WO2021047311A1 - 上行多站点信道估计的方法、站点和接入点 - Google Patents

上行多站点信道估计的方法、站点和接入点 Download PDF

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Publication number
WO2021047311A1
WO2021047311A1 PCT/CN2020/104898 CN2020104898W WO2021047311A1 WO 2021047311 A1 WO2021047311 A1 WO 2021047311A1 CN 2020104898 W CN2020104898 W CN 2020104898W WO 2021047311 A1 WO2021047311 A1 WO 2021047311A1
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training sequences
matrix
sta
frame
information
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PCT/CN2020/104898
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English (en)
French (fr)
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袁方超
陈鹏
杨博
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华为技术有限公司
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Priority to EP20863327.1A priority Critical patent/EP4024801A4/en
Publication of WO2021047311A1 publication Critical patent/WO2021047311A1/zh
Priority to US17/691,480 priority patent/US11902054B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0204—Channel estimation of multiple channels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0226—Channel estimation using sounding signals sounding signals per se
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/024—Channel estimation channel estimation algorithms
    • H04L25/0242—Channel estimation channel estimation algorithms using matrix methods
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals
    • H04L27/2613—Structure of the reference signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2657—Carrier synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/024—Channel estimation channel estimation algorithms
    • H04L25/0242—Channel estimation channel estimation algorithms using matrix methods
    • H04L25/0244—Channel estimation channel estimation algorithms using matrix methods with inversion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/024—Channel estimation channel estimation algorithms
    • H04L25/0242—Channel estimation channel estimation algorithms using matrix methods
    • H04L25/0246—Channel estimation channel estimation algorithms using matrix methods with factorisation

Definitions

  • This application relates to the field of communications, and more specifically, to a method, station, and access point for uplink multi-site channel estimation.
  • uplink multiple-user multiple input multiple output (UL MU-MIMO) technology is introduced, and multiple uplink stations (stations, STAs) are connected to the access point (access point, AP) sends data at the same time.
  • UL MU-MIMO uplink multiple-user multiple input multiple output
  • the sites are of different types, and the radio frequency links of the sites are different. Therefore, the carrier frequency used by the sites when sending data is difficult to be consistent, that is, multiple sites cannot achieve frequency synchronization.
  • the AP side performs channel estimation, it is difficult for the channels of multiple stations to be orthogonal and crosstalk with each other, which greatly reduces the accuracy of channel estimation. Therefore, how to improve the estimation accuracy of the channel information of multiple stations in the scenario of multiple-input and multiple-output uplink multi-site channels has become an urgent problem to be solved.
  • This application provides a method, a station, and an access point for uplink multi-site channel estimation.
  • Multiple stations send frames including two sets of training sequences to the access point.
  • the two sets of training sequences can improve the solution of the station and the access point.
  • the accuracy of the frequency offset value between the two can improve the accuracy when the access point performs channel estimation based on the frequency offset value.
  • a method for uplink multi-site channel estimation is provided, which is applied to any one STA of a plurality of station STAs communicating with an access point AP, including: the station STA generates a frame, and the frame includes the first Set of training sequences and a second set of training sequences, the first set of training sequences and the second set of training sequences are used to solve the frequency offset value between the STA and the access point AP, and the frequency offset value is used for channel estimation; The AP sends the frame.
  • the STA In the method for uplink multi-site channel estimation provided by the embodiment of the present application, the STA generates a frame including a first set of training sequences and a second set of training sequences, and sends the generated frames to the AP.
  • the two sets of training sequences can improve the accuracy of solving the frequency offset value between the STA and the AP, and thus can improve the accuracy when the AP performs channel estimation based on the frequency offset value.
  • the method before the STA generates the frame, the method further includes: the STA receives indication information from the AP, and the indication information is used to instruct the STA to generate the frame.
  • the AP may send instruction information to the STA to instruct the STA to generate a frame including the first set of training sequences and the second set of training sequences.
  • the indication information is also used to indicate whether the STA generates the frame using a preset phase identification matrix, and/or the indication information is also used to indicate the The arrangement of the first set of training sequences and the second set of training sequences in the frame.
  • the above-mentioned indication information may also be used to indicate whether to add a phase identifier when the STA generates a frame, and/or instruct the STA to combine the above-mentioned first set of training sequences with the second
  • the arrangement of group training sequences in the frame provides an alternative way for the structure of the frame generated by the STA.
  • the first set of training sequences is obtained by multiplying the preset training sequence by the element corresponding to the STA in the P matrix
  • the second set of training sequences is obtained by the preset training
  • the sequence is obtained by multiplying the P matrix or the element corresponding to the STA in the P1 matrix, where the P1 matrix is a matrix determined based on a preset phase identification matrix, and the P matrix is known to the AP and the multiple STAs for The matrix of channel estimation.
  • the method for uplink multi-site channel estimation provided by the embodiment of the application can determine the above-mentioned first set of training sequences and second set of training sequences based on the P matrix or the P1 matrix, so as to obtain the first set of training sequences and the second set of training sequences. Plan.
  • the first set of training sequences occupies Q first positions in the frame
  • the second set of training sequences occupies Q second positions in the frame
  • the Q first positions and the Q second positions are arranged in sequence; or, the Q first positions and Q second positions are arranged at equal intervals, and the Q is the one that satisfies the preset correspondence relationship with M
  • M is the total number of antennas of the multiple STAs.
  • the positions of the first training sequence and the second training sequence in the frame have multiple possibilities, and they are the difference between the first training sequence and the second training sequence.
  • the arrangement provides a flexible scheme.
  • the foregoing first set of training sequences includes one or more first training sequences
  • the foregoing second set of training sequences includes one or more second training sequences. sequence.
  • the above-mentioned first set of training sequences and the second set of training sequences may respectively include at least one training sequence.
  • a method for uplink multi-site channel estimation includes: an access point AP receives frames sent by multiple STAs, and the frame includes a first set of training sequences and a second set of training sequences. The set of training sequences and the second set of training sequences are used to calculate the frequency offset values between the STA and the access point AP; the AP performs channel estimation based on the frequency offset values between the M STAs and the AP.
  • an AP receives frames including a first set of training sequences and a second set of training sequences from multiple STAs.
  • the two sets of training sequences can improve the accuracy of solving the frequency offset value between the STA and the AP, and thus can improve the accuracy when the AP performs channel estimation based on the frequency offset value.
  • the AP sends instruction information to the STA, and the instruction information is used to instruct the STA to generate the frame.
  • the AP may send instruction information to the STA to instruct the STA to generate a frame including the first set of training sequences and the second set of training sequences.
  • the indication information is also used to indicate whether the STA generates the frame using a preset phase identification matrix, and/or the indication information is also used to indicate the The arrangement of the first set of training sequences and the second set of training sequences in the frame.
  • the above-mentioned indication information may also be used to indicate whether to add a phase identifier when the STA generates a frame, and/or instruct the STA to combine the above-mentioned first set of training sequences with the second
  • the arrangement of group training sequences in the frame provides an alternative way for the structure of the frame generated by the STA.
  • the first set of training sequences is obtained by multiplying the preset training sequence by the element corresponding to the STA in the P matrix
  • the second set of training sequences is obtained by the preset training
  • the sequence is obtained by multiplying the elements of the P matrix or the P1 matrix corresponding to the STA, where the P1 matrix is a matrix determined based on a preset phase identification matrix, and the P matrix is a known channel used by the AP and the multiple STAs. Estimated matrix.
  • the method for uplink multi-site channel estimation provided by the embodiment of the present application can determine the above-mentioned first set of training sequences and second set of training sequences based on the P matrix or the P1 matrix, and provide for obtaining the first set of training sequences and the second set of training sequences.
  • a feasible solution can determine the above-mentioned first set of training sequences and second set of training sequences based on the P matrix or the P1 matrix, and provide for obtaining the first set of training sequences and the second set of training sequences.
  • the use of the first set of training sequences and the second set of training sequences to calculate the frequency offset value between the STA and the access point AP includes: the multiple STAs respectively send The multiple first sets of training sequences and channel information matrices in the STA are used to determine the first information matrix; the multiple second sets of training sequences and channel information matrices sent by the multiple STAs are used to determine the second information matrix; the first information matrix And the second information matrix are used to calculate the frequency offset values between the multiple STAs and the AP.
  • the first set of training sequences and the second set of training sequences included in the training sequences sent by each STA are respectively sent to the AP through the channels between the STAs and the AP.
  • the AP can receive the first information matrix and the second information matrix, and based on the first information matrix and the second information matrix, solve the frequency offset values between the M STAs and the AP, and determine the frequency offset for the AP Value provides feasible solutions.
  • the AP performs channel estimation based on the frequency offset values between the multiple STAs and the AP, including: the AP is based on the multiple STAs and the AP respectively.
  • the P matrix is corrected by the frequency offset value between the two to obtain a corrected P matrix; the AP determines the channel information matrix based on the first information matrix and/or the second information matrix, and the corrected P matrix.
  • the corrected P matrix is obtained based on the frequency offset value and the P matrix, and the corrected P matrix is obtained according to the corrected frequency offset value.
  • the P matrix and the aforementioned first information matrix and/or the second information matrix determine the channel information matrix to complete the channel estimation.
  • the first set of training sequences occupies Q first positions in the frame
  • the second set of training sequences occupies Q second positions in the frame
  • the Q first positions and the Q second positions are arranged in sequence; or, the Q first positions and Q second positions are arranged at equal intervals
  • the Q is the one that satisfies the preset correspondence relationship with M
  • M is the total number of antennas of the multiple STAs.
  • the positions of the first set of training sequences and the second set of training sequences in the frame have multiple possibilities, which are the difference between the first set of training sequences and the second set of training sequences.
  • the arrangement provides a flexible scheme.
  • the foregoing first set of training sequences includes one or more first training sequences
  • the foregoing second set of training sequences includes one or more second training sequences. sequence.
  • the above-mentioned first set of training sequences and the second set of training sequences may respectively include at least one training sequence.
  • a method for uplink multi-site channel estimation is provided, which is applied to any STA among multiple STAs communicating with an access point AP, including: the STA generates a frame, and the frame includes a first set of training Sequence and a second set of training sequences, the first set of training sequences includes Q first training sequences, and the second set of training sequences includes Q second training sequences; the STA sends the frame to the AP, where Q It is an integer that satisfies the preset correspondence relationship with M, and M is the total number of antennas of multiple STAs.
  • the Q first training sequences are the same as the Q second training sequences, respectively.
  • the Q second training sequences are the training sequences obtained by adding phase identification information to the Q first training sequences.
  • Q first training sequences and Q second training sequences are sequentially arranged in the aforementioned frame; or, Q first training sequences and Q second training sequences The training sequences are arranged alternately at the same interval in the above-mentioned frames.
  • a method for uplink multi-site channel estimation is provided, which is applied to an access point AP communicating with multiple STAs, including: the AP receives a frame from the STA, and the frame includes a first set of training sequences And a second set of training sequences, the first set of training sequences includes Q first training sequences, the second set of training sequences includes Q second training sequences; the AP is based on the first set of training sequences and the second set of training sequences
  • the training sequence performs channel estimation, where Q is an integer that satisfies a preset correspondence relationship with M, and M is the total number of antennas of multiple STAs.
  • the Q first training sequences are the same as the Q second training sequences, respectively.
  • the Q second training sequences are training sequences obtained by adding phase identification information to the Q first training sequences.
  • Q first training sequences and Q second training sequences are sequentially arranged in the aforementioned frame; or, Q first training sequences and Q second training sequences The training sequences are arranged alternately at the same interval in the above-mentioned frames.
  • an apparatus for uplink multi-site channel estimation includes a processor, configured to implement the functions of the STA in the methods described in the first and third aspects.
  • the apparatus for uplink multi-site channel estimation may further include a memory, the memory is coupled to the processor, and the processor is configured to implement the function of the STA in the methods described in the first aspect and the third aspect.
  • the memory is used to store program instructions and data.
  • the memory is coupled with the processor, and the processor can call and execute program instructions stored in the memory to implement the functions of the STA in the methods described in the first aspect and the third aspect.
  • the apparatus for uplink multi-site channel estimation may further include a communication interface, and the communication interface is used for the apparatus for uplink multi-site channel estimation to communicate with other devices.
  • the communication interface may be a transceiver, an input/output interface, or a circuit.
  • the device for uplink multi-site channel estimation includes: a processor and a communication interface,
  • the processor is configured to run a computer program, so that the device for uplink multi-site channel estimation implements any one of the methods described in the first aspect and the third aspect;
  • the processor communicates with the outside by using the communication interface.
  • the exterior may be an object other than the processor, or an object other than the device.
  • the device for uplink multi-site channel estimation is a chip or a chip system.
  • the communication interface may be an input/output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip or chip system.
  • the processor may also be embodied as a processing circuit or a logic circuit.
  • an apparatus for uplink multi-site channel estimation includes a processor, configured to implement the function of the AP in the methods described in the second and fourth aspects above.
  • the apparatus for uplink multi-site channel estimation may further include a memory, the memory is coupled to the processor, and the processor is configured to implement the function of the AP in the methods described in the second aspect and the fourth aspect.
  • the memory is used to store program instructions and data.
  • the memory is coupled with the processor, and the processor can call and execute the program instructions stored in the memory to implement the functions of the AP in the methods described in the second aspect and the fourth aspect.
  • the apparatus for uplink multi-site channel estimation may further include a communication interface, and the communication interface is used for the apparatus for uplink multi-site channel estimation to communicate with other devices.
  • the communication interface may be a transceiver, an input/output interface, or a circuit.
  • the device for uplink multi-site channel estimation includes: a processor and a communication interface,
  • the processor communicates with the outside by using the communication interface
  • the processor is configured to run a computer program, so that the device for uplink multi-site channel estimation implements any one of the methods described in the second aspect and the fourth aspect.
  • the exterior may be an object other than the processor, or an object other than the device.
  • the device for uplink multi-site channel estimation is a chip or a chip system.
  • the communication interface may be an input/output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip or chip system.
  • the processor may also be embodied as a processing circuit or a logic circuit.
  • the present application provides a computer-readable storage medium having instructions stored in the computer-readable storage medium, which when run on a computer, cause the computer to execute the methods described in the foregoing aspects.
  • this application provides a computer program product containing instructions, which when run on a computer, causes the computer to execute the methods described in the above aspects.
  • a communication system including the uplink multi-site channel estimation device shown in the fifth aspect and the uplink multi-site channel estimation device shown in the sixth aspect.
  • Figure 1 is a system schematic diagram of a typical WLAN deployment scenario.
  • FIG. 2 are schematic diagrams of uplink transmission between AP and STA in the MU-MIMO manner provided in an embodiment of the present application.
  • Fig. 3 is a schematic diagram of two STAs sending data to an AP according to an embodiment of the present application.
  • Fig. 4 is a schematic diagram of a single-antenna STA sending data according to an embodiment of the present application.
  • FIG. 5 is a schematic diagram of orthogonal sequences corresponding to multiple STAs provided in an embodiment of the present application.
  • FIG. 6 is a schematic flowchart of a method for uplink multi-site channel estimation provided by an embodiment of the present application.
  • FIG. 7 are schematic diagrams of frames provided in an embodiment of the present application.
  • FIG. 8 are schematic diagrams of frames generated by two STAs provided in an embodiment of the present application.
  • FIG. 9 is a schematic diagram of the device 90 for uplink multi-site channel estimation proposed in this application.
  • FIG. 10 is a schematic structural diagram of a STA 1000 applicable to an embodiment of the present application.
  • FIG. 11 is a schematic diagram of the apparatus 1100 for uplink multi-site channel estimation proposed in this application.
  • FIG. 12 is a schematic structural diagram of an AP 1200 applicable to an embodiment of the present application.
  • the embodiments of the present application may be applied to a wireless local area network (WLAN), and the WLAN may include multiple basic service sets (BSS).
  • the network nodes of the BSS include AP and STA.
  • Each BSS may include one AP and multiple STAs associated with the AP.
  • the above-mentioned AP may also be called a wireless access point or hotspot.
  • APs are the access points for user terminals to enter the wired network and are mainly deployed in homes, buildings, and campuses. A typical AP coverage radius is tens of meters to hundreds of meters. It should be understood that the AP can also be deployed outdoors.
  • AP is equivalent to a bridge connecting wired network and wireless network, and its main function is to connect the clients of each wireless network together, and then connect the wireless network to the Ethernet.
  • the main standards adopted by APs are the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series.
  • the AP may be a terminal device or a network device with a wireless fidelity (wireless fidelity, WiFi) chip.
  • the AP may be a device supporting the WLAN standard.
  • the STA refers to a user terminal in this application, so it may be directly referred to as a user terminal or a user in the following.
  • the STA can be a wireless communication chip, a wireless sensor, or a wireless communication terminal.
  • mobile phones that support WiFi communication functions
  • tablet computers that support WiFi communication functions
  • set-top boxes that support WiFi communication functions
  • smart TVs that support WiFi communication functions
  • smart wearable devices that support WiFi communication functions
  • computers that support WiFi communication functions.
  • the STA may be a device supporting the WLAN standard.
  • Figure 1 is a system schematic diagram of a typical WLAN deployment scenario, including an AP and 4 STAs.
  • the AP communicates with STA#1, STA#2, STA#3, and STA#4, respectively.
  • the uplink transmission methods between AP and STA include but are not limited to orthogonal frequency-division multiple access (OFDMA), multi-site channel multiple input multiple output (MU-MIMO) ) Mode or a hybrid transmission mode of OFDMA and MU-MIMO.
  • OFDMA orthogonal frequency-division multiple access
  • MU-MIMO multi-site channel multiple input multiple output
  • FIG. 2 is a schematic diagram of uplink transmission between an AP and a STA in an MU-MIMO manner according to an embodiment of the present application.
  • the AP in FIG. 2 includes N antennas (antenna #1 to antenna #N as shown in FIG. 2), and the total number of antennas of all STAs is M.
  • Fig. 2 h NM represents the channel between the antenna M on the STA side and the antenna N on the AP side.
  • Figure 2(a) shows that one STA may include multiple antennas. If there is a frequency difference between the STA and the AP, the signals emitted by the multiple antennas and the AP have the same frequency difference.
  • Figure 2(b) is the equivalent transformation of Figure 2(a), that is, a STA including multiple antennas can be equivalent to multiple identical single-antenna STAs. It should be understood that this equivalent transformation is only for easier understanding of this application The technical solution provided does not constitute any limit to the protection scope of this application.
  • used to indicate can include both used for direct indication and used for indirect indication.
  • the indication information may directly indicate A or indirectly indicate A, but it does not mean that A must be carried in the indication information.
  • the information indicated by the instruction information is called the information to be indicated.
  • the information to be indicated can be directly indicated, such as the information to be indicated or the information to be indicated. Indicates the index of the information, etc.
  • the information to be indicated can also be indicated indirectly by indicating other information, where there is an association relationship between the other information and the information to be indicated. It is also possible to indicate only a part of the information to be indicated, while other parts of the information to be indicated are known or agreed in advance. For example, it is also possible to realize the indication of specific information by means of the pre-arranged order (for example, stipulated by the agreement) of various information, thereby reducing the indication overhead to a certain extent. At the same time, it can also identify the common parts of each information and uniformly indicate, so as to reduce the instruction overhead caused by separately indicating the same information.
