CN113726377A

CN113726377A - Phase compensation and calibration method and AP

Info

Publication number: CN113726377A
Application number: CN202010456980.1A
Authority: CN
Inventors: 应腾达; 王凡; 何昭君; 肖峻峰; 冉建军
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-05-26
Filing date: 2020-05-26
Publication date: 2021-11-30
Anticipated expiration: 2040-05-26
Also published as: CN113726377B

Abstract

Provided are a phase compensation method, a calibration method and an AP, wherein the phase compensation method comprises the following steps: and the AP receives the radio-frequency signals from the STA through a plurality of radio-frequency links, measures the radio-frequency signals and obtains a downlink equivalent channel matrix of the channel from the AP to the STA according to a plurality of phase compensation values. The phase calibration method comprises the following steps: the AP processes a first radio frequency signal transmitted by a second radio frequency link by using a first radio frequency link in a first state to obtain a first baseband signal; and the AP determines a single-device phase compensation value when the first gain device is in the gear to be measured according to the first baseband signal and the second baseband signal. The technical scheme is used for improving the accuracy of predicting the downlink equivalent channel matrix by the AP.

Description

Phase compensation and calibration method and AP

Technical Field

The present application relates to the field of communications technologies, and in particular, to a phase compensation method, a calibration method, and an Access Point (AP).

Background

Beamforming (BF) implements transmission or reception of directional signals by a precoding technique, and BF can be divided into two major categories, i.e., Implicit BF (IBF) and Explicit BF (EBF). In a Wireless Local Area Network (WLAN), IBF is an important means for improving air interface performance of a closed-loop multiple-input multiple-output (MIMO) system, and can avoid dimension expansion loss of EBF in channel measurement at a Station (STA) side and reduce air interface interaction overhead.

In the closed-loop MIMO system based on the IBF, an AP receives signals from an STA, and performs channel estimation according to the received signals to acquire an uplink equivalent channel matrix from the STA to the AP. The AP predicts a downlink equivalent channel matrix from the AP to the STA based on channel reciprocity, generates a pre-coding matrix according to the downlink equivalent channel matrix, and then determines a transmitting signal from each radio frequency link (chain) to the STA according to the pre-coding matrix.

However, radio frequency links exist in both the AP and the STA, and radio frequency delay is generated when the radio frequency links process signals, and the radio frequency delay causes phase jump of the signals. The AP carries out channel estimation based on the signals with the phase jump, and the accuracy of predicting a downlink equivalent channel matrix by the AP is influenced.

Disclosure of Invention

The application provides a phase compensation and calibration method and an AP (access point), which are used for improving the accuracy of predicting a downlink equivalent channel matrix by the AP.

In a first aspect, the present application provides a phase compensation method, including:

the AP receives radio frequency signals from the STA through a plurality of radio frequency links, wherein each radio frequency link in the plurality of radio frequency links comprises at least two gain devices;

the AP measures the radio frequency signal and obtains a downlink equivalent channel matrix of a channel from the AP to the STA according to a plurality of phase compensation values, where the downlink equivalent channel matrix is a transpose of an uplink equivalent channel matrix of a channel from the STA to the AP, the plurality of phase compensation values correspond to the plurality of radio frequency links one to one, the uplink equivalent channel matrix includes a plurality of row vectors, the plurality of row vectors correspond to the plurality of radio frequency links one to one, each row vector of the uplink equivalent channel matrix is adjusted by a phase compensation value of a corresponding radio frequency link, and each phase compensation value of the plurality of phase compensation values is determined based on a sum of respective single-device phase compensation values of at least two gain devices in the corresponding radio frequency link.

Based on the technical scheme, the AP receives radio frequency signals from the STA through each radio frequency link, measures the radio frequency signals to obtain an uplink equivalent channel matrix, adjusts the uplink equivalent channel matrix according to the phase compensation value of each radio frequency link, and obtains a downlink equivalent channel matrix after the adjusted uplink equivalent channel matrix is rotated, so that the accuracy of the downlink equivalent channel matrix is improved.

In an optional implementation manner, the phase compensation value of the single device is a function of variables, where the variables include a frequency point of a working channel and a receiving gear of a corresponding gain device.

Based on the technical scheme, the AP determines the single-device phase compensation value of the gain device according to the frequency point and the receiving gear of the working channel, so that the accuracy of the single-device phase compensation value of the gain device is improved, the accuracy of the phase compensation value of the radio frequency link is further improved, and the accuracy of determining the downlink equivalent channel matrix by the AP is equivalently improved.

In an alternative implementation, the variable further includes temperature.

Based on the technical scheme, the influence of different temperatures on the single-device phase compensation value of the gain device is considered, namely, the AP determines the single-device phase compensation value of the gain device according to the temperature, the frequency point of the working channel and the receiving gear, so that the accuracy of the single-device phase compensation value of the gain device is further improved.

In an alternative implementation, the gain device includes an external low noise amplifier, an internal low noise amplifier, or a variable gain amplifier.

In an optional implementation manner, each of the plurality of phase compensation values is determined based on a sum of single-device phase compensation values of at least two respective gain devices in a corresponding radio frequency link, and includes:

each phase compensation value in the plurality of phase compensation values is the sum of the phase compensation values of the single devices of at least two gain devices in the corresponding radio frequency link and an adjustment value obtained according to the sub-carrier to which the uplink equivalent channel matrix belongs.

Based on the technical scheme, the AP measures the radio frequency signals to obtain an uplink equivalent channel matrix corresponding to each subcarrier; the AP determines the phase adjustment value of each subcarrier according to the subcarrier to which each uplink equivalent channel matrix belongs; and then adding the sum of the phase compensation values of the single devices of at least two gain devices in the radio frequency link to the phase adjustment value of each subcarrier to obtain the phase adjustment value of each subcarrier. The phase adjustment value of each subcarrier is used for adjusting the uplink equivalent channel matrix of the corresponding subcarrier, and the accuracy of determining the downlink equivalent channel matrix by the AP is further improved.

In a second aspect, the present application provides a phase calibration method, comprising:

the AP processes a first radio frequency signal transmitted by a second radio frequency link by using a first radio frequency link in a first state to obtain a first baseband signal, wherein the first radio frequency link comprises at least two gain devices, the at least two gain devices comprise a first gain device, a receiving gear of the first gain device in the first radio frequency link in the first state is in a gear to be tested, and receiving gears of gain devices except the first gain device are in respective preset gears;

the AP determines a single-device phase compensation value when the first gain device is in a gear to be measured according to the first baseband signal and the second baseband signal; the second baseband signal is obtained by the AP processing a second radio frequency signal transmitted by the second radio frequency link with the first radio frequency link in a second state, where receiving gears of all gain devices in the first radio frequency link in the second state are in respective preset gears; the initial phases of the first radio frequency signal and the second radio frequency signal are the same.

Based on the technical scheme, the AP determines the phase jump generated when the gain device is in the gear to be measured compared with the gain device in the preset gear according to the first baseband signal and the second baseband signal, and further determines the phase compensation value of the single device when the gain device is in the gear to be measured. The phase compensation value of the single device can be used for adjusting the uplink equivalent channel matrix, so that the downlink equivalent channel matrix with higher accuracy is predicted.

In an alternative implementation manner, the single-device phase compensation value when the first gain device is in the gear to be measured is determined according to a phase difference between the phase of the first baseband signal and the phase of the second baseband signal.

Based on the technical scheme, the AP determines a single-device phase compensation value when the first gain device is in the gear to be measured according to the phase difference between the phase of the first baseband signal and the phase of the second baseband signal, namely determines phase jump generated when the first gain device is in the preset gear and the gear to be measured, and therefore the single-device phase compensation value is applied to adjustment of the uplink equivalent channel matrix.

In an alternative implementation, the first radio frequency signal or the second radio frequency signal includes a plurality of identical Long Training Fields (LTFs).

