A base station apparatus is capable of adjusting antenna gains in a horizontal direction and a vertical direction of the plurality of antennas included in the base station apparatus, by adjusting a phase and an amplitude of a signal addressed and transmitted to a terminal apparatus, stores a codebook which is shared with the terminal apparatus and describes a plurality of linear filters associated with antenna gains in the horizontal direction and antenna gains in the vertical direction, acquires control information indicating at least one out of a plurality of linear filters described in the codebook, of which notification is sent from the terminal apparatus, performs precoding on the signal addressed to the terminal apparatus, based on the control information and the first codebook, and transmits the signal subjected to the precoding.

A testing device and a method for testing a device under test are provided. The testing device comprises at least two signal generators, at least two numerically controlled oscillators, at least two white gaussian noise generators, at least two digital filters, each of which comprising a respective transfer function H.sub.i, at least two adders, at least two digital-to-analog converters, and an analog processor.

A method for determining an angle of arrival (AOA) of a received signal is disclosed, comprising: generating a baseband information signal by mixing a received signal with a local oscillator (LO) signal, the received signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets; obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample; determining a transmitter phase offset based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; performing a plurality of phase measurements using a plurality of antennas to obtain a plurality of phase measurements; correcting the plurality of phase measurements based on the transmitter phase offset to produce a plurality of corrected phase measurement; and calculating an AOA of the received signal based on the difference between the plurality of corrected phase measurements.

The present disclosure relates to reference symbol indication methods, devices, and systems. One example method includes receiving, by a user equipment, a target parameter including a target reference symbol indication sent by a base station, determining a target transmission mode and target reference symbol information based on the target parameter and a preset reference symbol mapping relationship, generating a target reference symbol based on the target reference symbol information, and demodulating data based on the target reference symbol and the target transmission mode, where the preset reference symbol mapping relationship includes a mapping relationship among a reference symbol indication, reference symbol information, and a transmission mode.

A power control method, a terminal device and a network device are provided. The method includes: a terminal device resets a first closed loop adjustment factor associated with first Sounding Reference Signal Resource Indicator (SRI) information in condition that a first open loop power control parameter associated with the first SRI information or a first downlink Reference Signal (RS) associated with the first

SRI information is reconfigured, the first open loop power control parameter being configured for power control of a Physical Uplink Shared Channel (PUSCH) and the first downlink RS being configured to measure a path loss value for power control of over the PUSCH; and the terminal device determines transmit power of the PUSCH according to the reset first closed loop adjustment factor.

A power control method, a terminal device and a network device are provided. The method includes: a terminal device resets a first closed loop adjustment factor associated with first Sounding Reference Signal Resource Indicator (SRI) information in condition that a first open loop power control parameter associated with the first SRI information or a first downlink Reference Signal (RS) associated with the first SRI information is reconfigured, the first open loop power control parameter being configured for power control of a Physical Uplink Shared Channel (PUSCH) and the first downlink RS being configured to measure a path loss value for power control of over the PUSCH; and the terminal device determines transmit power of the PUSCH according to the reset first closed loop adjustment factor.

A method for determining an angle of arrival (AOA) of a received signal is disclosed, comprising: generating a baseband information signal by mixing a received signal with a local oscillator (LO) signal, the received signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets; obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample; determining a transmitter phase offset based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; performing a plurality of phase measurements using a plurality of antennas to obtain a plurality of phase measurements; correcting the plurality of phase measurements based on the transmitter phase offset to produce a plurality of corrected phase measurement; and calculating an AOA of the received signal based on the difference between the plurality of corrected phase measurements.

An OFDM system synchronization tracking method includes: A1: performing OFDM symbol segmentation on a received digital signal, performing FFT on OFDM symbols obtained through the segmentation, performing step A2 to A5 on each frequency domain OFDM symbol in a frequency domain OFDM symbol sequence; A2: extracting information subcarrier symbols, pilot symbols, a DC subcarrier from a current frequency domain OFDM symbol, detecting and implementing a decision on the information subcarrier symbols, generating a recovery information subcarrier symbol; A3: recovering the OFDM symbol; A4: performing frequency offset estimation and timing offset estimation on the recovery OFDM symbol; A5: performing phase compensation on a next frequency domain OFDM symbol in the frequency domain OFDM symbol sequence by using a frequency offset estimation phase rotation value and a timing offset estimation phase rotation value, setting the compensated frequency domain OFDM symbol to a current frequency domain OFDM symbol, returning to the step A2.

A base station apparatus is capable of adjusting antenna gains in a horizontal direction and a vertical direction of the plurality of antennas included in the base station apparatus, by adjusting a phase and an amplitude of a signal addressed and transmitted to a terminal apparatus, stores a codebook which is shared with the terminal apparatus and describes a plurality of linear filters associated with antenna gains in the horizontal direction and antenna gains in the vertical direction, acquires control information indicating at least one out of a plurality of linear filters described in the codebook, of which notification is sent from the terminal apparatus, performs precoding on the signal addressed to the terminal apparatus, based on the control information and the first codebook, and transmits the signal subjected to the precoding.

A testing device and a method for testing a device under test are provided. The testing device comprises at least two signal generators, at least two numerically controlled oscillators, at least two white gaussian noise generators, at least two digital filters, each of which comprising a respective transfer function H.sub.i at least two adders, at least two digital-to-analog converters, and an analog processor.