Abstract: A method may be provided to operate a first base station in a Radio Access Network including the first base station and a second base station. According to this method, a Reference Signal Received Power (RSRP) measurement list, a Coordinated Multipoint (CoMP) hypothesis, and a Benefit Metric may be communicated between the first and second base stations.

Abstract: The present invention provides a unified, rank independent mapping between antenna ports and group/code pairs. Each antenna port is uniquely associated with one code division multiplexing (CDM) group and one orthogonal cover code (OCC). The mapping between antenna ports and group/code pairs is chosen such that, for a given antenna port, the CDM group and OCC will be the same for every transmission rank.

Abstract: Techniques and apparatus for selectively switching among two or more possible reference signal densities are disclosed. An example method comprises obtaining (110) one or more reference signal conditions that governs the density of the reference signal format to be transmitted by a wireless communication device in conjunction with data transmissions, where the one or more reference signal conditions are defined in advance of any scheduling of those data transmissions. The example method further comprises evaluating (120) the one or more reference signal conditions and selecting (130) a density of a reference signal format, from two or more possible densities, based on the outcome of the evaluation. In embodiments where the node that carries out the evaluation is the transmitting node, the method further comprises transmitting (140) one or more reference signals in conjunction with one or more data transmissions, in accordance with the selected reference signal density.

Abstract: Techniques are disclosed for signaling a pattern of cyclic shifts and orthogonal cover codes for use by a wireless device in multi-layer transmissions. In one example method, a signal includes B bits for identifying a reference signal is received, wherein each of several available reference signals is defined by a cyclic shift and an orthogonal cover code. The B bits are used to identify the cyclic shift and orthogonal cover code according to pre-determined tables that map each value of the B bits to a pattern of cyclic shift and orthogonal cover code combinations for a multi-layer transmission scheme. The patterns for the multi-layer transmission scheme include first and second patterns based on the same cyclic shifts, but where some, but not all, of the cyclic shifts in the first pattern are associated with the same corresponding orthogonal cover codes in the second pattern.

Abstract: The invention relates to devices and methods for signalling control information associated with transmission of data over a wireless channel. A second communication device receives (S2) data from a first communication device, wherein the data comprises an indication of recommended precoders and a recommendation of a first transmission rank to possibly use during transmission. The second communication device determines (S4) a second transmission rank to use for transmitting data, and transmits (S6) a confirmation message to the first communication device. The confirmation message comprises a confirmation that transmission of data from the second communication device is using at least parts of each recommended precoder associated with a frequency resource that falls within the transmission of data and an indicator of the second transmission rank to use.

Abstract: Techniques are disclosed for signaling a pattern of cyclic shifts and orthogonal cover codes for use by a wireless device in multi-layer transmissions. In one example method, a signal includes B bits for identifying a reference signal is received, wherein each of several available reference signals is defined by a cyclic shift and an orthogonal cover code. The B bits are used to identify the cyclic shift and orthogonal cover code according to pre-determined tables that map each value of the B bits to a pattern of cyclic shift and orthogonal cover code combinations for a multi-layer transmission scheme. The patterns for the multi-layer transmission scheme include first and second patterns based on the same cyclic shifts, but where some, but not all, of the cyclic shifts in the first pattern are associated with the same corresponding orthogonal cover codes in the second pattern.

Abstract: Method and apparatus for enabling accurate link quality estimation of a wireless link between a sending node and a receiving node. When the sending node receives link state reports from the receiving node, it estimates the current state of the wireless link. The sending node also determines a measurement adjusting parameter if the link state reports are deemed inaccurate in relation to the estimated link state, based on a deviation between the received link state reports and the estimated actual link state. The sending node then sends the determined measurement adjusting parameter to the receiving node, and the receiving node provides a link state report based on signal measurements adjusted by the measurement adjusting parameter. The adjusted link state report can then be used for link adaptation of the wireless link and/or for packet scheduling decisions.

Abstract: A high-power point and one or more low-power points transmit signals associated with the same cell-identifier in a heterogeneous cell deployment. Coverage areas corresponding to the low-power points fall at least partly within the coverage area for the high-power point, so that mobile stations within range of a low-power point are also within range of the high-power point. Channel-state-information reference symbols, CSI-RS, are transmitted using different CSI-RS resources on different transmission points within the cell, while configuration of CSI-RS measurement resources is conducted on a UE-specific basis. The choice of measurement resources to be used is determined by the network, based on the properties of the channels from the transmission points to the UE. As the UE moves around within the cell, the network tracks the channel properties and reconfigures the CSI-RS resources measured by the UE, to correspond to the resource of the closest transmission point or points.

Abstract: According to some embodiments, a wireless device receives (1020) a discovery burst from a network node (115). The same discovery burst includes multiple signals within at least one subframe, each of the multiple signals having one or more associated measurement functions. At least one of the multiple signals is received with multiple repetitions within the same discovery burst and two or more repetitions of the same type of signal can be combined by the wireless device. The wireless device performs (1024) at least one radio measurement based at least in part on a particular one of the signals of the discovery burst. The performed at least one radio measurement corresponds to a measurement function associated with the particular signal of the discovery burst.