Based on the technical scheme, the AP performs multi-symbol superposition based on a plurality of same LTFs, and the signal-to-noise ratio is improved.

In a third aspect, the present application provides an AP, comprising:

a communication unit and a processing unit;

the communication unit is used for receiving radio frequency signals from the STA through a plurality of radio frequency links, and each radio frequency link in the plurality of radio frequency links comprises at least two gain devices;

the processing unit is configured to measure the radio frequency signal and obtain a downlink equivalent channel matrix of a channel from the AP to the STA according to a plurality of phase compensation values, where the downlink equivalent channel matrix is a transpose of an uplink equivalent channel matrix of a channel from the STA to the AP, a relationship between the plurality of phase compensation values and the plurality of radio frequency links is in a one-to-one correspondence, the uplink equivalent channel matrix includes a plurality of row vectors, a relationship between the plurality of row vectors and the plurality of radio frequency links is in a one-to-one correspondence, each row vector of the uplink equivalent channel matrix is adjusted by a phase compensation value of a corresponding radio frequency link, and each phase compensation value of the plurality of phase compensation values is determined based on a sum of phase compensation values of respective single devices of at least two gain devices in the corresponding radio frequency link.

In an alternative implementation, the variable further includes a temperature.

In an optional implementation manner, each of the plurality of phase compensation values is a sum of respective single-device phase compensation values of at least two gain devices in a corresponding radio frequency link, and an adjustment value obtained according to a subcarrier to which the uplink equivalent channel matrix belongs.

In a fourth aspect, the present application provides an AP, comprising:

a communication unit and a processing unit;

the communication unit is used for transmitting a first radio frequency signal by using a second radio frequency link; and receiving the first radio frequency signal with a first radio frequency link;

the processing unit is configured to process the first radio frequency signal by using a first radio frequency link in a first state to obtain a first baseband signal, where the first radio frequency link includes at least two gain devices, the at least two gain devices include a first gain device, a receiving tap position of the first gain device in the first radio frequency link in the first state is at a to-be-tested tap position, and receiving tap positions of gain devices other than the first gain device are at respective preset tap positions;

the processing unit is further configured to determine a single device phase compensation value of the first gain device when the first gain device is in a gear to be measured according to the first baseband signal and the second baseband signal; the second baseband signal is obtained by processing, by the processing unit, a second radio frequency signal transmitted by the second radio frequency link by using the first radio frequency link in a second state, where receiving gears of all gain devices in the first radio frequency link in the second state are in respective preset gears; the initial phases of the first radio frequency signal and the second radio frequency signal are the same.

In an alternative implementation, the first radio frequency signal or the second radio frequency signal includes a plurality of identical LTFs.

In a fifth aspect, the present application provides an AP, comprising:

a processor, a plurality of radio frequency links;

the radio frequency links are used for receiving radio frequency signals from the STA, and each radio frequency link in the radio frequency links comprises at least two gain devices;

the processor is configured to measure the radio frequency signal and obtain a downlink equivalent channel matrix of a channel from the AP to the STA according to a plurality of phase compensation values, where the downlink equivalent channel matrix is a transpose of an uplink equivalent channel matrix of a channel from the STA to the AP, a relationship between the plurality of phase compensation values and the plurality of radio frequency links is in one-to-one correspondence, the uplink equivalent channel matrix includes a plurality of row vectors, a relationship between the plurality of row vectors and the plurality of radio frequency links is in one-to-one correspondence, each row vector of the uplink equivalent channel matrix is adjusted by a phase compensation value of a corresponding radio frequency link, and each phase compensation value of the plurality of phase compensation values is determined based on a sum of phase compensation values of single devices of at least two gain devices in the corresponding radio frequency link.

In an alternative implementation, the variable further includes a temperature.

In a sixth aspect, the present application provides an AP, comprising:

the system comprises a processor, a first radio frequency link and a second radio frequency link;

the second radio frequency link is used for transmitting a first radio frequency signal;

the first radio frequency link in the first state is used for receiving the first radio frequency signal and processing the first radio frequency signal to obtain a first baseband signal; the first radio frequency link comprises at least two gain devices, the at least two gain devices comprise a first gain device, a receiving gear of the first gain device in the first radio frequency link in the first state is in a gear to be tested, and receiving gears of gain devices except the first gain device are in respective preset gears;

the processor is used for determining a single-device phase compensation value when the first gain device is in a gear to be measured according to the first baseband signal and the second baseband signal; the second baseband signal is obtained by processing, by the first radio frequency link in the second state, a second radio frequency signal transmitted by the second radio frequency link, where receiving gears of all gain devices in the first radio frequency link in the second state are in respective preset gears; the initial phases of the first radio frequency signal and the second radio frequency signal are the same.

In a seventh aspect, the present application provides a computer-readable storage medium having stored thereon a computer program or instructions which, when executed, cause the method of the first or second aspect to be carried out.

In an eighth aspect, the present application provides a computer program product comprising a computer program or instructions that, when executed, cause the method of the first or second aspect to be carried out.

For technical effects that can be achieved by any one of the third aspect to the eighth aspect, reference may be made to the description of the advantageous effects in the first aspect or the second aspect, and details are not repeated here.

Drawings

Fig. 1 is a system diagram of a WLAN deployment scenario provided in an embodiment of the present application;

fig. 2 is an interaction diagram of an AP and an STA according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a radio frequency link in an AP according to an embodiment of the present disclosure;

fig. 4 is a schematic diagram illustrating reciprocity calibration performed by an AP according to an embodiment of the present disclosure;

fig. 5 is a schematic diagram illustrating a flow of a phase calibration method according to an embodiment of the present application;

FIG. 6 is a diagram illustrating a phase compensation table according to an embodiment of the present application;

FIG. 7 is a diagram illustrating a format of a calibration signal according to an embodiment of the present application;

fig. 8 is a schematic diagram illustrating a correspondence relationship between a phase compensation table and frequency points according to an embodiment of the present application;

fig. 9 is a schematic diagram illustrating a corresponding relationship between a phase compensation table, frequency points, and temperatures according to an embodiment of the present disclosure;

fig. 10 is a schematic diagram illustrating a flow of a phase compensation method according to an embodiment of the present application;

fig. 11 is a schematic diagram illustrating device shifts of gain devices corresponding to link shifts according to an embodiment of the present application;

fig. 12 is a schematic diagram of a process of determining a downlink equivalent channel matrix by an AP according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of a first AP according to an embodiment of the present application;

fig. 14 is a schematic structural diagram of a second AP according to an embodiment of the present application;

fig. 15 is a schematic structural diagram of a third AP according to an embodiment of the present application.

Detailed Description

The embodiment of the application can be applied to the WLAN, and the adopted standard of the WLAN is IEEE 802.11 series. A WLAN may include one or more Basic Service Sets (BSSs), with network nodes in the basic service set including APs and STAs. Each basic service set may include an AP and a plurality of STAs associated with the AP. The AP may be configured to communicate with the STA via a wireless local area network, and transmit data of the STA to the network side, or transmit data from the network side to the STA.

AP, also known as hotspot. The AP is an access point for a mobile subscriber to enter a wired network, and is mainly deployed in a home, a building, and a campus, and typically has a coverage radius of several tens of meters to hundreds of meters, and may be deployed outdoors. The AP may be a terminal device or a network device with a WLAN chip.

The STA may be a wireless communication chip, a wireless sensor, or a wireless communication terminal. For example: the mobile phone supporting the WLAN communication function, the tablet computer supporting the WLAN communication function, the set top box supporting the WLAN communication function, the smart television supporting the WLAN communication function, the smart wearable device supporting the WLAN communication function, the vehicle-mounted communication device supporting the WLAN communication function and the computer supporting the WLAN communication function.

The system architecture and the application scenario described in the present application are for more clearly illustrating the technical solution of the present application, and do not constitute a limitation to the technical solution provided in the present application, and as a person of ordinary skill in the art knows, along with the evolution of the system architecture and the appearance of a new service scenario, the technical solution provided in the present application is also applicable to similar technical problems.

