function, compresses downlink channel estimates using the compression function, and transmits the compressed downlink channel estimates. The compression function comprises a first function formed based on at least some of the parameters, a second function which is non-linear, and a quantizer. The first function is configured to receive input data, and to reduce a dimension of the input data. The decompression function comprises a first function configured to receive input data and provide output data in a higher dimensional space than the input data, and a second function which is non-linear.

Abstract: A method performed by a radio unit for handling a number of received radio signals over an array of antennas comprised in the radio unit. The radio unit transforms the number of received radio signals into a number of sequences of complex symbols. The radio unit further filters the number of sequences of complex symbols by inputting the number of sequences of complex symbols into a trained computational model comprising an alternating sequence of linear and nonlinear functions and thereby obtaining a reduced number of sequences. The radio unit further transmits the reduced number of sequences to a baseband unit over a front-haul link.