CN106789767B - Distributed C/S I estimation and dynamic updating method in a kind of WLAN - Google Patents
Distributed C/S I estimation and dynamic updating method in a kind of WLAN Download PDFInfo
- Publication number
- CN106789767B CN106789767B CN201611083885.1A CN201611083885A CN106789767B CN 106789767 B CN106789767 B CN 106789767B CN 201611083885 A CN201611083885 A CN 201611083885A CN 106789767 B CN106789767 B CN 106789767B
- Authority
- CN
- China
- Prior art keywords
- csi
- user
- channel
- date
- frame
- Prior art date
- Legal status (The legal status 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 status listed.)
- Active
Links
Classifications
-
- 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
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0417—Feedback systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0452—Multi-user MIMO systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
- H04B7/0621—Feedback content
- H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
The invention discloses Distributed C/S I estimation and dynamic updating methods in a kind of WLAN, the end AP is reduced to the pressure of channel plan by the way that channel estimation to be distributed to user terminal in a manner of competing, timing is carried out to the channel state information CSI of each user in the end AP simultaneously, CSI is dynamically updated by CSI dynamic update algorithm, to reduce unnecessary channel estimation, and then compression channel estimates expense in the time domain, to improve the communication efficiency of multiuser MIMO, improves WLAN handling capacity.
Description
Technical field
The present invention relates in wireless communication technical field field, the channel estimation of WLAN distributed access systems and
It updates, particularly relates to Distributed C/S I estimation and dynamic updating method in a kind of WLAN.
Background technique
With the universal of smart phone, the fast development of the extensive application of wearable device and multimedia service, the whole world is moved
The growth of blowout is presented in dynamic data.According to the prediction address of Cisco System Co., until 2019, global radio data traffic will be worked as
Ten times of preceding data volume, reach 300,000,000,000 GB, at that time global radio communication equipment, and especially the popularity rate of intelligent mobile terminal will
Reach 70%.The data service of magnanimity is the growth that conventional wireless network framework bring is not only the traffic, and multiple types are convenient
Quick wireless data access mode is also current one of main problem, using WiFi as WLAN (WLAN) skill of representative
Art has been that people widely use.
Multiple-input and multiple-output (MIMO) technology is theoretical since being used by wlan standard IEEE 802.11n agreement
It confirms WLAN can be supported to possess higher rate and more reliable transmission in spatial domain with practice.Newest wlan standard
The IEEE802.11ac and generation standard IEEE802.11ax in breeding, has more received multiuser MIMO (MU-MIMO) skill
Art, exponentially to increase downlink transmission data.In order to transmit data to multiple users simultaneously, and data between user are not caused
The interference of stream needs to estimate wireless channel, obtains channel state information (CSI, Channel State
Information), by beam forming (Beamforming) technology, precoding is carried out in transmitting terminal, to offset different spaces
Interference between stream.Therefore, CSI estimation and its efficiency become the key technology for restricting WLAN multi-user MIMO transmissions.
This patent is intended to the CSI estimation to current 802.11ac agreement and updates improve, and improves the effect of CSI estimation
Rate to improve the feasibility and performance of multiuser MIMO, and then improves the handling capacity and service quality of network.
Due to the opening and variability of WLAN channel, it has proved that in multiuser MIMO beam forming in application, using
Explicit channel feedback (explicit feedback) is more advantageous to raising system performance.And explicit feedback channels status information
The side effect efficiency of whole system that has been exactly the cost reduction in time domain.Although 802.11ac is in time domain, frequency domain, precision
Three aspects compress channel state information, but when userbase increases, the expense of time domain still be will be greatly reduced
The performance of multiuser MIMO even results in the deterioration of whole system performance.Meanwhile using orthogonal frequency division multiplexing (OFDM) technology
WLAN needs to carry out the planning of channel on each subcarrier in frequency range, and the complexity of exhaust algorithm is to pursue low complex degree hardware
Commercial access point (AP, Access Point) institute it is unacceptable.
These problems are just limited to, multiuser MIMO not yet large-scale application is in commercial product.In fact, stationary user
Channel coherency time be enough to transmit several data cells, and the channel coherency time of the user moved then much shorter is current to assist
It there are in fact overestimation for each packet progress channel estimation in view.And each channel estimation of 802.11ac agreement is all
The CSI that all users can be transmitted is carried out unified planning by AP, but the final multiuser MIMO upper limit only has 4 road spatial flows, when
When number of users increases, only AP does not bring huge calculating pressure, more causes the waste of a large amount of CSI information transmission time.
