Abstract: A method in a network node for Multiple Input Multiple Output (MIMO) is provided. The method comprises: obtaining a precoding matrix indicator (PMI) for a first codebook for use in a Single User Multiple Input Multiple Output (SU-MIMO) transmission; determining a precoding matrix for a second codebook, based on the obtained precoding matrix indicator; and selecting the determined precoding matrix for the second codebook in response to determining that an User Equipment (UE) is scheduled for a Multi-User (MU)-MIMO transmission. A network node for performing this method is also provided.

Abstract: A method, base station and user equipment are disclosed. A base station configured to communicate with a plurality of user equipments is provided. The base station includes processing circuitry configured to: track a downlink signal subspace for each UE of the plurality of UEs, and determine a Multi-User Multiple-Input Multiple-Output, MU-MIMO, precoders based on the downlink signal subspace for each UE of the plurality of UEs. The MU-MIMO precoders are configured to at least in part suppress intra-cell MU-MIMO interference.

Abstract: A network node, wireless device and methods for co-phasing for beamforming using co-phasing matrices for wireless communications are provided. In one example, a network node for co-phasing in beamforming for transmissions is provided. The network node includes processing circuitry including a processor and a memory where the memory contains instructions executable by the processor to configure the network node to: obtain co-phasing information associated with a wireless device, generate at least two co-phasing matrices based on the co-phasing information, and apply the at least two co-phasing matrices to at least two resource structures.

Abstract: Apparatuses and methods for port-to-antenna mapping in a virtualized Active Antenna System (AAS) are provided. In one embodiment, a method for a radio node includes determining a source codebook associated with at least one antenna port; determining a target codebook associated with at least one physical antenna; and determining a port-to-antenna mapping matrix based at least in part on the determined source codebook and the determined target codebook.

Abstract: Apparatuses and methods are disclosed for Channel State Information Reference Signal (CSI-RS) resource mapping. According to one embodiment, a method in a network node includes allocating at least one resource for CSI Interference Measurement (CSI-IM) within a predetermined IM region of a Resource Block (RB) of the cell, the predetermined IM region encompassing a plurality of resources of the RB of the cell, the allocated at least one resource being selected from among the plurality of resources of the IM region to reduce a likelihood of overlap with at least one resource allocated for CSI-IM in a neighboring cell, the predetermined IM region at least partially overlapping with a respective predetermined IM region of a RB of the neighboring cell, and the predetermined IM region of the cell not overlapping resources allocated for Non-Zero Power Channel State Information Reference Signal (NZP CSI-RS) of the neighboring cell.

Abstract: A method in a network node for Multiple Input Multiple Output (MIMO) is provided. The method comprises: obtaining a precoding matrix indicator (PMI) for a first codebook for use in a Single User Multiple Input Multiple Output (SU-MIMO) transmission; determining a precoding matrix for a second codebook, based on the obtained precoding matrix indicator; and selecting the determined precoding matrix for the second codebook in response to determining that an User Equipment (UE) is scheduled for a Multi-User (MU)-MIMO transmission. A network node for performing this method is also provided.

Abstract: Systems and methods are disclosed herein that related to determining and using a codebook in a virtualized Active Antenna System (AAS). In some embodiments, a first radio node that is configured to communicate with a second radio node comprises a radio interface and processing circuitry configured to transform a first codebook that is in a non-virtualized antenna domain to a second codebook that is in a virtualized antenna domain based on a port to antenna mapping matrix used to transform a signal from the virtualized antenna domain to the non-virtualized antenna domain prior to transmission of the signal in a corresponding virtualized cell or sector. The processing circuitry is further configured to receive a transmit signal from the second radio node to thereby provide a received signal and perform Precoding Matrix Indication (PMI) estimation based on the received signal using the second codebook in the virtualized antenna domain.

Abstract: Systems and methods related to optimized selection, or determination of, Hybrid Automatic Repeat Request (HARQ) feedback modes for downlink transmissions by considering Time Division Duplexing (TDD) uplink/downlink (UL/DL) configuration, transmission mode, cell load, and/or traffic type are disclosed. In this manner, performance can be improved.

