WO2016107590A1

WO2016107590A1 - Downlink multi-user transmission method and device

Info

Publication number: WO2016107590A1
Application number: PCT/CN2015/100015
Authority: WO
Inventors: 田开波; 邢卫民; 姚珂
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-12-31
Filing date: 2015-12-30
Publication date: 2016-07-07
Also published as: CN105813141A

Abstract

Disclosed are a downlink multi-user transmission method and device, the method comprising: a station participating in downlink multi-user transmission adjusts an uplink transmission time for transmitting a wireless frame to an access point (AP), such that the wireless frame transmitted by the station can reach the AP within an allowed time error; the station transmits the wireless frame to the AP according to the uplink transmission time; and the wireless frame transmitted by each of the stations comprises first portion content and second portion content, the first portion content comprising information identifiable by a traditional station, and the second portion content comprising information of each of the stations.

Description

Downlink multi-user transmission method and device

Technical field

The present invention relates to the field of wireless communications, and in particular, to a downlink multi-user transmission method and apparatus.

Background technique

In a wireless local area network (WLAN), an access point site (AP, Access Point) and a plurality of non-AP stations (non-AP STAs) associated with the AP are formed. A basic service set (BSS, Basic Service Set) is shown in Figure 1. WLAN is mainly a time-division network based on a competitive access mechanism. In an infrastructure network, data can only be sent by one sender at a time, that is, when one site performs data transmission, other sites remain silent. The AP sends data to the non-AP STA, which is called downlink transmission. The non-AP STA sends data to the AP, which is called uplink transmission.

As more and more users use WLAN for data communication, the WLAN network load is also increasing, and as the number of users increases, the efficiency of WLAN networks will decline significantly. Therefore, the Institute of Electrical and Electronics Engineers (IEEE) has established a related task force to address the WLAN network efficiency problem, in which parallel multi-user data transmission is an alternative to solving network efficiency. technology. Parallel multi-user data transmission technology includes multi-user multiple-input multiple-output (MU-MIMO) technology (ie, spatial domain multiple access), orthogonal frequency division multiple access (OFDMA, Orthogonal Frequency Division Multiple Access) Technology (ie, frequency domain multiple access) and Interleaved-Division Multiple Access (IDMA) technology (ie, code division multiple access). Parallel multi-user data transmission can be divided into two cases. One is that multiple secondary nodes send data to the primary node at the same time, which is called uplink multi-user transmission, and the other is that the primary node sends data to multiple secondary nodes at the same time, called Downlink multi-user transmission.

When transmitting by downlink OFDMA technology, the AP will transmit data of different stations in different frequency bands, but how to properly allocate frequency bands to different users to obtain the best spectrum utilization is an important problem. The usual solution is that the AP transmits a measurement signal in the full frequency band. The station participating in the OFDMA measures the current channel based on the measurement signal, and then replies to the AP in a preset order, or waits for the AP to schedule and then replies to the AP to inform the AP which frequency bands are available. Under such a scheme, the reply information of multiple sites is time-divided, and the efficiency is low, and the site that first responds to the AP needs to wait for the last site to reply before receiving the downlink data sent by the AP. In the waiting time, due to the AP. There is no interaction with the waiting station, that is, the channel is not always occupied. Under the contention-based channel access mechanism, the channel is preempted by other stations, and when the AP sends downlink data, the channel around the waiting station has changed. , causing the measurement feedback information to be invalid.

Summary of the invention

In order to solve the existing technical problems, embodiments of the present invention are expected to provide a downlink multi-user transmission method and apparatus.

The embodiment of the invention provides a downlink multi-user transmission method, and the method includes:

The station participating in the downlink multi-user transmission adjusts the uplink transmission time of the radio frame to the access point AP, so that the radio frame sent by the station can reach the AP within the allowed time error;

Sending, by the station, a radio frame to the AP according to the uplink sending time;

The wireless frame sent by each station includes a first part of content and a second part of content, the first part of content includes information identifiable by a traditional site, and the second part of content includes information of each site.

In the above solution, the station transmits a radio frame on all of its available subchannels.

In the above solution, the first part of the content included in the radio frame sent by each station participating in the downlink multi-user transmission carries exactly the same information.

In the above solution, the first part of the content includes: a traditional short training sequence domain L-STF, a traditional long training sequence domain L-LTF, and a traditional signaling domain L-SIG.

In the above solution, the L-SIG carries frame length indication information, and the frame length indication information is used to indicate the length of the first part of the content.

In the above solution, the first part of the content further includes a traditional data domain.

In the foregoing solution, the data field includes: frame type indication information, sender address information, receiver address information, and Duration sub-domain information;

The frame type information indicates a frame type that is recognized by the traditional device, or a new frame type indication information, where the sender address information indicates preset address information, and the receiver address information indicates address information of the AP. The Duration subfield indicates a channel reservation time.

In the above solution, the second part of the content of each user is only carried on a part of subcarriers of the used subchannel, and part of the subcarriers used by each station are pre-allocated.

In the above solution, the information carried by the second part of the content indicates the frequency band resources available to the station.

In the above solution, the information carried by the second part of the content indicates channel quality information of the available frequency band resource, and the channel quality is a signal to noise ratio, or a signal to interference and noise ratio, or a modulation and coding scheme index.