Summary of the invention
In view of this, being used it is an object of the invention to propose Distributed C/S I estimation and dynamic updating method in a kind of WLAN
To improve the communication efficiency of multiuser MIMO, WLAN handling capacity is improved.
Based on Distributed C/S I estimation and dynamic updating method in a kind of above-mentioned purpose WLAN provided by the invention, comprising:
S10, AP competition obtain channel control, and multiuser MIMO downlink transfer starts；
The each AC of S11, AP is competed by EDCA, determines the major and minor status AC, and the point of destination of first packet of main AC is set as
Primary user, and send NDPA packet；
S12, AP send NDP packet after sending NDPA packet, and all users of AP pass through NDP packet physical frame header respectively and carry out letter
Road is estimated to obtain itself CSI, judges whether itself CSI is expired and updates coherence window value according to coherent condition；
S13, the primary user respond itself CSI to AP, and other users are kept silent and waited, and AP updates primary after receiving
Family CSI, and primary user is added and has selected user group；
Not out of date CSI in S14, AP ergodic data library has been selected in family in any not out of date CSI of judgement with described
After all subscriber channels are orthogonal, by short signaling communication update the not out of date CSI correspond to user coherence window value, by its
Addition has selected user group and has been that current spatial stream chooses suitable modulation and coding strategy according to feedback signal-to-noise ratio；
S15, AP, which choose, has selected the channel that all subscriber channels are orthogonal in user group with described, sends probe frame, institute respectively
Have be not added the user for having selected user group pass through CSI competition obtain transmission opportunity；
S16, AP are according to channel estimation results encoding transmission data frame.
Optionally, the S14 is specifically included:
S20, AP choose not out of date CSI in the database, judge the not out of date CSI whether with selected in user group
All subscriber channels are orthogonal, if then corresponding to user to the not out of date CSI sends SOT state of termination claim frame；
S21, the not out of date CSI correspond to user and receive SOT state of termination claim frame, respond SOT state of termination frame to AP, described
Information includes that whether primary user CSI is expired, receives signal-to-noise ratio and coherence window value in SOT state of termination frame；
S22, AP receive the SOT state of termination frame frame of user feedback, update the relevant window that the not out of date CSI corresponds to user
Mouth value；If CSI is not out of date, which is added and has selected user group and has been that current spatial stream is chosen properly according to feedback signal-to-noise ratio
Modulation and coding strategy；If CSI is out of date, user's CSI renewal time in database is reset；
S23 judges whether still there is the not out of date user of CSI in database, if so then execute step S20, if otherwise executing step
Rapid S15.
Optionally, the S15 is specifically included:
S30, AP judge whether to have used up all spatial degrees of freedom；S31 is thened follow the steps if not, is thened follow the steps if not
S16；
S31, AP calculate the channel orthogonal with all subscriber channels of selected user group, and send probe to these directions
Frame；
S32, all unselected user's monitor channels, quantization probe frame signal-to-noise ratio participate in competition, possess signal-to-noise ratio maximum
User obtain transmission opportunity and to AP return CSI；
S33, AP receive CSI, and CSI is corresponded to user's addition and has selected user group, updates itself CSI and CSI renewal time；It executes
Step S30.
Optionally, the S32 is specifically included:
S40, in whole probe frames that the unselected user selection listens to the maximum probe frame of received signal to noise ratio into
Row noise is ratio, is mapped as 8 binary quantization values；
S41, in subsequent 8 time slots, the quantized value of each unselected user corresponds to position and then sends one if " 1 "
Signal, if " 0 " then monitor channel；If any unselected user listens to other users and sends signal, competition is exited；
S42, after completing 8 slot contentions, if 2 or 2 remaining or more user, AP stops subsequent CSI competition, by existing
Channel information carry out the transmission of multiuser MIMO data；If remaining 1 user, the user return to its CSI to AP.
Optionally, in the S12, all users of AP pass through NDP packet physical frame header progress channel estimation respectively and obtain certainly
Body CSI judges whether itself CSI is expired and updates coherence window value, specifically includes according to coherent condition:
S50, user calculate own channel coherence factor, judge whether itself coherence factor is less than predetermined threshold value；If small
In then determining that the user CSI is expired, update user terminal CSI and channel renewal time；If being not less than, the user is determined
CSI is not out of date；
S51, judges whether channel estimation interval is greater than channel coherence window；If CSI is expired and channel estimation interval is greater than
Coherence window or CSI is not out of date and channel estimation interval is less than coherence window, then channel coherence window is constant；If CSI is expired
And channel estimation interval is less than channel coherence window, then channel coherence window reduces；If CSI is not out of date and channel estimation interval is big
In coherence window, then channel coherence window increases.
