IMPROVEMENT MECHANISM FOR FINE TIME MEASUREMENT

Abstract

Implementations of this disclosure provide an approach for a fine-time measurement improvement mechanism. One method involves the acquisition of a set of parameters for each of a plurality of links between the access point (AP) multi-link device (MLD) and a set of station MLDs by an AP MLD. The AP MLD can then use the set of parameters to determine a score for each of the plurality of links. The plurality of scores for the plurality of links can be used to select a set of links from the plurality of links to transmit a plurality of FTM frames. The AP MLD further determines a number of FTM frames to be transmitted on one of the link groups. The AP MLD then transmits the number of FTM frames to the set of station MLDs over the selected link from the set of links.

Description

background Final Time Measurement (FTM) is also known as Wi-Fi Round Trip Time (RTT). The purpose of FTM is to estimate the distance between a starting station and a responding station. For example, the time difference between the initiating and responding stations is calculated to determine the distance. Compared to a location function based on the received signal strength indicator (RSSI), FTM is an upgrade or improvement technology. Multi-Link Operation (MLO) is a key feature of Media Access Control (MAC) introduced in Wi-Fi 7. It allows devices to exchange frames across multiple links. MLO enables a station's Multi-Link Device (MLD) to discover, authenticate, associate, and establish multiple connections with an Access Point (AP) MLD. Each connection allows channel access and frame exchange between the station MLD and the AP MLD based on the supported capability exchanged during association. Brief description of the drawings Implementations of the present disclosure can be understood from the following detailed description when read together with the accompanying figures. In accordance with common industry practice, various features are not drawn to scale. Indeed, the dimensions of the various features may be arbitrarily enlarged or reduced for the clarity of the discussion. Some examples of the present disclosure are described with reference to the following figures. Fig. 1 shows a block diagram of an example environment in which reference implementations of the present disclosure may be implemented; Fig. 2 shows an example of the use of a connection for transmitting FTM frames according to the implementations of the present disclosure; Fig.Figure 3 shows an example of using multiple links to transmit FTM frames according to the implementations of this disclosure; Figure 4 shows an example of transmitting FTM frames over two links according to the implementations of this disclosure; Figure 5 shows an example of transmitting FTM frames in a restricted Wake Time (R-TWT) Service Period (SP) according to the implementations of this disclosure; Figure 6 shows a flowchart for determining an overall measurement error and a target total number of FTM frames according to the implementations of this disclosure; Figure 7 shows a flowchart of an example procedure for controlling an AP MLD according to implementations of this disclosure; and Figure 8 shows an example of an Access Point Multi-Link device according to the implementations of this disclosure. Detailed description As described above, the FTM is used to estimate the distance between an initiating station and a responding station. Because the FTM measurement process is time-dependent, the unicast frame for the FTM must be transmitted multiple times between the initiating and responding stations within a short inter-frame space (SIFS) period, which can be referred to as an FTM burst. If the initiating station has multiple neighbors, it must communicate with each neighbor individually. In this case, a problem arises because the current working / home channel band is occupied during the FTM process, resulting in an interruption of the station's own traffic and increasing the time delay. To achieve accurate FTM results, several factors are required, such as a large bandwidth, the latest high efficiency (HE) / extended high throughput (EHT) standard, and lower interference, etc. Another problem is that while multiple FTM bursts contribute to improved accuracy, they can also cause BSS services to be interrupted regularly. Furthermore, Multi-Link Operation (MLO) is a key feature of Media Access Control (MAC) introduced in WiFi 7, and MLO allows a non-AP MLD to establish multiple connections with an AP MLD. Each of these connections enables channel access and frame exchange between the non-AP MLD and the AP MLD. However, there is no readily available guidance or widely adopted technology for utilizing the MLO feature with the FTM. Moreover, the two aforementioned issues become even more complex in MLD scenarios. Therefore, implementations of this disclosure propose a solution to improve FTM for Wi-Fi 7 MLDs. According to the implementations of this disclosure, the AP MLD can detect a set of parameters for each of a plurality of links between the AP MLD and a set of station MLDs. The AP MLD can then use this set of parameters to determine a score for each of the plurality of links. The plurality of scores for the plurality of links is used to select a set of links from the plurality of links to transmit a plurality of FTM frames. Next, the AP MLD can determine a number of FTM frames to transmit on one of the link groups. The AP MLD then transmits the number of FTM frames to the group of station MLDs over one of the links. Therefore, the AP MLD can use the scores for the multitude of connections to identify a group of connections from the multitude and distribute the multitude of FTM frames among that identified group. Thus, one connection is used to transmit the FTM frame, while other connections from the multitude can be used to transmit traffic between the AP MLD and the set of station MLDs. This method avoids the time delay and interruption of traffic between the AP and the set of station MLDs during the execution of an FTM measurement procedure. Further advantages