Method for configuring rate adaptation and device with wireless capability

Abstract

In one embodiment, a method of configuring rate adaptation of data transmissions and a wirelessly enabled apparatus, the method comprising: for a first phase: transmitting a set of test data packets; and determining a first rate adaptation configuration based on feedback corresponding to the transmission of the set of test data packets; for a second stage: transmitting a set of application data packets according to the first rate adaptation configuration; and determining a second rate adaptation configuration based on at least one of the transmission of the set of test packets or the transmission of the set of application packets.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to a method for configuring rate adaptation in wireless communications and a device with wireless capabilities. Background Art

[0002] Reducing latency for predictable traffic is critical to ensuring reliable communications and enhancing Quality of Service (QoS). In wireless systems based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11, unlicensed spectrum is used for wireless communications. Contention in the shared wireless spectrum can result in excessive latency. Managing the latency of predictable data packets is critical to meeting the QoS requirements of a certain class of time-sensitive applications.

[0003] Therefore, a suitable transmission scheme may be proposed to avoid the long convergence time of the next generation IEEE 802.11 communication. Summary of the invention

[0004] In one embodiment, a method for configuring rate adaptation of data transmission includes: for a first stage: sending a group of test data packets; and determining a first rate adaptation configuration based on feedback corresponding to the sending of the group of test data packets; for a second stage: sending a group of application data packets according to the first rate adaptation configuration; and determining a second rate adaptation configuration based on at least one of the sending of the group of test data packets or the sending of the group of application data packets.

[0005] These and other aspects of the invention will become apparent upon reading the embodiments described hereinafter and will be explained with reference to the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Many aspects of the embodiments of the present invention may be better understood with reference to the following illustrative drawings. The components in the drawings are not necessarily drawn to scale, but emphasis is placed on clearly illustrating the principles of the embodiments of the present invention. In addition, in the drawings, the same reference numerals designate corresponding parts in several views.

[0007] Figure 1 is a schematic diagram showing an exemplary two-stage rate adaptation method according to an embodiment of the present invention;

[0008] Figure 2A It is shown that according to an embodiment of the present invention, using Figure 1A schematic diagram of an exemplary expected transmission pattern of the two-stage rate adaptation method shown;

[0009] Figure 2B is an example of an embodiment according to the present invention, from Figure 2A A diagram showing an enlarged view of one of the test data packet transmissions plus application data packet transmissions of the intended transmission and certain parameters;

[0010] Figure 3 is an example of an embodiment according to the present invention, from Figure 2A A schematic diagram of some parameters of a test data packet transmission plus an enlarged view of one of the application data packet transmissions of an expected transmission mode in which the pre-transmission is delayed due to a busy channel;

[0011] Figure 4 It is shown that according to an embodiment of the present invention, using Figure 1 A schematic diagram of an exemplary signaling flow of downlink data transmission controlled by an access point (AP) showing a two-stage rate adaptation method;

[0012] Figure 5A It is shown that according to an embodiment of the present invention, using Figure 1 A schematic diagram of an exemplary signaling flow of uplink data transmission controlled by an AP showing a two-stage rate adaptation method;

[0013] Figure 5B is a diagram showing an embodiment of the present invention Figure 5A A schematic diagram of a variation of the illustrated exemplary signaling flow;

[0014] Figure 6 It is shown that according to an embodiment of the present invention, using Figure 1 A schematic diagram of an exemplary signaling flow of uplink data transmission controlled by a station (STA) showing a two-stage rate adaptation method;

[0015] Figure 7 is a schematic diagram showing an exemplary signaling flow of a pre-data transmission phase and a subsequent application data packet transmission phase using a plurality of different modulation coding schemes (MCS) according to an embodiment of the present invention;

[0016] Figure 8 It is a diagram showing various devices that can be implemented according to an embodiment of the present invention. Figure 1 A schematic diagram of an exemplary communication system showing a two-stage rate adaptation method;

[0017] Fig. 9 It is shown that according to an embodiment of the present invention, Figure 8 A schematic diagram of an exemplary computing architecture of a wireless-enabled device used in the communication system;

[0018] Fig.10 is a flow chart illustrating an exemplary two-stage rate adaptation method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] Certain embodiments of a two-stage rate adaptation method (and apparatus and systems in which the method may be implemented) that may improve the reliability and / or timeliness of certain wireless transmissions are disclosed. In one embodiment, the two-stage rate adaptation method provides a rate adaptation configuration based on a set of test data packets sent during a pre-data transmission phase and based on application data packets subsequently sent during a data transmission phase, wherein the rate adaptation configuration for the data transmission is based on the test data packets, the application data packets, or a combination of the test data packets and the application data packets.

[0020] Without further ado, rate adaptation (or sometimes referred to as link adaptation) is a mechanism for selecting a transmission rate based on current channel quality (eg, based on wireless channel conditions) in wireless systems based on IEEE 802.11. Existing wireless-capable devices using the rate adaptation mechanism of an IEEE 802.11-based wireless system transmit application data packets and use a rate adaptation module that adjusts the rate and other transmission parameters (e.g., modulation and coding scheme (MCS) (e.g., Binary Phase Shift Keying (BPSK) 1 / 2, Quadrature Phase Shift Keying (QPSK) 3 / 4, etc.), guard interval (e.g., Orthogonal Frequency Division Multiplexing (OFDM) guard interval setting), spatial streams (e.g., multiple-in, multiple out (MIMO) configuration, channel bandwidth, etc.)) based on channel conditions determined based on a response to the transmission (e.g., a response (e.g., acknowledgment (ACK)) or the absence of the response from a receiving device. For example, the MCS table is publicly available, such as on the website SemFio network (e.g., https: / / semfionetworks.com / blog / wi-fi-7-mcs-table / )or https: / / mcsindex.net / (here are just a few examples). As a simple example, if the channel quality is determined to be good, a high transmission rate can be used, and if the channel quality is determined to be poor, a lower, more robust transmission rate can be used. Although there are other algorithms, a common rate adaptation algorithm is Minstrel. In fact, existing systems and methods configure rate adaptation based on feedback from data transmission, and then adjust the rate through several rounds of trial and error. For certain applications (for example, certain office environments (e.g., emergency response centers, gas utility service facilities, etc.) where high reliability and / or low latency of data transmission within a wireless local area network (WLAN) communication system are critical, or smart environments (e.g., robotic applications in smart factories / smart manufacturing settings or medical facilities) and other applications involving high priority transmission), this approach may not be desirable. In contrast, certain embodiments of the two-stage rate adaptation method can achieve the desired rate adaptation configuration and / or accelerate the rate adaptation convergence time before actually delivering the application data packet to improve the reliability and / or timeliness of wireless transmission. By applying the two-stage rate adaptation method, it is possible to reduce the rate adaptation convergence time and / or the waiting time for wireless channel access.

[0021] Having summarized certain features of the two-stage rate adaptation method of the present disclosure, reference will now be made in detail to the description of the two-stage rate adaptation method as shown in the accompanying drawings. Although the two-stage rate adaptation method will be described in conjunction with these drawings, it is not intended to limit the two-stage rate adaptation method to one or more embodiments disclosed herein. For example, an exemplary implementation using three transmission rounds (e.g., one round including one or more test data packets during pre-data transmission, one round including corresponding pre-data transmission results, and one round including one or more application data packets sent during data transmission) is shown, but it should be understood that different numbers (fewer or more) of transmission rounds may also be implemented and are therefore contemplated to be within the scope of the present invention. In addition, certain embodiments of the two-stage rate adaptation method are described or illustrated herein using a periodic transmission mode. However, it should be understood within the context of the present disclosure that the data transmission mode contemplated herein, whether periodic, predictable, and / or having a known or historical pattern, can generally be in the form of an expected data transmission mode. In addition, although the focus is on a wireless communication system environment implemented as an office-based WLAN environment in one example (where one or more APs serve multiple wireless-capable devices (e.g., laptops, tablets, phones, etc.)), some examples of applications to various smart environments are also described below (e.g., smart factories, hospitals, or research facilities where dedicated wireless-capable devices (e.g., robots) can be used). In other words, it should be understood by a person of ordinary skill in the art that, in the context of the present disclosure, certain embodiments of the two-stage rate adaptation method can be used in various types of environments where the reliability and timeliness of data packet transmission are critical, and are therefore contemplated to be within the scope of the present disclosure. In addition, although the present description identifies or describes specific details of one or more embodiments, such specific details are not necessarily part of each embodiment, nor are they necessarily all of the various stated advantages that are necessarily associated with a single embodiment. Instead, the purpose is to cover alternatives, modifications, and equivalent forms included within the principles and scope of the embodiments of the present disclosure as defined by the appended claims. For example, two or more embodiments may be interchangeable or combined in any combination. In addition, it should be understood that in the context of the present disclosure, the claims are not necessarily limited to the specific embodiments set forth in the present description.

[0022] In continuing Figure 1Before proceeding, a general overview of the challenges in 802.11-based wireless communications is described. As the quality of the wireless channel changes, a link (or similarly, rate) adaptation mechanism is applied. As described above, a set of transmission configuration schemes (e.g., including modulation schemes and coding schemes) are defined in a wireless communication system. Based on the quality of the wireless link and / or the previous data transmission success / failure history, the wireless communication device can use a rate adaptation mechanism to select a suitable transmission configuration. In some systems, an ACK-based rate adaptation mechanism (e.g., Minstrel) can be applied to wireless communications based on IEEE802.11. Since the ACK-based rate adaptation mechanism relies on previous successful / failed data reception and corresponding ACK messages, a suitable transmission scheme can be selected after several rounds of data transmission, which can result in a long convergence time. The long convergence time of rate adaptation can result in reduced channel utilization and / or high transmission errors.

[0023] To illustrate one way to address one or more of these or other challenges, we turn our attention to Figure 1 . Figure 1 An embodiment of an exemplary two-stage rate adaptation method 10 is shown. Fig. 9 The two-stage rate adaptation method 10 is implemented on a WLAN device (e.g., a WLAN access point, a WLAN station, a WLAN router, and / or a hotspot device) in a wireless (802.11-based) communication system as shown in FIG. 1 and explained below. Figure 1 1 and 2. Rate adaptation is performed in two phases, shown as phase 1 rate adaptation 12 (RA(PHS1)) and phase 2 rate adaptation 14 (RA(PHS2)). Phase 1 is also referred to herein as a pre-data transmission phase, and phase 2 is also referred to herein as a data transmission phase. During phase 1, a set of test data packets are sent (operation 16) to enable the transmitting device to perform rate adaptation based on feedback (e.g., for testing a better rate adaptation configuration (e.g., MCS setting, MIMO configuration, etc.) for subsequent data transmission in the upcoming phase 2). The set of test data packets may be data packets with an empty data payload or data packets with a small dummy data payload (e.g., an unimportant or meaningless data packet payload), wherein the sending 16 of the test data packets is intended to derive a transmission result 18 (e.g., may include receiving an ACK or not receiving an ACK (transmission result TX RSLT)) that can be used to determine the rate adaptation configuration. Reference to a set of test data packets (or a set of application data packets) herein may include a single packet or multiple packets.

[0024] After the phase 1 rate adaptation 12 (and feedback associated with the transmission results 18), the data transmission phase 20 begins, and specifically the phase 2 rate adaptation 14 is initiated / started. In the phase 2 rate adaptation 14, according to the rate adaptation performed in phase 1 and / or after feedback associated with receiving the transmission results 24 (e.g., TX RSLT, which may include the presence or absence of ACK) (i.e., which may be further adjusted based on the transmission results 24), an application data packet (e.g., having a meaningful packet data payload) is sent (operation 22). In one embodiment, the application data packet includes reliable (e.g., ultra-reliable) and / or low-latency application data. In some embodiments, the application data packet may include a control message for controlling another device. The data transmission 22 in phase 2 (including one or more application data packets) may be based on rate adaptation configured according to a test data packet sent in phase 1, an application data packet sent in phase 2, or a combination of test data packets and application data packets from phases 1 and 2. Transmitting the application data packets completes a round of data transmission 26, which may generate a record 28 of the rate adaptation configuration (from the previous round of transmission) for use in the next round of data transmission according to the phase 1 rate adaptation configuration and the phase 2 rate adaptation configuration.

[0025] As a brief digression and as briefly explained above, in existing 802.11 wireless communications, rate adaptation is performed only during the data transmission phase. For example, a WLAN device configured with rate adaptation logic (e.g., a module) may send (transmit) a plurality of packets (e.g., five (5) packets) and receive transmission results (e.g., ACK or no response depending on channel conditions) for the corresponding transmitted packets. Based on the transmission results, the WLAN device may adjust the MCS, rate, etc. In contrast, certain embodiments of the two-stage rate adaptation method configure rate adaptation using two stages (stage 1 and stage 2). For example, when an important transmission is expected (e.g., to control a robot, a laptop / tablet computer, or a mobile phone), stage 1 rate adaptation 12 is added to the existing rate adaptation method, wherein in a stage that may also be referred to as a trial stage, a test data packet (e.g., with an empty payload or a dummy payload) is initially sent 16 to the stage 2 application data packet transmission 22. These test data packets 16 enable the transmitting WLAN device to adapt to a more appropriate scheme before the data transmission phase (phase 2) based on the transmission results 18. It is worth noting that the phase 1 rate adaptation 12 and the phase 2 rate adaptation 14 are implemented in the same WLAN device, for example via a rate adaptation module / logic (e.g., software and / or hardware). As explained above, the test data packets can be regarded as unimportant packets (e.g., not used to control devices such as robots, laptops / tablets or mobile phones), but can be artificially generated and have empty or dummy (meaningless) payload data. Based on the transmission results 18 (e.g., based on the receipt or non-receipt of an ACK from the receiving device), the rate adaptation function in the transmitting WLAN device adjusts to a suitable rate adaptation configuration (e.g., a suitable MCS scheme for channel conditions, different rates, etc.), and then the data transmission phase 20 is initiated, in which application data packets (e.g., in some cases, important device control packets) are sent 22 (and wherein the rate adaptation can be adjusted again based on the transmission results 24). At the end of the data transfer phase 26 (the round is completed), the two-stage rate adaptation method 10 itself is repeated.

[0026] Figure 2A An example expected (eg, periodic) transmission pattern 30 using the two-stage rate adaptation method 10 is shown. The expected transmission pattern 30 is illustrated using four (4) rounds of data transmission. For example (and continuing with reference to Figure 1 ),from Figure 2A, a bold block corresponding to the transmission 16 of a set of test packets based on stage 1 rate adaptation 12 is shown, and adjacent to the bold block is another (non-bold) block representing the transmission 22 of a set of application packets based on stage 2 rate adaptation 14. The first two blocks labeled 16 and 22 represent a first round of data transmission (e.g., including the set of application packets and the set of test packets), and a subsequent group of similarly labeled bold / non-bold blocks to the right of the first group of blocks along the time axis represent subsequent multiple rounds of data transmission, a total of four (4) rounds of data transmission in this example. Also shown above the blocks and approximately aligned with the start of the transmission of the application packets are annotations illustrating the expected arrival time (e.g., of the application packets) from another device. The annotation includes an arrow and a corresponding label tx, where x=1, 2, 3 or 4, and illustrates the expected arrival time of an application data packet (e.g., an application data packet from a computer, a controller or an AP) at a WLAN device before being sent (sent at or near the arrival time) to communicate with (and control) another device (e.g., a laptop computer, a robot, etc.)

[0027] To further illustrate, consider an exemplary scenario in which the application environment is an office having multiple distributed APs / routers controlled by a controller (e.g., a host computer or server) and multiple wireless-capable devices (e.g., laptop computers), wherein the multiple distributed APs / routers can communicate with the multiple laptop computers by transmitting commands with application data packets via a wired / wireless WLAN. In some examples, all devices in the wired / wireless WLAN can include control algorithms, and thus there is no expected delivery of commands relayed to the wireless-capable devices (e.g., laptop computers) at or about the delivery time. It is further assumed that the purpose is to periodically communicate with, for example, the laptop computer via corresponding rounds of four (4) data transmission rounds (e.g., updating the laptop computer every 100 milliseconds (msec)), wherein the first round starts at or near t1, the second round starts at or near t2, the third round starts at or near t3, and the fourth round starts at or near t4. For example, in practice, a notebook computer may receive an application data packet (e.g., a command) at or near t1, take action, and then there is a delay while the notebook computer reacts, and then receives (and transmits) the next command (t2), and so on, to implement a given control method. The ability to transmit commands (application data packets 22) in a reliable and timely manner ensures effective control and action (e.g., in a time-sensitive manner). In addition, it is critical that the notebook computer maintains such timely and reliable operation in the middle of different channel conditions and converges quickly to a suitable rate adaptation (e.g., without the material delays encountered during long trial and error). According to certain embodiments of the two-stage rate adaptation method, each transmission round involves two rate adaptation stages (stage 1 and stage 2). In one embodiment, in the first stage (stage 1), according to the pre-data transmission stage, the corresponding set of test data packets are sent at a time immediately before the corresponding expected arrival time (e.g., t1, t2, t3, and t4) to enable preliminary adjustment of rate adaptation before starting the corresponding application data packet transmission. It should be noted that the examples given above can be replaced by a notebook computer using, for example, a robot with similar effects.

[0028] Figure 2BA zoomed in view of the (sent) set of test data packets 16 plus the set of application data packets 22 and some important parameters is shown. In general, the pre-data transmission phase (phase 1) including the transmission of the set of test data packets may have a duration equal to T_pre. In one scenario, given an expected (e.g., periodic) arrival (and data transmission phase start) time of t_i, each pre-data transmission phase may start at (t_i-T_pre) before the arrival time. For an example where the pre-data transmission phase starts on time, a simple example helps to illustrate this mechanism. If the application data transmission 22 (phase 2) is to be started at 10 milliseconds and the pre-data transmission is configured to run for a duration of 1 millisecond, the pre-data transmission phase (phase 1) should run from 9 milliseconds to 10 milliseconds.

[0029] Figure 2B Some additional configuration parameters are also shown. For example, the downward arrow 31 in the box corresponding to the pre-data transmission phase represents the number of pre-data packets or test packets (e.g., two in this example, although other numbers (including 3, 5, etc.) may also be used). The configuration may also include one or more parameters that can be used to configure a suitable (e.g., improved or optimal) MCS during the pre-data transmission phase (phase 1), and include one or any combination of the following: T_pre, (t_i-T_pre), the number of test packets, the time gap between test packets, and the size (e.g., bytes) of each test packet or the total size.

[0030] Despite FIG. 2A to FIG. 2B The corresponding examples are based on a pre-data transmission phase that starts on time (as expected, e.g., starting at a time T_pre before the arrival time t), but there are instances where the pre-data transmission time may be postponed (or terminated early as described below). For example, the pre-data transmission time may be postponed due to a busy channel (e.g., where transmissions by nearby channel contention wireless devices are not completed). Figure 3 Shown from Figure 2A A test data packet transmission of the intended transmission pattern is shown, plus a zoomed in view of one of the application data packet transmissions and certain parameters, where the pre-data packet transmission is delayed due to a busy channel. As is well known, wireless transmissions (e.g., transmissions compliant with IEEE 802.11) use shared channels where multiple devices use the same frequency spectrum. Therefore, there may be contention among the devices for the same channel to temporarily occupy the channel. Although Figure 2A The expected start time for starting the pre-data transfer phase is shown, but it should be remembered that other devices may be using the channel. Figure 3The latter case is shown as channel busy time 32. Channel busy time 32 may, for example, extend from a neighboring WLAN device with an uncompleted transmission to (encroach upon) the previously described ( Figure 2B ) is a pre-data transmission phase start time of (t_i-T_pre) and exceeds the pre-data transmission phase start time. In current standards (e.g., IEEE 802.11), ongoing channel transmissions are not interrupted. To avoid conflicts or transmission failures, the start time (t_i-T_pre) should be postponed until the channel is no longer busy (e.g., neighboring WLAN devices stop transmitting). In this example, the pre-data transmission start time is postponed by a certain amount of time 34 due to the channel busy time 32. Since it is critical that application data packets are delivered 22 as expected (e.g., delivered at t_i so that, for example, notebook computers (or robots, etc.) receive their commands on time), the duration of the pre-data transmission is increased from T_pre ( Figure 2B ) becomes the adjusted (shortened) duration (T_pre(adjusted)). In other words, Figure 2B The pre-data transmission 16 shown is shortened to pre-data transmission 16a due to the delayed amount of time 34, resulting in the start of the pre-data transmission phase being delayed to (t_i-T_pre(adjusted)). Therefore, the start of the pre-data transmission period is delayed, but ends on time because the next data transmission (phase 2) should start as expected (t_i) to ensure the reliability and timeliness of application data packet delivery (e.g., to ensure that the notebook computer (or robot) receives their commands on time). Even if the channel busy time 32 shortens the pre-data transmission duration, the pre-data transmission is still used to find a better rate adaptation (e.g., MCS) for data transmission.

[0031] In practice, the expected start time of the pre-data transmission phase is configured, and when the channel is busy and encroaches on the pre-data transmission phase start time, the pre-data transmission start time is postponed in an effort to maintain the expected start time for sending the application data packet.

[0032] Since the expected data transmission time (start of phase 2) can be based on prediction, the WLAN device can receive the application data packet before the expected transmission is predicted to occur, so that the channel can be accessed earlier than expected. In such a scenario and in some embodiments, pre-emption can be used, where the pre-data transmission phase can be shortened (e.g., terminated early) to facilitate early delivery of the application data packet. In other words, the data transmission phase (phase 2) preempts the pre-data transmission phase (phase 1).

[0033] Having described the features of certain embodiments of the two-stage rate adaptation method, attention is now turned to Figures 4 to 8 , Figures 4 to 8 Various exemplary signaling flows for uplink (UL) implementation and downlink (DL) implementation using a two-stage rate adaptation method based on different control locations are shown. Each of the signaling flow diagrams shows at the top of the diagram at least one STA and an AP as a transmitting device and a receiving device of a wireless communication system. The AP may be a WLAN AP (e.g., an IEEE 802.11 AP), or a Wireless Fidelity (WiFi) router, or a notebook computer or phone acting as a hotspot and other devices. The station may be an IEEE 802.11 device, or more generally a WLAN device with an 802.11 WLAN radio interface, which may include a notebook computer, a laptop computer, a tablet computer, a mobile phone, or an IEEE 802.11 STA and other devices. It should be understood that in the context of the present disclosure, a WLAN device and / or a WLAN AP may include rate adaptation logic (e.g., a hardware module and / or a software module), wherein rate adaptation may be performed in two stages, as explained above. For example, rate adaptation can be performed in the pre-data transmission phase (phase 1), where pre-data packet transmission can be applied to test out a better rate adaptation configuration (e.g., MCS setting and / or MIMO configuration setting) for the upcoming data transmission. In addition, rate adaptation can then be performed in the data transmission phase (phase 2).

[0034] refer to Figure 4 , Figure 4 An exemplary signaling flow 36 of an AP-controlled downlink (DL) data transmission using an embodiment of a two-stage rate adaptation method is shown. As explained above, the AP may be an IEEE 802.11 access point (e.g., in ordinary use, it may be a hotspot in the home (e.g., a WiFi router in the home) or a laptop computer that functions as a hotspot). More specifically for one of the use cases described herein, the two-stage rate adaptation method may be implemented in more critical applications with higher reliability and / or latency standards (e.g., in an office environment or a smart environment). The station may be an 802.11 device (e.g., an 802.11 WLAN device). In the scenario shown here, the operation is initiated by the AP (i.e., controlled by the AP). Application data packets are transmitted from the AP to the STA. 36, the AP may optionally announce high quality DL service 38 (ANNOUNCE DL), which in this non-limiting example is followed by three (3) sets (or rounds) of data transmission (each round is distinguished by reference numbers such that a, b and c are sufficient to represent the first, second and third rounds).

[0035] As a brief digression, the AP is aware of the data traffic pattern and / or has the ability to configure the data traffic pattern. In the case where a computer / server or controller initiates and then sends a command to the AP, the data transmission is expected to arrive at the AP at a set of predetermined time points (which may include some minor delay variations), which can be reflected as periodic data traffic with a fixed time period between two data packets. In turn, the data traffic is expected to be transmitted from the AP to the STA. There are one or more different mechanisms in which the AP can obtain information about the expected data traffic pattern from a configuration message sent by an application server and / or from a configuration message sent by a WLAN controller based on the application type in the packet header, based on the address of the source node and / or the address of the destination node, based on the QoS type indicated in the packet header.

[0036] Continuing, in the first round, the AP transmits a pre-data transmission packet 40a (PRE-DATA TX). As explained above, when data packet P_i is expected to arrive at the AP at time t_i, the AP starts the pre-data transmission procedure before t_i. The start time can be configured as (t_i-T_pre), where T_pre is a configurable parameter of the protocol operation. In addition, the AP can start channel access contention at (t_i-T_pre), where the AP essentially strives to obtain the right to use the channel. If the channel contention is successful, the AP can become a transmission opportunity (TXOP) holder. During the TXOP duration, the AP has the right to transmit. Whenever the AP obtains the right to use the channel, this TXOP duration should cover the pre-transmission phase (phase 1) and the data transmission phase (phase 2) (while other devices cannot access the channel). The AP may send a set (one or more) of pre-data transmission packets, each of which may be configured as a data packet with a small dummy data payload, a data packet with an empty data payload, a null packet (e.g., a null data Physical Layer Protocol Data Unit (PPDU)), or a control packet requesting a channel state measurement (e.g., a sounding PPDU). The AP may transmit multiple pre-data transmission packets until the number of transmitted pre-data transmission packets is equal to the upper limit packet number N_max, the time for pre-data transmission is greater than or equal to the time threshold T_max, or the application data (which is predicted to arrive at time t_i) has arrived at the AP. In some embodiments, the AP may terminate the pre-data transmission phase (early) and start data transmission (e.g., preemption as explained above).

[0037] The station responds (or does not respond) with a transmission result 42a (TX RSLT). For example, the transmission result 42a may be an ACK and / or channel feedback. It should be noted that although the following is generally explained in the context of actually receiving an ACK, references to the transmission result in the following generally refer to using the presence or absence of an ACK as feedback to enable determination of a rate adaptation configuration. Sometimes, in a pre-data transmission, some channel measurements (e.g., an indication of channel quality) or feedback are provided, and the STA may send the some channel measurements or feedback to the AP. More specifically, the STA may respond with an ACK message upon receiving the pre-data transmission 40a, perform channel measurements and report channel state information to the AP, or respond with an ACK with piggybacked channel state information feedback (or as explained above, there may be examples of not receiving an ACK or other information, particularly in low-quality channels).

[0038] Based on 40a and 42a, the AP performs rate adaptation (e.g., adjusting the MCS, etc.), which is then used for (subsequent) data transmission 44a (DATA TX). For example, when the AP receives an ACK message and / or channel state information feedback from the STA, it can perform rate adaptation and select / reselect an appropriate transmission configuration (e.g., modulation or coding scheme).

[0039] The AP then transmits the set of application data packets during a data transmission phase 44a.

[0040] This overall process (40, 42 and 44) ​​is repeated in a similar manner for the second round of data transfer (40b, 42b and 44b) and then for the third round of data transfer (40c, 42c and 44c).

[0041] It should be noted that during the optional announcement 38 (high quality DL service message) before the pre-data transmission (transmission of the test data packet) 40a, the AP notifies the STA of certain characteristics of the subsequent multiple rounds of data transmission. For example, the announcement 38 may inform the STA that there will be multiple rounds (e.g., three (3) rounds in this example) of the two-phase transmission times. The announcement 38 may also inform the STA of the start time, the period of the transmission rounds, etc., so that the STA can know when to expect the pre-data transmission to start and when the data transmission starts. In addition, in combination with Figure 2B One or more of the parameters set forth (eg, duration of the pre-transmission phase, number of pre-transmission packets, etc.) may be configured within the announcement 38. In practice, the announcement 38 informs the STA of the rate adaptation configuration to be used in both phases (Phase 1 and Phase 2).

[0042] Figure 5A An example signaling flow 46A is shown for an AP-controlled uplink (UL) data transmission using an embodiment of a two-stage rate adaptation method. Figure 5B Show Figure 5A A variation of signaling flow 46A is shown and is designated as signaling flow 46B. Figure 5A The signaling flow 46A shown is Figure 4 The signaling flow 36 shown is similar. For example, the signaling flow 46A is still controlled by the AP. However, Figure 4 The data transmission is from STA to AP (UL transmission) compared to the data transmission from AP to STA (DL transmission) in FIG. 1 . Another similarity is that there are still three (3) rounds (although as explained above only as an illustrative example, a different number of rounds may be used in some embodiments) of two-phase transmission, each round having the same number of rounds as for the AP. Figure 4 Similar concepts are described in the rounds in . In AP-controlled uplink data transmission, data traffic is expected to be transmitted from STA to AP. It should be noted that uplink ultra-reliable applications with uplink data to be transmitted may be found in some mission-critical applications, where application data packets (e.g., alarm messages, sensing data, etc.) may need to be sent in a reliable and timely manner. The AP may be aware of the data traffic pattern, where data transmission is expected to arrive at the AP in a set of predetermined time points (possibly with some minor delay variations). For example, the data transmission may follow a periodic data traffic pattern with a fixed time period between two data packets. Similar to the above for Figure 4 In a similar manner to that described in the signaling flow 36, the AP may obtain information about the data traffic pattern in one or a combination of ways. For example, the AP may determine the policy by itself (e.g., the AP may be the source of the policy). In some embodiments, Figure 5B As reflected in the illustrated signaling flow 46B, the AP may receive a configuration message 62 (CNFG CMD) sent by the WLAN controller.

[0043] The AP may learn the data traffic pattern in other or additional ways. For example, the AP may learn the data traffic pattern from the request 48 sent by the STA. Figure 5AIn the signaling flow 46A shown, the STA sends a request for high quality uplink service (RQST UL) to the AP 48. This signaling message (request 48) informs the AP that in the next few rounds of data transmission, the STA expects to report important information and therefore requests configuration of this type of service. The STA informs the AP about the parameters of the expected traffic. For example, the STA can send this control message to establish a high quality service for a predictable uplink data traffic. The control message can include a set of time points for the expected transmission time, the expected size of each data packet, the period of the periodic service flow, the start time of this uplink data flow, the end time of this uplink data flow, and / or the number of data packets of the periodic data flow.

[0044] The AP responds to the STA with a configuration (CNFG UL) of the high quality uplink service 50. The configuration informs the STA about parameters such as the start time, the period, how long the pre-data transfer phase lasts, and so on.

[0045] Thereafter, in the first round of data transmission, the STA sends a set of test packets according to the pre-data transmission 52a (PRE-DATA TX in stage 1). When it is expected that a data packet P_i will be generated at the STA at time t_i, the STA starts the pre-data transmission procedure before t_i. The start time can be configured as (t_i-T_pre), where T_pre is a configurable parameter for protocol operation. The STA can start channel access contention at (t_i-T_pre). If the channel contention is successful, the STA can become the TXOP holder. The STA can transmit one or more pre-data transmission packets, and the pre-data transmission packets may include a data packet with a small dummy data payload, a data packet with an empty data payload, a null packet (e.g., a null data PPDU), or a control packet requesting channel state measurement (e.g., a sounding PPDU).

[0046] The transmission of the pre-data packet may result in a transmission result 54a (e.g., TX RSLT, which may be the presence or absence of ACK and / or channel feedback) from the AP (e.g., confirmation that the set of packets was successfully received). For example, upon receiving the pre-data transmission, the AP may respond with an ACK message and / or perform channel measurements and report channel state information to the STA. The AP may respond with an ACK with piggybacked channel state information feedback (or may not respond at all).

[0047] The STA performs rate adaptation (e.g., selects a better MCS, etc.) based on 52a and 54a. For example, upon receiving (or not receiving) an ACK message or / and channel state information feedback from the AP, the STA performs rate adaptation and selects / reselects an appropriate transmission configuration (e.g., MCS).

[0048] The STA sends a set of application data packets corresponding to data transmission 56a (DATA TX), which is based on rate adaptation performed on the basis of feedback from the sent test data packets. The STA may transmit multiple pre-data transmission packets until the number of pre-data transmission packets transmitted is equal to the upper limit packet number N_max, the time for pre-data transmission is greater than or equal to the time threshold T_max, the application data arriving at time t_i is predicted to have arrived at the STA WLAN wireless point interface, or the STA may terminate the pre-data transmission phase (in advance) and start data transmission. Through this process, application (phase 2) data transmission can be more reliable (compared to performing rate adaptation only during the data transmission phase). This two-stage rate adaptation is repeated again for the second round of data transmission (52b, 54b and 56b) and the third round of data transmission (52c, 54c and 56c) in a similar manner as the first round of data transmission.

[0049] As mentioned above, Figure 5B Show Figure 5A The signaling flow shown is a variation of the controller. From one perspective, Figure 5A The AP shown may have a Figure 5B The functions of the controller are shown in Figure 5B In the embodiment, the functions of the controller are performed by a device separate from the AP. An exemplary implementation environment may be an office or area where one or more APs cover / serve one or more wireless devices (e.g., laptops, tablets, phones, etc.), or a large factory where multiple APs exist to cover a large area. In addition, although the controller is physically separated from the AP, it is also physically separate from the AP. Figure 5A The basic operations described in the related description (eg, UL data transmission controlled by the AP, where the STA initiates the UL data transmission service) are for Figure 5B are generally the same, with some differences noted below. Figure 5B In the illustrated signaling flow 46B, a request for high quality uplink service 60 (RQST UL) is relayed by the AP to a controller (e.g., a WLAN controller within the network). The controller may control one or more access points. Request 60 may be similar to request 48 (RQST UL) in terms of content (e.g., parameters) and the information it provides to the AP. Figure 5A However, in this scenario, the controller uses the configuration command 62 (CNFG CMD) to transmit a configuration UL message 64 (CNFG UL) based on the configuration command 62, which is similar to the configuration UL message 64 (CNFG UL) in content and effect. Figure 5A The controller is actually the configuration source for this service, not the AP. Figure 5AThe AP-sourced configuration of the high-quality UL data transmission service is shown in FIG. Figure 5A The related ones are described in a similar manner and will not be repeated here to avoid confusion. Figure 5A and Figure 5B The relevant differences between them are unclear.

[0050] Figure 6 An example signaling flow 72 of an example STA-controlled uplink (UL) data transmission using an embodiment of a two-stage rate adaptation method is shown. The signaling flow 72 is similar to the example signaling flow 72 except that the directions of the arrows are all reversed. Figure 4 The signaling flow 36 is similar. For example, referring back to Figure 4 , the AP transmits uplink data to the STA in the pre-data transmission (e.g., 40a) phase and the data transmission (e.g., 44a) phase. Figure 6 In the signaling flow 72, the STA transmits uplink data transmission to the AP in the pre-data transmission (e.g., 76a (PRE-DATA TX)) phase and the data transmission (e.g., 80a (DATA TX)) phase. More specifically, the signaling flow 72 includes the STA sending an announcement 74 (announcement (ANNOUNCE) UL) of high-quality uplink data transmission service to the AP. The announcement 74 (e.g., a control message) initiated by the STA notifies the AP that there will be 3 rounds of data transmission and other configuration information, such as (for each round of transmission) the duration of the pre-data transmission, the expected start time of the data transmission phase, etc. In addition, the STA is Figure 6 The decision maker (regarding configuration) in the signaling flow 72 is shown. Figure 5A 46A, where the announcement 48 is also initiated by the STA, but the decision maker for the configuration is the AP (or Figure 5B In the illustrated signaling flow 46B, the decision maker for the configuration is the controller).

[0051] It is worth noting that the STA should know the information of the data transmission mode. In this example, the STA is the generator of the data packet, and thus the STA has knowledge of it. For example, the STA may be a WLAN device that communicates with a laptop or a robot, and the laptop or robot provides important data, for example, every 100 milliseconds. Therefore, the WLAN device (STA) understands the data traffic pattern. The STA may also or alternatively obtain the data traffic pattern from pre-configured information based on the application type in the packet header, based on the address of the destination node, based on the QoS type indicated in the packet header, and / or from a configuration message sent by an application server.

[0052] The first round of transmission includes the STA sending a set of test data packets during the pre-data transmission phase (phase 1) 76a (PRE-DATA TX). Data transmission is expected to occur at the STA at a set of predetermined time points (possibly with some minor delay variations), such as periodic data traffic with a given period between two packets. When a data packet Pi is expected to be generated at the STA at time ti, the STA starts the pre-data transmission procedure before ti. The start time can be configured as (ti – T_pre), where T_pre is a configurable parameter of the protocol operation. The STA can start the channel access contention at (ti – T_pre). If the channel contention is successful, the STA can become the TXOP holder.

[0053] The STA can transmit one or more pre-data transmission packets 76a, and the pre-data transmission packets can be data packets with a small dummy data payload, data packets with an empty data payload, null packets (e.g., null data PPDU), or control packets that request channel state measurement (e.g., probe PPDU).

[0054] Upon receiving the pre-data transmission, the AP can respond using the transmission result 78a (TX RSLT, which can include an ACK message and / or perform channel measurement, or the absence of an ACK message and / or channel measurement), and report the channel state information to the STA. The AP can respond using an ACK with piggybacked channel state information feedback.

[0055] The STA performs rate adaptation based on 76a and 78a. For example, when receiving an ACK message and / or channel state information feedback from the AP, the STA can perform link (e.g., rate) adaptation and select / re-select an appropriate transmission configuration (e.g., MCS, etc.).

[0056] Then, the STA transmits application data packets (DATA TX) to the AP 80a. The STA can transmit multiple pre-data transmission packets until the number of transmitted pre-data transmission packets is equal to the upper limit packet number N_max, the time for pre-data transmission is greater than or equal to the time threshold T_max, the application data predicted to arrive at time ti has arrived at the STA WLAN radio interface, or the STA can (prematurely) terminate the pre-data transmission phase and start data transmission (e.g., preempt).

[0057] The above two-phase rate adaptation method described for the signaling flow 72 is repeated for the second round of transmission (76b, 78b, and 80b) and the third round of transmission (76c, 78c, and 80c). Compared with Figure 4 the signaling flow 36 shown, Figure 4 the signaling flow 36 shown and Figure 6The only difference between the illustrated signaling flows 72 is which entity initiates or controls the two-stage rate adaptation transmission.

[0058] Figure 7 An example signaling flow 82 is shown of a pre-data transmission phase (Phase 1) followed by a data packet transmission phase (Phase 2) using a plurality of different MCSs. Recall that Figure 4 , Figure 5A , Figure 5B and Figure 6 It is shown that in the pre-transmission phase, empty (e.g., artificial or non-important) packets are sent to the receiving device and an effort or multiple efforts are made to determine improvements to the MCS, rate, etc. In other words, for each round, the MCS is adjusted based on the success of the transmission (e.g., if the previous data was received well, it can be transmitted through a higher rate layer). In this way, rate adaptation is performed earlier than in the prior art methods that initiate rate adaptation during the data transmission phase. Figure 7 In the illustrated embodiment, before the data transmission phase, there are multiple continuous pre-data transmission sequences, each of which uses a different MCS. The MCS of each sequence may be different in terms of aggressiveness, such as rate, but the rate adaptation strategy is artificial and does not consider the channel conditions. For example, if there is no ACK for one or more of the sequences, the MCS used during the data transmission phase may be more robust (for example, due to the poor channel quality, where a slower rate and more robust transmission can be used to improve the fidelity of the transmission). On the contrary, if ACK is received for each sequence, the data transmission phase can use a transmission at a faster data rate. However, in each example just described above, the MCS used during the pre-data transmission phase does not have to consider channel conditions, but is pre-selected. The MCS selected for, for example, MCS1 may be considered too aggressive (or too robust) for the current channel conditions, but it is attempted anyway. In this regard, the ordering of MCS sequences may be selected somewhat randomly based on differences in robustness, rate, etc., or in some embodiments, may be pre-selected based on known characteristics or historical performance (e.g., in a previous set of MCS sequences, better performance was achieved using a particular ordering of MCS sequences) and / or based on the type of wireless device. For example, the applied MCS sequence may be configured using a control message, determined based on previous rate adaptation results, determined from the most robust MCS to the least robust MCS (higher transmission rate), determined from a higher rate MCS to a lower rate MCS, or determined from the most likely MCS configuration.

[0059] In by Figure 7In the example shown in the illustrated signaling flow 82, there is a first sequence in which the STA sends a pre-data transmission using a first MCS (MCS1) 84a (PRE-DATATX(MCS1)), which results in a transmission result 86a (e.g., TXRSLT, which includes ACK and / or channel feedback or channel state information (CSI) or no response). In the next (continuous) sequence, the STA sends a pre-data transmission using a second MCS (MCS2) 84b (PRE-DATA TX(MCS2)), which results in a transmission result 86b (e.g., TX RSLT, ACK and / or channel feedback or no response). For the third (continuous) sequence, the STA sends a pre-data transmission using a third MCS (MCS3) 84c (PRE-DATA TX(MCS3)), which results in a transmission result 86c (e.g., TX RSLT, which may include the presence or absence of ACK and / or channel feedback). In this example, there is a preset (in terms of type and order) of three (3) pre-data transmissions using a consecutive sequence of MCS1, MCS2 and MCS3, which is actually a series of tests (e.g., test 1 uses MCS1, test 2 uses MCS2, and test 3 uses MCS3, which together constitute the pre-data transmission test sequence). Based on the transmission results 86a, 86b and 86c, the preferred (e.g., optimal) MCS transmission is selected for the data transmission stage 88. It should be noted that Figure 7 The continuous sequence including MCS1, MCS2, and then MCS3 shown in is an exemplary sequence for illustration, and in some embodiments, different sequence orderings or different numbers of sequences may also be used (e.g., MCS3, MCS2, then MCS1, or MCS1, MCS3, then MCS2, etc.). Feedback from the common MCS sequence (e.g., transmission results, whether channel measurements are performed, or other feedback as described above) enables determination of a suitable (e.g., optimal) MCS for the data transmission phase. It is worth noting that the rate adaptation module used in the STA needs to be aware of this testing strategy because if there are poor transmission results for any given sequence (e.g., no ACK is received, or the channel quality indicates that the MCS is a poor choice for the channel conditions), the rate adaptation module makes decisions based on the selection of a specific MCS rather than the channel conditions.

[0060] Figure 8An exemplary communication system 90 is shown in which various devices (e.g., WLAN devices and WLAN APs) can implement an embodiment of a two-stage rate adaptation method. It should be noted that the communication system 90 is an illustration of an exemplary system and various variations in arrangement and components can be implemented. The communication system 90 includes one or more controllers 92 (one is shown) connected (wired, such as via Ethernet) to a plurality of APs 94. The controller 92 may have a computer architecture including one or more processors, memory, and a communication interface coupled to one or more buses. The APs 94 in turn wirelessly communicate with one or more devices 96, which may include devices such as those described above. Figures 4 to 7 STAs are described in association with the signaling flows shown in . The communication system 90 may be implemented in an office or area according to a hybrid wired / wireless WLAN communication system, or in a smart environment as described above. In some examples, as reflected by the types of devices 96 shown in the communication system 90, the communication system 90 may be implemented in an office, a factory, a hospital, a research facility, a home, or even a vehicle.

[0061] The controller 92 may be a stand-alone server or computer, or generally a computing device, or a network of controllers co-located in a single facility or having functionality distributed among different locations (e.g., a server farm, a cloud computing environment). The AP 94 may also include one or more components, and may include a WLAN AP (e.g., an IEEE 802.11 AP), a router, or a device that provides, for example, hotspot functionality (e.g., a phone, a laptop, etc.). Each of the APs 94 may communicate wirelessly with one or more devices 96 (e.g., WLAN devices). The devices 96 may include laptops, notebook computers, tablet computers, smartphones, and / or entertainment devices (e.g., game controllers) with 802.11 wireless communication capabilities (e.g., equipped with an 802.11 WLAN radio interface), as well as other example devices. In Figure 8In the exemplary arrangement shown, an AP 94, represented as an 802.11AP, is shown to be wirelessly communicating with multiple devices 96 or stations (STAs) including a laptop computer (802.11STA1-1), a smartphone (802.11STA1-2), and a game controller (802.11STA1-3). An AP 94, represented as an 802.11AP, is wirelessly communicating with a single device 96 (e.g., STA), namely a laptop computer (802.11STA2-1). An AP 94, represented as an 802.11APn (n indicates an integer, which is 3 or greater than 3 in this example), is shown to be wirelessly communicating with two devices 96 (a smartphone 802.11STA3-1 and a game controller 802.11STA3-2). Again, the arrangement and selection of components are merely illustrative of an exemplary communication system 90, and different numbers or types of components may be used as an environment in which certain embodiments of the two-stage rate adaptation method may be implemented.

[0062] Fig. 9 Shown in Fig. 9An example computing architecture of a device 98 with wireless capabilities used in the communication system 90 is shown. The device 98 with wireless capabilities may be a computing architecture for either the AP 94 or the device 96. The device 98 with wireless capabilities may include a (non-transitory) memory 100 (MEM), a processor 102 (e.g., PROC, such as a microprocessor or an application specific integrated circuit (ASIC)), and a communication interface 104 (e.g., CMNC INT, such as an 802.11 WLAN radio interface). In some embodiments, there may be multiple processors or one or more multi-core processors. The memory 100 may be any data storage device that can store program code 106 (PRGMCODE) accessed and executed by the processor 102. Examples of the memory 100 include, but are not limited to, a read-only memory, a flash memory, a random access memory, a hard disk, an optical data storage device, a non-volatile storage unit, a non-transitory computer-readable medium (e.g., a tangible medium), etc. In one embodiment, the memory 100 is implemented as a non-transitory computer-readable medium. The communication interface 104 may include a transceiver 110 (TRNCVR) for transmitting and receiving signals (e.g., data, messages and / or packets) based on the processing results of the processor 102. In one embodiment, the device 98 with wireless capabilities includes rate adaptation logic or rate adaptation module 108 (RA MOD), which may be software composed of program code 106 (e.g., device driver), or hardware or a combination of hardware and firmware residing in the processor 102 (including a separate chipset), or a combination of both. The rate adaptation module 108 includes the functions of the two-stage rate adaptation method described herein. Generally speaking, the rate adaptation module 108 implements functions related to implementing a pre-data transmission stage (stage 1) and a data transmission stage (stage 2), including the configuration of rate adaptation (e.g., MCS selection or pre-selection (e.g., the latter such as Figure 8 ), rate, etc.) and parameter selection (e.g., parameters for pre-data transmission, parameters for data transmission and number and size of packets, arrival time prediction, etc., as described herein). In some embodiments, at least a portion of the functionality of rate adaptation module 108 (e.g., for MCS selection) may be implemented in one or more tables with different configurations of settings to select from.

[0063] Certain embodiments of a two-stage rate adaptation method have been described, along with an exemplary wireless communication system 90 and a wireless-capable device 98 (see, e.g., Figures 1 to 9 ), it should be understood that an embodiment of the exemplary two-stage rate adaptation method or more generally as follows Fig.10The method of configuring rate adaptation for data transmission 112 as shown includes the following. For a first phase 114 (PHS1), the method includes sending a set of test data packets (116) and determining a first rate adaptation configuration (118) based on feedback corresponding to the sending of the set of test data packets. For a second phase (120) (PHS2), the method includes sending a set of application data packets (122) according to the first rate adaptation configuration and determining a second rate adaptation configuration (124) based on at least one of the sending of the set of test data packets or the set of application data packets.

[0064] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be regarded as illustrative or exemplary rather than restrictive. Therefore, it should be understood that where reference marks are attached to features mentioned in the appended claims, such marks are included only for the purpose of improving the intelligibility of the claims and are in no way limiting the scope of the claims or the specification. The present invention is not limited to the disclosed embodiments. By studying the drawings, the disclosure and the appended claims, a person skilled in the art can understand and implement other variations of the disclosed embodiments when practicing the claimed invention. It should be noted that various combinations of the disclosed embodiments may be used, and therefore reference to an embodiment or an embodiment does not mean that features from this embodiment are excluded from being used together with features from other embodiments. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

Claims

1. A method for configuring rate adaptation for data transmission, the method comprising: For the first stage: Send a set of test packets; as well as determining a first rate adaptation configuration based on feedback corresponding to said sending of said set of test packets; For the second stage: sending a group of application data packets according to the first rate adaptation configuration; as well as A second rate adaptation configuration is determined based on at least one of the sending of the set of test packets or the sending of the set of application packets.

2. The method of claim 1, further comprising determining the first rate adaptation configuration or the second rate adaptation configuration based on an expected packet traffic pattern or a predictable packet traffic pattern.

3. The method of claim 2, wherein the expected data packet traffic pattern or the predictable data packet traffic pattern comprises a periodic data traffic pattern.

4. The method of claim 2, further comprising receiving information about the predictable packet traffic pattern based on receiving one or any combination of: Application type in the packet header; one or a combination of an address of a source node and an address of a destination node; the quality of service type in the packet header; Configuration messages sent by the application server; and Configuration message sent by the wireless LAN controller.

5. The method of claim 2, further comprising receiving information about the predictable packet traffic pattern based on one or any combination of the following: Set strategy; receiving a configuration message sent by a wireless LAN controller; and A control message is received from another device, the control message comprising one or any of the following: A set of time points at which the transmission is expected; The expected size of each packet; The period of a periodic traffic flow; The start time of the uplink data flow; The end time of the downlink data flow; and The number of packets of the periodic data flow.

6. The method according to claim 1 also includes sending the set of test data packets according to a scheduled start time and a period, wherein the scheduled start time is related to an expected start time for sending the set of application data packets, and the expected start time for sending the set of application data packets starts at the end of the period.

7. The method of claim 6, wherein the scheduled start time and the period for sending the set of test data packets are configurable parameters.

8. The method of claim 6, further comprising initiating channel access contention during the period.

9. The method of claim 1 , further comprising delaying the sending of the set of test data packets based on a scheduled start time and a period, the scheduled start time being related to an expected start time for sending the set of application data packets, wherein the delay is based on a time period corresponding to a busy channel that partially encroaches on the period, and the expected start time for sending the set of application data packets is initiated at the end of the period.

10. The method of claim 9, wherein the scheduled start time and the period for sending the set of test data packets are configurable parameters.

11. The method of claim 9, further comprising initiating channel access contention during the period.

12. The method of claim 1, wherein the set of test packets comprises one of: Data packets with dummy data payloads or empty payloads; an empty value bag; or Control package.

13. The method of claim 1, wherein the feedback comprises one or a combination of the following: a confirmation message from another device; and The channel state information is from the other device.

14. The method of claim 1, further comprising determining the first rate adaptation configuration and the second rate adaptation configuration by selecting one or a combination of a modulation and coding scheme, a transmission rate, and a multiple-input multiple-output configuration.

15. The method according to claim 1 also includes sending multiple transmission rounds of both multiple groups of test data packets and corresponding multiple groups of application data packets until one of an upper limit on the number of packets sent, a time threshold has passed, or sending the multiple transmission rounds based on receiving data corresponding to the multiple groups of application data packets.

16. The method of claim 1, further comprising terminating the first phase early before an expected start time based on receiving data corresponding to the set of application packets.

17. The method according to claim 1 also includes sending multiple transmission rounds of corresponding multiple groups of test data packets, wherein the multiple transmission rounds include different modulation coding schemes sorted according to one of previous rate adaptation results, the sorting is from more robust to least robust, from higher rate to lower rate, or from the most likely configuration, and also includes determining the first rate adaptation configuration based on feedback corresponding to the sending of the multiple groups of test data packets corresponding to the multiple transmission rounds.

18. The method according to claim 1, further comprising determining the group of test data packets according to one or any combination of the number of test data packets in each group, the time interval between multiple test data packets, and the size of each of the multiple test data packets.

19. The method of claim 1, wherein the first stage and the second stage are implemented in one of an access point or a station, and the method further comprises configuring, based on the implementation details from another device, implementation details of the first rate adaptation and implementation details of the second rate adaptation according to the first stage and the second stage, with or without a corresponding request for the rate adaptation.

20. A device having wireless capabilities, comprising: Transceiver; memory, including program code; as well as a processor, coupled to the transceiver and the memory, and configured to execute the program code to: For the first stage: Send a set of test packets; as well as determining a first rate adaptation configuration based on feedback corresponding to said sending of said set of test packets; For the second stage: sending at least one group of application data packets according to the first rate adaptation configuration; as well as A second rate adaptation configuration is determined based on at least one of the sending of the set of test packets or the sending of the set of application packets.

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