WO2018161269A1

WO2018161269A1 - Contention window adjustment method and network apparatus

Info

Publication number: WO2018161269A1
Application number: PCT/CN2017/075928
Authority: WO
Inventors: 李振宇; 胡磊; 唐文芳; 李汉涛
Original assignee: 华为技术有限公司
Priority date: 2017-03-08
Filing date: 2017-03-08
Publication date: 2018-09-13

Abstract

Disclosed in the present application is a contention window adjustment method, comprising: upon receiving, from terminals in a first cell, feedback information of downlink data, the downlink data being sent during a first time period, a network apparatus computing a ratio of a confirmation message fed back by each of the terminals during the first time period to the entirety of the feedback information; determining terminals desiring to send downlink data on a first target subframe as terminals to be scheduled, and selecting, according to the computation result and from the terminals to be scheduled, a terminal meeting a communication quality requirement to be a first target terminal; sending, on the first target subframe, first downlink data to first scheduling terminals including the first target terminal; and configuring, according to feedback information of the first scheduling terminals for the first downlink data, a contention window for the next data transmission operation. Also provided in the present application is a network apparatus implementing the above method. The present application reduces the size of a contention window, and improves a channel utilization rate.

Description

Method and network device for adjusting competition window

Technical field

The present application relates to the field of wireless communications, and in particular, to a method and network device for adjusting a contention window.

Background technique

Listening to Talk (LBT) is a mechanism for solving channel conflicts proposed by the 3rd Generation Partnership Project (3GPP). Clear Channel Assessment (CCA) is a carrier detection technique applied to a wireless communication system to detect whether a channel is idle. LBT requires the station to listen to the channel before using the channel. When the station wants to send data, the station randomly selects an integer from [0, CW] as the initial value of the backoff counter. Performing CCA on the current carrier. When the detection result of the CCA is that the channel is idle, the value of the backoff counter is decremented by one. When the detection result of the CCA is busy, the value of the backoff counter is suspended, and channel detection is performed during the defer period. The result of the channel detection in the delay period is that the channel is idle, and then the CCA detection is performed. When the detection result of the CCA is that the channel is idle, the backoff counter is decremented by one. When the value of the backoff counter is reduced to 0, the downlink data is transmitted.

Please refer to FIG. 1, the prior art method of adjusting the contention window as follows: a network device disposed CW = CW _min. The backoff time is selected from the CW _min , and after the network device completes the backoff according to the backoff time, the downlink data is sent to the terminal in the downlink subframe k according to the scheduling priority of the terminal. When the hybrid automatic repeat request (HARQ) feedback information corresponding to the downlink subframe k is NACK, the contention window is increased to the next level of the contention window. When the HARQ feedback information corresponding to the downlink subframe k is ACK, CW=CW _min . When CW=CW _max , CW no longer increases. The CW is the current contention window, the CW _min is the minimum contention window, and the CW _max is the maximum contention window. The downlink subframe k is the first subframe in which the station sends the downlink data last time, and the subframe needs to have valid HARQ feedback. The HARQ feedback information of the downlink subframe k is defined as NACK: 80% or more of the HARQ feedback information corresponding to the downlink subframe k is NACK.

It can be seen that when multiple terminals feed back NACK to the network device, it is easy for the network device to expand the contention window. In practical applications, channel fading or channel interference may cause the terminal to fail to receive data correctly. After continuously expanding the contention window, the contention window becomes large, and the backoff time becomes very long, resulting in low channel utilization.

Summary of the invention

The application provides a method for adjusting a contention window and a network device for narrowing the contention window and improving channel utilization.

The first aspect provides a method for adjusting a contention window, including: after receiving, by the network device, the feedback information of the downlink data sent by the terminal of the first cell to the first time period, the acknowledgment message fed back by each terminal in the first time period is counted. a ratio of all the feedback information, and determining that the terminal to send the downlink data in the first target subframe is the to-be-scheduled terminal; and then selecting, according to the statistical result, the terminal that meets the communication quality requirement from the to-be-scheduled terminal as the first target terminal, The first target subframe sends the first downlink data to the first scheduling terminal that includes the first target terminal; and sets a contention window for the next data transmission according to the feedback information of the first scheduling terminal to the first downlink data. Where the first target subframe is in the first After a period of time, a subframe for setting a contention window of the next transmission data, the first downlink data is downlink data sent to the first scheduling terminal in the first target subframe.

Therefore, the network device can determine the communication quality of the terminal according to the ratio of the acknowledgement message fed back by the terminal to the total feedback information, and then schedule the terminal that meets the communication quality requirement in the first target subframe, thereby improving the contention window to be set to The probability of the minimum contention window, which in turn reduces the backoff time before the next data transmission, thereby improving channel utilization.

In another possible implementation manner of the first aspect, the determining, by the network device, the terminal that meets the communication quality requirement from the to-be-scheduled terminal as the first target terminal may be: the network device confirms the feedback of the terminal to be scheduled. The ratio of the message to the total feedback information is sorted from large to small, and the first n terminals are determined to be terminals satisfying the communication quality requirement, and the first n terminals are used as the first target terminal. Where n is not greater than the number of network resources of the network device.

Therefore, the network device may select, according to the statistical result, a part of the terminal with the best communication quality as the first target terminal, and send the downlink data to the first scheduling terminal that includes the first target terminal in the first target subframe. After that, the feedback information corresponding to the first downlink data has the highest probability of confirming the message, and the probability of adjusting the next contention window to the minimum contention window is also the largest, so that the backoff time can be effectively shortened and the channel utilization rate can be improved.

In another possible implementation manner of the first aspect, the network device, according to the statistics, selects, from the to-be-scheduled terminal, the terminal that meets the communication quality requirement as the first target terminal, where the network device determines from the to-be-scheduled terminal. The terminal that confirms that the proportion of all the feedback information exceeds the first preset threshold is a terminal that satisfies the communication quality requirement, and all or part of the terminal that satisfies the communication quality requirement is used as the first target terminal.

Therefore, the network device can select the terminal that meets the communication quality requirement from the to-be-scheduled terminal according to the first preset threshold, and send the first downlink data to the terminal with reliable communication quality in the first target subframe instead of scheduling priority. The higher level terminal sends downlink data. Compared with the prior art, the feedback information corresponding to the first downlink data in the present application has a higher probability of confirming the message, and the probability of adjusting the next contention window to the minimum contention window is also larger, so that the backoff time can be effectively shortened. Improve channel utilization.

