CN106411372B - Wireless communication method, macro base station and micro base station - Google Patents

Wireless communication method, macro base station and micro base station Download PDF

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CN106411372B
CN106411372B CN201510466747.0A CN201510466747A CN106411372B CN 106411372 B CN106411372 B CN 106411372B CN 201510466747 A CN201510466747 A CN 201510466747A CN 106411372 B CN106411372 B CN 106411372B
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base station
micro base
uplink
kth
matrix
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CN106411372A (en
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徐剑标
夏欣
张伟
易雄书
吕磊
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0636—Feedback format
    • H04B7/0639—Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/32—Hierarchical cell structures

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The embodiment of the invention provides a wireless communication method, a macro base station and a micro base station, wherein after the macro base station obtains a precoding matrix, a downlink physical channel matrix of a kth micro base station is determined, a pre-cancellation weight of a downlink channel of the kth micro base station is obtained according to the downlink physical channel matrix of the kth micro base station, finally, the pre-cancellation weight and an uplink precoding matrix of the downlink channel are used for precoding downlink pilot signals and then sending the downlink pilot signals to the kth micro base station, the kth micro base station obtains a downlink equivalent channel matrix through channel estimation, the downlink equivalent channel matrix is determined as an uplink precoding matrix of the kth micro base station, and uplink precoding is carried out according to the uplink precoding matrix. Because the uplink precoding matrix acquired by the micro base station is not quantized, the micro base station can acquire the high-precision uplink precoding matrix, so that the uplink precoding matrix can be optimally matched with an uplink channel, and the capacity of the uplink channel is improved.

Description

Wireless communication method, macro base station and micro base station
Technical Field
The embodiment of the invention relates to a communication technology, in particular to a wireless communication method, a macro base station and a micro base station.
Background
The increasing user speed demand of mobile broadband networks makes Macro-micro networking become a trend, the Macro-micro networking covers a networking mode through a Macro Base Station (Macro Base Station) and a micro Base Station (Pico Base Station), the micro Base Station is also called a small Base Station, and the micro Base Station is used for performing blind spot, hot spot capacity and coverage enhancement. The macro base station and the micro base station may communicate using a wired backhaul connection and/or a wireless backhaul connection.
In a wireless backhaul communication uplink, Multiple-input Multiple-Output (MIMO) technology is generally adopted to improve spectrum utilization. In the related technology, a macro base station performs channel estimation according to an uplink pilot signal sent by a micro base station to obtain an uplink physical channel Matrix, then traverses a predefined Precoding code quantization codebook set according to the uplink physical channel Matrix by using a cost criterion such as capacity maximization to obtain a Precoding quantization codebook, sends a Precoding Matrix Indicator (PMI) to the micro base station in a downlink channel in a signaling mode, and the micro base station selects a corresponding Precoding Matrix from the Precoding quantization codebook according to the PMI and performs uplink Precoding according to the Precoding Matrix.
In the related art, due to a precoding mechanism based on a codebook, interference is introduced due to quantization of a precoding quantization codebook, so that uplink precoding precision is limited, and the codebook cannot be matched with an optimal channel, thereby reducing uplink capacity.
Disclosure of Invention
The embodiment of the invention provides a wireless communication method, a macro base station and a micro base station, wherein the macro base station can send a high-precision uplink precoding matrix to the micro base station, so that the uplink precoding matrix can be optimally matched with an uplink channel, and the capacity of the uplink channel is improved.
The first aspect of the present invention provides a wireless communication method, including:
a macro base station receives uplink pilot signals respectively sent by N micro base stations, wherein N is a positive integer greater than or equal to 2;
the macro base station determines an uplink physical channel matrix of a kth micro base station according to a received uplink pilot signal sent by the kth micro base station, wherein the value of k is 1, 2, … …, N;
the macro base station determines uplink precoding matrixes of the N micro base stations according to the uplink physical channel matrixes of the N micro base stations;
the macro base station determines a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station;
the macro base station obtains a pre-cancellation weight value of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station;
the macro base station uses the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and then sends the pre-coded downlink pilot signal to the kth micro base station, the pre-cancellation weight of the downlink channel of the kth micro base station and the downlink physical channel matrix of the kth micro base station are cancelled out through pre-coding, and the downlink pilot signal received by the kth micro base station only comprises the uplink pre-coding matrix of the kth micro base station.
With reference to the first aspect, in a first possible implementation manner of the first aspect, the method further includes:
the macro base station receives an uplink signal sent by the kth micro base station, wherein the uplink signal is a signal obtained by precoding a signal to be sent by the kth micro base station by using an uplink precoding matrix of the kth micro base station;
the macro base station generates an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink pre-coding matrix of the kth micro base station;
and the macro base station obtains the signal to be transmitted according to the uplink equivalent channel matrix of the kth micro base station and the uplink signal.
With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the obtaining, by the macro base station, a pre-cancellation weight of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station includes:
the macro base station calculates the pre-cancellation weight G of the downlink channel of the kth micro base station by using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station.
With reference to the first aspect and any one of the first to second possible implementation manners of the first aspect, in a third possible implementation manner of the first aspect, the determining, by the macro base station, a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station includes:
and the macro base station obtains the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the mutual difference between the uplink channel and the downlink channel of the kth micro base station.
With reference to any one of the first to third possible implementation manners of the first aspect, in a fourth possible implementation manner of the first aspect, the generating, by the macro base station, an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station includes:
the macro base station generates an uplink equivalent channel matrix of the kth micro base station according to the following formula:
Figure GDA0002236965200000031
wherein HkIs the uplink physical channel matrix, W, of the kth micro base stationkAnd the precoding matrix is an uplink precoding matrix of the kth micro base station.
With reference to the first aspect and any one of the first to fourth possible implementation manners of the first aspect, in a fifth possible implementation manner of the first aspect, the determining, by the macro base station, uplink precoding matrices of the N micro base stations according to uplink physical channel matrices of the N micro base stations includes:
in the ith iteration process, when the macro base station determines the uplink precoding matrix of the kth micro base station, the macro base station determines the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations except the kth micro base station and uplink precoding matrixes of the other micro base stations in the (i-1) th iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix;
the macro base station determines an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station;
the macro base station acts the interference weight of the interference suffered by the kth micro base station on the uplink channel of the kth micro base station to obtain an uplink equivalent channel matrix of the kth micro base station;
the macro base station determines an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station;
the macro base station determines an ith iteration result according to uplink precoding matrixes of the N micro base stations in an ith iteration process and uplink physical channel matrixes of the N micro base stations;
the macro base station determines whether to end the iteration process according to the ith iteration result;
if the iteration process is determined to be finished, respectively taking uplink precoding matrixes in the ith iteration process as uplink precoding matrixes of the N micro base stations;
and if the iteration process is determined not to be ended, adding one to the i, and performing the next iteration.
