Nec Corporation

Duong Pham

Yasushi Maruta

Arun Gurung

Sampath Rangarajan

Narayan Prasad

Robert Arnott

Caroline Liang

Filip Zalio

Chaitanya Rao

Thirukkumaran Sivahumaran

Patricia Wells

A MIMO system () and a method of generating a precoder for use in a MIMO system (), when communicating with a UE (), are provided. The method comprises receiving, from the UE (), channel information relating to a channel on which data is transmitted; decomposing the channel information into components representing a transmission component and a signal strength component; and generating the precoder according to the transmission component and the signal strength component.

Method and system for MIMO communication

A method and system for data communication in a Multi-user Multiple-Input and Multiple-Output (MU-MIMO) system is provided. The method includes receiving, from a first UE of the plurality of UEs, first and second channel information relating to first and second subsets of antennae; generating first and second sub-precoders according to the first and second channel information; generating a precoder according at least in part to the first and second sub-precoders; and transmitting data to the first UE using the precoder.

Method and system for MU-MIMO communication

A system includes an eNB which is operable to communicate with one or UEs and a set of multiple transmit antennas associated with the eNB. The antennas are partitioned into multiple antenna subsets. In a first form of the method, one of the antennas is designated as a reference antenna and the reference antenna forms part of each antenna subset. In a second form of the method, one of the subsets is designated as a reference subset. The UE(s) are operable to compute multiple PMIs for the respective multiple subsets and to report the multiple PMIs to the eNB for the eNB to use in precoding. The first form involves computing a PMI for a given antenna subset independently of the PMIs of any of the other antenna subsets. The second form involves computing a PMI for a given subset based on or using the PMI for the reference subset.

Computing PMIs, particularly in wireless communications systems having three-dimensional communications channels, using a reference antenna or a reference antenna subset

A method and system for data communication in a Multiple-Input and Multiple-Output (MIMO) system is provided. The method includes receiving, from a first UE, first channel information relating to a first subset of a plurality of antennae of the MIMO system and second channel information relating to a second subset of a plurality of antennae. The method further includes generating first and second sub-precoders according to the first and second channel information, respectively. A precoder is then generated according at least in part to the first sub-precoder and the second sub-precoder, and data is transmitted to the first UE using the precoder.

A method and transmitting device are provided for coordinated multi-point transmission scheduling by a transmitting device over one or more heterogeneous wireless networks that include a set of clusters. Each of the clusters has a set of transmission points for serving a set of user equipment devices. The method includes determining constraints imposed on any of the user equipment devices. The method further includes receiving channel state information feedback from the user equipment devices. The method also includes obtaining user weights and buffer sizes. The method additionally includes iteratively determining a weighted sum of user rates based on the constraints, the channel state information feedback, the user weights, and the buffer sizes. The iteratively determining step determines the weighted sum of user rates based on an initial weighted sum of user rates determined for the user equipment devices without the constraints.

Standards compliant coordinated multi-point scheduling over LTE heterogeneous wireless networks

A method for computing precoder matrix indicators (PMIs) in a wireless communication system is disclosed. The wireless communication system includes a base station (eNB) which is operable to communicate with one or more user equipments (UEs), and a set of transmit antennas associated with the eNB that have been partitioned into multiple antenna subsets. The UE(s) are operable to compute and report multiple PMIs for the said multiple antenna subsets to the eNB for the eNB to use in precoding. The method comprises computing a PMI for a given antenna subset using other already-computed PMI(s) for other(s) of the antenna subsets, such that the PMIs reported by the UE to the eNB account for correlation between the antenna subsets.

Computing PMIs, particularly in wireless communications systems having a three-dimensional communications channel

There is provided generating precoders for joint transmission (JT) in a downlink coordinated multi-point transmission/reception (DL COMP) wireless communications system. The system includes a plurality of transmission points (TPs) operable to communicate with a plurality of user equipments (UEs). Each UE has one of the TPs as its serving TP. The method includes transmitting channel state information (CSI) from each UE to its serving TP, wherein the transmitted CSI includes precoder matrix indicators (PMI), and using the PMI to generate precoders for transmission of data from the plurality of TPs to the plurality of UEs.