In the above solution, the second part of the content is an orthogonal code pre-assigned to the station participating in the downlink multi-user transmission.

The embodiment of the present invention further provides a downlink multi-user transmission apparatus, which is applied to a site participating in downlink multi-user transmission, where the apparatus includes:

a time adjustment unit, configured to adjust an uplink transmission time of the wireless frame transmitted by the station participating in the downlink multi-user transmission to the access point AP, so that the wireless frame sent by the station can reach the AP within an allowed time error;

a sending unit, configured to send a radio frame to the AP according to the uplink sending time;

The wireless frame sent by each station includes a first partial content and a second partial content, the first partial content includes information identifiable by a traditional site, and the second partial content includes each The respective information of each site.

In the above solution, the sending unit is further configured to send a radio frame on all available subchannels of the station.

In the above solution, the second part of the content only occupies part of the subcarriers of the used subchannel, and part of the subcarriers used by each station are pre-allocated.

The time adjustment unit and the sending unit may adopt central processing when performing processing (CPU, Central Processing Unit), digital signal processor (DSP, Digital Singnal Processor) or Programmable Array (FPGA).

The downlink multi-user transmission method and device provided by the embodiment of the present invention, the station participating in the downlink multi-user transmission adjusts the uplink sending time to send a radio frame to the AP, so that the radio frame sent by the station can be allowed in the allowed time. Within the error, the AP arrives at the AP. The radio frame sent by each station contains two parts. The first part is the information that the traditional station can recognize, and the second part contains the information of the station. Therefore, all the stations participating in the downlink receiving can simultaneously reply to the AP with available channel resources, reduce the feedback overhead, and improve the transmission efficiency; the traditional station that is listening can also identify the part of the radio frame sent by the station participating in the downlink receiving, and after the solution is resolved, To compatibility issues.

DRAWINGS

1 is a schematic structural diagram of a basic service set in the prior art;

2 is a flowchart of a downlink multi-user transmission method according to Embodiment 1 of the present invention;

3 is a schematic structural diagram of a downlink multi-user transmission apparatus according to Embodiment 2 of the present invention;

4 is a schematic diagram 1 of each station in a radio frame transmission time according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a frame of a STA1 in a frequency domain and a time domain according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of a frame structure of a STA2 in a frequency domain and a time domain according to an embodiment of the present invention;

FIG. 7 is a second schematic diagram of each station in a radio frame transmission time according to an embodiment of the present invention; FIG.

FIG. 8 is a schematic diagram of a frame structure of another STA1 in a frequency domain and a time domain according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a frame structure of another STA2 in a frequency domain and a time domain according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a frame structure of another STA1 in a frequency domain and a time domain according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a frame structure of another STA2 in a frequency domain and a time domain according to an embodiment of the present invention.

detailed description

The technical solutions of the present invention are further elaborated below in conjunction with the accompanying drawings and specific embodiments.

Embodiment 1

A downlink multi-user transmission method is provided in the first embodiment of the present invention. As shown in FIG. 2, the method mainly includes:

Step 201: The station participating in the downlink multi-user transmission adjusts the uplink transmission time of the radio frame sent to the AP, so that the radio frame sent by the station can reach the AP within the allowed time error.

A station that is farther away from the AP is compared to a station that is closer to the AP, and the radio frame is transmitted in advance, and the advance amount is measured in advance by the AP and the station.

Step 202: The station sends a radio frame to the AP according to the uplink sending time. The radio frame sent by each station includes a first part of content and a second part of content, where the first part of content includes a identifiable Information, the second part of the content includes the respective information of each site.

Wherein the station transmits a radio frame on all of its available subchannels.

The first part of the content included in the radio frame sent by each station participating in the downlink multi-user transmission carries exactly the same information.

The first part of the content includes: a traditional short training sequence domain (L-STF), a traditional long training sequence domain (L-LTF), and a traditional signaling domain (L-SIG).

The L-SIG carries frame length indication information, and the frame length indication information is used to indicate the length of the first partial content.

The first part of the content further includes a traditional data domain; the data domain includes: frame type indication information, sender address information, receiver address information, and Duration sub-domain information, wherein the frame type information indicates traditional device identification. a frame type, or a new frame type indication information, the sender address information indicating preset address information, the receiver address information indicating address information of the AP, and the Duration subfield indicating a channel reservation time.

The second part of the content only occupies part of the subcarriers of the used subchannel, and part of the subcarriers used by each station are pre-allocated.

The information carried by the second part of the content indicates the frequency band resources available to the station.

The information carried by the second part of the content further indicates channel quality information of the available frequency band resource, where the channel quality is a signal to noise ratio, or a signal to interference and noise ratio, or a modulation and coding scheme index.

The second part of the content may also be an orthogonal code pre-assigned to the station participating in the downlink multi-user transmission.

Embodiment 2

Corresponding to the downlink multi-user transmission method according to the first embodiment, the second embodiment of the present invention further provides a downlink multi-user transmission apparatus, which is applied to a station participating in downlink multi-user transmission, as shown in FIG. 3, the apparatus includes :

The time adjustment unit 10 is configured to adjust an uplink transmission time of the radio frame transmitted by the station participating in the downlink multi-user transmission to the AP, so that the radio frame sent by the station can reach the AP within an allowed time error;

The transmitting unit 20 is further configured to transmit a radio frame on all available subchannels of the station.