With reference to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner of the first aspect, the determining, by the macro base station, the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrices of other micro base stations except the kth micro base station and uplink precoding matrices of the other micro base stations in an i-1 th iteration process includes:
the macro base station determines an interference matrix generated by other micro base stations according to uplink physical channel matrixes of other micro base stations, uplink pre-coding matrixes of other micro base stations in the ith-1 th iteration process and a statistical covariance matrix of uplink interference;
and the macro base station decomposes the eigenvalue of the interference matrix to obtain the interference strength and the interference direction of the interference suffered by the kth micro base station.
The second aspect of the present invention provides a wireless communication method, including:
the micro base station sends an uplink pilot signal to the macro base station;
the micro base station receives a downlink pilot signal sent by the macro base station, wherein the downlink pilot signal is a signal obtained by precoding the downlink pilot signal by the macro base station according to a pre-cancellation weight of a downlink channel and an uplink precoding matrix of the micro base station, the downlink pilot signal is cancelled by precoding the pre-cancellation weight of the downlink channel of the micro base station and the downlink physical channel matrix of the micro base station, and the downlink pilot signal only comprises the uplink precoding matrix of the micro base station;
the micro base station performs channel estimation according to the received downlink pilot signal and the downlink pilot signal to obtain a downlink equivalent channel matrix, and determines that the downlink equivalent channel matrix is an uplink pre-coding matrix of the micro base station;
and the micro base station uses the uplink precoding matrix to precode a signal to be transmitted and then transmits the signal to the macro base station.
A third aspect of the present invention provides a macro base station, comprising:
the receiving module is used for receiving uplink pilot signals respectively sent by N micro base stations, wherein N is a positive integer greater than or equal to 2;
a first determining module, configured to determine, according to a received uplink pilot signal sent by a kth micro base station, an uplink physical channel matrix of the kth micro base station, where a value of k is 1, 2, … …, N;
a second determining module, configured to determine uplink precoding matrices of the N micro base stations according to the uplink physical channel matrices of the N micro base stations;
the first determining module is further configured to determine a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station;
a third determining module, configured to obtain a pre-cancellation weight of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station;
a sending module, configured to use the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and send the pre-coded downlink pilot signal to the kth micro base station, where the pre-cancellation weight of the downlink channel of the kth micro base station and the downlink physical channel matrix of the kth micro base station are cancelled out by pre-coding, and the downlink pilot signal received by the kth micro base station only includes the uplink pre-coding matrix of the kth micro base station.
With reference to the third aspect, in a first possible implementation manner of the third aspect, the macro base station further includes: the device comprises a generating module and an obtaining module;
the receiving module is further configured to receive an uplink signal sent by the kth micro base station, where the uplink signal is a signal precoded by the kth micro base station using an uplink precoding matrix of the kth micro base station;
the generating module is configured to generate an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station;
and the acquisition module is used for demodulating the uplink signal according to the uplink equivalent channel matrix of the kth micro base station.
With reference to the third aspect or the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, the third determining module is specifically configured to:
calculating a pre-cancellation weight G of a downlink channel of the kth micro base station by using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station.
With reference to the third aspect and any one of the first to second possible implementation manners of the third aspect, in a third possible implementation manner of the third aspect, the first determining module is specifically configured to:
and obtaining the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the mutual difference of the uplink channel and the downlink channel of the kth micro base station.
With reference to any one of the first to third possible implementation manners of the third aspect, in a fourth possible implementation manner of the third aspect, the generating module is specifically configured to:
generating an uplink equivalent channel matrix of the kth micro base station according to the following formula:
Figure GDA0002236965200000061
wherein HkIs the uplink physical channel matrix, W, of the kth micro base stationkAnd the precoding matrix is an uplink precoding matrix of the kth micro base station.
With reference to the third aspect and any one of the first to fourth possible implementation manners of the third aspect, in a fifth possible implementation manner of the third aspect, the second determining module is specifically configured to:
in the ith iteration process, when determining an uplink precoding matrix of the kth micro base station, determining the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations except the kth micro base station and uplink precoding matrixes of the other micro base stations in the ith-1 iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix;
determining an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station;
applying the interference weight of the interference suffered by the kth micro base station to an uplink channel of the kth micro base station to obtain an uplink equivalent channel matrix of the kth micro base station;
determining an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station;
determining an ith iteration result according to uplink precoding matrixes of the N micro base stations in the ith iteration process and uplink physical channel matrixes of the N micro base stations;
determining whether to end the iteration process according to the ith iteration result;
if the iteration process is determined to be finished, respectively taking uplink precoding matrixes in the ith iteration process as uplink precoding matrixes of the N micro base stations;
and if the iteration process is determined not to be ended, adding one to the i, and performing the next iteration.
With reference to the fifth possible implementation manner of the third aspect, in a sixth possible implementation manner of the third aspect, the second determining module is specifically configured to:
determining interference matrixes generated by other micro base stations according to uplink physical channel matrixes of other micro base stations, uplink precoding matrixes of other micro base stations in the ith-1 iteration process and statistical covariance matrixes of uplink interference;
and decomposing the eigenvalue of the interference matrix to obtain the interference intensity and the interference direction of the interference suffered by the kth micro base station.
A fourth aspect of the present invention provides a micro base station, including:
a sending module, configured to send an uplink pilot signal to a macro base station;
a receiving module, configured to receive a downlink pilot signal sent by the macro base station, where the downlink pilot signal is a signal obtained by precoding, by the macro base station, the downlink pilot signal according to a pre-cancellation weight of a downlink channel and an uplink precoding matrix of the micro base station, and is cancelled by precoding the pre-cancellation weight of the downlink channel of the micro base station and the downlink physical channel matrix of the micro base station, and the downlink pilot signal only includes the uplink precoding matrix of the micro base station;
a determining module, configured to perform channel estimation according to a received downlink pilot signal and the downlink pilot signal to obtain a downlink equivalent channel matrix, and determine that the downlink equivalent channel matrix is an uplink pre-coding matrix of the micro base station;
the sending module is further configured to send the signal to be sent to the macro base station after precoding the signal with the uplink precoding matrix.