In another possible implementation manner of the first aspect, before the network device collects the feedback information of the downlink data sent by the terminal of the first cell to the first time period, the network device sets a lower limit of the expected scheduling duration of the first cell; The network device collects feedback information of the downlink data sent by the terminal of the first cell to the first time period to the lower limit of the expected scheduling duration in the first time period.

It can be seen that if the duration of the carrier occupied by the first cell in the first time period is less than the lower limit of the expected scheduling time, it indicates that the carrier time of the first cell is too small, and it is difficult to ensure normal service execution. The network device can schedule the terminal that meets the communication quality requirement, shorten the backoff time, and improve the opportunity for the first cell to occupy the carrier, thereby increasing the time that the first cell occupies the carrier.

Further, in another possible implementation manner of the first aspect, the determining, by the network device, the lower limit of the expected scheduling duration of the first cell may be: the average value of the data rate of the network device according to the first cell in the second time period The data transmission rate of the RLC layer entry of the cell in the second time period determines the proportion of time that the first cell expects to occupy the carrier; the network device determines, according to the idle channel estimation result of the carrier in the second time period, that the other cell occupies the carrier in the second time period. The duration, according to the duration of the occupied cells of the other cells in the second period and the duration of the second period, determining the proportion of time that the other cells expect to occupy the carrier; and then, according to the proportion of time that the first cell expects to occupy the carrier, the expected occupancy of the other cells The time ratio of the wave and the duration of the first time period determine the lower limit of the desired scheduling time of the first cell. The second time period is before the first time period, and the other cells are cells occupying carriers in the second time period except the first cell.

Therefore, the network device can measure the actual bearer of the carrier, and determine the lower limit of the expected scheduling time according to the measurement result. Therefore, the present application can adjust the lower limit of the expected scheduling time according to the actual bearer of the carrier, and provides a feasible setting of the lower limit of the desired scheduling duration. Program.

In another possible implementation manner of the first aspect, the method further includes: determining, by the network device, an upper limit of a desired scheduling duration of the first cell; and detecting that the duration of the first cell occupying the carrier in the first time period is greater than a desired scheduling duration When the upper limit is used, the network device selects, from the to-be-scheduled terminal, a terminal that does not meet the communication quality requirement as the second target terminal according to the ratio of the denied message to the total feedback information in the first time period, and includes the second target in the first target subframe. The second scheduling terminal of the terminal sends the second downlink data. Finally, according to the feedback information of the second scheduling data by the second scheduling terminal, the contention window of the next data transmission is set. The second downlink data is downlink data that is sent to the second scheduling terminal in the first target subframe.

Therefore, the network device may select, according to the foregoing statistical result, a part of the terminal with the worst communication quality from the to-be-scheduled terminal as the second target terminal, and send the downlink to the second scheduling terminal that includes the second target terminal in the first target subframe. After the data, the feedback information corresponding to the second downlink data has the highest probability of denying the message, and the probability of expanding the next contention window is also the largest, so the backoff time can be effectively increased, thereby improving the opportunity for other network devices to occupy the carrier, and achieving a fair competition channel. purpose.

Further, in another possible implementation manner of the first aspect, the determining, by the network device, the upper limit of the expected scheduling duration of the first cell may be: the average value of the data rate of the network device according to the first cell in the second time period The data transmission rate of the RLC layer entry of the cell in the second period determines the proportion of time that the first cell expects to occupy the carrier, and the second period is before the first period; the network device determines, according to the idle channel evaluation result of the carrier in the second period, The length of time that the other cells occupy the carrier in the second time period, according to the duration of the other cells occupying the carrier in the second time period and the duration of the second time period, determining the proportion of time that the other cells expect to occupy the carrier, and the other cells are in addition to the first cell. The second time period occupies the cell of the carrier; the network device determines the upper limit of the expected scheduling time of the first cell according to the proportion of time that the first cell expects to occupy the carrier, the proportion of time that the other cell expects to occupy the carrier, and the duration of the first time period.

It can be seen that the network device can measure the actual bearer of the carrier, and determine the upper limit of the expected scheduling time according to the measurement result. Therefore, the present application can adjust the expected scheduling duration upper limit according to the actual bearer of the carrier, and provides a feasible setting of the upper limit of the desired scheduling duration. Program.

The second aspect provides a network device, which can implement the function of the network device in the method for adjusting a contention window in the first aspect. This function can be implemented in hardware or in hardware by executing the corresponding software.

A third aspect provides a computer readable storage medium having instructions stored therein that, when executed on a computer, cause the computer to perform the methods described in the above aspects.

A fourth aspect provides a computer program product comprising instructions which, when executed on a computer, cause the computer to perform the methods described in the various aspects above.

It can be seen from the foregoing embodiment that the network device receives the feedback information of the downlink data sent by the terminal of the first cell to the first time period, and collects the ratio of the acknowledgement message fed back by each terminal in the first time period to the total feedback information; Determining that the terminal to send downlink data in the first target subframe is the to-be-scheduled terminal, and according to the statistical result, from the to-be-scheduled terminal Selecting a terminal that meets the communication quality requirement as the first target terminal, and then transmitting, in the first target subframe, the first downlink data to the first scheduling terminal that includes the first target terminal, and the first downlink data according to the first scheduling terminal. The feedback information sets the competition window for the next data sent. Compared with the prior art, the present application can improve the probability of setting the contention window to the minimum contention window by scheduling the terminal that satisfies the communication quality requirement in a specific subframe, thereby shortening the backoff time before the next data transmission, thereby improving Channel utilization.

DRAWINGS

1 is a schematic flow chart of a method for adjusting a contention window in the prior art;

2 is a schematic diagram of an application scenario in an embodiment of the present invention;

3 is a schematic structural diagram of a network device according to an embodiment of the present invention;

4 is a schematic flowchart of a method for adjusting a contention window according to an embodiment of the present invention;

FIG. 5 is another schematic flowchart of a method for adjusting a contention window according to an embodiment of the present invention; FIG.