of implementations of the present disclosure are described with reference to the reference implementations described below. Figures 1 to 2 illustrate the basic principles and several reference implementations of the present disclosure. Fig. 1 shows a block diagram of an example environment in which reference implementations of the present disclosure can be implemented. In the example environment 100 of Fig. 1, an AP MLD 104 communicates with a set of station MLDs 102 via a plurality of connections, e.g., a connection 106-1, ..., a connection 106-N, where N is an integer. In one example, the majority of connections may consist of two connections. For instance, one connection may be at 2.4 GHz and the other at 5 GHz. In another example, the plurality of connections may consist of three connections. For instance, a first connection may be at 2.4 GHz, a second at 5 GHz, and a third at 6 GHz. The above examples are for illustrative purposes only and do not constitute a limitation of the revelation. The set of station MLDs 102 comprises station MLD 102-1, station MLD 102-2, ..., and station MLD 102-M, where M is an integer. Each of the stations MLD 102-1, MLD 102-2, ..., and MLD 102-M can communicate with the AP MLD 104 via some or all of the available links. For example, there are three links between the AP MLD 104 and the set of stations MLD 102. The 2.4 GHz, 5 GHz, and 6 GHz bands are used. Station MLD 102-1 can communicate with the AP MLD 104 via two links, for example, the 2.4 GHz and 5 GHz links. Station MLD 102-2 can communicate with the AP MLD 104 via three links. In implementations of the present disclosure, the AP MLD 104 can detect a set of parameters for each connection of the plurality of connections. For example, the AP MLD 104 can detect a set of connection parameters 108-1 for connection 106-1; and for connection 106-N, the AP MLD 104 can detect a set of connection parameters 108-N. Furthermore, the detected parameters are the same for each connection. For example, the AP MLD 104 can detect the number of stations connected to it on each of its multiple links. Furthermore, the AP MLD 104 can detect the channel utilization for each of its multiple links, which refers to the proportion of time a communication channel is actually in use within a given period. Additionally, the AP MLD 104 can detect traffic priority, station types, bandwidth, noise floor, received signal strength indicator (RSSI), and / or results from a previous FTM. Therefore, the parameter set for each link can include at least one of the following parameters: the number of stations, channel utilization, traffic priority, station types, bandwidth, noise floor, RSSI, and results from a previous FTM to calculate a link score.The above description serves only to illustrate the revelation and does not constitute a limitation of the revelation. The parameter set may contain any suitable parameters. After receiving the parameter set for each of a multitude of links, the AP MLD 104 can use the parameter set to calculate a link score to evaluate link quality. For example, the parameter set 108-1 for link 106-1 can be used to calculate a score of 110-1 for link 106-1; the parameter set 108-N for link 106-N can be used to calculate a score of 110-N for link 106-N. In one example, the AP MLD 104 uses the number of stations, channel utilization, bandwidth, noise floor, RSSI, and result feedback from a previous FTM on link 106-1 to calculate a link score for link 106-1. The AP can then determine a set of connections from the multitude of connections based on the scores assigned to those connections. For example, AP MLD 104 can select a connection from the multitude based on its scores. The selected connection is used to transmit a multitude of FTM frames between AP MLD 104 and the set of stations MLD 102. In another example, AP MLD 104 can select the multiple connections with scores greater than a threshold. The selected multiple connections are used to transmit a multitude of FTM frames between AP MLD 104 and the set of stations MLD 102. Additionally or alternatively, the multitude of connections that have scores are selected or determined to transmit a multitude of FTM frames between AP MLD 104 and the set of stations MLD 102. Furthermore, the AP MLD 104 must also determine the number of FTM frames 112 to be transmitted on a connection within the group of connections. For example, if connection 106-1 is selected to transmit the FTM frames, the AP MLD 104 further determines the number of FTM frames to be transmitted on connection 106-1. The AP MLD 104 can determine the number of FTM frames to be transmitted on a connection based on the connection's score. For example, if the scores for the multitude of connections are used to select only one connection for transmitting the FTM frames, the number of FTM frames transmitted on the selected single connection is the total number of FTM frames for the multitude. If all of the multiple connections are used to transmit the FTM frames, the scores are used to distribute the FTM frames across the multiple connections.For example, if the score for a connection is higher, more FTM frames will be allocated to the connection, and if the score for a connection is lower, fewer FTM frames will be allocated to the connection. The AP MLD 104 then uses the determined set of connections to transmit the multitude of FTM frames. By transmitting the FTM frames, the AP MLD 104 can perform FTM measurements. These FTM measurements can be used to estimate the distance between the AP MLD 104 and the destination station receiving the FTM frames. By performing multiple FTM measurements, the distance can be calculated precisely. Figure 2 shows an example 200 for the use of a link for transmitting FTM frames according to the implementations of the present disclosure. In the example 200, a set of station MLDs 202 communicates with the AP MLD 204 via a plurality of links, including a link 206-1, a link 206-2, ... and a link 206-N. For the plurality of links, the AP MLD 204 can obtain link parameters for each link of the plurality of links. The AP MLD 204 then