WO2016065515A1 - Procédé et appareil de transmission d'informations - Google Patents

Procédé et appareil de transmission d'informations Download PDF

Info

Publication number
WO2016065515A1
WO2016065515A1 PCT/CN2014/089589 CN2014089589W WO2016065515A1 WO 2016065515 A1 WO2016065515 A1 WO 2016065515A1 CN 2014089589 W CN2014089589 W CN 2014089589W WO 2016065515 A1 WO2016065515 A1 WO 2016065515A1
Authority
WO
WIPO (PCT)
Prior art keywords
ltf
sequence
index
subcarrier
data stream
Prior art date
Application number
PCT/CN2014/089589
Other languages
English (en)
Chinese (zh)
Inventor
卢伟山
林伟
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2014/089589 priority Critical patent/WO2016065515A1/fr
Publication of WO2016065515A1 publication Critical patent/WO2016065515A1/fr

Links

Images

Classifications

    • 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

Definitions

  • the present invention relates to the field of mobile communications technologies, and in particular, to a method and an apparatus for transmitting information.
  • the 802.11ac standard introduces downlink Multiple Input Multiple Output (MIMO) technology.
  • MIMO Multi-user-Multiple Input Multiple Output
  • MIMO Multi-user-Multiple Input Multiple Output
  • the transmitter can simultaneously be connected to multiple receivers or users.
  • the difficulty in transmitting data is that the transmitting end needs to obtain the channel information of each user in real time, and the overhead is relatively large.
  • the user receiving process does not need to consider other users, for example, the number of antennas of other users, data.
  • the future wifi system or wifi standard will consider the uplink MU-MIMO technology, and the uplink MU-MIMO technology is also to solve the problem of the asymmetric number of link antennas, contrary to the downlink MU-MIMO technology. It is a multi-to-one transmission technology based on spatial multiplexing. With the uplink MU-MIMO technology, multiple users can simultaneously transmit data to a base station or an access point (AP), thereby improving the data rate of uplink transmission. The uplink MU-MIMO technology does not require the AP to obtain instant user channel information in advance, and the overhead is relatively small.
  • the uplink MU-MIMO technology an important factor that restricts the use of the uplink MU-MIMO technology is that each user needs to be synchronized with the frequency guarantee in time.
  • OFDM Orthogonal Frequency Division Multiple Access
  • the system bandwidth can be divided into several subcarriers.
  • frequency synchronization is especially important, which can ensure that the subcarriers are orthogonal, so that they There is no mutual interference.
  • the base station if the frequency between users is not synchronized and the user and the base station frequency are not synchronized, the base station not only interferes with other subcarrier data but also interferes with the current subcarrier data of the current user. Interfered with the data of each subcarrier of other users, if the estimation and By compensating for the frequency offset between each user and the base station, the bit error rate of the system is greatly improved.
  • the base station is equipped with P antennas, Q ⁇ 2 users communicate with the base station at the same time, without loss of generality, each user is set to install an antenna, and each data stream is transmitted to the base station, so P ⁇ Q needs to be guaranteed.
  • the system bandwidth is divided into N subcarriers, and the frequency deviation between each user and the base station is ⁇ q , where q is the index of the user; the nth subcarrier between the qth user and the base station p antenna is set.
  • the channel transfer matrix between Therefore, the received signal of the base station after the IFFT transform of the kth OFDM symbol can be modeled as:
  • N B N+N GI
  • N GI represents the length of the Guard Interval (GI)
  • N ST represents the number of subcarriers loaded with data N ST ⁇ N;
  • a q (k, n) represents a signal transmitted by the qth user in the kth OFDM symbol and the nth subcarrier
  • z p (k, n) represents the noise of the p-th antenna of the base station at the k-th OFDM symbol and the n-th sub-carrier;
  • the base station will phase rotate when decoding the current subcarrier data of the current user. And have a corresponding amplitude drop
  • ICI interference can be modeled as noise. When the subcarrier is large enough or the signal to interference ratio is large enough, the impact of ICI interference is negligible. . Therefore, at the AP end, the frequency deviation ⁇ q of each user needs to be estimated to compensate the phase deflection of the user.
  • the AP needs to estimate the channel information by means of the training sequence.
  • the probability that the channel information estimation is erroneous increases, and the probability that an error occurs in the decoded data later increases.
  • How to improve channel estimation and how to estimate the frequency offset of each user is a very critical issue. It is related to whether the data packet can be decoded correctly, which will seriously affect whether the uplink MU-MIMO technology can improve the throughput of the system.
  • channel estimation relies on the Long Training Field (LTF) portion.
  • LTF Long Training Field
  • S tot ⁇ 1 and S tot is odd, the transmitting end sends S tot +1 LTFs, and the sequence of each LTF is the same.
  • the S tot LTFs need to be multiplied by a P matrix (orthogonal matrix), that is, each element in the i-th LTF of the j-th data stream needs to be multiplied.
  • P matrix orthogonal matrix
  • the transmitting end continuously transmits four LTFs, which are LTF1, LTF2, LTF3, LTF4, and multiplied by the corresponding P matrix.
  • the receiving signal of the receiving end on the nth subcarrier can be expressed as:
  • LTF n represents the nth subcarrier symbol of the LTF sequence
  • [h p,q ] n represents a channel response between the pth receiving antenna and the qth receiving antenna on the nth subcarrier;
  • Y k,n represents the reception vector of the nth subcarrier of the kth OFDM symbol at the receiving end
  • Z k,n represents the noise vector of the nth subcarrier of the kth OFDM symbol at the receiving end
  • Channel estimation can use the LS method, ie
  • the receiver can estimate the channel [h p,q ] n .
  • the influence of noise will become smaller and smaller, and the channel estimation value will be correspondingly higher. The more precise it is.
  • the prior art has pointed out that carrier misalignment between users and between the user and the base station produces phase rotation of the signal, thereby disrupting the orthogonality of the P matrix.
  • the AP is equipped with 4 antennas, the user installs an antenna, and 4 users simultaneously send data to the AP.
  • the four users can be equivalent to one user, and the user has 4 antennas, and the 4 antennas
  • the transmitted data stream is independently coded.
  • the P matrix of equation (3) is affected by the frequency offset, so that the orthogonality is “destroyed”, considering the frequency offset.
  • the latter P matrix can be expressed as:
  • E is a unit matrix
  • the matrix after multiplication is not a unit matrix
  • the matrix will be included in the channel matrix [h p,q ] n , thereby affecting the phase and amplitude of the channel estimation, along with the phase of each user.
  • the performance of the channel estimation is worse, and the effect of phase rotation does not improve as the signal-to-noise ratio improves.