  • the first, second, and various digital numbers (for example, "#1", “#2”, etc.) shown in this application are only for convenience of description, and are used for distinguishing objects, and are not used to limit the text. Apply for the scope of the embodiment. For example, distinguish the first set of training sequences from the second set of training sequences, and so on. It is not used to describe a specific order or sequence. It should be understood that the objects described in this way can be interchanged under appropriate circumstances, so as to be able to describe solutions other than the embodiments of the present application.
  • pre-defined may include pre-defined, for example, protocol definition.
  • pre-defined can be implemented by pre-saving corresponding codes, tables, or other methods that can be used to indicate related information in the device (for example, including STA and AP), and this application does not limit the specific implementation manner.
  • the "saving" involved in the embodiments of the present application may refer to storing in one or more memories.
  • the one or more memories may be provided separately, or integrated in an encoder or decoder, a processor, or a communication device.
  • the one or more memories may also be partly provided separately, and partly integrated in a decoder, a processor, or a communication device.
  • the type of the memory can be any form of storage medium, which is not limited in this application.
  • the “protocols” involved in the embodiments of this application may refer to standard protocols in the communication field, such as WiFi protocol, new radio (NR) protocol, and related protocols applied to future communication systems.
  • the application is not limited.
  • h ij the channel between the antenna of STA#j and the AP-side antenna #i, i and j are positive integers.
  • AP side antenna #k receives the data size on the lth symbol, and k and l are positive integers; Information received by the AP-side antenna #i on the sub-carrier k of the j-th symbol (this application takes one sub-carrier as an example for description).
  • P fix P matrix corrected based on the frequency offset value between STA and AP.
  • STA#h The size of the data sent on the i-th symbol.
  • the uplink multi-site MIMO mainly relies on the multi-antenna orthogonal equalization on the AP side, that is, the AP side uses the training sequence to obtain the link information of the air interface (for example, wireless channel state information (CSI)), and then balance the multiple antennas.
  • the effective load of the site splits the superimposed information of multiple sites so that each site is orthogonal to each other and does not affect each other. Therefore, whether the wireless channel state information can be accurately obtained, on the one hand, will directly affect the orthogonality of the uplink multi-site, or it is the key to the accuracy of each site to obtain their respective streams; on the other hand, it may also affect the access point during the downlink data transmission. Precoding accuracy.
  • the process of obtaining wireless channel state information can also be referred to as channel estimation.
  • Fig. 3 is a schematic diagram of two STAs sending data to an AP according to an embodiment of the present application.
  • Fig. 3 includes two STAs (STA#1 and STA#2 as shown in Fig. 3) and an AP.
  • STA#1 and STA#2 can access the network through the AP.
  • STA#1 and STA#2 can be two mobile phones that support WiFi communication
  • the AP can be a router with a WiFi chip
  • the AP has two antennas (antenna #1 and antenna #2 shown in Figure 3). ).
  • CFO carrier frequency offset
  • the data sent by STA#1 is Then through the spatial channels h 11 and h 21 , they reach antenna #1 and antenna #2 on the AP side respectively;
  • the data sent by STA#2 is Then, through the spatial channels h 12 and h 22 , they reach antenna #1 and antenna #2 on the AP side, respectively.
  • the data received by antenna #1 and antenna #2 on the AP side are superimposed signals of two STAs after passing through the air interface channel.
  • the data received by antenna #1 includes with among them
  • the data received by antenna #2 includes with among them
  • the data sent by the STA involved in the embodiment of this application can be understood as a long training field (LTF) sent by the STA on a certain subcarrier, and the data in this application can also be understood as a signal.
  • LTF long training field
  • the AP side only needs to perform simple mathematical operations on the received data to obtain h 11 , h 21 , h 12 and h 22 to obtain the CSI.
  • the above process can be expressed in a matrix way, which is more conducive to understanding.
  • the data received at the AP is expressed as the following formula:
  • STA#1 and STA#2 have their own frequency offsets from the AP.
  • the frequency offset of STA#1 relative to the AP is ⁇ f 1
  • the frequency offset of STA#2 relative to the AP is ⁇ f 2 .
  • the data received at the AP is expressed as the following formula:
  • the data sent by the two STAs corresponds to the P matrix by default Because the AP side does not know that the STA has a frequency offset, the AP follows the original operation and obtains:
  • the channel of one STA of the two STAs is doped with the channel of the other STA, and mutual crosstalk occurs. It can be seen from the above calculation process that it is caused by the non-orthogonality of the P matrix, that is to say, if the frequency offset information of the STA can be obtained on the AP side, the P matrix on the AP side can be compensated or modified so that the P matrix is not the above But consider the P fix matrix after frequency offset information Then, based on the matrix P fix , the inverse channel is solved, and then accurate channel information can be obtained.
  • the AP when there is a frequency offset between the STA and the AP, the AP cannot accurately obtain the channel information between the STA and the AP based on the original P matrix.
  • the P In order to obtain accurate channel information, the P must first be obtained. fix matrix, and the key to obtaining the P fix matrix is to know the frequency offset value between the STA and the AP, and the P fix matrix can be obtained by correcting or compensating the P matrix based on the frequency offset value.
  • FIG. 4 is a schematic diagram of a single-antenna STA sending data according to an embodiment of the present application.
  • the data received by the AP side is the superposition of data sent by multiple STAs when sending data from multiple STAs in the uplink, the information cannot be distinguished. Even if repeated data is sent, the data on the two symbols are all multi-STA data. Therefore, the frequency offset value of each STA cannot be accurately estimated, and the STA channels cannot be orthogonalized, resulting in crosstalk between STAs.
  • the channels in consecutive orthogonal blocks of sub-carriers are almost equal, that is, the channels are relatively flat channels.
  • Different orthogonal sequences are assigned to the subcarriers sent by each STA, so that the AP side can unpack the channel information of each STA, and then obtain the phase rotation angle between symbols.
  • FIG. 5 is a schematic diagram of orthogonal sequences corresponding to multiple STAs provided in an embodiment of the present application.
  • STA#1 the data sent by each subcarrier of the first symbol
  • STA#2 the data sent by each subcarrier of the first symbol is Because the subcarriers sent by each STA are allocated orthogonal sequences, so:
  • each subcarrier of the first symbol can be expressed as:
  • the AP side can perform the same processing as described above to obtain:
  • this application provides a method for uplink multi-site channel estimation. By sending multiple groups of training sequences for channel estimation, the accuracy of channel estimation is improved.
  • the method provided in the embodiment of the present application may be applied to a WLAN communication system, for example, the communication system 100 shown in FIG. 1.
  • the communication system may include at least one AP and multiple STAs.
  • the frequency offsets between the multiple STAs and the AP are inconsistent.
  • a single-antenna STA is taken as an example for description, that is, an AP is associated with multiple single-antenna STAs.
  • the frequency offset between each antenna and the antenna of the AP is similar, so the calculation method of the channel information between other antennas on the STA and the antenna of the AP can refer to the embodiments of this application.
  • the calculation method of the channel information between a certain antenna of the STA and the antenna of the AP involved in this application will not be repeated in this application.
  • the method for uplink multi-site channel estimation can also be applied in the scenario of multiple APs.
  • the system of the WLAN deployment scenario shown in FIG. 1 also includes another AP.
  • the communication between the AP and the STA is similar to the AP shown in FIG. 1.
  • the channel estimation between the other AP and the STA can refer to the channel estimation between the AP and the STA shown in FIG. Go into details.
  • the data transmission between the STA and the AP can take place over the full bandwidth (for example, a 20M bandwidth, including 256 subcarriers).
  • the channel estimation between the STA and the AP on one subcarrier is An example is described, and other sub-carriers are similar, which will not be repeated in this application.
  • the embodiments shown below do not specifically limit the specific structure of the execution body of the method provided by the embodiments of the present application, as long as the program that records the code of the method provided by the embodiments of the present application can be executed according to the present application.
  • the method provided in the application embodiment only needs to communicate.
  • the execution subject of the method provided in the embodiment of the application may be an AP or STA, or a functional module in the AP or STA that can call and execute the program.
  • FIG. 6 is a schematic flowchart of a method for uplink multi-site channel estimation provided by an embodiment of the present application.
  • the executive body includes AP and STA.
  • STA For ease of understanding, only one STA is shown in FIG. 6. Actually, there are multiple STAs associated with the AP shown in FIG. 6 in the embodiment of the present application, which are not shown in the figure.
  • the method for uplink multi-site channel estimation includes some or all of the following steps.
  • the STA generates a frame.
  • the frame includes a first set of training sequences and a second set of training sequences, and the first set of training sequences and the second set of training sequences are used to calculate the frequency offset value between the STA and the access point AP.
  • the frequency offset value obtained by the solution can be used for channel estimation.
  • the frames involved in this application may be data frames, control frames, and so on.
  • the present application does not limit the type of the frame, as long as it includes the first set of training sequences and the second set of training sequences mentioned above.
  • the two groups of training sequences included in the frame are called the first set of training sequences and the second set of training sequences are just examples, and do not constitute any limitation on the protection scope of the present application.
  • it can also be referred to as the first training sequence block and the second training sequence block, the first training sequence set and the second training sequence set, and so on.
  • the first set of training sequences includes one or more first training sequences
  • the second set of training sequences includes one or more second training sequences.
  • the frame in the embodiment of the present application may further include more than two training sequence groups, for example, it may further include a third group of training sequences and a fourth group of training sequences. No more examples here.
  • the STA is any one of multiple STAs associated with the AP. It should be understood that the frequency offset values between the multiple STAs and the AP are different, and each STA of the multiple STAs generates its own training sequence and carries the training sequence in the frame.
  • the foregoing first set of training sequences is obtained by multiplying the preset training sequence by the element corresponding to the STA in the P matrix
  • the foregoing second set of training sequences is obtained by multiplying the preset training sequence by the P matrix or P1 matrix
  • the element corresponding to the STA in is obtained, where the P1 matrix is a matrix determined based on a preset phase identification matrix, and the P matrix is a matrix known by the AP and the multiple STAs for channel estimation.
  • the STA receives instruction information sent by the AP, and the instruction information is used to instruct the STA to generate the aforementioned frame. Then, the method flow shown in FIG. 6 further includes S611, where the AP sends instruction information to multiple STAs respectively.
  • the AP communicates with two STAs (STA#1 and STA#2).
  • the AP sends instruction information #1 to STA#1.
  • the instruction information #1 is used to instruct the STA#1 to generate frame #1.
  • the two sets of training sequences included in the frame #1 are used to estimate the channel from STA#1 to the AP.
  • AP sends instruction information #2 to STA#2
  • the instruction information #2 is used to instruct the STA#2 to generate frame #2
  • the two sets of training sequences included in the frame #2 are used to estimate the distance between STA#1 and the AP channel.
  • the indication information #1 and the indication information #2 can be the same piece of information, but the receiving end is different.
  • the indication information may be included in a repeat channel estimation announcement (RCEA) announcement frame.
  • RCEA repeat channel estimation announcement
  • the RCEA frame may be a newly defined frame, or the RECA frame may multiplex a trigger frame specified in the current protocol.
  • the name of the frame that includes the indication information is not limited in the embodiments of the present application, and may be referred to as the above-mentioned RCEA, or may be other names, and will not be illustrated one by one here.
  • the RCEA frame contains 1 bit of indication information, bit 0 indicates that the channel estimation method specified in the current protocol is used, and bit 1 indicates that the channel estimation training sequence using Re-CE is used, and the 1 bit of indication information is in the RCEA
  • the frame can be called the Re-CE field.
  • the definition of the Re-CE domain is shown in Table 1.
  • bit 1 indicates that the channel estimation method specified in the current protocol is used, and bit 0 indicates that the channel estimation training sequence of Re-CE is used;
  • the RECA frame includes 2 bits of indication information, for example, 00 and 11 indicate the channel estimation method specified by the current protocol, and 01 and 10 indicate the channel estimation training sequence using Re-CE;
  • the RECA frame includes indication information of more than 2 bits, and this application will not illustrate them one by one.
  • one bit of indication information may be included in the RCEA frame.
  • the reference to the frame carrying the indication information as the RCEA frame in this application is just an example, and does not constitute any limitation to the protection scope of this application.
  • it may also be called a trigger frame, an announcement frame, an indication frame, etc., and it may include the above indication information.
  • the above-mentioned indication information may also be used to indicate whether the STA uses a preset phase identification matrix during frame generation.
  • the above-mentioned RCEA frame also contains 1-bit indication information, bit 0 indicates that the preset phase identification matrix is used, and bit 1 indicates that the preset phase identification matrix is not used.
  • the foregoing indication information may also be used to indicate the arrangement of the first set of training sequences and the second set of training sequences generated by the STA in the foregoing frame.
  • the aforementioned RCEA frame also contains 1 bit of indication information, bit 0 indicates that the first set of training sequences and the second set of training sequences are arranged adjacent to each other in the above frame, and bit 1 indicates that the first set of training sequences and the first set of training sequences are arranged adjacent to each other in the frame.
  • the two sets of training sequences are alternately arranged at intermediate intervals in the aforementioned frames.
  • the aforementioned RCEA frame also contains 2 bits of indication information, where one bit (the first bit) of the 2 bits is used to indicate the arrangement of the first group of training sequences and the second group of training sequences in the aforementioned frame.
  • the first bit value of 0 indicates that the first set of training sequences and the second set of training sequences are arranged adjacent to each other in the aforementioned frame
  • the first bit value of 1 indicates that the first set of training sequences and the second set of The training sequence is interleaved at intermediate intervals in the aforementioned frames.
  • the other bit (the second bit) in the 2bit is used to indicate the number of equal intervals when the first set of training sequences and the second set of training sequences are interleaved at the same interval in the aforementioned frame.
  • a second bit value of 0 indicates that the interval at which the first set of training sequences and the second set of training sequences are interleaved at the aforementioned frame interval is 1; optionally, a second bit value of 1 indicates that the first set of training sequences The interval between the second set of training sequences and the second set of training sequences is 2 interleaved at the same interval in the aforementioned frame.
  • the above instructions indicate whether to generate frames, indicate whether to use the preset phase recognition matrix, indicate the first set of training sequences, the arrangement of the second set of training sequences in the above frames, and the first set of training sequences and the second set of training
  • the indication information of the interval interleaved in the sequence at equal intervals can be sent separately.
  • the AP sends the first indication information, the second indication information, the third indication information, and the fourth indication information to the STA, where the first indication information is used to indicate whether The generated frame, the second indication information is used to indicate whether to use the preset phase recognition matrix, the third indication information is used to indicate the first set of training sequences and the second set of training sequences, and the fourth indication information is used to indicate the first set of training
  • This application does not limit the order in which the first instruction information, the second instruction information, and the third instruction information are sent.
  • the AP can use the above-mentioned method to complete the content that needs to be indicated with a piece of instruction information.
  • the STA After receiving the above-mentioned RCEA frame, the STA checks the Re-CE field in the RCEA frame to determine whether the Re-CE training sequence needs to be used to complete the channel estimation process. Optionally, if the Re-CE field bit information is 1, the STA decides to generate the aforementioned frame including the first set of training sequences and the second set of training sequences; optionally, if the Re-CE field bit information is 0, then The STA decides to complete the channel estimation based on the known P matrix without generating the aforementioned frames.
  • the STA generating the aforementioned frame includes:
  • a single-antenna STA is taken as an example for description.
  • the STA checks which STA it belongs to and how many STAs there are in total.
  • the total number of antennas M of multiple STAs (because a single antenna is used as an example, the total number of antennas M can be understood as the total number of STAs M) is used to determine the dimension of the P matrix and the first and second training sequences respectively The number of training sequences included Q.
  • the embodiments of the present application do not limit the STA to be a single-antenna STA.
  • the single-antenna STA generating the aforementioned frame should be understood as the STA with multiple antennas generating the frame corresponding to the antenna.
  • STA#1 has two antennas (antenna #1 and antenna #2), and STA#2 has two antennas (antenna #3 and antenna #4), then STA#1 generates antenna #1 and antenna #2 respectively corresponding to STA#2 generates frame #3 and frame #4 corresponding to antenna #3 and antenna #4, respectively.
  • STA#1 determines that antenna #1 belongs to the first antenna, and there are a total of 4 antennas, and when STA#1 generates frame #2 corresponding to antenna #2, STA# 1 Make sure that antenna #2 belongs to the second antenna, and there are 4 antennas in total.
  • STA#1 is equivalent to STA#1_1 (with antenna #1), STA#1_2 (with antenna #2), STA#2 is equivalent to STA#2_1 (with antenna #3), STA #2_2 (with antenna #4), where STA#1_1 generates frame #1 corresponding to antenna #1, STA#1_2 generates frame #2 corresponding to antenna #2, and STA#2_1 generates frame #3 corresponding to antenna #3. STA#2_2 generates frame #4 corresponding to antenna #4.
  • STA#1_1 generates frame #1 corresponding to antenna #1
  • STA#1_1 determines that STA#1_1 belongs to the first STA, and there are 4 STAs in total.
  • a single-antenna STA is taken as an example for description, that is, the total number of antennas M is equal to the total number of STAs, and the order of a certain antenna in the total antenna is the order of the single-antenna STA with that antenna in the total STA. .
  • M shown in Table 2 can be the total number of antennas of multiple STAs, but it should be understood that this application is not limited to the total number of antennas of multiple STAs.
  • M can also be understood as the total number of antennas of multiple STAs. Or a certain value determined based on the total number of antennas of the multiple STAs.
  • the ranking of the STA in the total STA is used to determine the training sequence in the first set of training sequences and the second set of training sequences of the STA, which is obtained by multiplying the preset training sequence by the element of the P matrix. among them.
  • the preset training sequence may be obtained by orthogonally extending the long training sequence (LTS) or LTF in the preamble of the existing data frame in the frequency domain.
  • LTS long training sequence
  • Each STA has its own spreading sequence, and the spreading sequences of each STA are orthogonal to each other.
  • the orthogonal extension of the pair of long training sequences can use a Walsh matrix or an existing P matrix, etc., as long as the orthogonality is satisfied.
  • a 4 ⁇ 4 matrix is selected for the P matrix, and 4 training sequences in the first group of training sequences are required.
  • the 4 training sequences are respectively multiplied by the 4 elements corresponding to the first row of the P matrix to obtain the first set of training sequences.
  • the second to fourth STAs among the four STAs can be deduced by analogy, and details are not repeated here.
  • the 4 STAs can also be regarded as two STAs with two antennas respectively. At this time, a 4 ⁇ 4 matrix is still selected for the P matrix, and 4 training sequences in the first group of training sequences are required.
  • the four training sequences are respectively multiplied by the four elements corresponding to the first row of the P matrix to obtain the first set of training sequences.
  • the second to fourth antennas of the four antennas can be deduced by analogy, and the case where a certain STA has multiple antennas will not be described in detail below.
  • the second set of training sequences can be processed in the same way, and then the generated first set of training sequences and the second set of training sequences are arranged in a frame in a certain order and sent to the AP.
  • the first set of training sequences generated by STA#1 includes Q training sequences (preset training sequence ⁇ P 11 , preset training sequence ⁇ P 12 , ..., preset training sequence ⁇ P 1Q );
  • the second set of training The sequence includes Q training sequences (preset training sequence ⁇ P 21 , preset training sequence ⁇ P 22 , ..., preset training sequence ⁇ P 2Q ).