Optionally, the channel coherence factor calculating formula is as follows:Wherein L is
The overall length of channel gain sampling, T are coherence time, and h (t) is gain matrix/vector of present channel.
Optionally, the difference of current time Yu upper secondary channel renewal time was divided between the channel estimation；The channel phase
Dry window is user terminal and the dynamic estimation value to channel coherency time that the end AP stores；The channel coherence window is in user terminal
Update when receiving NDP every time, is updated in the terminal response process that the end AP carries out MU-MIMO every time.
From the above it can be seen that Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention,
The end AP is reduced to the pressure of channel plan by the way that channel estimation to be distributed to user terminal in a manner of competing, while every to the end AP
The channel state information CSI of a user sets timer, dynamically updates CSI by CSI dynamic update algorithm, need not with reduction
The channel estimation wanted, and then compression channel estimates expense in the time domain, thus lifting system performance.
Detailed description of the invention
Fig. 1 is one embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram；
Fig. 2 is another embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram；
Fig. 3 is the another embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram；
Fig. 4 is the alternative embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram；
Fig. 5 is terminal in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
The frame structure schematic diagram of status request frame；
Fig. 6 is terminal in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
The frame structure schematic diagram of status frames；
Fig. 7 is to be distributed in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Formula channel estimation probe direction schematic diagram；
Fig. 8 is that CSI is competing in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Strive the schematic diagram of mechanism；
Fig. 9 is a practical application of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
The schematic diagram of citing.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with specific embodiment, and reference
Attached drawing, the present invention is described in more detail.
It should be noted that all statements for using " first " and " second " are for differentiation two in the embodiment of the present invention
The non-equal entity of a same names or non-equal parameter, it is seen that " first " " second " only for the convenience of statement, does not answer
It is interpreted as the restriction to the embodiment of the present invention, subsequent embodiment no longer illustrates this one by one.
Fig. 1 is one embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram.As shown, being based on above-mentioned purpose, Distributed C/S I in a kind of WLAN is provided in one aspect of the invention and is estimated
Meter and dynamic updating method, comprising:
S10, AP competition obtain channel control, and multiuser MIMO downlink transfer starts.
The each AC of S11, AP is competed by EDCA, determines the major and minor status AC, and the point of destination of first packet of main AC is set as
Primary user, and send NDPA packet.
S12, AP send NDP packet after sending NDPA packet, and all users of AP pass through NDP packet physical frame header respectively and carry out letter
Road is estimated to obtain itself CSI, judges whether itself CSI is expired and updates coherence window value according to coherent condition.
S13, the primary user respond itself CSI to AP, and other users are kept silent and waited, and AP updates primary after receiving
Family CSI, and primary user is added and has selected user group.
Not out of date CSI in S14, AP ergodic data library has been selected in family in any not out of date CSI of judgement with described
After all subscriber channels are orthogonal, by short signaling communication update the not out of date CSI correspond to user coherence window value, by its
Addition has selected user group and has been that current spatial stream chooses suitable modulation and coding strategy according to feedback signal-to-noise ratio.
S15, AP, which choose, has selected the channel that all subscriber channels are orthogonal in user group with described, sends probe frame, institute respectively
Have be not added the user for having selected user group pass through CSI competition obtain transmission opportunity.
S16, AP are according to channel estimation results encoding transmission data frame.
In step S11, EDCA (visit by Enhanced Distributed Channel Access, enhanced distributed channel
Ask) it is the new MAC layer access mechanism proposed in IEEE 802.11e, the concept of the grade of service is introduced, is increased some new
Qos parameter and frame structure, enhance the QoS performance of WLAN.
In step S11, NDPA packet is a kind of detection agreement (VHT Sounding defined in 802.11ac agreement
Protocol the data frame for including in), the agreement can allow receiving end to have an opportunity to help to be sent to preferably to carry out beam forming
Work；Similarly the NDP packet in step S12 is also the data frame in above-mentioned detection agreement.
In step S14, mainly include in the database following data (each accessing user's): user AID
(Association identifier, associated identifiers), (last time updates) subscriber channel renewal time, subscriber channel
More new window, whether channel is expired, (last time updates) user CSI.
From the step of the present embodiment can be seen that method provided in this embodiment by channel estimation in a manner of competing
It is distributed to user terminal and reduces the end AP to the pressure of channel plan, while the channel state information CSI of each user in the end AP is set
Determine timer, CSI is dynamically updated by CSI dynamic update algorithm, to reduce unnecessary channel estimation, and then in the time domain
Compression channel estimates expense, thus lifting system performance.
