Nokia Solutions and Networks Oy

Nokia Technologies Oy

Weiqiang Mao

Lijun Wang

Yong Chen

Stefan Wesemann

Zhijun Liao

Tao Yu

Youbao Luo

Embodiments of the present disclosure relate to methods, devices and computer readable mediums for a unified nonlinear precoding procedure. The method comprises generating sequences of OFDM symbols on subcarriers on a downlink channel from the network device to a terminal device; determining a processing matrix of the downlink channel at least partially based on characteristics of the downlink channel; obtaining reference values of parameters of a signal generation model; and iteratively performing the following for a number of times: adjusting, based on the sequences of OFDM symbols and the processing matrix, the reference values of the parameters of the signal generation model, the parameters being signals for transmitting via transmitting ports of the network device on the downlink channel to the terminal device; and updating the reference values of the parameters of the signal generation model by clipping the adjusted values of the parameters of the signal generation model.

PAPR reduction of MIMO-OFDM

Embodiments of the present disclosure relate to a method, an apparatus and a computer readable storage medium of user selection for MU-MIMO communications. In example embodiments, a method is provided. The method comprises determining a set of candidate terminal devices; and iteratively performing the following at least once until an end condition is met: generating, based on respective channel estimations for the set of candidate terminal devices, a covariance matrix indicating interdependency among the set of candidate terminal devices; determining a minimum eigenvalue of the covariance matrix and an eigenvector corresponding to the minimum eigenvalue, the eigenvector indicating a set of measurements for interdependency among the set of candidate terminal devices; and updating the set of candidate terminal devices by removing, from the set of candidate terminal devices, a candidate terminal device associated with a maximum measurement in the set of measurements.

User selection for MU-MIMO communications

According to embodiments of the present disclosure, downlink beamforming in MU-MIMO systems is proposed. Embodiments of the present disclosure take practical receivers into consideration, to further mitigate the interferences sensed by terminal devices. The beamforming scheme according to embodiments of the present disclosure has many advantages. For example, embodiments of the present disclosure tackle interferences from terminal device view, to mitigate the interferences which really affect the received signals of terminal devices. Embodiments of the present disclosure do not assume that terminal devices utilize Eigen receivers but consider more practical receivers used by the terminal devices to mitigate the interferences. Embodiments of the present disclosure have high flexibility, different interference cancelling methods can be used to replace the ZF method.

Downlink beamforming in MU-MIMO system

Embodiments of the present disclosure relate to a method, device and computer readable medium for user selection for MU-MIMO communications. In example embodiments, the method comprises for a set of candidate terminal devices, performing scheduling by: obtaining a set of received signals; determining a set of measurements for relevance among the candidate terminal devices based at least on the set of received signals and channel estimation for the set of candidate terminal devices; determining a maximum measurement in the set of measurements; and updating the set of candidate terminal devices by removing a candidate terminal device associated with the maximum measurement from the set of candidate terminal devices.

Embodiments of the present disclosure relate to a device, method, apparatus and computer readable storage medium for channel estimation in a multiple input multiple output (MIMO) system. The MIMO system comprises a receiver configured with a plurality of receiving antennas and a transmitter configured with a plurality of transmitting antennas. In example embodiments, a plurality of data symbols are detected based on channel estimation from a plurality of signals received by the plurality of receiving antenna from the plurality of transmitting antennas. The plurality of detected data symbols are adjusted based on a set of constellation points for a modulation mode used by the transmitter and associated with the plurality of signals. The channel estimation is updated based on the plurality of adjusted data symbols.

Anchor process of data symbols in channel estimation

Example embodiments of the present disclosure relate to a transmitter, method, apparatus and computer readable storage medium for quantized precoding in a massive multiple-input multiple-output (MIMO) system. In example embodiments, a transmitter determines a normalized factor for precoding of a plurality of signals intended for a plurality of receivers. The first device precodes the plurality of intended signals using the normalized factor by iteratively performing acts. The acts include determining, by using the normalized factor, a descending direction of a difference between the plurality of intended signals and corresponding signals received at the plurality of receivers, a descending rate of the difference being above a threshold rate in the descending direction, and determining a plurality of precoded signals based on the descending direction. Then, the first device quantizes the plurality of precoded signals for transmission by the transmitter to the plurality of receivers.

Quantized precoding in massive MIMO system

Embodiments of the present disclosure relate to a method, transmitter, apparatus and computer readable storage media for signal precoding of massive MIMO. The transmitter comprises a first number of transmitting antennas. In example embodiments, the transmitter iteratively performs the following operations: determining a first number of signals to be transmitted by the first number of antennas in a second number of streams based on a second number of original signals, determining whether at least one feature of the first number of signals is to be regulated, and in response to determining that the at least one feature of the first number of signals is to be regulated, adjusting at least one of the first number of signals in order to regulate the at least one feature of the first number of signals. Accordingly, the first number of signals are transmitted by the first number of antennas in the second number of streams.

Precoding of massive MIMO

Embodiments of the present disclosure relate to methods, apparatuses and computer program products for signal detection in a wireless communication system. A method implemented at a receiver device includes obtaining a set of received signals; determining a channel on which the set of received signals are transported; and detecting a set of transmitted signals from the set of received signals in an iterative manner based on the determined channel, a modulation mode for the set of transmitted signals, and the set of received signals, by using a gradient descent (GD) algorithm. Embodiments of the present disclosure may reduce computation complexity required in signal detection and/or improve detection performance.

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Zhejiang, China

Weiqiang Mao