CN103428125A

CN103428125A - Method, related device and system for correcting channels among far-end radio frequency units

Info

Publication number: CN103428125A
Application number: CN2013103608086A
Authority: CN
Inventors: 张超超; 易雄书; 刘云; 陈卫民
Original assignee: Shanghai Huawei Technologies Co Ltd
Current assignee: Shanghai Huawei Technologies Co Ltd
Priority date: 2013-08-16
Filing date: 2013-08-16
Publication date: 2013-12-04

Abstract

An embodiment of the invention discloses a method, a related device and a system for correcting channels among far-end radio frequency units. The method for correcting the channels among the far-end radio frequency units comprises the steps of respectively transmitting correcting signals on M transmitting channels of N far-end radio frequency units, wherein working frequency points of the M transmitting channels are identical to working frequency points of correcting receiving channels; receiving the correcting signals which are transmitted by on the M transmitting channels and looped back by the correcting receiving channels; respectively calculating time delay compensation factors of the M transmitting channels according to the received correcting signals which are transmitted by on the M transmitting channels and looped back by the correcting receiving channels; respectively performing channel correction to the M transmitting channels according to the time delay compensation factors of the M transmitting channels so as to enable time delay of the M transmitting channels to be identical. By means of the technical scheme, the time delay consistency of the transmitting channels (and/or receiving channels) of multiple far-end radio frequency units can be achieved.

Description

Method, related device and system for correcting channels between remote radio units

Technical Field

The present invention relates to the field of communications, and in particular, to a method, a related device, and a system for calibrating channels between remote radio units.

Background

In a Frequency Division Duplex (FDD) system of Long Term Evolution (LTE), a data transmission mode of Closed-Loop multiplexing Input-Output (CL-MIMO) is introduced, in this transmission mode, a terminal selects a Precoding Matrix Indicator (PMI) according to a certain criterion, and reports the PMI to a Base Station (BS), and the BS selects a corresponding precoding matrix to weight downlink transmission data according to the PMI reported by the terminal, thereby achieving the optimal throughput of the system.

In CL-MIMO transmission, a transmitter may employ a 2T2R (i.e., two transmit channels and two receive channels) structure or a 4T4R (i.e., 4 transmit channels and 4 receive channels) structure, and in an LTE network already in commercial use, a 2T2R structure is mostly employed. If a 4T4R structure is needed as the market demand goes deeper, there are two schemes, one is to directly replace the existing 2T2R RRU with a Remote Radio Unit (RRU) of 4T4R, and the other is to use two RRUs to double-pin into one RRU of 4T 4R. For the first scheme, the 2T2R RRU is replaced, and the implementation of the scheme is limited by the high cost factor of the 4T4R RRU, and for the second scheme, since the delay difference between the channels of different RRUs may be large and unstable, which may cause the degradation of CL-MIMO performance, channel correction between different RRUs needs to be performed to keep the delay between the channels of different RRUs consistent.

Coordinated multipoint transmission (CoMP) is a key characteristic of LTE, and the CoMP technology can effectively combat the interference problem at the edge of an LTE cell. Joint Transmission (JT) technology, which is one of CoMP technologies, can significantly improve cell edge and average throughput. In order to realize the gain due to JT technology in a Frequency Division Duplex (FDD) system, channel correction is also required. From this perspective, channel correction needs to be performed among all RRUs in the CoMP cell.

In the prior art, only a channel correction method for a single RRU in an FDD mode exists, and a channel correction scheme between RRUs is not found for a while. Since the channel correction of a single RRU cannot achieve the consistency of the channel delay of the RRU in the case of double-joint, the consistency of the channel delay cannot be achieved in a coordinated multi-Point (CoMP) scenario, which may affect the system performance of CL-MIMO or CoMP.

Disclosure of Invention

The embodiment of the invention provides a method, a related device and a system for correcting channels among a plurality of remote radio frequency units, which are used for realizing the consistency of channel time delay of the plurality of remote radio frequency units.

In order to solve the above technical problems, embodiments of the present invention provide the following technical solutions:

a first aspect of the present invention provides a method for correcting a channel between remote radio units, which is applied in a communication system including N remote radio units, where at least one of the N remote radio units includes a correction reception channel, and the method includes:

transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively, wherein the working frequency points of the M transmitting channels are the same as the working frequency points of the correction receiving channels, the N is more than 1, and the M is more than 1;

receiving the correction signals transmitted on the M transmitting channels looped back by the correction receiving channel;

respectively calculating the time delay compensation coefficients of the M transmitting channels according to the received correction signals which are transmitted on the M transmitting channels and looped back by the correction receiving channel;

and respectively carrying out channel correction on the M transmitting channels according to the time delay compensation coefficients of the M transmitting channels so as to enable the time delays among the M transmitting channels to be consistent.

Based on the first aspect of the present invention, in a first possible implementation manner, the calculating delay compensation coefficients of the M transmission channels according to the received calibration signals, which are looped back by the calibration receiving channel and transmitted on the M transmission channels, includes:

according to the received correction signals which are sent on the M sending channels and looped back by the correction receiving channel, carrying out channel estimation on the M sending channels to obtain channel response values of the M sending channels;

respectively calculating the time delay difference between each transmitting channel and a reference transmitting channel according to the channel response values of the M transmitting channels, wherein the reference transmitting channel is one of the M transmitting channels;

and respectively taking the time delay difference between each transmitting channel and the reference transmitting channel obtained by calculation as a time delay compensation coefficient of each transmitting channel.

Based on the first possible implementation manner of the first aspect of the present invention, in a second possible implementation manner, the calculating, according to the channel response values of the M transmission channels, a delay difference between each transmission channel and the reference transmission channel respectively includes:

respectively calculating the phase difference between each transmitting channel and the reference transmitting channel on a frequency domain according to the channel response values of the M transmitting channels;

and calculating the time delay difference between each transmitting channel and the reference transmitting channel according to the phase difference between each transmitting channel and the reference transmitting channel.

Based on the first aspect of the present invention, or the first possible implementation manner of the first aspect of the present invention, or the second possible implementation manner of the first aspect of the present invention, in a third possible implementation manner, the transmitting correction signals on the M transmission channels of the N remote radio frequency units respectively specifically includes:

transmitting correction signals on the M transmitting channels of the N remote radio frequency units respectively in a frequency division mode;

or,

and transmitting the correction signals on the M transmitting channels of the N remote radio frequency units respectively by adopting a code division mode.

A second aspect of the present invention provides a method for correcting a channel between remote radio units, which is applied in a communication system including N remote radio units, where at least one of the N remote radio units includes a correction transmission channel, and the method for correcting the channel includes:

transmitting a calibration signal in the calibration transmit channel;

receiving a calibration signal transmitted on the calibration transmitting channel looped back by the M receiving channels of the N remote radio frequency units, wherein the working frequency points of the M receiving channels are the same as the working frequency points of the calibration transmitting channel, N is greater than 1, and M is greater than 1;

respectively calculating the time delay compensation coefficients of the M receiving channels according to the received correction signals which are transmitted on the correction transmitting channel and looped back by the M receiving channels;

and respectively carrying out channel correction on the M receiving channels according to the time delay compensation coefficients of the M receiving channels so as to enable the time delays among the M receiving channels to be consistent.