The first part of the content includes: L-STF, L-LTF, and L-SIG.

The first part of the content also includes a conventional data field.

The data domain includes: frame type indication information, sender address information, receiver address information, and Duration subdomain information;

The frame type information indicates a frame type that is recognized by the conventional device, or new frame type indication information, the sender address information indicates preset address information, and the receiver address information indicates address information of the AP, The Duration subfield indicates the channel reservation time.

The information carried by the second part of the content may also indicate channel quality information of the available frequency band resource, where the channel quality is a signal to noise ratio, or a signal to interference and noise ratio, or a modulation and coding scheme index.

With the above embodiment of the present invention, the station participating in the downlink multi-user transmission adjusts the uplink transmission time to send a radio frame to the AP, so that the radio frame sent by the station can reach the AP within an allowable time error, and each station sends The wireless frames contain two parts, the first part is the information that the traditional site can recognize, and the second part contains the information of the site. Therefore, all the stations participating in the downlink receiving can simultaneously reply to the AP with available channel resources, reduce the feedback overhead, and improve the transmission efficiency; the traditional station that is listening can also identify the part of the radio frame sent by the station participating in the downlink receiving, and after the solution is resolved, To compatibility issues.

The above downlink multi-user transmission method and apparatus are further elaborated below in conjunction with specific examples.

Embodiment 3

Within a basic service set, it is assumed that there are 1 AP and 5 sites (identified as STA1, STA2, STA3, STA4, and STA5, respectively), and the AP and STA1, STA2, STA3, and STA4 sites All are devices conforming to the IEEE802.11ax standard; STA5 is a legacy device, and the so-called conventional device may be a device conforming to the IEEE802.11a/g/n/ac standard. It is assumed that the AP and the four 11ax stations (STA1, STA2, STA3, and STA4) support 80MHz bandwidth transmission and reception, and the AP schedules STA1, STA2, STA3, and STA4 for downlink multi-user OFDMA transmission, and the minimum frequency scheduling granularity is 20MHz. In the current WLAN standard, 20MHz is a basic subchannel bandwidth, and the scheduling granularity of 20MHz is equivalent to subchannel level scheduling. The available bandwidth includes four schedulable 20MHz bandwidths; it is assumed that the first 20MHz bandwidth is called the primary channel or the first sub-band. The remaining 20 MHz subchannels are referred to as a second subchannel, a third subchannel, and a fourth subchannel, respectively.

The AP transmits a radio frame on the 80 MHz bandwidth. The radio frame is constructed using a 20 MHz frame format and is transmitted in a repeating pattern on each 20 MHz bandwidth over the 80 MHz bandwidth, ie, the same and complete information is carried on each 20 MHz bandwidth.

After receiving the radio frame, STA1, STA2, STA3, and STA4 construct a feedback radio frame according to the current receiving situation; the subcarriers used by STA1, STA2, STA3, and STA4 in the second part of the radio frame are pre-assigned, respectively. The subcarrier sets SC1, SC2, SC3, and SC4 are used (the number of subcarrier sets may be predefined, or may be divided according to a predetermined rule according to the current scheduled number of users), and the collection of 4 subcarrier sets is a 20 MHz sub All subcarriers or subsets of subcarriers on the channel.

STA1 detects that the channel condition around itself is only available for the first subchannel, that is, the primary 20MHz subchannel is available, thereby constructing a radio frame on the subchannel, and its frame structure is as shown in FIG. 5, and the first part of the radio frame includes L- STF (traditional short training sequence domain), L-LTF (traditional long training sequence domain) and L-SIG (traditional signaling domain); among them, length subfield and rate subfield filling in L-SIG The same information of other stations, the two information comprehensively indicate that the end of the radio frame ends at the L-SIG; the second part of the radio frame, that is, only carries the information on the subcarrier indicated by the subcarrier set SC1, and the carried information is a predefined signal, the remaining subcarriers do not carry information; STA1 transmits no on the first subchannel (ie, the primary 20MHz subchannel) within a specified time Line frame.

STA2 detects that the channel conditions around itself have the first subchannel and the second subchannel available, thereby constructing a radio frame on the two subchannels, and its frame structure is as shown in FIG. 6, and the radio frames on the two subchannels are carried. The information is consistent; the first part of the radio frame contains three parts: L-STF, L-LTF and L-SIG; wherein the length subfield and rate subfield in the L-SIG fill in the same information as the other stations, the two The information comprehensive indication indicates that the end of the radio frame ends at the L-SIG; the second part of the radio frame, that is, the information is carried only on the subcarrier indicated by the subcarrier set SC2, and the carried information is a predefined signal, and the remaining subcarriers The information is not carried; STA2 transmits a radio frame on the first subchannel and the second subchannel within a prescribed time, and the two subchannels carry exactly the same information.

STA3 detects that the channel condition around itself has a third subchannel available, thereby constructing a radio frame on the subchannel, and the first part of the radio frame includes three parts: L-STF, L-LTF and L-SIG; - The length subfield and rate subfield in the SIG fill in the same information as the other stations. These two information comprehensively indicate that the end of the radio frame ends at the L-SIG; the second part of the radio frame, that is, only the subcarrier set The information carried on the subcarrier indicated by SC3 carries the information, the carried information is a predefined signal, and the remaining subcarriers do not carry the information; STA3 transmits the radio frame on the third subchannel within a specified time.