6 is another schematic diagram of a method for adjusting a contention window in an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a network device according to an embodiment of the present invention;

FIG. 8 is another schematic structural diagram of a network device according to an embodiment of the present invention;

FIG. 9 is another schematic structural diagram of a network device according to an embodiment of the present invention.

detailed description

The present application provides a method of adjusting a contention window that is applicable to a wireless communication system. Referring to FIG. 2, the wireless communication system includes a network device and a terminal. The network device refers to the base station 201 or the micro base station 203, and may also be an access point or other access network device. The base station 201 corresponds to the macro cell 202, and the micro base station 203 corresponds to the small cell 204. The terminal 205 can be a personal computer, a mobile phone, a tablet computer, a car computer, a kiosk or a personal digital assistant.

Referring to FIG. 3, the present application provides a network device 300. The network device 300 includes one or more transceivers 301, one or more processors 302, one or more memories 303, one or more network interfaces 304. The transceiver 301, the processor 302, the memory 303, and the network interface 304 are connected by a bus.

The transceiver 301 includes a receiver Rx and a transmitter Tx, and the transceiver 301 is coupled to an antenna or an antenna array. The network interface 304 is connected to the core network via a link (e.g., a link to the core network) or to other base stations via a wired or wireless link. The memory 303 includes a random access memory (RAM), and may further include at least one non-volatile memory (NVM) such as a magnetic disk. Memory 303 is used to store computer program code. The processor 302 can perform the method of adjusting the contention window in the present application by calling the program code stored in the memory 303.

Based on the network device described above, the present application provides a method for adjusting a contention window to solve the problem of low channel utilization in the prior art. Referring to FIG. 4, an embodiment of a method for adjusting a contention window provided by the present application includes:

Step 401: The network device receives feedback information of the downlink data sent by the terminal of the first cell to the first time period.

In this embodiment, after the network device sends the downlink data to the terminal of the first cell, the network device may receive the feedback information of the downlink data of the terminal of the first cell. When the terminal correctly receives data, it sends an acknowledgement message, such as ACK, to the network device. When the terminal does not correctly receive data, it sends a negative message, such as NACK or "any", to the network device.

Step 402: The network device collects, in the first time period, the acknowledgement message fed back by each terminal accounts for the proportion of all feedback information.

Specifically, the network device can calculate, according to the number of feedback acknowledgement messages and the number of denied acknowledgement messages sent by each terminal in the first time period, the ratio of the acknowledgement messages fed back by each terminal to the total feedback information of each terminal. For example, the terminal 1 feeds back 100 ACKs to the network device in the first time period, and feeds back 200 NACKs, and the ACK ratio is 100/(100+200)=1/3.

Step 403: The network device determines that the terminal that is to send the downlink data in the first target subframe is the to-be-scheduled terminal, and selects, according to the statistical result, the terminal that meets the communication quality requirement from the to-be-scheduled terminal as the first target terminal.

The first target subframe is a subframe for setting a contention window of the next transmission data after the first time period, for example, a first downlink subframe with valid HARQ feedback after the first time period.

When the network device has downlink data to be sent, there are N terminals to be scheduled in the first target subframe. In fact, network resources (such as time-frequency resources) of the network device are limited, and only downlink data is sent to n terminals. n ≤ N. Therefore, the network device selects n terminals from the N terminals as scheduling terminals. If the acknowledgement message of the terminal is high, it means that the communication quality of the terminal is reliable, otherwise the communication quality of the terminal is not reliable. The network device may select the first target terminal from the to-be-scheduled terminal according to the proportion of the acknowledgement message fed back by the terminal.

It should be noted that, in addition to selecting a terminal that meets the communication quality requirement according to the ratio of the confirmation message to the total feedback information, the present application may also select a terminal that meets the communication quality requirement according to the ratio of the confirmation message to the denied message.

Step 404: The network device sends the first downlink data to the first scheduling terminal that includes the first target terminal in the first target subframe. The first downlink data corresponds to the first target subframe, which is downlink data sent in the first target subframe.

Step 405: The network device sets a contention window for sending data next time according to the feedback information of the first scheduling terminal to the first downlink data.

Specifically, after the first downlink data is sent to the first scheduling terminal, the network device receives the feedback information of the first downlink data by the first scheduling terminal, and sets the feedback information of the first downlink data to the first scheduling terminal. The contention window for sending data. Since the first target terminal is a terminal that meets the communication quality requirement, when the number of the first target terminals is equal to or exceeds 20% of the number of the first scheduling terminals, the feedback result of the first downlink data is generally a confirmation message, according to the current There is a agreement that the next time the contention window for sending data will be set to the minimum contention window.

It should be noted that, in other downlink subframes after the first target subframe, the network device may still send downlink data to the terminal according to a scheduling policy specified by the existing protocol.

The contention window for sending data this time is CW1, and the contention window for the next data transmission is CW2. In the prior art, if the feedback information of the first downlink data is a negative message, according to the 3GPP protocol, CW2=2×CW1. The network device continues to send downlink data to the terminal because the priority of the terminal that receives the first downlink data is high. In the case where the communication connection is not good, in order to correctly transmit data to the above terminal, the network device will continuously expand the contention window for the next data transmission. At this point, the competition window continues to expand, and the backoff time increases, resulting in low channel utilization.

In this embodiment, by scheduling a terminal that satisfies the communication quality requirement in the first target subframe, it is possible to effectively limit the continuous expansion of the contention window, thereby shortening the backoff time before the next data transmission, thereby improving channel utilization.

In an optional embodiment, before the step 402, the method further includes: setting, by the network device, a lower limit of a desired scheduling duration of the first cell;

Step 402 may be specifically: if it is detected that the duration of the first cell occupied carrier is less than the expected scheduling duration lower limit in the first time period, the network device collects feedback information of the downlink data sent by the terminal of the first cell to the first time period.

In this embodiment, the carrier used by the network device to send data to the terminal of the first cell may be any carrier configured by the network device, and the carrier may be composed of several subcarriers. The network device determines whether the duration of the carrier occupied by the first cell in the first time period is less than the lower limit of the expected scheduling duration. If the time is less, indicating that the duration of the carrier occupied by the first cell is small, step 402 is performed. The method for adjusting the contention window in the embodiment shown in FIG. 4 can improve the utilization of the carrier by the first cell, and send more data to the terminal of the first cell through the carrier. If it is not smaller, it indicates that the duration of the carrier occupied by the first cell is reasonable, and step 402 may not be performed.