Fig. 2 is another embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram.As shown, the S14 is specifically included in another embodiment:
S20, AP choose not out of date CSI in the database, judge the not out of date CSI whether with selected in user group
All subscriber channels are orthogonal, if then corresponding to user to the not out of date CSI sends SOT state of termination claim frame.
S21, the not out of date CSI correspond to user and receive SOT state of termination claim frame, respond SOT state of termination frame to AP, described
Information includes primary user CSI whether expired, received signal to noise ratio and coherence window value in SOT state of termination frame.
S22, AP receive the SOT state of termination frame of user feedback, update the coherence window that the not out of date CSI corresponds to user
Value；If CSI is not out of date, S22.1 is executed, the user is selected to carry out multiuser MIMO, which is added and has selected user group, it will
The user be added selected user group and according to feedback signal-to-noise ratio be current spatial stream choose suitable modulation and coding strategy (MCS,
Modulation and Coding Scheme)；If CSI is out of date, S22.2 is executed, the user is not selected to carry out multi-user
MIMO, resets user's CSI renewal time in database, which is ready for CSI competition.
S23 judges whether still there is the not out of date user of CSI in database, if so then execute step S20, if otherwise executing step
Rapid S15.
Fig. 5 is terminal in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
The frame structure schematic diagram of status request frame；Fig. 6 is Distributed C/S I estimation and dynamic update side in a kind of WLAN provided by the invention
The frame structure schematic diagram of SOT state of termination frame in the embodiment of method.With reference to attached drawing as it can be seen that the SOT state of termination claim frame (DSR,
Destination State Request) it include Frame Control, Duration, RA, TA, STA Info and FCS field,
The SOT state of termination frame (DS, Destination State) includes Frame Control, Duration, RA, Sounding
Response and FCS field.Wherein Frame Control, Duration, RA, TA, FCS respectively represent frame control field, frame length
(duration) receives station address, hair station address, Frame Check Sequence, identical with the definition of current 802.11 standard, in the hope of simultaneous
Hold.
The STA Info field in SOT state of termination claim frame, further includes AID12, Feedback Type and Nc
Tri- subfields of Index；Wherein AID12 is the association identification of 12bit；Feedback Type refers to that single user/multiuser channel is anti-
Feedback, 0 is single user, and 1 is multi-user, this field should be fixed as 1 here；Nc Index is the matrix size of channel feedback, value
Size is Nc-1；STA Info field setting in the above DSR frame is compatible with 802.11 standards.
Sounding Response field in SOT state of termination frame, further includes Response, SNR Map
Tri- subfields of Value and Coherence Window；Wherein Response represents user and judges whether CSI is expired, if expired
Its value is 0, its not out of date value is 1；SNR Map Value is signal-to-noise ratio quantized value, is selected for MCS；Coherence
Window is channel coherence window value.The above Sounding Response field, without similar definitions, needs in 802.11 standards
Additional code is added to realize.
From the above it can be seen that the present embodiment is by customized SOT state of termination claim frame and SOT state of termination frame, it is real
The short signaling interaction between AP and user is showed, so that it is determined that channel status, updates coherence window and feed back signal-to-noise ratio.
Fig. 3 is the another embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram.Fig. 7 is to divide in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Cloth channel estimation probe direction schematic diagram.As shown, in another embodiment, the S15 is specifically included:
S30, AP judge whether to have used up all spatial degrees of freedom；S31 is thened follow the steps if not, if so then execute step
S16。
S31, AP calculate the channel orthogonal with all subscriber channels of selected user group, and send probe to these directions
Frame.
S32, all unselected user's monitor channels, quantization probe frame signal-to-noise ratio participate in competition, possess signal-to-noise ratio maximum
User obtain transmission opportunity and to AP return CSI.
S33, AP receive CSI, and CSI is corresponded to user's addition and has selected user group, updates itself CSI and CSI renewal time；It executes
Step S30.
Wherein, in step S30, it is that user terminal receives antenna sum and is equal to that the condition of all spatial degrees of freedom is used up in judgement
The end AP available antenna sum.In addition, the multiuser MIMO downlink in the embodiment of the present application is most in order to compatible with 802.11ac standard
Big parallel transmission number of users is 4.
Preferably, the S32 is specifically included:
S40, in whole probe frames that the unselected user selection listens to the maximum probe frame of received signal to noise ratio into
Row noise is ratio, is mapped as 8 binary quantization values.
S41, in subsequent 8 time slots, the quantized value of each unselected user corresponds to position and then sends one if " 1 "
Signal, if " 0 " then monitor channel；If any unselected user listens to other users and sends signal, competition is exited.