STA4 detects that there are no subchannels available for the channel conditions around itself, so that no radio frames are formed.

After the station participating in the downlink multi-user OFDMA transmission transmits the above-mentioned radio frame, the three radio frames (that is, the radio frames transmitted by STA1, STA2, and STA3) can reach the AP simultaneously or approximately simultaneously within the range allowed by the synchronization error, and the AP is superimposed according to the superposition. The second part of the radio frame together can obtain the subchannels currently available to each station participating in the downlink multi-user OFDMA transmission by analyzing the respective subcarrier sets on different subchannels; for example, the subcarriers of the AP in the first subchannel Pre-defined information is detected on the set SC1 and SC2, that is, the first sub-channel in the surrounding wireless environment of STA1 and STA2 is known to be available, and the sub-carrier sets SC3 and SC4 in the first sub-channel are obtained. If the predefined information is not detected, it can be known that the first subchannel in the surrounding wireless environment of STA3 and STA4 is unavailable; the AP detects the predefined information in the subcarrier set SC2 of the second subchannel, that is, the surrounding STA2 is known. The second subchannel in the wireless environment is available; the predefined information is not detected on the subcarrier sets SC1, SC3, and SC4 of the second subchannel, and the second sub of the surrounding wireless environments of STA1, STA3, and STA4 is known. The channel is not available; and so on, the AP can learn that only STA3 can use the third subchannel, and no station can use the fourth subchannel.

The conventional device STA5 receives any one of the radio frames or multiple radio frames transmitted by the three 11ax devices, and can identify the first portion, and learns that the radio frame ends at the L-SIG through the L-SIG in the first portion, thereby no longer Further receive the second part of the follow-up.

In this embodiment, a schematic diagram of each station STA1, STA2, and STA3 in the radio frame transmission time is shown in FIG. 4, and each station adjusts the uplink transmission time of the radio frame to the AP, so that the radio frame transmitted by each station can be The allowed time error arrives at the AP simultaneously or approximately simultaneously.

Embodiment 4

Within a basic service set, it is assumed that there are 1 AP and 5 sites (identified as STA1, STA2, STA3, STA4, and STA5, respectively), and the AP and STA1, STA2, STA3, and STA4 sites are all in compliance with the IEEE802.11ax standard. The device; STA5 is a conventional device, and the so-called conventional device may be a device conforming to the IEEE802.11a/g/n/ac standard. It is assumed that the AP and the four 11ax stations (STA1, STA2, STA3, and STA4) support 80MHz bandwidth transmission and reception, and the AP schedules STA1, STA2, STA3, and STA4 for downlink multi-user OFDMA transmission, and the minimum frequency scheduling granularity is 20MHz. In the current WLAN standard, 20MHz is a basic subchannel bandwidth, and the scheduling granularity of 20MHz is equivalent to subchannel level scheduling. The available bandwidth includes four schedulable 20MHz bandwidths; it is assumed that the first 20MHz bandwidth is called the primary channel or the first sub-band. The channel, the remaining 20 MHz subchannels, are referred to as a second subchannel, a third subchannel, and a fourth subchannel, respectively.

The AP transmits a radio frame on the 80 MHz bandwidth, and the radio frame uses the 20 MHz frame format group. Built in a repeating pattern on each 20 MHz bandwidth over the 80 MHz bandwidth, ie carrying the same and complete information on every 20 MHz bandwidth.

STA1 detects that the channel condition around itself is only available for the first subchannel, that is, the primary 20MHz subchannel is available, thereby constructing a radio frame on the subchannel, and its frame structure is as shown in FIG. 8, and the first part of the radio frame includes L- STF, L-LTF, L-SIG, and data field (DATA); among them, the length subfield and rate subfield in the L-SIG fill in the same information as other sites, and these two information comprehensively indicate the wireless The frame end time ends in the data field of the first part, and the rate sub-field indicates the modulation and coding mode adopted by the first part of the data field; the data field part includes at least the frame type indication information, the sender address information, the receiver address information, and the Duration sub-domain information. The frame type information may be a frame type recognized by the conventional device or a new frame type indication information, the sender address information is filled in a preset address information, the receiver address information is filled in the AP address, and the Duration subfield indicates a The channel reservation time, the data domain part also carries the same information as other sites to ensure that each station transmits the first part of the radio frame. The same information. The second part of the radio frame, that is, the information is carried only on the subcarrier indicated by the subcarrier set SC1, and the bearer information is the channel quality information of the first subchannel measured by STA1, and the channel quality information may specifically be the channel signal to noise ratio. Or the signal to interference and noise ratio, or modulation coding index, etc., the remaining subcarriers do not carry information; STA1 transmits the radio frame on the first subchannel within a prescribed time.