Fig. 1 is a system diagram of a WLAN deployment scenario, where fig. 1 includes an AP and 3 STAs, and the AP communicates with STA1, STA2, and STA3, respectively, to form a BSS. The devices in the same BSS share the air interface channel, and only one device can transmit data in the air interface channel at a time. Before STA1, STA2, and STA3 transmit data, they need to listen to the air interface channel and contend for the air interface channel when the channel is idle.

The procedure of the AP transmitting signals to the STA through the IBF is described as follows, in conjunction with the schematic diagram shown in fig. 1. Wherein, STA may be any one of STA1, STA2 and STA3 in fig. 1.

As shown in fig. 2, the AP receives radio frequency signals from the STA through a plurality of radio frequency links, and performs channel estimation on an uplink channel according to the radio frequency signals to obtain Channel State Information (CSI) of the channel from the STA to the AP, which is understood as that the AP performs channel estimation on the uplink channel according to the radio frequency signals to obtain an uplink equivalent channel matrix. And the AP determines the transpose matrix of the uplink equivalent channel matrix as the downlink equivalent channel matrix of the channel from the AP to the STA. And the AP generates a pre-coding matrix according to the downlink equivalent channel matrix, BF weighting is carried out on the original baseband signals according to the pre-coding matrix, baseband signals of each radio frequency link are determined, and the radio frequency links process the baseband signals corresponding to each radio frequency link to generate radio frequency signals corresponding to each radio frequency link and send the radio frequency signals to the STA. Here, the uplink equivalent channel matrix may also be referred to as an uplink channel matrix or a channel matrix from the STA to the AP; the downlink equivalent channel matrix may also be referred to as a downlink channel matrix, or an AP-to-STA channel matrix.

Further, LTF fields, such as legacy-long-training field (L-LTF), extreme high-throughput long-training field (EHT-LTF), very high-throughput long-training field (VHT-LTF), high-efficiency long-training field (HE-LTF), and so on, are included in the rf signal. The LTF field is used for the AP to perform channel estimation on the uplink channel.

It should be noted that, radio frequency links exist in both the AP and the STA, and when a gain device in the radio frequency link performs gain amplification on a signal, the signal generates phase jump.

Taking an AP side as an example for illustration, fig. 3 is a schematic structural diagram of a radio frequency link in an AP provided in an embodiment of the present application, and as shown in fig. 3, an AP includes 4 radio frequency links, which are, from top to bottom, a radio frequency link 0, a radio frequency link 1, a radio frequency link 2, and a radio frequency link 3. The structure of each rf chain is the same, and each rf chain includes three stages of gain devices, namely an external low noise amplifier (elana), an internal low noise amplifier (ilan), and a Variable Gain Amplifier (VGA).

The three-stage gain device is used for gain amplification of signals respectively, wherein the eLNA is a first-stage low noise amplifier and has the characteristics of large gain step, good Noise Factor (NF) and the like, and if the eLNA is opened, the eLNA has positive gain of 10dB to 12dB and negative gain of 10 dB. The iLNA is a second-stage low noise amplifier, and if the iLNA can be divided into 8 gears, the difference between every two gears is about 6 dB. The VGA is a third-stage variable gain amplifier, has the characteristics of amplification after down-conversion of analog signals, high adjustable gain precision and the like, and generally can achieve 1dB of gain stepping.

In the three-stage gain device, each gain device can generate different degrees of phase influence on signals. Specifically, when the analog signal passes through each gain device, the radio frequency time delay generates initial phase jump to the signal and phase jump on each subcarrier. For example, before up-conversion, the rf delay of the elan and the ilan causes the initial phase jump of the signal and the phase jump on each subcarrier, while the if delay of the down-converted VGA causes the phase jump of the signal on each subcarrier.

With the k sub-carrierSignal s_k(t) is an example, where s_k(t)＝a(k)e^j2πkΔft. Assuming an amplitude response of 1, signal s_k(t) s output after passing eLNA, iLNA and VGA_k(t)' is shown in formula (1).

In the formula (1), τ_RFThe radio frequency time delay comprises time delays generated by corresponding eLNA and iLNA; tau is_IFThe intermediate frequency delay includes the delay generated by the corresponding VGA.

For ease of understanding, the following takes zero IF circuit as an example, T in equation (1)_IFTo 0, equation (2) is obtained.

Wherein the content of the first and second substances,

indicating that the radio frequency time delay causes initial phase jump of the signal;

indicating that the radio frequency delay results in a phase jump on a subcarrier of the signal.

Further, in the zero if circuit, the input rf signal y (t) is shown in formula (3).

Wherein x (t) x_I(t)+jx_Q(t) is a baseband signal, fourier-expanded x (t) Σ_ka_ke^j2πkΔft。

The output radio frequency signal y (t)' is shown in formula (4).

Wherein the content of the first and second substances,

indicating the radio frequency delay results in a phase jump of the signal on each subcarrier.

In summary, when each gain device in the rf link processes a signal, the rf delay may affect the initial phase of the signal and the phase of each subcarrier, thereby affecting the accuracy of the signal.

Further, since the phase influence of the radio frequency link on the signal when the AP transmits the signal is different from the phase influence of the radio frequency link on the signal when the AP receives the signal, the uplink channel and the downlink channel between the AP and the STA are not completely equivalent.

A reciprocity calibration method is provided for realizing the equivalence of an uplink channel and a downlink channel between an AP and an STA. Since the phase influence of the radio frequency link used for receiving the signal on the STA side on the signal can be balanced and cancelled by the STA side, the reciprocity calibration method is mainly implemented on the AP side.

The reciprocity calibration method may be implemented by the AP sending and receiving calibration signals, which are understood to be radio frequency signals used for reciprocity calibration. Fig. 4 is a schematic diagram of reciprocity calibration performed by an AP according to the present application, and the schematic diagram of the structure of the radio frequency link in the AP may refer to fig. 3, which is not described again.

Taking the example of the reciprocity calibration performed by the AP on the radio frequency link 0, for example, (a) in fig. 4 shows that the radio frequency link 0 transmits radio frequency signals to the radio frequency link 1, the radio frequency link 2, and the radio frequency link 3, respectively, to obtain a calibration result that the radio frequency link 0 serves as a transmitting radio frequency link, for example, (b) in fig. 4 shows that the radio frequency link 0 receives radio frequency signals from the radio frequency link 1, the radio frequency link 2, and the radio frequency link 3, respectively, to obtain a calibration result that the radio frequency link 0 serves as a receiving radio frequency link, and the AP determines the reciprocity compensation value of the radio frequency link 0 based on the two calibration results.

Therefore, the AP can determine the reciprocity compensation value corresponding to each radio frequency link in the AP based on the reciprocity calibration, and then the AP transmits the baseband signal in each radio frequency link to the STA after performing the reciprocity compensation based on the reciprocity compensation value corresponding to each radio frequency link.

However, during the reciprocity calibration, the AP sets the rf link to be in a fixed link gear to receive and process the rf signal. In practical application, since each STA needs to compete for an air interface channel, the signal power of the radio frequency signal received by the AP may change, and the AP automatically adjusts the link gear of the radio frequency link according to the signal power and processes the received radio frequency signal based on the link gear. The fixed link gear adopted by each radio frequency link when the AP performs reciprocity calibration is different from the link gear adopted by each radio frequency link when the AP actually receives signals.

Referring to fig. 1 and 4, each rf link of the AP has 4 link gears, which are a link gear a, a link gear B, a link gear C, and a link gear D. When the AP performs reciprocity calibration on the radio frequency link 0, the AP determines that the radio frequency link 0 is in a fixed link gear A and processes radio frequency signals from a radio frequency link 1, a radio frequency link 2 and a radio frequency link 3; in practical applications, when receiving the rf signal 1 from the STA1, the AP automatically adjusts the rf link 0 to the link gear B according to the signal power of the rf signal 1, or when receiving the rf signal 2 from the STA2, the AP automatically adjusts the rf link 0 to the link gear C according to the signal power of the rf signal 2.