In the wireless communication method, the macro base station and the micro base stations provided in the embodiments of the present invention, after obtaining a precoding matrix, the macro base station determines a downlink physical channel matrix of a kth micro base station, obtains a pre-cancellation weight of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station, and finally, uses the pre-cancellation weight and an uplink precoding matrix of the downlink channel to precode downlink pilot signals and then sends the downlink pilot signals to the kth micro base station, where the kth micro base station obtains a downlink equivalent channel matrix through channel estimation, determines the downlink equivalent channel matrix as an uplink precoding matrix of the kth micro base station, and performs uplink precoding according to the uplink precoding matrix. Because the uplink precoding matrix acquired by the micro base station is not quantized, the micro base station can acquire the high-precision uplink precoding matrix, so that the uplink precoding matrix can be optimally matched with an uplink channel, and the capacity of the uplink channel is improved.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are 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 diagram of a wireless backhaul system;
fig. 2 is a flowchart of a wireless communication method according to an embodiment of the present invention;
fig. 3 is a flowchart of a wireless communication method according to a second embodiment of the present invention;
fig. 4 is a flowchart of a method for calculating an uplink precoding matrix according to a third embodiment of the present invention;
fig. 5 is a flowchart of a wireless communication method according to a fourth embodiment of the present invention;
fig. 6 is a schematic structural diagram of a macro base station according to a fifth embodiment of the present invention;
fig. 7 is a schematic structural diagram of a macro base station according to a sixth embodiment of the present invention;
fig. 8 is a schematic structural diagram of a micro base station according to an eighth embodiment of the present invention;
fig. 9 is a schematic structural diagram of a macro base station according to a ninth embodiment of the present invention;
fig. 10 is a schematic structural diagram of a micro base station according to a tenth embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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.
The method of the embodiment of the present invention is applied to wireless backhaul communication, which is communication between a macro base station and a micro base station, fig. 1 is a schematic architecture diagram of a wireless backhaul system, and as shown in fig. 1, the wireless backhaul system includes: a plurality of macro base stations 11 and a plurality of micro base stations 12. The coverage range of the macro base station 11 is large, the coverage range of the micro base station 12 is small, the macro base station 11 performs main coverage, and the micro base station 12 is used for performing blind spot, hot spot capacity and coverage enhancement.
Fig. 2 is a flowchart of a wireless communication method according to an embodiment of the present invention, and as shown in fig. 2, the method according to this embodiment may include the following steps:
step 101, a macro base station receives uplink pilot signals respectively sent by N micro base stations, wherein N is a positive integer greater than or equal to 2.
The uplink pilot signal sent by the micro base station is a pilot signal which is not precoded, each micro base station can have a plurality of antenna ports (ports), each antenna Port sends an uplink pilot signal, the uplink pilot signals sent by the antenna ports can be distinguished in a code division mode, a frequency division mode, a time division mode and the like, and each base station distributes different pilot signals.
Step 102, the macro base station determines an uplink physical channel matrix of a kth micro base station according to the received uplink pilot signal sent by the kth micro base station, wherein the value of k is 1, 2, … …, N.
The macro base station obtains uplink physical channel matrixes of all micro base stations through a channel estimation method according to uplink pilot signals sent by the micro base stations, wherein the uplink physical channel matrixes of the micro base stations are physical channel matrixes which are not subjected to precoding weighting between the macro base stations and the micro base stations, and the uplink physical channel matrix of the kth micro base station is HkAnd (4) showing.
And step 103, the macro base station determines uplink precoding matrixes of the N micro base stations according to the uplink physical channel matrixes of the N micro base stations.
The uplink precoding matrix of the micro base station refers to a precoding matrix of an uplink channel of the micro base station, the macro base station can obtain the uplink precoding matrix of each micro base station by taking each layer and capacity maximization or approximation criteria as a conventional SU-MIMO precoding method according to the uplink physical channel matrix of each micro base station, or the macro base station obtains the uplink precoding matrix of each micro base station by taking each layer and capacity maximization or approximation criteria as an MU-MIMO precoding method according to the uplink physical channel matrix of each micro base station.
And step 104, the macro base station determines a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station.
The macro base station may obtain the downlink physical channel matrix of the kth micro base station by using the uplink physical channel matrix of the kth micro base station and the reciprocity of the uplink channel and the downlink channel. For Time Division Duplex (TDD) system, macro baseAnd the station calculates the transpose matrix of the uplink physical channel matrix of the kth micro base station and determines that the transpose matrix of the uplink physical channel matrix of the kth micro base station is the downlink physical channel matrix of the kth micro base station. H 'for downlink physical channel matrix of kth micro base station'kIs shown to be
Figure GDA0002236965200000094
H‘kHas the dimension of
Figure GDA0002236965200000092
Wherein,denotes the number of antennas of the kth micro base station, NBSIndicating the number of antennas of the macro base station.
And 105, the macro base station obtains the pre-cancellation weight of the downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station.
The pre-cancellation weight value is used for counteracting a downlink physical channel matrix of the kth micro base station, a downlink pilot signal received by the kth micro base station after the counteraction only comprises an uplink precoding matrix of the kth micro base station, and the kth micro base station can obtain the uplink precoding matrix through channel estimation. If cancellation is not performed, the macro base station directly uses the uplink precoding matrix to perform downlink precoding, then the downlink pilot signal received by the kth micro base station is the superposition of the uplink precoding matrix, the downlink physical channel matrix and the downlink pilot signal, and the micro base station cannot distinguish the uplink precoding matrix from the downlink physical channel matrix through channel estimation, so that the uplink precoding matrix cannot be obtained. In this embodiment, the macro base station obtains the pre-cancellation weight of the downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station, and then performs precoding using the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink precoding matrix.
In one implementation, the macro base station may calculate the pre-cancellation weight G of the downlink channel of the kth micro base station using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station, GkThe following conditions need to be satisfied: the number of antennas of the macro base station is not less than the number of antennas of the kth micro base station. However, it can be understood that the pre-cancellation weight G of the downlink channel of the kth micro base stationkThe specific form of (c) is not limited to the above formula, but may be calculated in other ways.
And step 106, the macro base station uses the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and then sends the pre-coded downlink pilot signal to the kth micro base station.
Pre-cancellation weight values of a downlink channel of a kth micro base station and a downlink physical channel matrix of the kth micro base station are cancelled by pre-coding, and downlink pilot signals received by the kth micro base station only comprise an uplink pre-coding matrix of the kth micro base station.
The uplink precoding matrix W of the kth micro base station can be obtainedkAs the 1 st weighting, the pre-cancellation weight G of the downlink channel of the kth micro base station is usedkPrecoding with hierarchical weighting as a level 2 weighting, the signal precoded by the macro base station being denoted GkWks, s denote downlink pilot signals. The precoded signal is transmitted through the downlink channel of the kth micro base station, and the downlink pilot signal received by the kth micro base station is represented as yk＝H‘kGkWks + u, u represents the interference of the downlink channel. G is to bek＝(H'k)H[H'k(H'k)H]-1Carry in ykObtaining:
Figure GDA0002236965200000101
can be obtained by the formulaWherein,
Figure GDA0002236965200000103
and indicating a downlink equivalent channel matrix of the kth micro base station. After receiving the downlink pilot signal, the micro base station performs channel estimation according to the downlink pilot signal and the downlink pilot signal s to obtain
Figure GDA0002236965200000104
And u, due toTherefore, the k-th micro base station is directly estimated
Figure GDA0002236965200000106
As an uplink precoding matrix WkThen, according to the uplink precoding matrix WkAnd performing uplink precoding.