  • the first set of training sequences occupies Q first positions in the frame, and the second set of training sequences occupies Q second positions in the frame.
  • the above-mentioned Q first positions and Q second positions are sequentially arranged in the frame. That is, the first set of training sequences and the second set of training sequences generated by the STA are sequentially arranged adjacent to each other in the frame, as shown in FIG. 7(a), which is a schematic diagram of a frame provided by an embodiment of the present application;
  • the foregoing Q first positions and Q second positions are arranged crosswise and adjacent to each other in the frame. That is, the training sequences included in the first set of training sequences and the second set of training sequences generated by the STA are arranged in a cross-adjacent frame, as shown in FIG. 7(b). It can be seen from FIG. 7(b) that the Q training sequences included in the first set of training sequences and the Q training sequences included in the second set of training sequences are arranged one by one at an interval.
  • the foregoing Q first positions and Q second positions are arranged alternately at an even interval in the frame. That is, the first set of training sequences generated by the STA and the training sequences included in the second set of training sequences are alternately arranged in the frame at equal intervals, as shown in FIG. 7(c). It can be seen from FIG. 7(b) that the Q training sequences included in the first set of training sequences and the Q training sequences included in the second set of training sequences are arranged at two intervals.
  • a first position and a second position may be alternately arranged as shown in FIG. 7(b), or The two first positions and the two second positions can be arranged crosswise as shown in FIG. 7(c), and the N first positions and N second positions can be crosswise arranged (N is less than Q), which will not be repeated in this application.
  • the first set of training sequences and the second set of training sequences are alternately arranged at equal intervals.
  • the specific interval manner can be designed based on the frequency offset values of different STAs that can be identified from the AP side.
  • phase identification information may be added to the above-mentioned second set of training sequences. That is, the second set of training sequences is obtained by multiplying the preset training sequence by the element corresponding to the STA in the P1 matrix.
  • the P1 matrix is a matrix obtained by multiplying the preset phase identification matrix by the P matrix.
  • the P1 matrix is a preset phase identification matrix with a phase identification function.
  • STA#1 receives RCEA frame #1 sent by AP, and determines that frame #1 needs to be generated according to the bit value of the Re-CE field in RCEA frame #1 (for example, the bit value is 1).
  • STA#1 learns that STA#1 is the first STA according to the information in RCEA frame #1, and that there are currently two STAs that will simultaneously uplink MU-MIMO. It should be understood that in the embodiments of this application, there is no limitation on how the STA learns the total number of MU-MIMO uplink STAs at the same time and the order in which it is located in the total STA. It can follow the current protocol or use the future The solution after the development of WiFi technology.
  • the first set of training sequences generated by STA#1 should include two training sequences, and the dimension of the P matrix is 2.
  • the P matrix is The two training sequences are respectively multiplied by the two elements in the first row of the P matrix, that is, multiplied by [1 -1].
  • the first training sequence in the two training sequences is multiplied by 1, and the second training sequence in the two training sequences is multiplied by -1;
  • STA#1 generates the second set of training sequences in the same process as the first set of training sequences described above Similar, I won't repeat it here.
  • STA#2 receives RCEA frame #2 sent by AP, and determines that frame #2 needs to be generated according to the bit value of the Re-CE field in RCEA frame #2.
  • STA#2 learns that STA#2 is the second STA according to the information in RCEA frame #2, and that there are currently two STAs that will simultaneously uplink MU-MIMO.
  • the first set of training sequences generated by STA#2 should include two training sequences, and the dimension of the P matrix is 2.
  • the P matrix is The two training sequences are respectively multiplied by the two values in the second row of the P matrix, that is, multiplied by [1 1].
  • the first training sequence of the two training sequences is multiplied by 1
  • the second training sequence of the two training sequences is multiplied by 1.
  • the process of STA#2 generating the second set of training sequences is similar to the above-mentioned generating the first set of training sequences , I won’t repeat it here.
  • FIG. 8 is a schematic diagram of a frame generated by two STAs provided in an embodiment of the present application.
  • the first set of training sequences generated by STA#1 and the training sequences included in the second set of training sequences are alternately arranged in the frame to be sent; the first set of training sequences and the first set of training sequences generated by STA#2
  • the training sequences included in the two sets of training sequences are alternately arranged in the frame to be sent, as shown in Figure 8(b).
  • phase identification information can be added to the second set of training sequences.
  • the phase identification matrix P Phase_identify is introduced,
  • the P Phase_identify can be generated based on the P matrix, for example:
  • the STA sends the first set of training sequences and the second set of training sequences to the AP. Specifically, the STA sends a frame to the AP, and the frame includes the generated first set of training sequences and the second set of training sequences, that is, the method flow shown in FIG. 6 further includes S620, where the STA sends the frame to the AP.
  • the STA sends the aforementioned frame to the AP after a specified time interval
  • M STAs send frames at the same time
  • the frames sent by each STA include the first set of training sequences and the second set of training sequences generated by the STA.
  • this application does not limit the prescribed time interval.
  • the foregoing M STAs respectively send frames to the AP, and the respective frames sent include the first set of training sequences and the second set of training sequences generated respectively. It can be seen from FIG. 7 that the first set of training sequences and the second set of training sequences generated by the STA include multiple different emission modes in the frame. Then the frame received by the AP includes multiple possible forms as shown in FIG. 7.
  • the M first set of training sequences included in the M frames respectively sent by the M STAs are sent to the AP through the channels between the M STAs and the AP respectively, and the first information matrix received by the AP side is the same;
  • the M second group training sequences included in the M frames respectively sent by the M STAs are sent to the AP through the channels between the M STAs and the AP, and the AP receives the second information matrix.
  • the first information matrix and the second information matrix are used to solve the frequency offset values between the M STAs and the AP, respectively.
  • the foregoing first information matrix may be expressed as the product of a training sequence matrix composed of M first group training sequences and a channel information matrix composed of channel information between M STAs and the AP;
  • the second information matrix of may be expressed as a product of a training sequence matrix composed of M second sets of training sequences and a channel information matrix composed of channel information between M STAs and the AP.
  • the matrix formed by the channel information between the M STAs and the AP is referred to as a channel information matrix, which is only an example, and does not constitute any limitation on the protection scope of the present application.
  • a channel information matrix which is only an example, and does not constitute any limitation on the protection scope of the present application.
  • it can also be called a channel estimation matrix, a channel matrix, and so on.
  • the AP can calculate the frequency offset values between the M STAs and the AP respectively, that is, the method flow shown in FIG. 6 also includes S630, where the AP calculates the frequency offset value.
  • the AP calculates the frequency offset value including the following possible situations:
  • the embodiments of the present application mainly consider different frequency offsets between STAs and APs.
  • the frequency offsets between M STAs and APs are ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M
  • the training sequence sent by each STA in the M STAs will be due to the frequency offset.
  • the training sequence sent on the symbol will generate phase rotation accumulation relative to the training sequence sent on the first symbol, so the phase rotation angle of the training sequence sent on a certain symbol Q relative to the training sequence sent on the first symbol is j2 ⁇ f(Q-1)T.
  • the first information matrix is expressed as:
  • the eigenvalue can be obtained by solving : The frequency offset values between the M STAs and the AP are calculated based on the above eigenvalues to be ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M, respectively .
  • the frames sent by the M STAs received by the AP are shown in Figure 7(a), and in S610, the STAs generate the second set of training sequences based on the P1 matrix.
  • the above-mentioned first information matrix may be expressed as the above-mentioned formula 1-1.
  • the embodiments of the present application mainly consider different frequency offsets between STAs and APs.
  • the frequency offsets between M STAs and APs are ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M
  • the training sequence sent by each STA in the M STAs will be due to the frequency offset.
  • the training sequence sent on the symbol will generate phase rotation accumulation relative to the training sequence sent on the first symbol, so the phase rotation angle of the training sequence sent on a certain symbol Q relative to the training sequence sent on the first symbol is j2 ⁇ f(Q-1)T.
  • the first information matrix represents the above formula 1-2.
  • the second set of training sequences is obtained by multiplying the preset training sequence by the P1 matrix, so the second information matrix is expressed as:
  • Equation 1-7 After the first information matrix is inverted, the result obtained by multiplying the second information matrix to the left has standard eigenvalue decomposition properties, which can be obtained by using eigenvalue decomposition
  • the eigenvalue can be obtained by solving: The frequency offset values between the M STAs and the AP are calculated based on the above eigenvalues to be ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M, respectively .
  • the eigenvalues may be sorted from large to small, so that it is impossible to distinguish the STA corresponding to each eigenvalue, so by adding the phase recognition angle, you can calculate the Calculate the angle from the eigenvalues, and get the angle value corresponding to each eigenvalue.
  • the latest 802.11ax protocol requires the STA to achieve frequency offset pre-compensation within 350Hz, that is to say, the frequency offset value between the STA and the AP will not exceed 350Hz, and a symbol is normally 16us.
  • the basically obtained angle value (if the phase recognition angle is not included) is 2 ⁇ f 1 2T ⁇ 4.032 degrees.
  • the eigenvalue that is closest to the 90 degree value is the eigenvalue corresponding to STA#1.
  • the phase recognition angle of 180 degrees is added to STA#2, the eigenvalue that is closest to the value of 180 degrees will be found in the obtained eigenvalue angle value. It is the characteristic value corresponding to STA#2. It should be understood that this application does not limit how to set the phase recognition angle, and it can be set as required. In this way, the phase rotation angles of STA#1 and STA#2 can be simply obtained.
  • the frames sent by M STAs received by the AP are as shown in Figure 7(b).
  • the above-mentioned first information matrix can be expressed as:
  • the frequency offsets between M STAs and APs are ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M , and the training sequences sent by STAs in M STAs will be sent between symbols due to the frequency offset and cross emission.
  • the phase rotation of the training sequence will skip two symbols, so the phase rotation angle of the training sequence sent on a certain symbol Q relative to the training sequence sent on the first symbol is j2 ⁇ f(Q-1)2T.
  • the first information matrix is expressed as:
  • Equations 1-6 After the first information matrix is inverted, the result obtained by multiplying the second information matrix to the left has standard eigenvalue decomposition properties, which can be obtained by using eigenvalue decomposition
  • the eigenvalue can be obtained by solving: The frequency offset values between the M STAs and the AP are calculated based on the above eigenvalues to be ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M, respectively .
  • the eigenvalues can be solved: Based on this characteristic value, the frequency offset values between M STAs and APs are calculated as ⁇ f 1 , ⁇ f 2 ,..., ⁇ f M ; when N first positions and N second positions are arranged crosswise (N is less than Q) In this case, the eigenvalues can be solved: Based on this characteristic value, the frequency offset values between the M STAs and the AP are calculated to be ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M, respectively .
  • the specific solution process is similar to that shown in case three, and will not be repeated here.
  • the maximum angle value of 2 ⁇ f 1 QT is 2 ⁇ f 1 QT ⁇ 2.016Q degrees, which will result in the inability to identify and distinguish each STA even if the phase identification information is increased as shown in case two.
  • the current 8 STA eigenvalue angles can reach up to 16 degrees, which is close to 22.5 degrees.
  • the number of STAs is larger, or when there is a lot of system noise, which leads to errors in the calculation of eigenvalues, it will lead to misjudgment of STA angles, and there is a certain risk.
  • the latest 802.11ax only supports a maximum of 8 STAs, which can guarantee performance to a certain extent.
  • this embodiment proposes a cross-training sequence group discharge method, that is, the discharge method in FIG. 8(b). So that the angle value of the eigenvalue has nothing to do with the number of STAs, because the eigenvalue is always Therefore, the eigenvalue angle 2 ⁇ f 1 T ⁇ 2.016 degrees, which is far less than 360/M degrees, reduces the possibility of misjudgment.
  • the data frames sent by the M STAs received by the AP are shown in Figure 7(b), and in S610, the STAs generate the second set of training sequences based on the P1 matrix.
  • the above-mentioned first information matrix can be expressed as the above-mentioned formula 1-4.
  • this application mainly considers different frequency offsets between STAs and APs.
  • the frequency offsets between M STAs and APs are ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M
  • the training sequences sent by STAs in M STAs will be sent between symbols due to the frequency offset and cross emission.
  • the phase rotation of the training sequence will skip two symbols, so the phase rotation angle of the training sequence sent on a certain symbol Q relative to the training sequence sent on the first symbol is j2 ⁇ f(Q-1)2T.
  • the first information matrix is expressed as the above formula 1-5.
  • the second set of training sequences is obtained by multiplying the preset training sequence by the P1 matrix, so the second information matrix is expressed as:
  • the eigenvalue can be obtained by solving:
  • the frequency offset values between the M STAs and the AP are calculated based on the above eigenvalues to be ⁇ f 1 , ⁇ f 2 , ..., ⁇ f M, respectively .
  • the uplink multi-site channel estimation method provided by this application can calculate a more accurate frequency offset value, and then perform channel estimation based on the calculated frequency offset value Time can improve the accuracy of channel estimation.
  • the P matrix shown above can be corrected based on the frequency offset values to obtain the corrected P matrix.
  • the method process shown in FIG. 6 further includes S640.
  • the AP performs channel estimation based on the modified matrix, including the following three situations:
  • the AP After the AP inverts the corrected P matrix, it multiplies it by the first information matrix to obtain the channel information matrix, and completes the channel estimation.
  • the AP multiplies the corrected P matrix left by the matrix after the above A phase matrix, inversely multiplies it by the second information matrix to obtain the channel information matrix, and completes the channel estimation; or,
  • the AP After the AP inverts the corrected P matrix, it multiplies it by the first information matrix to obtain the first channel information;
  • AP multiplies the corrected P matrix by the above A phase , or The matrix is inverted and multiplied by the second information matrix to obtain the second channel information, the weighted average of the first channel information and the second channel information is calculated to obtain the channel information matrix, and the channel estimation is completed.
  • calculating the weighted average of the first channel information and the second channel information can be understood as calculating the arithmetic average or geometric average of the first channel information and the second channel information, etc.
  • the specific method for calculating the average value of the first channel information and the second channel information in the embodiment of the present application is not limited. It should also be understood that when the average value of the first channel information and the second channel information is used as the channel information matrix to be calculated, the accuracy of 3dB can be improved, for example, the signal-to-noise ratio is increased by 3dB, or the transmission power is increased by 3dB, or the channel estimation is accurate. The degree is increased by 3dB.
  • the following two STAs communicate with the AP as an example for description.
  • the AP includes antenna #1 and antenna #2, STA#1 and STA#2 are single-antenna STAs, and STA#1 And the frequency offset values between STA#2 and AP are ⁇ f 1 and ⁇ f 2 respectively , and the P matrix is
  • the AP estimates the channel information of the two STAs to include the following four situations:
  • the form of the frames respectively sent by STA#1 and STA#2 received by the AP is shown in Figure 8(a).
  • the data received by the antenna #1 of the AP is the sum of two parts of the data of the data experience channel h 11 of the STA #1 and the data experience channel h 12 of the STA #2.
  • the data received by the antenna #2 of the AP is the sum of the data of the data experience channel h 21 of the STA #1 and the data experience channel h 22 of the STA #2.
  • the data sent on the second symbol of STA#1 should be -1, but due to phase rotation, it becomes Similarly, the data sent on the second symbol of STA#2 should be 1, but due to phase rotation, it becomes Then the first information matrix received by the AP is:
  • the second information matrix received by the AP is:
  • AP uses the first information matrix to inverse and multiplies it on the second information matrix, then the corresponding eigenvalue standard form can be obtained:
  • the eigenvalue can be obtained with Find the angle of its characteristic value and divide by the corresponding coefficient to get ⁇ f 1 and ⁇ f 2 .
  • the corrected P matrix P fix can be obtained as Channel estimation based on the P fix includes:
  • Equation 2-1 Invert the P fix and multiply it by the above-mentioned first information matrix (Equation 2-1), then we can get Or, multiply the eigenvalue matrix in Equation 2-2 by this P fix After inverting and multiplying by the above second information matrix (Equation 2-2), you can get or,
  • the P fix is inverted and multiplied by the above first information matrix (Equation 2-1) to get The eigenvalue matrix in the P fix left multiplication formula 2-2
  • Equation 2-2 After inverting and multiplying by the above second information matrix (Equation 2-2), you can get begging with The average of The channel estimation will have the influence of noise, so combining the two channel estimations and averaging can increase the accuracy of 3dB, which can be understood as the transmission power, or the signal-to-noise ratio has increased by 3dB, or the channel estimation accuracy has increased by 3dB .
  • 3dB can be understood as the transmission power, or the signal-to-noise ratio has increased by 3dB, or the channel estimation accuracy has increased by 3dB .
  • noise is not considered with It should be an accurate channel information matrix.
  • the form of the frames respectively sent by STA#1 and STA#2 received by the AP is shown in Figure 8(a), and STA#1 and STA#2 respectively generate the second set of training sequences in their respective training sequences based on the P1 matrix.
  • the P1 matrix is among them, It is called the phase recognition matrix.
  • the first information matrix received by the AP is:
  • the second information matrix received by the AP is:
  • AP uses the first information matrix to inverse and multiplies it on the second information matrix, then the corresponding eigenvalue standard form can be obtained:
  • the eigenvalue can be obtained with Find eigenvalues angle phaseshift 1 + 2 ⁇ f 1 2T and phaseshift 2 + 2 ⁇ f 2 2T, then further coefficients can be obtained by dividing ⁇ f 1 and ⁇ f 2.
  • the corrected P matrix P fix can be obtained from ⁇ f 1 and ⁇ f 2 , and the channel estimation based on the P fix is similar to that shown in case 1, and will not be repeated here.
  • the first information matrix received by the AP is:
  • the second information matrix received by the AP is:
  • AP uses the first information matrix to inverse and multiplies it on the second information matrix, then the corresponding eigenvalue standard form can be obtained:
  • the eigenvalue can be obtained with Find the angle of its characteristic value and divide by the corresponding coefficient to get ⁇ f 1 and ⁇ f 2 .
  • the corrected P matrix P fix can be obtained from ⁇ f 1 and ⁇ f 2 , and the channel estimation based on the P fix is similar to that shown in case 1, and will not be repeated here.
  • the first information matrix received by the AP is:
  • the second information matrix received by the AP is:
  • the eigenvalue can be obtained with Find eigenvalues angle phaseshift 1 + 2 ⁇ f 1 T and phaseshift 2 + 2 ⁇ f 2 T, then further coefficients can be obtained by dividing ⁇ f 1 and ⁇ f 2.
  • the corrected P matrix P fix can be obtained from ⁇ f 1 and ⁇ f 2 , and the channel estimation based on the P fix is similar to that shown in case 1, and will not be repeated here.
  • the frame sent by the STA includes two sets of training sequences.
  • the frame sent by the STA is not limited to include only two sets of training sequences.
  • four sets of training sequences may also be included.
  • the process of calculating the frequency offset value the four sets of training sequences are divided into two.
  • the frequency offset values are calculated based on the two sets of training sequences, and then the average value of the two sets of frequency offset values is calculated, and the average value is used as the calculated frequency offset value. The specific process will not be repeated here.
  • the method for uplink multi-site channel estimation provided in the embodiment of the present application can more accurately estimate the channel information matrix.