It should be noted that the lower limit of the expected scheduling duration of each cell may be allocated by the core network device, or may be set by the network device according to the time of the carrier occupied by the cell.

Further, the network device determines that the lower limit of the expected scheduling duration of the first cell may be:

The network device determines, according to a data rate average value of the first cell in the second time period and a data transmission rate of a Radio Link Control (RLC) layer entry of the first cell in the second time period, determining the expected occupation of the first cell. The time ratio of the carrier is determined according to the idle channel estimation result of the carrier in the second period, and the duration of the occupied carriers of the other cells in the second period is determined according to the duration of the occupied carriers of the other cells in the second period and the duration of the second period. The proportion of the time that the other cell is expected to occupy the carrier; the lower limit of the expected scheduling duration of the first cell is determined according to the proportion of time that the first cell expects to occupy the carrier, the proportion of time that the other cell expects to occupy the carrier, and the duration of the first time period.

In this embodiment, the network device selects one time period before the first time period as the second time period, and the duration of the second time period is recorded as T2. During the second time period, the network device measures the data transmission rate average r1 of the first cell and the data transmission rate r2 of the RLC layer entry, and calculates a time ratio Ls=q1×r1/r2 of the first cell expected to occupy the carrier. Q1 is a weighting coefficient and takes a value of 1 or other value close to 1. In addition, the network device performs the idle channel estimation on the carrier in the second period, determines the duration t1 of the occupied carrier of the other cell, calculates the ratio of the expected occupied carrier time of other cells according to t1 and T2, Lo=q2×t1/T2, and the other cells are in addition to the first A cell that occupies a carrier in a second period outside the cell. Q2 is a weighting coefficient and takes a value of 1 or other values close to 1. The time is then Ls, Lo T2, and calculating an expected schedule length limit S _min.

For example, the correspondence between the scheduling durations S, Ls, Lo, and T1 may be as follows: When Ls+Lo≤100%, then S=1000×T1×Ls/(Ls+Lo). When Ls+Lo>100%, Ls>50%, Lo>50%, then S=1000×T1×50%. When Ls+Lo>100%, Ls>50%, Lo<50%, then S=1000×T1×(1-Lo). When Ls+Lo>100%, Ls<50%, Lo>50%, then S=1000×T1×Ls. T1 is the duration of the first time period, and the unit may be milliseconds (ms). The calculation formula of the desired scheduling time limit S _min can be as follows: S _min =q3×S. Q3 is any value in (0, 1).

In another optional embodiment, the step 403 may be: the network device sorts the ratio of the acknowledgement message fed back by the terminal to be scheduled to the total feedback information from large to small, and determines that the first n terminals are terminals that meet the communication quality requirement. The first n terminals are used as the first target terminal.

In this embodiment, the greater the ratio of the acknowledgement message to the total feedback information, the more reliable the communication quality is, and the smaller the ratio of the acknowledgement message to the total feedback information is, indicating that the communication quality is less reliable. The network device selects the first n terminals as the first target terminal, and n is not greater than the number of network resources of the network device, that is, the first target terminal is a part of the terminal with the best communication quality among the to-be-scheduled terminals, and the network device can determine that it meets the communication quality requirement. . Compared with sending the downlink data to the other terminals in the to-be-scheduled terminal, when the network device sends the first downlink data to the first scheduling terminal, the first target subframe corresponds to The feedback information has a higher probability of confirming the message, and the probability of adjusting the next contention window to the minimum contention window is also the largest, so that the backoff time can be effectively shortened and the channel utilization rate can be improved. It can be understood that the network device can also select n other terminals as the first target terminal, for example, according to the above ranking, select the terminal from sequence number 2 to serial number (n+1) as the first target terminal, or The terminal from the sequence number 3 to the sequence number (n+2) is selected as the first target terminal, and the other methods for selecting the terminal as the first target terminal can be deduced by analogy, and details are not described herein again.

In another optional embodiment, the step 403 may be specifically: the network device determines, from the to-be-scheduled terminal, that the terminal whose acknowledgment message occupies the total of the feedback information exceeds the first preset threshold is a terminal that meets the communication quality requirement, and is satisfied. All or part of the terminal required for communication quality serves as the first target terminal.

In this embodiment, the first preset threshold is used to determine whether the communication connection between the terminal and the network device meets the communication quality requirement, and the value may be set according to actual conditions. If the number of the feedback acknowledgement messages in the first time period exceeds the first preset threshold, determining that the communication connection between the terminal and the network device meets the communication quality requirement. Otherwise, the above communication connection does not meet the communication quality requirements. Compared with the prior art, after the first target subframe transmits the first downlink data to the terminal with reliable communication quality, the probability that the feedback information corresponding to the first downlink data is a confirmation message is greater, and the next The probability that the competition window is adjusted to the minimum contention window is also larger, so that the backoff time can be effectively shortened and the channel utilization rate can be improved.

In the case that each cell has data to transmit, if one cell occupies a long carrier time and other cells occupy a carrier for a short time, the channel allocation may be uneven. The application can increase the backoff duration of the current cell when the current cell occupies a carrier for a long time, thereby increasing the opportunity for other cells to occupy the carrier and achieving the effect of a fair competition channel. Based on the embodiment shown in FIG. 4, another embodiment of the method for adjusting contention window provided by the present application includes:

Step 501: The network device determines an upper limit of a desired scheduling duration of the first cell.

In this embodiment, the upper limit of the expected scheduling duration of each cell may be allocated by the core network device, or may be set by the network device according to the time of the carrier occupied by the cell.

Step 502: When it is detected that the duration of the first cell occupied carrier is greater than the expected scheduling duration upper limit in the first time period, the network device selects the unsatisfied terminal from the to-be-scheduled terminal according to the ratio of the acknowledgment message occupies all the feedback information in the first time period. The terminal of communication quality requirement is used as the second target terminal.

