Abstract: Systems and methods for port selection in a wireless communication system are disclosed. In embodiment, a method performed by a radio access network (RAN) node for mapping Sounding Reference Signal (SRS) ports to transmission layers comprises obtaining a channel matrix, H, for one subcarrier or a group of subcarriers for a particular User Equipment (UE) and transforming the channel matrix, H, using a Singular Value Decomposition (SVD) of the channel matrix to thereby provide a transformed channel matrix. The method further comprises computing beamforming weights using the transformed channel matrix. Embodiments of a RAN node are also disclosed.

Abstract: Systems and methods are disclosed for port selection for a wireless communication system. In one embodiment, a method performed by a Radio Access Network (RAN) node comprises dividing a channel matrix of one subcarrier of a Multiple-Input-Multiple-Output (MIMO) channel between an antenna array of the RAN node and a particular User Equipment (UE) into sub-matrices. The method further comprises forming a re-ordered channel matrix as a concatenation of the sub-matrices and forming a port-sorting matrix based on eigen vector matrices and eigen value matrices obtained via Eigen Value Decompositions (EVDs) performed on channel covariance matrices for the sub-matrices. The method further comprises applying the port-sorting matrix to the re-ordered channel matrix, re-ordering column vectors in the port-sorted channel matrix based on eigen values obtained from the EVDs, and applying grouping of the re-ordered, port-sorted channel matrix and port sorting accordingly to obtain a final port-sorted channel matrix.

Abstract: A method, system and apparatus are disclosed. According to one or more embodiments, a network node is provided. The network node includes processing circuitry configured to determine a precoder using one of wideband channel state information and frequency-dependent channel state information based on at least one mobility estimate, and cause transmission to a wireless device using the determined precoder.

Abstract: A method performed by a network node is provided. The network node calculates a first Information Carrying Capacity (ICC) associated with a first layer. The first ICC is calculated based on beam weights calculated for the first layer, and an established channel estimate of the first layer. The first layer is selected to a set of layers. The network node performs actions iteratively at least one time for layer selection, adds a subsequent layer, adapts the calculated beam weights to be used as subsequent beam weights for a subsequent layer, calculates a subsequent ICC for the subsequent layer, decides whether to select the added subsequent layer to the set of layers and rejecting the subsequent layer when the sum of the ICCs of the layers in the set of layers and the subsequent ICC is lower than the sum of ICCs of the layers in the set of layers.

Abstract: A method is disclosed for spatial resource selection from a plurality of spatial resources. The method comprises, for each of least one spatial resource of the plurality of spatial resources, determining, for each of multiple time instances, a quality state for the spatial resource, based on reference signals received on the spatial resource, and filtering the quality states, to determine a filtered quality state value for the spatial resource. The method further comprises determining whether the spatial resource is to be considered for spatial resource selection based on the filtered quality state value. The spatial resources may be beams of a beam-forming application, or antennas of a multi-antenna arrangement, or multiple-input multiple-output (MIMO) streams, for example. The reference signals may comprise one or more of uplink reference signals, sounding reference signals, demodulation reference signals, and phase tracking reference signals. Corresponding apparatus, network node (e.g.

Abstract: There is provided mechanisms for radio link adaptation at a transmit and receive point. A method is performed by a network node. The method includes obtaining LLR values for a block of codewords. The LLR values are output from an information decoder decoding the block of codewords. The block of codewords has been communicated over a radio link between the transmit and receive point and a terminal device. The method includes performing radio link adaptation of the radio link depending on the LLR values by selecting radio link adaptation parameter values. Which radio link adaptation parameter values to select depends on the LLR values.

Abstract: A method performed by a communication node and an apparatus for operating the method are proposed. The method includes obtaining matched filter channel estimation associated with a user equipment (UE); obtaining first Timing Advance (TA) compensated channel estimation; obtaining first noise suppressed channel estimation; and obtaining first TA estimation associated with the UE based on the first noise suppressed channel estimation.

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 in a first node (610, 615) is disclosed. The method comprises determining (704) a time resource over which the first node transmits a signal to a second node (610, 615). The method comprises signaling (708), to at least one of the second node or a third node (610, 615), information about one or more transient time parameters associated with the time resource, wherein the one or more transient time parameters are used by the first node for transmitting the signal to the second node during the time resource. The method comprises adapting (712) a transmitter configuration of the first node for transmitting the signal to the second node based on one of the one or more transient time parameters.

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: Embodiments of a method in a base station for precoding a downlink transmission are disclosed. In some embodiments, the method comprises obtaining, for a time instant k, an estimate of a channel matrix for a wireless channel for a downlink from the base station to a wireless device and projecting the estimate of the channel matrix onto one or more sets of spatial orthonormal functions, thereby obtaining respective sets of coefficients. The method further comprises, for each set of spatial orthonormal functions, filtering the set of coefficients for the time instant k based on a filtering parameter that is specific to a downlink channel to be transmitted. The method further comprises generating beamforming weights using the filtered set of coefficients for at least one of the sets of spatial orthonormal functions, and precoding the downlink channel using the beamforming weights.