  • the embodiment of the invention provides a method and a device for transmitting information, which are used to solve the problem that the orthogonality of the P matrix is affected by the frequency offset of the station carrier, thereby affecting the correctness of the channel estimation.
  • an information sending method is provided, which is applied to a wireless local area network that uses an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams; the method includes:
  • the station generates a plurality of long training sequence symbols LTF, and any data stream sent by the station is allocated R subcarriers on the plurality of LTFs, and the R subcarriers are used to carry a channel estimation sequence, in the multiple
  • the LTF includes a first LTF and a second LTF, wherein for any of the data streams:
  • An index of an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF, and an ith subcarrier of a channel estimation sequence for carrying the data stream in the second LTF A specific first difference is satisfied between the indices, where i is a positive integer less than or equal to F, F a total number of subcarriers of the channel estimation sequence used to carry the data stream in the first LTF or the second LTF; and the first LTF or the second LTF is used to carry a channel estimate of the data stream
  • the second difference between the indices of adjacent subcarriers of the sequence is twice the first difference;
  • the station transmits the plurality of long training sequences LTF.
  • the method further includes:
  • N g ceil(N ST /R), where the ceil operation is rounded up, and N ST is the total number of subcarriers of the uplink transmission data symbol of the station.
  • the method further includes:
  • the F is greater than or equal to floor(R/I), where the floor operation is rounded down, I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil(S tot /N g ), S tot is the number of the plurality of data streams; and in any of the LTFs, the subcarriers allocated to different data streams for carrying the channel estimation sequence are different.
  • the method before the sending the multiple LTFs, the method further includes:
  • the station receives LTF indication information sent by the access point AP, where the LTF indication information is used to indicate a subcarrier index for carrying a channel estimation sequence in all LTFs sent in any one of the data streams.
  • the present invention provides an information processing method, which is applied to a wireless local area network that uses an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams; the method includes:
  • the AP receives a plurality of long training sequence symbols LTF; for any data stream of any of the stations, the plurality of LTFs include a first LTF and a second LTF, wherein the first LTF and the second LTF need to meet
  • LTF long training sequence symbols
  • An index of an i th subcarrier of a channel estimation sequence for carrying the data stream in the first LTF, and an i th channel of a channel estimation sequence for carrying the data stream in the second LTF A specific first difference is satisfied between the indices of the subcarriers, where i is a positive integer less than or equal to F, and F is a subcarrier of the channel estimation sequence used to carry the data stream in the first LTF or the second LTF
  • the index of the subcarrier that satisfies the first difference relationship in the first LTF is a first subcarrier index sequence
  • the index of the subcarrier that satisfies the first difference relationship in the second LTF is the second Subcarrier index sequence;
  • the first LTF or the second LTF needs to satisfy a relationship that a second difference between the indices of adjacent subcarriers of the sequence of the first LTF or the second LTF for carrying the data stream for channel estimation is Describe the first difference of 2 times;
  • the determining, by the plurality of long training sequence symbols LTF, the frequency offset value between the any one of the stations and the AP includes:
  • the method further includes:
  • N g ceil(N ST /R), where the ceil operation is rounded up, and N ST is the total number of subcarriers of the uplink data transmission symbol of any one of the stations;
  • the F is greater than or equal to floor(R/I), where the floor operation is rounded down, I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil(S tot /N g ), S tot is the number of the plurality of data streams; and in any of the LTFs, the subcarriers allocated to different data streams for carrying the channel estimation sequence are different.
  • the first channel information and the second channel information are separately interpolated to obtain the first
  • the three channel information and the fourth channel information further include:
  • the distance between the first index and the second index corresponding to the inserted channel information is less than or equal to floor(N g /2)+1, where the second index is multiple of the R subcarriers One of the indexes.
  • the present invention provides a station, which is applied to a wireless local area network that uses an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams; the station includes:
  • a symbol generating module configured to generate a plurality of long training sequence symbols LTF, where any data stream sent by the station is allocated R subcarriers on the multiple LTFs, where the R subcarriers are used to carry a channel estimation sequence, Include, in the plurality of LTFs, a first LTF and a second LTF, wherein for any of the data flows: an index of an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF And satisfying, between the index of the ith subcarrier of the channel estimation sequence for carrying the data stream in the second LTF, where i is a positive integer less than or equal to F, where F is a total number of subcarriers used to carry a channel estimation sequence of the data stream in a first LTF or a second LTF; and the first LTF or second LTF is used to carry a phase of a channel estimation sequence of the data stream
  • the second difference between the indexes of the adjacent subcarriers is twice the first difference;
  • a sending module configured to send the plurality of long training sequences LTF.
  • the symbol generating module is further configured to:
  • the value of F is determined by the formula floor(R/I), wherein the F is greater than or equal to floor(R/I), the floor operation is rounded down, and I is the total number of LTFs sent in any of the data streams. Number, and I satisfies I ⁇ ceil(S tot /N g ), S tot is the number of the plurality of data streams; and in any of the LTFs, the different data streams are allocated for carrying the channel estimation sequence The carriers are not the same.
  • the site further includes:
  • a receiving module configured to receive LTF indication information sent by an access point AP, where the LTF indication information is used to indicate, in a total of all LTFs sent in any one of the data streams, the sub-carrier for the channel estimation sequence Carrier index.
  • the present invention provides an access, which is applied to a wireless local area network that uses an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams; the access point includes:
  • a receiving module configured to receive, by the AP, a plurality of long training sequence symbols LTF; for any data stream of any of the stations, the plurality of LTFs include a first LTF and a second LTF, wherein the first LTF and the second The following relationships need to be met between LTFs:
  • An index of an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF, and an ith subcarrier of a channel estimation sequence for carrying the data stream in the second LTF A specific first difference is satisfied between the indices, where i is a positive integer less than or equal to F, and F is a total of subcarriers of the channel estimation sequence for carrying the data stream in the first LTF or the second LTF
  • the index of the subcarrier that satisfies the first difference relationship in the first LTF is a first subcarrier index sequence
  • the index of the subcarrier that satisfies the first difference relationship in the second LTF is the second subcarrier Index sequence
  • the first LTF or the second LTF needs to satisfy a relationship that a second difference between the indices of adjacent subcarriers of the sequence of the first LTF or the second LTF for carrying the data stream for channel estimation is Describe the first difference of 2 times;
  • an offset determining module configured to obtain, according to the plurality of long training sequence symbols LTF, a frequency offset value between the any one of the stations and the AP.
  • the offset determining module includes:
  • a channel information estimating unit configured to: after receiving the plurality of long training sequence symbols LTF, estimate that any data stream sent by any station is allocated a channel for carrying R channel subcarriers of the channel estimation sequence on the multiple LTFs information;
  • An acquiring unit configured to acquire a first subcarrier index sequence from the first LTF, and obtain a second subcarrier index sequence from the second LTF;
  • An interpolating unit configured to determine, according to the first subcarrier index sequence and the second subcarrier index sequence, first channel information and second channel information corresponding to the data stream, respectively, to the first channel information and Performing an interpolation operation on the two channels of information to obtain third channel information and fourth channel information;
  • an offset determining unit configured to obtain, according to the third channel information and the fourth channel information, a frequency offset value between the any one of the stations and the AP.
  • the F is greater than or equal to floor(R/I), where the floor operation is rounded down, I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil(S tot /N g And S tot is the number of the plurality of data streams; and in any of the LTFs, the subcarriers allocated to different data streams for carrying the channel estimation sequence are different.
  • the interpolating unit is further configured to determine a location of any channel information inserted by using the formula floor(N g /2)+1
  • the distance between the first index and the second index corresponding to any channel information inserted is less than or equal to floor(N g /2)+1, and the second index is corresponding to the R subcarriers.
  • the indexes is a value that is less than or equal to floor(N g /2)+1.
  • the station sends the LTF according to a certain rule, so that the AP separately estimates part of the channel information of a data stream in the received multiple LTFs, and obtains the data stream according to the partial channel information.
  • the frequency offset value between the station and the AP so that the phase information corresponding to the channel information of different LTFs is compensated accordingly, so that the influence of phase rotation on the channel estimation can be avoided. Avoiding the orthogonality of the P matrix is affected by the carrier carrier frequency offset, which affects the correctness of the channel estimation.
  • FIG. 1 is a schematic flowchart diagram of a method for sending information according to Embodiment 1 of the present invention
  • FIG. 2 is a schematic diagram of two LTFs in an embodiment of the present invention.
  • FIG. 3 is a schematic flowchart diagram of an information processing method according to Embodiment 2 of the present invention.
  • 3a is a schematic flowchart of a frequency offset estimation method according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of an index allocated by four data streams in four LTFs according to an embodiment of the present invention
  • FIG. 5 is a schematic diagram of an index allocated by eight data streams in four LTFs according to an embodiment of the present invention
  • FIG. 6 is a schematic structural diagram of a station according to an embodiment of the present disclosure.
  • FIG. 7 is a schematic structural diagram of an access point according to an embodiment of the present disclosure.
  • Figure 9 is a constellation point diagram when data is decoded after channel estimation using the method of the present invention.
  • the embodiment of the present invention provides an information sending method, which should be In a wireless local area network using uplink MU-MIMO technology, the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams; the method includes:
  • Step 101 The station generates a plurality of long training sequence symbols LTF, and any data stream sent by the station is allocated R subcarriers on the multiple LTFs, where the R subcarriers are used to carry a channel estimation sequence.
  • the first LTF and the second LTF are included in the plurality of LTFs, wherein, for any of the data streams:
  • An index of an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF, and an ith subcarrier of a channel estimation sequence for carrying the data stream in the second LTF The first difference is satisfied between the indexes, where i is a positive integer less than or equal to F, and F is the total number of subcarriers in the first LTF or the second LTF for carrying the channel estimation sequence of the data stream; And, the second difference between the indexes of the adjacent subcarriers used by the first LTF or the second LTF to carry the channel estimation sequence of the data stream is twice the first difference;
  • the F is greater than or equal to floor(R/I), wherein the floor operation is rounded down, and I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil (S tot / N g) , S tot the number of the plurality of data streams; and any one of the LTF allocated to different data streams for carrying the subcarrier channel estimation sequence not identical.
  • Step 102 The station sends the multiple long training sequences LTF.
  • the first column and the second column in the figure respectively represent the first LTF and the second LTF; each row of each column is used to represent a subcarrier, the square The sequence number from top to bottom is used to indicate the index of the subcarrier, and the number appearing in each column is used to represent the data stream.
  • Figure 2 shows four data streams, called data streams 1, 2, 3 or 4.
  • the index assigned by the data stream 1 in the first LTF is [1, 3, 5, 7...] (ie, the portion of the first column of FIG. 2 with the cell number 1); that is, in the first LTF.
  • the index of the first subcarrier used to carry the channel estimation sequence of data stream 1 is 1; the index of the second subcarrier is 3...
  • the index assigned by the data stream 1 in the second LTF is [2, 4, 6, 8, ...] (ie, the portion of the second column of FIG. 2 with the cell number 1), that is, the data used to carry the data in the first LTF.
  • Channel 1 channel estimation sequence The index of the first subcarrier of the column is 2; the index of the second subcarrier is 4...
  • the total number E.g:
  • the second difference between the indexes of the adjacent subcarriers used by the first LTF or the second LTF for carrying the channel estimation sequence of the data stream is the A specific difference of 2 times can be:
  • the index assigned by data stream 1 in the first LTF is [1, 3, 5, 7...] (ie, the portion of the first column of FIG. 2 with the cell number 1); that is, the first LTF is used to carry data.
  • the index of the first subcarrier of the channel estimation sequence of stream 1 is 1; the index of the second subcarrier is 3...
  • the AP sends a message to instruct the station to send the required LTF, so in the embodiment of the present invention, the method provided by the embodiment of the present invention further includes:
  • the station receives LTF indication information sent by the access point AP, where the LTF indication information is used to indicate that all of the LTFs sent in the any data stream are used to carry the channel estimation sequence.
  • the subcarrier index of the column is used to indicate that all of the LTFs sent in the any data stream are used to carry the channel estimation sequence.
  • the manner in which the LTF indication message is sent by the AP may be multiple.
  • the following two optional implementation manners are provided:
  • the LTF indication information may include site identifier information, site data stream index information, and total number of data streams.
  • the site identifier information is used to indicate which stations transmit data upstream
  • the site data stream index information is used to identify or distinguish the uplink transmission of the station.
  • the total number of data streams is used to indicate how many long training sequence symbols LTF need to be sent by the uplink transmission station;
  • the station receives the LTF indication information, reads the site identification information in the LTF indication information, and matches the own site identification information. If the matching is successful, the site data stream index information and the total number of data streams in the LTF indication information are searched.
  • the buffer obtains a subcarrier index for carrying the channel estimation sequence in the entire LTF in the cache, and the buffer stores the subcarrier index case of each data stream as shown in FIG. 4 or FIG. 5 for the channel estimation sequence.
  • LTF indication information may include site identification information, and subcarrier index allocation information used by the station to carry the channel estimation sequence in all LTFs.
  • the station receives the LTF indication information, reads the site identification information in the LTF indication information, and matches the own site identification information. If the matching succeeds, the corresponding data flow sent by the site is obtained from the LTF indication information in all LTFs.
  • an embodiment of the present invention provides an information processing method, which is applied to a wireless local area network that uses an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams;
  • Methods include:
  • Step 301 The AP receives a plurality of long training sequence symbols LTF.
  • the multiple LTFs include a first LTF and a second LTF, where the first LTF and the second LTF are The following relationships need to be met:
  • An index of an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF, and an ith subcarrier of a channel estimation sequence for carrying the data stream in the second LTF A specific first difference is satisfied between the indices, where i is a positive integer less than or equal to F, F a total number of subcarriers of the channel estimation sequence used to carry the data stream in the first LTF or the second LTF; and an index of the subcarrier that satisfies the first difference relationship in the first LTF is first a subcarrier index sequence, where the index of the subcarrier that satisfies the first difference relationship in the second LTF is a second subcarrier index sequence;
  • the first LTF or the second LTF needs to satisfy a relationship that a second difference between the indices of adjacent subcarriers of the sequence of the first LTF or the second LTF for carrying the data stream for channel estimation is Describe the first difference of 2 times;
  • Step 302 Obtain a frequency offset value between the any one of the stations and the AP according to the plurality of long training sequence symbols LTF.
  • the method for obtaining the first difference value and the F value includes multiple types, and the specific implementation manner may be:
  • N g ceil(N ST /R), where the ceil operation is rounded up, and N ST is the total number of subcarriers of the uplink data transmission symbol of any one of the stations;
  • the F is greater than or equal to floor(R/I), where the floor operation is rounded down, I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil(S tot /N g ), S tot is the number of the plurality of data streams; and in any of the LTFs, the subcarriers allocated to different data streams for carrying the channel estimation sequence are different.
  • the AP sends a message to instruct the station to send the required LTF, so in the embodiment of the present invention, The AP further sends a specific indication message to the site, thereby instructing the site to send the LTF.
  • the method provided by the embodiment of the present invention further includes:
  • the LTF indication information sent by the access point AP is sent to the station, and the LTF indication information is used to indicate a subcarrier index for carrying a channel estimation sequence in all LTFs sent by the station.
  • the manner in which the LTF indication message is sent by the AP may be multiple.
  • the following two optional implementation manners are provided:
  • the first type: the LTF indication information may include site identification information, site data flow index information to And the total number of data streams, the site identifier information is used to indicate which stations transmit data in the uplink, and the site data stream index information is used to identify or distinguish each data stream in the uplink transmission of the station, and the total number of data streams is used to indicate that the uplink transmission site needs to be sent. How many long training sequence symbols LTF;
  • the site After receiving the LTF indication information, the site reads the site identification information in the LTF indication information and matches the own site identification information. If the matching succeeds, according to the site data flow index information and the total number of data flows in the LTF indication information, Obtaining, in the cache, a subcarrier index for acquiring a channel estimation sequence in the entire LTF in the cache, where the buffer stores the subcarrier index of each channel for the channel estimation sequence as shown in FIG. 4 or FIG. .
  • LTF indication information may include site identification information, and subcarrier index allocation information used by the station to carry the channel estimation sequence in all LTFs.
  • the site After receiving the LTF indication information, the site reads the site identification information in the LTF indication information and matches the own site identification information. If the matching succeeds, the corresponding data flow sent by the site is obtained from the LTF indication information in all LTFs.
  • the subcarrier index used to carry the channel estimation sequence used to carry the channel estimation sequence.
  • a specific implementation manner of obtaining a frequency offset value between the any one station and the AP according to the plurality of long training sequence symbols LTF is obtained.
  • Step 3a01 After receiving the plurality of long training sequence symbols LTF, estimating that any data stream sent by any station is allocated channel information for R subcarriers carrying the channel estimation sequence on the multiple LTFs;