Abstract: Systems and methods for estimating Signal-to-Noise Ratio (SNR) for Multi-User Multiple-Input and Multiple-Output (MU-MIMO) based on channel orthogonality. In some embodiments, a method performed by a radio access node includes obtaining a SU-MIMO signal quality measurement for at least a first user and an additional user; obtaining an indication of orthogonality between a channel of the first user and a channel of the additional user; and estimating a MU-MIMO signal quality measurement for the first user as if the first user and the additional user are paired with each other for a potential MU-MIMO transmission based on the SU-MIMO signal quality measurements and the indication of orthogonality. In this way, a computational complexity for the SINR estimation of MU-MIMO users can be greatly reduced. This may enable a large number of user pairing alternatives to be evaluated in practical wireless systems to achieve improved MU-MIMO performance.

Abstract: Methods, apparatuses and a user equipment for performing a Hybrid Automatic Repeat Request (HARQ) transmission in a downlink from a base station to at least one user equipment are provided. An exemplary method comprises receiving a HARQ feedback to a HARQ transmission performed with respect to a transport block. The method further comprises determining whether the HARQ feedback is an ambiguous HARQ feedback with respect to a negative acknowledgement or a discontinuous transmission. The method additionally comprises setting (S206) the ambiguous HARQ feedback as the negative acknowledgement or the discontinuous transmission based on the number of HARQ transmissions having been performed and the corresponding received HARQ feedbacks within a target number of HARQ transmissions counting from a first HARQ transmission. With the methods and apparatuses, the ambiguity of the HARQ feedback can be overcome and communication efficiency may be improved.

Abstract: A method performed by a wireless transmitter determining a transport block size (TBS) is provided. The method includes determining a TBS using a general function of a number of physical resource blocks (PRBs) to be granted (N_PRB), a number of resource elements (REs) per PRB (N_RE{circumflex over (?)}(DL,PRB)), a number of layers per transport block (?), a number of bits per modulation (Q_m), and a coding rate determined by a modulation coding scheme (MCS) (R), allocating a transport block of the determined TBS and transmitting the transport block to a wireless receiver. Apparatuses for implementing the method are also provide.

Abstract: Systems and methods for selectively enabling antenna selection at a wireless device for uplink sounding reference signal transmission in a Time Division Duplexing (TDD) wireless communication system are disclosed. In some embodiments, a method of operation of a network node comprises making a determination as to whether to enable or disable antenna selection at a wireless device for transmission of uplink sounding reference signals based on: an estimated speed of movement of the wireless device; both the estimated speed and a Signal to Interference plus Noise Ratio (SINR) for one or more downlink channels to the wireless device; or the estimated speed, the SINR for the one or more downlink channels, and a rank used for downlink transmission to the wireless device. The method further comprises sending, to the wireless device, an indication that indicates whether the wireless device is to enable or disable antenna selection.

Abstract: The present disclosure relates to a method used in a BS for scheduling a UE, and an associated BS. The method includes: determining four sets of PUCCH format 1b with channel selection resources, which include a part of CCE-mapped dynamic HARQ feedback resources reserved for the UE transmitting HARQ feedback to the BS by using PUCCH format 1a/1b, each set including two PUCCH format 1b with channel selection resources; selecting one of the four sets of PUCCH format 1b with channel selection resources as candidate resources, which are available for the UE transmitting HARQ feedback to the BS by using PUCCH format 1b with channel selection; and transmitting to the UE an indication indicating the selected one of the four sets of PUCCH format 1b with channel selection resources. The present disclosure also relates to a method used in a UE for transmitting HARQ feedback to a BS by using PUCCH format 1b with channel selection, and an associated UE.

Abstract: Systems and methods related to optimized selection, or determination of, Hybrid Automatic Repeat Request (HARQ) feedback modes for downlink transmissions by considering Time Division Duplexing (TDD) uplink/downlink (UL/DL) configuration, transmission mode, cell load, and/or traffic type are disclosed. In this manner, performance can be improved.