Based on the second aspect of the present invention, in a first possible implementation manner, the calculating delay compensation coefficients of the M receiving channels according to the received calibration signals transmitted on the calibration transmitting channel looped back by the M receiving channels includes:

according to the received correction signal which is sent by the correction sending channel and looped back by the M receiving channels, carrying out channel estimation on the M receiving channels to obtain channel response values of the M receiving channels;

respectively calculating the time delay difference between each receiving channel and a reference receiving channel according to the channel response values of the M receiving channels, wherein the reference receiving channel is one of the M receiving channels;

and respectively taking the calculated time delay difference between each receiving channel and the reference receiving channel as the time delay compensation coefficient of each receiving channel.

Based on the first possible implementation manner of the second aspect of the present invention, in a second possible implementation manner, the calculating, according to the channel response values of the M receiving channels, a delay difference between each receiving channel and the reference receiving channel includes:

calculating the phase difference between each receiving channel and the reference receiving channel on a frequency domain according to the channel response values of the M receiving channels;

and calculating the time delay difference between each receiving channel and the reference receiving channel according to the phase difference between each receiving channel and the reference receiving channel.

A third aspect of the present invention provides a channel calibration apparatus applied in a communication system including N remote rf units, where at least one of the N remote rf units includes a calibration receiving channel, the channel calibration apparatus including:

a transmitting unit, configured to transmit calibration signals on M transmitting channels of the N remote radio frequency units, respectively, where working frequency points of the M transmitting channels are the same as working frequency points of the calibration receiving channel, where N is greater than 1, and M is greater than 1;

a receiving unit, configured to receive the calibration signals sent on the M sending channels looped back by the calibration receiving channel;

a calculating unit, configured to calculate delay compensation coefficients of the M transmitting channels according to the calibration signals transmitted on the M transmitting channels, which are looped back by the calibration receiving channel and received by the receiving unit;

and the channel correction unit is used for respectively carrying out channel correction on the M transmitting channels according to the time delay compensation coefficients of the M transmitting channels so as to enable the time delays among the M transmitting channels to be consistent.

Based on the third aspect of the present invention, in a first possible implementation manner, the calculating unit includes:

a first sub-calculating unit, configured to perform channel estimation on the M transmitting channels according to the calibration signals transmitted on the M transmitting channels, which are looped back by the calibration receiving channel and received by the receiving unit, to obtain channel response values of the M transmitting channels;

a second sub-calculating unit, configured to calculate, according to the channel response values of the M transmitting channels calculated by the first sub-calculating unit, a time delay difference between each transmitting channel and a reference transmitting channel, where the reference transmitting channel is one of the M transmitting channels;

the calculating unit uses the delay differences between the transmitting channels and the reference transmitting channel calculated by the second sub-calculating unit as the delay compensation coefficients of the transmitting channels respectively.

Based on the first possible implementation manner of the third aspect of the present invention, in a second possible implementation manner, the second sub-calculating unit is specifically configured to: respectively calculating the phase difference between each transmitting channel and the reference transmitting channel on a frequency domain according to the channel response values of the M transmitting channels; and calculating the time delay difference between each transmitting channel and the reference transmitting channel according to the phase difference between each transmitting channel and the reference transmitting channel.

Based on the third aspect of the present invention, or the first possible implementation manner of the third aspect of the present invention, or the second possible implementation manner of the third aspect of the present invention, in a third possible implementation manner, the transmitting unit is specifically configured to: and respectively transmitting the correction signals on the M transmitting channels of the N remote radio frequency units by adopting a frequency division mode or a code division mode.

A fourth aspect of the present invention provides a channel calibration apparatus, applied in a communication system including N remote rf units, where at least one of the N remote rf units includes a calibration transmission channel, the channel calibration apparatus including:

a transmitting unit for transmitting a correction signal in the correction transmitting channel;

a receiving unit, configured to receive a calibration signal transmitted on the calibration transmitting channel looped back by M receiving channels of the N remote radio frequency units, where working frequency points of the M receiving channels are the same as those of the calibration transmitting channel, where N is greater than 1, and M is greater than 1;

a calculating unit, configured to calculate delay compensation coefficients of the M receiving channels according to the calibration signals transmitted on the calibration transmitting channel, which are looped back by the M receiving channels and received by the receiving unit;

and the channel correction unit is used for respectively carrying out channel correction on the M receiving channels according to the time delay compensation coefficients of the M receiving channels calculated by the calculation unit so as to enable the time delays among the M receiving channels to be consistent.

Based on the fourth aspect of the present invention, in a first possible implementation manner, the calculating unit includes:

a first sub-calculating unit, configured to perform channel estimation on the M receiving channels according to the calibration signals sent by the calibration sending channel and looped back by the M receiving channels received by the receiving unit, so as to obtain channel response values of the M receiving channels;

a second sub-calculating unit, configured to calculate, according to the channel response values of the M receiving channels calculated by the first sub-calculating unit, a time delay difference between each receiving channel and a reference receiving channel, where the reference receiving channel is one of the M receiving channels;

the calculating unit uses the delay differences between the receiving channels and the reference receiving channel calculated by the second sub-calculating unit as the delay compensation coefficients of the transmitting channels.

Based on the first possible implementation manner of the fourth aspect of the present invention, in a second possible implementation manner, the second sub-calculating unit is specifically configured to: calculating the phase difference between each receiving channel and the reference receiving channel on a frequency domain according to the channel response values of the M receiving channels; and calculating the time delay difference between each receiving channel and the reference receiving channel according to the phase difference between each receiving channel and the reference receiving channel.

A fifth aspect of the present invention provides a channel correction system, including:

the system comprises N remote radio frequency units, a first channel correction device connected with the N remote radio frequency units, and a second channel correction device connected with the N remote radio frequency units;

wherein, in the N remote rf units, at least one remote rf unit includes a calibration receiving channel, and at least one remote rf unit includes a calibration transmitting channel;

the first channel calibration device is configured to: transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively, wherein the working frequency points of the M transmitting channels are the same as the working frequency points of the correction receiving channels, the N is more than 1, and the M is more than 1; receiving the correction signals transmitted on the M transmitting channels looped back by the correction receiving channel; respectively calculating the time delay compensation coefficients of the M transmitting channels according to the received correction signals which are transmitted on the M transmitting channels and looped back by the correction receiving channel; respectively carrying out channel correction on the M transmitting channels according to the time delay compensation coefficients of the M transmitting channels so as to enable the time delays among the M transmitting channels to be consistent;

the second channel calibration device is configured to: transmitting a calibration signal in the calibration transmit channel; receiving a calibration signal transmitted on the calibration transmitting channel looped back by the M receiving channels of the N remote radio frequency units, wherein the working frequency points of the M receiving channels are the same as the working frequency points of the calibration transmitting channel; respectively calculating the time delay compensation coefficients of the M receiving channels according to the received correction signals which are transmitted on the correction transmitting channel and looped back by the M receiving channels; and respectively carrying out channel correction on the M receiving channels according to the time delay compensation coefficients of the M receiving channels so as to enable the time delays among the M receiving channels to be consistent.