The other radio frequency links are similar, when the AP performs reciprocity calibration on the radio frequency link 1, the AP determines that the radio frequency link 1 is in a fixed link gear B and processes radio frequency signals from the radio frequency link 0, the radio frequency link 2 and the radio frequency link 3; in practical applications, when receiving the rf signal 1 from the STA1, the AP automatically adjusts the rf link 1 to the link gear a according to the signal power of the rf signal 1, or when receiving the rf signal 2 from the STA2, the AP automatically adjusts the rf link 1 to the link gear C according to the signal power of the rf signal 2.

And because the radio frequency links have different phase influences on signals when in different link gears, the fixed link gears adopted by the radio frequency links when the AP performs reciprocity calibration are different from the link gears adopted by the radio frequency links when the AP actually receives the signals, and the signals have phase jump. In this case, when the AP performs reciprocity compensation according to the reciprocity compensation value, the problem of inaccurate compensation occurs, which further causes inequality between the uplink channel and the downlink channel and affects the accuracy of the signal transmitted by each radio frequency link of the AP.

Based on the above problem, the phase calibration method provided in the embodiments of the present application may be executed in an AP, or may be executed in a module (e.g., a chip) applied in the AP. The following description will take an AP and an STA as examples.

The phase calibration method provided by the embodiment of the present application is described below with reference to a flowchart shown in fig. 5.

For convenience of description, a single-device phase compensation value when the AP determines that the first gain device in the first radio frequency link is in the gear to be measured is taken as an example for explanation. The first radio frequency link is any one of a plurality of radio frequency links of the AP, the first radio frequency link comprises at least two gain devices, and the first gain device is any one of the at least two gain devices.

In step 501, the AP processes a first rf signal transmitted by a second rf link with a first rf link in a first state to obtain a first baseband signal.

The AP may perform phase calibration in a self-sending and self-receiving manner, where the AP includes a first radio frequency link and a second radio frequency link, the AP transmits a first radio frequency signal through the second radio frequency link, and the AP receives the first radio frequency signal through the first radio frequency link, that is, the second radio frequency link is a radio frequency link for transmitting a signal, and the first radio frequency link is a radio frequency link for receiving a signal.

Furthermore, the AP may preempt the second radio frequency link to an air interface channel of the first radio frequency signal, and then send the first radio frequency signal to the first radio frequency link through the second radio frequency link via the air interface channel; the AP may also transmit the first rf signal to the first rf link via the internal circuitry via the second rf link.

The AP may set the first radio frequency link to be in a first state, where a receiving gear of a first gain device in the first radio frequency link in the first state is in a gear to be measured, and receiving gears of gain devices other than the first gain device are in respective preset gears. For example, the gain devices in the first radio frequency link are eLNA, iLNA and VGA in sequence, and the preset gears corresponding to the eLNA, the iLNA and the VGA are set to be eLNA gear 0, iLNA gear 1 and VGA gear 1 respectively. Wherein, iLNA is first gain device, and iLNA's gear that awaits measuring is iLNA gear 2. The gears of eLNA, iLNA and VGA are respectively fixed to eLNA gear 0, iLNA gear 2 and VGA gear 1.

In practical application, when the AP receives the first radio frequency signal through the first radio frequency link, it is necessary to automatically adjust a link gear of the first radio frequency link according to a signal power of the first radio frequency signal, that is, to automatically adjust a device gear of each gain device in the first radio frequency link. Therefore, when the AP performs phase calibration, an Automatic Gain Control (AGC) may be used to control each gain device in the first rf link to be in a fixed device gear position to process the first rf signal.

And 502, determining a single-device phase compensation value when the first gain device is in a gear to be measured according to the first baseband signal and the second baseband signal by the AP.

The second baseband signal is obtained by processing a second radio-frequency signal transmitted by a second radio-frequency link of the AP through the first radio-frequency link in the second state, wherein the receiving gears of all gain devices in the first radio-frequency link in the second state are in respective preset gears; and the initial phases of the first radio frequency signal and the second radio frequency signal are the same.

The AP generates the same original baseband signal twice, the original baseband signal for the first time is output as a first radio frequency signal through a second radio frequency link, and the first radio frequency signal is processed through a first radio frequency link in a first state to obtain a first baseband signal; the second original baseband signal is output as a second radio frequency signal through a second radio frequency link, and the second radio frequency signal is processed through the first radio frequency link in a second state to obtain a second baseband signal; the difference between the first radio frequency link in the first state and the first radio frequency link in the second state is only the gear to be tested of the former first gain device, and the preset gear of the latter first gain device. And the AP determines a single-device phase compensation value when the first gain device is in the gear to be measured according to the first baseband signal and the second baseband signal.

And the AP determines a phase compensation value of the single device when the first gain device is in the gear to be measured according to the first baseband signal and the second baseband signal, and at least has the following two implementation modes.

In the first implementation manner, the AP determines a phase compensation value of a single device when the first gain device is in a gear to be measured according to a phase difference between a phase of the first baseband signal and a phase of the second baseband signal.

In the second implementation mode, the AP determines a first phase difference caused by processing the radio frequency signal by the first radio frequency link when the first gain device is at the gear to be measured according to the phase of the first baseband signal and the phase of the original baseband signal; and the AP determines a single-device phase compensation value when the first gain device is in the gear to be measured according to the difference value between the first phase difference and the preset phase difference. The preset phase difference is a phase difference caused by the fact that the first radio frequency link processes the radio frequency signal when the first gain device is in a preset gear according to the phase of the second baseband signal and the phase of the original baseband signal.

Further, the first gain device may include a plurality of device steps, that is, the AP may perform phase calibration for the first gain device for a plurality of times, for example, the first gain device includes 8 device steps, where the device step 0 is a preset step, and the AP may perform phase calibration for the first gain device for 7 times. In order to improve the phase calibration efficiency, the AP may use the second baseband signal obtained when the first gain device is in device gear 0 (the first radio frequency link is in the second state) in any phase calibration when the first gain device is in device gear 1 to device gear 7 (the first radio frequency link is in the first state), respectively.

In the first implementation manner, the AP stores the phase of the second baseband signal in advance in a storage module of the AP, so that the AP may determine the phase compensation value of the single device when the first gain device is in each device gear according to the phase of the first baseband signal and the phase of the second baseband signal stored in advance. In the second implementation manner, the AP prestores the preset phase difference in a storage module of the AP, so that the AP may determine the phase compensation value of the single device when the first gain device is in each device gear according to a difference between the first phase difference and the prestored preset phase difference.

After determining the single-device phase compensation value when the first gain device is in the gear to be measured, the AP may record the single-device phase compensation value in the phase compensation table. The phase compensation table records the phase compensation value of the single device when each gain device in the radio frequency link is in the gear position of each device.

Exemplarily, gain device includes eLNA, iLNA, VGA in the radio frequency link, and wherein, eLNA has 2 eLNA gears, and iLNA has 8 iLNA gears, and VGA has 32 VGA gears, sets up the preset gear of eLNA, iLNA and VGA and is eLNA gear 0, iLNA gear 0 and VGA gear 0 respectively.

The AP determines a single-device phase compensation value when the eLNA is at the eLNA position 1; the iLNA is respectively at a single-device phase compensation value of iLNA gear 1, … …, iLNA gear 6 and iLNA gear 7; the single-component phase compensation values of the VGA are respectively at VGA gear 1 and … …, VGA gear 30 and VGA gear 31; the phase compensation table shown in fig. 6 is finally obtained. It should be noted that when the AP determines the single-device phase compensation value of the gain device, specifically, the AP determines the phase difference between the phase jump generated by the gain device in each device gear and the phase jump generated by the gain device in the preset gear, based on the preset gear of the gain device. It should be understood that the AP need not determine the single device phase compensation value when the gain device is in the preset gear, but it can also be understood that the AP determines the single device phase compensation value of the gain device in the preset gear to be 0.