In the prior art, after a macro base station acquires an uplink precoding matrix, a precoding matrix is quantized to obtain a codebook corresponding to the uplink precoding matrix, and then the codebook is sent to a micro base station through signaling, so that errors are introduced into the quantization of the precoding matrix, and the precision of the precoding matrix is low. In this embodiment, after acquiring the precoding matrix, the macro base station does not perform quantization of the precoding matrix, but determines the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station, according to the downlink physical channel matrix of the kth micro base station, obtaining the pre-offset weight of the downlink channel of the kth micro base station, and finally, using the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station, the downlink pilot signal is pre-coded and then sent to the kth micro base station, because the pre-offset weight of the downlink channel of the k micro base station and the downlink physical channel matrix of the kth micro base station are offset by pre-coding, and the downlink pilot signal received by the kth micro base station only comprises the uplink precoding matrix of the kth micro base station, so that the uplink precoding matrix can be sent to the micro base station. Because the uplink precoding matrix sent by the macro base station is not quantized, the micro base station can acquire the high-precision uplink precoding matrix, so that the uplink precoding matrix can be optimally matched with an uplink channel, and the capacity of the uplink channel is improved.
Fig. 3 is a flowchart of a wireless communication method according to a second embodiment of the present invention, and as shown in fig. 3, the method according to the second embodiment includes the following steps:
step 201, a macro base station receives uplink pilot signals respectively sent by N micro base stations, where N is a positive integer greater than or equal to 2.
Step 202, the macro base station determines an uplink physical channel matrix of the kth micro base station according to the received uplink pilot signal sent by the kth micro base station, wherein the value of k is 1, 2, … …, N.
And 203, the macro base station determines uplink precoding matrixes of the N micro base stations according to the uplink physical channel matrixes of the N micro base stations.
And step 204, the macro base station determines a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station.
Step 205, the macro base station obtains the pre-cancellation weight of the downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station.
Step 206, the macro base station uses the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and then sends the pre-coded downlink pilot signal to the kth micro base station.
Pre-cancellation weight values of a downlink channel of a kth micro base station and a downlink physical channel matrix of the kth micro base station are cancelled by pre-coding, and downlink pilot signals received by the kth micro base station only comprise an uplink pre-coding matrix of the kth micro base station.
The specific implementation manner of steps 201-206 may refer to the implementation manner of steps 101-106 in the embodiment, and will not be described herein again.
Step 207, the macro base station receives the uplink signal sent by the kth micro base station, where the uplink signal is a signal obtained by precoding, by the kth micro base station, a signal to be sent by using the uplink precoding matrix of the kth micro base station.
After receiving a downlink pilot signal sent by the macro base station, the kth micro base station performs channel estimation to obtain a downlink equivalent channel matrix, the downlink equivalent channel matrix is used as an uplink precoding matrix, then the kth micro base station performs precoding on a signal to be sent by using the uplink precoding matrix and sends the signal to the macro base station through an uplink channel of the kth micro base station, and the macro base station receives an uplink signal sent by the kth micro base station. The uplink signal received by the macro base station and sent by the kth micro base station may be represented as:
y′k＝HkWks' + u, wherein HkRepresents the uplink physical channel matrix, W, of the kth micro base stationkAnd the uplink precoding matrix of the kth micro base station is represented, s' represents a signal to be transmitted, and u represents the interference of an uplink channel of the kth micro base station.
And step 208, the macro base station generates an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink pre-coding matrix of the kth micro base station.
The uplink equivalent channel matrix of the kth micro base station is represented as:
Figure GDA0002236965200000121
and step 209, the macro base station obtains a signal to be transmitted according to the uplink equivalent channel matrix and the uplink signal of the kth micro base station.
Macro base station according to y'k＝HkWks' + u and
Figure GDA0002236965200000122
and carrying out data demodulation to obtain a signal s' to be transmitted.
In this embodiment, the macro base station receives an uplink signal sent by a kth micro base station, where the uplink signal is a signal precoded by the kth micro base station using an uplink precoding matrix of the kth micro base station, generates an uplink equivalent channel matrix of the kth micro base station according to an uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station, and demodulates the uplink signal according to the uplink equivalent channel matrix of the kth micro base station, so that the uplink signal sent by the micro base station can be successfully demodulated. Because the uplink signal is a signal which is precoded by the micro base station by using the uplink precoding matrix sent by the macro base station, the uplink precoding matrix can be optimally matched with the uplink channel, and the capacity of the uplink channel is improved.
The codebook-based precoding mechanism has a disadvantage, in addition to the above-mentioned problem that the precision of the precoding matrix is low due to the error introduced by the quantization of the precoding matrix: the number of available precoding codebooks is generally limited, so that multi-user MIMO cannot cooperate effectively, and the problem of multi-user interference exists. Especially in multi-user high-order MIMO, inter-user interference is more severe. In order to solve the problem of interference among multiple users, on the basis of the first embodiment and the second embodiment, a third embodiment of the present invention provides a method for calculating an uplink precoding matrix, which can effectively perform preprocessing and cooperation on interference among multiple uplink users, and improve spatial multiplexing rate and spectral efficiency of multiple uplink users. Fig. 4 is a flowchart of a method for calculating an uplink precoding matrix according to a third embodiment of the present invention, and as shown in fig. 4, the method according to the third embodiment includes the following steps:
step 301, in the ith iteration process, when the macro base station determines the uplink precoding matrix of the kth micro base station, the macro base station determines the interference strength and the interference direction of the interference suffered by the kth micro base station according to the uplink physical channel matrices of other micro base stations except the kth micro base station and the uplink precoding matrices of the other micro base stations in the ith-1 iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix.
In one implementation mode, a macro base station determines an interference matrix of interference suffered by a kth micro base station according to uplink physical channel matrixes of other micro base stations, uplink precoding matrixes of other micro base stations in an i-1 iteration process and a statistical covariance matrix of uplink interference; then, the eigenvalue decomposition is performed on the interference matrix to obtain the interference strength and the interference direction of the interference received by the kth micro base station.
Wherein the interference moment of the interference suffered by the k-th micro base stationThe array can be calculated by the following formula:
Figure GDA0002236965200000131
and j ≠ k, HjRepresents the uplink physical channel matrix of the j-th micro base station,and (3) representing an uplink precoding matrix of the jth micro base station in the ith-1 iteration process, and I representing a statistical covariance matrix of uplink interference.