Generating precoders for joint transmission from multiple transmission points to multiple user equipments in a downlink coordinated multipoint transmission/reception communications system

A method according to the present invention is for selecting User Equipment (UE) for scheduling/precoding within the coverage area of a communications node having a predefined codebook. The method includes: receiving at the communications node feedback information from each of the UEs within the coverage area of the communications node wherein the feedback information includes at least one precoder matrix indicator (PMI); generating at the communications node a precoder matrix based on the reported precoder matrix indicator from each UE; determining at the communications node correlation values for each UE in the coverage utilizing the precoder matrix; identifying a pair of UEs having minimum correlation values; and selecting the identified UEs for scheduling/precoding if the minimum correlation value is less than or equal to a threshold value.

Method for improving transmission capacity in a DL MU-MIMO communications system

This method of generating precoders is used in optimising transmission capacity between an eNodeB and UEs in a DL MU-MIMO communication system. The method includes the steps of computing correlation values between pairs of precoding matrices (PMs) of the reported precoding matrix indicators (PMIs) (step), selecting a PM pair having a minimum correlation value (step). If the minimum correlation value is less than a lower threshold T, the method uses a PM corresponding to the received PMI (step). If the minimum correlation value is greater than Tand less than an upper threshold T, the method includes the steps of computing correlation values of the reported PMI and Channel Matrices (CMs) from a fixed codebook of representative CMs (step), selecting a CM pair having a maximum correlation value (step), and computing precoders from the selected CM pair (step).

Generating precoders for use in optimising transmission capacity between an eNodeBb and UE in a DL MU-MIMO communications system

A method of inserting downlink demodulation Reference Signals into Resource Blocks of slots within Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM transmitter forming part of an OFDM system, the transmitter having at least one antenna and the system having at least one transmission layer, includes the steps of: for each antenna, inserting cell-specific Reference Signals at sub-carriers indices evenly spaced by a fixed sub-carrier spacing; and selectively inserting UE-specific Reference Signals into nodes of a rectangular lattice formed from unused Resource Elements in a group of Resource Blocks of two consecutive slots, the nodes being located at the same sub-carrier indices as the cell-specific Reference Signals and further being equally spaced by a fixed number of symbol indices within the group of Resource Blocks.

Insertion of downlink demodulation reference signals into OFDM frames

A method includes: receiving symbols from antenna(s); calculating average-channel estimates of the symbols over a measurement period; forming a channel matrix from the average-channel estimates; calculating a power ratio between a closed-loop mode and an open-loop mode for each PCI using the channel matrix; calculating RSCP value(s) and ISCP value(s) corresponding to the antenna(s); averaging the RSCP value(s) and ISCP value(s) over the antenna(s) to provide averaged RSCP and ISCP; calculating open-loop SINR from the averaged RSCP and ISCP; calculating SINR for stream(s) for each PCI from the power ratio and the open-loop SINR; determining TBS for a single stream from a single-stream-CQI table using calculated SINR; determining TBS for all streams from a dual-stream-CQI table using calculated SINR; comparing the TBS of the single stream and TBS of the dual stream to determine whether to select single stream or dual stream; and determining PCI and CQI for the stream(s).

Method of PCI and CQI estimation in CDMA systems

A device for performing channel estimation in an OFDM system includes a non-volatile memory, a G matrix selector and a channel estimate generator. The non-volatile memory stores a set of G matrices indexed by signal to noise ratio, the G matrices being precalculated for a plurality of signal to noise ratios using a fixed Doppler frequency and a fixed delay spread. The G matrix selector uses a quantised signal to noise ratio to select a G matrix from the set of G matrices stored in the non-volatile memory. The channel estimate generator multiplies the selected G matrix by LS estimates for the reference signal to obtain a channel estimation.

Channel estimation for OFDM systems

A method of estimating channel conditions for use in a MIMO communication system includes the steps of, at a receiver: computing a SINR metric for all pre-coding matrices; computing a first capacity metric for the bandwidth from the SINR metrics, and selecting a rank which maximizes the first capacity metric; computing a second capacity metric for each frequency channel from the SINR metrics and the selected rank, and selecting one or more pre-coding matrices which maximize the second capacity metric; computing a third capacity metric from the second capacity metric, selected rank and selected pre-coding matrices for each transmission layer within each frequency channel, and selecting one or more frequency channels which maximize the third capacity metric; and transmitting the selected rank, selected pre-coding matrices and selected frequency channels to the transmitter for use in subsequent data transmissions.

Growing community of inventors

Victoria, Australia

Duong Pham