Abstract: A method for wirelessly transmitting data and control information using a plurality of transmission layers includes determining a number of bits in one or more user data codewords to be transmitted during a subframe and calculating, for each of M control signals to be transmitted during the subframe, a value (Q?), based at least in part, on the number of bits in the one or more user data codewords, and an estimated number of user data vector symbols onto which the one or more user data codewords will be mapped. The estimate of the number of user data vector symbols for a particular one of the M control signals depends, at least in part, on a number of control vector symbols to be allocated to one or more others of the M control signals.

Abstract: It is presented a user equipment comprising: a processor; and an instruction memory. The instruction memory stores instructions that, when executed, causes the user equipment to: receive at least one command from a network node; obtain at least a first measurement of channel state information and a second measurement of channel state information as a response to the at least one command; determine whether an interference corresponding to the second measurement of channel state information occurs during a data reception phase; and decode received signals, when an interference corresponding to the second measurement of channel state information occurs, based on the second measurement of channel state information.

Abstract: A method for wirelessly transmitting data using a plurality of transmission layers includes estimating a number of data vector symbols to be allocated to one or more user data codewords during the subframe and determining a number of bits in the one or more user data codewords. The method also includes calculating a nominal number of control vector symbols to allocate to control information based, at least in part, on the estimated number of data vector symbols and the determined number of bits in the one or more user data codewords. Additionally, the method includes determining an offset value based, at least in part, on a number of layers over which the wireless terminal will be transmitting during the subframe and calculating a final number of control vector symbols by multiplying the nominal number of control vector symbols and the offset value.

Abstract: As a basis for precoder quantization, a channel matrix representing multi-antenna channel characteristics between a transmitter and a receiver in the mobile communications network is estimated (S1). A channel-assisted vector selection procedure (S2-S4) for iteratively selecting precoding vectors for a precoding matrix is performed. Each of a number of iterations of the novel iterative vector selection procedure generally involves evaluation (S2) of the performance of each one of a set of candidate vectors included in a given vector codebook with respect to a predetermined performance measure that is dependent on the estimated channel matrix, and selection (S3) of one of the set of candidate vectors as a respective precoding vector for the precoding matrix based on the evaluated performance. Information representative of a set of selected precoding vectors is then compiled (S5) to form a quantized representation of the precoding matrix for transmission to the transmitter side.

Abstract: Some of the example embodiments presented herein are directed towards an eNodeB (401), and corresponding method therein, for establishing beamforming for downlink communications in a multiple antenna system. The eNodeB (401) may be configured to 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 (401) may thereafter 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 (505), and corresponding methods therein, for establishing beamforming for downlink communications. The user equipment (505) may be configured to receive the plurality of reference signals and provide signal assessments of the reference signals based on measurements performed by the user equipment (505).

Abstract: Some of the example embodiments presented herein are directed towards an eNodeB (401), and corresponding method therein, for providing data transmission in a multiple antenna system. The eNodeB (401) may be configured to receive a plurality of signal quality assessments and a CSI report from a user equipment. Based on the received data the eNodeB (401) may determine a received power difference between the received data. The eNodeB (401) may further determine a beamforming direction for subsequent data transmissions. Based on the power difference, the eNodeB (401) may account for the received power difference in the subsequent data transmissions, thus improving data communications towards the user equipment.

Abstract: Example embodiments presented herein are directed towards an eNodeB (401), and method therein, for establishing beamforming for downlink communications in a multiple antenna system. The eNodeB may be configured to receive, from a user equipment, a plurality of signal quality assessments which correspond to a distinct direction within at least one correlated domain (e.g., an elevation and/or azimuth domain). Based on the signal quality assessments, at least one first and second signal quality assessment may be identified according to a predetermined signal characteristic. Thereafter, a transmission direction may be determined based on the at least one first and second signal quality assessment and associated directions within the at least one correlated domain. Based on the determined transmission direction, downlink communications may be transmitted to the user equipment.

Abstract: According to one or more aspects, the teachings herein improve user equipment (UE) Channel State Information (CSI) feedback, by letting the precoder part of a CSI feedback report comprise factorized precoder feedback. In one or more such embodiments, the factorized precoder feedback corresponds to at least two precoder matrices, including a recommended “conversion” precoder matrix and a recommended “tuning” precoder matrix. The recommended conversion precoder matrix restricts the number of channel dimensions considered by the recommended tuning precoder matrix and, in turn, the recommended tuning precoder matrix matches the recommended precoder matrix to an effective channel that is defined in part by said recommended conversion precoder matrix.