uses the obtained link parameters to calculate a score for each link, thereby enabling the AP MLD 204 to obtain a plurality of scores for the plurality of links. In some implementations, the AP MLD 204 can use an algorithm to calculate a score for each of the multiple connections. This algorithm uses a number of stations, station types (MLD or non-MLD), a number of supported bands, traffic priority, and channel utilization to calculate a score for a connection. Therefore, according to the algorithm, multiple scores are determined for the multiple connections. Then, a target score 208 is selected from the multiple scores. The target score is, for example, the highest score. Therefore, the connection with the highest score is selected from the multiple connections to transmit all FTM frames 210 between the AP MLD 204 and the set of station MLDs 202 in order to perform an FTM measurement, for example, to perform FTM scans for specific FTM-enabled neighboring devices. Alternatively, a configuration button can be introduced as “MLD FTM auto”. When this button is activated and FTM scanning is enabled on multiple radios, the AP MLD 204 selects the best connection from the multitude of connections for the FTM scan to avoid interfering with station traffic on other links between the AP MLD 204 and the set of station MLDs 202 at the same time. In some implementations, the AP MLD 204 can use the following equation (1) to calculate a score for each link of the plurality of links: where Δweight represents a score or standard for a link, f() is a function used to calculate a score, NF is a noise floor, RSSI is an indicator of received signal strength, and feedbacklink-ie is a linkiFTM result feedback. Therefore, the AP MLD 204 can obtain a plurality of scores for the plurality of links. In one example, the AP MLD 204 determines a highest score from the plurality of scores as a target score 208 and selects the link with the highest score from the plurality of links. The selected link is then used to transmit all FTM frames 210 between the AP MLD 204 and the set of station MLDs.In another example, the AP MLD 204 can determine the lowest score from a multitude of scores as the target score and select the connection with the lowest score from among those connections. Therefore, the connection with the lowest score is used for transmitting all FTM frames 210. As described above, the destination link or selected link is used to transmit all FTM frames 210 between the AP MLD 204 and the set of station MLDs. Since only one link is used for transmitting the FTM frames, the other links in the multitude of links would not be used for this purpose. In this case, the other links are still used for traffic between the AP MLD 204 and the set of station MLDs 202. Therefore, if a radio is performing an FTM scan, the AP MLD 204 prevents other radios from performing an FTM scan, thus allowing the station MLDs to maintain data traffic with minimal disruption. As described above, Fig. 2 shows an example of FTM frame transmission using a connection. Another example of FTM frame transmission is presented with reference to Fig. 3. Fig. 3 shows examples of using a plurality of connections to transmit FTM frames according to the implementations of the present disclosure. In Example 300, the AP MLD 304 and a set of station MLDs 302 communicate with each other over a multitude of links, including links 306-1, 306-2, ..., 306-N. The AP MLD 304 can calculate a multitude of scores for the multitude of links, and each link has a corresponding score. The score can be calculated with reference to the content described in Fig. 2. For example, the AP MLD 304 can determine a score 308-1 for link 306-1, a score 308-2 for link 306-2, ..., and a score 308-N for link 306-N. The AP MLD 304 can then use the multitude of scores to determine how many FTM frames need to be transmitted over each of the multitude of links. For example, the AP MLD 304 determines the FTM frames 310-1 that are transmitted on link 306-1, based on the score 308-1.The AP MLD 304 determines the FTM frames 310-2 that are transmitted on link 306-2, based on the score 308-2, and determines the FTM frames 310-N that are transmitted on link 306-N, based on the score 308-N. Furthermore, the AP MLD 304 can determine the total number of FTM frames in a multitude between the AP MLD 304 and the set of station MLDs 302. The total number of FTM frames in the multitude corresponds to the total number of bursts. The total number of bursts is calculated using the following equation (2): where Nclients is the total number of stations and Meach client burst number is the number of FTM exchange times each station must perform. After determining the total number of a multitude of FTM frames, the AP MLD 304 can further distribute the multitude of FTM frames across the multitude of links according to the multitude of ratings. The total number of bursts can also be calculated, for example, using the following equation (3): where Δweight-ie represents a rating for linki, n represents the number of multiple connections, and linki represents the i-th connection. The value of linki in the above equation (3) can be 1. Therefore, the number of FTM frames for one unit of Burstmin score can be calculated using the following equation (4): After the burst min has been determined, the FTM frame to be transferred to the linki can be calculated by multiplying burst min with Δweight-iber. In some implementations, the AP MLD 304 can calculate a ratio across a multitude of ratings. The AP MLD 304 then uses these ratio elements as the corresponding scores. Therefore, each of the multiple links has a corresponding ratio element. Based on the total number and the ratio, the AP MLD 304 can then determine the number of FTM frames to be transmitted on each group of links. For example, if the station has 8 MLDs and the burst size is 8, then Ntotal burst = 64. Assuming there are three MLD links, and after calculation, the ratio of Δweight for the three links is 4:3:1, then Burstmin is 8. The final FTM burst number assigned to each link is then Link-1: 32, Link-2: 