As can be seen from the above, in the embodiment of the present invention, by setting the calibration receiving channel (and/or the calibration transmitting channel), and making the operating frequency point of the calibration receiving channel identical to the operating frequency point of the transmitting channel of the RRU (and/or making the operating frequency point of the calibration transmitting channel identical to the operating frequency point of the receiving channel of the RRU), so that the calibration receiving channel can loop back the calibration signals transmitted on the transmission channels of different RRUs, calculating the time delay compensation coefficients of the transmitting channels of different RRUs according to the looped correction signals (and/or enabling the receiving channels of different RRUs to loop back the correction signals transmitted in the correction transmitting channels, calculating the time delay compensation coefficients of the receiving channels of different RRUs according to the looped correction signals), realizing the channel correction of the transmitting channels (and/or the receiving channels) among different RRUs, thereby realizing the time delay consistency of the transmitting channels (and/or the receiving channels) of the remote radio frequency units.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic flow chart illustrating an embodiment of a channel calibration method according to the present invention;

FIG. 2 is a schematic flow chart illustrating a channel calibration method according to another embodiment of the present invention;

fig. 3 is a schematic structural diagram of an embodiment of an RRU dual-radio communication system provided in the present invention;

FIG. 4 is a schematic structural diagram of an embodiment of a channel calibration device according to the present invention;

FIG. 5 is a schematic structural diagram of another embodiment of a channel calibration device according to the present invention;

fig. 6 is a schematic structural diagram of an embodiment of a channel calibration system according to the present invention.

Detailed Description

The embodiment of the invention provides a method, a related device and a system for correcting channels among remote radio frequency units.

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A method for correcting a channel between Remote Radio Units (RRUs) in the embodiment of the present invention is described below by taking correction of a transmission channel between RRUs as an example. The channel correction method in the embodiment of the present invention is applied to a communication system including N RRUs, and at least one RRU includes a correction reception channel in the communication system including the N RRUs, as shown in fig. 1, the channel correction method in the embodiment of the present invention includes:

101. respectively transmitting correction signals on M transmission channels of N RRUs;

the working frequency points of the M transmitting channels are the same as the working frequency points of the correcting receiving channel, wherein N is more than 1, and M is more than 1.

In the embodiment of the present invention, a channel correction device is respectively connected to N RRUs, each RRU includes a transmission channel, and the channel correction device respectively transmits a correction signal on M transmission channels of the N RRUs, where the M transmission channels may be all transmission channels included in the N RRUs, for example, if there are 3 RRUs and each RRU includes 2 transmission channels, then the 3 RRUs include 6 transmission channels in total, then M may be equal to 6, and the channel correction device respectively transmits a correction signal on the 6 transmission channels; or, the M transmission channels may only include the transmission channel that needs to be channel corrected, and in the above example, assuming that only 4 of 6 transmission channels included in 3 RRUs need to be channel corrected, M is equal to 4, and the channel correcting apparatus respectively transmits the correction signal on the 4 transmission channels.

In the embodiment of the present invention, the channel calibration apparatus may respectively transmit the calibration signals on the M transmission channels by using a frequency division method, a code division method, or other methods, where the calibration signals transmitted by the channel calibration apparatus on the M transmission channels may be the same or different, and the calibration signals may be, for example, Common Reference Signals (CRS) or other redesigned calibration signals with excellent characteristics, which is not limited herein.

102. Receiving the correction signals transmitted on the M transmitting channels looped back by the correction receiving channel;

in the embodiment of the invention, the channel correction device is connected with the correction receiving channel, because the working frequency point of the correction receiving channel is the same as that of the transmitting channel, the correction signals transmitted by the channel correction device on the M transmitting channels are looped back to the correction receiving channel through the air interfaces between the antennas, and the correction receiving channel feeds the received correction signals to the channel correction device. For example, it is assumed that in step 101, the channel correction device transmits correction signals on 4 transmission channels, which are respectively assumed to be s₁，s₂，s₃And s₄At this time, the channel is correctedThe device receives 4 correction signals looped back by the correction receiving channel, and due to channel fading and other reasons in the transmission process, the 4 correction signals received by the channel correction device and the 4 correction signals transmitted before are different, that is, the 4 correction signals received by the channel correction device at this time are s₁’，s₂’，s₃' and s₄’。

103. Respectively calculating the time delay compensation coefficients of the M transmitting channels according to the received correction signals which are transmitted on the M transmitting channels and looped back by the correction receiving channel;

in this embodiment of the present invention, the channel calibration apparatus may perform channel estimation on the M transmission channels according to the calibration signal looped back by the calibration receiving channel received in step 102, to obtain channel response values of the M transmission channels, then calculate time delay differences between each transmission channel and a reference transmission channel in a frequency domain or a time domain according to the channel response values of the M transmission channels, and use the calculated time delay differences between each transmission channel and the reference transmission channel as time delay compensation coefficients of each transmission channel, respectively, where the reference transmission channel is one of the M transmission channels, and in step 103, the time delay compensation coefficient of the reference transmission channel is 1. In this embodiment of the present invention, one transmission channel may be determined from the M transmission channels as a reference transmission channel according to a certain principle, for example, one transmission channel may be determined from the M transmission channels as a reference transmission channel according to a minimum time delay principle, or one transmission channel may be randomly determined from the M transmission channels as a reference transmission channel, which is not limited herein.

When the channel correction device calculates the time delay difference between each emission channel and the reference emission channel on the frequency domain according to the channel response values of the M emission channels, the channel correction device firstly calculates the phase difference between each emission channel and the reference emission channel on the frequency domain according to the channel response values of the M emission channels, and then calculates the phase difference between each emission channel and the reference emission channel according to the phase-delay conversion formula and the time delay conversion formulaAnd calculating the phase difference between each transmitting channel and the reference transmitting channel, and calculating the time delay difference between each transmitting channel and the reference transmitting channel. For example, assume that in step 101, the channel calibration device transmits calibration signals s on the transmission channels 1-4 respectively₁，s₂，s₃And s₄The channel correction means receives a correction signal s in step 102₁’，s₂’，s₃' and s₄', wherein, s₁Is' s₁Signal s looped back through antenna null between transmitting channel 1 and correcting receiving channel₂Is' s₂Signal s looped back through antenna null between transmitting channel 2 and correcting receiving channel₃Is' s₃Signal s looped back through antenna air interface between transmitting channel 3 and correcting receiving channel₄Is' s₄And (3) the signal looped back through the air interface of the antenna between the transmitting channel 4 and the correcting receiving channel. The channel calibration device first performs channel estimation on the transmission channels 1-4 according to the calibration signal received from step 102, for example, conjugate multiplication is performed on the received calibration signal and the calibration signal transmitted on the corresponding channel (i.e. s is multiplied by s)₁' and s₁Performing conjugate multiplication on s₂' and s₂Carrying out conjugate multiplication, s₃' and s₃Carrying out conjugate multiplication, s₄' and s₄Conjugate multiplication) is carried out, Least Square (LS) estimation of channel response of each transmitting channel is obtained, and then channel response values of 1-4 transmitting channels are obtained through processing such as noise reduction. Taking an LTE system as an example, assuming that h (1, k) represents a channel response value of a k-th subcarrier of a transmission channel 1, h (2, k) represents a channel response value of a k-th subcarrier of a transmission channel 2, h (3, k) represents a channel response value of a k-th subcarrier of a transmission channel 3, h (4, k) represents a channel response value of a k-th subcarrier of a transmission channel 4, and the transmission channel 1 is taken as a reference transmission channel, h (2, k) and h (1, k) are subjected to conjugate multiplication to obtain a phase difference Δ θ between the transmission channel 2 and the subcarrier of the transmission channel 1, where the subcarrier of the transmission channel 1 is k₂(k) Then an equivalent delta theta is calculated over all sub-carriers₂By analogy, h (3, k)And h (1, k) are subjected to conjugate multiplication to obtain a phase difference delta theta of the subcarrier k on the transmitting channel 3 and the transmitting channel 1₃(k) Then an equivalent delta theta is calculated over all sub-carriers₃Conjugate multiplication processing is carried out on h (4, k) and h (1, k) to obtain the phase difference delta theta of the subcarrier with k on the transmitting channel 4 and the transmitting channel 1₄(k) Then an equivalent delta theta is calculated over all sub-carriers₄. Finally according to delta theta₂，△θ₃And Δ θ₄And conversion formula of phase and time delay

The time delay difference delta tau between the emission channel 2 and the emission channel 1 can be obtained₂Delay difference delta tau between emission channel 3 and emission channel 1₃Delay difference delta tau between emission channel 4 and emission channel 1₄Wherein in the formula

Where f denotes the frequency domain width of the subcarrier, and then Δ τ₂，△τ₃And Δ τ₄Respectively as the delay compensation coefficients of the transmitting channel 2, the transmitting channel 3 and the transmitting channel 4, and the delay compensation coefficient of the transmitting channel 1 is 1.