As in fig. 6, the AP determines that the single-device phase compensation value is 0 when the elina is in the elina range 0; the AP determines that the phase compensation value of the single device is 0 when the iLNA is at the iLNA gear 0; and the AP determines that the phase compensation value of the single device is 0 when the VGA is at the VGA gear 0.

Referring to fig. 6, when the AP determines, for each gain device, a single-device phase compensation value when the AP is in each device shift position (including the AP determining the single-device phase compensation value when each gain device is in each preset shift position), the AP performs 2 phase calibrations on the elan, 8 phase calibrations on the ilan, and 32 phase calibrations on the VGA, then the AP performs 42 phase calibrations in total, and generates 42 single-device phase compensation values. If the AP determines the link phase compensation value when the AP is in each link gear for each radio frequency link, the AP needs to perform 512 phase calibrations and generate 512 phase compensation values for the radio frequency links because the radio frequency links have 512 link gears (2 × 8 × 32 ═ 512).

Therefore, in the phase calibration method, the AP determines the phase compensation value of a single device when the AP is in each device gear for each gain device, and the generated phase compensation table is also for each device gear of each gain device, so that the computation complexity of the AP and the storage size of the phase compensation table in the AP can be reduced by this method.

The first radio frequency signal and the second radio frequency signal can be understood as calibration signals in phase calibration of the AP. Fig. 7 exemplarily shows a format of a calibration signal provided by the present application, where the calibration signal includes a WLAN Legacy field (Legacy field) and a plurality of identical LTFs, where the WLAN Legacy field is in an HE SU frame format, each LTF is generated by using an LTF with a better peak to average power ratio (PAPR), and is an Orthogonal Frequency Division Multiplexing (OFDM) symbol that is identical in a time domain. By the method, the AP performs multi-symbol superposition based on a plurality of same LTFs, and the signal-to-noise ratio is improved.

It should be noted that, because a plurality of radio frequency links in the AP are products in the same batch, that is, the gain devices of the same type in each radio frequency link are products in the same batch, and the phase compensation values of the corresponding single devices when the gain devices of the same type in different radio frequency links are in the shift positions of the devices are almost the same, in order to improve the phase calibration efficiency, the phase compensation value of the single device when each gain device in the radio frequency link is in the shift position of each device may be determined for any one radio frequency link, and may be used in other radio frequency links.

For example, in fig. 3, the AP includes 4 radio frequency links, each radio frequency link includes three gain devices, namely, an elan, an lna and a VGA, the AP determines a single-device phase compensation value when the elan is in each elan shift position, a single-device phase compensation value when the ilan is in each ilan shift position, and a single-device phase compensation value when the VGA is in each VGA shift position in the radio frequency link 0, and applies the single-device phase compensation values to the radio frequency link 1, the radio frequency link 2, and the radio frequency link 3.

In conjunction with the schematic diagram of the structure of the radio frequency link in the AP as shown in fig. 3, the following provides an implementation for determining the phase compensation value of a single device.

The first radio frequency link may be any one of 4 radio frequency links, and the second radio frequency link may be other than the first radio frequency link among the 4 radio frequency links. Gain device includes eLNA, iLNA and VGA in the first radio frequency link, and wherein, eLNA has 2 eLNA gears, and iLNA has 8 iLNA gears, and VGA has 32 VGA gears.

The first gain device is exemplified as the iLNA.

Assume that the preset gears of the eLNA, the iLNA and the VGA are eLNA gear 0, iLNA gear 0 and VGA gear 0, respectively. The single device phase compensation value for the iLNA at each iLNA gear is determined as follows.

The AP broadcasts a control signal (e.g., CTS to SELF), where the control signal is used to preempt an air interface channel, so that the AP may send a first radio frequency signal or a second radio frequency signal to the first radio frequency link through the second radio frequency link.

The AP sets the first radio frequency link to be in the second state, that is, sets the edana, the ilana, and the VGA to be in edana range 0, ilana range 0, and VGA range 0, respectively. The AP generates an original baseband signal, outputs the original baseband signal to be a second radio frequency signal through a second radio frequency link, transmits the second radio frequency signal to the first radio frequency link through an air interface channel, and processes the second radio frequency signal through the first radio frequency link to obtain the second baseband signal.

The AP determines the single device phase compensation value for the iLNA in iLNA range 1. Specifically, the AP sets the first rf link to be in the first state, that is, sets the edana, the lna and the VGA to be in edana range 0, ilana range 1 and VGA range 0, respectively. The AP generates an original baseband signal, outputs the original baseband signal to be a first radio frequency signal through a second radio frequency link, transmits the first radio frequency signal to a first radio frequency link through an air interface channel, and processes the first radio frequency signal through the first radio frequency link to obtain a first baseband signal. The AP determines a single-device phase compensation value (iLNA single-device phase compensation value 1) when the iLNA is in the iLNA range 1, based on the phase of the first baseband signal and the phase of the second baseband signal.

The AP determines the single device phase compensation value for the lna in lna range 2. Specifically, the AP sets the first radio frequency link to be in the first state, that is, sets the edana, the lna and the VGA to be in edana range 0, ilana range 2 and VGA range 0, respectively. The AP generates an original baseband signal, the original baseband signal is output as a first radio frequency signal through the second radio frequency link, the AP transmits the first radio frequency signal to the first radio frequency link through the air interface channel, and the first radio frequency link processes the first radio frequency signal to obtain a first baseband signal. The AP determines a single-device phase compensation value (iLNA single-device phase compensation value 2) when the iLNA is in the iLNA range 2, based on the phase of the first baseband signal and the phase of the second baseband signal.

The AP determines the phase compensation value of the single device when the iLNA is in the iLNA range 3 to the iLNA range 7, and is similar to the phase compensation value of the single device when the AP determines that the iLNA is in the iLNA range 1 or the iLNA range 2, and is not described again.

In addition, when the first gain device is an eLNA, the AP determines a single-device phase compensation value when the eLNA is at each eLNA gear, which is similar to the single-device phase compensation value when the AP determines that the iLNA is at each iLNA gear; when the first gain device is a VGA, the AP determines a single-device phase compensation value when the VGA is at each VGA gear, and the single-device phase compensation value is similar to the single-device phase compensation value when the AP determines that the iLNA is at each iLNA gear; and will not be described in detail.

As above, the phase compensation table shown in fig. 6 can be obtained.

In the embodiment of the application, the preset gear of each gain device can be determined according to the fixed link gear during AP reciprocity calibration. For example, in fig. 4, the fixed link gear during the AP reciprocity calibration is the link gear a, and then the ehna gear 0, the iLNA gear 1, and the VGA gear 1 corresponding to the link gear a are respectively determined as preset gears of the ehna, the iLNA, and the VGA.

It should be noted that when the AP performs reciprocity calibration in different environments, the fixed link gear used by the AP may be different, for example, in environment 1, the AP uses link gear a as the fixed link gear, and in environment 2, the AP uses link gear C as the fixed link gear. Therefore, the fixed link gear during the calibration of the reciprocity of the AP may be temporarily not considered, and the preset gear of each gain element in the AP may be determined according to the actual situation, for example, the eLNA gear 0, the iLNA gear 0, and the VGA gear 0 are directly determined as the preset gear of the eLNA, the iLNA, and the VGA, respectively.

Here, it should be understood that there are two setting modes for the AP, where setting mode 1 is to determine the preset gear of each gain device according to the fixed link gear during the calibration of the reciprocity of the AP, and setting mode 2 is to determine the preset gear of each gain device according to the actual situation. Because the preset gears of the gain devices set by the two gain devices are different, the single-device phase compensation values of the gain devices determined by the two gain devices are also different. Therefore, there is a difference in the way of compensating the AP for phase compensation, and the difference can be referred to the following embodiments in which the AP performs phase compensation.