24, Link-3: 8. As described above, the majority of TWT frames can be distributed across the majority of links. In this case, the multitude of links can be used to transmit the multitude of FTM frames. The TWT feature (individual / wide / restricted TWT) can be used to protect the FTM process so that each MLD link can transmit FTM bursts more accurately and efficiently. Figure 4 shows Example 400 for transmitting FTM frames across two links according to the implementations of this disclosure. In Example 400, R-TWT is used as an example. An AP MLD 402 has two virtual access points (VAPs), VAP 1 and VAP 2, and a station MLD 404 has two stations, STA 1 and STA 2. There are two links (Link 1 and Link 2) between the AP MLD 402 and the station MLD 404. Link 1 is used for communication between VAP 1 and STA 1, and Link 2 is used for communication between VAP 2 and STA 2. AP MLD 402 and station MLD 404 will establish an R-TWT session between Link 1 and Link 2. For example, there are two service periods (SPs) for R-TWT-1 on Link 1, SP 406 and SP 408. SP 406 and SP 408 are used for transmitting FTW frames assigned to Link 1. On Link 2, there are two SPs for R-TWT-2, SP 410 and SP 412. SP 410 and SP 412 are used for transmitting FTW frames assigned to Link 2. As shown in Fig. 4, this session was staggered. For example, SP 406 is used on connection 1 during different time periods than SP 410 and 412 on connection 2. Similarly, SP 408 on connection 1 is used during different time periods than SP 410 and 412 on connection 2.At the same time, SP 410 and SP 412 on connection 2 also differ in timing from SP 406 and SP 408 on connection 1. This method ensures that an MLD connection can serve clients when an FTM frame exchange is taking place on the other connection. Figure 5 shows some examples of the transmission of FTM frames in an R-TWT SP according to the implementations of this disclosure. In Example 500, the AP MLD sends a beacon 502 to STA 1 and STA 2 during an R-TWT scheduling process. The beacon contains at least two information elements (IEs): an R-TWT IE 504 and a quiet IE 506. The R-TWT IE 504 contains the start time of the R-TWT SP 510. The quiet message contains the start time of the quiet interval 508. The start time of the R-TWT SP 510 is the same as the start time of the quiet interval 508. Therefore, the quiet IE is used to counter the start time of the R-TWT SP; this signal can best guarantee the FTM exchange frame without other interference and make the result more accurate. Next, the AP MLD sends an RTS frame 512 (Request to Send) to the STA 1. The RTS frame contains information such as the time required for data transmission. After receiving the RTS frame 512, the STA 1 sends a CTS frame 514 (Clear to Send) to the AP MLD. Upon receiving the CTS frame 514, the AP MLD determines that it can begin sending data. The AP MLD then sends an FTM frame 516 to the STA 1 on link 1. The STA 1 accepts the FTM frame 516, generates an acknowledgment frame (ACK) 518 for the FTM frame 516, and sends the ACK frame 518 to the AP MLD. Next, the AP MLD can send another FTM frame 520 to the STA 1, and after the FTM frame 520 is received by the STA 1, the STA 1 continues to send an ACK frame 522 to the AP MLD. During this process, communication between the AM MLD and the STA 2 on the same link is prohibited. Fig.Figure 5 shows that in an R-TWT SP 1, two FTM frames are sent to the STA 1. This is an example to illustrate the disclosure and not a limitation of the disclosure. In some implementations, more FTM frames or a single FTM frame are transmitted in an R-TWT SP. Furthermore, the situation for the single / broadcast TWT is the same as for the R-TWT. After the FTM frames have been transmitted over the multitude of links, the FTM measurements across these links are aggregated to reduce the overall measurement error and thereby improve the overall accuracy. In this case, a small burst N (number of measurements) is determined while the total error E remains below a certain threshold. This process is described with reference to Fig. 6. Fig. 6 shows a flowchart for determining a total measurement error and a target total number of FTM frames according to the implementations of this disclosure. In procedure 600, the AP MLD 104 in block 602 determines a measurement error for a multitude of FTM frames on one of the set of links. When the AP MLD 104 sends an FTM frame to a station MLD, an FTM measurement result is received. The AP MLD 104 can further calculate the measurement error for a multitude of FTM frames by using the FTM measurement result. For example, there are multiple connections between the AP MLD 104 and the set of station MLDs 102 to transmit the FTM frames. The number of these multiple connections is n. The measurement error obtained on connection i (1 ≤ i ≤ n) is then denoted as ei for the FTM measurement times Ni. The error ei for the FTM measurement times Ni can be an average error ei,avg, which is the average value for the n measurements. For each measurement, the AP MLD can obtain an error value. These error values ​​for the FTM measurement times Ni can be used to calculate the measurement error sei. In some implementations, the error value for each measurement can be calculated by using a nearby access point with a static location. In other implementations, Bluetooth Low Energy (BLE) technology or a Global Positioning System (GPS) can be used to calculate the reference location. The error value for each measurement is then calculated by comparing the measured location to the reference location. In block 604, the AP MLD 104 determines an error weight corresponding to the measurement error. After the AP MLD 104 has determined the measurement error for the multitude of measurements on the link, an error weight corresponding to the measurement can be calculated. The error weight corresponding to the measurement error can be determined using several link parameters. These parameters can include, for example, at least one of the following: throughput priority, channel utilization, noise floor, physical layer (PHY) and media access control (MAC) layer