When the channel correction device calculates the time delay difference between each emission channel and the reference emission channel according to the channel response values of the M emission channels in the time domain, the channel correction device converts the channel response values of the M emission channels into the time domain through Fourier transformation, and then calculates the time delay difference between each emission channel and the reference emission channel in the time domain. For example, assume that in step 101, the channel calibration device transmits calibration signals s on the transmission channels 1-4 respectively₁，s₂，s₃And s₄The channel correction means receives a correction signal s in step 102₁’，s₂’，s₃' and s₄', wherein, s₁Is' s₁Signal s looped back through antenna null between transmitting channel 1 and correcting receiving channel₂Is' s₂Through the transmission channel 2 and the calibrationReceiving signals s of aerial empty loop between channels₃Is' s₃Signal s looped back through antenna air interface between transmitting channel 3 and correcting receiving channel₄Is' s₄And (3) the signal looped back through the air interface of the antenna between the transmitting channel 4 and the correcting receiving channel. The channel calibration device first performs channel estimation on the transmission channels 1-4 according to the calibration signal received from step 102, for example, conjugate multiplication of the received calibration signal and the calibration signal transmitted on the corresponding transmission channel (i.e. s is multiplied by s)₁' and s₁Conjugate multiplication is carried out, s 2' and s2 are conjugate multiplied, and s₃' and s₃Carrying out conjugate multiplication, s₄' and s₄Conjugate multiplication is carried out) to obtain Least Square (LS, Least Square) estimation of channel response of each transmitting channel, then noise reduction and other processing are carried out to obtain channel response values of transmitting channels 1-4, assuming that h (1, k) represents the channel response value of the kth subcarrier of the transmitting channel 1, h (2, k) represents the channel response value of the kth subcarrier of the transmitting channel 2, h (3, k) represents the channel response value of the kth subcarrier of the transmitting channel 3, h (4, k) represents the channel response value of the kth subcarrier of the transmitting channel 4, the transmitting channel 1 is taken as a reference transmitting channel, a channel correcting device converts h (1, k), h (2, k), h (3, k) and h (4, k) into time domains through Fourier transformation, and respectively records as h (1, n), h (2, n), h (3, n) and h (4, n), wherein n represents a time domain sampling point, then a maximum module value is searched on h (1, n), and a time domain nutrient point corresponding to the maximum module value is taken as a time delay tau of the emission channel 1₁Searching the maximum module value on h (2, n), and taking the time domain sample point corresponding to the maximum module value as the time delay tau of the transmitting channel 2₂Searching the maximum module value on h (3, n), and taking the time domain sample point corresponding to the maximum module value as the time delay tau of the transmitting channel 3₃Searching the maximum module value on h (4, n), and taking the time domain sample point corresponding to the maximum module value as the time delay delta tau of the transmitting channel 4₃Will tau be₂And τ₁Subtracting to obtain the time delay difference delta tau between the emission channel 2 and the emission channel 1₂Will tau be₃And τ₁Subtracting to obtain the time of the transmitting channel 3 and the transmitting channel 1Delay delta tau₃Will be Δ τ₃And τ₁Subtracting to obtain the time delay difference delta theta between the transmitting channel 4 and the transmitting channel 1₄After that, Δ τ is added₂，△τ₃And Δ τ₄Respectively as the delay compensation coefficients of the transmitting channel 2, the transmitting channel 3 and the transmitting channel 4, and the delay compensation coefficient of the transmitting channel 1 is 1.

104. Respectively carrying out channel correction on the M transmitting channels according to the time delay compensation coefficients of the M transmitting channels so as to enable the time delays among the M transmitting channels to be consistent;

in this embodiment of the present invention, after obtaining the delay compensation coefficient, the channel correction device may perform channel correction on the M transmission channels in a time domain, or may also perform channel correction on the M transmission channels in a frequency domain, which is not limited herein.

For example, assume that the delay compensation coefficient of the jth transmit channel of the ith RRU calculated in step 103 is β_i,jThen, performing channel correction on the jth transmit channel of the ith RRU may be recorded as:

wherein h is_i,jRepresenting the frequency domain response of the jth transmit channel of the ith RRU before channel correction,

and representing the frequency domain response of the j transmission channel of the ith RRU after channel correction.

It should be noted that the channel correction method in the embodiment of the present invention may be applied to an FDD system, a CoMP system, or another communication system using multiple RRUs, and the channel correction device in the embodiment of the present invention may be a baseband processing Unit (BBU), or a device independent of the BBU, which is not limited herein.

As can be seen from the above, in the embodiment of the present invention, by setting the calibration receiving channel and making the working frequency point of the calibration receiving channel the same as the working frequency point of the transmission channel of the RRU, the calibration receiving channel can loop back the calibration signal transmitted in the transmission channels of different RRUs, and calculate the delay compensation coefficients of the transmission channels of different RRUs according to the looped back calibration signal, thereby implementing the channel calibration of the transmission channels between different RRUs, and implementing the transmission channel delay consistency of multiple remote radio units.

A method for correcting a channel between remote radio units (i.e., RRUs) in the embodiment of the present invention is described below by taking correction of a receiving channel between RRUs as an example. The channel correction method in the embodiment of the present invention is applied to a communication system including N RRUs, and at least one RRU includes a correction transmission channel in the communication system including the N RRUs, as shown in fig. 2, the channel correction method in the embodiment of the present invention includes:

201. transmitting a calibration signal in the calibration transmit channel;

in the embodiment of the invention, the channel correction device is respectively connected with N RRUs, each RRU comprises a receiving channel, wherein at least one RRU comprises a correction sending channel, and the channel correction device transmits a correction signal in the correction sending channel.

In the embodiment of the present invention, the calibration Signal may be, for example, a Sounding RS (whose parameters may be configured from a baseband) or a demodulation Reference Signal (DMRS) Signal generated by a User Equipment (UE) as the calibration Signal, or other calibration signals with excellent characteristics may be designed, which is not limited herein.

202. Receiving the correction signals transmitted on the correction transmitting channel looped back by the M receiving channels of the N RRUs;

the working frequency points of the M receiving channels are the same as the working frequency points of the correction transmitting channel, wherein N is more than 1, and M is more than 1.