  • the Q stations and the access point AP simultaneously transmit S tot data streams, and the channel information of the R subcarriers is required for each data stream to estimate the channel information of the N ST subcarriers.
  • the WLAN system includes N subcarriers, including N ST subcarriers for uplink transmission of data symbols
  • the AP is installed with P antennas, and each antenna is connected to one radio frequency link, including Q ⁇ 2 stations communicating with the AP, where Q In the stations, the qth station sends S q (S q ⁇ 1) data streams to the AP, and the total number of data streams is satisfied.
  • Step 3a02 Acquire a first subcarrier index sequence from the first LTF, and obtain a second subcarrier index sequence from the second LTF.
  • the first subcarrier index sequence is an index of a subcarrier used to carry a channel estimation sequence of the first data stream in the first LTF;
  • the second subcarrier index sequence is a channel used to carry the first data stream in the second LTF Estimate the index of the subcarriers of the sequence.
  • the first subcarrier index sequence may be a part of a data stream in the first LTF or all subcarrier indexes, and the intercepting manner and the first subcarrier of the same second subcarrier index sequence.
  • the index sequences are the same.
  • the number of subcarrier indices included in the first subcarrier index sequence and the second subcarrier index sequence are the same.
  • each data stream needs channel information of R subcarriers.
  • the first difference N g 1, and the data stream 1 (marked in FIG. 2) No. 1)
  • the index assigned in the first LTF is [1, 3, 5, 7...]; the index assigned in the second LTF is [2, 4, 6, 8, ...], then
  • the first subcarrier index sequence may be [1, 3, 5, 7], and the corresponding second subcarrier index sequence may be [2, 4, 6, 8], then the first subcarrier index in this example
  • Step 3a03 determining, according to the first subcarrier index sequence and the second subcarrier index sequence, first channel information and second channel information corresponding to the data stream, respectively, to the first channel information and the second channel
  • the information is interpolated to obtain third channel information and fourth channel information;
  • the method when the first channel information and the second channel information are respectively subjected to the interpolation operation to obtain the third channel information and the fourth channel information, the method further includes:
  • the distance between the first index and the second index corresponding to the inserted channel information is less than or equal to floor(N g /2)+1, where the second index is multiple of the R subcarriers One of the indexes.
  • the interpolated position is 2, 4, 6.
  • Step 3a04 Obtain a frequency offset value between the any one of the stations and the AP according to the third channel information and the fourth channel information.
  • the interpolated channel estimation information subcarrier index of the first subcarrier sequence index 1, 3, 5 is 1, 2, 3, 4, 5, 6, and the second subcarrier sequence index 2, 4, 6 is interpolated.
  • the method further includes:
  • the specific implementation method of the update may be:
  • the subcarrier index sequence corresponding to the subcarrier used to carry the channel estimation sequence is
  • ⁇ i,q is the total number of subcarriers used by the data stream to carry the channel estimation sequence in the ith LTF symbol
  • ⁇ 1,i,q is the data stream used for the bearer channel estimation in the ith LTF symbol
  • the first subcarrier index corresponding to the subcarrier of the sequence The data stream is used in the i-th LTF symbol for the ⁇ i, q sub-carrier index corresponding to the sub-carrier carrying the channel estimation sequence;
  • n ⁇ ⁇ i, q , N B N + N GI
  • N represents a Fourier transform Or the number of points of the inverse Fourier transform
  • N GI represents the length of the guard interval
  • h q,i,n is the channel information of the data stream estimated by the receiving antennas of the AP at the ith LTF symbol and the nth subcarrier
  • h q,i,n [h 1,q,i,n h 2,q,i,n ...
  • the parameter P is the number of receiving antennas of the base station
  • h p,q , i, n is channel information of the i-th LTF symbol and the n-th sub-carrier estimated by the p-th receiving antenna of the AP.
  • the AP respectively estimates partial channel information of a data stream in the received plurality of LTFs, and obtains a frequency offset value between the station transmitting the data stream and the AP according to the partial channel information. Therefore, corresponding phase rotation compensation is performed on channel information corresponding to different LTFs, so that the influence of phase rotation on channel estimation can be avoided. Avoiding the orthogonality of the P matrix is affected by the carrier carrier frequency offset, which affects the correctness of the channel estimation.
  • the WLAN system includes N subcarriers, including N ST subcarriers for uplink transmission of data symbols, and the AP is equipped with P antennas, each antenna is connected to one radio frequency link, including Q ⁇ 2 stations communicating with the AP, where Q In the stations, the qth station sends S q (S q ⁇ 1) data streams to the AP, and the total number of data streams is satisfied.
  • FIG. 4 is a subcarrier allocation situation of four data streams in four LTFs, where four vertical columns represent a first LTF, a second LTF, a third LTF, and a fourth LTF; each row in each column is used for Indicates a subcarrier whose sequence number from top to bottom is used to indicate the index of the subcarrier, and the number appearing in each column of cells is used to represent the data stream.
  • data streams 1, 2, 3 or 4 i.e., in Figures 1, 2, 3, 4 of each square of Figure 4.
  • the label 1 in the square of the second row of the first column in FIG. 4 indicates that the first subcarrier in the first LTF is allocated to the data stream 1, and the subcarrier cable Quoted as 1, the second subcarrier index is 3.
  • a total of 56 subcarriers are loaded with data, and in each LTF, the 56 subcarriers are equally allocated to the 4 data streams, and each data stream is obtained with 14 subcarriers.
  • the index of the subcarrier allocated in the first LTF in the first LTF is incremented by one compared to the subcarrier index allocated by the second LTF, for example, in the first LTF.
  • the first, third, fifth, seventh subcarriers are allocated to the data stream 1, and in the second LTF, the second, fourth, sixth, eighth, ... subcarriers are allocated to the data stream 1.
  • the AP estimates the channel information of the subcarriers allocated by the data stream 1 in the first LTF, that is, h 1,1 , h 1,3 , h 1,5 ,...h 1,27 ; h 1,1 ,h 1,3 ,h 1,5 ,...h 1,27 perform interpolation to obtain h 1,2 , h 1,4 , h 1,6 ,...h 1,28 channel information, and finally get complete The channel information of the 28 subcarriers, namely h 1,1 , h 1,2 , h 1,3 ,...h 1,28 .
  • the AP estimates the channel information of the subcarriers allocated by the data stream 1 based on the second LTF, and performs an interpolation operation based on h 2 , 2 , h 2 , 4 , h 2 , 6 , ... h 2 , 28 to obtain h 2 , 1, h 2,3, h 2,5 , ... h 2,27 information channel, the last 28 subcarriers to obtain complete information of the channel, i.e., h 2,1, h 2,2, h 2,3 , ... h 2,28 .