Abstract: There is provided a method for managing transmission of a Cell-specific Reference Signal, CRS, comprising a plurality of reference symbols to User Equipment, UE, in a wireless communication system operating at least one cell or sector. The method comprises identifying a UE for which a beamformed transmission of data is scheduled during a transmission time interval, and enabling, during the transmission time interval, beamformed transmission of at least part of the reference symbols of the CRS for targeting the identified UE.

Abstract: A method and a first network node (800) serving a first cell (800A) in a wireless network, for enabling reduction of interference in a second cell (800B) caused by transmission of reference signals in the first cell (800A). The first network node (800) transmits (8:1) scheduling blocks with said reference signals, using a time offset relative transmission of scheduling blocks in the second cell. A timing advance value is determined (8:3) for a wireless device (802) and the wireless device (802) instructed (8:4) to apply said timing advance value for uplink transmissions. The timing advance value was determined such that uplink symbols transmitted from the wireless device (802) are aligned with uplink symbols received at a second network node (804) of the second cell (804A).

Abstract: The present embodiments disclose a network node (400); a method thereof; a user equipment (700) and a method thereof. The method performed by the network node (400) comprises: selecting (301) a cell-specific RS process; selecting (302) a beam scan pattern; selecting (303) 5 a UE (799); transmitting (304) a cell specific RS associated to the cell-specific RS process, to the selected UE (700); configuring (305) the UE with the selected cell-specific RS process and receiving (306) a beam report from the UE (700).

Abstract: A scheduling function node (SF) uses the beams available for each WCD to avoid scheduling a transmission that would imply that interference between WCDs is created. In the simplest form such a scheme could be described as follows: (1) avoid scheduling transmission in directions that coincide between WCDs (here, a direction would typically be represented by both azimuth and elevation angles) and (2) when the available beam directions do not allow interference avoidance, accounting for this fact and exploiting other types of orthogonality in the scheduling of time-frequency resources.

Abstract: A method and a network node (700) serving a first cell in a wireless network, for reducing interference in a second cell caused by transmission of reference signals in the first cell. The network node (700) transmits (7:2) in the first cell a scheduling block where a number of said reference signals are located in predefined resource element positions in the scheduling block, using a time offset relative transmission of a scheduling block in the second cell. Thereby, the impact of interference from a reference signal from one network node will be distributed over several resource elements in the other network node so that the impact in each resource element is reduced, as compared to when all interference from the reference signal hits one single resource element when no time offset is used.

Abstract: It is presented a method for controlling cyclic shift for demodulation reference symbols for uplink communication in a cellular communication network. The method is performed in a network node and comprises the steps of: determining a first cyclic shift parameter for demodulation reference symbols based on a current subframe index; generating a control message comprising the first cyclic shift parameter; and transmitting the control message to a wireless device of the cellular communication network. Corresponding network nodes, computer program and computer program product are also presented.

Abstract: A base station that implements an improved link adaptation process that takes into account the fact that a certain reference signal (e.g., CSI-RS) may be seen as interference by certain wireless communication devices (WCDs). Accordingly, when the base station schedules a data transmission for the WCD to occur in a particular TTI and the base station is scheduled to transmit the CSI-RS during the same TTI, the base station will tend to select a more robust MCS for the data transmission to the WCD to counter effect the possible interference caused by the CSI-RS.

Abstract: The teachings relate to a method 100 performed in a network node 2 for determining a link adaptation parameter, SINRLA,i, for a wireless device 3. The network node 2 supporting a multi-antenna transmission mode comprising spatial multiplexing layers for transmission of data on a channel between the wireless device 3 and the network node 2. The method 100 comprises: determining 110 a channel covariance matrix HHH for the channel, wherein H is the channel matrix for the channel; approximating 120 a post-equalizer signal to interference plus noise ratio SINRapprox., for a spatial multiplexing layer i using the channel covariance matrix HHH; determining 130 an offset SINRoffset, i to be the difference between a received signal to interference plus noise ratio SINRreceived and the approximated post-equalizer signal to interference plus noise ration SINRapprox.

Abstract: A method in a base station (110) for providing an estimate of interference and noise power of an uplink resource block. The base station (110) is comprised in a cellular communications network (100). The base station (110) receives (401, 901) on multiple antenna elements (112a-c) of a receiver antenna (112) a signal comprising interference and noise. The base station (110) calculates (402, 902) an interference and noise covariance matrix for the resource block based on the received signal. The base station (110) then calculates (903, 403) the estimate based on the calculated interference and noise covariance matrix, the number of the multiple antenna elements (112a-c) of the receiver antenna (112) and a channel covariance matrix for a virtual user equipment. The provided estimate enables an interference and noise measure when Interference Rejection Combining (!RC) is applied in the uplink.