capability, number of stations, and result feedback for a previous FTM measurement. For the measurement error ei on link i, the corresponding weight is, for example, wi, which can be calculated using the following equation (5), where TPpriority represents a throughput priority, chanutil represents channel utilization, NF represents background noise, PHY_MACcapability represents the physical layer and media access control layer capability, and clientnum represents the number of stations. Furthermore, the input parameters may also include feedback from a previous FTM measurement. In some implementations, the function used to calculate the corresponding weight may be the same function used to calculate the score above, for ease of calculation. In block 606, the AP MLD 104 determines an objective function based on the measurement error and error weighting. To achieve a small burst N and a suitable total error E, an objective function is used to meet the above requirement. The objective function can use the measurement error and error weighting as parameters. The objective function can, for example, be represented as a weighted sum of the squared errors for each connection. The objective function (6) is shown below: In this objective function, the error weighting and the measurement counter Ni for the connection I can be set so that the effects of the error on each connection on the total error E are minimized as much as possible. In Block 608, the AP MLD 104 determines a variety of constraints corresponding to the objective function. To achieve optimal results for the objective function, it is necessary to define certain constraints. These constraints ensure that the objective function delivers the best possible outcome. For example, the constraints (7), (8), (9) and (10) for the objective function (6) above are shown below. The above constraints ensure that the total error E does not exceed a specific threshold E and that the number of measurements N for the multitude of connections is limited to Threshold N to minimize resource consumption or maximize efficiency. Threshold N is the value, which can be the example value 64 (total number of FTM bursts; other thresholds can also be predefined), mentioned in the examples above. FTM measurements on a specific connection or on all connections should be completed within a specific time; that is, the maximum / each of the measurements must not exceed a certain value. In some implementations, if the AP / STA MLD PHY / MAC conditions are similar, then the value is the same on all links. Therefore, the total FTM measurement error can be represented as the average of the measurement errors on each link, and a single link / band FTM optimization method needs to be reused. For example, In block 610, the AP MLD 104 determines the total measurement error and the target total number of FTM frames based on the objective function and the variety of constraints. The AP MLD 104 can use the above objective function and the variety of constraints to calculate the best total measurement error and the best number of FTM frames by trying different measurement errors and the number of FTM frames. Figure 7 shows a flowchart of an example procedure for controlling an AP MLD according to implementations of the present disclosure, and procedure 700 is performed by an AP MLD. In 702, the AP MLD detects a set of parameters for each of a plurality of links between the AP MLD and a set of station MLDs. For example, the AP MLD can perform measurements on the plurality of links and obtain the parameters for each of the plurality of links. For example, the AP MLD can determine the channel utilization by transmitting some frames on a link. In addition, the AP MLD can also determine the number of stations connected to the AP MLD via each link. For example, the AP MLD records all stations connected to it in the information table in the AP MLD, including the links through which the stations are connected to the AP MLD. At 704, the AP MLD determines a variety of ratings for the multitude of connections based on the parameter set. For example, if the AP MLD receives a set of parameters for each of the multitude of connections, it can calculate a score for the connection by inputting the connection's parameter set into a function. Therefore, the AP MLD will generate a multitude of ratings for the multitude of connections. The score for a connection can be used to indicate the quality of the connection. At 706, the AP MLD, based on the multitude of ratings, determines a set of connections from the multitude of connections for the transmission of a multitude of fine time measurement (FTM) frames. For example, after the AP MLD receives the multitude of ratings, it selects a group of connections to be used for transmitting the FTM frame in order to perform FTM measurements. During this process, the AP MLD uses the scores of the multitude of connections to select the group of connections. In some implementations, the AP MLD selects a link from the multitude of links to transmit all FTM frames between the AP MLD and the set of station MLDs. The selected link can have the highest or lowest score, determined based on the requirement. In other implementations, the APMLD can select a set of links from the multitude. Each of the selected links has a score greater than a threshold. In this case, a subset of the multitude of links is used to transmit all FTM frames between the AP MLD and the set of station MLDs. In some implementations, the AP MLD can select from a multitude of links. If a link has a score, this indicates that the link is available. Therefore, the multitude of links with their scores can be used to transmit FTM frames between the AP MLD and the set of station MLDs. Thus, in this case, all of the multiple links are used to transmit FTM frames. At 708, the AP MLD determines the number of FTM frames to be transmitted over one of the connections based on multiple scores. Since the AP MLD receives a score for each of the multiple connections, the connection score can be used to determine the number of FTM frames transmitted over that