Abstract: In a heterogeneous cell deployment a mobile terminal may need to receive control data transmissions from a macro node at the same time as a pico node is transmitting user data for the mobile terminal, using the same frequency or set of frequencies. This can result in a problematic interference situation. According to several embodiments of the present invention, at least one of two general approaches is used to mitigate the interference situation described above. In a first approach, the pico node's transmission power is reduced in some time intervals, thereby reducing the interference to a level where reception from the macro node is possible. In a second approach, which may be combined with the first approach in some cases, the data transmitted from the macro node is provided by the pico node, either alone or in combination with the macro node.

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: 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 associated interference measurement resource, IMR. According to the method, the wireless device obtains an interference power adjustment value. The wireless device estimates interference and noise based on the IMR, and on the interference power adjustment value. Furthermore, the wireless device determines channel state information based on an estimated effective channel measured based on the reference signal resource, and on the estimated interference and noise. Finally, the wireless device transmits the channel state information to a network node.

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 certain codebook reuse across different transmission scenarios, including for transmission from a single Uniform Linear Array (ULA) of transmit antennas and transmission from cross-polarized subgroups of such antennas. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder includes antenna-subgroup precoders of size NT/2, where NT represents the number of overall antenna ports considered. Correspondingly, the tuning precoder controls the offset of beam phases between the antenna-subgroup precoders, allowing the conversion precoder to be used with cross-polarized arrays of NT/2 antenna elements and with co-polarized arrays of NT antenna elements.

Abstract: The initialization of the CoMP Resource Management Set for a given mobile terminal is based, at least in part, on an estimation of the mobile terminal's geographical location, which can be estimated using network positioning of the mobile terminal. One example method begins with the acquisition (410) by a network node of a geographical position estimate for the mobile terminal of interest. The network node then selects (420) a set of one or more CSI-RS resources for measurement by the mobile terminal, based on the estimated geographical position of the mobile terminal. Finally, the network node configures the mobile terminal to measure the selected CSI-RS resources by sending (430) control information identifying the set to the mobile terminal.

Abstract: One aspect of the teachings herein relates to signaling codebook restrictions, to restrict the precoder recommendations being fed back from a remote transceiver, so that precoder selections made by the remote receiver are restricted to permitted subsets of overall precoders within a defined set of overall precoders, or to permitted subsets within larger sets of conversion precoders and tuning precoders, for the case where the overall precoders are represented in factorized form by conversion and tuning precoders. As a non-limiting example, these teachings advantageously provide for precoder restrictions in LTE or LTE-Advanced networks, where ongoing development targets the use of larger, richer sets of precoders, and where the disclosed mechanisms for determining, signaling, and responding to subset restrictions provide significant operational advantages.

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: 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: 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: Data is transmitted over multiple input multiple output (MIMO) channels. Plural bit streams are modulated into multiple data symbol vectors. Each vector has a transmission rank with one vector for each MIMO channel. Transmission rank is the number of elements in a data symbol vector corresponding to the number of data streams being transmitted in parallel over each MIMO channel. The multiple data symbol vectors are preceded into multiple precoded symbol vectors using a plurality of precoder cycling sets, one set for each transmission rank including multiple different precoders. The precoders in each precoder cycling set are well-separated with respect to a plurality of distance measures. The precoding includes precoding each data symbol vector of a transmission rank with a precoder belonging to the precoder cycling set of that transmission rank. The precoded symbol vectors are then transmitted over the MIMO channels.

Abstract: A method for wirelessly transmitting data using a plurality of transmission layers includes estimating a number of data vector symbols to be allocated to one or more user data codewords during the subframe and determining a number of bits in the one or more user data codewords. The method also includes calculating a nominal number of control vector symbols to allocate to control information based, at least in part, on the estimated number of data vector symbols and the determined number of bits in the one or more user data codewords. Additionally, the method includes determining an offset value based, at least in part, on a number of layers over which the wireless terminal will be transmitting during the subframe and calculating a final number of control vector symbols by multiplying the nominal number of control vector symbols and the offset value.

Abstract: The invention relates to methods and arrangements for rank adaptation for transmissions over a multipie-input-muttipie-output, M1MO, channel in a wireless communications system. A receiving node (270) performs (310) measurements on reference signals received from a sending node (200), The receiving node performs (330a(330b) a first feedback computation for a first rank and at least one second feedback computation for at yeast one second rank based on the measurements. The first feedback computation includes applying a first relation between assumed transmitted energy for data and transmitted energy for the reference signals that is specific to the first rank. A second relation between assumed transmitted energy for data and transmitted energy for the reference signals is specific to the at least one second rank. The receiving node selects (340) one rank based on the feedback computations and indicates (350) the selected rank in a feedback report to the sending node.