A method and apparatus for determining a codebook and a communication system includes: determining a first codebook used for radio frequency precoding on the basis of the number of the antenna elements in the planar antenna array and/or the number of radio frequency chains; wherein, the antenna elements in the same polarization direction in an antenna column in the vertical direction form one or more virtual antenna ports, which are being connected with multiple radio frequency chains; and determining a second codebook used for baseband precoding on the basis of the number of the antenna elements in the planar antenna array and/or the number of the radio frequency chains. With certain embodiments, hybrid precoding of a baseband and a radio frequency may be performed, which is suitable for application of a large-scale MIMO system, thereby achieving an effective tradeoff between system performance and complexity.

A wireless communication system, an apparatus and a method for integrating communication and sensing functions in the wireless communication system are provided. The communication device includes a communication unit for bi-directional communication, and a radar unit for sensing. The communication unit and the radar unit may commonly include a common transmit chain which generates a transmit signal. The transmit signal may have a first polarization. The communication unit may include a communication receive chain, and if a receive signal has the first polarization in response to the transmit signal, the communication receive chain may receive the receive signal having the first polarization via the hybrid coupler and perform communication and if the receive signal corresponding to the transmit signal has second polarization different from the first polarization, a sensing receive chain of the radar unit may receive the receive signal having the second polarization perform sensing by the radar unit.

A signal generation method is used in a transmission device that transmits a plurality of transmission signals from a plurality of antennas at the same frequency and at the same time, in the case where larger power change is performed on a first transmission signal than on a second transmission signal during generation process of the first transmission signal and the second transmission signal, the first transmission signal and the second transmission signal are mapped before the power change such that a minimum Euclidian distance between possible signal points for the first signal is longer than a minimum Euclidian distance between possible signal points for the second signal.

Facilitating generic feedback to enable reciprocity and over the air calibration for advanced networks (e.g., 4G, 5G, and beyond) is provided herein. Operations of a system can comprise selecting information to include in a channel state information feedback report based on a feedback instance. The operations can also comprise generating the channel state information feedback report as a function of channel statistics of channels. Further, the operations can comprise transmitting the channel state information feedback report to a network device of a communications network.

This disclosure discloses methods and apparatuses for signal processing. In an implementation, a method comprises: generating first indication information, wherein the first indication information indicates L.sub.1 space domain vectors in a space domain vector set, K.sub.1 frequency domain vectors in a frequency domain vector set, and T.sub.1 space-frequency component matrices, wherein a precoding vector of one or more frequency domain units is determined by a weighted sum of the T.sub.1 space-frequency component matrices, wherein the L.sub.1 space domain vectors and the K.sub.1 frequency domain vectors correspond to M.sub.1 space-frequency component matrices that comprise the T.sub.1 space-frequency component matrices, wherein each of the M.sub.1 space-frequency component matrices is uniquely determined by a different combination of one of the L.sub.1 space domain vectors and one of the K.sub.1 frequency domain vectors; and sending the first indication information.

A method for a channel state information (CSI) feedback in an advanced communication system. The method comprises receiving, from a base station (BS), CSI feedback configuration information for a pre-coding matrix indicator (PMI) feedback based on a linear combination (LC) codebook, wherein the PMI comprises a first PMI i.sub.1 and a second PMI i.sub.2. The method further comprises determining, by a user equipment (UE), the first PMI i.sub.1 and the second PMI i.sub.2 indicating an LC pre-coder that corresponds to a weighted linear combination of a first beam and a second beam, where a power of a weight assigned to the first beam is 1 and a power of a weight assigned to the second beam is between 0 and 1 and transmitting, to the BS, the CSI feedback over an uplink channel including the determined first PMI i.sub.1 and second PMI i.sub.2.

A method for a channel state information (CSI) feedback in an advanced communication system. The method comprises receiving, from a base station (BS), CSI feedback configuration information for a precoding matrix indicator (PMI) feedback using a higher layer signaling, wherein the CSI feedback configuration information includes a combination of an oversampling factor (O.sub.1, O.sub.2) and a dual polarized CSI reference signal (CSI-RS) antenna port layout (N.sub.1, N.sub.2), and wherein subscripts 1 and 2 stand for a first dimension and a second dimension, respectively, and a number of dual polarized CSI-RS ports P=2N.sub.1N.sub.2. The method further comprises determining, by a user equipment (UE), the PMI using a Class A codebook and the configured combination of the (O.sub.1, O.sub.2) and (N.sub.1, N.sub.2) and transmitting, to the BS, the CSI feedback over an uplink channel including the determined PMI.

It is possible to reduce the overhead associated with downlink channel estimation in massive Multiple-Input-Multiple-Output (MIMO) networks by processing training sequences according to a transformation matrix. The transformation matrix maps a generic dictionary to a non-generic dictionary associated with an antenna geometry of a MIMO antenna array. The transformation matrix can be computed based on the two dictionaries. In one embodiment, the training reference signal is precoded to obtain a precoded training reference signal, which is then transmitted over a MIMO antenna array. The training precoder used to precode the training reference signal is designed according to the transformation matrix to mitigate a dependence that the training reference signal transmission has on the antenna geometry.

A method and a device for sending parameters of a precoder in a wireless communication system are disclosed. According to one aspect, the method comprises: sending, to a network node, an indication of a subset of beams selected from a plurality of orthogonal beams and an indication of power levels of the selected subset of beams, for a first frequency granularity; and sending, to the network node, an indication of phases of the selected subset of beams, for a second frequency granularity, wherein the indication of the selected beams, the indication of the power levels of the selected subset of beams and the indication of the phases of the selected subset of beams are part of the parameters of the precoder.

A channel information sending method, a data sending method, and a device are provided, to improve feedback precision of a precoding matrix. These include a receiver that receives a reference signal and a memory, configured to store at least one computer instruction which, when executed by the processor, cause the processor to measure the reference signal from the receiver to obtain first channel information and second channel information and send the first channel information and the second channel information to the second device. In some embodiments, the first channel information comprises identification information of N antenna ports in M antenna ports for the reference signal, M is an integer not less than 2, and N is a positive integer not greater than M, the second channel information comprises information about a weighted combination factor used for performing weighted combination on the N antenna ports, the weighted combination factor comprises an amplitude factor and a phase factor, and the first channel information and the second channel information are used to constitute a precoding matrix.