When it is detected that the duration of the first cell occupying the carrier in the first time period is greater than the upper limit of the expected scheduling time of the first cell, it indicates that the duration of the occupied cells of other cells is too short, and the channel allocation is uneven. At this time, it is necessary to re-allocate the channel occupancy ratio so that each cell can compete for the channel fairly.

After obtaining the foregoing detection result, the network device collects the ratio of the negative feedback message fed back by each terminal in the first time period to the total feedback information, and determines that the terminal that needs to send the downlink data in the first target subframe is the to-be-scheduled terminal, according to the statistical result. And selecting, from the terminal to be scheduled, a terminal that does not meet the communication quality requirement as the second target terminal.

Step 503: The network device sends the second downlink data to the second scheduling terminal that includes the second target terminal in the first target subframe.

Step 504: The network device sets, according to the feedback information of the second downlink data by the second scheduling terminal, a contention window for sending data next time.

Specifically, after the first target subframe sends the second downlink data to the second scheduling terminal that includes the second target terminal, the network device receives the feedback information of the second downlink data by the second scheduling terminal, according to the second scheduling terminal. The feedback information of the two downlink data sets the contention window for the next data transmission.

The contention window for sending data this time is CW1, and the contention window for the next data transmission is CW2. If the second target terminal is a terminal that does not meet the communication quality requirement, when the number of the second target terminal exceeds 80% of the number of the second scheduling terminal, the feedback result of the first downlink data is generally a negative message, and CW2=2 ×CW1. In accordance with this implementation, the competition window will continue to expand, and the back-off time will increase. In the application, when the channel allocation is uneven, the contention window is expanded, and the backoff time of the data transmitted by the network device of the cell is increased, and other cells can occupy the carrier in the backoff time. It can be seen that the embodiment of the present invention can improve the opportunity for other cells to occupy a carrier and achieve the purpose of fair competition channel.

In an optional embodiment, step 501 may be specifically: the network device determines, according to a data rate average of the first cell in the second time period and a data transmission rate of the RLC layer entry of the first cell in the second time period, the first cell. Determining the time ratio of the occupied carrier; determining the duration of the occupied carriers of the other cells in the second period according to the idle channel estimation result of the carrier in the second period, according to the duration of the occupied carriers of the other cells in the second period and the duration of the second period The ratio of the time that the other cell is expected to occupy the carrier is determined; the upper limit of the expected scheduling duration of the first cell is determined according to the proportion of time that the first cell expects to occupy the carrier, the proportion of time that the other cell expects to occupy the carrier, and the duration of the first time period.

Specifically, the network device selects one time period before the first time period as the second time period, and the duration of the second time period is recorded as T2. During the second time period, the network device measures the data transmission rate average r1 of the first cell and the data transmission rate r2 of the RLC layer entry, and calculates a time ratio Ls=q1×r1/r2 of the first cell expected to occupy the carrier. Q1 is a weighting coefficient and takes a value of 1 or other value close to 1. In addition, the network device performs the idle channel estimation on the carrier in the second period, determines the duration t1 of the occupied carriers of other cells, and calculates the ratio of the expected occupied carrier time of other cells according to t1 and T2, Lo=q2×t1/T2. The other cell is a cell that occupies a carrier in the second period except the first cell. Q2 is a weighting coefficient and takes a value of 1 or other values close to 1. The desired scheduling duration upper limit S _{max is} then calculated from Ls, Lo, and T2.

For example, the correspondence between the scheduling durations S, Ls, Lo, and T1 may be as follows: When Ls+Lo≤100%, then S=1000×T1×Ls/(Ls+Lo). When Ls+Lo>100%, Ls>50%, Lo>50%, then S=1000×T1×50%. When Ls+Lo>100%, Ls>50%, Lo<50%, then S=1000×T1×(1-Lo). When Ls+Lo>100%, Ls<50%, Lo>50%, then S=1000×T1×Ls. T1 is the duration of the first period, and the unit can be ms. The calculation formula of the expected scheduling time upper limit S _max may be as follows: S _max =q4×S. Q4 is greater than 1.

The network device can select a terminal that does not meet the communication quality requirement by using various methods. For details, refer to the following embodiments.

Based on the embodiment shown in FIG. 5, in an optional embodiment, step 502 may be specifically: the network device sorts the ratio of the denial message fed back by the terminal to be scheduled to the total feedback information from large to small, and selects the first n terminals as the The second target terminal.

In this embodiment, n is not greater than the number of network resources of the network device. The greater the proportion of denial messages in all feedback information, the less reliable the communication quality, and the smaller the proportion of denial messages in the total feedback information, indicating that the communication quality is more reliable. The network device selects the first n terminals as the second target terminal, that is, the second target terminal is the part of the terminal to be scheduled that has the worst communication quality. When the network device sends the second downlink data to the second scheduling terminal, the probability that the feedback information corresponding to the second target subframe is a negative message is greater, and the next competition is to be compared with that of the other terminals in the terminal to be scheduled. The probability of window expansion is also the largest, so it can effectively increase the backoff time and increase the chance of other network devices occupying the carrier.

Based on the embodiment of FIG. 5, in another optional embodiment, the step 502 may be specifically: determining that the terminal whose denial message accounts for all the feedback information exceeds the second preset threshold is a terminal that does not meet the communication quality requirement, and will not Satisfaction All or part of the terminal of the quality requirement is used as the second target terminal.

In this embodiment, the second preset threshold is used to determine whether the communication connection between the terminal and the network device meets the communication quality requirement, and the value may be set according to actual conditions. If the number of the feedback acknowledgement messages exceeds the second preset threshold in the first time period, it is determined that the communication connection between the terminal and the network device does not meet the communication quality requirement. Otherwise, it cannot be determined that the above communication connection does not satisfy the communication quality requirement. Compared with the prior art, after the network device sends the second downlink data to the terminal with unreliable communication quality, the probability that the feedback information corresponding to the second downlink data is a negative message is greater, thereby increasing the probability of expanding the contention window. Increase the backoff time and increase the chance of other cells occupying the carrier.