Abstract: A method implemented by a wireless terminal of reporting channel state information to a wireless communication network is disclosed. The wireless terminal receives reference symbols on a set of channel state information reference symbol (CSI-RS) resources, and determines a common transmission rank for the set of CSI-RS resources, based on the reference symbols received on a subset of those CSI-RS resources. The terminal then generates CSI feedback as a function of the common transmission rank, and transmits the CSI feedback to the communication network. The CSI feedback may include the common transmission rank itself, or may include different transmission ranks for different CSI-RS resources each determined as a function of the common transmission rank. A complementary method in which a network node uses such a CSI feedback to perform rank adaptation for the set of CSI-RS resources is also disclosed.

Abstract: An objective problem of the invention is to provide a mechanism for improving the performance of a radio access network. According to a first aspect of the present invention, the object is achieved by a method in a first node for adapting a multi-antenna transmission to a second node over an effective channel. The first node and the second node are comprised in a wireless communication system. The method comprises the steps of obtaining at least one symbol stream and determining a precoding matrix having a block diagonal structure. The method comprises the further steps of precoding the at least one symbol stream with the determined precoding matrix, and transmitting the at least one precoded symbol stream over the effective channel to the second node.

Abstract: Techniques for collecting channel-state-information (CSI) feedback in a wireless network that comprises a plurality of geographically separated transmission points include methods in which a set of CSI reference symbol (CSI-RS) resources are identified, which correspond to the union of CSI-RS resources used by multiple transmission points in the primary transmission point's coverage area. A mobile station is configured to measure CSI-RS on a subset of the CSI-RS resources, the subset corresponding to CSI-RS resources used by a subset of the transmission points. The mobile station is also configured to assume that no downlink data will be transmitted in the remaining portion of the set of CSI-RS resources. CSI feedback is then received from the mobile station, based on measurements of the CSI-RS.

Abstract: Systems and methods for providing Channel State Information (CSI) feedback in a cellular communications network are disclosed. In some embodiments, a base station of a cellular communications network disables inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at the wireless device and receives one or more CSI reports from the wireless device that are generated by the wireless device with inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes disabled in response to the base station disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at the wireless device. In this manner, CSI feedback is improved particularly in embodiments in which the base station transmits a beamformed CSI-RS resource(s) and reuses the same CSI-RS resource(s) for different beams over time.

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: According to certain embodiments, methods and systems for providing device-specific radio network temporary identifiers (C-RNTI) signatures may be provided for interference cancellation. The methods and systems may include assigning a subset of C-RNTIs to a cell. A mapping may be defined between the subset of C-RNTI signatures and a set of C-RNTI indices. Each C-RNTI signature within the subset may be identifiable by a first wireless device via the mapping. The mapping between the subset of C-RNTI signatures and the set C-RNTI indices may be provided to the first wireless device. A C-RNTI indices indicating at least one currently scheduled wireless device may be provided to the first wireless device.

Abstract: Methods for wirelessly transmitting user data and control information using a plurality of transmission layers include encoding bits of control information to form control codewords and encoding bits of user data to form user data codewords. The method also includes generating a plurality of vector symbols based on the control codewords and the user data codewords. Each vector symbol includes a plurality of modulation symbols that are each associated with a transmission layer over which the associated modulation symbol will be transmitted. Generating the plurality of vector symbols includes interleaving bits of the control codewords and bits of the user data codewords so that the control information is carried in modulation symbols associated with the same transmission layers in the vector symbols transmitted during the subframe that carry the control information. The method also includes transmitting the plurality of vector symbols to a receiver over a plurality of transmission layers.

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 teachings herein present a method and apparatus that implement and use a factorized precoder structure that is advantageous in terms of performance and efficiency. In particular, the teachings presented herein disclose an underlying precoder structure that allows for full PA utilization. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder comprises a block diagonal matrix and has 2?k/2? columns, where k is a non-negative integer. Each tuning precoder has the following properties: all non-zero elements are constant modulus; every column has exactly two non-zero elements; and every row has exactly two non-zero elements; two columns either have non-zero elements in the same two rows or do not have any non-zero elements in the same rows; and two columns having non-zero elements in the same two rows are orthogonal to each other. If row m in a tuning precoder column has a non-zero element, so does row m+?k/2?.

Abstract: An object of some embodiments is to enable more dynamic and flexible transmission of reduced-power subframes. Particular embodiments provide a method in a network node. The method comprises transmitting a downlink scheduling assignment for a subframe to a wireless terminal. The scheduling assignment is comprised in control information. The control information further comprises an indication of a power offset that is or will be used for data transmission in the subframe relative to reference signal transmission.

Abstract: A high-power point and one or more low-power points transmit signals that are associated with the same cell-identifier in a heterogeneous cell deployment. The coverage areas corresponding to the low-power points fall at least partly within the coverage area for the high-power point, so that mobile stations within range of a low-power point are also within range of the high-power point, from a downlink perspective. The same CRS signals are transmitted by both the high-power (macro) point and some or all of the low-power (pico) points. At the same time, the network transmits CRS-based PDSCH for a particular UE on both the high-power point as well as on some or all of the low-power points. In some embodiments only a subset of the points, e.g., those points that the UE hears sufficiently well, participate in the PDSCH transmission using CRS for channel estimation.