Examples of the inventionBecause the working frequency point of the correction transmitting channel is the same as the working frequency points of the M receiving channels, the correction signal transmitted by the channel correction device on the correction transmitting channel loops back to the M receiving channels through the air interfaces between the antennas, and the M receiving channels respectively feed the received correction signal to the channel correction device. For example, assuming that M is equal to 4, in step 101, the channel calibration apparatus transmits a calibration signal on the calibration transmitting channel, assuming s, and due to the channel difference of each receiving channel, the receiving of the calibration signal looped back by the 4 receiving channels by the channel calibration apparatus will be different, i.e. the receiving of the calibration signal by the channel calibration apparatus will be s at this time₁’，s₂’，s₃' and s₄’。

203. Respectively calculating the time delay compensation coefficients of the M receiving channels according to the received correction signals which are transmitted on the correction transmitting channel and looped back by the M receiving channels;

in this embodiment of the present invention, the channel calibration apparatus may perform channel estimation on the M receiving channels according to the calibration signal looped back by the M receiving channels received in step 202, to obtain channel response values of the M receiving channels, then calculate a delay difference between each receiving channel and a reference receiving channel in a frequency domain or a time domain according to the channel response values of the M receiving channels, and use the calculated delay difference between each receiving channel and the reference receiving channel as a delay compensation coefficient of each receiving channel, respectively, where the reference receiving channel is one of the M receiving channels, and in step 203, the delay compensation coefficient of the reference receiving channel is 1. In this embodiment of the present invention, one receiving channel may be determined from the M receiving channels as a reference receiving channel according to a certain principle, for example, one receiving channel may be determined from the M receiving channels as a reference receiving channel according to a principle of minimum time delay, or one receiving channel may be randomly determined from the M receiving channels as a reference receiving channel, which is not limited herein.

When the channel correction device calculates the delay difference between each receiving channel and the reference receiving channel on the frequency domain according to the channel response values of the M receiving channels, the channel correction device firstly calculates the phase difference between each receiving channel and the reference receiving channel on the frequency domain according to the channel response values of the M receiving channels, and then calculates the delay difference between each receiving channel and the reference receiving channel according to the phase-to-delay conversion formula and the calculated phase difference between each receiving channel and the reference receiving channel. For example, assume that in step 201, the channel correction apparatus transmits a correction signal s on the correction transmission channel, and the channel correction apparatus receives the correction signal s in step 202₁’，s₂’，s₃' and s₄', wherein, s₁Is s a signal looped back through an antenna air interface between the correction transmitting channel and the receiving channel 1, s₂Is s a signal looped back through the antenna air interface between the correction transmitting channel and the receiving channel 2, s₃Is s a signal looped back through the antenna air interface between the correction transmitting channel and the receiving channel 3, s₄' is the signal that s loops back through the antenna air interface between the calibration transmit channel and the receive channel 4. The channel calibration device first performs channel estimation on the receiving channels 1-4 according to the calibration signal received in step 202, for example, conjugate-multiplying the received calibration signal with the calibration signal transmitted in the calibration transmitting channel (i.e., s is₁'conjugate multiplication with s, conjugate multiplication of s 2' with s, s₃' conjugate multiplication with s, s₄Conjugate multiplication is carried out on the channel response values g (1, k) and g (2, k) and g (1, k) respectively to obtain a channel response value of each receiving channel 1-4, then the channel response value of the kth subcarrier of the receiving channel 1 and the channel response value of the kth subcarrier of the receiving channel 2 are obtained by noise reduction and other processing, g (2, k) represents the channel response value of the kth subcarrier of the receiving channel 2, g (3, k) represents the channel response value of the kth subcarrier of the receiving channel 3, g (4, k) represents the channel response value of the kth subcarrier of the receiving channel 4, the receiving channel 1 is taken as a reference receiving channel, and the conjugate multiplication processing is carried out on g (2, k) and g (1, k) to obtain the receiving channel 2 and the subcarrier on the receiving channel 1Phase difference Δ θ of wave k₂(k) Then an equivalent delta theta is calculated over all sub-carriers₂And by analogy, conjugate multiplication processing is carried out on g (3, k) and g (1, k) to obtain the phase difference delta theta of the subcarrier k on the receiving channel 3 and the receiving channel 1₃(k) Then an equivalent delta theta is calculated over all sub-carriers₃Conjugate multiplication processing is carried out on g (4, k) and g (1, k) to obtain the phase difference delta theta of the subcarrier with k on the receiving channel 4 and the receiving channel 1₄(k) Then an equivalent delta theta is calculated over all sub-carriers₄. Finally according to delta theta₂，△θ₃(k) And Δ θ₄And conversion formula of phase and time delay

The time delay difference delta tau between the receiving channel 2 and the receiving channel 1 can be obtained₂Delay difference delta tau between receiving channel 3 and receiving channel 1₃Delay difference delta tau between receiving channel 4 and receiving channel 1₄Wherein in the formula

Where f denotes the frequency domain width of the subcarrier, and then Δ τ₂，△τ₃And Δ τ₄The delay compensation coefficients of the receiving channel 2, the receiving channel 3 and the receiving channel 4 are respectively 1.

When the channel correction device calculates the time delay difference between each receiving channel and the reference receiving channel according to the channel response values of the M receiving channels in the time domain, the channel correction device converts the channel response values of the M receiving channels into the time domain through Fourier transformation, and then calculates the time delay difference between each receiving channel and the reference receiving channel in the time domain. For example, assume that in step 201, the channel correction apparatus transmits a correction signal s on the correction transmission channel, and the channel correction apparatus receives the correction signal s in step 202₁’，s₂’，s₃' and s₄', wherein, s₁Is s signal looped through antenna air interface between correction transmitting channel and receiving channel 1，s₂Is s a signal looped back through the antenna air interface between the correction transmitting channel and the receiving channel 2, s₃Is s a signal looped back through the antenna air interface between the correction transmitting channel and the receiving channel 3, s₄' is the signal that s loops back through the antenna air interface between the calibration transmit channel and the receive channel 4. The channel calibration device first performs channel estimation on the receiving channels 1-4 according to the calibration signal received in step 202, for example, conjugate-multiplying the received calibration signal with the calibration signal transmitted in the calibration transmitting channel (i.e., s is₁' conjugate multiplication with s, and₂' conjugate multiplication with s, s₃' conjugate multiplication with s, s₄' conjugate multiplication with s), obtaining a Least Square (LS, Least Square) estimation of a channel response of each receiving channel, then obtaining channel response values of receiving channels 1-4 by processing of noise reduction and the like, assuming that g (1, k) represents a channel response value of a k-th subcarrier of the receiving channel 1, g (2, k) represents a channel response value of a k-th subcarrier of the receiving channel 2, g (3, k) represents a channel response value of a k-th subcarrier of the receiving channel 3, g (4, k) represents a channel response value of a k-th subcarrier of the receiving channel 4, taking the receiving channel 1 as a reference receiving channel, and a channel correcting device transforms g (1, k), g (2, k), g (3, k) and g (4, k) to a time domain by Fourier transform, and respectively records as g (1, n), g (2, n), g (3, n) and g (4, n), where n represents a time domain sample point, then searching the maximum module value on g (1, n), and using the time domain service point corresponding to the maximum module value as the time delay tau of the receiving channel 1₁Searching the maximum module value on g (2, n), and taking the time domain sample point corresponding to the maximum module value as the time delay tau of the receiving channel 2₂Searching the maximum module value on g (3, n), and taking the time domain sample point corresponding to the maximum module value as the time delay tau of the receiving channel 3₃Searching the maximum module value on g (4, n), and taking the time domain sample point corresponding to the maximum module value as the time delay tau of the receiving channel 4₄Will tau be₂And τ₁Subtracting to obtain the time delay difference delta tau between the receiving channel 2 and the receiving channel 1₂Will tau be₃And τ₁Subtracting to obtain the time delay difference delta tau between the receiving channel 3 and the receiving channel 1₃Will be Δ τ₃And τ₁Subtracting to obtain the time delay difference delta tau between the receiving channel 4 and the receiving channel 1₄After that, Δ τ is added₂，△τ₃And Δ τ₄The delay compensation coefficients of the receiving channel 2, the receiving channel 3 and the receiving channel 4 are respectively 1.