Abstract: Methods, apparatuses and a user equipment for performing a Hybrid Automatic Repeat Request (HARQ) transmission in a downlink from a base station to at least one user equipment are provided. An exemplary method comprises receiving a HARQ feedback to a HARQ transmission performed with respect to a transport block. The method further comprises determining whether the HARQ feedback is an ambiguous HARQ feedback with respect to a negative acknowledgement or a discontinuous transmission. The method additionally comprises setting (S206) the ambiguous HARQ feedback as the negative acknowledgement or the discontinuous transmission based on the number of HARQ transmissions having been performed and the corresponding received HARQ feedbacks within a target number of HARQ transmissions counting from a first HARQ transmission. With the methods and apparatuses, the ambiguity of the HARQ feedback can be overcome and communication efficiency may be improved.

Abstract: Methods, apparatuses and a user equipment for performing a Hybrid Automatic Repeat Request (HARQ) transmission in a downlink from a base station to at least one user equipment are provided. An exemplary method comprises receiving a HARQ feedback to a HARQ transmission performed with respect to a transport block. The method further comprises determining whether the HARQ feedback is an ambiguous HARQ feedback with respect to a negative acknowledgement or a discontinuous transmission. The method additionally comprises setting (S206) the ambiguous HARQ feedback as the negative acknowledgement or the discontinuous transmission based on the number of HARQ transmissions having been performed and the corresponding received HARQ feedbacks within a target number of HARQ transmissions counting from a first HARQ transmission. With the methods and apparatuses, the ambiguity of the HARQ feedback can be overcome and communication efficiency may be improved.

Abstract: The embodiments disclose a method and apparatus for performing DL MU-MIMO transmission in a radio communication network enabling MU-MIMO. The method comprises: pairing a UE with one or more other UEs for DL MU-MIMO transmission in the radio communication network; scheduling through a control channel at least one real layer and at least one virtual layer to the UE, wherein each of the at least one virtual layer is a real layer scheduled for at least one of the one or more other UEs; and performing DL transmission to the UE and the one or more other UEs on a transport channel, wherein only the at least one real layer is used for DL transmission to the UE, and each of the at least one virtual layer is used for DL transmission to at least one of the one or more other UEs.

Abstract: One of the embodiments of the present invention relates to a method for rank adaptation at a base station. The method comprises performing, during a rank sounding time interval, data transmission for a user equipment by using a sounding rank. The sounding rank is different from a transmission rank that is used in a transmission time interval immediately prior to the rank sounding time interval. The method further comprises determining whether spectrum efficiency for the user equipment under the condition of using the sounding rank is better than spectrum efficiency under the condition of using the transmission rank; and adjusting, in response to a positive result obtained from the determining step, the transmission rank to the sounding rank so as to be used during a transmission time interval immediately next to the rank sounding time interval. The present invention also relates to corresponding base station device.

Abstract: The present disclosure relates to a method used in a BS for scheduling a UE, and an associated BS. The method includes: determining four sets of PUCCH format 1b with channel selection resources, which include a part of CCE-mapped dynamic HARQ feedback resources reserved for the UE transmitting HARQ feedback to the BS by using PUCCH format 1a/1b, each set including two PUCCH format 1b with channel selection resources; selecting one of the four sets of PUCCH format 1b with channel selection resources as candidate resources, which are available for the UE transmitting HARQ feedback to the BS by using PUCCH format 1b with channel selection; and transmitting to the UE an indication indicating the selected one of the four sets of PUCCH format 1b with channel selection resources. The present disclosure also relates to a method used in a UE for transmitting HARQ feedback to a BS by using PUCCH format 1b with channel selection, and an associated UE.

Abstract: Methods, apparatuses and a user equipment for performing a Hybrid Automatic Repeat Request (HARQ) transmission in a downlink from a base station to at least one user equipment are provided. An exemplary method comprises receiving a HARQ feedback to a HARQ transmission performed with respect to a transport block. The method further comprises determining whether the HARQ feedback is an ambiguous HARQ feedback with respect to a negative acknowledgement or a discontinuous transmission. The method additionally comprises setting (S206) the ambiguous HARQ feedback as the negative acknowledgement or the discontinuous transmission based on the number of HARQ transmissions having been performed and the corresponding received HARQ feedbacks within a target number of HARQ transmissions counting from a first HARQ transmission. With the methods and apparatuses, the ambiguity of the HARQ feedback can be overcome and communication efficiency may be improved.