It can be known from the above embodiments that the phase compensation values of the single devices of the gain device at different device gears are different, and equivalently, the phase compensation value of the single device of the gain device is a function of the gear of the device in which the gain device is located. Further, in the embodiment of the present application, in order to improve the accuracy of the phase compensation value of the single device of the gain device in different device gears, the influence of the working channel frequency point of the gain device on the phase compensation value of the single device of the gain device is considered, that is, in an optional implementation manner, the gear of the device in which the gain device is located and the working channel frequency point are used as variables, and the phase compensation value of the single device of the gain device is a function of the variables.

The AP sets a corresponding phase compensation table for each frequency point. That is to say, when the AP performs phase calibration, a single-device phase compensation value of each gain device in the radio frequency link at each device gear is determined for a specific frequency point of a working channel, and the obtained single-device phase compensation value is recorded in a phase compensation table corresponding to the specific frequency point. The AP may statically store a plurality of phase compensation tables.

For example, the correspondence between the phase compensation table and the frequency point stored in the AP may be as shown in fig. 8. Frequency points for indicating a frequency band, e.g. frequency point f_c1For indicating frequency band (f)_c1－Δf₁，f_c1+Δf₁) Wherein, frequency point f_c1Is a frequency band (f)_c1－Δf₁，f_c1+Δf₁) The center frequency point of (1). The value of each frequency point can be determined empirically, and is not limited herein.

Further, the variable affecting the phase compensation value of the single device in the AP may also include a temperature, that is, a temperature of an environment in which the AP is located. In another optional implementation manner, the gear, the frequency point of the working channel, and the temperature of the device where the gain device is located are used as variables, and the phase compensation value of a single device of the gain device is a function of the variables.

The AP sets a corresponding phase compensation table for each frequency point and each temperature. That is to say, when the AP performs phase calibration, a single-device phase compensation value of each gain device in the radio frequency link at each device gear is determined for a specific frequency point and a specific temperature of a working channel, and the obtained single-device phase compensation value is recorded in a phase compensation table corresponding to the specific frequency point and the specific temperature. The AP may statically store a plurality of phase compensation tables.

The temperature being indicative of a temperature interval, e.g. temperature T₁For indicating the temperature interval (T)₁－ΔT₁，T₁+ΔT₁). Frequency points for indicating a frequency band, e.g. frequency point f_c1For indicating frequency band (f)_c1－Δf₁，f_c1+Δf₁) Wherein, frequency point f_c1Is a frequency band (f)_c1－Δf₁，f_c1+Δf₁) The center frequency point of (1). The value of each frequency point and the value of each temperature can be determined according to experience, and is not limited here.

In addition, it should be noted that, in the phase compensation table corresponding to any frequency point or the phase compensation table corresponding to any frequency point and temperature, the single-device phase compensation value of the gain device in the device gear represents the phase compensation value of the gain device in the device gear with respect to the central frequency point. Let us assume, phase compensation table f_c1-T₁As shown in fig. 6, the phase compensation value 1 of the edlna in fig. 6 is that the edlna is at the edlna gear 1, and the center frequency f is_c1The phase compensation value of (1). Further, as can be seen from the above formula (4),

indicating the radio frequency delay causes an initial phase jump of the signal, i.e. for the signal at the central frequency f_cMay be understood as an initial phase compensation value of the signal.

Based on the technical scheme, the AP determines the phase jump generated when the gain device is in the gear to be measured compared with the gain device in the preset gear according to the first baseband signal and the second baseband signal, and further determines the phase compensation value of the single device when the gain device is in the gear to be measured. The single-device phase compensation value can be used for adjusting an uplink equivalent channel matrix, so that a downlink equivalent channel matrix with higher accuracy is predicted, and the problem of phase jump caused by the difference between a fixed link gear adopted during reciprocity calibration and a link gear automatically adjusted during radio-frequency signal receiving is solved.

In the above, the implementation of the phase calibration performed by the AP is described in detail, and the AP may adjust the uplink equivalent channel matrix from the STA to the AP based on the single-device phase compensation value of each gain device obtained in the phase calibration.

Fig. 10 is a schematic diagram of a flow of a phase compensation method according to an embodiment of the present application, and the flow includes the following flows.

In step 1001, the AP receives radio frequency signals from the STAs via a plurality of radio frequency links.

The AP comprises a plurality of radio frequency links, and when the AP receives radio frequency signals from the STA through each radio frequency link, the AP adjusts each radio frequency link to a corresponding link gear according to the signal power of the radio frequency signals received by each radio frequency link. The AP may adjust each rf link to be in the same link gear to receive the rf signal, or may adjust each rf link to be in a different link gear to receive the rf signal.

Each radio frequency link comprises at least two gain devices, and the link gear of each radio frequency link corresponds to the receiving gear of each gain device in the radio frequency link. Fig. 11 illustrates exemplary device shifts of gain devices corresponding to link shifts, where the gain devices in the radio frequency link include an elana, an lna and a VGA, and exemplary link shift a corresponds to the elana shift 0, the ilana shift 1 and the VGA shift 1; link gear B corresponds eLNA gear 1, iLNA gear 2, VGA gear 4.

Step 1002, the AP measures the radio frequency signal and obtains a downlink equivalent channel matrix of the channel from the AP to the STA according to the plurality of phase compensation values.

Step 1002 may refer to the flowchart shown in fig. 12, and may include the following steps:

step 1201, the AP measures the radio frequency signal to obtain an uplink equivalent channel matrix of the channel from the STA to the AP.

The uplink equivalent channel matrix of the channel from the STA to the AP includes a plurality of row vectors, the plurality of row vectors corresponds to the plurality of radio frequency links one to one, each radio frequency link in the plurality of radio frequency links corresponds to a phase compensation value, and the phase compensation value corresponding to each radio frequency link is used for adjusting the row vector corresponding to the radio frequency link.

Step 1202, the AP determines a phase compensation value of each radio frequency link, and adjusts a row vector corresponding to each radio frequency link in the uplink equivalent channel matrix according to the phase compensation value of each radio frequency link.

For example, the AP receives radio frequency signals through N radio frequency links, and the AP measures the radio frequency signals to obtain an uplink equivalent channel matrix H of a channel from the STA to the AP, where H may refer to formula (5).

The AP determines that the phase compensation values of the N radio frequency links are phase compensation values 1, … … and phase compensation value N, respectively, and adjusts the uplink equivalent channel matrix H according to the phase compensation values 1, … … and the phase compensation value N to obtain adjusted H', which can refer to formula (6).

In step 1202, the AP may determine the phase compensation value of each rf link according to a single-device phase compensation value of each gain device in each rf link.

Taking any one of the radio frequency links as an example, the AP determines the receiving gear of each gain device in the radio frequency link, and determines a single-device phase compensation value when each gain device is in the respective receiving gear from the phase compensation table according to the receiving gear of each gain device; and determining the sum of the single-device phase compensation values of the gain devices as the phase compensation value of the radio frequency link.

In combination with the above example of fig. 6, it is assumed that fig. 6 is a phase compensation table of the AP, the single-device phase compensation value of the elan is a single-device phase compensation value 1 of the elan, the single-device phase compensation value of the ilan is a single-device phase compensation value 2 of the ilan, and the single-device phase compensation value of the VGA is a single-device phase compensation value 4 of the VGA, and then the phase compensation value of the radio frequency link is determined to be the sum of the single-device phase compensation value 1 of the elan, the single-device phase compensation value 2 of the ilan, and the single-device phase compensation value 4 of the VGA.

In practical applications, the phase compensation value of a single device can be expressed in the frequency domain as

Wherein the content of the first and second substances,

for the phase of the gain element in the preset gear,

the phase of the gain device at the test gear is used. In the above example, for example, the single-device phase compensation value of eLNA is

The single-device phase compensation value of iLNA is

Single device phase compensation value of VGA

Determining a phase compensation value for the radio frequency link

Is composed of

And

the sum of the total weight of the components,

as shown in equation (7).