For ease of understanding, the method for adjusting the contention window provided by the present application is described in detail in a specific application scenario:

In this specific application scenario, the network device takes a base station as an example, and the terminal of the cell 1 takes 50 terminals as an example. Referring to FIG. 6, the network device sends downlink data to the terminal of the cell 1 through the carrier in the first period, the first target. A subframe (ie, subframe k) refers to a first downlink subframe in which there is valid HARQ feedback after the first time period. In the first time period, the number of downlink subframes is 200. The feedback information of the terminal of the cell 1 for transmitting downlink data in the first time period is as follows:

	子帧1Subframe 1	子帧2Subframe 2	子帧3Subframe 3	…...	子帧200Subframe 200
终端1Terminal 1	ACKACK	NACKNACK	NACKNACK	…...	NULLNULL
终端2Terminal 2	NACKNACK	ACKACK	ACKACK	…...	NACKNACK
终端3Terminal 3	NULLNULL	ACKACK	ACKACK	…...	ACKACK
终端4Terminal 4	NACKNACK	NULLNULL	NACKNACK	…...	NULLNULL
终端5Terminal 5	NACKNACK	NULLNULL	NULLNULL	…...	NULLNULL
…...	…...	…...	…...	…...	…...
终端50Terminal 50	NULLNULL	NACKNACK	NACKNACK	…...	NULLNULL

Where NULL indicates that the base station does not schedule the terminal in the subframe.

It is assumed that the terminal to be scheduled includes the terminal 1 to the terminal 10. The network resources of the base station can only support sending downlink data to the four terminals.

The base station counts the ratio of ACK/NACK feedback from each terminal to all feedback information, and sorts the ACK ratio from large to small, and assumes that terminal 3, terminal 4, terminal 5, and terminal 6 are the first four terminals, and the first backoff time. After that, the subframe k in the first scheduling process transmits downlink data to the terminal 3, the terminal 4, the terminal 5, and the terminal 6. When any of the terminals feeds back an ACK, such as the ACK fed back by the terminal 3, the ACK accounts for 25% of the total feedback result, and the ratio of the feedback information of the subframe k to the NACK is necessarily lower than 80%, and the feedback information of the subframe k can be seen. For ACK. Under the agreement, the CW2 set CW _min, and then select a second backoff time from CW _min.

The first scheduling terminal selected according to the existing scheduling policy, the terminal 1, the terminal 2, the terminal 4, and the terminal 5 in the above table are taken as an example, and the subframe k in the first scheduling process is directed to the terminal 1, the terminal 2, the terminal 4, and the terminal 5. Send downlink data. It is assumed that the proportion of the ACKs received by the terminal 1, the terminal 2, the terminal 4, and the terminal 5 is less than 20%. According to the statistical result of the feedback ACK/NACK, the feedback result corresponding to the subframe k is likely to be a NACK, and then in the second scheduling process. The competition window CW2 will become twice the CW1, and then the second backoff time is selected from CW2. In the case of continuous data transmission failure, the contention window will gradually increase until the maximum contention window. The backoff time selected from the maximum contention window will be large, and since the backoff time does not send downlink data, the channel utilization is very low.

In an alternative embodiment, the duration of the second time period is 1 s. The average data transmission rate of the cell 1 in the second period is 50 Mbps, and the data transmission rate of the RLC layer entrance is 100 Mbps, and q1 is 1. The base station determines that the Ls of the cell 1 is 50%. The base station performs an idle channel estimation on the current carrier, and assumes that the duration of the occupied carrier of the other cell is 250 ms, and Lo is determined to be 25%. Q3 takes 0.8 as an example, and determines the lower limit of the desired scheduling time S _min = 0.8 × (1 - 0.25) × 1000 = 600 ms according to Ls, Lo, and T1. If it is detected that the duration of the occupied carrier of the cell 1 is 400 ms, the base station may determine that the duration of the occupied carrier of the cell 1 is less than the lower limit of the expected scheduling time according to 400 ms < 600 ms, and triggers the base station to count the acknowledgement message of the terminal feedback of the cell 1 in the first time period. The step of the proportion of feedback information.

Q4 takes 1.2 as an example, and the base station sets the upper limit of the desired scheduling time S _max = 0.8 × (1 - 0.25) × 1000 = 900 ms. If the duration of the occupied carrier of the cell 1 is 950 ms, the base station may determine that the duration of the occupied carrier of the cell 1 is greater than the upper limit of the expected scheduling time according to 900 ms < 950 ms. The base station selects, from the terminal 1 to the terminal 10, a part of the terminals that have the most NACK feedback in the first time period, and takes the terminal 7, the terminal 8, the terminal 9, and the terminal 10 as an example.

The base station transmits downlink data to the terminal 7, the terminal 8, the terminal 9, and the terminal 10 in the subframe k. If the feedback information of the terminal is NACK, the feedback information corresponding to the subframe k is NACK, and the contention window CW2 of the second scheduling process is adjusted to be twice the competition window CW1 of the first scheduling process, so that the backoff time of the cell 1 is As the number of other cells occupying a carrier increases, the goal of a fair competition channel can be achieved.

Referring to FIG. 7, the present application provides a network device 700, which can implement the functions of the network device in the embodiment shown in FIG. 4 to FIG. Network device 700 includes:

The receiving module 701 is configured to receive feedback information of the downlink data sent by the terminal of the first cell to the first time period;

The statistics module 702 is configured to calculate a ratio of the acknowledgement message fed back by each terminal in the first time period to the total feedback information;

The selecting module 703 is configured to determine that the terminal that is to send the downlink data in the first target subframe is the to-be-scheduled terminal, and select, according to the statistical result, the terminal that meets the communication quality requirement from the to-be-scheduled terminal as the first target terminal, and the first target subframe. a subframe for setting a contention window for the next transmission of data after the first time period;

The sending module 704 is configured to send the first downlink data to the first scheduling terminal that includes the first target terminal in the first target subframe.

The setting module 705 is configured to set a contention window for sending data next time according to the feedback information of the first scheduling terminal to the first downlink data.

Based on the embodiment shown in FIG. 7 , in another optional embodiment, the selecting module 703 is specifically configured to sort the proportion of the acknowledgement message fed back by the terminal to be scheduled to the total feedback information from large to small; determining that the first n terminals are satisfied A terminal that requires communication quality, the first n terminals are used as the first target terminal, and n is not greater than the number of network resources of the network device.