  • the AP can compensate the channel information, and the AP compensates the channel information of the data stream estimated in the second LTF, that is, Similarly, in the third LTF, the data stream 1 is allocated with 29th, 31..., 55 subcarriers, and the AP can perform phase rotation compensation on the channel information of the data stream 1 estimated in the third LTF, that is, Finally, the AP may perform phase rotation compensation on the channel information of the data stream 1 estimated in the fourth LFT, that is,
  • the AP estimates the partial channel information of the data stream 1 in the four LTFs and performs corresponding phase rotation compensation, which effectively improves the channel estimation accuracy, thereby reducing the bit error rate of the subsequent data.
  • the same method can be applied to the data stream 2, the data stream 3, and the data stream 4, so that the AP respectively performs corresponding phase rotation compensation on the channel information of the four data streams.
  • the 20M bandwidth is divided into 256 subcarriers, and the interval of each subcarrier is 78.125 KHz.
  • the AP communicates with the station using MIMO technology, if the AP or the station needs to transmit S tot data streams, the AP or the station needs to send.
  • One LTF symbol is used for channel estimation.
  • the AP or the station For each data stream, the AP or the station only needs the channel information of the R subcarriers, and the channel information of the N ST subcarriers can be estimated by the interpolation method, and each data stream is in the estimated R subcarrier channel information.
  • the first difference Ng is 2, that is, the subcarrier index of a certain data stream is known after the receiving end receives the LTF.
  • the channel information of 1, 3, 5, 7... the channel information of the subcarrier index is 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12... can be estimated by the interpolation method. That is, a channel value of one subcarrier, that is, a channel value of subcarrier 2, needs to be interpolated between subcarrier 1 and subcarrier 3 of two adjacent channel estimations.
  • the interpolation interval is N g
  • the number of LTFs to be transmitted is I ⁇ ceil (S tot / N g )
  • the LTF also occupies 30 subcarriers in each LTF.
  • the subcarrier index allocation in each LTF in each LTF is shown in Figure 5:
  • the four vertical columns in FIG. 5 respectively represent the first LTF, the second LTF, the third LTF, and the fourth LTF; each row of each column is used to represent a subcarrier, and the serial number of the square from top to bottom is used to indicate The index of the subcarrier, the number appearing in each column of the square is used to represent the data stream.
  • Figure 5 shows eight data streams, referred to as data streams 1, 2, 3, ... 8 (i.e., in Figures 5, 2, 3, ... 8 of each square).
  • the label 1 in the square of the sixth row of the first column in FIG. 5 indicates that the fifth subcarrier in the first LTF is allocated to the data stream 1, and the subcarrier index is 5.
  • Data stream 1 occupies the subcarriers indexed as 1, 5, 10, 15, ..., 113, 117 in the first LTF; the index is 3, 7, 11, 115, 119 in the second LTF.
  • the AP estimates the channel information of the subcarriers allocated by data stream 1 in the first LTF, that is, h 1,1 , h 1,5 , h 1,10 ,...h 1,113 , h 1,117 ; and according to general or traditional The interpolation algorithm obtains channel information of 119 subcarriers, namely h 1,1 , h 1,2 , h 1,3 ,...h 1,118 , h 1,119 .
  • the AP estimates the channel information of the subcarriers allocated by the data stream 1 in the second LTF, that is, h 2,3 , h 2,7 , h 2,11 ,...h 2,115 , h 2,119 ;
  • a general or traditional interpolation algorithm obtains channel information for 119 subcarriers, namely h 2,1 , h 2,2 , h 2,3 ,...h 2,118 , h 2,119 , comparing h 1,1 ,h 1,2 ,h 1 , 3 , ... h 1,118 , h 1,119 and h 2,1 , h 2,2 , h 2,3 ,...h 2,118 , h 2,119 obtain the frequency shift v 1 of data stream 1 .
  • the AP can compensate the channel information, and the AP compensates the channel information of the data stream estimated in the second LTF, that is, X ⁇ 3,7,11,...115,119 ⁇ ; Similarly, in the third LTF, the AP can perform phase rotation compensation on the channel information of the data stream 1 estimated in the third LTF, that is, X ⁇ 121,125,129...233,237 ⁇ . Finally, the AP may perform phase rotation compensation on the channel information of the data stream 1 estimated in the fourth LFT, that is, X ⁇ 123,127,131...235,239 ⁇ .
  • the AP After the phase rotation adjustment, the AP obtains the channel information of the subcarrier index of the data stream 1 by 1, 4, 5, 7, 9, ... 235, 237, 239 through the four LTFs.
  • the first difference is 2, and the AP can obtain channel information of all subcarriers of the data stream 1, that is, channel information with subcarrier indexes of 1, 2, 3, 4, . . . , 238, 239, and 240.
  • the first interpolation is to estimate the frequency offset value to compensate for the channel estimates of the remaining LTFs other than the first LTF.
  • the AP updates the corresponding channel estimation value, that is, the subcarrier, according to the subcarriers occupied by the data stream 1 in each LTF.
  • the index is channel information of 1, 3, 5, 7, 9, ...
  • the secondary interpolation may be performed according to the updated subcarrier channel values (channel information of subcarrier indices of 1, 3, 5, 7, 9, ... 235, 237, 239) to obtain channel values of all subcarriers of data stream 1. That is, the channel information of the subcarrier index is 1, 2, 3, 4..., 238, 239, 240.
  • an embodiment of the present invention provides a station, which is applied to a wireless local area network that uses an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams; include:
  • a symbol generating module 601 configured to generate a plurality of long training sequence symbols LTF, where any data stream sent by the station is allocated R subcarriers on the multiple LTFs, and the R subcarriers are used to carry a channel estimation sequence Include, in the plurality of LTFs, a first LTF and a second LTF, wherein, for any of the data streams: an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF An index, and an index of an ith subcarrier of the channel estimation sequence for carrying the data stream in the second LTF, wherein i is a positive integer less than or equal to F, where F is Determining, in a first LTF or a second LTF, a total number of subcarriers for carrying a channel estimation sequence of the data stream; and, the first LTF or the second LTF is used to carry a channel estimate of the data stream
  • the second difference between the indexes of the adjacent subcarriers of the sequence is twice the first difference;
  • the sending module 602 is configured to send the multiple long training sequences LTF.
  • N g ceil(N ST /R)
  • the symbol generating module 601 is further configured to determine a value of F by using a formula floor(R/I), where the F is greater than or equal to floor(R/I), and the floor operation is Down, I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil (S tot / N g ), and S tot is the number of the plurality of data streams;
  • floor(R/I) where the F is greater than or equal to floor(R/I), and the floor operation is Down
  • I is the total number of LTFs sent in any of the data streams
  • S tot is the number of the plurality of data streams
  • the subcarriers allocated to different data streams for carrying the channel estimation sequence are different.
  • the site also includes:
  • a receiving module configured to receive LTF indication information sent by an access point AP, where the LTF indication information is used to indicate, in a total of all LTFs sent in any one of the data streams, the sub-carrier for the channel estimation sequence Carrier index.