It should be noted that the single-device phase compensation value of the gain device in the above example may refer to a difference between a phase difference caused by the gain device in a preset shift position and a phase difference caused by the gain device in a receive shift position, that is, the AP substantially takes a preset shift position when the AP performs phase calibration as a reference when determining the single-device phase compensation value.

When the AP performs phase calibration, there are two preset gear setting methods (refer to the setting method 1 and the setting method 2), and when the AP performs phase compensation according to the phase compensation tables obtained by different setting methods, there are the following differences:

in the setting mode 1, the preset gear is a device gear of each gain device corresponding to a fixed link gear when the reciprocity of the AP is calibrated, and the AP may determine a single-device phase compensation value of each gain device in the radio frequency link from the phase compensation table, so as to determine a phase compensation value of the radio frequency link.

In the setting mode 2, the preset gear is a device gear of each gain device determined according to actual experience, at this time, the preset gear of each gain device is not necessarily completely consistent with the device gear during the AP reciprocity calibration, and after the AP determines the single-device phase compensation value of each gain device in the radio frequency link from the phase compensation table, the single-device phase compensation value of each gain device needs to be adjusted according to the preset gear of each gain device and the device gear during the AP reciprocity calibration, so as to determine the phase compensation value of the radio frequency link.

Furthermore, as can be seen from the phase calibration process described above, the single-device phase compensation value of the gain device is affected by the variable.

In one implementation, the variables include the operating channel frequency point and the receiving gear of the gain device; and a plurality of phase compensation tables are stored in the AP, and each phase compensation table corresponds to a specific frequency point. Before determining the phase compensation value of the single device when each gain device is in the respective receiving gear, the AP may obtain a phase compensation table corresponding to a working channel frequency point of the gain device, and determine the phase compensation value of the single device when each gain device is in the respective receiving gear from the phase compensation table corresponding to the working channel frequency point.

For example, referring to fig. 8, when the working channel frequency point of the AP is located in the frequency band (f)_c1－Δf₁，f_c1+Δf₁) In, AP obtains phase compensation table f_c1(ii) a When the working channel frequency point of the AP is located in the frequency band (f)_c2－Δf₂，f_c2+Δf₂) In, AP obtains phase compensation table f_c2。

In another implementation mode, the variables comprise working channel frequency points, temperature and receiving gears of the gain device; and a plurality of phase compensation tables are stored in the AP, and each phase compensation table corresponds to a specific frequency point and a specific temperature. Before determining the phase compensation value of the single device when each gain device is in the respective receiving gear, the AP may obtain a phase compensation table corresponding to the temperature at which the gain device is located and the frequency point of the working channel, and determine the phase compensation value of the single device when each gain device is in the respective receiving gear from the phase compensation table corresponding to the current temperature and the frequency point of the working channel.

For example, in conjunction with FIG. 9, when the temperature of the environment in which the AP is located is in the temperature range (T)₁－ΔT₁，T₁+ΔT₁) In the middle, the frequency point of the working channel is located in the frequency band (fc)₁－Δf₁，fc₁+Δf₁) In the middle, AP obtains a phase compensation table fc₁－T₁(ii) a When the temperature of the environment where the AP is located is in the temperature range (T)₂－ΔT₂，T₂+ΔT₂) In the middle, the frequency point of the working channel is located in the frequency band (fc)₂－Δf₂，fc₂+Δf₂) In the middle, AP obtains a phase compensation table fc₂－T₂。

The method fully considers the influence of the receiving gear, the temperature and the working channel frequency point of the gain device on the phase compensation value of the single device, improves the accuracy of the phase compensation value of the single device of the gain device, further improves the accuracy of the phase compensation value of the radio frequency link, and equivalently improves the accuracy of determining the downlink equivalent channel matrix by the AP.

Further, the single-device phase compensation value of the gain device in the phase compensation table at the device gear position can be understood as the phase compensation value of the gain device at the device gear position with respect to the signal at the central frequency point. Therefore, the phase compensation value of the radio frequency link determined by the AP according to the phase compensation table is also a phase compensation value for the signal at the center frequency point, which is equivalent to phase compensation for the signal at the initial phase. Here, the phase compensation value of the radio frequency link determined by the AP according to the phase compensation table may be referred to as an initial phase compensation value of the radio frequency link.

In the embodiment of the present application, the AP may further determine a phase compensation value on each subcarrier, and adjust the uplink equivalent channel matrix of the corresponding subcarrier according to the phase compensation value on each subcarrier, thereby improving the accuracy of the signal transmitted by each radio frequency link of the AP.

In one example, the AP obtains a phase adjustment value of each subcarrier according to a subcarrier to which each uplink equivalent channel matrix belongs; and the AP determines the sum of the initial phase compensation value of the radio frequency link and the phase adjustment value of each subcarrier as the phase compensation value of each subcarrier.

In another example, the AP may determine, according to an initial phase compensation value of the radio frequency link, a radio frequency delay caused by processing the radio frequency signal by the radio frequency link, and further determine, according to the radio frequency delay, a phase compensation value on each subcarrier. For example, as in equation (4), assume that the initial phase compensation value is

Then the radio frequency time delay is determined to be

According to radio-frequency time delay tau_RFDetermining a phase compensation value of the kth subcarrier as

In step 1203, the AP determines the transpose of the uplink equivalent channel matrix of the STA-to-AP channel as the downlink equivalent channel matrix of the AP-to-STA channel.

After determining the downlink equivalent channel matrix, the AP may generate a precoding matrix according to the downlink equivalent channel matrix, and then perform BF weighting according to the precoding matrix to determine the baseband signal of each transmitting radio frequency link. And the AP performs reciprocity compensation on the baseband signals of each transmitting radio frequency link based on the reciprocity compensation value and then sends the baseband signals to the STA.

In the technical scheme, the AP receives radio frequency signals from the STA through each radio frequency link, measures the radio frequency signals to obtain an uplink equivalent channel matrix of a channel from the STA to the AP, determines a downlink equivalent channel matrix of the channel from the AP to the STA according to the uplink equivalent channel matrix and phase compensation values of each radio frequency link, solves the problem of phase jump caused by the difference between a fixed link gear adopted during reciprocity calibration and an automatically adjusted link gear during radio frequency signal receiving, and obtains a downlink equivalent channel matrix with high accuracy. Further, the AP determines a pre-coding matrix according to the downlink equivalent channel matrix, and the AP performs BF weighting on the original baseband signals according to the pre-coding matrix to determine the baseband signals of each radio frequency link. And the AP performs reciprocity compensation on the baseband signals of each transmitting radio frequency link based on the reciprocity compensation value and then sends the baseband signals to the STA, and the BF circuit gain is increased, so that the accuracy of the signals transmitted by each radio frequency link of the AP is improved.

Similar to the above concept, as shown in fig. 13, an AP is further provided in the embodiment of the present application. The AP may be used to implement the steps or processes in the above-described phase compensation method or phase calibration method embodiments.

The AP may include: a communication unit 1301 and a processing unit 1302.

In this embodiment of the application, the communication unit 1301 may also be referred to as a transceiver unit, and may include a transmitting unit and/or a receiving unit, which are respectively configured to perform the steps of AP transmitting and receiving in the foregoing method embodiments.

Illustratively, when the AP implements the functions of the AP in the flow shown in fig. 10:

the communication unit 1301 is configured to receive radio frequency signals from an STA through a plurality of radio frequency links, where each radio frequency link in the plurality of radio frequency links includes at least two gain devices;

the processing unit 1302 is configured to measure the radio frequency signal and obtain a downlink equivalent channel matrix of a channel from the AP to the STA according to a plurality of phase compensation values, where the downlink equivalent channel matrix is a transpose of an uplink equivalent channel matrix of a channel from the STA to the AP, a relationship between the plurality of phase compensation values and the plurality of radio frequency links is a one-to-one correspondence, the uplink equivalent channel matrix includes a plurality of row vectors, a relationship between the plurality of row vectors and the plurality of radio frequency links is a one-to-one correspondence, each row vector of the uplink equivalent channel matrix is adjusted by a phase compensation value of a corresponding radio frequency link, and each phase compensation value of the plurality of phase compensation values is determined based on a sum of phase compensation values of respective single devices of at least two gain devices in the corresponding radio frequency link.