S42, after completing 8 slot contentions, if 2 or 2 remaining or more user, AP stops subsequent CSI competition, by existing
Channel information carry out the transmission of multiuser MIMO data；If remaining 1 user, the user return to its CSI to AP.
Fig. 8 is that CSI is competing in the embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
The schematic diagram for striving mechanism, with reference to attached drawing, in the present embodiment, signal-to-noise ratio size should be mapped as the integer quantisation value N of 8bit when quantization
(SNR) (it is recommended that carrying out Linear Mapping), and (time slot here is different from the backoff period of 802.11ac, user by 8 time slots
Whether the transmission signal power for needing to judge other stations is more than threshold value, therefore is not grown the time required to each time slot herein, specifically
Send and receive that state conversion time is related the time with each station radio-frequency front-end, in the preferred embodiment obtained by simulation, Wo Menshe
The time of each time slot is 27us, i.e. 3 802.11 standard backoff period durations in this fixed 8 time slots) it is at war with.User exists
When each time slot, judging that time-slot sequence corresponds to the numerical value of quantized value position as " 1 " is still " 0 ", is if quantitative graphs correspond to position
" 1 ", then the user sends a signal, corresponds to the user if position is " 0 " if quantitative graphs and does not send signal and monitor channel；
If listening to other users sends signal, other users are represented in corresponding signal-to-noise ratio quantization and are greater than this user, therefore are stopped
Competition, the station for being finally successfully transmitted all 8 time slots is the maximum station of quantitative graphs, it wins competition and transmits CSI.There is very little
Competition is clashed to channel simultaneously at possibility two stations, AP should stop subsequent CSI and compete at this time, be believed by existing channel
Breath carries out the transmission of multiuser MIMO data.
Fig. 4 is the alternative embodiment of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
Flow diagram.As shown, in the S12, all users of AP pass through NDP packet object respectively in an optional embodiment
Reason frame head carries out channel estimation and obtains itself CSI, judges whether itself CSI is expired and updates relevant window according to coherent condition
Mouth value, specifically includes:
S50, user calculate own channel coherence factor, judge whether itself coherence factor is less than predetermined threshold value；If small
In then determining that the user CSI is expired, updating user terminal CSI and channel renewal time if being not less than determines the user
CSI is not out of date.
S51, judges whether channel estimation interval is greater than channel coherence window；If CSI is expired and channel estimation interval is greater than
Coherence window or CSI is not out of date and channel estimation interval is less than coherence window, then channel coherence window is constant；If CSI is expired
And channel estimation interval is less than channel coherence window, then channel coherence window reduces；If CSI is not out of date and channel estimation interval is big
In coherence window, then channel coherence window increases.The logic flow of S51 is with specific reference to Fig. 4.
It should be noted that in step S12 and its sub-step, user terminal determines that CSI is expired and determines that CSI is expired with AP and be
What distribution carried out, it is nonsynchronous.Under all situations, user can be by NDP when carrying out descending multi-user MIMO transmission every time
Channel is assessed, coherence window is updated；AP can only compare coherence window and estimate the size of time interval to judge CSI's
Freshness.And only work as it and think just communicate with user when CSI is fresh (not out of date), whether CSI is confirmed to it
It can use；At this moment oneself channel estimation results (only CSI whether expired and coherence window) are fed back to AP by user, AP according to
Feedback result determines whether to be transferred to this user, but can all update window value regardless of whether CSI is expired.
Preferably, the channel coherence factor calculating formula is as follows:Wherein L is
The overall length of channel gain sampling, T are coherence time, and h (t) is gain matrix/vector of present channel.This formula is 802.11 marks
The channel coherence factor suggested in standard seeks formula.
In some preferred embodiments, the difference of current time Yu upper secondary channel renewal time was divided between the channel estimation
Value；The channel coherence window is user terminal and the dynamic estimation value to channel coherency time that the end AP stores, and range is 0-
1024 (10bit), unit millisecond (ms), the update when user terminal receives NDP every time of channel coherence window carry out every time at the end AP
It is updated in the terminal response process of MU-MIMO.Channel coherence window initial value suggestion is 16ms, it is proposed that increases and reduce strategy
For exponential increase, it can guarantee that mobile subscriber and static subscriber can comparatively fast converge to suitable coherence window value in this way.It is described
The update when user terminal receives NDP every time of channel coherence window, the quilt in the terminal response process that the end AP carries out MU-MIMO every time
It updates.