The eigenvalue decomposition of the interference matrix can be expressed asWherein, UkFor the interference direction of the interference experienced by the kth micro base station, DkThe interference strength of the interference suffered by the kth micro base station.
Taking N equal to 2 as an example, that is, there are two micro base stations in total, in the first iteration process, the signal received by the macro base station is
Figure GDA0002236965200000134
Represents the uplink physical channel matrix of the 1 st micro base station in the first iteration process,
Figure GDA0002236965200000136
and the uplink physical channel matrix of the 1 st micro base station in the first iteration process is shown, and u represents the uplink interference of the 1 st micro base station. The macro base station obtains the normal SU-MIMO precoding method through each layer and capacity maximization or approximation criterion
Figure GDA0002236965200000137
The specific method includes but is not limited to channel characteristic decomposition, power water injection and the like, and the number of reusable space division layers N is assumed after precodingLThen, thenHas the dimension of
Figure GDA0002236965200000141
Figure GDA0002236965200000142
Indicating the number of antennas of the 1 st micro base station.
Is obtained by
Figure GDA0002236965200000143
Then, the macro base station obtains the result according to the formula
Figure GDA0002236965200000144
Then to R1And (3) carrying out characteristic value decomposition: EVD (R)1)＝U1D1U1 HWherein, U1Indicates the interference direction received by the 1 st micro base station, D1Indicating the strength of the interference experienced by the 1 st micro base station.
Step 302, the macro base station determines an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station.
The interference weight may specifically be calculated in the following manner:
Figure GDA0002236965200000145
Ukfor the interference direction of the interference experienced by the kth micro base station, DkThe interference strength of the interference suffered by the kth micro base station.
Step 303, the macro base station applies the interference weight of the interference suffered by the kth micro base station to the uplink channel of the kth micro base station to obtain the uplink equivalent channel matrix of the kth micro base station.
The uplink equivalent channel matrix of the kth micro base station can be calculated by the following formula:
Figure GDA0002236965200000146
Hkchannel matrix, G, of the uplink channel of the kth micro base stationkAnd representing the interference weight of the interference suffered by the kth micro base station.
And step 304, the macro base station determines an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station.
The uplink precoding matrix of the kth micro base station in the ith iteration process can be represented as:
Figure GDA0002236965200000147
Figure GDA0002236965200000148
is shown in
Figure GDA0002236965200000149
The method is used for calculating the single-user precoding matrix under the condition of taking the additive noise covariance as a unit matrix as a channel matrix.
And 305, the macro base station determines the ith iteration result according to the uplink precoding matrixes of the N micro base stations in the ith iteration process and the uplink physical channel matrixes of the N micro base stations.
The result of the ith iteration can be represented by a capacity sum, wherein the capacity sum can be calculated by the following formula:
Figure GDA00022369652000001410
the operator | · | represents a determinant of the computation matrix.
And step 306, the macro base station determines whether to end the iteration process according to the ith iteration result.
Specifically, the sum of capacities in the ith iteration process may be compared with a set expected value, if the sum of capacities in the ith iteration process is greater than or equal to the expected value, the iteration process is determined to be ended, step 307 is executed, and if the sum of capacities in the ith iteration process is less than the expected value, the iteration process is determined not to be ended, and step 308 is executed. Or comparing the capacity sum in the ith iteration process with the capacity sum in the (i-1) th iteration process, determining to finish the iteration process if the difference of the capacity sums in the two iteration processes is smaller than a preset value, and determining not to finish the iteration process if the difference of the capacity sums in the two iteration processes is larger than or equal to the preset value.
And 307, taking the uplink precoding matrix in the ith iteration process as uplink precoding matrices of the N micro base stations respectively.
And step 308, adding one to the i, and performing the next iteration.
In this embodiment, the macro base station alternately uses a signal sent by a certain micro base station as a target signal and uses signals sent by other micro base stations as interference, and determines an uplink precoding matrix of each micro base station under the condition of multi-user interference, so that the uplink multi-user interference can be effectively preprocessed and coordinated, the uplink multi-user space division multiplexing rate and the spectrum efficiency are improved, and the capacity of an uplink channel is further prompted.
Fig. 5 is a flowchart of a wireless communication method according to a fourth embodiment of the present invention, and as shown in fig. 5, the method according to the present embodiment includes the following steps:
step 401, the micro base station sends an uplink pilot signal to the macro base station.
The uplink pilot signal sent by the micro base station is not pre-coded.
Step 402, the micro base station receives a downlink pilot signal sent by the macro base station, the downlink pilot signal is a signal obtained by precoding the downlink pilot signal by the macro base station according to the pre-cancellation weight of the downlink channel and the uplink precoding matrix of the micro base station, the downlink pilot signal is cancelled by the pre-cancellation weight of the downlink channel of the pre-coding micro base station and the downlink physical channel matrix of the micro base station, and the downlink pilot signal only comprises the uplink precoding matrix of the micro base station.
Step 403, the micro base station performs channel estimation according to the received downlink pilot signal and the downlink pilot signal to obtain a downlink equivalent channel matrix, and determines that the downlink equivalent channel matrix is an uplink pre-coding matrix of the micro base station.
And step 404, the micro base station uses the uplink precoding matrix to precode the signal to be transmitted and then transmits the signal to the macro base station.
The specific implementation manner of this embodiment may refer to the description related to the second embodiment, and is not described herein again.
In this embodiment, the micro base station receives a downlink pilot signal sent by the macro base station, performs channel estimation according to the received downlink pilot signal and the downlink pilot signal to obtain a downlink equivalent channel matrix, determines that the downlink equivalent channel matrix is an uplink precoding matrix of the micro base station, and sends a signal to be sent to the macro base station after precoding the signal by using the uplink precoding matrix. Because the uplink signal is a signal which is precoded by the micro base station by using the uplink precoding matrix sent by the macro base station, the uplink precoding matrix can be optimally matched with the uplink channel, and the capacity of the uplink channel is improved.
Fig. 6 is a schematic structural diagram of a macro base station according to a fifth embodiment of the present invention, and as shown in fig. 6, the macro base station according to the present embodiment includes: a receiving module 21, a first determining module 22, a second determining module 23, a third determining module 24 and a sending module 25.
The receiving module 21 is configured to receive uplink pilot signals sent by N micro base stations, where N is a positive integer greater than or equal to 2;
a first determining module 22, configured to determine, according to a received uplink pilot signal sent by a kth micro base station, an uplink physical channel matrix of the kth micro base station, where a value of k is 1, 2, … …, N;
a second determining module 23, configured to determine uplink precoding matrices of the N micro base stations according to the uplink physical channel matrices of the N micro base stations;
the first determining module 22 is further configured to determine a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station;
a third determining module 24, configured to obtain a pre-cancellation weight of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station;
a sending module 25, configured to use the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and send the pre-coded downlink pilot signal to the kth micro base station, where the pre-cancellation weight of the downlink channel of the kth micro base station and the downlink physical channel matrix of the kth micro base station are cancelled out by pre-coding, and the downlink pilot signal received by the kth micro base station only includes the uplink pre-coding matrix of the kth micro base station.
