Abstract: A method and a device for determining parameters of a precoder in a wireless communication system are disclosed. According to one aspect, a method includes selecting a subset of beams corresponding to a plurality of orthogonal beams; obtaining power levels of the selected subset of beams for generating a first factor of the precoder and obtaining phases of the selected subset of beams for generating a second factor, wherein the first factor and the second factor are part of the parameters of the precoder.

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: Some embodiments provide a method in a wireless device for reporting channel state information, CSI, for a CSI process. The CSI process corresponds to a reference signal resource and an interference measurement resource. According to the method, the wireless device obtains an adjustment value associated with the CSI process. The wireless device estimates an effective channel based on one or more reference signals received in the reference signal resource, and applies the adjustment value to the estimated effective channel, thereby obtaining an adjusted effective channel. Furthermore, the wireless device determines channel state information based on the adjusted effective channel, and on interference estimated based on the interference measurement resource. Finally, the channel state information is transmitted to a network node.

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: Some embodiments provide a method in a wireless device for reporting channel state information, CSI, for a CSI process. The CSI process corresponds to a reference signal resource and an interference measurement resource. According to the method, the wireless device obtains an adjustment value associated with the CSI process. The wireless device estimates an effective channel based on one or more reference signals received in the reference signal resource, and applies the adjustment value to the estimated effective channel, thereby obtaining an adjusted effective channel. Furthermore, the wireless device determines channel state information based on the adjusted effective channel, and on interference estimated based on the interference measurement resource. Finally, the channel state information is transmitted to a network node.

Abstract: The invention relates to methods and arrangements in a transmitting node for enabling a receiving node to perform measurements on interference caused by transmissions from at least one transmission point controlled by the transmitting node on receptions at the receiving node. The transmitting and receiving nodes are comprised in a wireless communications system. The transmitting node determines an interference measurement resource, IMR, for the receiving node. The receiving node is expected to measure interference on the IMR. The transmitting node then transmits at least one interfering signal on the IMR. The at least one interfering signal is not expected to be decoded or coherently measured upon by any node served by the transmitting node.

Abstract: The invention relates to a method and an arrangement in a transmitting node (560) for enabling a receiving node (540) to perform measurements on interference caused by transmissions from at least one transmission point (510, 520, 530) controlled by the transmitting node (560) on receptions at the receiving node (540). The transmitting and receiving nodes (560, 540) are comprised in a wireless communications system (500, 600, 700). The transmitting node determines (910) an interference measurement resource, IMR, comprising a set of Time-Frequency Resource Elements, TFREs, upon which the transmitting node is expected to transmit interference. The transmitting node then transmits (930) at least one interfering signal on said IMR as said interference.

Abstract: A method performed by a network node (110) for estimating a convergence time of interference processing in a user equipment, UE (121), served by the network node (110) in a radio communications network (100) is provided. The network node has at least one Channel State Information, CSI, process configured for the UE. The network node receives, from the UE, at least one first CSI report based on signals transmitted on interference measurement resources of a first CSI process of the UE, wherein the first CSI process is in a first interference state. The network node then switches the first CSI process from the first interference state to a second interference state. After the switch, the network node receives, from the UE, at least one second CSI report based on signals transmitted on the interference measurement resources of the first CSI process of the UE, wherein the first CSI process is in the second interference state.

Abstract: Frequency-selective phase shifts are applied to signals transmitted from multiple transmission points involved in a coordinated (joint) transmission to a given UE. An eNodeB or other network node controlling the joint transmission artificially induces frequency selectivity between signals received by the UE in joint transmission from different transmission points, so as to ensure an even balance between constructive and destructive combination over frequency. By applying frequency-selective phase shifts (e.g., pseudo-random phase shifts) to the different transmission points that perform joint transmission, the signals from the different transmission points are forced to combine at the UE in a non-coherent manner. As a result, uncertainty in how the signals combine is drastically reduced, since it can be expected that the signals will always combine incoherently. The reduced uncertainty translates to reduced back-off offset in the link adaptation, and thus in an increased throughput.

Abstract: A system and method for providing an eNodeB with the flexibility to configure a Channel State Information (CSI) report to match a specific Coordinated Multipoint (CoMP) transmission hypothesis, which is a candidate for a downlink transmission to a User Equipment (UE) is disclosed. A UE receives, from the eNodeB, a configuration message that specifies a CSI report. The CSI report is specified by a particular interference hypothesis and a particular desired signal hypothesis corresponding to data transmission over at least one effective channel characterized by a specific reference signal. The UE estimates interference according to the interference hypothesis, and/or estimates at least one effective channel by performing measurements on the specific reference signal, and determines a CSI report based on the interference estimation and on the estimated effective channel. The UE also transmits the CSI report to the eNodeB.