  • the channel information matrix can be used in the following two situations:
  • the STA uplink MU-MIMO sends the data load, and the AP side uses the channel information matrix to invert and multiply the data matrix, then the data can be accurately orthogonally balanced and the data of each STA can be distinguished.
  • the AP side distinguishes the data of each STA as:
  • the AP uses this channel to pre-code the downlink MU-MIMO data, that is, the channel is inverted and multiplied by the transmitted data, which is equivalent to pre-equalization on the AP side. So that the data received by multiple STAs does not crosstalk with each other.
  • the data sent by the AP can be expressed as:
  • the data received on the STA side is:
  • the size of the sequence numbers of the foregoing processes does not mean the order of execution.
  • the execution order of the processes should be determined by their functions and internal logic, and should not correspond to the implementation process of the embodiments of this application. Constitute any limitation.
  • FIG. 9 is a schematic diagram of the apparatus 90 for uplink multi-site channel estimation proposed in this application.
  • the device 90 includes a processing unit 910 and a sending unit 920.
  • the processing unit 910 is configured to generate a frame.
  • the frame includes a first set of training sequences and a second set of training sequences.
  • the first set of training sequences and the second set of training sequences are used to calculate the frequency offset value between the STA and the access point AP, Frequency offset value is used for channel estimation;
  • the sending unit 920 is configured to send frames to the AP.
  • the device 90 completely corresponds to the STA in the method embodiment, and the device 90 may be the STA in the method embodiment, or a chip or functional module inside the STA in the method embodiment.
  • the corresponding units of the device 90 are used to execute the corresponding steps executed by the STA in the method embodiment shown in FIG. 6.
  • the processing unit 910 in the device 90 executes the steps implemented or processed internally by the STA in the method embodiment. For example, step S610 of generating a frame in FIG. 6 is performed.
  • the sending unit 920 executes the steps sent by the STA in the method embodiment. For example, perform step S620 of sending a frame to the AP in FIG. 6;
  • the device 90 may also include a receiving unit, which is used to perform the step of receiving by the STA, for example, receiving information sent by other devices.
  • the sending unit 920 and the receiving unit may constitute a transceiver unit, and have the functions of receiving and sending at the same time.
  • the processing unit 910 may be a processor.
  • the sending unit 920 may be a transmitter, and the receiving unit may be a receiver. The receiver and transmitter can be integrated to form a transceiver.
  • FIG. 10 is a schematic structural diagram of a STA 1000 applicable to an embodiment of the present application.
  • the STA1000 can be applied to the system shown in Figure 1.
  • FIG. 10 only shows the main components of the STA.
  • the STA 1000 includes a processor (corresponding to the processing unit 910 shown in FIG. 9), a memory, a control circuit, an antenna, and an input and output device (corresponding to the sending unit 920 shown in FIG. 9).
  • the processor is used to control the antenna and the input and output devices to send and receive signals
  • the memory is used to store a computer program
  • the processor is used to call and run the computer program from the memory to execute the method for uplink multi-site channel estimation proposed in this application by the STA. Corresponding process and/or operation. I won't repeat them here.
  • FIG. 10 only shows a memory and a processor. In an actual STA, there may be multiple processors and memories.
  • the memory may also be referred to as a storage medium or a storage device, etc., which is not limited in the embodiment of the present application.
  • FIG. 11 is a schematic diagram of the apparatus 1100 for uplink multi-site channel estimation proposed in this application.
  • the device 1100 includes a receiving unit 1110 and a processing unit 1120.
  • the receiving unit 1110 is configured to receive frames respectively sent by multiple STAs.
  • the frames include a first set of training sequences and a second set of training sequences.
  • the first set of training sequences and the second set of training sequences are used to solve the STA and Frequency offset value between access points AP;
  • the processing unit 1120 is configured to perform channel estimation based on the frequency offset values between the multiple STAs and the AP, respectively.
  • the device 1100 completely corresponds to the AP in the method embodiment, and the device 1100 may be the AP in the method embodiment, or a chip or functional module inside the AP in the method embodiment.
  • the corresponding unit of the device 1100 is used to execute the corresponding steps executed by the AP in the method embodiment shown in FIG. 6.
  • the receiving unit 1110 in the device 1100 executes the steps sent by the AP in the method embodiment. For example, step S620 of receiving a frame sent by an STA in FIG. 6 is performed.
  • the processing unit 1120 in the device 1100 executes the steps implemented or processed inside the AP in the method embodiment. For example, step S630 of calculating the frequency offset value in FIG. 6 is performed, and step S640 of performing channel estimation in FIG. 6 is performed.
  • the apparatus 1100 may further include a sending unit, which is configured to perform the steps of AP sending and send information to other devices, for example, perform step S611 of sending instruction information to the STA in FIG. 6.
  • the receiving unit 1110 and the sending unit may constitute a transceiver unit, and have the functions of receiving and sending at the same time.
  • the processing unit 1120 may be a processor.
  • the sending unit may be a transmitter.
  • the receiving unit 1110 may be a receiver. The receiver and transmitter can be integrated to form a transceiver.
  • FIG. 12 is a schematic structural diagram of an AP 1200 applicable to an embodiment of the present application, which can be used to implement the function of the AP in the above method for uplink multi-site channel estimation. It can be a schematic diagram of the AP structure.
  • the AP includes 1210 part and 1220 part.
  • the 1210 part is mainly used for the transmission and reception of radio frequency signals and the conversion between radio frequency signals and baseband signals; the 1220 part is mainly used for baseband processing and control of positioning management components.
  • the 1210 part can generally be called a transceiver unit, transceiver, transceiver circuit, or transceiver.
  • the part 1220 is usually the control center of the positioning management component, and may generally be referred to as a processing unit, which is used to control the positioning management component to perform processing operations on the AP side in the foregoing method embodiment.
  • the transceiver unit of part 1210 may also be called a transceiver or a transceiver, etc., which includes an antenna and a radio frequency unit, and the radio frequency unit is mainly used for radio frequency processing.
  • the device for implementing the receiving function in part 1210 can be regarded as the receiving unit, and the device for implementing the sending function as the sending unit, that is, the part 810 includes the receiving unit and the sending unit.
  • the receiving unit may also be called a receiver, a receiver, or a receiving circuit, etc.
  • the sending unit may be called a transmitter, a transmitter, or a transmitting circuit, etc.
  • the 1220 part may include one or more single boards, and each single board may include one or more processors and one or more memories.
  • the processor is used to read and execute the program in the memory to realize the baseband processing function and control the positioning management component. If there are multiple boards, each board can be interconnected to enhance processing capabilities. As an optional implementation, multiple single boards may share one or more processors, or multiple single boards may share one or more memories, or multiple single boards may share one or more processing at the same time. Device.
  • FIG. 12 is only an example and not a limitation, and the above-mentioned AP including a transceiver unit and a processing unit may not rely on the structure shown in FIG. 12.
  • the AP 1200 shown in FIG. 12 can implement the AP function involved in the method embodiment in FIG. 6.
  • the operations and/or functions of each unit in the AP 1200 are respectively for implementing the corresponding process executed by the AP in the method embodiment of the present application. To avoid repetition, detailed description is omitted here.
  • the structure of the AP illustrated in FIG. 12 is only a possible form, and should not constitute any limitation to the embodiment of the present application. This application does not exclude the possibility of other AP structures that may appear in the future.
  • the embodiment of the present application also provides a communication system, which includes the aforementioned STA and AP.
  • This application also provides a computer-readable storage medium that stores instructions in the computer-readable storage medium.
  • the computer executes the steps performed by the STA in the method shown in FIG. 6 .
  • the present application also provides a computer-readable storage medium that stores instructions in the computer-readable storage medium.
  • the computer executes the steps performed by the AP in the method shown in FIG. 6 .
  • the present application also provides a computer program product containing instructions.
  • the computer program product runs on a computer, the computer executes the steps performed by the STA in the method shown in FIG. 6.
  • This application also provides a computer program product containing instructions.
  • the computer program product runs on a computer, the computer executes each step executed by the AP in the method shown in FIG. 6.
  • the application also provides a chip including a processor.