STA2 detects that the channel conditions around itself have the first subchannel and the second subchannel available, thereby forming a radio frame on the two subchannels, and the first part of the radio frame on the two subchannels The information contained in the second part carries the channel quality information of the respective subchannels, and its frame structure is as shown in FIG. 9. The first part of the radio frame includes the four parts of L-STF, L-LTF, L-SIG and data domain. The length subfield and the rate subfield in the L-SIG fill in the same information as other stations, and the two information comprehensively indicate that the end of the radio frame ends in the first part of the data field, and the rate subfield indicates the first part of the data field. The modulation and coding mode adopted; the data domain part at least includes frame type indication information, sender address information, receiver address information, and Duration subdomain information, wherein the frame type information may be a frame type recognized by a conventional device or may be a new one. The frame type indication information, the sender address information fills in a preset address information, the receiver address information fills in the AP address, the Duration subdomain indicates a channel reservation time, and the data domain part also carries the same information as other sites to ensure each The first part of the station transmitting the radio frame carries the same information. The second part of the radio frame, that is, the information is carried only on the subcarrier indicated by the subcarrier set SC2, and the bearer information is the channel quality information of the first subchannel and the second subchannel measured by the STA2, and the channel quality information may specifically be Channel signal to noise ratio, or signal to interference and noise ratio, or modulation coding index, etc.; STA2 transmits a radio frame on the first subchannel and the second subchannel within a prescribed time.

STA3 detects that the channel condition around itself has a third subchannel available, thereby constructing a radio frame on the subchannel, and the first part of the radio frame includes the four parts of L-STF, L-LTF, L-SIG and data domain, wherein The length subfield and the rate subfield in the L-SIG fill in the same information as the other stations. The two information comprehensively indicate that the end of the radio frame ends in the first part of the data field, and the rate subfield indicates that the first part of the data field is used. Modulation coding mode; the data domain part at least includes frame type indication information, sender address information, receiver address information, and Duration subdomain information, wherein the frame type information may be a frame type recognized by a conventional device or a new frame Type indication information, the sender address information fills in a preset address information, the receiver address information fills in the AP address, the Duration subdomain indicates a channel reservation time, and the data domain part also carries the same information as other sites to ensure each site. The first part of the transmitted radio frame carries the same information; the second part of the radio frame, ie only the subcarrier set SC3 Bearer on a subcarrier illustrated The information carried by the STA3 is the channel quality information of the third subchannel measured by STA3, and the channel quality information may specifically be a channel signal to noise ratio, a signal to interference and noise ratio, or a modulation and coding index, and the remaining subcarriers do not carry information; STA3 The radio frame is transmitted on the third subchannel within a prescribed time.

After the station participating in the downlink multi-user OFDMA transmission transmits the above-mentioned radio frame, the three radio frames (ie, the radio frames transmitted by STA1, STA2, and STA3) can reach the AP simultaneously or approximately simultaneously within the range allowed by the synchronization error, and the AP is superimposed according to The second part of the radio frame together can obtain the subchannels currently available and the channel quality of each station participating in the downlink multi-user OFDMA transmission by analyzing each subcarrier set on different subchannels; for example, the AP is in the first subchannel. The pre-defined information is detected on the sub-carrier sets SC1 and SC2, that is, the first sub-channel in the surrounding radio environment of STA1 and STA2 is available and the corresponding channel quality is obtained, and the sub-carrier sets SC3 and SC4 of the first sub-channel are not When the predefined information is detected, it can be known that the first subchannel in the surrounding wireless environment of STA3 and STA4 is unavailable; the AP detects the predefined information in the subcarrier set SC2 of the second subchannel, that is, the wireless environment around the STA2 is known. The second subchannel in the available and the corresponding channel quality; no predefined ones are detected on the subcarrier sets SC1, SC3 and SC4 of the second subchannel It can be known that the second subchannel in the surrounding wireless environment of STA1, STA3, and STA4 is unavailable; and so on, the AP can learn that only STA3 can use the third subchannel and the corresponding channel quality, and no station can use the fourth. Subchannel.

The conventional device STA5 receives any one of the radio frames or multiple radio frames transmitted by the three 11ax devices, and can identify the first portion, and learns the length of the radio frame through the L-SIG in the first portion, and completes the radio frame reception according to the length. (Only the first part of the radio frame is received), the channel reservation time can be known by parsing the Duration in the first part of the data field.

In this embodiment, a schematic diagram of each station STA1, STA2, and STA3 in the radio frame transmission time is shown in FIG. 7. Each station adjusts the uplink transmission time of the radio frame to the AP, so that the radio frame sent by each station can be Simultaneous or near simultaneous arrival within the allowed time error AP.

Embodiment 5

Within a basic service set, it is assumed that there are 1 AP and 5 sites (identified as STA1, STA2, STA3, STA4, and STA5, respectively), and the AP and STA1, STA2, STA3, and STA4 sites are all in compliance with the IEEE802.11ax standard. The device; STA5 is a conventional device, and the so-called conventional device may be a device conforming to the IEEE802.11a/g/n/ac standard. It is assumed that the AP and the four 11ax stations (STA1, STA2, STA3, and STA4) support 80MHz bandwidth transmission and reception, and the AP schedules STA1, STA2, STA3, and STA4 for downlink multi-user OFDMA transmission, and the minimum frequency scheduling granularity is 20MHz. In the current WLAN standard, 20MHz is a basic subchannel bandwidth, and the scheduling granularity of 20MHz is equivalent to subchannel level scheduling. The available bandwidth includes four schedulable 20MHz bandwidths, assuming that the first 20MHz bandwidth is called the primary channel or the first sub-band. The remaining 20 MHz subchannels are referred to as a second subchannel, a third subchannel, and a fourth subchannel, respectively.