Abstract: The present disclosure relates to a method performed in a network node with two or more transmission states for dynamically managing outer loop link adaptation instances for a wireless device. The method includes monitoring one or more variables, where each variable is either associated with an outer loop link adaptation instance or with a transmission state; and adapting the number of outer loop link adaptation instances based on the monitored one or more variables. The disclosure also relates to corresponding devices.

Abstract: It is presented a method for mapping one or more codewords to antennas of the same cell under control of a radio base station of a cellular communication system, wherein the antennas are distributed over at least two different sites. The method is performed in a radio base station and comprises: determining a distribution matrix such that each one of the one or more codewords is substantially only mapped to at least two antennas located at only one site; and applying the distribution matrix to the one or more codewords. Corresponding radio base stations, computer program and computer program product are also presented.

Abstract: A system and method for providing an eNodeB with the flexibility to configure a Channel State Information (CSI) report to match a specific Coordinated Multipoint (CoMP) transmission hypothesis, which is a candidate for a downlink transmission to a User Equipment (UE) is disclosed. A UE receives, from the eNodeB, a configuration message that specifies a CSI report. The CSI report is specified by a particular interference hypothesis and a particular desired signal hypothesis corresponding to data transmission over at least one effective channel characterized by a specific reference signal. The UE estimates interference according to the interference hypothesis, and/or estimates at least one effective channel by performing measurements on the specific reference signal, and determines a CSI report based on the interference estimation and on the estimated effective channel. The UE also transmits the CSI report to the eNodeB.

Abstract: Some example embodiments presented herein are directed towards an eNodeB, and corresponding method therein, for establishing beamforming for downlink communications in a multiple antenna system. The eNodeB may transmit a plurality of reference signals, where each reference signal is beamformed into a distinct direction with in at least one correlated domain (e.g., an elevation and/or azimuth domain). The eNodeB may generate beamformed downlink communications for antenna elements and/or subelements based on received signal quality assessments of the plurality of reference signals. Some example embodiments may be directed towards a user equipment, and corresponding methods therein, for establishing beamforming for downlink communications. The user equipment may receive the plurality of reference signals and provide signal assessments of the reference signals based on measurements performed by the user equipment.

Abstract: According to some embodiments, a method of adapting reference signals of a wireless network comprises establishing a first wireless connection with a first user equipment. The first wireless connection is associated with one or more references signals and each of the one or more reference signals is associated with one or more antenna ports. The method further comprises mapping one of the one or more reference signals associated with one or more antenna ports to at least two antenna port reference signal resources (APRSR) for the first user equipment, wherein the APRSR comprises a pair of consecutive time-frequency resource elements of a radio subframe of the first wireless connection.

Abstract: Some embodiments provide a method in a wireless device for reporting channel state information, CSI, for a CSI process. The CSI process corresponds to a reference signal resource and an interference measurement resource. According to the method, the wireless device obtains an adjustment value associated with the CSI process. The wireless device estimates an effective channel based on one or more reference signals received in the reference signal resource, and applies the adjustment value to the estimated effective channel, thereby obtaining an adjusted effective channel. Furthermore, the wireless device determines channel state information based on the adjusted effective channel, and on interference estimated based on the interference measurement resource. Finally, the channel state information is transmitted to a network node.

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: Example embodiments presented herein are directed towards an eNodeB, and method therein, for generating downlink communications in a multiple antenna system. The method comprises transmitting, to a number of user equipments, a plurality of reference signals, where each signal is beamformed in a distinct direction within at least one correlated domain (e.g., elevation and/or azimuth). The eNodeB receives at least one CSI report from a specific user equipment and determines a primary reference signal based on, for example, the at least one CSI report. The eNodeB may thereafter generate downlink communication signals for antenna element(s) and/or subelements of the multiple antenna system. The downlink communication signals are beamformed into a transmitting direction that aligns most closely with a beamforming direction of the at least one primary reference signal, as compared to any other beamforming direction of the reference signals.

Abstract: Some embodiments provide a method in a wireless device for reporting channel state information, CSI, for a CSI process. The CSI process corresponds to a reference signal resource and an interference measurement resource. According to the method, the wireless device obtains an adjustment value associated with the CSI process. The wireless device estimates an effective channel based on one or more reference signals received in the reference signal resource, and applies the adjustment value to the estimated effective channel, thereby obtaining an adjusted effective channel. Furthermore, the wireless device determines channel state information based on the adjusted effective channel, and on interference estimated based on the interference measurement resource. Finally, the channel state information is transmitted to a network node.

Abstract: A system and method for improving the link adaptation in a wireless communication system is disclosed. User Equipment (UE) forms an interference hypothesis by amending a measured interference and noise by artificially injecting, to the measured interference and noise, interference corresponding to at least one emulated interfering isotropic signal that is virtually transmitted over an associated estimated effective channel. The UE further determines at least one channel state information (CSI) report based on the interference hypothesis, and transmits the CSI report to the network.