  • the embodiment further provides an access point, which is applied to a wireless local area network that adopts an uplink MU-MIMO technology, where the wireless local area network includes multiple stations and an access point AP to transmit multiple data streams;
  • Access points include:
  • the receiving module 701 is configured to receive, by the AP, a plurality of long training sequence symbols LTF.
  • the multiple LTFs include a first LTF and a second LTF, where the first LTF and the first LTF are The following relationship needs to be met between the two LTFs:
  • An index of an ith subcarrier of a channel estimation sequence for carrying the data stream in the first LTF, and an ith subcarrier of a channel estimation sequence for carrying the data stream in the second LTF A specific first difference is satisfied between the indices, where i is a positive integer less than or equal to F, and F is a total of subcarriers of the channel estimation sequence for carrying the data stream in the first LTF or the second LTF a quantity; and an index of the subcarrier that satisfies the first difference relationship in the first LTF is the first sub a carrier index sequence, where the index of the subcarrier that satisfies the first difference relationship in the second LTF is a second subcarrier index sequence;
  • the first LTF or the second LTF needs to satisfy a relationship that a second difference between the indices of adjacent subcarriers of the sequence of the first LTF or the second LTF for carrying the data stream for channel estimation is Describe the first difference of 2 times;
  • the F is greater than or equal to floor(R/I), where the floor operation is rounded down, I is the total number of LTFs sent in any of the data streams, and I satisfies I ⁇ ceil(S tot /N g And S tot is the number of the plurality of data streams; and in any of the LTFs, the subcarriers allocated to different data streams for carrying the channel estimation sequence are different.
  • the offset determining module 702 is configured to obtain a frequency offset value between the any one of the stations and the AP according to the multiple long training sequence symbols LTF.
  • the offset determining module 702 in the solution provided by the embodiment of the present invention specifically includes:
  • a channel information estimating module configured to: after receiving the plurality of long training sequence symbols LTF, estimate that any data stream sent by any station is allocated a channel for carrying R channel subcarriers of the channel estimation sequence on the multiple LTFs information;
  • An acquiring module configured to acquire a first subcarrier index sequence from the first LTF, and obtain a second subcarrier index sequence from the second LTF;
  • An interpolation module configured to determine, according to the first subcarrier index sequence and the second subcarrier index sequence, first channel information and second channel information corresponding to the data stream, respectively, to the first channel information and Performing an interpolation operation on the two channels of information to obtain third channel information and fourth channel information;
  • the interpolation module is further configured to determine a location of any channel information inserted by using the formula floor(N g /2)+1, wherein a distance between the first index and the second index corresponding to any channel information inserted is less than It is equal to floor(N g /2)+1, and the second index is one of a plurality of indexes corresponding to the R subcarriers.
  • an offset determining module configured to send, according to the third channel information and the fourth channel information, a frequency offset value between the any one of the stations and the AP.
  • the station sends the LTF according to a certain rule, so that the AP separately estimates part of the channel information of a data stream in the received multiple LTFs, and obtains the data stream according to the partial channel information.
  • the frequency offset value between the station and the AP so that the phase information corresponding to the channel information of different LTFs is compensated accordingly, so that the influence of phase rotation on the channel estimation can be avoided. Avoiding the orthogonality of the P matrix is affected by the carrier carrier frequency offset, which affects the correctness of the channel estimation.
  • the receiving end may perform the minimum distance interpolation operation on the two LTF channel estimates in a data stream before performing channel estimation, and compare the phases between the two interpolated channel information to obtain the
  • the frequency offset of the data stream further obtains the phase rotation of each LTF, and the receiving end can perform phase rotation compensation on the channel information estimated by each LTF, and align the influence of the phase rotation to the first LTF, thereby avoiding phase rotation.
  • the effect of the channel estimation is improved, and the constellation points appear to be greatly disordered when the data is subsequently decoded.
  • the constellation point map when data is decoded after channel estimation using the method of the present invention is as shown in FIG.
  • the disclosed system, apparatus and The method can be implemented in other ways.
  • the device embodiments described above are merely illustrative.
  • the division of the modules or units is only a logical function division.
  • there may be another division manner for example, multiple units or components may be used. Combinations can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • 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, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may be physically included separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.
  • the integrated unit if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium.
  • a computer readable storage medium A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of the methods described in various embodiments of the present application.
  • the foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Transmission System (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention se rapporte au domaine technique des communications mobiles. L'invention concerne un procédé et un appareil de transmission d'informations, qui s'appliquent à un réseau local sans fil adoptant la technologie MU-MIMO en liaison montante, le réseau local sans fil comprenant une pluralité de stations, de sorte à transmettre une pluralité de flux de données avec des points d'accès (AP). Le procédé consiste à : générer, au moyen des stations, une pluralité de symboles de champ d'apprentissage long (LTF), R sous-porteuses étant attribuées, sur la pluralité de LTF, à un flux de données quelconque transmis par les stations en vue d'acheminer des séquences d'estimation de canal, et la pluralité de LTF comprenant un premier LTF et un second LTF qui remplissent une condition définie ; et transmettre, au moyen des stations, la pluralité de champs d'apprentissage longs (LTF). Le procédé et l'appareil décrits par la présente invention résolvent le problème de l'état de la technique selon lequel l'exactitude d'estimation de canal est altérée du fait que l'orthogonalité d'une matrice P est altérée par le décalage des fréquences porteuses des stations.
PCT/CN2014/089589 2014-10-27 2014-10-27 Procédé et appareil de transmission d'informations WO2016065515A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2014/089589 WO2016065515A1 (fr) 2014-10-27 2014-10-27 Procédé et appareil de transmission d'informations