Fig. 9 is a practical application of Distributed C/S I estimation and dynamic updating method in a kind of WLAN provided by the invention
The schematic diagram of citing.As shown, user 1 is primary user, user 2 has initiated SOT state of termination response since the end AP CSI is not out of date
Process, and it is not out of date to be successfully authenticated CSI receives after DS frame AP for user 2 and is added to selected user group, is not found
CSI not out of date and all orthogonal with user 1 and 2 channel of user user, therefore have sent orthogonal with user 1 and 2 channel of user
Probe, every other user by N (SNR) leading competition, user 3 and user 4 win in two-wheeled competition respectively and to
AP transfers CSI, and so far AP spatial degrees of freedom uses up (while the number of users upper limit for also having reached MU-MIMO), passes through user
The CSI of 1-4 encodes data frame, completes downlink MU-MIMO transmission.
The present invention is that distributed channel estimation and CSI dynamic updating method, advantage are in a kind of WLAN:
(1) a kind of distributed channel estimation methods are proposed: by probe by channel coherence assessment be distributed to it is all
User's parallel processing, not only effectively reduce AP burden, but also greatly reduce unnecessary CSI transmission, reduce channel
Estimate time overhead, improves the efficiency of channel estimation.
(2) propose a kind of dynamic CSI update mechanism: dynamic, which updates CSI, can effectively match dynamic, static use
Family.CSI can be updated with the shorter time for dynamic subscriber and improve MU-MIMO performance, it can be effective for static user
The channel estimation of redundancy is reduced using longer channel coherency time, reduces channel estimation expense, raising efficiency.
(3) it introduces SOT state of termination request (DSR) and the SOT state of termination (DS) frame structure: by the interaction of DSR and DS frame, providing
A kind of efficient AP- user information interaction of low overhead, channel coherence window whether expired by CSI and signal-to-noise ratio etc.
Information exchange is effectively reduced CSI transmission frequency, while this method is that dynamic is reliable, it may be assumed that changes in User Status
Coherence window can be timely modulated (if any static state to dynamic) when change, feedback CSI is expired, so as to avoid due to User Status
Change transmission failure caused by bring CSI error.
It should be understood by those ordinary skilled in the art that: the discussion of any of the above embodiment is exemplary only, not
It is intended to imply that the scope of the present disclosure (including claim) is limited to these examples；Under thinking of the invention, above embodiments
Or can also be combined between the technical characteristic in different embodiments, step can be realized with random order, and be existed such as
Many other variations of the upper different aspect of the invention, for simplicity, they are not provided in details.
In addition, to simplify explanation and discussing, and in order not to obscure the invention, it can in provided attached drawing
It is connect with showing or can not show with the well known power ground of integrated circuit (IC) chip and other components.Furthermore, it is possible to
Device is shown in block diagram form, to avoid obscuring the invention, and this has also contemplated following facts, i.e., about this
The details of the embodiment of a little block diagram arrangements be height depend on will implementing platform of the invention (that is, these details should
It is completely within the scope of the understanding of those skilled in the art).Elaborating that detail (for example, circuit) is of the invention to describe
In the case where exemplary embodiment, it will be apparent to those skilled in the art that can be in these no details
In the case where or implement the present invention in the case that these details change.Therefore, these descriptions should be considered as explanation
Property rather than it is restrictive.
Although having been incorporated with specific embodiments of the present invention, invention has been described, according to retouching for front
It states, many replacements of these embodiments, modifications and variations will be apparent for those of ordinary skills.Example
Such as, discussed embodiment can be used in other memory architectures (for example, dynamic ram (DRAM)).
The embodiment of the present invention be intended to cover fall into all such replacements within the broad range of appended claims,
Modifications and variations.Therefore, all within the spirits and principles of the present invention, any omission, modification, equivalent replacement, the improvement made
Deng should all be included in the protection scope of the present invention.
Claims (6)
1. Distributed C/S I estimation and dynamic updating method in a kind of WLAN characterized by comprising
S10, AP competition obtain channel control, and multiuser MIMO downlink transfer starts；
The each AC of S11, AP is competed by EDCA, determines the major and minor status AC, and the point of destination of first packet of main AC is set as primary
Family, and send NDPA packet；
S12, AP send NDP packet after sending NDPA packet, and all users of AP pass through NDP packet physical frame header progress channel respectively and estimate
Meter obtains itself CSI, judges whether itself CSI is expired and updates coherence window value according to coherent condition；
User calculates own channel coherence factor, judges whether itself coherence factor is less than predetermined threshold value；If being less than, determine
The user CSI is expired, updates user terminal CSI and channel renewal time；If being not less than, determine that the user CSI is not out of date；
Judge whether channel estimation interval is greater than channel coherence window；If CSI is expired and channel estimation interval is relevant greater than channel
Window or CSI is not out of date and channel estimation interval is less than channel coherence window, then channel coherence window is constant；If CSI is expired
And channel estimation interval is less than channel coherence window, then channel coherence window reduces；If CSI is not out of date and channel estimation interval is big
In channel coherence window, then channel coherence window increases；
S13, the primary user respond itself CSI to AP, and other users are kept silent and waited, and AP updates primary user after receiving
CSI, and primary user is added and has selected user group；
Not out of date CSI in S14, AP ergodic data library is determining any not out of date CSI and the institute selected in user group
After having user's channel quadrature, the coherence window value of user is corresponded to by the short signaling communication update not out of date CSI, is added
Enter to have selected user group and is that current spatial stream chooses suitable modulation and coding strategy according to feedback signal-to-noise ratio；
S15, AP, which choose, has selected the channel that all subscriber channels are orthogonal in user group with described, sends probe frame, Suo Youwei respectively
Addition has selected the user of user group to compete by CSI and has obtained transmission opportunity；
S16, AP are according to channel estimation results encoding transmission data frame.