Optionally, the third determining module 24 is specifically configured to:
calculating a pre-cancellation weight G of a downlink channel of the kth micro base station by using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station.
Optionally, the first determining module is specifically configured to: and obtaining the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the mutual difference of the uplink channel and the downlink channel of the kth micro base station.
The macro base station provided in this embodiment may be configured to execute the method of the first embodiment, and the specific implementation manner and the technical effect are similar, which are not described herein again.
Fig. 7 is a schematic structural diagram of a macro base station according to a sixth embodiment of the present invention, and as shown in fig. 7, the macro base station according to the present embodiment further includes, on the basis of fig. 6: a generation module 26 and an acquisition module 27.
The receiving module 21 is further configured to receive an uplink signal sent by the kth micro base station, where the uplink signal is a signal precoded by the kth micro base station using an uplink precoding matrix of the kth micro base station;
the generating module 26 is configured to generate an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station;
the obtaining module 27 is configured to demodulate the uplink signal according to the uplink equivalent channel matrix of the kth micro base station.
Optionally, the generating module 26 is specifically configured to:
generating an uplink equivalent channel matrix of the kth micro base station according to the following formula:
Figure GDA0002236965200000171
wherein HkIs the uplink physical channel matrix, W, of the kth micro base stationkAnd the precoding matrix is an uplink precoding matrix of the kth micro base station.
The macro base station provided in this embodiment may be used to execute the method of the second embodiment, and the specific implementation manner and the technical effect are similar, which are not described herein again.
A seventh embodiment of the present invention provides a macro base station, where in the structure of the macro base station in this embodiment, referring to the macro base station shown in fig. 7, on the basis of the sixth embodiment, in this embodiment, the second determining module 23 is specifically configured to:
in the ith iteration process, when determining an uplink precoding matrix of the kth micro base station, determining the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations except the kth micro base station and uplink precoding matrixes of the other micro base stations in the ith-1 iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix;
determining an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station;
applying the interference weight of the interference suffered by the kth micro base station to an uplink channel of the kth micro base station to obtain an uplink equivalent channel matrix of the kth micro base station;
determining an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station;
determining an ith iteration result according to uplink precoding matrixes of the N micro base stations in the ith iteration process and uplink physical channel matrixes of the N micro base stations;
determining whether to end the iteration process according to the ith iteration result;
if the iteration process is determined to be finished, respectively taking uplink precoding matrixes in the ith iteration process as uplink precoding matrixes of the N micro base stations;
and if the iteration process is determined not to be ended, adding one to the i, and performing the next iteration.
Optionally, when determining the interference strength and the interference direction of the interference received by the kth micro base station, the second determining module is specifically configured to: determining interference matrixes generated by other micro base stations according to uplink physical channel matrixes of other micro base stations, uplink precoding matrixes of other micro base stations in the ith-1 iteration process and statistical covariance matrixes of uplink interference; and decomposing the eigenvalue of the interference matrix to obtain the interference intensity and the interference direction of the interference suffered by the kth micro base station.
The macro base station provided in this embodiment may be used to execute the method of the third embodiment, and the specific implementation manner and the technical effect are similar, and are not described here again.
Fig. 8 is a schematic structural diagram of a micro base station according to an eighth embodiment of the present invention, and as shown in fig. 8, the micro base station according to the present embodiment includes: a sending module 31, a receiving module 32 and a determining module 33.
The sending module 31 is configured to send an uplink pilot signal to the macro base station;
a receiving module 32, configured to receive a downlink pilot signal sent by the macro base station, where the downlink pilot signal is a signal obtained by precoding, by the macro base station, the downlink pilot signal according to a pre-cancellation weight of a downlink channel and an uplink precoding matrix of the micro base station, and is cancelled by precoding the pre-cancellation weight of the downlink channel of the micro base station and a downlink physical channel matrix of the micro base station, and the downlink pilot signal only includes the uplink precoding matrix of the micro base station;
a determining module 33, configured to perform channel estimation according to the received downlink pilot signal and the downlink pilot signal to obtain the downlink equivalent channel matrix, and determine that the downlink equivalent channel matrix is an uplink pre-coding matrix of the micro base station;
the sending module 31 is further configured to send the signal to be sent to the macro base station after precoding the signal with the uplink precoding matrix.
The micro base station provided in this embodiment may be used to execute the method of the fourth embodiment, and the specific implementation manner and the technical effect are similar, which are not described herein again.
Fig. 9 is a schematic structural diagram of a macro base station according to a ninth embodiment of the present invention, and as shown in fig. 9, the macro base station 400 according to the present embodiment includes: a transmitter 41, a receiver 42, a processor 43 and a memory 44, wherein the transmitter 41, the receiver 42 and the memory 44 are connected with the processor 43 through a system bus and communicate; the memory 44 for storing computer-executable instructions; the processor 43 is configured to execute the computer execution instruction.
The receiver 42 is configured to receive uplink pilot signals respectively sent by N micro base stations, where N is a positive integer greater than or equal to 2.
The processor 43 is configured to: determining an uplink physical channel matrix of a kth micro base station according to a received uplink pilot signal sent by the kth micro base station, wherein the value of k is 1, 2, … …, N;
determining uplink precoding matrixes of the N micro base stations according to the uplink physical channel matrixes of the N micro base stations;
determining a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station;
and obtaining a pre-cancellation weight value of the downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station.
The transmitter 41 is configured to use the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and then send the pre-coded downlink pilot signal to the kth micro base station, so that the pre-cancellation weight of the downlink channel of the kth micro base station and the downlink physical channel matrix of the kth micro base station are cancelled out by pre-coding, and the downlink pilot signal received by the kth micro base station only includes the uplink pre-coding matrix of the kth micro base station.
The receiver 42 is further configured to receive an uplink signal sent by the kth micro base station, where the uplink signal is a signal obtained by precoding, by the kth micro base station, a signal to be sent by using an uplink precoding matrix of the kth micro base station;
the processor 43 is further configured to: generating an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink pre-coding matrix of the kth micro base station; and obtaining the signal to be transmitted according to the uplink equivalent channel matrix of the kth micro base station and the uplink signal.
Optionally, the processor 43 obtains the pre-cancellation weight of the downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station, specifically:
calculating a pre-cancellation weight G of a downlink channel of the kth micro base station by using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station.
Optionally, the processor 43 determines the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station, specifically:
and obtaining the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the mutual difference of the uplink channel and the downlink channel of the kth micro base station.