After receiving the foregoing radio frame, the STA1, the STA2, the STA3, and the STA4 construct a feedback radio frame according to the current receiving situation; the codes used by the STA1, STA2, STA3, and STA4 in the second part of the radio frame are pre-defined, and the code carriers are mutually Orthogonal or quasi-orthogonal.

STA1 detects that the channel condition around itself is only available for the first subchannel, that is, the primary 20MHz subchannel is available, thereby constructing a radio frame on the subchannel, and its frame structure is as shown in FIG. 10, and the first part of the radio frame includes L- The three parts of STF, L-LTF and L-SIG, in which the length subfield and rate subfield in the L-SIG fill in the same information as other stations, and the two information comprehensively indicate that the end of the radio frame is at L - SIG ends; the second part of the radio frame, the carried information is a pre-allocated orthogonal code; STA1 transmits the radio frame on the first subchannel within a prescribed time.

STA2 detects that the channel conditions around itself have the first subchannel and the second subchannel. To form a radio frame on the two subchannels, the frame structure is as shown in FIG. 11, the information carried by the radio frames on the two subchannels is consistent; the first part of the radio frame includes L-STF, L-LTF and L- The SIG is a three-part process in which the length subfield and the rate subfield in the L-SIG fill in the same information as other stations, and the two information comprehensively indicate that the end of the radio frame ends at the L-SIG; In the second part, the carried information is a pre-allocated orthogonal code, and the codes on the first subchannel and the second subchannel are the same; STA2 transmits the radio frame on the first subchannel and the second subchannel within a prescribed time. The two subchannels carry exactly the same information.

STA3 detects that the channel condition around itself has a third subchannel available, thereby constructing a radio frame on the subchannel, and the first part of the radio frame includes three parts: L-STF, L-LTF and L-SIG, wherein, in L - The length subfield and rate subfield in the SIG fill in the same information as the other stations. These two information comprehensively indicate that the end of the radio frame ends at the L-SIG; the second part of the radio frame, that is, only the subcarrier set The information carried on the subcarrier indicated by SC3 carries the information, and the carried information is a predefined code; STA3 transmits the radio frame on the third subchannel within a prescribed time.

After the station participating in the downlink multi-user OFDMA transmission transmits the above-mentioned radio frame, the three radio frames (ie, the radio frames transmitted by STA1, STA2, and STA3) can reach the AP simultaneously or approximately simultaneously within the range allowed by the synchronization error, and the AP is superimposed according to In the second part of the radio frame together, by analyzing the orthogonal code on different subchannels, the subchannels currently available to each station participating in the downlink OFDMA transmission can be known; for example, the AP detects the allocation to the STA1 on the first subchannel. The code and the code of STA2, that is, the first subchannel in the surrounding wireless environment of STA1 and STA2 are known to be available; if the code assigned to STA3 and STA4 is not detected on the first subchannel, the respective surroundings of STA3 and STA4 can be known. The first subchannel in the wireless environment is unavailable; the AP detects the code assigned to STA2 on the second subchannel, that is, the second subchannel in the wireless environment around STA2 is available; no allocation is detected on the second subchannel. For the codes of STA1, STA3, and STA4, it can be known that the second subchannel in the surrounding wireless environment of STA1, STA3, and STA4 is not Available; and so on, the AP can learn that only STA3 can use the third subchannel, and no station can use the fourth subchannel.

The conventional device STA5 receives any one of the radio frames or multiple radio frames transmitted by the three 11ax devices, and can identify the first portion, and learns that the radio frame ends at the L-SIG through the L-SIG in the first portion, and no further Receive the second part of the follow-up.

Embodiment 6

Within a basic service set, it is assumed that there are 1 AP and 5 sites (identified as STA1, STA2, STA3, STA4, and STA5, respectively), and the AP and STA1, STA2, STA3, and STA4 sites are all in compliance with the IEEE802.11ax standard. The device; STA5 is a conventional device, and the so-called conventional device may be a device conforming to the IEEE802.11a/g/n/ac standard. Assume that the AP and the four 11ax sites (STA1, STA2, STA3, and STA4) support 80MHz bandwidth transmission and reception. The AP schedules STA1, STA2, STA3, and STA4 for downlink multi-user OFDMA transmission. The minimum frequency granularity of the frequency domain is n MHz. Each subchannel can be divided into N subbands. In the current WLAN standard, 20MHz is a basic subchannel bandwidth; assuming that the available channel bandwidth of the system is 80MHz, the first 20MHz bandwidth is called the primary channel or the first subchannel, and the remaining 20MHz subchannels are called the second subchannel, The third subchannel and the fourth subchannel.