2. the method according to claim 1, wherein the S14 is specifically included:
S20, AP choose not out of date CSI in the database, judge the not out of date CSI whether with selected in user group own
Subscriber channel is orthogonal, if then corresponding to user to the not out of date CSI sends SOT state of termination claim frame；
S21, the not out of date CSI correspond to user and receive SOT state of termination claim frame, respond SOT state of termination frame, the terminal to AP
Information includes primary user CSI whether expired, received signal to noise ratio and coherence window value in status frames；
S22, AP receive the SOT state of termination frame of user feedback, update the coherence window value that the not out of date CSI corresponds to user；If
CSI is not out of date, then the user is added and has selected user group and be that current spatial stream chooses suitable modulation according to feedback signal-to-noise ratio
With coding strategy；If CSI is out of date, user's CSI renewal time in database is reset；
S23 judges whether still have the not out of date user of CSI to then follow the steps if not if so then execute step S20 in database
S15。
3. the method according to claim 1, wherein the S15 is specifically included:
S30, AP judge whether to have used up all spatial degrees of freedom；S31 is thened follow the steps, if not if so then execute step S16；
S31, AP calculate the channel orthogonal with all subscriber channels of user group have been selected, and send probe frame to these directions；
S32, all unselected user's monitor channels, quantization probe frame signal-to-noise ratio participate in competition, possess the maximum use of signal-to-noise ratio
Family obtains transmission opportunity and returns to CSI to AP；
S33, AP receive CSI, and CSI is corresponded to user's addition and has selected user group, updates itself CSI and CSI renewal time；Execute step
S30。
4. according to the method described in claim 3, it is characterized in that, the S32 is specifically included:
S40, the unselected user select the maximum probe frame of received signal to noise ratio in the whole probe frames listened to carry out letter
It makes an uproar ratio, is mapped as 8 binary quantization values；
S41, in subsequent 8 time slots, the quantized value of each unselected user corresponds to position and then sends a letter if " 1 "
Number, if " 0 " then monitor channel；If any unselected user listens to other users and sends signal, competition is exited；
S42, after completing 8 slot contentions, if 2 or 2 remaining or more user, AP stops subsequent CSI competition, passes through existing letter
Road information carries out the transmission of multiuser MIMO data；If remaining 1 user, the user return to its CSI to AP.
5. according to the method described in claim 4, it is characterized in that, the channel coherence factor calculating formula is as follows:Wherein L is the overall length of channel gain sampling, and T is coherence time, and h (t) is current
Gain matrix/vector of channel.