In an alternative implementation, the variable further includes temperature.

Illustratively, when the AP implements the functions of the AP in the flow shown in fig. 5:

the communication unit 1301 is configured to transmit a first radio frequency signal using a second radio frequency link; and receiving a first radio frequency signal with the first radio frequency link;

the processing unit 1302 is configured to process the first radio frequency signal by using a first radio frequency link in a first state to obtain a first baseband signal, where the first radio frequency link includes at least two gain devices, the at least two gain devices include a first gain device, a receiving tap position of the first gain device in the first radio frequency link in the first state is in a to-be-tested tap position, and receiving tap positions of gain devices other than the first gain device are in respective preset tap positions;

the processing unit 1302 is further configured to determine a single device phase compensation value when the first gain device is in a gear to be measured according to the first baseband signal and the second baseband signal; the second baseband signal is obtained by the processing unit 1302 processing a second radio frequency signal transmitted by the second radio frequency link by using the first radio frequency link in a second state, where receiving stages of all gain devices in the first radio frequency link in the second state are in respective preset stages; the initial phases of the first radio frequency signal and the second radio frequency signal are the same.

Similar to the above concept, as shown in fig. 14, an AP is further provided in the embodiments of the present application.

The AP may include: a scheduling module 1401, a compensation module 1402, a calibration module 1403;

the scheduling module 1401 is used for scheduling the compensation module 1402 or the calibration module 1403;

when the compensation module 1402 is scheduled, the AP implements a phase compensation function as the AP in fig. 10; the compensation module 1402 is configured to receive radio frequency signals from STAs via a plurality of radio frequency links; and measuring the radio frequency signal and obtaining a downlink equivalent channel matrix of the channel from the AP to the STA according to a plurality of phase compensation values.

When the scheduling calibration module 1403 is scheduled, the AP implements a phase calibration function as the AP in fig. 5; the calibration module 1403 is configured to process a first radio frequency signal transmitted by a second radio frequency link of the AP with the first radio frequency link in the first state to obtain a first baseband signal; and determining a single-device phase compensation value when the first gain device is in a gear to be measured according to the first baseband signal and the second baseband signal.

Similar to the above concept, as shown in fig. 15, an AP provided in the embodiment of the present application is shown, and the AP shown in fig. 15 may be an implementation manner of a hardware circuit of the AP shown in fig. 13 or fig. 14. The AP may be adapted to perform the functions of the AP in the above method embodiments as illustrated in the flow chart of fig. 5 or as illustrated in fig. 10. For ease of illustration, fig. 15 shows only the main components of the AP.

The AP comprises a processor, a memory and a plurality of radio frequency links;

illustratively, each of the plurality of radio frequency chains may be a receive radio frequency chain or a transmit radio frequency chain.

When the radio frequency link is used as a receiving radio frequency link, the radio frequency link comprises an eLNA, a mixer, an analog-to-digital converter (ADC) and a digital signal processor; when the rf link is used as a transmitting rf link, the rf link includes a PA, a mixer, a digital to analog converter (DAC) and a digital signal processor. The mixer comprises iLNA and VGA.

Illustratively, the receiving radio frequency link may process the received signal by: sequentially adopting eLNA, iLNA and VGA to gain and amplify radio frequency signals received from an antenna; the amplified signal is processed by the ADC and finally by the digital signal processor. The transmit radio frequency link may transmit signals by: the baseband signal is processed by the digital signal processor and then converted into an analog signal by the DAC, the analog signal is up-converted by the mixer into a radio frequency signal, and the radio frequency signal is processed by the PA and then radiated from the antenna.

When the AP performs the flowchart shown in fig. 10, the plurality of rf links may be a plurality of receiving rf links.

Illustratively, the plurality of radio frequency links are configured to receive radio frequency signals from the STA, and each of the plurality of radio frequency links includes at least two gain devices;

In an alternative implementation, the variable further includes a temperature.

When the AP executes the flowchart shown in fig. 5, the multiple rf links may be a transmitting rf link and a receiving rf link, where the transmitting rf link may be a second rf link, and the receiving rf link may be a first rf link.

Illustratively, the second radio frequency link is configured to transmit a first radio frequency signal;

It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, for brevity, details are not repeated here, since the details that are not described in detail may be referred to the above method embodiments.

The present application also provides a computer program product, similar to the above concept, the computer program product comprising: computer program code for implementing the method of any of the embodiments shown in fig. 5 or 10 when the computer program code runs on a computer.

The present application also provides a computer-readable medium storing program code, which when run on a computer, implements the method of any of the embodiments shown in fig. 5 or fig. 10, similar to the above-described concept.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A method of phase compensation, comprising:

an Access Point (AP) receives radio frequency signals from a Station (STA) through a plurality of radio frequency links, wherein each radio frequency link in the plurality of radio frequency links comprises at least two gain devices;

2. The method of claim 1, wherein the single device phase compensation value is a function of variables including frequency bins of the operating channel and receive notch of the corresponding gain device.

3. The method of claim 2, wherein the variable further comprises temperature.

4. A method according to any one of claims 1 to 3, wherein the gain device comprises an external low noise amplifier, an internal low noise amplifier or a variable gain amplifier.

5. The method of any of claims 1 to 4, wherein each of the plurality of phase compensation values is determined based on a sum of single-device phase compensation values for each of at least two gain devices in the corresponding radio frequency link, comprising:

6. A method of phase calibration, comprising:

an Access Point (AP) processes a first radio frequency signal transmitted by a second radio frequency link by using a first radio frequency link in a first state to obtain a first baseband signal, wherein the first radio frequency link comprises at least two gain devices, the at least two gain devices comprise a first gain device, a receiving gear of the first gain device in the first radio frequency link in the first state is in a gear to be tested, and receiving gears of gain devices except the first gain device are in respective preset gears;

7. The method of claim 6, wherein the single device phase compensation value for the first gain device in the gear under test is determined based on a phase difference of the phase of the first baseband signal and the phase of the second baseband signal.

8. The method of claim 6 or 7, wherein the first radio frequency signal or the second radio frequency signal comprises a plurality of identical Long Training Fields (LTFs).

9. An access point, AP, comprising:

a processor, a plurality of radio frequency links;

the radio frequency links are used for receiving radio frequency signals from a station STA, and each radio frequency link in the radio frequency links comprises at least two gain devices;

10. The AP of claim 9, wherein the single device phase compensation value is a function of variables including frequency bins of an operating channel and receive notch of a corresponding gain device.

11. The AP of claim 10, wherein the variable further comprises temperature.

12. The method of any of claims 9 to 11, wherein the gain device comprises an external low noise amplifier, an internal low noise amplifier, or a variable gain amplifier.

13. The AP of any one of claims 9 to 12, wherein each of the plurality of phase compensation values is a sum of single-device phase compensation values of at least two respective gain devices in the corresponding rf link, plus an adjustment value obtained from a subcarrier to which the uplink equivalent channel matrix belongs.

14. An access point, AP, comprising:

15. The AP of claim 14, wherein the single device phase compensation value for the first gain device in the gear under test is determined based on a phase difference of the phase of the first baseband signal and the phase of the second baseband signal.

16. The AP of claim 14 or 15, wherein the first radio frequency signal or the second radio frequency signal comprises a plurality of identical long training fields, LTFs.

17. A computer-readable storage medium, having stored thereon a computer program or instructions, which, when executed, implement the method of any one of claims 1 to 5 or 6 to 8.

18. A computer program product, characterized in that it comprises a computer program or instructions which, when executed, implement the method according to any one of claims 1 to 5 or 6 to 8.