  • the processor is used to read and run a computer program stored in the memory to execute the corresponding operation and/or process performed by the STA in the method for uplink multi-site channel estimation provided in this application.
  • the chip further includes a memory, the memory and the processor are connected to the memory through a circuit or a wire, and the processor is used to read and execute the computer program in the memory.
  • the chip further includes a communication interface, and the processor is connected to the communication interface.
  • the communication interface is used to receive data and/or information that needs to be processed, and the processor obtains the data and/or information from the communication interface, and processes the data and/or information.
  • the communication interface may be an input/output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip.
  • the processor may also be embodied as a processing circuit or a logic circuit.
  • the application also provides a chip including a processor.
  • the processor is used to read and run a computer program stored in the memory to execute the corresponding operation and/or process performed by the AP in the method for uplink multi-site channel estimation provided in this application.
  • the chip further includes a memory, the memory and the processor are connected to the memory through a circuit or a wire, and the processor is used to read and execute the computer program in the memory.
  • the chip further includes a communication interface, and the processor is connected to the communication interface.
  • the communication interface is used to receive data and/or information that needs to be processed, and the processor obtains the data and/or information from the communication interface, and processes the data and/or information.
  • the communication interface may be an input/output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip.
  • the processor may also be embodied as a processing circuit or a logic circuit.
  • the disclosed system, device, and method may be implemented in other ways.
  • the device embodiments described above are merely illustrative, for example, the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components may be combined or It can be integrated into another system, or some features can be ignored or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.
  • the functional units in the various embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium.
  • the technical solution of the present application essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the various embodiments of the present application.
  • the aforementioned storage media include: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other media that can store program code .
  • the term "and/or” in this application is only an association relationship that describes associated objects, which means that there can be three types of relationships, for example, A and/or B, which can mean that A alone exists, and both A and B exist. , There are three cases of B alone.
  • the character "/" in this document generally means that the associated objects before and after are in an "or” relationship; the term “at least one” in this application can mean “one” and "two or more", for example, A At least one of, B and C can mean: A alone exists, B alone exists, C exists alone, A and B exist alone, A and C exist simultaneously, C and B exist simultaneously, and A and B and C exist simultaneously, this Seven situations.
  • multiply left/multiply right in this application describes the calculation method between matrices.
  • matrix A is multiplied by matrix B to the left to obtain matrix BA
  • matrix A is multiplied by matrix B to the right to obtain matrix AB
  • multiply left by/multiply by right describes the calculation method between matrices.
  • matrix A is multiplied by matrix B on the left to obtain matrix AB
  • matrix A is multiplied by matrix B on the right to obtain matrix BA.

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Abstract

本申请提供了一种上行多站点信道估计的方法、站点和接入点。能够应用在上行多站点多输入多输出的场景下，该上行多站点信道估计的方法包括：STA生成包括第一组训练序列和第二组训练序列的帧，并将该帧发送给AP，AP基于接收到的第一组训练序列和第二组训练序列求解STA与AP之间的频偏值，并且基于计算得到的频偏值进行信道估计。本申请提供的技术方案可以使得AP更准确获知多个STA分别与AP之间的频偏值，从而提高信道估计的精度。

Description

上行多站点信道估计的方法、站点和接入点
本申请要求于2019年09月12日提交中国专利局、申请号为201910866513.3、申请名称为“上行多站点信道估计的方法、站点和接入点”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信领域，并且更具体地，涉及一种上行多站点信道估计的方法、站点和接入点。
背景技术
随着无线局域网技术的发展，引入上行多站点多输入多输出(uplink mulit-user multiple input multiple output，UL MU-MIMO)技术，上行多个站点(station，STA)向接入点(access point，AP)同时发送数据，通过空间复用的技术以及AP侧的正交均衡，消除各个站点之间的干扰，有效增加了上行的频谱资源利用率。
然而站点各型各样，站点的射频链路各不相同，所以站点在发送数据时所用的载波频率很难一致，即多个站点无法做到频率同步。这就导致AP侧进行信道估计时，多个站点的信道之间难以正交、互相串扰，大大降低信道估计精度。因此，如何提高上行多站点信道多输入多输出场景下，多个站点的信道信息的估计精度，成为亟待解决的问题。
发明内容
本申请提供一种上行多站点信道估计的方法、站点和接入点，通过多个站点分别向接入点发送包括两组训练序列的帧，该两组训练序列能够提高求解站点与接入点之间的频偏值的准确度，从而能够提高接入点基于该频偏值进行信道估计时的精度。
第一方面，提供了一种上行多站点信道估计的方法，应用于与接入点AP通信的多个站点STA中的任意一个STA，包括：该站点STA生成帧，该帧中包括包括第一组训练序列和第二组训练序列，该第一组训练序列和第二组训练序列用于求解该STA与接入点AP之间频偏值，该频偏值用于信道估计；该STA向该AP发送该帧。
本申请实施例提供的上行多站点信道估计的方法，STA生成包括第一组训练序列和第二组训练序列的帧，并向AP发送生成的帧。具体地，该两组训练序列能够提高求解STA与AP之间的频偏值的准确度，从而能够提高AP基于该频偏值进行信道估计时的精度。
结合第一方面，在第一方面的某些实现方式中，在该STA生成帧之前，该方法还包括：该STA接收来自该AP的指示信息，该指示信息用于指示该STA生成该帧。
本申请实施例提供的上行多站点信道估计的方法，AP可以向STA发送指示信息，指示STA生成包括上述第一组训练序列和第二组训练序列的帧。
结合第一方面，在第一方面的某些实现方式中，该指示信息还用于指示该STA生成 该帧的过程是否使用预设相位识别矩阵，和/或，该指示信息还用于指示该第一组训练序列和该第二组训练序列在该帧中的排列方式。
本申请实施例提供的上行多站点信道估计的方法，上述的指示信息还可以用于指示STA生成帧时是否增加相位标识，和/或，指示STA将上述的第一组训练序列和该第二组训练序列排放在帧中的排列方式，为STA生成的帧的结构提供可选的方式。
结合第一方面，在第一方面的某些实现方式中，该第一组训练序列由预设训练序列乘以P矩阵中对应于该STA的元素得到，该第二组训练序列由预设训练序列乘以该P矩阵或P1矩阵中对应于该STA的元素得到，其中，该P1矩阵为基于预设相位识别矩阵确定的矩阵，该P矩阵为该AP和该多个STA已知的用于信道估计的矩阵。
本申请实施例提供的上行多站点信道估计的方法，可以基于P矩阵或P1矩阵确定上述的第一组训练序列和第二组训练序列为得到第一组训练序列和第二组训练序列提供可行的方案。
结合第一方面，在第一方面的某些实现方式中，该第一组训练序列占用该帧中的Q个第一位置，该第二组训练序列占用该帧中的Q个第二位置，其中，该Q个第一位置和该Q个第二位置依次先后排列；或者，该Q个第一位置和Q个第二位置等间隔交叉排列，该Q为与M满足预设的对应关系的整数，M为上述多个STA的天线总数。
本申请实施例提供的上行多站点信道估计的方法，上述的第一组训练序列和第二组训练序列在帧中的位置有多种可能，为第一组训练序列和第二组训练序列的排列方式提供灵活的方案。
结合第一方面，在第一方面的某些实现方式中，上述的第一组训练序列中包括一个或多个第一训练序列，上述的第二组训练序列中包括一个或多个第二训练序列。
本申请实施例提供的上行多站点信道估计的方法，上述的第一组训练序列和第二组训练序列中可以分别包括至少一个训练序列。
第二方面，提供了一种上行多站点信道估计的方法，包括：接入点AP接收多个STA分别发送的帧，该帧中包括第一组训练序列和第二组训练序列，该第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值；该AP基于该M个STA分别与该AP之间的频偏值，进行信道估计。
本申请实施例提供的上行多站点信道估计的方法，AP从多个STA接收到包括第一组训练序列和第二组训练序列的帧。具体地，该两组训练序列能够提高求解STA与AP之间的频偏值的准确度，从而能够提高AP基于该频偏值进行信道估计时的精度。
结合第二方面，在第二方面的某些实现方式中，该AP向该STA发送指示信息，该指示信息用于指示该STA生成该帧。
本申请实施例提供的上行多站点信道估计的方法，AP可以向STA发送指示信息，指示STA生成包括上述第一组训练序列和第二组训练序列的帧。
结合第二方面，在第二方面的某些实现方式中，该指示信息还用于指示该STA生成该帧的过程是否使用预设相位识别矩阵，和/或，该指示信息还用于指示该第一组训练序列和该第二组训练序列在该帧中的排列方式。
本申请实施例提供的上行多站点信道估计的方法，上述的指示信息还可以用于指示STA生成帧时是否增加相位标识，和/或，指示STA将上述的第一组训练序列和该第二组 训练序列排放在帧中的排列方式，为STA生成的帧的结构提供可选的方式。
结合第二方面，在第二方面的某些实现方式中，该第一组训练序列由预设训练序列乘以P矩阵中对应于该STA的元素得到，该第二组训练序列由预设训练序列乘以P矩阵或P1矩阵中对应于该STA的元素得到，其中，该P1矩阵为基于预设相位识别矩阵确定的矩阵，该P矩阵为该AP和该多个STA已知的用于信道估计的矩阵。
本申请实施例提供的上行多站点信道估计的方法，可以基于P矩阵或P1矩阵确定上述的第一组训练序列和第二组训练序列，为得到第一组训练序列和第二组训练序列提供可行的方案。
结合第二方面，在第二方面的某些实现方式中，该第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值包括：该多个STA分别发送的多个第一组训练序列和信道信息矩阵用于确定第一信息矩阵；该多个STA分别发送的多个第二组训练序列和信道信息矩阵用于确定第二信息矩阵；第一信息矩阵和该第二信息矩阵用于求解该多个STA分别与该AP之间的频偏值。
本申请实施例提供的上行多站点信道估计的方法，每个STA分别发送的训练序列中包括的第一组训练序列和第二组训练序列在经过各个STA和AP之间的信道分别发送到AP侧之后，AP能够接收到第一信息矩阵和第二信息矩阵，并且基于第一信息矩阵和该第二信息矩阵求解该M个STA分别与该AP之间的频偏值，为AP确定频偏值提供可行的方案。
结合第二方面，在第二方面的某些实现方式中，该AP基于该多个STA分别与该AP之间的频偏值，进行信道估计包括：该AP基于该多个STA分别与该AP之间的频偏值修正该P矩阵，得到修正后的P矩阵；该AP基于该第一信息矩阵和/或该第二信息矩阵，以及该修正后的P矩阵确定该信道信息矩阵。
本申请实施例提供的上行多站点信道估计的方法，AP获得多个STA分别与该AP之间的频偏值之后，基于频偏值和P矩阵得到修正后的P矩阵，并根据修正后的P矩阵以及上述的第一信息矩阵和/或该第二信息矩阵确定出信道信息矩阵，完成信道估计。
结合第二方面，在第二方面的某些实现方式中，该第一组训练序列占用该帧中的Q个第一位置，该第二组训练序列占用该帧中的Q个第二位置，其中，该Q个第一位置和该Q个第二位置依次先后排列；或者，该Q个第一位置和Q个第二位置等间隔交叉排列，该Q为与M满足预设的对应关系的整数，M为上述多个STA的天线总数。
本申请实施例提供的上行多站点信道估计的方法，上述的第一组训练序列和第二组训练序列在帧中的位置由多种可能，为第一组训练序列和第二组训练序列的排列方式提供灵活的方案。
结合第二方面，在第二方面的某些实现方式中，上述的第一组训练序列中包括一个或多个第一训练序列，上述的第二组训练序列中包括一个或多个第二训练序列。
本申请实施例提供的上行多站点信道估计的方法，上述的第一组训练序列和第二组训练序列中可以分别包括至少一个训练序列。
第三方面，提供了一种上行多站点信道估计的方法，应用于与接入点AP通信的多个站点STA中的任意一个STA，包括：该STA生成帧，该帧中包括第一组训练序列和第二组训练序列，该第一组训练序列中包括Q个第一训练序列，该第二组训练序列中包括Q 个第二训练序列；该STA向该AP发送该帧，其中，Q为与M满足预设的对应关系的整数，M为多个STA的天线总数。
结合第三方面，在第三方面的某些实现方式中，Q个第一训练序列分别与Q个第二训练序列相同。
结合第三方面，在第三方面的某些实现方式中，Q个第二训练序列分别为Q个第一训练序列增加相位识别信息之后的训练序列。
结合第三方面，在第三方面的某些实现方式中，Q个第一训练序列和Q个第二训练序列在上述帧中依次先后排列；或者，Q个第一训练序列和Q个第二训练序列在上述帧中等间隔交叉排列。
第四方面，提供了一种上行多站点信道估计的方法，应用于与多个站点STA通信的接入点AP，包括：该AP接收来自该STA的帧，该帧中包括第一组训练序列和第二组训练序列，该第一组训练序列中包括Q个第一训练序列，该第二组训练序列中包括Q个第二训练序列；该AP基于该第一组训练序列和第二组训练序列进行信道估计，其中，Q为与M满足预设的对应关系的整数，M为多个STA的天线总数。
结合第四方面，在第四方面的某些实现方式中，Q个第一训练序列分别与Q个第二训练序列相同。
结合第四方面，在第四方面的某些实现方式中，Q个第二训练序列分别为Q个第一训练序列增加相位识别信息之后的训练序列。
结合第四方面，在第四方面的某些实现方式中，Q个第一训练序列和Q个第二训练序列在上述帧中依次先后排列；或者，Q个第一训练序列和Q个第二训练序列在上述帧中等间隔交叉排列。
第五方面，提供一种上行多站点信道估计的装置，所述上行多站点信道估计的装置包括处理器，用于实现上述第一方面和第三方面描述的方法中STA的功能。
可选地，所述上行多站点信道估计的装置还可以包括存储器，所述存储器与所述处理器耦合，所述处理器用于实现上述第一方面和第三方面描述的方法中STA的功能。在一种可能的实现中，所述存储器用于存储程序指令和数据。所述存储器与所述处理器耦合，所述处理器可以调用并执行所述存储器中存储的程序指令，用于实现上述第一方面和第三方面描述的方法中STA的功能。
可选地，所述上行多站点信道估计的装置还可以包括通信接口，所述通信接口用于所述上行多站点信道估计的装置与其它设备进行通信。当该上行多站点信道估计的装置为终端设备时，所述通信接口可以为收发器、输入/输出接口、或电路等。
在一种可能的设计中，所述上行多站点信道估计的装置包括：处理器和通信接口，
所述处理器用于运行计算机程序，以使得所述上行多站点信道估计的装置实现上述第一方面和第三方面描述的任一种方法；
所述处理器利用所述通信接口与外部通信。
可以理解，所述外部可以是处理器以外的对象，或者是所述装置以外的对象。
在另一种可能的设计中，该上行多站点信道估计的装置为芯片或芯片系统。所述通信接口可以是该芯片或芯片系统上输入/输出接口、接口电路、输出电路、输入电路、管脚或相关电路等。所述处理器也可以体现为处理电路或逻辑电路。
第六方面，提供一种上行多站点信道估计的装置，所述上行多站点信道估计的装置包括处理器，用于实现上述第二方面和第四方面描述的方法中AP的功能。
可选地，所述上行多站点信道估计的装置还可以包括存储器，所述存储器与所述处理器耦合，所述处理器用于实现上述第二方面和第四方面描述的方法中AP的功能。在一种可能的实现中，所述存储器用于存储程序指令和数据。所述存储器与所述处理器耦合，所述处理器可以调用并执行所述存储器中存储的程序指令，用于实现上述第二方面和第四方面描述的方法中AP的功能。
可选地，所述上行多站点信道估计的装置还可以包括通信接口，所述通信接口用于所述上行多站点信道估计的装置与其它设备进行通信。当该上行多站点信道估计的装置为网络设备时，所述通信接口可以为收发器、输入/输出接口、或电路等。
在一种可能的设计中，所述上行多站点信道估计的装置包括：处理器和通信接口，
所述处理器利用所述通信接口与外部通信；
所述处理器用于运行计算机程序，以使得所述上行多站点信道估计的装置实现上述第二方面和第四方面描述的任一种方法。
可以理解，所述外部可以是处理器以外的对象，或者是所述装置以外的对象。
在另一种可能的设计中，该上行多站点信道估计的装置为芯片或芯片系统。所述通信接口可以是该芯片或芯片系统上的输入/输出接口、接口电路、输出电路、输入电路、管脚或相关电路等。所述处理器也可以体现为处理电路或逻辑电路。
第七方面，本申请提供一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行上述各方面所述的方法。
第八方面，本申请提供一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述各方面所述的方法。
第九方面，提供了一种通信系统，包括第五方面所示的上行多站点信道估计的装置和第六方面所示的上行多站点信道估计的装置。
附图说明
图1是一个典型的WLAN部署场景的系统示意图。
图2中(a)和(b)是本申请实施例提供的一种AP和STA之间通过MU-MIMO方式上行传输的示意图。
图3是本申请实施例提供的一种两个STA向AP发送数据的示意图。
图4是本申请实施例提供的一种单天线STA发送数据的示意图。
图5是本申请实施例提供的一种多STA分别对应的正交序列的示意图。
图6是本申请实施例提供的一种上行多站点信道估计的方法的示意性流程图。
图7中(a)-(c)是本申请实施例提供的帧的示意图。
图8中(a)和(b)是本申请实施例提供的两个STA生成的帧的示意图。
图9是本申请提出的上行多站点信道估计的装置90的示意图。
图10是适用于本申请实施例的STA 1000的结构示意图。
图11是本申请提出的上行多站点信道估计的装置1100的示意图。
图12是适用于本申请实施例的AP 1200的结构示意图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