connection. For example, if a connection is selected to transmit the FTM frames based on the multiple scores, the number of FTM frames to be transmitted over that connection is the total number of FTM frames. When the multitude of FTM frames is transmitted over the multitude of connections, the AP MLD can determine the number of FTM frames to be transmitted over a connection based on the connection score.For example, the AP MLD can determine a ratio of the multitude of ratings, then the AP MLD can determine a number of FTM frames to be transmitted over the connection based on the ratio element. At port 710, the AP MLD transmits the number of FTM frames over one of the links to the set of station MLDs. Once the number of FTM frames to be transmitted over a link has been determined, the AP MLD can send the number of FTM frames according to the request. For example, if the AP MLD sends the FTM frames on one link, the other links in the set would not send any FTM frames. The time frame for transmitting FTM frames on one link in the set differs from the time frame for transmitting FTM frames on another link in the set. In some implementations, the AP MLD can also determine the measurement results for the FTM frames transmitted on each link. The errors in the measurement results are then used to determine an optimal measurement time and a suitable overall error for all links. In this way, the AP MLD can use some links from the multitude of links for transmitting FTM frames, while other links are used for transmitting traffic frames. This avoids time delays and traffic interruptions between the AP and the group of MLDS stations. Fig. 8 shows an example of an AP MLD 800 according to the implementations of the present disclosure. As shown in Fig. 8, the AP MLD 800 comprises at least one processor 810, a memory 820 coupled to the processor 810, at least one antenna 840, at least one radio 850, an Ethernet interface 860, a management interface 870, and a power supply interface 880. The memory 820 stores instructions 822, 824, 826, 828, and 830 to cause the processor 810 to perform actions according to the reference implementations of the present disclosure. As shown in Fig. 8, memory 820 stores instructions 822 to identify a set of parameters for each of a plurality of links between the AP MLD and a set of station MLDs. Memory 820 further stores instructions 824 to determine a plurality of ratings for the plurality of links based on the set of parameters. In addition, memory 820 stores instructions 826 to determine, based on the plurality of ratings, a set of links from the plurality of links to transmit a plurality of fine time measurement (FTM) frames. Memory 820 further stores instructions 828 to determine, based on the multiple ratings, a number of FTM frames to be transmitted on one of the groups of links. As shown in Fig.As shown in Figure 8, memory 820 further stores instructions 830 to transmit the number of FTM frames over one of the links to the set of station MLDs. The stored commands and the functions that the commands can execute can be understood with reference to the implementations described above. For the sake of brevity, the details of commands 822, 824, 826, 828, and 830 are not discussed here. The single 840 antenna in the AP MLD 800 is a crucial component that enables the AP MLD 800 to communicate with wireless devices such as laptops, smartphones, and tablets. The primary function of the single 840 antenna is to transmit and receive wireless signals by converting electrical signals into radio waves for outgoing communication and vice versa for incoming signals. The at least one 850 radio unit in the AP MLD 800 is responsible for wireless communication. This unit can convert data between wired and wireless formats, enabling the AP MLD 800 to transmit and receive data wirelessly. Through modulation, the digital data from the wired network is converted into radio waves for wireless transmission. A demodulation process then converts the incoming radio waves back into digital data that the AP MLD 800 can process. The at least one 850 radio unit can operate in specific frequency bands, such as 2.4 GHz, 5 GHz, or 6 GHz. It ensures effective communication by selecting appropriate channels to minimize interference. The performance of the at least one 850 radio unit can be defined by various Wi-Fi standards, including 802.11a / b / g / n / ac / ax, with newer standards such as Wi-Fi 6 and Wi-Fi 7 offering improved speed, efficiency and capacity. The Ethernet interface 860 on the AP MLD 800 can be used to connect the AP MLD 800 to the local network and bridge the wired and wireless segments of the network. The AP MLD 800 can be connected to routers, switches, or directly to the internet via the Ethernet interface 860, allowing wireless devices to communicate with other network resources and the wider internet. The Ethernet interface supports various speeds, including Fast Ethernet (e.g., 100 Mbps), Gigabit Ethernet (e.g., 1 Gbps), and even Multi-Gigabit Ethernet. The 870 management interface on the AP MLD 800 allows network administrators to configure, monitor, and manage the AP MLD 800's settings and performance. The 870 management interface can be accessed through various methods, such as a web browser, a command-line interface (CLI), or network management protocols like the Simple Network Management Protocol (SNMP). Through the 870 management interface, administrators can configure and modify SSIDs, security protocols, VLANs, and other operational parameters to ensure the AP 800 functions effectively within the network environment. The 880 power supply interface in the AP MLD 800 provides the necessary electrical power to ensure smooth and effective operation. This can be achieved through direct power supply via a power adapter plugged into a wall outlet or via Power over Ethernet (PoE), where power is supplied through the same Ethernet cable used for data transmission. Program code or instructions for carrying out the procedures of this disclosure may be written in any combination of one or more programming languages. These program codes or