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2014/089589 WO2016065515A1 (fr) 2014-10-27 2014-10-27 Procédé et appareil de transmission d'informations

Publications (1)

Publication Number Publication Date
WO2016065515A1 true WO2016065515A1 (fr) 2016-05-06

Family

ID=55856339

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2014/089589 WO2016065515A1 (fr) 2014-10-27 2014-10-27 Procédé et appareil de transmission d'informations

Country Status (1)

Country Link
WO (1) WO2016065515A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4024801A4 (fr) * 2019-09-12 2022-10-26 Huawei Technologies Co., Ltd. Procédé d'estimation de canal multi-utilisateur en liaison montante, station et point d'accès

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110211594A1 (en) * 2008-08-19 2011-09-01 Qualcomm Incorporated Training sequences for very high throughput wireless communication
CN102714631A (zh) * 2010-01-12 2012-10-03 三星电子株式会社 在多用户多输入多输出系统中产生前同步码的方法以及使用所述方法的数据发送设备和用户终端
CN103004105A (zh) * 2010-07-28 2013-03-27 英特尔公司 用于上行链路多用户mimo mac支持的技术

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110211594A1 (en) * 2008-08-19 2011-09-01 Qualcomm Incorporated Training sequences for very high throughput wireless communication
CN102714631A (zh) * 2010-01-12 2012-10-03 三星电子株式会社 在多用户多输入多输出系统中产生前同步码的方法以及使用所述方法的数据发送设备和用户终端
CN103004105A (zh) * 2010-07-28 2013-03-27 英特尔公司 用于上行链路多用户mimo mac支持的技术

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4024801A4 (fr) * 2019-09-12 2022-10-26 Huawei Technologies Co., Ltd. Procédé d'estimation de canal multi-utilisateur en liaison montante, station et point d'accès
US11902054B2 (en) 2019-09-12 2024-02-13 Huawei Technologies Co., Ltd. Uplink multi-station channel estimation method, station, and access point

Similar Documents

Publication Publication Date Title
EP3143820B1 (fr) Appareil et procédé d'attribution de tonalité ofdma dans des réseaux wi-fi de prochaine génération
US10230436B2 (en) Methods for channel information acquisition, signal detection and transmission in multi-user wireless communication systems
US10270496B2 (en) Apparatus and method for transmitting/receiving signal in wireless communication system supporting distributed antenna system
US9544171B2 (en) Zero insertion for ISI free OFDM reception
RU2660162C2 (ru) Однопотоковое отслеживание фазы в ходе оценивания канала в системе беспроводной связи mimo с очень высокой пропускной способностью
CN110999187B (zh) 无线通信系统中分配相位跟踪参考信号的方法和装置
CN108632189B (zh) 上行数据的发送方法、装置及用户设备
US8638882B2 (en) Method and apparatus for offset estimation in mobile communication system
KR20130105828A (ko) 통신 시스템에서 채널 설명 피드백
TWI449367B (zh) Channel estimation method, pilot information selection method, user equipment and base station
US10284280B2 (en) Method, system and device for compensation of Doppler impairments in OFDM wireless communication networks
CN110166087B (zh) Iq失衡下导频复用大规模mimo-ofdm无线通信方法
US8073070B2 (en) Multi-pilot generation method and detection method in multi-antenna communication system
WO2016019519A1 (fr) Procédé et appareil pour transmettre des informations de liaison montante multi-utilisateur dans un système entrée multiple sortie multiple
CN107005322B (zh) 与多个无线通信装置同时通信的系统和方法
RU2471298C2 (ru) Способы и системы для выбора циклических задержек в оfdm-системах с множеством антенн
CN107294678A (zh) 用于信道估计的方法和通信设备
US8331482B2 (en) System and method for subcarrier allocation and permutation
WO2016065515A1 (fr) Procédé et appareil de transmission d'informations
CN106685625A (zh) 一种导频结构、导频发送方法以及用户信道估计方法
EP3157216B1 (fr) Procédé et dispositif d'acquisition de données de liaison descendante dans un système mimo à grande échelle
US20170012752A1 (en) Uplink Multi-User-MIMO without Client Assistance
WO2015085820A1 (fr) Procédé de détermination d'agencement de fréquence pilote et station de base
CN107005525B (zh) 无线局域网中的导频传输方法及数据传输装置
WO2016095092A1 (fr) Procédé, appareil et système permettant d'envoyer et de recevoir des informations dans un réseau local sans fil

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14904912

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14904912

Country of ref document: EP

Kind code of ref document: A1