Optionally, the processor 43 generates an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station, specifically:
generating an uplink equivalent channel matrix of the kth micro base station according to the following formula:
Figure GDA0002236965200000201
wherein HkIs the uplink physical channel matrix, W, of the kth micro base stationkAnd the precoding matrix is an uplink precoding matrix of the kth micro base station.
Optionally, the processor 43 determines the uplink precoding matrices of the N micro base stations according to the uplink physical channel matrices of the N micro base stations, specifically:
in the ith iteration process, when determining an uplink precoding matrix of the kth micro base station, the macro base station determines the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations except the kth micro base station and uplink precoding matrixes of the other micro base stations in the ith-1 iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix;
determining an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station;
applying the interference weight of the interference suffered by the kth micro base station to an uplink channel of the kth micro base station to obtain an uplink equivalent channel matrix of the kth micro base station;
determining an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station;
determining an ith iteration result according to uplink precoding matrixes of the N micro base stations in the ith iteration process and uplink physical channel matrixes of the N micro base stations;
determining whether to end the iteration process according to the ith iteration result;
if the iteration process is determined to be finished, respectively taking uplink precoding matrixes in the ith iteration process as uplink precoding matrixes of the N micro base stations;
and if the iteration process is determined not to be ended, adding one to the i, and performing the next iteration.
Optionally, the processor 43 determines, according to uplink physical channel matrices of other micro base stations except for the kth micro base station and uplink precoding matrices of the other micro base stations in the i-1 th iteration process, an interference strength and an interference direction of interference suffered by the kth micro base station, specifically:
determining an interference matrix of interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations, uplink precoding matrixes of other micro base stations in the ith-1 th iteration process and a statistical covariance matrix of uplink interference; and decomposing the eigenvalue of the interference matrix to obtain the interference intensity and the interference direction of the interference suffered by the kth micro base station.
The macro base station of this embodiment may be configured to execute the solutions of the first to third embodiments, and the specific implementation manner and the technical effect are similar, which are not described herein again.
Fig. 10 is a schematic structural diagram of a micro base station according to a tenth embodiment of the present invention, and as shown in fig. 10, a micro base station 500 according to the present embodiment includes: a transmitter 51, a receiver 52, a processor 53 and a memory 54, wherein the transmitter 51, the receiver 52 and the memory 54 are connected with the processor 53 through a system bus and communicate; the memory 54 for storing computer-executable instructions; the processor 53 is configured to execute the computer execution instruction.
The transmitter 51 is configured to send an uplink pilot signal to a macro base station;
the receiver 52 is configured to receive a downlink pilot signal sent by the macro base station, where the downlink pilot signal is a signal obtained by precoding, by the macro base station, the downlink pilot signal according to a pre-cancellation weight of a downlink channel and the uplink precoding matrix of the micro base station, and is cancelled by precoding the pre-cancellation weight of the downlink channel of the micro base station and the downlink physical channel matrix of the micro base station, and the downlink pilot signal only includes the uplink precoding matrix of the micro base station;
the processor 53 is configured to perform channel estimation according to the received downlink pilot signal and the downlink pilot signal to obtain the downlink equivalent channel matrix, and determine that the downlink equivalent channel matrix is the uplink precoding matrix of the micro base station;
the transmitter 51 is further configured to precode a signal to be transmitted by using the uplink precoding matrix and transmit the precoded signal to the macro base station.
The micro base station of this embodiment may be configured to execute the scheme of the fourth embodiment, and the specific implementation manner and the technical effect are similar, which are not described herein again.
Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (16)

1. A method of wireless communication, comprising:
a macro base station receives uplink pilot signals respectively sent by N micro base stations, wherein N is a positive integer greater than or equal to 2;
the macro base station determines an uplink physical channel matrix of a kth micro base station according to a received uplink pilot signal sent by the kth micro base station, wherein the value of k is 1, 2, … …, N;
the macro base station determines uplink precoding matrixes of the N micro base stations according to the uplink physical channel matrixes of the N micro base stations;
the macro base station determines a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station;
the macro base station obtains a pre-cancellation weight value of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station;
the macro base station uses the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and then sends the pre-coded downlink pilot signal to the kth micro base station, the pre-cancellation weight of the downlink channel of the kth micro base station and the downlink physical channel matrix of the kth micro base station are cancelled out through pre-coding, and the downlink pilot signal received by the kth micro base station only comprises the uplink pre-coding matrix of the kth micro base station.
2. The method of claim 1, further comprising:
the macro base station receives an uplink signal sent by the kth micro base station, wherein the uplink signal is a signal obtained by precoding a signal to be sent by the kth micro base station by using an uplink precoding matrix of the kth micro base station;
the macro base station generates an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink pre-coding matrix of the kth micro base station;
and the macro base station obtains the signal to be transmitted according to the uplink equivalent channel matrix of the kth micro base station and the uplink signal.
3. The method according to claim 1 or 2, wherein the macro base station obtaining, according to the downlink physical channel matrix of the kth micro base station, the pre-cancellation weight of the downlink channel of the kth micro base station includes:
the macro base station calculates the pre-cancellation weight G of the downlink channel of the kth micro base station by using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station.
4. The method according to claim 1 or 2, wherein the macro base station determines the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station, and the determining comprises:
and the macro base station obtains the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the mutual difference between the uplink channel and the downlink channel of the kth micro base station.
5. The method according to claim 2, wherein the macro base station generates the uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station, and includes:
the macro base station generates an uplink equivalent channel matrix of the kth micro base station according to the following formula:
Figure FDA0002236965190000021
wherein HkIs the uplink physical channel matrix, W, of the kth micro base stationkAnd the precoding matrix is an uplink precoding matrix of the kth micro base station.
6. The method according to claim 1 or 2, wherein the macro base station determines the uplink precoding matrices of the N micro base stations according to the uplink physical channel matrices of the N micro base stations, and the method comprises:
in the ith iteration process, when the macro base station determines the uplink precoding matrix of the kth micro base station, the macro base station determines the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations except the kth micro base station and uplink precoding matrixes of the other micro base stations in the (i-1) th iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix;
the macro base station determines an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station;
the macro base station acts the interference weight of the interference suffered by the kth micro base station on the uplink channel of the kth micro base station to obtain an uplink equivalent channel matrix of the kth micro base station;
the macro base station determines an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station;
the macro base station determines an ith iteration result according to uplink precoding matrixes of the N micro base stations in an ith iteration process and uplink physical channel matrixes of the N micro base stations;
the macro base station determines whether to end the iteration process according to the ith iteration result;
if the iteration process is determined to be finished, respectively taking uplink precoding matrixes in the ith iteration process as uplink precoding matrixes of the N micro base stations;
and if the iteration process is determined not to be ended, adding one to the i, and performing the next iteration.