instructions may be provided to a processor or controller of a general-purpose computer, a specialized computer, or any other programmable data processing device, such that when executed by the processor or controller, the program codes perform the functions / operations specified in the flowcharts and / or block diagrams. The program code or instructions may be executed entirely on one machine, partially on the machine, as a standalone software package, partially on the machine and partially on a remote computer, or entirely on the remote computer or server. Program code or instructions for carrying out the procedures of this disclosure may be written in any combination of one or more programming languages. These program codes or instructions may be fed to a processor or controller of a general-purpose computer, a specialized computer, or any other programmable data processing device, such that when executed by the processor or controller, the program codes perform the functions / operations specified in the flowcharts and / or block diagrams. The program code or instructions may be executed entirely on one machine, partially on the machine, as a standalone software package, partially on the machine and partially on a remote machine, or entirely on the remote machine or server. In the context of this disclosure, a machine-readable medium can be any tangible medium capable of containing or storing a program for use by or in conjunction with a command-execution system, device, or apparatus. The machine-readable medium can be a machine-readable signaling medium or a machine-readable storage medium. A machine-readable medium can be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination thereof.More specific examples of a machine-readable storage medium would be an electrical connection with one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. Even though the processes are presented in a specific order, this does not mean that these processes must be executed in the presented order or in sequential order, or that all presented processes must be executed to achieve the desired results. Multitasking and parallel processing can be advantageous under certain circumstances. Certain features described in connection with separate implementations can also be implemented in combination within a single implementation. Conversely, various features described in connection with a single implementation can also be implemented separately in multiple implementations or in any suitable subcombination. The preceding detailed description of this disclosure refers to the accompanying drawings, which form part of this disclosure and illustrate how examples of the disclosure can be carried out. These examples are described in sufficient detail to enable those skilled in the art to put the examples of this disclosure into practice, and it is understood that other examples may be used and that process, electrical, and / or structural modifications may be made without departing from the scope of this disclosure.

Claims

A procedure comprising the following: Acquiring a set of parameters for each of a plurality of links between the AP MLD and a set of station MLDs by an Access Point (AP) Multi-Link Device (MLD); Determining, by the AP MLD and based on the set of parameters, a plurality of ratings for the plurality of links; Determining, by the AP MLD and based on the plurality of ratings, a set of links from the plurality of links to transmit a plurality of fine time measurement (FTM) frames; Determining, by the AP MLD and based on the plurality of ratings, a number of FTM frames to be transmitted on one of the group of links; and transmitting the number of FTM frames by the AP MLD to the group of station MLDs over one of the groups of links. Method according to claim 1, wherein the parameter set includes at least one of the following parameters: number of stations, channel utilization, station types, traffic priority, bandwidth, background noise, received signal strength indicator (RSSI), result feedback for a previous FTM measurement. The method of claim 1, wherein determining a set of compounds from the plurality of compounds for transmitting a plurality of fine time measurement frames (FTM) comprises: determining a highest score from the plurality of scores for the plurality of compounds; and determining a compound from the plurality of compounds corresponding to the highest score as the group of compounds. The method of claim 1, wherein the set of connections comprises the plurality of connections, and determining a number of FTM frames to be transferred on one of the set of connections comprises: determining a total number of the plurality of FTM frames to be transferred between the AP MLD and the set of station MLDs; and determining the number of FTM frames to be transferred on each of the multiple connections based on the total number and the multiple scores. The method of claim 4, wherein determining a total number of the plurality of Fine-Time-Measurement (FTM) frames to be transmitted between the AP MLD and a set of station MLDs comprises: determining a first number of station MLDs; determining a second number of FTM exchange times for each station of the set of MLDs; and determining the total number of the plurality of FTM frames based on the first number and the second number. The method of claim 4, wherein determining the number of FTM frames to be transferred on each of the group of connections based on the total number and plurality of scores comprises: determining a ratio for the plurality of scores; and determining the number of FTM frames to be transferred on each of the group of connections based on the total number and the ratio. The method of claim 4, wherein the transmission of the number of FTM frames over one of the groups of connections comprises: determining a set of FTM frames from the number of FTM frames; and transmitting the set of FTM frames over one of the set of connections during a Target Wake Time (TWT) Service Period (SP), wherein the TWT SP is temporally offset from a TWT SP on another connection of the set of connections. The