6. according to the method described in claim 5, it is characterized in that, being divided into current time and upper secondary channel between the channel estimation
The difference of renewal time；The channel coherence window is user terminal and the dynamic estimation to channel coherency time that the end AP stores
Value；Channel coherence window update when user terminal receives NDP every time carries out the terminal response of MU-MIMO at the end AP every time
It is updated in the process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611083885.1A CN106789767B (en) | 2016-11-30 | 2016-11-30 | Distributed C/S I estimation and dynamic updating method in a kind of WLAN |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611083885.1A CN106789767B (en) | 2016-11-30 | 2016-11-30 | Distributed C/S I estimation and dynamic updating method in a kind of WLAN |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106789767A CN106789767A (en) | 2017-05-31 |
| CN106789767B true CN106789767B (en) | 2019-10-18 |
Family
ID=58913703
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611083885.1A Active CN106789767B (en) | 2016-11-30 | 2016-11-30 | Distributed C/S I estimation and dynamic updating method in a kind of WLAN |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106789767B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019051818A1 (en) * | 2017-09-18 | 2019-03-21 | Hewlett Packard Enterprise Development Lp | Promoting channel access fairness |
| CN109547072B (en) * | 2017-09-22 | 2021-03-30 | 华为技术有限公司 | Method of channel sounding, communication device, and computer-readable storage medium |
| CN110366247B (en) * | 2018-03-26 | 2021-07-27 | 上海朗帛通信技术有限公司 | Method and device used in user equipment and base station for wireless communication |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102549992A (en) * | 2009-09-18 | 2012-07-04 | 高通股份有限公司 | Protocol to support adaptive station-dependent channel state information feedback rate in multi-user communication systems |
| CN102812649A (en) * | 2010-02-10 | 2012-12-05 | 马维尔国际贸易有限公司 | Transmission protection for wireless communications |
| CN103081420A (en) * | 2010-08-10 | 2013-05-01 | 马维尔国际贸易有限公司 | Sub-band feedback for beamforming on downlink multiple user MIMO configurations |
| CN103202085A (en) * | 2011-01-03 | 2013-07-10 | Lg电子株式会社 | Channel sounding method in wireless local area network system and apparatus for supporting the same |
| CN104853385A (en) * | 2015-05-25 | 2015-08-19 | 电子科技大学 | Dynamic mechanism for efficient information transmission in WIFI system based on OFDMA technology |
| CN105991179A (en) * | 2015-03-04 | 2016-10-05 | 华为技术有限公司 | Method and device for transmitting channel state information |
-
2016
- 2016-11-30 CN CN201611083885.1A patent/CN106789767B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102549992A (en) * | 2009-09-18 | 2012-07-04 | 高通股份有限公司 | Protocol to support adaptive station-dependent channel state information feedback rate in multi-user communication systems |
| CN102812649A (en) * | 2010-02-10 | 2012-12-05 | 马维尔国际贸易有限公司 | Transmission protection for wireless communications |
| CN103081420A (en) * | 2010-08-10 | 2013-05-01 | 马维尔国际贸易有限公司 | Sub-band feedback for beamforming on downlink multiple user MIMO configurations |
| CN103202085A (en) * | 2011-01-03 | 2013-07-10 | Lg电子株式会社 | Channel sounding method in wireless local area network system and apparatus for supporting the same |
| CN105991179A (en) * | 2015-03-04 | 2016-10-05 | 华为技术有限公司 | Method and device for transmitting channel state information |
| CN104853385A (en) * | 2015-05-25 | 2015-08-19 | 电子科技大学 | Dynamic mechanism for efficient information transmission in WIFI system based on OFDMA technology |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106789767A (en) | 2017-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8948152B2 (en) | Method of performing link adaptation procedure | |
| CN105493598B (en) | Method and apparatus for multiple user uplink | |
| CN110463059A (en) | The probing scheduling communicated for distributed MIMO in access point cluster | |
| CN101800578B (en) | Method for reducing downlink multipoint cooperation implicate feedback overhead | |
| CN107409013A (en) | For channel condition information probing and the method and apparatus of feedback | |
| CN110392985A (en) | Distributed MIMO communication is triggered in radio node cluster | |
| CN107409012A (en) | For channel condition information probing and the method and apparatus of feedback | |
| CN107431567A (en) | For channel condition information probing and the method and apparatus of feedback | |
| EP2904713B1 (en) | Scheduling transmission for multi-user, multiple-input, multiple-output data | |
| CN105493599A (en) | Methods and apparatus for multiple user uplink | |
| KR101585845B1 (en) | Method and system for dual-mode (single user and multi users) packet error rate based rate control in a wireless communication system | |
| CN103326844B (en) | Based on 802.11 agreement resource allocation methods in composite mode | |
| CN103270788A (en) | Method and apparatus of link adaptation in a wireless local area network system | |
| US9363686B2 (en) | Method and system for unified rate adaptation for SU-BF and MU-MIMO operation | |
| CN113796054B (en) | System and method for capability indication for wireless receiving stations | |
| CN106789767B (en) | Distributed C/S I estimation and dynamic updating method in a kind of WLAN | |
| CN110114990A (en) | Channel detection method, device and storage medium | |
| US20140211642A1 (en) | Method And System For Boosting Transmission Settings Based On Signal To Interference And Noise Ratio | |
| WO2011160387A1 (en) | Method and base station for scheduling resources of multiple input multiple output | |
| Heo et al. | Performance Comparison of SU-and MU-MIMO in 802.11 ax: Delay and Throughput | |
| CN103379064A (en) | Precoding method, system and device | |
| Chowdhury et al. | Performance analysis of CSMA/CA based MU-MIMO WLANs | |
| CN114630412A (en) | Power control method in wireless local area network and related device | |
| Zhang et al. | Design of relay selection in two-hop MIMO relaying systems |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |