Method and station for dynamic adaptation of backoff time

Abstract

The application discloses a dynamic self-adaptive adjustment method and station of backoff time, and the method comprises the following steps: identifying the STA density of the WIFI network to which the station STA belongs; calculating the collision cost time according to the STA density; calculating the idle waiting time according to the STA density; obtaining the random number value range when the packet sending expected time is the minimum value, wherein the packet sending expected time is the sum of the collision cost time and the idle waiting time; and calculating the backoff time according to the random number value range. By using the application, the backoff time can be dynamically and self-adaptively adjusted.

Description

Technical Field

[0001] This invention relates to the field of wireless access technology, specifically to a dynamic adaptive adjustment method and site for backoff time. Background Technology

[0002] Wi-Fi is a common wireless access method. Since multiple STAs (Stations) can connect to the same access point (AP) via Wi-Fi, a contention-based access mode, or DCF (Directed Coordination Function), was designed to address the issue of data collisions when STAs simultaneously transmit data on the same Wi-Fi network. In this mode, when any STA needs to transmit data to the AP via Wi-Fi, it must first detect the ambient electromagnetic field. If the ambient electromagnetic field is detected as idle, data is transmitted directly. If the ambient electromagnetic field is detected as busy, the STA must wait for a period of time.

[0003] In existing solutions, the waiting strategy employed by the STA is to wait for a distributed coordination frame interval (Difs) plus a backoff time (time). Difs is a fixed value defined by the standard protocol, while the backoff time (time) is calculated by each STA using the formula: time = Cw * random number, where RND = uniform(0, num), a random number generation function that generates a uniformly distributed random number (0, num). In existing technologies, STAs generate their own random numbers to avoid collisions caused by multiple STAs sending data simultaneously at the same time. By using random numbers, multiple STAs can queue without knowing each other's data. However, in existing technologies, the range of this random number, i.e., the value of num, is defined by the STA and is a static, fixed value. Therefore, if the range of the random number is too small, the probability of collisions increases. A larger range is reasonable for scenarios with multiple STAs and a single AP, but for scenarios with a limited number of STAs, setting the random number too large is a waste of resources and results in longer waiting times. Summary of the Invention

[0004] This invention provides a method and site for dynamically adaptively adjusting the rollback time, for dynamically adaptively adjusting the rollback time. The technical solution is as follows:

[0005] On the one hand, a dynamic adaptive adjustment method for backoff time is provided, the method comprising:

[0006] Identify the STA density of the Wi-Fi network to which the STA belongs;

[0007] Calculate the conflict cost time based on the STA density;

[0008] Calculate the idle waiting time based on the STA density;

[0009] Obtain the range of random numbers that take the minimum packet sending time, where the estimated packet sending time is the sum of the conflict cost time and the idle waiting time;

[0010] The rollback time is calculated based on the range of random number values.

[0011] Optionally, when the STA first accesses the wireless access point AP, the STA identifies the STA density of the WIFI network to which the STA belongs;

[0012] Or the STA density of the WIFI network to which the STA periodically identifies the site;

[0013] Alternatively, if the number of collisions encountered by the STA exceeds a preset value, the STA identifies the STA density of the WIFI network to which the STA belongs.

[0014] Optionally, identifying the density of STAs belonging to the WIFI network specifically includes:

[0015] The STA requests the AP to obtain the density of STAs belonging to the same WIFI network as the STA;

[0016] Alternatively, the STA may probe to obtain the density of STAs belonging to the same Wi-Fi network.

[0017] Optionally, the STA requests the AP to obtain the density of STAs belonging to the same Wi-Fi network as the STA, which further includes:

[0018] The activity level of STAs belonging to the same Wi-Fi network is obtained, and then the obtained density value is adjusted according to the activity level.

[0019] Optionally, the formula for calculating the conflict cost time based on the STA density is specifically as follows:

[0020] The conflict cost time

[0021] Among them, collision probability The collision probability P represents the probability that a collision will occur when STAs send messages simultaneously.

[0022] num: The range of values ​​for the random number; currently a variable.

[0023] a: The density of STA;

[0024] V: The rate at which data packets are sent, which is a packet sending speed value defined by the STA;

[0025] L: The length of the data packet, which is obtained by the STA after analyzing the data packet to be sent.

[0026] Optionally, the formula for calculating the idle waiting time based on the STA density is specifically as follows:

[0027] Idle waiting time

[0028] a: The density of STA;

[0029] num: The range of values ​​for the random number, currently a variable.

[0030] Optionally, the specific implementation method for obtaining the range of random numbers when the estimated packet sending time is at its minimum is as follows:

[0031] The range of values ​​for the random number is obtained by traversal, so that the estimated packet sending time is minimized;

[0032] Alternatively, by differentiating the packet sending estimated time calculation function, the range of random number values ​​when the slope of the function is at its minimum can be obtained.

[0033] On the other hand, a method for a site to send data is provided, the method comprising:

[0034] When the STA needs to send data to the wireless access point AP using WIFI, the STA detects the current state of the spatial electromagnetic waves;

[0035] If the current state of the spatial electromagnetic wave is detected as idle, the data is sent directly.

[0036] If the current state of the spatial electromagnetic wave is detected as busy, the STA presets a waiting time until the waiting time is reached before sending the data.

[0037] Wherein, the waiting time = Distributed Coordination Frame Interval (Difs) time + Backoff time (time), and the backoff time (time) is calculated by the above method.

[0038] On the other hand, a site is provided, the site comprising:

[0039] An identification module is used to identify the STA density of the WIFI network to which the STA belongs;

[0040] The first calculation module is used to calculate the conflict cost time based on the STA density;

[0041] The second calculation module is used to calculate the idle waiting time based on the STA density;

[0042] The acquisition module is used to acquire the range of random numbers when the estimated packet sending time is at its minimum value, wherein the estimated packet sending time is the sum of the conflict cost time and the idle waiting time;

[0043] The third calculation module is used to calculate the rollback time based on the range of values ​​for the random number.

[0044] Optionally, the formula used by the first calculation module is as follows:

[0045] The conflict cost time

[0046] Among them, collision probability The collision probability P represents the probability that a collision will occur when STAs send messages simultaneously.

[0047] num: The range of values ​​for the random number; currently a variable.

[0048] a: The density of STA;

[0049] V: The rate at which data packets are sent, which is a packet sending speed value defined by the STA;

[0050] L: The length of the data packet, which is obtained by the STA after analyzing the data packet to be sent;

[0051] The formula used by the second calculation module is as follows:

[0052] Idle waiting time

[0053] a: The density of STA;

[0054] num: The range of values ​​for the random number, currently a variable.

[0055] The beneficial effects of the technical solution provided by this invention include at least the following:

[0056] This invention can dynamically and adaptively adjust the rollback time, reducing the long waiting time caused by resource waste in some practical application scenarios. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a flowchart of a dynamic adaptive adjustment method for backoff time provided in an embodiment of the present invention;

[0059] Figure 2 This is a site block diagram provided in an embodiment of the present invention. Detailed Implementation

[0060] like Figure 1 As shown, this embodiment of the invention provides a dynamic adaptive adjustment method for backoff time, the method comprising:

[0061] S1. Identify the STA density of the WIFI network to which the STA belongs;

[0062] S2. Calculate the conflict cost time based on the STA density;

[0063] S3. Calculate the idle waiting time based on the STA density;

[0064] S4. Obtain the range of random numbers when the estimated packet sending time is at its minimum, wherein the estimated packet sending time is the sum of the conflict cost time and the idle waiting time;

[0065] S5. Calculate the rollback time based on the range of the random number values.

[0066] The following describes in detail a dynamic adaptive adjustment method for backoff time according to an embodiment of the present invention.

[0067] The basic principle of this invention:

[0068] The STA can identify the STA density of its Wi-Fi network and dynamically adjust the range of random numbers.

[0069] When the STA density is relatively small, the range of random number values ​​is the smallest. As the STA density increases, this range of values ​​is dynamically and gradually expanded.

[0070] The method includes:

[0071] S1. Identify the STA density of the WIFI network to which the STA belongs;

[0072] The STA density is the number of STAs connected to the Wi-Fi network.

[0073] Optionally, when the STA first accesses the wireless access point AP, the STA identifies the STA density of the WIFI network to which the STA belongs;

[0074] Or the STA density of the WIFI network to which the STA periodically identifies the site;

[0075] Alternatively, if the number of collisions encountered by the STA exceeds a preset value, the STA identifies the STA density of the WIFI network to which the STA belongs.

[0076] When the number of collisions encountered by the STA exceeds a preset value, it indicates that the number of STAs in the WIFI network to which the STA belongs may have increased significantly. In this case, the STA identifies the STA density of the WIFI network to which the STA belongs.

[0077] Optionally, the STA identification site STA's STA density in the WIFI network includes:

[0078] The STA requests the AP to obtain the density of STAs belonging to the same WIFI network as the STA;

[0079] That is, to obtain the number of STAs that need to send data within the same time period.

[0080] Alternatively, the STA may probe to obtain the density of STAs belonging to the same Wi-Fi network.

[0081] That is, to obtain the number of STAs that need to send data within the same time period.

[0082] Specifically, requesting the STA density from the AP can be implemented in the following ways: when the number of devices mounted on the AP changes, the AP broadcasts the number of currently connected STAs; or the AP periodically broadcasts the number of STAs it has mounted.

[0083] Optionally, while requesting the STA density from the AP, the activity level of the STA will also be obtained, and the obtained density value will be automatically adjusted according to the activity level.

[0084] For example, if the data returned by the AP is A, and half of the devices hardly send any packets, then the density value can be adjusted to...

[0085] Optionally, the specific implementation of the STA listening to the STA density can be: continuously listening to the interactive messages it can hear, discovering new devices, recording the MAC address of the new devices, and updating the record table.

[0086] You can also obtain average data by comparing the data obtained from both the number of requests and the number you find out yourself.

[0087] S2. Calculate the conflict cost time based on the STA density;

[0088] Optionally, the formula for calculating the conflict cost time based on the STA density is specifically as follows:

[0089] The conflict cost time

[0090] Among them, collision probability The collision probability P represents the probability that a collision will occur when STAs send messages simultaneously.

[0091] num: The range of values ​​for the random number; currently a variable.

[0092] a: The density of STA;

[0093] V: The rate at which data packets are sent, which is a packet sending speed value defined by the STA;

[0094] L: The length of the data packet, which is obtained by the STA after analyzing the data packet to be sent.

[0095] This formula is just one example of an embodiment of the present invention. Other formulas can also be used to calculate the conflict cost time. The present invention does not limit the specific formulas, and they are all within the protection scope of the present invention.

[0096] S3. Calculate the idle waiting time based on the STA density;

[0097] Optionally, the formula for calculating the idle waiting time based on the STA density is specifically as follows:

[0098] Idle waiting time

[0099] a: The density of STA;

[0100] num: The range of values ​​for the random number, currently a variable.

[0101] This formula is just one example of an embodiment of the present invention. Other formulas can also be used to calculate the idle waiting time. The present invention does not limit the specific formula, and all of them are within the protection scope of the present invention.

[0102] S4. Obtain the range of random numbers when the estimated packet sending time is at its minimum, wherein the estimated packet sending time is the sum of the conflict cost time and the idle waiting time;

[0103] Therefore, the estimated packet sending time TIME_min = conflict cost time time_waste + idle waiting time time_idle;

[0104] The estimated packet sending time TIME_min will first decrease and then increase as num increases, adjusting the value of num. When TIME_min reaches its minimum value, the variable num will take the value of NUM1.

[0105] Optionally, the specific implementation method for the STA to obtain the range of random numbers when the estimated packet sending time is at its minimum is as follows:

[0106] The range of values ​​for the random number is obtained by traversal, so that the estimated packet sending time is minimized;

[0107] Alternatively, by differentiating the packet sending estimated time calculation function, the range of random number values ​​when the slope of the function is at its minimum can be obtained.

[0108] S5. Calculate the rollback time based on the range of the random number values.

[0109] The random number RND = un iform(0,NUM) is a random number generation function that generates a random number uniformly distributed in (0,NUM). When NUM = NUM1, the estimated packet sending time is minimized. NUM1 is the optimal value used to calculate the dynamic rollback time. Therefore, the rollback time time = Cw * un iform(0,NUM1) is calculated based on NUM1.

[0110] This invention also provides a method for a site to send data, the method comprising:

[0111] When the STA needs to send data to the wireless access point AP using WIFI, the STA detects the current state of the spatial electromagnetic waves;

[0112] If the current state of the spatial electromagnetic wave is detected as idle, the data is sent directly.

[0113] If the current state of the spatial electromagnetic wave is detected as busy, the STA presets a waiting time until the waiting time is reached before sending the data.

[0114] Wherein, the waiting time = Distributed Coordination Frame Interval (Difs) time + Backoff time (time), and the backoff time (time) is determined by the above. Figure 1 The calculation is obtained using the method in the corresponding embodiment.

[0115] like Figure 2 As shown, this embodiment of the invention also provides a site, the site comprising:

[0116] The identification module 210 is used to identify the STA density of the WIFI network to which the STA belongs;

[0117] The first calculation module 220 is used to calculate the conflict cost time based on the STA density;

[0118] The second calculation module 230 is used to calculate the idle waiting time based on the STA density;

[0119] The acquisition module 240 is used to acquire the range of random numbers when the estimated packet sending time is at its minimum value, wherein the estimated packet sending time is the sum of the conflict cost time and the idle waiting time;

[0120] The third calculation module 250 is used to calculate the rollback time based on the range of values ​​of the random number.

[0121] Optionally, the identification module is used to identify the STA density of the WIFI network to which the STA belongs when the STA first accesses the wireless access point AP; or to periodically identify the STA density of the WIFI network to which the STA belongs; or to identify the STA density of the WIFI network to which the STA belongs when the number of collisions encountered by the STA exceeds a preset value.

[0122] Optionally, the identification module is used to request the AP to obtain the density of STAs belonging to the same WIFI network as the STA, or for the STA to eavesdrop and obtain the density of STAs belonging to the same WIFI network, that is, to obtain the number of STAs that need to send data within the same time period.

[0123] Optionally, the identification module, while requesting the STA density from the AP, will also obtain the activity level of the STAs, and then adjust the obtained density value accordingly. For example, if the data returned by the AP is A, and half of the devices in A are basically not sending packets, then the density value can be adjusted to...

[0124] Optionally, the formula used by the first calculation module is as follows:

[0125] The conflict cost time

[0126] Among them, collision probability The collision probability P represents the probability that a collision will occur when STAs send messages simultaneously.

[0127] num: The range of values ​​for the random number; currently a variable.

[0128] a: The density of STA;

[0129] V: The rate at which data packets are sent, which is a packet sending speed value defined by the STA;

[0130] L: The length of the data packet, which is obtained by the STA after analyzing the data packet to be sent;

[0131] The formula used by the second calculation module is as follows:

[0132] Idle waiting time

[0133] a: The density of STA;

[0134] num: The range of values ​​for the random number, currently a variable.

[0135] The acquisition module is used to adjust the value of num according to the formula: estimated packet sending time TIME_min = conflict cost time time_waste + idle waiting time time_idle; the estimated packet sending time TIME_min will first decrease and then increase as num increases; when TIME_min reaches its minimum value, the acquisition module obtains the value NUM1 of the variable num, which is the required range of random numbers.

[0136] The third calculation module 250 calculates the rollback time based on the obtained NUM1 value.

[0137] Specifically, the random number RND = unifform(0,NUM) is a random number generation function that generates a random number uniformly distributed in (0,NUM). When NUM = NUM1, the estimated packet sending time is minimized. NUM1 is the optimal value used to calculate the dynamic rollback time. The third calculation module calculates the rollback time time = Cw * unifform(0,NUM1) based on NUM1.

[0138] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic adaptive adjustment method for backoff time, characterized in that, The method includes: Identify the STA density of the Wi-Fi network to which the STA belongs; The conflict cost time is calculated based on the STA density, and the specific formula for calculating the conflict cost time based on the STA density is as follows: The conflict cost time ; Among them, collision probability The collision probability P represents the probability that a collision will occur when STAs send messages simultaneously. num: The range of values ​​for the random number; currently a variable. a: The density of STA; V: The rate at which data packets are sent, which is a packet sending speed value defined by the STA; L: The length of the data packet, which is obtained by the STA after analyzing the data packet to be sent; The idle waiting time is calculated based on the STA density, and the specific formula for calculating the idle waiting time based on the STA density is as follows: Idle waiting time ; a: The density of STA; num: The range of values ​​for the random number; currently a variable. The method for obtaining the range of random numbers when the estimated packet sending time is at its minimum is as follows: The estimated packet sending time is the sum of the conflict cost time and the idle waiting time. The range of values ​​for the random number is obtained by traversal, so that the estimated packet sending time is minimized; Alternatively, by differentiating the packet sending estimated time calculation function, the range of random numbers when the slope of the function is at its minimum can be obtained. The rollback time is calculated based on the range of random number values.

2. The method according to claim 1, characterized in that, When the STA first connects to the wireless access point AP, the STA identifies the STA density of the WIFI network to which the STA belongs; Or the STA density of the WIFI network to which the STA periodically identifies the site; Or, if the number of times the STA encounters a conflict exceeds a preset value, the STA identifies the STA density of the WIFI network to which the STA belongs.

3. The method according to claim 1, characterized in that... The density of STAs in the Wi-Fi network to which the identified STA belongs specifically includes: The STA requests the AP to obtain the density of STAs belonging to the same WIFI network as the STA; Alternatively, the STA may probe to obtain the density of STAs belonging to the same WIFI network.

4. The method according to claim 3, characterized in that... The STA requests the AP to obtain the density of STAs belonging to the same WIFI network as the STA, and also includes: The activity level of STAs belonging to the same WIFI network is obtained, and then the obtained density value is adjusted according to the activity level.

5. A method for a station to send data, characterized in that, The method includes: When the STA needs to send data to the wireless access point AP using WIFI, the STA detects the current state of the spatial electromagnetic waves; If the current state of the spatial electromagnetic wave is detected as idle, the data is sent directly. If the current state of the spatial electromagnetic wave is detected as busy, the STA presets a waiting time until the waiting time is reached before sending the data. Wherein, the waiting time = Distributed Coordination Frame Interval (DIFS) time + Backoff time time, and the backoff time time is calculated by the method described in any one of claims 1-4.

6. A site, characterized in that, The sites include: The identification module is used to identify the STA density of the WIFI network to which the STA belongs; The first calculation module is used to calculate the conflict cost time based on the STA density. The formula used by the first calculation module is as follows: The conflict cost time ; Among them, collision probability The collision probability P represents the probability that a collision will occur when STAs send messages simultaneously. num: The range of values ​​for the random number; currently a variable. a: The density of STA; V: The rate at which data packets are sent, which is a packet sending speed value defined by the STA; L: The length of the data packet, which is obtained by the STA after analyzing the data packet to be sent; The second calculation module is used to calculate the idle waiting time based on the STA density. The formula for calculating the idle waiting time based on the STA density is as follows: Idle waiting time ; a: The density of STA; num: The range of values ​​for the random number; currently a variable. The acquisition module is used to acquire the range of random numbers when the estimated packet sending time is at its minimum value, wherein the estimated packet sending time is the sum of the conflict cost time and the idle waiting time; The third calculation module is used to calculate the rollback time based on the range of random number values. The specific implementation method for obtaining the range of random number values ​​when the estimated packet sending time is at its minimum is as follows: The range of values ​​for the random number is obtained by traversal, so that the estimated packet sending time is minimized; Alternatively, by differentiating the packet sending estimated time calculation function, the range of random number values ​​when the slope of the function is at its minimum can be obtained.

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