本申请实施例可以应用于无线局域网(wireless local area network，WLAN)，WLAN中可以包括多个基本服务集(basic service set，BSS)。BSS的网络节点包括AP和STA。每个BSS可以包含一个AP和多个关联于该AP的STA。
上述的AP也可以称之为无线访问接入点或热点等。AP是用户终端进入有线网络的接入点，主要部署于家庭、大楼内部以及园区内部。典型的AP覆盖半径为几十米至上百米。应理解，AP也可以部署于户外。AP相当于一个连接有线网和无线网的桥梁，其主要作用是将各个无线网络的客户端连接到一起，然后将无线网络接入以太网。目前AP主要采用的标准为电气和电子工程师协会(institute of electrical and electronics engineers，IEEE)802.11系列。具体地，AP可以是带有无线保真(wireless fidelity，WiFi)芯片的终端设备或者网络设备。可选地，AP可以为支持WLAN制式的设备。
STA在本申请中表示用户终端，所以下文中可以直接称之为用户终端或用户。STA可以是无线通讯芯片、无线传感器或无线通信终端。例如，支持WiFi通讯功能的移动电话、支持WiFi通讯功能的平板电脑、支持WiFi通讯功能的机顶盒、支持WiFi通讯功能的智能电视、支持WiFi通讯功能的智能可穿戴设备和支持WiFi通讯功能的计算机。可选地，STA可以为支持WLAN制式的设备。
图1是一个典型的WLAN部署场景的系统示意图，包括一个AP和4个STA，AP分别与STA#1、STA#2、STA#3和STA#4进行通信。AP和STA之间的上行传输方式包括但不限于正交频分多址(orthogonal frequency-division multiple access，OFDMA)方式，多站点信道多输入多输出(mulit-user multiple input multiple output，MU-MIMO)方式或者OFDMA与MU-MIMO混合传输方式。
本申请中AP和多个STA之间的上行传输方式为MU-MIMO方式，要求AP天线个数N要大于等于与之关联的所有STA的天线的总和M。应理解，任意一个STA可以包括多个天线，当某一STA有两根天线，可以将该STA等效成两个相同的单天线STA，只是两个STA到AP的信道不同而已。如图2所示，图2是本申请实施例提供的一种AP和STA之间通过MU-MIMO方式上行传输的示意图。图2中AP包括N个天线(如图2所示的天线#1～天线#N)，所有STA的天线根数的总和为M。图2中h NM表示STA侧的天线M与AP侧的天线N之间的信道。
图2(a)表示一个STA可以包括多个天线，如果该STA与AP之间存在频率差异，则该多个天线发出的信号与AP之间存在的频率差异相同。图2(b)是图2(a)的等效变换，即包括多个天线的STA，可以等效为多个相同的单天线STA，应理解这种等效变换只是为了更容易理解本申请提供的技术方案，对本申请的保护范围不构成任何限定。
此外，为了便于理解本申请实施例，做出以下几点说明。
第一，在本申请中，“用于指示”可以包括用于直接指示和用于间接指示。当描述某一指示信息用于指示A时，可以包括该指示信息直接指示A或间接指示A，而并不代表该指示信息中一定携带有A。
将指示信息所指示的信息称为待指示信息，则具体实现过程中，对待指示信息进行指 示的方式有很多种，例如但不限于，可以直接指示待指示信息，如待指示信息本身或者该待指示信息的索引等。也可以通过指示其他信息来间接指示待指示信息，其中该其他信息与待指示信息之间存在关联关系。还可以仅仅指示待指示信息的一部分，而待指示信息的其他部分则是已知的或者提前约定的。例如，还可以借助预先约定(例如协议规定)的各个信息的排列顺序来实现对特定信息的指示，从而在一定程度上降低指示开销。同时，还可以识别各个信息的通用部分并统一指示，以降低单独指示同样的信息而带来的指示开销。
第二，在本申请中示出的第一、第二以及各种数字编号(例如，“#1”、“#2”等)仅为描述方便，用于区分的对象，并不用来限制本申请实施例的范围。例如，区分第一组训练序列和第二组训练序列等。而不是用于描述特定的顺序或先后次序。应该理解这样描述的对象在适当情况下可以互换，以便能够描述本申请的实施例以外的方案。
第三，在本申请中，“预设的”可包括预先定义，例如，协议定义。其中，“预先定义”可以通过在设备(例如，包括STA和AP)中预先保存相应的代码、表格或其他可用于指示相关信息的方式来实现，本申请对于其具体的实现方式不做限定。
第四，本申请实施例中涉及的“保存”，可以是指的保存在一个或者多个存储器中。所述一个或者多个存储器，可以是单独的设置，也可以是集成在编码器或者译码器，处理器、或通信装置中。所述一个或者多个存储器，也可以是一部分单独设置，一部分集成在译码器、处理器、或通信装置中。存储器的类型可以是任意形式的存储介质，本申请并不对此限定。
第五，本申请实施例中涉及的“协议”可以是指通信领域的标准协议，例如可以包括WiFi协议、新空口(new radio，NR)协议以及应用于未来的通信系统中的相关协议，本申请对此不做限定。
第六，为方便理解，下面对本申请中涉及到的主要参数做简单说明：
h ij：STA#j的天线与AP侧天线#i之间的信道，i，j为正整数。(本申请以单天线的STA为例进行说明的)
Figure PCTCN2020104898-appb-000001
AP侧天线#k接收到第l个符号上的数据大小，k，l为正整数；
Figure PCTCN2020104898-appb-000002
AP侧天线#i在第j个符号的子载波k上收到的信息(本申请以一个子载波为例进行说明的)。
Δf q：STA#q相对AP的频偏。
Figure PCTCN2020104898-appb-000003
STA#q对应的训练序列集合中第W个训练序列相对于第一个训练序列发生相位的旋转大小。
P fix：基于STA与AP之间的频偏值修正的P矩阵。
Figure PCTCN2020104898-appb-000004
STA#h在第i个符号上发送的数据大小。
具体地，上行多站点MIMO主要依赖于AP侧的多天线正交均衡，即AP侧利用训练序列得到空口的链路信息(例如，无线信道状态信息(channel state information，CSI))，进而均衡多站点的有效负载，将多个站点的叠加信息拆分出来，使得各个站点相互正交，互不影响。因此能否准确得到无线信道状态信息，一方面会直接影响上行多站点正交，或者说是影响各个站点获取各自流准确性的关键；另一方面，还可能影响下行数据传输时接入点进行预编码的准确性。
然而用户终端各型各样，站点的射频链路各不相同，所以用户终端在发送信号时所用的载波频率很难一致，即多个站点无法做到频率同步。其中，获得无线信道状态信息的过 程也可以称为信道估计。
首先，结合图3简单说明多个用户终端发送的信号频率不同步对AP侧估计信道带来的影响。图3是本申请实施例提供的一种两个STA向AP发送数据的示意图。图3中包括两个STA(如图3所示的STA#1和STA#2)以及一个AP，其中，STA#1和STA#2可以通过AP接入网络。例如，STA#1和STA#2可以为两个支持WiFi通讯功能的手机，AP可以为带有WiFi芯片的路由器，AP部署有两个天线(如图3所示的天线#1和天线#2)。
一种可能的实现方式，STA#1和STA#2与AP之间没有频率差异，即没有载波频率偏移(carrier frequency offsets，CFO)，则STA#1和STA#2发送的两个正交符号不会有相位的旋转，下文中将CFO简称为频偏值。
例如，STA#1发送的数据为
Figure PCTCN2020104898-appb-000005
然后通过空间信道h 11、h 21，分别达到AP侧的天线#1和天线#2；STA#2发送的数据为
Figure PCTCN2020104898-appb-000006
然后通过空间信道h 12、h 22，分别达到AP侧的天线#1和天线#2。AP侧天线#1和天线#2收到的数据是两个STA经过空口信道后的叠加信号，具体地，天线#1接收到的数据包括
Figure PCTCN2020104898-appb-000007
和
Figure PCTCN2020104898-appb-000008
其中，
Figure PCTCN2020104898-appb-000009
天线#2接收到的数据包括
Figure PCTCN2020104898-appb-000010
和
Figure PCTCN2020104898-appb-000011
其中，
Figure PCTCN2020104898-appb-000012
具体地，本申请实施例中涉及的STA发送的数据可以理解为STA在某个子载波上发送的长训练域(long training field，LTF)，本申请中数据也可以理解为信号。
AP侧只需要对收到数据做简单的数学运算就可以将h 11、h 21、h 12以及h 22求解得到，即得到了CSI。以上过程可以用矩阵方式表示更有利于理解，在AP收到的数据表示为如下公式：
Figure PCTCN2020104898-appb-000013
AP侧已知发送的训练序列组，X 1＝[1 -1]和X 2＝[1 1]，即上式中的矩阵
Figure PCTCN2020104898-appb-000014
该矩阵在目前协议中，称为P矩阵。因此AP侧只需对收到的数据做如下操作即可得到信道矩阵：
Figure PCTCN2020104898-appb-000015
另一种可能的实现方式，STA#1和STA#2分别与AP之间有各自的频偏，例如，STA#1相对AP的频偏为Δf 1，STA#2相对AP的频偏为Δf 2。STA1和STA2在连续的两个正交符号发送数据时，数据会发生相位的旋转，假设每个符号的周期为T，即STA#1在第二个符号上发送的数据相对于STA#1在第一个符号上发送的数据相位旋转了
Figure PCTCN2020104898-appb-000016
同理STA#2在第二个符号上发送的数据相对于STA#2在第一个符号上发送的数据相位旋转了
Figure PCTCN2020104898-appb-000017
则STA#1发送的数据为
Figure PCTCN2020104898-appb-000018
STA#2发送的数据为
Figure PCTCN2020104898-appb-000019
在AP收到的数据表示为如下公式：
Figure PCTCN2020104898-appb-000020
对于AP侧，还是默认两个STA发送的数据对应P矩阵
Figure PCTCN2020104898-appb-000021
因为AP侧并不知道STA有频偏，所以AP按照原有操作，得到：
Figure PCTCN2020104898-appb-000022
可以发现，两个STA中的一个STA的信道都掺杂着另外一个STA的信道，发生了相互串扰。由上述的计算过程可知，是由于P矩阵的非正交导致的，也就是说如果可以在AP侧获知STA的频偏信息，补偿或修正AP侧的P矩阵，使得P矩阵不是上述的
Figure PCTCN2020104898-appb-000023
而是考虑到频偏信息之后的P fix矩阵
Figure PCTCN2020104898-appb-000024
然后再基于矩阵P fix进行求逆解信道，则可以得到准确的信道信息。
上面结合图3详细说明了，当STA与AP之间存在频偏的情况下，AP基于原有的P矩阵无法准确得到STA与AP之间的信道信息，为了得到准确的信道信息首先需要得到P fix矩阵，而获得P fix矩阵的重点在于获知STA与AP之间的频偏值，基于频偏值修正或补偿P矩阵即可得到P fix矩阵。
可选地，让同一个STA在两个符号上发送两个不变的数据，这样在AP侧接收该两个数据时，只需要对比两个符号中，该两个数据的变化即可得到STA与AP的频偏值。
例如，如图4所示，图4是本申请实施例提供的一种单天线STA发送数据的示意图。STA#1本应发出的数据为X 1＝[1 1]，由于STA与AP的频偏值为Δf 1，相当于发送出来的数据为
Figure PCTCN2020104898-appb-000025
则AP天线#1收到的连续两个符号中的数据为
Figure PCTCN2020104898-appb-000026
将收到的两个符号上的数据进行点除求角度，或者共轭求角度，就可以得到两个数据相对旋转的角度2πΔf 1T，进而计算得到Δf 1。
但是，由于在上行多STA发送数据时，AP侧收到的数据是多个STA发送的数据的叠加，信息无法区分，即使发送了重复的数据，由于两个符号上的数据都是多STA数据的叠加，所以各STA的频偏值则无法准确估计，无法将STA信道正交化，导致STA间串扰。
可选地，认为在测量的WiFi带宽内，连续的子载波正交块内信道近乎是相等的，即信道是相对平坦的信道。给各个STA发送的子载波分配不同的正交序列，使得AP侧能够将各个STA信道信息解开，进而得到符号间的相位旋转角度。
例如，如图5所示，图5是本申请实施例提供的一种多STA分别对应的正交序列的示意图。对于STA#1，第一个符号各个子载波发送的数据为
Figure PCTCN2020104898-appb-000027
对于STA#2，第一个符号各个子载波发送的数据为
Figure PCTCN2020104898-appb-000028
因为各个STA发送的子载波分配的是正交序列，所以：
Figure PCTCN2020104898-appb-000029
AP侧以天线#1为例，第一个符号各个子载波收到的数据可分别表示为：
Figure PCTCN2020104898-appb-000030
Figure PCTCN2020104898-appb-000031
Figure PCTCN2020104898-appb-000032
Figure PCTCN2020104898-appb-000033
由于前提为连续的子载波正交块内信道近乎是相等，所以
Figure PCTCN2020104898-appb-000034
Figure PCTCN2020104898-appb-000035
依次类推各个正交块，802.11ax中有234个有效子载波，要保证连续的子载波都是平坦的。在满足上述的前提条件下，对接收到的信号进行正交化，以正交STA#2的信号为例，对AP侧天线#1在第一个符号各个子载波收到的信号进行正交求和
Figure PCTCN2020104898-appb-000036
由于
Figure PCTCN2020104898-appb-000037
所以
Figure PCTCN2020104898-appb-000038
可将STA#2的信号消除掉，仅剩STA#1的信息，即：
Figure PCTCN2020104898-appb-000039
同理，对于第二个符号，AP侧可以进行上述相同的处理，得到：
Figure PCTCN2020104898-appb-000040
联合
Figure PCTCN2020104898-appb-000041
和
Figure PCTCN2020104898-appb-000042
可以计算得到2πΔf 1T。
但是，上述的前提条件连续的子载波正交块内信道近乎是相等是比较苛刻的条件，现实中很难满足，导致信道估计的精度难以保证。
为了解决上述信道估计存在的缺陷，本申请提供一种上行多站点信道估计的方法。通过发送多组用于信道估计的组训练序列，提高信道估计的准确性。
应理解，本申请实施例提供的方法可以应用于WLAN通信系统，例如，图1中所示的通信系统100。该通信系统可以包括至少一个AP和多个STA。该多个STA与AP之间的频偏不一致。
本申请实施例中以单天线的STA为例进行说明，即一个AP关联多个单天线的STA。当某个STA包括多个天线的时候，每个天线与AP的天线之间的频偏类似，所以该STA上的其他天线与AP的天线之间的信道信息的计算方式可以参考本申请实施例中涉及的该STA某个天线与AP的天线之间的信道信息的计算方式，本申请不再赘述。
还应理解，本申请实施例提供的上行多站点信道估计的方法还可以应用在多个AP的场景下，例如，图1所示的WLAN部署场景的系统中还包括另外一个AP，该另外一个AP与STA之间的通信和图1中所示的AP类似，该另一个AP与该STA之间的信道估计可以参考图1中示出的AP与STA之间的信道估计，本申请不再赘述。
还应理解，STA与AP之间进行数据传输可以发生在全带宽上(例如，20兆带宽，包括256个子载波)，本申请实施例中以一个子载波上STA与AP之间的信道估计为例进行说明，其他的子载波类似，本申请不再赘述。
还应理解，下文示出的实施例并未对本申请实施例提供的方法的执行主体的具体结构特别限定，只要能够通过运行记录有本申请实施例的提供的方法的代码的程序，以根据本申请实施例提供的方法进行通信即可，例如，本申请实施例提供的方法的执行主体可以是AP或STA，或者，是AP或STA中能够调用程序并执行程序的功能模块。
以下，不失一般性，以AP与STA之间的交互为例详细说明本申请实施例提供的上行多站点信道估计的方法。
图6是本申请实施例提供的一种上行多站点信道估计的方法的示意性流程图。执行主体包括AP和STA。为了便于理解，图6中仅示出一个STA，实际本申请实施例中与图6所示的AP关联的STA有多个STA，图中未示出。
该上行多站点信道估计的方法包括以下部分或全部的步骤。
S610，STA生成帧。
该帧中包括第一组训练序列和第二组训练序列，该第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值。求解得到的频偏值可以用于信道估计。
可选地，本申请中涉及的帧可以为数据帧、控制帧等。本申请对于帧的类型并不限制，包括上述的第一组训练序列和第二组训练序列即可。
应理解，本申请实施例中将帧中包括的训练序列分成的两组称为第一组训练序列和第二组训练序列只是举例，对本申请的保护范围不构成任何限定。例如，还可以称为第一训练序列块和第二训练序列块、第一训练序列集合和第二训练序列集合等。其中，第一组训练序列中包括一个或多个第一训练序列，第二组训练序列中包括一个或多个第二训练序列。
还应理解，本申请实施例中帧中还可以包括两个以上的训练序列组，例如，还包括第三组训练序列和第四组训练序列。这里不再一一举例说明。
具体地，该STA为与AP关联的多个STA中的任意一个。应理解，该多个STA与AP之间的频偏值不同，该多个STA中每个STA均会生成各自的训练序列，并将训练序列携带在帧中。
作为一种实现方式，上述的第一组训练序列由预设训练序列乘以P矩阵中对应于该STA的元素得到，上述的第二组训练序列由预设训练序列乘以P矩阵或P1矩阵中对应于该STA的元素得到，其中，P1矩阵为基于预设相位识别矩阵确定的矩阵，P矩阵为AP和上述多个STA已知的用于信道估计的矩阵。
可选地，在STA生成上述的帧之前，STA接收到AP发送的指示信息，该指示信息用于指示STA生成上述的帧。则图6所示的方法流程还包括S611，AP向多个STA分别发送指示信息。
例如，AP与两个STA(STA#1和STA#2)进行通信。AP向STA#1发送指示信息#1，该指示信息#1用于指示该STA#1生成帧#1，该帧#1中包括的两组训练序列用于估计STA#1到该AP的信道；AP向STA#2发送指示信息#2，该指示信息#2用于指示该STA#2生成帧#2，该帧#2中包括的两组训练序列用于估计STA#1到该AP的信道。其中指示信息#1和指示信息#2可以为同一条信息，只是接收端不一样。
可选地，该指示信息可以被包括在重复信道估计声明(repeat channel estimation announcement，RCEA)通告帧中。该RCEA帧可以为新定义的帧，或者该RECA帧可以复用目前协议中规定的触发(trigger)帧。应理解，本申请实施例中对于包括该指示信息 的帧的名称并不限定，可以称为上述的RCEA，还可以是其他的名称，这里不再一一举例说明。
一种可能的实现方式，该RCEA帧中含有1bit的指示信息，比特0表示使用目前协议规定信道估计的方法，比特1表示使用Re-CE的信道估计训练序列，该1bit的指示信息在该RCEA帧中可以称为Re-CE域。Re-CE域的定义如表1所示。
表1
Figure PCTCN2020104898-appb-000043
或者，比特1表示使用目前协议规定信道估计的方法，比特0表示使用Re-CE的信道估计训练序列；
或者，该RECA帧中包括2bit的指示信息，例如，00和11表示使用目前协议规定信道估计的方法，01和10表示表示使用Re-CE的信道估计训练序列；
或者，该RECA帧中包括2bit以上的指示信息，本申请不再一一举例说明。
应理解，考虑到信息开销，可以选择在RCEA帧中包括1bit的指示信息。
还应理解，本申请中将携带指示信息的帧称为RCEA帧只是一种举例，对本申请的保护范围不构成任何的限定。例如，还可以称为触发帧，通告帧，指示帧等，包括上述的指示信息即可。
作为一种可能的实现方式，上述的指示信息还可以用于指示STA生成帧的过程中是否使用预设相位识别矩阵。
例如，上述的RCEA帧中还含有1bit的指示信息，比特0表示使用预设相位识别矩阵，比特1表示不使用预设相位识别矩阵。
作为一种可能的实现方式，上述的指示信息还可以用于指示STA生成的第一组训练序列和所述第二组训练序列在上述帧中的排列方式。
例如，上述的RCEA帧中还含有1bit的指示信息，比特0表示第一组训练序列和所述第二组训练序列在上述帧中相邻排列，比特1表示第一组训练序列和所述第二组训练序列在上述帧中等间隔交叉排放。
例如，上述的RCEA帧中还含有2bit的指示信息，其中，2bit中的一个比特(第一比特)用于表示第一组训练序列和所述第二组训练序列在上述帧中的排列方式。可选地，第一比特值为0表示第一组训练序列和所述第二组训练序列在上述帧中相邻排列，第一比特值为1表示第一组训练序列和所述第二组训练序列在上述帧中等间隔交叉排放。2bit中的另一个比特(第二比特)用于表示第一组训练序列和第二组训练序列在上述帧中等间隔交叉排放时等间隔的个数。
可选地，第二比特值为0表示第一组训练序列和第二组训练序列在上述帧中等间隔交叉排放的间隔为1；可选地，第二比特值为1表示第一组训练序列和第二组训练序列在上述帧中等间隔交叉排放的间隔为2。
应理解，上述指示是否生成帧、指示是否使用预设相位识别矩阵、指示第一组训练序 列、所述第二组训练序列在上述帧中的排列方式和第一组训练序列和第二组训练序列等间隔交叉排列的间隔的指示信息可以分别发送，例如，AP向STA发送第一指示信息、第二指示信息、第三指示信息和第四指示信息，其中，第一指示信息用于指示是否生成帧、第二指示信息用于指示是否使用预设相位识别矩阵、第三指示信息用于指示第一组训练序列和所述第二组训练序列、第四指示信息用于指示第一组训练序列和第二组训练序列等间隔交叉排列的时候间隔的大小。本申请并不限制第一指示信息、第二指示信息和第三指示信息发送顺序的先后。但是，从信令开销小的角度考虑，AP可以采用上述的方式，用一条指示信息完成需要指示的内容。
进一步地，STA接收到上述的RCEA帧之后，查看RCEA帧中的Re-CE域，决定当前是否需要使用Re-CE训练序列完成信道估计的流程。可选地，若Re-CE域比特信息为1，则STA决定生成上述的包括第一组训练序列和第二组训练序列的帧；可选地，若Re-CE域比特信息为0，则STA决定基于已知的P矩阵完成信道估计，无需生成上述的帧。
具体地，STA生成上述的帧包括：
本申请实施例中是以单天线的STA为例进行说明，STA查看自身属于第几个STA，以及总共有多少个STA。多个STA的天线总数M(由于是以单天线为例，天线总数M可以理解为总STA数M)的是用来决定P矩阵的维度以及第一组训练序列和第二组训练序列中分别包括的训练序列的个数Q。应理解，本申请实施例中并不限制STA一定为单天线的STA，当某个STA具有多个天线的情况下，可以参考图2所示的等效为多个单天线的STA，每个单天线的STA生成上述的帧应该理解为该具有多个天线的STA生成该天线对应的帧。
例如，STA#1具有两个天线(天线#1和天线#2)，STA#2具有两个天线(天线#3和天线#4)，则STA#1生成天线#1和天线#2分别对应的帧#1和帧#2，STA#2生成天线#3和天线#4分别对应的帧#3和帧#4。STA#1生成天线#1对应的帧#1时，STA#1确定天线#1属于第一个天线，以及总共有4个天线、STA#1生成天线#2对应的帧#2时，STA#1确定天线#2属于第二个天线，以及总共有4个天线。从等效的角度考虑，STA#1等效为STA#1_1(具有天线#1)、STA#1_2(具有天线#2)，STA#2等效为STA#2_1(具有天线#3)、STA#2_2(具有天线#4)，其中，STA#1_1生成天线#1对应的帧#1，STA#1_2生成天线#2对应的帧#2，STA#2_1生成天线#3对应的帧#3，STA#2_2生成天线#4对应的帧#4。STA#1_1生成天线#1对应的帧#1时，STA#1_1确定STA#1_1属于第一个STA，以及总共有4个STA。