204. Respectively carrying out channel correction on the M receiving channels according to the time delay compensation coefficients of the M receiving channels so as to enable the time delays among the M receiving channels to be consistent;

for example, assume that the delay compensation coefficient of the jth receiving channel of the ith RRU calculated in step 203 is α_i,jThen, performing channel correction on the jth receiving channel of the ith RRU may be recorded as:

wherein h is_i,jRepresenting the frequency domain response of the jth receive channel of the ith RRU before channel correction,

and representing the frequency domain response of the j receiving channel of the i RRU after channel correction.

It should be noted that the channel correction method in the embodiment of the present invention may be applied to an FDD system, a CoMP system, or another communication system using multiple RRUs, and the channel correction apparatus in the embodiment of the present invention may be a BBU, or an apparatus independent of the BBU, which is not limited herein.

As can be seen from the above, in the embodiment of the present invention, by setting the calibration transmitting channel and making the working frequency point of the calibration transmitting channel the same as the working frequency point of the receiving channel of the RRU, the receiving channel of the RRU can loop back the calibration signal transmitted in the calibration transmitting channel, and calculate the delay compensation coefficients of the receiving channels of different RRUs according to the looped back calibration signal, thereby implementing channel calibration of the receiving channels between different RRUs, and implementing the delay consistency of the receiving channels of multiple remote radio units.

As shown in fig. 3, which is an RRU dual-patch communication system applying the channel correction method according to the embodiment of the present invention, the BBU is respectively connected to an RRU0 and an RRU1, and the RRU0 includes two transmission channels (respectively denoted as two transmission channels)

And

) And two receive channels (respectively denoted asAnd

) The RRU1 includes two transmit channels (denoted as respective channels)

And

) And two receive channels (respectively denoted asAnd

) A correction channel (denoted as

) And a calibration receiver channel (denoted as

），

And

is connected to the antenna 1 and is,

and

is connected to the antenna 2 and is,

andis connected to the antenna 3 and is,

andis connected to the antenna 4 and is,

and

connected to the antenna 5.

As shown in fig. 4, a channel correction apparatus 400 in an embodiment of the present invention is described below, where the channel correction apparatus is applied to a communication system including N RRUs, where at least one RRU includes a correction reception channel in the N RRUs, and includes:

a transmitting unit 401, configured to transmit correction signals on M transmitting channels of the N RRUs, respectively, where working frequency points of the M transmitting channels are the same as working frequency points of the correction receiving channel, where N is greater than 1, and M is greater than 1;

in this embodiment of the present invention, the transmitting unit 401 may respectively transmit the correction signals on the M transmitting channels of the N RRUs in a frequency division manner, a code division manner, or in another manner, and the correction signals transmitted by the transmitting unit 401 on the M transmitting channels may be the same or different, where the correction signals may be, for example, Common Reference Signals (CRS) or other redesigned correction signals with excellent characteristics, which is not limited herein.

A receiving unit 402, configured to receive the calibration signals looped back by the calibration receiving channel and transmitted on the M transmitting channels.

A calculating unit 403, configured to calculate delay compensation coefficients of the M transmitting channels respectively according to the calibration signals transmitted on the M transmitting channels looped back by the calibration receiving channel received by the receiving unit 402.

A channel correcting unit 404, configured to perform channel correction on the M transmission channels respectively according to the delay compensation coefficients of the M transmission channels calculated by the calculating unit 403, so that the delays of the M transmission channels are consistent.

In an application scenario, the calculating unit 403 specifically includes: a first sub-calculation unit and a second sub-calculation unit. Wherein the first sub-calculation unit is configured to: performing channel estimation on the M transmitting channels according to the calibration signals transmitted on the M transmitting channels looped back by the calibration receiving channel received by the receiving unit 402, to obtain channel response values of the M transmitting channels; the second sub-calculation unit is used for: calculating the delay difference between each transmission channel and the reference transmission channel according to the channel response values of the M transmission channels calculated by the first sub-calculation unit, wherein the reference transmission channel is one of the M transmission channels; the calculating unit 403 uses the delay differences between the transmitting channels and the reference transmitting channel calculated by the second sub-calculating unit as the delay compensation coefficients of the transmitting channels. In an implementation manner, the second sub-calculation unit is specifically configured to: respectively calculating the phase difference between each transmitting channel and the reference transmitting channel on a frequency domain according to the channel response values of the M transmitting channels; and calculating the time delay difference between each transmitting channel and the reference transmitting channel according to the phase difference between each transmitting channel and the reference transmitting channel. Of course, in another implementation manner, the second sub-calculation unit may also calculate, according to the channel response values of the M transmission channels, the time delay difference between each transmission channel and the reference transmission channel in a time domain, which is not limited herein.

It should be noted that, the channel correction apparatus 400 in the embodiment of the present invention may be the channel correction apparatus in the above method embodiment, and may be used to implement all technical solutions in the above method embodiment, and the specific implementation process may refer to the related description in the above method embodiment, and is not described herein again. The channel correction device in the embodiment of the present invention may be applied to an FDD system, a CoMP system, or another communication system using multiple RRUs, and the channel correction device in the embodiment of the present invention may be a Base Band Unit (BBU) or a device independent of the BBU, which is not limited herein.

As can be seen from the above, in the embodiment of the present invention, by setting the calibration receiving channel and making the working frequency point of the calibration receiving channel the same as the working frequency point of the transmission channel of the RRU, the calibration receiving channel can loop back the calibration signal transmitted in the transmission channels of different RRUs, and calculate the delay compensation coefficients of the transmission channels of different RRUs according to the looped back calibration signal, thereby implementing channel calibration of the transmission channels between different RRUs, and implementing the delay consistency of the transmission channels of multiple RRUs.

An embodiment of the present invention also provides a computer storage medium, where the computer storage medium stores a program that executes a part or all of the arrangements including the channel correction method described in the above-described method embodiment.

An embodiment of the present invention provides another channel correction apparatus, which is applied to a communication system including N RRUs, where at least one RRU includes a correction reception channel in the N RRUs, as shown in fig. 5, the channel correction apparatus 500 in the embodiment of the present invention includes:

an input device 501, an output device 502, a memory 503, and a processor 504 (the number of processors 504 of the channel correction device may be one or more, and fig. 5 takes one processor as an example). In some embodiments of the present invention, the input device 501, the output device 502, the memory 503, and the processor 504 may be connected by a bus or other means, such as the bus connection shown in fig. 5.

Wherein, the processor 504 executes the following steps:

respectively transmitting correction signals on M transmitting channels of the N RRUs, wherein the working frequency points of the M transmitting channels are the same as the working frequency points of the correction receiving channels, N is more than 1, and M is more than 1;

It should be noted that, the channel correction apparatus 500 in the embodiment of the present invention may be the channel correction apparatus in the above method embodiment, and may be used to implement all technical solutions in the above method embodiment, and the specific implementation process may refer to the related description in the above method embodiment, and is not described herein again. The channel correction device in the embodiment of the present invention may be applied to an FDD system, a CoMP system, or another communication system using multiple RRUs, and the channel correction device in the embodiment of the present invention may be a BBU or a device independent of the BBU, which is not limited herein.

A further channel correction apparatus in the embodiment of the present invention is described below, where the channel correction apparatus is applied to a communication system including N RRUs, where at least one RRU in the N RRUs includes a correction transmission channel, and a schematic structural diagram of the channel correction apparatus may be shown in fig. 4, and includes:

in the embodiment of the present invention, the correction signal may simulate, for example, the UE to generate Sounding RS (whose parameters may be configured from a baseband) or DMRS signal as the correction signal, or may design other correction signals with excellent characteristics, which is not limited herein.