method of claim 7, wherein the transmission of the set of FTM frames over one of the connections during a Target Wake Time (TWT) Service Period (SP) comprises: transmitting the set of FTM frames to a first station MLD of the set of station MLDs over one of the connections during the TWT SP; and preventing data communication between the AP MLD and other station MLDs of the group of station MLDs over one of the connections during the TWT SP. The method of claim 8, wherein the TWT SP is one of the following: an individual TWT SP, a broadcast TWT SP or a restricted TWT SP. The method according to claim 1 further comprises: determining a measurement error for a plurality of FTM frames on one of the group of connections; and determining an error weighting corresponding to the measurement error; and determining an overall measurement error and a target total number of FTM frames on the set of connections based on the measurement error and the error weighting. The method of claim 10, wherein the determination of an error weight corresponding to the measurement error comprises: determining the error weighting corresponding to the measurement error based on at least one of the following factors: throughput priority, channel utilization, noise floor, capability of the physical layer (PHY) and the media access control layer (MAC), number of stations, result feedback for a previous FTM measurement. The method of claim 10, wherein determining an overall measurement error and a target total number of FTM frames on the set of connections based on the measurement error and error weighting comprises: determining an objective function based on the measurement error and error weighting; determining a plurality of constraints corresponding to the objective function; and determining the overall measurement error and the target total number of FTM frames based on the objective function and the plurality of constraints. Access Point (AP) Multi-Link Device (MLD), consisting of: at least one processor; a memory connected to the at least one processor, the memory storing instructions to cause the at least one processor to: recognize a set of parameters for each of a plurality of links between the AP MLD and a set of station MLDs; determine a plurality of scores for the plurality of links based on the parameter set; determine a set of links from the plurality of links for transmitting a plurality of fine time measurement (FTM) frames based on the plurality of scores; determine a number of FTM frames to transmit on one of the groups of links based on the plurality of scores; and transmit the number of FTM frames to the MLD stations via one of the links. AP MLD according to claim 13, wherein the parameter set includes at least one of the following parameters: number of clients, channel utilization, station types, traffic priority, bandwidth, noise floor, received signal strength indicator (RSSI), result feedback for a previous FTM. AP MLD according to claim 13, wherein the instructions for determining a set of connections from the plurality of connections for transmitting a plurality of fine time measurement (FTM) frames comprise instructions to cause at least one processor to: determine a highest score from the plurality of scores for the plurality of connections; and determine a connection from the plurality of connections that corresponds to the highest score as the group of connections. AP MLD according to claim 13, wherein the set of connections comprises the plurality of connections and the instructions for determining a number of FTM frames to be transmitted on one of the set of connections comprise instructions to cause at least one processor to: determine a total number of the plurality of FTM frames to be transmitted between the AP MLD and the set of station MLDs; and determine the number of FTM frames to be transmitted on each of the multiple connections, based on the total number and the multiple scores. AP MLD according to claim 16, wherein the instructions for determining a total number of the plurality of fine time measurement frames (FTM) to be transferred between the AP MLD and a set of station MLDs comprise instructions to cause at least one processor to: determine a first number of the set of station MLDs; determine a second number of FTM exchange times for each station of the set of MLDs; and determine the total number of the plurality of FTM frames based on the first number and the second number. AP MLD according to claim 16, wherein the instructions for determining the number of FTM frames to be transferred on each of the group of connections based on the total number and plurality of ratings comprise instructions to cause at least one processor to: determine a ratio for the plurality of ratings; and determine the number of FTM frames to be transferred on each of the group of connections based on the total number and the ratio. AP MLD according to claim 16, wherein the instructions for transmitting the number of FTM frames over one of the group of connections comprise instructions to cause at least one processor to: determine a set of FTM frames from the number of FTM frames; and transmit the set of FTM frames over one connection of the set of connections during a Target Wake Time (TWT) Service Period (SP), wherein the TWT SP is staggered in time with a TWT SP on another connection of the set of connections. Non-transitory computer-readable medium containing stored commands which, when executed by an Access Point (AP) Multi-Link Device (MLD), cause the AP MLD to: recognize a set of parameters for each of a plurality of links between the AP MLD and a set of station MLDs; determine a plurality of scores for the plurality of links based on the parameter set; determine a set of links from the plurality of links to transmit a plurality of fine time measurement (FTM) frames based on the plurality of scores; determine a number of FTM frames to transmit on one of the groups of links based on the plurality of scores; and transmit the number of FTM frames to the MLD stations over one of the links.

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