Based on the embodiment shown in FIG. 7 , in another optional embodiment, the selecting module 703 is specifically configured to determine, from the to-be-scheduled terminal, that the terminal that the acknowledgement message occupies the total feedback information exceeds the first preset threshold to satisfy the communication quality. The required terminal uses all or part of the terminal satisfying the communication quality requirement as the first target terminal.

Referring to FIG. 8 , based on the embodiment shown in FIG. 7 or the optional embodiment, in another optional embodiment, the network device 700 further includes:

The first determining module 801 is configured to determine, before the terminal of the first cell, the feedback information of the downlink data sent by the first time period, the lower limit of the expected scheduling duration of the first cell;

The statistic module 702 is specifically configured to: if it is detected that the duration of the first cell occupied carrier is smaller than the expected scheduling duration lower limit in the first time period, the feedback information of the downlink data sent by the terminal of the first cell to the first time period is calculated.

Further, in another optional embodiment, the first determining module 801 is specifically configured to: according to a data rate average of the first cell in the second time period and a radio link layer control protocol RLC of the first cell in the second time period. The data transmission rate of the layer entry determines the proportion of time that the first cell expects to occupy the carrier, and the second time period is before the first time period; and determines the duration of the other cells occupying the carrier in the second time period according to the idle channel estimation result of the carrier in the second time period. Determining, according to the duration of the other cells occupying the carrier and the duration of the second period in the second period, determining the proportion of time that the other cells are expected to occupy the carrier, and the other cells are the cells occupying the carrier in the second period except the first cell; The ratio of the time that a cell is expected to occupy the carrier, the proportion of time that the other cell expects to occupy the carrier, and the duration of the first time period determine the lower limit of the desired scheduling duration of the first cell.

Referring to FIG. 9, based on the embodiment shown in FIG. 7 or the optional embodiment, in another optional embodiment, the network device 700 further includes:

a second determining module 901, configured to determine an upper limit of a desired scheduling duration of the first cell;

The selecting module 703 is further configured to: when detecting that the duration of the first cell occupied carrier is greater than the expected scheduling duration upper limit in the first time period, select, according to the ratio of the acknowledgment message to the total feedback information in the first time period, select from the to-be-scheduled terminal A terminal that does not meet the communication quality requirement is used as the second target terminal;

The sending module 704 is further configured to send the second downlink data to the second scheduling terminal that includes the second target terminal in the first target subframe.

The setting module 705 is further configured to set, according to the feedback information of the second downlink data by the second scheduling terminal, a contention window for sending data next time.

Further, in another alternative embodiment,

The second determining module 901 is specifically configured to determine, according to a data rate average value of the first cell in the second time period and a data transmission rate of the RLC layer entry of the first cell in the second time period, a time ratio of the first cell expected to occupy the carrier, The second time period is before the first time period; determining the duration of the other cells occupying the carrier in the second time period according to the idle channel estimation result of the carrier in the second time period, according to the duration and the second time period of the other cells occupying the carrier in the second time period The duration of time, determining the proportion of time that other cells are expected to occupy the carrier, and the other cells are cells occupying the carrier in the second period except the first cell; the proportion of time that the first cell expects to occupy the carrier, and the proportion of time that other cells expect to occupy the carrier And a duration of the first time period, determining an upper limit of a desired scheduling time of the first cell.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, it may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present invention are generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center Transfer to another website site, computer, server, or data center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.). The computer readable storage medium can be Any available media that can be stored by a computer or a data storage device such as a server, data center, or the like that includes one or more available media integrations. The usable medium may be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a Solid State Disk (SSD)) or the like.

The above embodiments are only used to explain the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still The technical solutions described in the embodiments are modified, or the equivalents of the technical features are replaced by the equivalents. The modifications and substitutions of the embodiments do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

A method for adjusting a contention window, comprising:

Receiving, by the network device, the feedback information of the downlink data sent by the terminal of the first cell to the first time period, and counting the proportion of the acknowledgement message fed back by each terminal in the first time period to the total feedback information;

Determining, by the network device, that the terminal that is to send the downlink data in the first target subframe is the to-be-scheduled terminal, and selecting, according to the statistical result, the terminal that meets the communication quality requirement from the to-be-scheduled terminal as the first target terminal, where the first The target subframe is a subframe for setting a contention window for transmitting data next time after the first time period;

Transmitting, by the network device, the first downlink data to the first scheduling terminal that includes the first target terminal in the first target subframe;

The network device sets a contention window for the next data transmission according to the feedback information of the first scheduling terminal to the first downlink data.
The method according to claim 1, wherein the network device selects, as the first target terminal, the terminal that meets the communication quality requirement from the to-be-scheduled terminal according to the statistical result, the method includes:

The network device sorts the proportion of the acknowledgement message fed back by the to-be-scheduled terminal to all the feedback information from large to small;

The network device determines that the first n terminals are terminals that meet the communication quality requirement, and the first n terminals are used as the first target terminal, and the n is not greater than the network resource quantity of the network device.
The method according to claim 1, wherein the network device selects, as the first target terminal, the terminal that meets the communication quality requirement from the to-be-scheduled terminal according to the statistical result, the method includes:

The network device determines, from the to-be-scheduled terminal, that the terminal whose acknowledgment message occupies the total of the feedback information exceeds the first preset threshold is a terminal that meets the communication quality requirement, and all or part of the terminal that satisfies the communication quality requirement As the first target terminal.
The method according to any one of claims 1 to 3, wherein before the network device counts feedback information of the downlink data sent by the terminal of the first cell to the first time period, the method further includes: Determining, by the network device, a lower limit of a desired scheduling duration of the first cell;

The network device collects, by the network device, the feedback information of the downlink data that is sent by the terminal of the first cell to the first time period, if the duration of the occupied carrier of the first cell in the first time period is less than the lower limit of the expected scheduling time, the network device The feedback information of the downlink data sent by the terminal of the first cell to the first time period is counted.
The method according to claim 4, wherein the determining, by the network device, the lower limit of the expected scheduling duration of the first cell comprises:

Determining, by the network device, that the first cell is expected to occupy a carrier according to a data rate average value of the first cell in the second time period and a data transmission rate of the radio link layer control protocol RLC layer entry of the first cell in the second time period a time ratio, the second time period being before the first time period;