下文中为了便于理解，以单天线的STA为例进行说明，即天线总数M和STA总数相等，某个天线在总的天线中的顺序为具有该天线的单天线STA在总的STA中的顺序。
具体地，可以参考目前协议中M和Q之间的映射关系，如表2所示。
表2
Figure PCTCN2020104898-appb-000044
上述的M和Q之间的映射关系，还可以参考通信技术发展以后的新的协议中规定的M和Q之间的映射关系。表2中所示的M可以为多个STA的天线总数，但是应理解本申请中并不限制M只可以为多个STA的天线总数，例如，M还可以理解为多个STA的天线总数相关的数值，或者基于该多个STA的天线总数确定的某个数值。
STA在总的STA中的排序用于决定该STA的第一组训练序列和第二组训练序列中的训练序列，为预设的训练序列乘以P矩阵的第几行元素得到。其中。预设的训练序列可以为将现有的数据帧前导中的长训练序列(long training sequence，LTS)或者LTF在频域做正交扩展获得。每个STA都有自己的扩展序列，且各STA的扩展序列之间相互正交。该对长训练序列的正交扩展可以使用walsh矩阵或现有的P矩阵等，只要满足正交性即可。
例如，总共4个STA，则P矩阵选择一个4×4的矩阵，第一组训练序列内的训练序列需要4个。对于4个STA中的第一个STA，该4个训练序列分别乘以P矩阵第一行对应的4个元素，得到第一组训练序列。以此类推4个STA中的第2～4个STA，这里不再赘述。该4个STA也可以看成是分别具有两个天线的两个STA，此时P矩阵依然选择一个4×4的矩阵，第一组训练序列内的训练序列需要4个。对于4个天线中的第一个天线，该4个训练序列分别乘以P矩阵第一行对应的4个元素，得到第一组训练序列。以此类推4个天线中的第2～4个天线，以下对于某个STA具有多天线的情况不再赘述。
完成第一组训练序列的生成之后，第二组训练序列做相同处理即可，然后将生成的第一组训练序列和第二组训练序列按照一定的顺序排放在帧中发送给AP。具体地，STA#1生成的第一组训练序列包括Q个训练序列(预设训练序列×P 11、预设训练序列×P 12、…、预设训练序列×P 1Q)；第二组训练序列包括Q个训练序列(预设训练序列×P 21、预设训练序列×P 22、…、预设训练序列×P 2Q)。第一组训练序列占用帧中的Q个第一位置，第二组训练序列占用所述帧中的Q个第二位置。
一种可能的实现方式，上述的Q个第一位置和Q个第二位置在帧中依次先后排列。即STA生成的第一组训练序列和第二组训练序列依次相邻排放在帧中，如图7(a)所示，图7是本申请实施例提供的帧示意图；
从图7(a)中可以看出，第一组训练序列中包括的Q个训练序列作为一个整体排列在第二组训练序列包括的Q个训练序列之前。
另一种可能的实现方式，上述的Q个第一位置和Q个第二位置在帧中交叉相邻排列。 即STA生成的第一组训练序列和第二组训练序列中包括的训练序列交叉相邻排放在帧中，如图7(b)所示。从图7(b)中可以看出，第一组训练序列中包括的Q个训练序列和第二组训练序列中包括的Q个训练序列一个间隔一个地排列。
又一种可能的实现方式，上述的Q个第一位置和Q个第二位置在帧中等间隔交叉排列。即STA生成的第一组训练序列和第二组训练序列中包括的训练序列等间隔交叉排放在帧中，如图7(c)所示。从图7(b)中可以看出，第一组训练序列中包括的Q个训练序列和第二组训练序列中包括的Q个训练序列两个间隔两个地排列。
应理解，本申请实施例中当Q个第一位置和Q个第二位置在帧中等间隔交叉排列时，可以如图7(b)所示一个第一位置和一个第二位置交叉排列，也可以如图7(c)所示两个第一位置和两个第二位置交叉排列，还可以N个第一位置和N个第二位置交叉排列(N小于Q)，本申请不再赘述。具体地，第一组训练序列和第二组训练序列等间隔交叉排列具体间隔方式可以从AP侧能够识别出不同的STA的频偏值为准进行设计。
可选地，为了更准确地区分计算得到的频偏值对应不同的STA，可以在上述的第二组训练序列中增加相位识别信息。即第二组训练序列由预设训练序列乘以P1矩阵中对应于所述STA的元素得到。
一种可能的实现方式，P1矩阵为预设的相位识别矩阵左乘于P矩阵之后得到的矩阵。
另一种可能的实现方式，P1矩阵为具有相位识别功能的预设的相位识别矩阵。
应理解，本申请实施例中对于P1矩阵的具体形式并不限制。
为了便于理解STA生成上述的帧的流程，下面以两个STA与AP通信为例进行说明。
STA#1接收到AP发送的RCEA帧#1，根据RCEA帧#1中Re-CE域的比特值(例如，比特值为1)确定需要生成帧#1。
具体地，STA#1根据RCEA帧#1中的信息获知STA#1为第一个STA，以及当前有两个STA会同时上行MU-MIMO。应理解，本申请实施例中对于STA如何获知同时上行MU-MIMO的STA的总数以及自身在总的STA中所处的顺序并不限定，可以是沿用目前协议中的规定，也可以是采用未来WiFi技术发展之后的方案。
根据表2所示，当STA的总数为2的情况下，STA#1生成的第一组训练序列中应该包括两个训练序列，且P矩阵的维度为2，本申请中假设P矩阵为
Figure PCTCN2020104898-appb-000045
该两个训练序列分别乘以P矩阵中第一行的两个元素，即乘以[1 -1]。两个训练序列中的第一个训练序列乘以1，两个训练序列中的第二个训练序列乘以-1；STA#1生成第二组训练序列的流程与上述生成第一组训练序列类似，这里不再赘述。
同理，STA#2接收到AP发送的RCEA帧#2，根据RCEA帧#2中Re-CE域的比特值确定需要生成帧#2。
具体地，STA#2根据RCEA帧#2中的信息获知STA#2为第二个STA，以及当前有两个STA会同时上行MU-MIMO。
根据表2所示，当STA的总数为2的情况下，STA#2生成的第一组训练序列中应该包括两个训练序列，且P矩阵的维度为2，本申请中假设P矩阵为
Figure PCTCN2020104898-appb-000046
该两个训练 序列分别乘以P矩阵中第二行的两个值，即乘以[1 1]。两个训练序列中的第一个训练序列乘以1，两个训练序列中的第二个训练序列乘以1；STA#2生成第二组训练序列的流程与上述生成第一组训练序列类似，这里不再赘述。
一种可能的实现方式，STA#1和STA#2分别将生成的第一组训练序列和第二组训练序列，依次相邻排放在各自即将发送的帧中，如图8(a)所示，图8是本申请实施例提供的两个STA生成的帧的示意图；
另一种可能的实现方式，STA#1生成的第一组训练序列和第二组训练序列中包括的训练序列交叉排放在即将发送的帧中；STA#2生成的第一组训练序列和第二组训练序列中包括的训练序列交叉排放在即将发送的帧中，如图8(b)所示。
可选地，为了更准确地区分不同的STA可以在上述的第二组训练序列中增加相位识别信息，例如，上述的STA#1生成第二组训练序列的时候，引入相位识别矩阵P Phase_identify，该P Phase_identify可以是基于P矩阵生成的，例如：
Figure PCTCN2020104898-appb-000047
即生成第二组训练序列的时候上述的两个训练序列乘以P Phase_identify中的第一行的两个元素。
进一步地，STA生成了上述的第一组训练序列和第二组训练序列之后，将该第一组训练序列和第二组训练序列发送给AP。具体地，STA向AP发送帧，该帧中包括生成的第一组训练序列和第二组训练序列，即图6所示的方法流程还包括S620，STA向AP发送帧。
具体地，STA向AP发送上述的帧可以是在规定的时间间隔之后，M个STA同时发送帧，并且每个STA发送的帧中包括该STA生成的第一组训练序列和第二组训练序列。应理解，本申请对于该规定的时间间隔并不限制。
应理解，上述的M个STA分别向AP发送帧，各自发送的帧中包括各自生成的第一组训练序列和第二组训练序列。从图7中可以看出，STA生成的第一组训练序列和第二组训练序列在帧中包括多种不同的排放方式。则AP接收到的帧包括图7所示的多种可能的形式。
具体地，M个STA分别发送的M个帧中包括的M个第一组训练序列经过M个STA分别与AP之间的信道发送至AP，AP侧接收到的为第一信息矩阵；同理，M个STA分别发送的M个帧中包括的M个第二组训练序列经过M个STA分别与AP之间的信道发送至AP，AP接收到的为第二信息矩阵。其中，第一信息矩阵和第二信息矩阵用于求解所述M个STA分别与所述AP之间的频偏值。
为了便于理解，上述的第一信息矩阵可以表示为M个第一组训练序列组成的训练序列矩阵与M个STA分别与所述AP之间的信道信息组成的信道信息矩阵之间的乘积；上述的第二信息矩阵可以表示为M个第二组训练序列组成的训练序列矩阵与M个STA分别与所述AP之间的信道信息组成的信道信息矩阵之间的乘积。
应理解，本申请实施例中将M个STA分别与所述AP之间的信道信息组成的矩阵称为信道信息矩阵只是一种举例，对本申请的保护范围不构成任何限定。例如，还可以称为信道估计矩阵、信道矩阵等。
进一步地，AP能够计算得到M个STA分别与AP之间的频偏值，即图6所示的方法 流程还包括S630，AP计算频偏值。本申请实施例提供的上行多站点信道估计的方法，AP计算频偏值包括以下几种可能的情况：
情况一：
AP接收到的M个STA发送的帧如图7(a)中所示。当不考虑M个STA中每个STA与AP之间的频偏时，上述的第一信息矩阵可以表示为：
Figure PCTCN2020104898-appb-000048
但是，本申请实施例主要考虑各个STA与AP之间有不同的频偏。例如，M个STA与AP之间的频偏分别为Δf 1、Δf 2、…、Δf M，M个STA中每个STA发送的训练序列会由于频偏，在第一个符号之后的每个符号上发送的训练序列相对于第一个符号上发送的训练序列会产生相位旋转的累加，所以某一符号Q上发送的训练序列相对于第一个符号上发送的训练序列的相位旋转角度为j2πΔf(Q-1)T。则第一信息矩阵表示为：
Figure PCTCN2020104898-appb-000049
同理，第二信息矩阵表示为：
Figure PCTCN2020104898-appb-000050
对上述第一信息矩阵(式1-2)求逆之后，左乘于上述第二信息矩阵得到：
Figure PCTCN2020104898-appb-000051
从式1-3可以看出第一信息矩阵求逆之后，左乘于所述第二信息矩阵得到的结果具有标准的特征值分解性质，利用特征值分解得到A phase，即可求解得到特征值：
Figure PCTCN2020104898-appb-000052
Figure PCTCN2020104898-appb-000053
基于上述的特征值计算得到M个STA与AP之间的频偏值分别为Δf 1、Δf 2、…、Δf M。
情况二：
AP接收到的M个STA发送的帧如图7(a)中所示，且S610中STA是基于P1矩阵生成第二组训练序列。当不考虑M个STA中每个STA与AP之间的频偏时上述的第一信息矩阵可以表示为上述的式1-1。
但是，本申请实施例主要考虑各个STA与AP之间有不同的频偏。例如，M个STA与AP之间的频偏分别为Δf 1、Δf 2、…、Δf M，M个STA中每个STA发送的训练序列会由于频偏，在第一个符号之后的每个符号上发送的训练序列相对于第一个符号上发送的训练序列会产生相位旋转的累加，所以某一符号Q上发送的训练序列相对于第一个符号上发送的训练序列的相位旋转角度为j2πΔf(Q-1)T。则第一信息矩阵表示上述的式1-2。
具体地，第二组训练序列为预设训练序列乘以P1矩阵得到的，所以第二信息矩阵表示为：
Figure PCTCN2020104898-appb-000054
对所述第一信息矩阵(式1-2)求逆之后，左乘于第二信息矩阵得到：
Figure PCTCN2020104898-appb-000055
从式1-7可以看出第一信息矩阵求逆之后，左乘于第二信息矩阵得到的结果具有标准的特征值分解性质，利用特征值分解得到
Figure PCTCN2020104898-appb-000056
即可求解得到特征值：
Figure PCTCN2020104898-appb-000057
Figure PCTCN2020104898-appb-000058
基于上述的特征值计算得到M个STA与AP之间的频偏值分别为Δf 1、Δf 2、…、Δf M。
针对情况二需要说明的是：由于特征值分解时，可能会出现特征值由大到小排列求出，这样就无法区分各个特征值对应的STA，所以通过增加了相位识别角度，则可以对求出的特征值求角度，得到各个特征值对应的角度值。在上行MU-MIMO时，最新的802.11ax协议要求STA做到350Hz以内的频偏预补偿，也就是说STA与AP间的频偏值不会超过350Hz，正常一个符号16us。当有两个STA与AP通信时，基本上求得的角度值(若不算上相位识别角度)为2πΔf 12T<4.032度，可以给STA#1增加90度的相位识别角度，这样在求得的特征值角度值中找到与90度值最接近的那个特征值即为STA#1对应的特征值。同理，对于STA#2，同样也有2πΔf 22T<4.032度，若给STA#2增加180度相位识别角度，则在求得的特征值角度值中找到与180度值最接近的那个特征值即为STA#2对应的特征值。应理解，本申请中并不限定相位识别角度如何设定，可根据需要设置。这样就可以简单的得到STA#1和STA#2的相位旋转角度。
情况三：
AP接收到的M个STA发送的帧如图7(b)中所示的情况下。当不考虑M个STA中每个STA与AP之间的频偏时上述的第一信息矩阵可以表示为：
Figure PCTCN2020104898-appb-000059
但是，本申请主要考虑各个STA与AP之间有不同的频偏。例如，M个STA与AP之间的频偏分别为Δf 1、Δf 2、…、Δf M，M个STA中STA发送的训练序列会由于频偏，以及交叉排放的缘故，符号之间上发送的训练序列的相位旋转会跳跃两个符号，所以某一符号Q上发送的训练序列相对于第一个符号上发送的训练序列的相位旋转角度为j2πΔf(Q-1)2T。则第一信息矩阵表示为：
Figure PCTCN2020104898-appb-000060
同理，第二信息矩阵表示为：
Figure PCTCN2020104898-appb-000061
对所述第一信息矩阵求逆(式1-5)之后，左乘于所述第二信息矩阵得到：
Figure PCTCN2020104898-appb-000062
从式1-6可以看出第一信息矩阵求逆之后，左乘于所述第二信息矩阵得到的结果具有标准的特征值分解性质，利用特征值分解得到
Figure PCTCN2020104898-appb-000063
即可求解得到特征值：
Figure PCTCN2020104898-appb-000064
Figure PCTCN2020104898-appb-000065
基于上述的特征值计算得到M个STA与AP之间的频偏值分别为Δf 1、Δf 2、…、Δf M。
当AP接收到的M个STA发送的帧如图7(c)中所示的情况下，能够求解得到特征值：
Figure PCTCN2020104898-appb-000066
基于该特征值计算得到M个STA与AP之间的频偏值分别为Δf 1、Δf 2、…、Δf M；当N个第一位置和N个第二位置交叉排列(N小于Q)的情况下，能够求解得到特征值：
Figure PCTCN2020104898-appb-000067
基于该特征值计算得到M个STA与AP之间的频偏值分别为Δf 1、Δf 2、…、Δf M。具体求解过程与情况三所示的类似，这里不再赘述。
针对情况三需要说明的是：若STA数更多时，2πΔf 1QT最大的角度值为2πΔf 1QT≤2.016Q度，会造成即使如情况二所示的增加相位识别信息也无法识别区分各个STA的频偏值。以八天线AP和八个单天线STA组成的MU-MIMO系统为例，当STA 数为8时，根据映射表2，Q＝8，则在AP能够得到的特征值角度2πΔf 18T≤16.265度。相位识别信息可用的范围为360度，八个STA均分就是360/8＝45度。如果想要STA的特征值不判定错误，那么需要特征值的角度小于45/2＝22.5度才可以，这样才能无差错的区分出是哪个STA的特征值角度。当前8个STA特征值角度最大可达16度，已经比较接近22.5度。当STA数更多时，或者当有很大的系统噪声，导致特征值计算的误差时，就会导致STA角度的误判，有一定风险。当前最新的802.11ax仅最大支持8个STA，可以一定程度上保证性能。但为了保证扩展性，本实施例提出交叉的训练序列组排放方式，即图8(b)的排放方式。从而使得特征值的角度值与STA个数无关，因为特征值永远都是
Figure PCTCN2020104898-appb-000068
所以特征值角度2πΔf 1T≤2.016度，远小于360/M度，减少误判可能。
情况四：
AP接收到的M个STA发送的数据帧如图7(b)中所示，且S610中STA是基于P1矩阵生成第二组训练序列。当不考虑M个STA中每个STA与AP之间的频偏时上述的第一信息矩阵可以表示为上述的式1-4。
但是，本申请主要考虑各个STA与AP之间有不同的频偏。例如，M个STA与AP之间的频偏分别为Δf 1、Δf 2、…、Δf M，M个STA中STA发送的训练序列会由于频偏，以及交叉排放的缘故，符号之间上发送的训练序列的相位旋转会跳跃两个符号，所以某一符号Q上发送的训练序列相对于第一个符号上发送的训练序列的相位旋转角度为j2πΔf(Q-1)2T。则第一信息矩阵表示为上述的式1-5。
具体地，第二组训练序列为预设训练序列乘以P1矩阵得到的，所以第二信息矩阵表示为：
Figure PCTCN2020104898-appb-000069
对所述第一信息矩阵(式1-5)求逆之后，左乘于所述第二信息矩阵得到：
Figure PCTCN2020104898-appb-000070
从式1-8可以看出第一信息矩阵求逆之后，左乘于所述第二信息矩阵得到的结果具有标准的特征值分解性质，利用特征值分解得到
Figure PCTCN2020104898-appb-000071
即可求解得到特征值：
Figure PCTCN2020104898-appb-000072
基于上述的特征值计算得到M个STA与AP之间的频偏值分别为Δf 1、Δf 2、…、Δf M。
相比于上述的图4和图5中所示的信道估计，本申请提供的上行多站点信道估计的方法能够计算得到更为准确的频偏值，再基于计算得到的频偏值进行信道估计时能够提高信道估计的准确性。
进一步地，AP求解得到上述的M个STA分别与AP之间的频偏值之后，能够基于该频偏值修正上文所示的P矩阵，得到修正后的P矩阵。
具体地，图6所示的方法流程还包括S640，AP基于修正后的矩阵进行信道估计，包括以下三种情况：
情况一：
AP将修正后的P矩阵求逆之后，右乘于第一信息矩阵得到信道信息矩阵，完成信道估计。
情况二：
AP将修正后的P矩阵左乘上述的A phase矩阵之后的矩阵，求逆右乘于第二信息矩阵得到信道信息矩阵，完成信道估计；或者，
AP将修正后的P矩阵左乘上述的
Figure PCTCN2020104898-appb-000073
矩阵之后的矩阵，求逆右乘于第二信息矩阵得到信道信息矩阵，完成信道估计；或者，
AP将修正后的P矩阵左乘上述的
Figure PCTCN2020104898-appb-000074
矩阵之后的矩阵，求逆右乘于第二信息矩阵得到信道信息矩阵，完成信道估计；或者，
AP将修正后的P矩阵左乘上述的
Figure PCTCN2020104898-appb-000075
矩阵之后的矩阵，求逆右乘于第二信息矩阵得到信道信息矩阵，完成信道估计。
情况三：
AP将修正后的P矩阵求逆之后，右乘于第一信息矩阵得到第一信道信息；
AP将修正后的P矩阵左乘上述的A phase、
Figure PCTCN2020104898-appb-000076
或
Figure PCTCN2020104898-appb-000077
矩阵，求逆右乘于第二信息矩阵得到第二信道信息，计算第一信道信息和第二信道信息的加权平均值得到信道信息矩阵，完成信道估计。其中，计算第一信道信息和第二信道信息的加权平均值可以理解为计算第一信道信息和第二信道信息的算术平均值或几何平均值等。
应理解，本申请实施例中对于计算第一信道信息和第二信道信息的平均值的具体方式并不限制。还应理解，以第一信道信息和第二信道信息的平均值作为需要计算的信道信息矩阵时，能够提高3dB的精度，例如，信噪比提高3dB，或者发射功率提高3dB，或者信 道估计准确度提高3dB。
为了便于理解AP完成信道估计的流程，下面两个STA与AP通信为例进行说明，其中，AP包括天线#1和天线#2，STA#1和STA#2为单天线STA，且STA#1和STA#2与AP之间的频偏值分别为Δf 1和Δf 2，P矩阵为
Figure PCTCN2020104898-appb-000078
对应于上述S630中所示的四种情况，AP估计两个STA的信道信息包括以下四种情况：
情况一：
AP接收到的STA#1和STA#2分别发送的帧的形式如图8(a)所示。AP的天线#1收到的数据是STA#1的数据经历信道h 11与STA#2的数据经历信道h 12两部分数据的和。AP的天线#2收到的数据是STA#1的数据经历信道h 21与STA#2的数据经历信道h 22两部分数据的和。对于各个训练序列符号来看，由于各STA相对于AP有不同的频偏，那么STA#1的第二个符号上发送的数据应该是-1，但是由于相位旋转，变成了
Figure PCTCN2020104898-appb-000079
同样地，STA#2的第二个符号上发送的数据应该是1，但是由于相位旋转，变成了
Figure PCTCN2020104898-appb-000080
则AP收到的第一信息矩阵为：
Figure PCTCN2020104898-appb-000081
AP收到的第二信息矩阵为：
Figure PCTCN2020104898-appb-000082
AP用第一信息矩阵求逆左乘于第二信息矩阵上，则可得到相应的特征值标准形式：
Figure PCTCN2020104898-appb-000083
利用特征值分解定理，可得到特征值
Figure PCTCN2020104898-appb-000084
和
Figure PCTCN2020104898-appb-000085
求其特征值的角度然后除以相应的系数则可以得到Δf 1和Δf 2。
由Δf 1和Δf 2可以得到修正后的P矩阵P fix为
Figure PCTCN2020104898-appb-000086
基于该P fix进行信道估计包括：
将该P fix求逆右乘于上述的第一信息矩阵(式2-1)则可以得到
Figure PCTCN2020104898-appb-000087
或者，将该P fix左乘式2-2中的特征值矩阵
Figure PCTCN2020104898-appb-000088
之后求逆右乘于上述的第二信息矩阵(式2-2)则可以得到
Figure PCTCN2020104898-appb-000089
或者，
该P fix求逆右乘于上述的第一信息矩阵(式2-1)则可以得到
Figure PCTCN2020104898-appb-000090
该P fix左乘式2-2中的特征值矩阵
Figure PCTCN2020104898-appb-000091
之后求逆右乘于上述的第二信息矩阵(式2-2)则可以得到
Figure PCTCN2020104898-appb-000092
求
Figure PCTCN2020104898-appb-000093
和
Figure PCTCN2020104898-appb-000094
的平均值得到
Figure PCTCN2020104898-appb-000095
信道估 计时会有噪声的影响，所以结合两次的信道估计求平均，可以起到增加3dB准确度的效果，可理解为发射功率，或者信噪比提高了3dB，或者信道估计准确度提高3dB。在未考虑噪声时
Figure PCTCN2020104898-appb-000096
和
Figure PCTCN2020104898-appb-000097
应是准确的信道信息矩阵。
情况二：