And a receiving unit, configured to receive a calibration signal transmitted on the calibration transmitting channel and looped back by M receiving channels of the N RRUs, where working frequency points of the M receiving channels are the same as those of the calibration transmitting channel, N >1, and M > 1.

And a calculating unit, configured to calculate delay compensation coefficients of the M receiving channels according to the calibration signals transmitted on the calibration transmitting channel, which are looped back by the M receiving channels and received by the receiving unit.

And a channel correction unit, configured to perform channel correction on the M receiving channels respectively according to the delay compensation coefficients of the M receiving channels calculated by the calculation unit, so that the delays of the M receiving channels are consistent.

In an application scenario, the computing unit specifically includes: a first sub-calculation unit and a second sub-calculation unit. Wherein the first sub-calculation unit is configured to: according to the correction signal transmitted on the correction transmitting channel looped back by the M receiving channels received by the receiving unit, performing channel estimation on the M receiving channels to obtain channel response values of the M receiving channels; the second sub-calculation unit is used for: calculating the delay difference between each receiving channel and a reference receiving channel according to the channel response values of the M receiving channels calculated by the first sub-calculating unit, wherein the reference receiving channel is one of the M receiving channels; the calculating unit uses the delay differences between the receiving channels and the reference receiving channel calculated by the second sub-calculating unit as the delay compensation coefficients of the transmitting channels. In an implementation manner, the second sub-calculation unit is specifically configured to: calculating the phase difference between each receiving channel and the reference receiving channel on a frequency domain according to the channel response values of the M receiving channels; and calculating the time delay difference between each receiving channel and the reference receiving channel according to the phase difference between each receiving channel and the reference receiving channel. Of course, in another implementation manner, the second sub-calculation unit may also calculate, according to the channel response values of the M receiving channels, the time delay difference between each transmitting channel and the reference transmitting channel in a time domain, which is not limited herein.

It should be noted that, the channel correction device in the embodiment of the present invention may be the channel correction device in the above method embodiment, and may be used to implement all technical solutions in the above method embodiment, and a specific implementation process of the channel correction device may refer to relevant descriptions in the above method embodiment, and is not described herein again. The channel correction device in the embodiment of the present invention may be applied to an FDD system, a CoMP system, or another communication system using multiple RRUs, and the channel correction device in the embodiment of the present invention may be a BBU or a device independent of the BBU, which is not limited herein.

As can be seen from the above, in the embodiment of the present invention, by setting the calibration transmitting channel and making the working frequency point of the calibration transmitting channel the same as the working frequency point of the receiving channel of the RRU, the receiving channels of different RRUs can loop back the calibration signal transmitted in the calibration transmitting channel, and the delay compensation coefficients of the receiving channels of different RRUs are calculated according to the looped back calibration signal, thereby implementing channel calibration of the receiving channels between different RRUs, and implementing the delay consistency of the receiving channels of multiple RRUs.

An embodiment of the present invention provides another channel correction apparatus, where the channel correction apparatus is applied to a communication system including N RRUs, where at least one RRU in the N RRUs includes a correction transmission channel, and a schematic structural diagram of the channel correction apparatus may be shown in fig. 5, and includes:

input device, output device, memory and processor. In some embodiments of the invention, the input device, the output device, the memory, and the processor may be connected by a bus or other means.

The processor in the embodiment of the invention executes the following steps:

transmitting a calibration signal in the calibration transmit channel;

receiving a calibration signal transmitted on the calibration transmitting channel looped back by the M receiving channels of the N RRUs, wherein the working frequency points of the M receiving channels are the same as the working frequency points of the calibration transmitting channel, where N is greater than 1, and M is greater than 1;

As can be seen from the above, in the embodiment of the present invention, by setting the calibration transmitting channel and making the working frequency point of the calibration transmitting channel the same as the working frequency point of the receiving channel of the RRU, the receiving channels of different RRUs can loop back the calibration signal transmitted in the calibration transmitting channel, and calculate the delay compensation coefficients of the receiving channels of different RRUs according to the looped back calibration signal, thereby implementing channel calibration of the receiving channels between different RRUs, and implementing the delay consistency of the receiving channels of multiple RRUs.

An embodiment of the present invention further provides a channel correction system, as shown in fig. 6, a channel correction system 600 in the embodiment of the present invention includes:

n RRUs (e.g., RRU6011 through RRU601N in fig. 6), a first channel correction apparatus 602 connected to the N RRUs, and a second channel correction apparatus 603 connected to the N RRUs; among the N RRUs, at least one RRU includes a calibration receiving channel, and at least one RRU includes a calibration transmitting channel.

A first channel correction device 602, configured to: respectively transmitting correction signals on M transmission channels of the N RRUs, wherein the working frequency points of the M transmission channels are the same as the working frequency points of the correction receiving channels, the N is more than 1, and the M is more than 1; receiving the correction signals transmitted on the M transmitting channels looped back by the correction receiving channel; respectively calculating the time delay compensation coefficients of the M transmitting channels according to the received correction signals which are transmitted on the M transmitting channels and looped back by the correction receiving channel; respectively carrying out channel correction on the M transmitting channels according to the time delay compensation coefficients of the M transmitting channels so as to enable the time delays among the M transmitting channels to be consistent;

second channel correction means 603 for: transmitting a calibration signal in the calibration transmit channel; receiving a calibration signal transmitted on the calibration transmitting channel looped back by the M receiving channels of the N RRUs, wherein the working frequency points of the M receiving channels are the same as the working frequency points of the calibration transmitting channel; respectively calculating the time delay compensation coefficients of the M receiving channels according to the received correction signals which are transmitted on the correction transmitting channel and looped back by the M receiving channels; and respectively carrying out channel correction on the M receiving channels according to the time delay compensation coefficients of the M receiving channels so as to enable the time delays among the M receiving channels to be consistent.

It should be noted that, in the embodiment of the present invention, the first channel correction device 602 and the second channel correction device 603 may be the channel correction device in the above method embodiment, and may be used to implement all technical solutions in the above method embodiment, and a specific implementation process thereof may refer to relevant descriptions in the above method embodiment, and is not described herein again.

As can be seen from the above, in the embodiment of the present invention, by setting the calibration receiving channel and the calibration transmitting channel, and making the working frequency point of the calibration receiving channel the same as the working frequency point of the transmitting channel of the RRU, and making the working frequency point of the calibration transmitting channel the same as the working frequency point of the receiving channel of the RRU, the calibration receiving channel can loop back the calibration signals transmitted in the transmitting channels of different RRUs, and calculate the delay compensation coefficients of the transmitting channels and the receiving channels of different RRUs according to the looped-back calibration signals, so that the channel calibration of the transmitting channels and the receiving channels between different RRUs is realized, and the consistency of the delays of the transmitting channels and the receiving channels of a plurality of remote radio units is realized.

It should be noted that, for the sake of simplicity, the above-mentioned method embodiments are described as a series of acts or combinations, but those skilled in the art should understand that the present invention is not limited by the described order of acts, as some steps may be performed in other orders or simultaneously according to the present invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no acts or modules are necessarily required of the invention.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

Those skilled in the art will appreciate that all or part of the steps of the various methods in the above embodiments may be implemented by associated hardware instructed by a program, which may be stored in a computer-readable storage medium, which may include, for example: read-only memory, random access memory, magnetic or optical disk, and the like.