7. The method according to claim 6, wherein the macro base station determines the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrices of other micro base stations except the kth micro base station and uplink precoding matrices of the other micro base stations in the i-1 th iteration process, including:
the macro base station determines an interference matrix of interference suffered by the kth micro base station according to uplink physical channel matrixes of the other micro base stations, uplink pre-coding matrixes of the other micro base stations in the ith-1 th iteration process and a statistical covariance matrix of uplink interference;
and the macro base station decomposes the eigenvalue of the interference matrix to obtain the interference strength and the interference direction of the interference suffered by the kth micro base station.
8. A method of wireless communication, comprising:
the micro base station sends an uplink pilot signal to the macro base station;
the micro base station receives a downlink pilot signal sent by the macro base station, wherein the downlink pilot signal is a signal obtained by precoding the downlink pilot signal by the macro base station according to a pre-cancellation weight of a downlink channel and an uplink precoding matrix of the micro base station, the downlink pilot signal is cancelled by precoding the pre-cancellation weight of the downlink channel of the micro base station and the downlink physical channel matrix of the micro base station, and the downlink pilot signal only comprises the uplink precoding matrix of the micro base station;
the micro base station performs channel estimation according to the received downlink pilot signal and the downlink pilot signal to obtain a downlink equivalent channel matrix, and determines that the downlink equivalent channel matrix is an uplink pre-coding matrix of the micro base station;
and the micro base station uses the uplink precoding matrix to precode a signal to be transmitted and then transmits the signal to the macro base station.
9. A macro base station, comprising:
the receiving module is used for receiving uplink pilot signals respectively sent by N micro base stations, wherein N is a positive integer greater than or equal to 2;
a first determining module, configured to determine, according to a received uplink pilot signal sent by a kth micro base station, an uplink physical channel matrix of the kth micro base station, where a value of k is 1, 2, … …, N;
a second determining module, configured to determine uplink precoding matrices of the N micro base stations according to the uplink physical channel matrices of the N micro base stations;
the first determining module is further configured to determine a downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station;
a third determining module, configured to obtain a pre-cancellation weight of a downlink channel of the kth micro base station according to the downlink physical channel matrix of the kth micro base station;
a sending module, configured to use the pre-cancellation weight of the downlink channel of the kth micro base station and the uplink pre-coding matrix of the kth micro base station to pre-code the downlink pilot signal and send the pre-coded downlink pilot signal to the kth micro base station, where the pre-cancellation weight of the downlink channel of the kth micro base station and the downlink physical channel matrix of the kth micro base station are cancelled out by pre-coding, and the downlink pilot signal received by the kth micro base station only includes the uplink pre-coding matrix of the kth micro base station.
10. A macro base station according to claim 9, further comprising: the device comprises a generating module and an obtaining module;
the receiving module is further configured to receive an uplink signal sent by the kth micro base station, where the uplink signal is a signal precoded by the kth micro base station using an uplink precoding matrix of the kth micro base station;
the generating module is configured to generate an uplink equivalent channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the uplink precoding matrix of the kth micro base station;
and the acquisition module is used for demodulating the uplink signal according to the uplink equivalent channel matrix of the kth micro base station.
11. A macro base station according to claim 9 or 10, wherein the third determining module is specifically configured to:
calculating a pre-cancellation weight G of a downlink channel of the kth micro base station by using the following formulak：
Gk＝(H'k)H[H'k(H'k)H]-1Wherein, H'kIs the downlink physical channel matrix of the kth micro base station.
12. A macro base station according to claim 9 or 10, wherein the first determining module is specifically configured to:
and obtaining the downlink physical channel matrix of the kth micro base station according to the uplink physical channel matrix of the kth micro base station and the mutual difference of the uplink channel and the downlink channel of the kth micro base station.
13. A macro base station according to claim 10, wherein the generating module is specifically configured to:
generating an uplink equivalent channel matrix of the kth micro base station according to the following formula:
Figure FDA0002236965190000051
wherein HkIs the uplink physical channel matrix, W, of the kth micro base stationkAnd the precoding matrix is an uplink precoding matrix of the kth micro base station.
14. A macro base station according to claim 9 or 10, wherein the second determining module is specifically configured to:
in the ith iteration process, when determining an uplink precoding matrix of the kth micro base station, determining the interference strength and the interference direction of the interference suffered by the kth micro base station according to uplink physical channel matrixes of other micro base stations except the kth micro base station and uplink precoding matrixes of the other micro base stations in the ith-1 iteration process, wherein the initial value of k is 1, the initial value of i is also 1, and the initial value of the uplink precoding matrix of each micro base station is a unit matrix;
determining an interference weight of the interference suffered by the kth micro base station according to the interference strength and the interference direction of the interference suffered by the kth micro base station;
applying the interference weight of the interference suffered by the kth micro base station to an uplink channel of the kth micro base station to obtain an uplink equivalent channel matrix of the kth micro base station;
determining an uplink precoding matrix of the kth micro base station in the ith iteration process according to the uplink equivalent channel matrix of the kth micro base station;
determining an ith iteration result according to uplink precoding matrixes of the N micro base stations in the ith iteration process and uplink physical channel matrixes of the N micro base stations;
determining whether to end the iteration process according to the ith iteration result;
if the iteration process is determined to be finished, respectively taking uplink precoding matrixes in the ith iteration process as uplink precoding matrixes of the N micro base stations;
and if the iteration process is determined not to be ended, adding one to the i, and performing the next iteration.
15. A macro base station according to claim 14, wherein the second determining module is specifically configured to:
determining interference matrixes generated by other micro base stations according to uplink physical channel matrixes of other micro base stations, uplink precoding matrixes of other micro base stations in the ith-1 iteration process and statistical covariance matrixes of uplink interference;
and decomposing the eigenvalue of the interference matrix to obtain the interference intensity and the interference direction of the interference suffered by the kth micro base station.
16. A micro base station, comprising:
a sending module, configured to send an uplink pilot signal to a macro base station;
a receiving module, configured to receive a downlink pilot signal sent by the macro base station, where the downlink pilot signal is a signal obtained by precoding, by the macro base station, the downlink pilot signal according to a pre-cancellation weight of a downlink channel and an uplink precoding matrix of the micro base station, and is cancelled by precoding the pre-cancellation weight of the downlink channel of the micro base station and the downlink physical channel matrix of the micro base station, and the downlink pilot signal only includes the uplink precoding matrix of the micro base station;
a determining module, configured to perform channel estimation according to a received downlink pilot signal and the downlink pilot signal to obtain a downlink equivalent channel matrix, and determine that the downlink equivalent channel matrix is an uplink pre-coding matrix of the micro base station;
the sending module is further configured to send the signal to be sent to the macro base station after precoding the signal with the uplink precoding matrix.
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