STA1 detects that the channel condition around itself is only available for the first subchannel, that is, the primary 20MHz subchannel is available, thereby constructing a radio frame on the subchannel, and the first part of the radio frame includes L-STF, L-LTF, and L-SIG. And the data field are four parts; wherein the length subfield and the rate subfield in the L-SIG fill in the same information as the other stations, and the two information comprehensively indicate that the end time of the radio frame ends in the first part of the data field, the rate The sub-domain indicates a modulation and coding mode adopted by the first part of the data field; the data field part includes at least frame type indication information, sender address information, receiver address information, and Duration sub-domain information, where the frame type information may be a frame recognized by the conventional device. The type can also be a new frame type indication information, the sender address information fills in a preset address information, the receiver address information fills in the AP address, the Duration subdomain indicates a channel reservation time, and the data domain part is also fully loaded with other sites. The same information to ensure that the first part of the wireless frame transmitted by each station carries the same information; the second part of the wireless frame That is, the information is carried only on the subcarrier indicated by the subcarrier set SC1, and the bearer information is the channel quality information of each subband on the first subchannel measured by STA1, or the index indication of the x subbands with the best channel quality. And the corresponding subband channel quality information, the channel quality information may specifically be a channel signal to noise ratio, or a signal to interference and noise ratio, or a modulation and coding index, etc., and the remaining subcarriers do not carry information; STA1 is on the first subchannel within a prescribed time. Send a wireless frame.

STA2 detects that the channel conditions around itself have the first subchannel and the second subchannel available, so that radio frames are formed on the two subchannels, and the information carried in the first part of the radio frames on the two subchannels is consistent, and the second part carries Channel quality information of the respective subchannels; the first part of the radio frame includes four parts of L-STF, L-LTF, L-SIG, and data domain, wherein the length subfield and rate subfield in the L-SIG are filled in with other The same information of the station, the two information comprehensively indicate that the end time of the radio frame ends in the first part of the data field, and the rate sub-field indicates the modulation and coding mode adopted by the first part of the data field, and the data field part at least includes the frame type indication information and the sender. Address information, receiver address information, and Duration sub-domain information, where the frame type information may be a frame type recognized by a conventional device or a new frame type indication information, a sender address letter Fill in a preset address information, the recipient address information fills in the AP address, the Duration subdomain indicates a channel reservation time, and the data domain part also carries the same information as other sites to ensure that each station transmits the first part of the radio frame. The same information; the second part of the radio frame, that is, the information is carried only on the subcarrier indicated by the subcarrier set SC2, and the bearer information is the channel quality information of each subband on the first subchannel and the second subchannel measured by STA2. Or the index indication of the x subbands with the best channel quality and the corresponding subband channel quality information, and the channel quality information may specifically be a channel signal to noise ratio, or a signal to interference and noise ratio, or a modulation and coding index, etc., STA2 is specified. The radio frame is transmitted on the first subchannel and the second subchannel within the time.

STA3 detects that the channel condition around itself has a third subchannel available, thereby constructing a radio frame on the subchannel, and the first part of the radio frame includes the four parts of L-STF, L-LTF, L-SIG and data domain, wherein The length subfield and the rate subfield in the L-SIG fill in the same information as the other stations. The two information comprehensively indicate that the end of the radio frame ends in the first part of the data field, and the rate subfield indicates that the first part of the data field is used. The modulation and coding mode, the data domain part at least includes frame type indication information, sender address information, receiver address information, and Duration sub-domain information, where the frame type information may be a frame type recognized by a conventional device or a new frame. Type indication information, the sender address information fills in a preset address information, the receiver address information fills in the AP address, the Duration subdomain indicates a channel reservation time, and the data domain part also carries the same information as other sites to ensure each site. The first part of the transmitted radio frame carries the same information; the second part of the radio frame, ie only the subcarrier set SC3 Carrying information on the subcarriers, the information carried is the channel quality information of each subband of the third subchannel measured by STA3, or the index indication of the x subbands with the best channel quality and the corresponding subband channel quality. The information, the channel quality information may be a channel signal to noise ratio, or a signal to interference and noise ratio, or a modulation and coding index, etc., and the remaining subcarriers do not carry information; STA3 transmits a radio frame on the third subchannel within a prescribed time.

After the station participating in the downlink multi-user OFDMA transmission transmits the above-mentioned radio frame, the three radio frames (ie, the radio frames transmitted by STA1, STA2, and STA3) can reach the AP simultaneously or approximately simultaneously within the range allowed by the synchronization error, and the AP is superimposed according to The second part of the radio frame together can obtain the channel quality of each sub-band or partial sub-band on the currently available sub-channels of each station participating in the downlink multi-user OFDMA transmission by analyzing each sub-carrier set on different sub-channels; for example; The AP detects bearer information on the subcarrier sets SC1 and SC2 of the first subchannel, that is, learns the channel quality of each subband or the best x subbands on the first subchannel in the surrounding radio environment of STA1 and STA2. If the predefined information is not detected on the subcarrier sets SC3 and SC4 of the first subchannel, it can be known that the first subchannel in the surrounding wireless environment of STA3 and STA4 is unavailable; the subcarrier of the AP in the second subchannel The set SC2 detects that there is bearer information, that is, the channel quality of each subband or the best x subbands on the second subchannel in the radio environment around STA2 is known; in the second subchannel If the predefined information is not detected on the subcarrier sets SC1, SC3, and SC4, it can be known that the second subchannel in the surrounding wireless environment of STA1, STA3, and STA4 is unavailable; and so on, the AP can learn that STA3 is in the third sub The channel quality of each subband or the best x subbands on the channel, STA2, STA1 and STA4 do not use the third subchannel, and no station can use the fourth subchannel.