The above detailed description is provided for the channel calibration method between remote radio units, related apparatus and system, and a specific example is applied in this document to illustrate the principle and embodiment mode of the present invention, and the description of the above embodiment is only used to help understanding the method and core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the embodiment of the present invention, the specific implementation manner and the application range may be changed, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A channel calibration method between remote radio units is applied to a communication system comprising N remote radio units, and is characterized in that at least one remote radio unit in the N remote radio units comprises a calibration receiving channel, and the channel calibration method comprises the following steps:

transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively, wherein working frequency points of the M transmitting channels are the same as working frequency points of the correction receiving channels, N is more than 1, and M is more than 1;

2. The method of claim 1,

the calculating the delay compensation coefficients of the M transmitting channels according to the received calibration signals transmitted on the M transmitting channels looped back by the calibration receiving channel includes:

according to the received correction signals which are sent on the M sending channels and looped back by the correction receiving channels, carrying out channel estimation on the M sending channels to obtain channel response values of the M sending channels;

and respectively taking the time delay difference of each transmitting channel and the reference transmitting channel obtained by calculation as a time delay compensation coefficient of each transmitting channel.

3. The method of claim 2,

the calculating the time delay difference between each transmission channel and the reference transmission channel according to the channel response values of the M transmission channels includes:

4. The method according to any one of claims 1 to 3,

the transmitting correction signals on the M transmitting channels of the N remote rf units respectively specifically includes:

transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively in a frequency division mode;

or,

and transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively in a code division mode.

5. A channel calibration method between remote radio units is applied to a communication system comprising N remote radio units, and is characterized in that at least one remote radio unit in the N remote radio units comprises a calibration transmitting channel, and the channel calibration method comprises the following steps:

transmitting a correction signal at the correction transmit channel;

receiving a calibration signal transmitted on the calibration transmitting channel and looped back by M receiving channels of the N remote radio frequency units, wherein the working frequency points of the M receiving channels are the same as the working frequency points of the calibration transmitting channel, N is greater than 1, and M is greater than 1;

6. The method of claim 5,

the calculating the delay compensation coefficients of the M receiving channels according to the received calibration signals transmitted on the calibration transmitting channel looped back by the M receiving channels includes:

according to the received correction signals which are sent on the correction sending channel and looped back by the M receiving channels, channel estimation is carried out on the M receiving channels, and channel response values of the M receiving channels are obtained;

7. The method of claim 6,

the calculating the delay difference between each receiving channel and the reference receiving channel according to the channel response values of the M receiving channels includes:

respectively calculating the phase difference between each receiving channel and the reference receiving channel on a frequency domain according to the channel response values of the M receiving channels;

8. A channel calibration apparatus applied in a communication system including N remote rf units, wherein at least one of the N remote rf units includes a calibration receiving channel, the channel calibration apparatus comprising:

the transmitting unit is used for transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively, wherein the working frequency points of the M transmitting channels are the same as the working frequency points of the correction receiving channels, N is greater than 1, and M is greater than 1;

a calculating unit, configured to calculate delay compensation coefficients of the M transmitting channels according to the calibration signals transmitted on the M transmitting channels, which are received by the receiving unit and looped back by the calibration receiving channel, respectively;

9. The channel correction apparatus as claimed in claim 8,

the calculation unit includes:

a first sub-calculation unit, configured to perform channel estimation on the M transmission channels according to the correction signals sent on the M transmission channels and received by the receiving unit, where the correction signals are looped back by the correction reception channel, so as to obtain channel response values of the M transmission channels;

a second sub-calculation unit, configured to calculate, according to the channel response values of the M transmission channels calculated by the first sub-calculation unit, a time delay difference between each transmission channel and a reference transmission channel, where the reference transmission channel is one of the M transmission channels;

and the calculating unit is used for respectively taking the time delay difference between each transmitting channel and the reference transmitting channel, which is calculated by the second sub-calculating unit, as the time delay compensation coefficient of each transmitting channel.

10. The channel correction apparatus as claimed in claim 9,

the second sub-calculation unit is specifically configured to: respectively calculating the phase difference between each transmitting channel and the reference transmitting channel on a frequency domain according to the channel response values of the M transmitting channels; and calculating the time delay difference between each transmitting channel and the reference transmitting channel according to the phase difference between each transmitting channel and the reference transmitting channel.

11. The channel correction apparatus according to any one of claims 8 to 10,

the transmitting unit is specifically configured to: and respectively transmitting correction signals on the M transmitting channels of the N remote radio frequency units in a frequency division mode or a code division mode.

12. A channel calibration apparatus for a communication system including N remote rf units, wherein at least one of the N remote rf units includes a calibration transmit channel, the channel calibration apparatus comprising:

a transmitting unit for transmitting a correction signal at the correction transmitting channel;

a receiving unit, configured to receive a calibration signal transmitted on the calibration transmitting channel and looped back by M receiving channels of the N remote radio frequency units, where working frequency points of the M receiving channels are the same as those of the calibration transmitting channel, where N is greater than 1, and M is greater than 1;

13. The channel correction apparatus as claimed in claim 12,

the calculation unit includes:

a first sub-calculation unit, configured to perform channel estimation on the M receiving channels according to the calibration signals sent on the calibration sending channel and looped back by the M receiving channels, where the calibration signals are received by the receiving unit, so as to obtain channel response values of the M receiving channels;

a second sub-calculation unit, configured to calculate, according to the channel response values of the M receiving channels calculated by the first sub-calculation unit, a time delay difference between each receiving channel and a reference receiving channel, where the reference receiving channel is one of the M receiving channels;

and the calculating unit is used for respectively taking the time delay difference between each receiving channel and the reference receiving channel, which is calculated by the second sub-calculating unit, as the time delay compensation coefficient of each transmitting channel.

14. The channel correction apparatus as claimed in claim 13,

the second sub-calculation unit is specifically configured to: respectively calculating the phase difference between each receiving channel and the reference receiving channel on a frequency domain according to the channel response values of the M receiving channels; and calculating the time delay difference between each receiving channel and the reference receiving channel according to the phase difference between each receiving channel and the reference receiving channel.

15. A channel correction system, comprising:

wherein, in the N remote radio frequency units, at least one remote radio frequency unit comprises a correction receiving channel, and at least one remote radio frequency unit comprises a correction transmitting channel;

the first channel correction device is configured to: transmitting correction signals on M transmitting channels of the N remote radio frequency units respectively, wherein working frequency points of the M transmitting channels are the same as working frequency points of the correction receiving channels, N is more than 1, and M is more than 1; receiving the correction signals transmitted on the M transmitting channels looped back by the correction receiving channel; respectively calculating the time delay compensation coefficients of the M transmitting channels according to the received correction signals which are transmitted on the M transmitting channels and looped back by the correction receiving channel; respectively carrying out channel correction on the M transmitting channels according to the time delay compensation coefficients of the M transmitting channels so as to enable the time delays among the M transmitting channels to be consistent;

the second channel correction device is configured to: transmitting a correction signal at the correction transmit channel; receiving a calibration signal transmitted on the calibration transmitting channel looped back by M receiving channels of the N remote radio frequency units, wherein the working frequency points of the M receiving channels are the same as the working frequency points of the calibration transmitting channel; respectively calculating the time delay compensation coefficients of the M receiving channels according to the received correction signals which are transmitted on the correction transmitting channel and looped back by the M receiving channels; and respectively carrying out channel correction on the M receiving channels according to the time delay compensation coefficients of the M receiving channels so as to enable the time delays among the M receiving channels to be consistent.