A CSI feedback method and a CSI feedback device are provided. The CSI feedback method includes: determining a first precoding matrix in a set of first precoding matrices, and determining a first precoding matrix index value corresponding to the first precoding matrix; determining a second precoding matrix in a set of second precoding matrices, and determining a second precoding matrix index value corresponding to the second precoding matrix, the second precoding matrix including a beam selection section for selecting beams from the beam groups for each antenna group and a phase adjustment section for adjusting phases among the plurality of antenna groups; and feeding back the first precoding matrix index value and the second precoding matrix index value to an access device, so as to enable the access device to select corresponding precoding matrices from the set of first precoding matrices and the set of second precoding matrix in accordance with the first precoding matrix index value and the second precoding matrix index value, and implement calculation on the selected precoding matrices to obtain a precoding matrix for data transmission.

A first radio node including processing circuitry configured to configure the first radio node to: obtain a first interference subspace, obtain beamforming weights based on the first interference subspace where the beamforming weights configured to modify a radiation pattern in at least one communication direction of at least one interference source, and perform wireless communications based on the beamforming weights.

Precoding matrix computations for a large number of antenna arrays can be used to generate efficiencies within a wireless network. Utilizing network topology and context data in conjunction with known available network resources and mobile device measurements can facilitate gains in power and spectral efficiency and reduction in computation complexity posed by current procedures. To take advantage of multiple paths, the precoding matrix can be known at the radio units for each mobile device.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

A method of transmission over multiple wireless channels in a multiple antenna system includes storing channel modulation matrices at a transmitter; receiving quantized channel state information at the transmitter from plural receivers; selecting a transmission modulation matrix using the quantized channel state information from the stored channel modulation matrices; and transmitting over the multiple channels to the plural receivers using the selected transmission modulation matrix. In another embodiment, the method includes storing, at one or more receivers, indexes of modulation matrices generated by a capacity enhancing algorithm; upon a selected one of the one or more receivers receiving a transmission from the transmitter, the selected receiver selecting a modulation matrix from the stored modulation matrices that optimizes transmission between the transmitter and the selected receiver; the selected receiver sending an index representing the selected modulation matrix; and receiving the index at the transmitter from the selected receiver.

Precoding matrix computations for a large number of antenna arrays can be used to generate efficiencies within a wireless network. Utilizing network topology and context data in conjunction with known available network resources and mobile device measurements can facilitate gains in power and spectral efficiency and reduction in computation complexity posed by current procedures. To take advantage of multiple paths, the precoding matrix can be known at the radio units for each mobile device.

An enhanced linear combination codebook framework can support power allocation between transmission layers. Scaling between the layers of the codebook can be unequal so that power allocated between the layers can depend on the channel. For example, the network can configure the codebook to use radio resource control signaling to send codebook data to the user equipment.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Precoding matrix computations for a large number of antenna arrays can be used to generate efficiencies within a wireless network. Utilizing network topology and context data in conjunction with known available network resources and mobile device measurements can facilitate gains in power and spectral efficiency and reduction in computation complexity posed by current procedures. To take advantage of multiple paths, the precoding matrix can be known at the radio units for each mobile device.

Systems and methods are described for coordinating transmissions in distributed wireless systems via user clustering. For example, a method according to one embodiment of the invention comprises: measuring link quality between a target user and a plurality of distributed-input distributed-output (DIDO) distributed antennas of base transceiver stations (BTSs); using the link quality measurements to define a user cluster; measuring channel state information (CSI) between each user and each DIDO antenna within a defined user cluster; and precoding data transmissions between each DIDO antenna and each user within the user cluster based on the measured CSI.