In summary, in the embodiment of the present invention, the station participating in the downlink multi-user transmission adjusts the uplink sending time to send a radio frame to the AP, so that the radio frame sent by the station can reach the AP within an allowable time error. The wireless frames sent by the stations contain two parts of content. The first part is the information that the traditional site can recognize, and the second part contains the information of the respective sites. Therefore, all stations participating in downlink reception can simultaneously reply to the AP with available channel resources, reducing the reverse Feeding overhead, improve transmission efficiency; the traditional site of the listening can also identify the wireless frame part information sent by the stations participating in the downlink reception, and solve the backward compatibility problem.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention can take the form of a hardware embodiment, a software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Range of protection.

Industrial applicability

Claims

A downlink multi-user transmission method, the method comprising:

The station participating in the downlink multi-user transmission adjusts the uplink transmission time of the radio frame to the access point AP, so that the radio frame sent by the station can reach the AP within the allowed time error;

Sending, by the station, a radio frame to the AP according to the uplink sending time;

The wireless frame sent by each station includes a first part of content and a second part of content, the first part of content includes information identifiable by a traditional site, and the second part of content includes information of each site.
The downlink multi-user transmission method according to claim 1, wherein said station transmits a radio frame on all of its available subchannels.
The downlink multi-user transmission method according to claim 1, wherein the first part of the content included in the radio frame transmitted by each station participating in the downlink multi-user transmission carries exactly the same information.
The downlink multi-user transmission method according to claim 3, wherein the first partial content comprises: a conventional short training sequence domain L-STF, a conventional long training sequence domain L-LTF, and a conventional signaling domain L-SIG.
The downlink multi-user transmission method according to claim 4, wherein the L-SIG carries frame length indication information, and the frame length indication information is used to indicate a length of the first partial content.
The downlink multi-user transmission method according to claim 3, wherein said first partial content further comprises a conventional data domain.
The downlink multi-user transmission method according to claim 6, wherein the data domain comprises: frame type indication information, sender address information, receiver address information, and Duration sub-domain information;

The frame type information indicates a frame type recognized by the traditional device, or new frame type indication information, where the sender address information indicates preset address information, and the receiver address information The information indicates the address information of the AP, and the Duration subfield indicates the channel reservation time.
The downlink multi-user transmission method according to any one of claims 2 to 7, wherein the second partial content of each user is carried only on a part of subcarriers of the used subchannel, and a part of subcarriers used by each station It is pre-allocated.
The downlink multi-user transmission method according to claim 8, wherein the information carried by the second partial content indicates a frequency band resource available to the station.
The downlink multi-user transmission method according to claim 8, wherein the information carried by the second partial content indicates channel quality information of the available frequency band resource, the channel quality being a signal to noise ratio, or a signal to interference and noise ratio, or Modulation coding scheme index.
The downlink multi-user transmission method according to claim 1, wherein the second partial content is an orthogonal code pre-allocated to the station participating in the downlink multi-user transmission.
A downlink multi-user transmission apparatus is applied to a station participating in downlink multi-user transmission, and the apparatus includes:

a time adjustment unit, configured to adjust an uplink transmission time of the wireless frame transmitted by the station participating in the downlink multi-user transmission to the access point AP, so that the wireless frame sent by the station can reach the AP within an allowed time error;

a sending unit, configured to send a radio frame to the AP according to the uplink sending time;

The wireless frame sent by each station includes a first part of content and a second part of content, the first part of content includes information identifiable by a traditional site, and the second part of content includes information of each site.
The downlink multi-user transmission apparatus according to claim 12, wherein said transmitting unit is further configured to transmit a radio frame on all available subchannels of the station.
The downlink multi-user transmission apparatus according to claim 12, wherein the first part of the content included in the radio frame transmitted by each station participating in the downlink multi-user transmission carries exactly the same information.
The downlink multi-user transmission apparatus according to claim 14, wherein said first partial content comprises: a conventional short training sequence domain L-STF, a conventional long training sequence domain L-LTF, and a conventional signaling domain L-SIG.
The downlink multi-user transmission apparatus according to claim 15, wherein the L-SIG carries frame length indication information, and the frame length indication information is used to indicate a length of the first partial content.
The downlink multi-user transmission apparatus according to claim 15, wherein said first partial content further comprises a conventional data domain.
The downlink multi-user transmission apparatus according to claim 17, wherein the data domain comprises: frame type indication information, sender address information, receiver address information, and Duration sub-domain information;

The frame type information indicates a frame type that is recognized by the traditional device, or a new frame type indication information, where the sender address information indicates preset address information, and the receiver address information indicates address information of the AP. The Duration subfield indicates a channel reservation time.
The downlink multi-user transmission apparatus according to any one of claims 13 to 18, wherein the second partial content occupies only a part of subcarriers of the used subchannel, and a part of the subcarriers used by each station are pre-allocated.
The downlink multi-user transmission apparatus according to claim 19, wherein the information carried by the second partial content indicates a frequency band resource available to the station.
The downlink multi-user transmission apparatus according to claim 19, wherein the information carried by the second partial content indicates channel quality information of the available frequency band resource, the channel quality being a signal to noise ratio, or a signal to interference and noise ratio, or Modulation coding scheme index.
The downlink multi-user transmission apparatus according to any one of claims 13 to 18, wherein the second partial content is an orthogonal code pre-assigned to the station participating in the downlink multi-user transmission.