Determining, by the network device, a duration of the occupied carriers of the other cells in the second period according to the idle channel estimation result of the carrier in the second period, according to the duration of the occupied carriers of the other cells in the second period, and the second period of time Determining a time ratio of the other cells that are expected to occupy a carrier, the other cells being cells occupying a carrier in a second time period except the first cell;

Determining, by the network device, a lower limit of a desired scheduling duration of the first cell according to a ratio of a time period in which the first cell is expected to occupy a carrier, a time ratio in which the other cell is expected to occupy a carrier, and a duration of the first time period.
The method according to any one of claims 1 to 3, wherein the method further comprises: the network device determining an upper limit of a desired scheduling duration of the first cell;

When it is detected that the duration of the first cell occupied carrier is greater than the expected scheduling duration upper limit in the first time period, the network device is configured to be scheduled according to a ratio of denying the message to all feedback information in the first time period. Selecting, by the terminal, a terminal that does not meet the communication quality requirement as the second target terminal;

Transmitting, by the network device, the second downlink data to the second scheduling terminal that includes the second target terminal in the first target subframe;

And the network device sets a contention window for sending data next time according to the feedback information of the second scheduling terminal to the second downlink data.
The method according to claim 6, wherein the determining, by the network device, an upper limit of a desired scheduling duration of the first cell comprises:

Determining, by the network device, a time ratio of a first cell to occupy a carrier according to a data rate average of the first cell in a second time period and a data transmission rate of an RLC layer entry of the first cell in a second time period, where The second time period is before the first time period;

Determining, by the network device, the duration of the occupied carriers of the other cells in the second period according to the idle channel estimation result of the carrier in the second period, according to the duration of the occupied carriers of the other cells in the second period, and the second Determining, by the duration of the time period, a proportion of time that the other cell expects to occupy a carrier, where the other cell is a cell occupying a carrier in a second time period except the first cell;

And determining, by the network device, an upper limit of a desired scheduling duration of the first cell according to a ratio of a time period in which the first cell is expected to occupy a carrier, a time ratio in which the other cell is expected to occupy a carrier, and a duration of the first time period.
A network device, comprising:

a receiving module, configured to receive feedback information of the downlink data sent by the terminal of the first cell to the first time period;

a statistics module, configured to count the proportion of the acknowledgement message fed back by each terminal in the first time period to the total feedback information;

a selection module, configured to determine that the terminal that is to send the downlink data in the first target subframe is the to-be-scheduled terminal, and select, according to the statistical result, the terminal that meets the communication quality requirement from the to-be-scheduled terminal as the first target terminal, where the first The target subframe is a subframe for setting a contention window for transmitting data next time after the first time period;

a sending module, configured to send, in the first target subframe, first downlink data to a first scheduling terminal that includes the first target terminal;

And a setting module, configured to set a contention window for sending data next time according to the feedback information of the first scheduling terminal to the first downlink data.
A network device according to claim 8, wherein

The selecting module is specifically configured to sort the proportion of the acknowledgement message fed back by the to-be-scheduled terminal to all the feedback information from large to small; determining that the first n terminals are terminals satisfying the communication quality requirement, and using the first n terminals as The first target terminal, where n is not greater than the number of network resources of the network device.
The network device according to claim 8, wherein the selection module is specifically configured to receive from the In the scheduling terminal, the terminal that determines that the ratio of the acknowledgment message to the total of the feedback information exceeds the first preset threshold is a terminal that satisfies the communication quality requirement, and all or part of the terminal that satisfies the communication quality requirement is used as the first target terminal.
The network device according to any one of claims 8 to 10, wherein the network device further comprises:

a first determining module, configured to determine, after the terminal of the first cell, the feedback information of the downlink data sent by the first time period, the lower limit of the expected scheduling duration of the first cell;

The statistic module is configured to: if it is detected that the duration of the first cell occupied carrier is less than the expected scheduling duration lower limit in the first time period, the feedback information of the downlink data sent by the terminal of the first cell to the first time period is collected. .
The network device according to claim 11, wherein

a first determining module, configured to determine, according to a data rate average value of the first cell in the second time period and a data transmission rate of the radio link layer control co-RLC layer entry of the first cell in the second time period, the first cell Determining a time ratio of the occupied carrier, the second time period being before the first time period; determining, according to the idle channel estimation result of the carrier in the second time period, a duration of occupying a carrier by another cell in the second time period; Determining a time ratio of the other cells occupying the carrier in the second time period, and determining a time ratio of the other cells occupying the carrier, wherein the other cells occupy the carrier in the second time period except the first cell a cell; determining, according to a time ratio of the first cell to occupy the carrier, a time ratio of the other cell to occupy the carrier, and a duration of the first time period, determining a lower limit of the expected scheduling duration of the first cell.
The network device according to any one of claims 8 to 10, wherein the network device further comprises:

a second determining module, configured to determine an upper limit of a desired scheduling duration of the first cell;

The selecting module is further configured to: when detecting that the duration of the first cell occupying the carrier is greater than the expected scheduling duration upper limit in the first time period, according to the proportion of the negative feedback information in the first time period, Selecting, by the terminal to be scheduled, a terminal that does not meet the communication quality requirement as the second target terminal;

The sending module is further configured to send, in the first target subframe, second downlink data to a second scheduling terminal that includes the second target terminal;

The setting module is further configured to set a contention window for sending data next time according to the feedback information of the second scheduling terminal to the second downlink data.
A network device according to claim 13, wherein

The second determining module is configured to determine, according to an average value of the data rate of the first cell in the second time period and a data transmission rate of the RLC layer in the second time period of the first cell, a time ratio of the carrier, the second time period is before the first time period; determining, according to a result of the idle channel estimation of the second time period of the carrier, a duration of occupying a carrier by another cell in the second time period, according to Determining a time ratio of the other cells occupying the carrier in the second time period, and determining a time ratio of the other cells occupying the carrier, wherein the other cells occupy the carrier in the second time period except the first cell a cell; determining, according to a time ratio of the first cell to occupy the carrier, a time ratio of the other cell to occupy the carrier, and a duration of the first time period, determining an upper limit of the expected scheduling duration of the first cell.
A computer readable storage medium comprising instructions that, when executed on a computer, cause the computer to execute A method as claimed in any one of claims 1 to 7.
A computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of claims 1-7.