AP接收到的STA#1和STA#2分别发送的帧的形式如图8(a)所示，且STA#1和STA#2分别基于P1矩阵生成各自训练序列中的第二组训练序列。P1矩阵为
Figure PCTCN2020104898-appb-000098
其中，
Figure PCTCN2020104898-appb-000099
称为相位识别矩阵。
则AP收到的第一信息矩阵为：
Figure PCTCN2020104898-appb-000100
AP收到的第二信息矩阵为：
Figure PCTCN2020104898-appb-000101
AP用第一信息矩阵求逆左乘于第二信息矩阵上，则可得到相应的特征值标准形式：
Figure PCTCN2020104898-appb-000102
利用特征值分解定理，可得到特征值
Figure PCTCN2020104898-appb-000103
和
Figure PCTCN2020104898-appb-000104
求其特征值的角度phaseshift 1+2πΔf 12T和phaseshift 2+2πΔf 22T，然后进一步除以系数就可以得Δf 1和Δf 2。
由Δf 1和Δf 2可以得到修正后的P矩阵P fix，并基于该P fix进行信道估计与情况一中所示的类似，这里不再赘述。
情况三：
AP接收到的M个STA发送的帧如图8(b)中所示的情况下。
则AP收到的第一信息矩阵为：
Figure PCTCN2020104898-appb-000105
AP收到的第二信息矩阵为：
Figure PCTCN2020104898-appb-000106
AP用第一信息矩阵求逆左乘于第二信息矩阵上，则可得到相应的特征值标准形式：
Figure PCTCN2020104898-appb-000107
利用特征值分解定理，可得到特征值
Figure PCTCN2020104898-appb-000108
和
Figure PCTCN2020104898-appb-000109
求其特征值的角度然后除以相应的系数则可以得到Δf 1和Δf 2。
由Δf 1和Δf 2可以得到修正后的P矩阵P fix，并基于该P fix进行信道估计与情况一中所示的类似，这里不再赘述。
情况四：
AP接收到的STA#1和STA#2分别发送的帧的形式如图8(b)所示，且STA#1和STA#2分别基于P1矩阵生成各自训练序列中的第二组训练序列。
则AP收到的第一信息矩阵为：
Figure PCTCN2020104898-appb-000110
AP收到的第二信息矩阵为：
Figure PCTCN2020104898-appb-000111
P用第一信息矩阵求逆左乘于第二信息矩阵上，则可得到相应的特征值标准形式：
Figure PCTCN2020104898-appb-000112
利用特征值分解定理，可得到特征值
Figure PCTCN2020104898-appb-000113
和
Figure PCTCN2020104898-appb-000114
求其特征值的角度phaseshift 1+2πΔf 1T和phaseshift 2+2πΔf 2T，然后进一步除以系数就可以得Δf 1和Δf 2。
由Δf 1和Δf 2可以得到修正后的P矩阵P fix，并基于该P fix进行信道估计与情况一中所示的类似，这里不再赘述。
应理解，上述的情况一至情况四均以STA发送的帧中包括两组训练序列为例进行说明。但是本申请实施例中并不限定STA发送的帧中只能包括两组训练序列，例如，还可以包括4组训练序列，则在计算频偏值的过程中将4组训练序列分为两个两组训练序列，分别基于两个两组训练序列计算频偏值，再求计算得到的两组频偏值的平均值，将平均值作为计算得到的频偏值。具体流程这里不再赘述。
具体地，本申请实施例提供的上行多站点信道估计的方法，能够更准确估计出信道信息矩阵。其中，信道信息矩阵可以用于以下两中情况下：
情况一：
STA上行MU-MIMO发送了数据负载，AP侧利用信道信息矩阵求逆左乘于数据矩阵上，则可以将数据准确正交均衡，区分出各个STA的数据。
以两个STA与AP通信为例进行说明。
当图8所示的数据帧中包括数据负载，即训练序列后面的符号上承载数据
Figure PCTCN2020104898-appb-000115
则在AP侧接收到的数据负载矩阵表示为：
Figure PCTCN2020104898-appb-000116
由于信道信息矩阵已通过数据帧中数据负载前的训练序列估计得到，则AP侧区分出各个STA的数据为：
Figure PCTCN2020104898-appb-000117
情况二：
AP使用该信道进行下行MU-MIMO数据的预编码，即将该信道求逆左乘于发送的数 据上，相当于AP侧的预均衡。使得多个STA收到的数据相互不串扰。
以两个STA与AP通信为例进行说明。
AP发送的数据可表示为：
Figure PCTCN2020104898-appb-000118
在STA侧收到的数据为：
Figure PCTCN2020104898-appb-000119
还应理解，上述方法实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
上面结合图6详细介绍了本申请实施例提供的上行多站点信道估计的方法，下面结合图9-图12详细介绍本申请实施例提供的上行多站点信道估计的装置。
参见图9，图9是本申请提出的上行多站点信道估计的装置90的示意图。如图9所示，装置90包括处理单元910和发送单元920。
处理单元910，用于生成帧，帧中包括第一组训练序列和第二组训练序列，第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值，频偏值用于信道估计；
发送单元920，用于向AP发送帧。
装置90和方法实施例中的STA完全对应，装置90可以是方法实施例中的STA，或者方法实施例中的STA内部的芯片或功能模块。装置90的相应单元用于执行图6所示的方法实施例中由STA执行的相应步骤。
其中，装置90中的处理单元910执行方法实施例中STA内部实现或处理的步骤。例如，执行图6中生成帧的步骤S610。
发送单元920执行方法实施例中STA发送的步骤。例如，执行图6中向AP发送帧的步骤S620；
装置90还可以包括接收单元，用于执行STA接收的步骤，例如，接收其他设备发送的信息。发送单元920和接收单元可以组成收发单元，同时具有接收和发送的功能。其中，处理单元910可以是处理器。发送单元920可以是发射器，接收单元可以是接收器。接收器和发射器可以集成在一起组成收发器。
参见图10，图10是适用于本申请实施例的STA 1000的结构示意图。该STA1000可应用于图1所示出的系统中。为了便于说明，图10仅示出了STA的主要部件。如图10所示，STA 1000包括处理器(对应于图9中所示的处理单元910)、存储器、控制电路、天线以及输入输出装置(对应于图9中所示的发送单元920)。处理器用于控制天线以及输入输出装置收发信号，存储器用于存储计算机程序，处理器用于从存储器中调用并运行该计算机程序，以执行本申请提出的上行多站点信道估计的方法中由STA执行的相应流程和/或操作。此处不再赘述。
本领域技术人员可以理解，为了便于说明，图10仅示出了一个存储器和处理器。在实际的STA中，可以存在多个处理器和存储器。存储器也可以称为存储介质或者存储设 备等，本申请实施例对此不做限制。
参见图11，图11是本申请提出的上行多站点信道估计的装置1100的示意图。如图11所示，装置1100包括接收单元1110和处理单元1120。
接收单元1110，用于接收多个STA分别发送的帧，所述帧中包括第一组训练序列和第二组训练序列，所述第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值；
处理单元1120，用于基于所述多个STA分别与所述AP之间的频偏值，进行信道估计。
装置1100和方法实施例中的AP完全对应，装置1100可以是方法实施例中的AP，或者方法实施例中的AP内部的芯片或功能模块。装置1100的相应单元用于执行图6所示的方法实施例中由AP执行的相应步骤。
其中，装置1100中的接收单元1110执行方法实施例中AP发送的步骤。例如，执行图6中接收STA发送帧的步骤S620。
装置1100中的处理单元1120执行方法实施例中AP内部实现或处理的步骤。例如，执行图6中计算频偏值的步骤S630，以及执行图6中进行信道估计的步骤S640。
装置1100还可以包括发送单元，用于执行AP发送的步骤，向其他设备发送信息，例如，执行图6中向STA发送指示信息的步骤S611。接收单元1110和发送单元可以组成收发单元，同时具有接收和发送的功能。其中，处理单元1120可以是处理器。发送单元可以是发射器。接收单元1110可以是接收器。接收器和发射器可以集成在一起组成收发器。
参见图12，图12是适用于本申请实施例的AP 1200的结构示意图，可以用于实现上述上行多站点信道估计的方法中的AP的功能。可以为AP的结构示意图。
AP包括1210部分以及1220部分。1210部分主要用于射频信号的收发以及射频信号与基带信号的转换；1220部分主要用于基带处理，对定位管理组件进行控制等。1210部分通常可以称为收发单元、收发机、收发电路、或者收发器等。1220部分通常是定位管理组件的控制中心，通常可以称为处理单元，用于控制定位管理组件执行上述方法实施例中AP侧的处理操作。
1210部分的收发单元，也可以称为收发机或收发器等，其包括天线和射频单元，其中射频单元主要用于进行射频处理。可选地，可以将1210部分中用于实现接收功能的器件视为接收单元，将用于实现发送功能的器件视为发送单元，即810部分包括接收单元和发送单元。接收单元也可以称为接收机、接收器、或接收电路等，发送单元可以称为发射机、发射器或者发射电路等。
1220部分可以包括一个或多个单板，每个单板可以包括一个或多个处理器和一个或多个存储器。处理器用于读取和执行存储器中的程序以实现基带处理功能以及对定位管理组件的控制。若存在多个单板，各个单板之间可以互联以增强处理能力。作为一种可选的实施方式，也可以是多个单板共用一个或多个处理器，或者是多个单板共用一个或多个存储器，或者是多个单板同时共用一个或多个处理器。
应理解，图12仅为示例而非限定，上述包括收发单元和处理单元的AP可以不依赖于图12所示的结构。
还应理解，图12所示的AP 1200能够实现图6的方法实施例中涉及的AP功能。AP1200中的各个单元的操作和/或功能，分别为了实现本申请方法实施例中由AP执行的相应流程。为避免重复，此处适当省略详述描述。图12示例的AP的结构仅为一种可能的形态，而不应对本申请实施例构成任何限定。本申请并不排除未来可能出现的其他形态的AP结构的可能。
本申请实施例还提供一种通信系统，其包括前述的STA和AP。
本申请还提供了一种计算机可读存储介质，该计算机可读存储介质中存储有指令，当该指令在计算机上运行时，使得计算机执行上述如图6所示的方法中STA执行的各个步骤。
本申请还提供了一种计算机可读存储介质，该计算机可读存储介质中存储有指令，当该指令在计算机上运行时，使得计算机执行上述如图6所示的方法中AP执行的各个步骤。
本申请还提供了一种包含指令的计算机程序产品，当该计算机程序产品在计算机上运行时，使得计算机执行如图6所示的方法中STA执行的各个步骤。
本申请还提供了一种包含指令的计算机程序产品，当该计算机程序产品在计算机上运行时，使得计算机执行如图6所示的方法中AP执行的各个步骤。
本申请还提供一种芯片，包括处理器。该处理器用于读取并运行存储器中存储的计算机程序，以执行本申请提供的上行多站点信道估计的方法中由STA执行的相应操作和/或流程。可选地，该芯片还包括存储器，该存储器与该处理器通过电路或电线与存储器连接，处理器用于读取并执行该存储器中的计算机程序。进一步可选地，该芯片还包括通信接口，处理器与该通信接口连接。通信接口用于接收需要处理的数据和/或信息，处理器从该通信接口获取该数据和/或信息，并对该数据和/或信息进行处理。该通信接口可以是该芯片上的输入/输出接口、接口电路、输出电路、输入电路、管脚或相关电路等。所述处理器也可以体现为处理电路或逻辑电路。
本申请还提供一种芯片，包括处理器。该处理器用于读取并运行存储器中存储的计算机程序，以执行本申请提供的上行多站点信道估计的方法中由AP执行的相应操作和/或流程。可选地，该芯片还包括存储器，该存储器与该处理器通过电路或电线与存储器连接，处理器用于读取并执行该存储器中的计算机程序。进一步可选地，该芯片还包括通信接口，处理器与该通信接口连接。通信接口用于接收需要处理的数据和/或信息，处理器从该通信接口获取该数据和/或信息，并对该数据和/或信息进行处理。该通信接口可以是该芯片上的输入/输出接口、接口电路、输出电路、输入电路、管脚或相关电路等。所述处理器也可以体现为处理电路或逻辑电路。
应理解，上述的芯片也可以替换为芯片系统，这里不再赘述。
本申请中的术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可 以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(read-only memory，ROM)、随机存取存储器(random access memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
另外，本申请中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系；本申请中术语“至少一个”，可以表示“一个”和“两个或两个以上”，例如，A、B和C中至少一个，可以表示：单独存在A，单独存在B，单独存在C、同时存在A和B，同时存在A和C，同时存在C和B，同时存在A和B和C，这七种情况。
另外，本申请中术语“左乘/右乘”，描述矩阵之间的计算方式。例如，矩阵A左乘矩阵B，得到矩阵BA，矩阵A右乘矩阵B，得到矩阵AB；本申请中术语“左乘于/右乘于”，描述矩阵之间的计算方式。例如，矩阵A左乘于矩阵B，得到矩阵AB，矩阵A右乘于矩阵B，得到矩阵BA。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (33)

  1. 一种上行多站点信道估计的方法，应用于与接入点AP通信的多个站点STA中的任意一个STA，其特征在于，包括：
    所述STA生成帧，所述帧中包括第一组训练序列和第二组训练序列，所述第一组训练序列和第二组训练序列用于求解所述STA与所述AP之间频偏值，所述频偏值用于信道估计；
    所述STA向所述AP发送所述帧。
  2. 根据权利要求1所述的方法，其特征在于，在所述STA生成所述帧之前，所述方法还包括：
    所述STA接收来自所述AP的指示信息，所述指示信息用于指示所述STA生成所述帧。
  3. 根据权利要求2所述的方法，其特征在于，所述指示信息还用于指示所述STA生成所述帧的过程是否使用预设相位识别矩阵，和/或，
    所述指示信息还用于指示所述第一组训练序列和所述第二组训练序列在所述帧中的排列方式。
  4. 根据权利要求1-3中任一项所述的方法，其特征在于，所述第一组训练序列由预设训练序列乘以P矩阵中对应于所述STA的元素得到，
    所述第二组训练序列由预设训练序列乘以所述P矩阵或P1矩阵中对应于所述STA的元素得到，
    其中，所述P1矩阵为基于预设相位识别矩阵确定的矩阵，所述P矩阵为所述AP和所述多个STA已知的用于信道估计的矩阵。
  5. 根据权利要求1-4中任一项所述的方法，其特征在于，所述第一组训练序列占用所述帧中的Q个第一位置，
    所述第二组训练序列占用所述帧中的Q个第二位置，
    其中，所述Q个第一位置和所述Q个第二位置依次先后排列；或者，所述Q个第一位置和Q个第二位置等间隔交叉排列，所述Q为与M满足预设的对应关系的整数，所述M为所述多个STA的天线总数。
  6. 根据权利要求1-5中任一项所述的方法，其特征在于，所述第一组训练序列中包括一个或多个第一训练序列，所述第二组训练序列中包括一个或多个第二训练序列。
  7. 一种上行多站点信道估计的方法，应用于与多个站点STA通信的接入点AP，其特征在于，包括：
    所述AP接收所述多个STA分别发送的帧，所述帧中包括第一组训练序列和第二组训练序列，所述第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值；
    所述AP基于所述多个STA分别与所述AP之间的频偏值，进行信道估计。
  8. 根据权利要求7所述的方法，其特征在于，所述方法还包括：
    所述AP向所述STA发送指示信息，所述指示信息用于指示所述STA生成所述帧。
  9. 根据权利要求8所述的方法，其特征在于，所述指示信息还用于指示所述STA生 成所述帧的过程是否使用预设相位识别矩阵，和/或，
    所述指示信息还用于指示所述第一组训练序列和所述第二组训练序列在所述帧中的排列方式。
  10. 根据权利要求7-9中任一项所述的方法，其特征在于，所述第一组训练序列由预设训练序列乘以P矩阵中对应于所述STA的元素得到，
    所述第二组训练序列由预设训练序列乘以P矩阵或P1矩阵中对应于所述STA的元素得到，
    其中，所述P1矩阵为基于预设相位识别矩阵确定的矩阵，所述P矩阵为所述AP和所述多个STA已知的用于信道估计的矩阵。
  11. 根据权利要求7-10中任一项所述的方法，其特征在于，所述第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值包括：
    所述多个STA分别发送的多个第一组训练序列和信道信息矩阵用于确定第一信息矩阵；
    所述多个STA分别发送的多个第二组训练序列和信道信息矩阵用于确定第二信息矩阵；
    所述第一信息矩阵和所述第二信息矩阵用于求解所述多个STA分别与所述AP之间的频偏值。
  12. 根据权利要求11所述的方法，其特征在于，所述AP基于所述多个STA分别与所述AP之间的频偏值，进行信道估计包括：
    所述AP基于所述多个STA分别与所述AP之间的频偏值修正所述P矩阵，得到修正后的P矩阵；
    所述AP基于所述第一信息矩阵和/或所述第二信息矩阵，以及所述修正后的P矩阵确定所述信道信息矩阵。
  13. 根据权利要求7-12中任一项所述的方法，其特征在于，所述第一组训练序列占用所述帧中的Q个第一位置，
    所述第二组训练序列占用所述帧中的Q个第二位置，
    其中，所述Q个第一位置和所述Q个第二位置依次先后排列；或者，所述Q个第一位置和Q个第二位置等间隔交叉排列，所述Q为与M满足预设的对应关系的整数，所述M为所述多个STA的天线总数。
  14. 根据权利要求7-13中任一项所述的方法，其特征在于，所述第一组训练序列中包括一个或多个第一训练序列，所述第二组训练序列中包括一个或多个第二训练序列。
  15. 一种站点，其特征在于，包括：
    处理单元，用于生成帧，所述帧中包括第一组训练序列和第二组训练序列，所述第一组训练序列和第二组训练序列用于求解所述站点STA与所述AP之间频偏值，所述频偏值用于信道估计；
    发送单元，用于向所述AP发送所述帧。
  16. 根据权利要求15所述的站点，其特征在于，在所述处理单元生成所述帧之前，所述站点还包括：
    接收单元，用于接收来自所述AP的指示信息，所述指示信息用于指示所述STA生成 所述帧。
  17. 根据权利要求16所述的站点，其特征在于，所述指示信息还用于指示所述处理单元生成所述帧的过程是否使用预设相位识别矩阵，和/或，
    所述指示信息还用于指示所述第一组训练序列和所述第二组训练序列在所述帧中的排列方式。
  18. 根据权利要求15-17中任一项所述的站点，其特征在于，所述第一组训练序列由预设训练序列乘以P矩阵中对应于所述STA的元素得到，
    所述第二组训练序列由预设训练序列乘以所述P矩阵或P1矩阵中对应于所述STA的元素得到，
    其中，所述P1矩阵为基于预设相位识别矩阵确定的矩阵，所述P矩阵为所述AP和所述多个STA已知的用于信道估计的矩阵。
  19. 根据权利要求15-18中任一项所述的站点，其特征在于，所述第一组训练序列占用所述帧中的Q个第一位置，
    所述第二组训练序列占用所述帧中的Q个第二位置，
    其中，所述Q个第一位置和所述Q个第二位置依次先后排列；或者，所述Q个第一位置和Q个第二位置等间隔交叉排列，所述Q为与M满足预设的对应关系的整数，所述M为所述多个STA的天线总数。
  20. 根据权利要求15-19中任一项所述的站点，其特征在于，所述第一组训练序列中包括一个或多个第一训练序列，所述第二组训练序列中包括一个或多个第二训练序列。
  21. 一种接入点，其特征在于，包括：
    接收单元，用于接收多个STA分别发送的帧，所述帧中包括第一组训练序列和第二组训练序列，所述第一组训练序列和第二组训练序列用于求解STA与所述接入点AP之间频偏值；
    处理单元，用于基于所述多个STA分别与所述AP之间的频偏值，进行信道估计。
  22. 根据权利要求21所述的接入点，其特征在于，所述接入点还包括：
    发送单元，用于向所述STA发送指示信息，所述指示信息用于指示所述STA生成所述帧。
  23. 根据权利要求22所述的接入点，其特征在于，所述指示信息还用于指示所述STA生成所述帧的过程是否使用预设相位识别矩阵，和/或，
    所述指示信息还用于指示所述第一组训练序列和所述第二组训练序列在所述帧中的排列方式。
  24. 根据权利要求21-23中任一项所述的接入点，其特征在于，所述第一组训练序列由预设训练序列乘以P矩阵中对应于所述STA的元素得到，
    所述第二组训练序列由预设训练序列乘以P矩阵或P1矩阵中对应于所述STA的元素得到，
    其中，所述P1矩阵为基于预设相位识别矩阵确定的矩阵，所述P矩阵为所述AP和所述M个STA已知的用于信道估计的矩阵。
  25. 根据权利要求21-24中任一项所述的接入点，其特征在于，所述第一组训练序列和第二组训练序列用于求解STA与接入点AP之间频偏值包括：
    所述多个STA分别发送的多个第一组训练序列和信道信息矩阵用于确定第一信息矩阵；
    所述多个STA分别发送的多个第二组训练序列和信道信息矩阵用于确定第二信息矩阵；
    所述第一信息矩阵和所述第二信息矩阵用于求解所述多个STA分别与所述AP之间的频偏值。
  26. 根据权利要求25所述的接入点，其特征在于，所述处理单元基于所述多个STA分别与所述AP之间的频偏值，进行信道估计包括：
    所述处理单元基于所述多个STA分别与所述AP之间的频偏值修正所述P矩阵，得到修正后的P矩阵；
    所述处理单元基于所述第一信息矩阵和/或所述第二信息矩阵，以及所述修正后的P矩阵确定所述信道信息矩阵。
  27. 根据权利要求21-26中任一项所述的接入点，其特征在于，所述第一组训练序列占用所述帧中的Q个第一位置，
    所述第二组训练序列占用所述帧中的Q个第二位置，
    其中，所述Q个第一位置和所述Q个第二位置依次先后排列；或者，所述Q个第一位置和Q个第二位置等间隔交叉排列，所述Q为与M满足预设的对应关系的整数，所述M为所述多个STA的天线总数。
  28. 根据权利要求21-27中任一项所述的接入点，其特征在于，所述第一组训练序列中包括一个或多个第一训练序列，所述第二组训练序列中包括一个或多个第二训练序列。
  29. 一种通信装置，其特征在于，所述装置用于执行权利要求1至14中任一项所述的方法。
  30. 一种通信装置，其特征在于，包括：处理器，
    所述处理器与存储器耦合，用于从所述存储器中调用并运行计算机程序，以执行权利要求1-14中任一项所述的方法。
  31. 一种通信装置，其特征在于，包括：处理器，存储器，
    所述存储器用于存储计算机程序，所述处理器用于从所述存储器中调用并运行所述计算机程序，以执行权利要求1-14中任一项所述的方法。
  32. 一种计算机可读存储介质，其特征在于，所述计算机可读介质存储用于设备执行的计算机程序，所述计算机程序包括用于执行如权利要求1-14中任一项所述的方法的程序指令。
  33. 一种芯片，其特征在于，所述芯片包括处理器与数据接口，所述处理器通过所述数据接口读取存储器上存储的程序指令，以执行如权利要求1-14中任一项所述的方法。
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