Low-overhead channel sounding based on partial-band channel estimation in wi-fi 7

Abstract

Optimal determination of wireless local area network (WLAN) sounding methods and systems can be provided. An access point (AP) selects a subchannel for a partial sounding. The AP then sounds the selected subchannel. A client station responds with channel state information (CSI). In response to the sounding, the AP can receive the CSI from the client station. Based on the CSI from the selected subchannel, the AP extrapolates the CSI to determine predicted CSI for a wider bandwidth channel.

Description

[0001] This application was filed on January 6, 2022 as a PCT international patent application and claims the benefit and priority of U.S. non-provisional patent application serial number 17 / 145,252, filed on January 8, 2021, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to wireless networks. Background Technology

[0003] In computer networking, a wireless access point (AP) is a networking hardware device that allows Wi-Fi-compatible client devices to connect to a wired network and other client devices. An AP typically connects to a router as a standalone device (directly or indirectly via a wired network), but it can also be an integral part of the router itself. Multiple APs can also work in coordination through direct wired or wireless connections, or through a central system typically called a Wireless Local Area Network (WLAN) controller.

[0004] For a WLAN to function, client devices must be identified and located. Access points (APs) in a WLAN can use a process called "sounding" to identify and locate client devices. Sounding involves the AP sending reference signals to the client devices and receiving Channel State Information (CSI) feedback from the client devices.

[0005] For newer WiFi standards, the overhead of probing is very high. Furthermore, as the duration of the probing process increases, channel measurements become useless because the channel changes significantly between the time the access point emits a signal and subsequent data transmission. Consequently, the measured channel conditions become outdated, rendering the probing process ineffective. Attached Figure Description

[0006] The accompanying drawings, which are included in and constitute a part of this disclosure, illustrate various examples of this disclosure. In the drawings: Figure 1 It is a block diagram of a wireless network environment based on various aspects of this disclosure; Figure 2 It is a signaling or path map used for signaling procedures in accordance with various aspects of this disclosure for detecting channels; Figure 3 It is a block diagram of an AP antenna array according to various aspects of this disclosure; Figure 4This is a flowchart of a method for determining the minimum bandwidth for channel sensing according to various aspects of this disclosure; Figure 5 This is a flowchart of a method for detecting a subchannel according to various aspects of this disclosure; Figure 6A It is a block diagram of a computing device according to various aspects of this disclosure; and Figure 6B It is a block diagram of a wireless device according to various aspects of this disclosure. Detailed Implementation

[0007] Overview This provides an optimal determination of the WLAN probe method and system. The AP selects a sub-channel for partial probe. The AP then probes the selected sub-channel. The client site responds with a CSI. In response to the probe, the AP can receive the CSI from the client site. Based on the CSI from the selected sub-channel, the AP extrapolates the CSI to determine the predicted CSI for a wider bandwidth channel.

[0008] The foregoing overview and the following examples are merely illustrative and should not be construed as limiting the scope of this disclosure as described and claimed. Furthermore, other features and / or variations may be provided in addition to those described. For example, examples of this disclosure may be provided for various combinations and sub-combinations of features described in the examples.

[0009] Example The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and the following description to refer to the same or similar elements. While one or more examples of this disclosure may be described, modifications, adaptations, and other implementations are possible. For example, elements illustrated in the drawings may be replaced, added, or modified, and the methods described herein may be modified by replacing, reordering, or adding stages to the disclosed methods. Therefore, the following detailed description does not limit this disclosure. Rather, the proper scope of this disclosure is defined by the appended claims.

[0010] To perform a probe procedure, the AP can send a Null Data Packet Announcement (NDPA) to one or more client devices (also known as stations, STAs) to notify the STAs that a reference signal is coming. The AP then transmits this reference signal in the form of a Null Data Packet (NDP) during a Short Inter-Frame Space (SIFS) following the NDPA. Thus, the AP broadcasts the NDP during the SIFS following the NDPA. The NDP can be used by the STAs to evaluate the channel. For each Spatial Stream (SS), the NDP may include a High Efficiency (HE) Long TrainField 3 (LTF3) packet with a duration of 7.2, 8, or 16 µs (HE-LTF3). Upon receiving the NDP, the STA responds either sequentially or in parallel due to an Orthogonal Frequency Division Multiple Access (OFDMA) uplink with a Beamforming Report (BFR).

[0011] This paper presents various aspects of a low-overhead probing mechanism that may include two procedures. The first stage may include a mechanism to find the minimum bandwidth that can be supported for probing based on metrics that can be collected from intermittent normal / full-band probing. Based on the minimum bandwidth determination, this mechanism can determine the optimal channel to be probed based on channel access and contention. In the second stage, the mechanism can perform probing in a portion of the frequency band and extrapolate channel estimates from that portion to the entire band.

[0012] As described above, to utilize channel prediction mechanisms, aspects of this paper may include a method for determining the minimum required bandwidth in a WLAN system that can be extrapolated to the entire bandwidth CSI. This method may include one or more of the following stages. First, the AP may probe across the entire bandwidth. In this stage, NDPs are transmitted across the entire bandwidth (e.g., 320 MHz). CSIs of clients responding to NDPs with BFRs can be collected based on standard procedures.

[0013] Secondly, the AP can find one or more tuples for N paths. A tuple is a parameter of the CSI, such as frequency-independent phase, whether the capture path is direct or reflected, path attenuation from the path, the distance the signal travels along the path to the antenna, the angle of arrival (AOA) of the signal along the path, etc. The parameters of the time-domain channel can be extracted from the full-band CSI. There are many tuples in the CSI. For example, there can be N x K x C x 4 tuple values, where N is the number of paths, K is the number of AP antennas, C is the number of clients, and 4 represents the number of individual parameter types received. For example, for five (5) paths, 16 antennas, four (4) clients, and four (4) types of tuples, there will be 1280 tuple values.

[0014] Third, from the tuple information, the AP can find the time delays for various paths: to calculate the required portion of bandwidth to be used for extrapolation or channel regeneration, the AP can evaluate the estimated distance traversed by each path, rather than converting it to actual time. There are likely two processes for determining the estimated distance. First, the distances in the tuple can be sorted. Then, the differences between distance pairs in the sorted list can be calculated. The AP can then determine the minimum difference among these calculations. In the second process, for all the differences calculated above, the average difference is calculated. The average difference is then determined based on the minimum value. This difference calculation helps identify the minimum delay interval between reflectors detected in the environment between the AP and each STA, which can be estimated at a 320 MHz bandwidth.

[0015] Fourth, the AP can determine the minimum bandwidth required for partial band detection based on the minimum distance difference metric calculated in the previous stage. The minimum required bandwidth can be determined by selecting a minimum bandwidth that provides sufficient resolution to distinguish two close signal peaks in the time delay curve. In implementation, to determine the bandwidth, the AP inverts the minimum time delay and then finds the closest larger bandwidth. For example, if the minimum delay between paths is 32 ns, the required bandwidth is 1 / 32 ns, equivalent to 31.25 MHz. The next larger portion of the bandwidth is 40 MHz; therefore, the AP selects a 40 MHz channel for partial band detection.

[0016] Finally, the AP can perform partial frequency band probing. First, the AP determines the number and specific sub-channels to use for probing. A minimum bandwidth of 40 MHz can be formed by two 20 MHz sub-channels. Clients can be associated with a large frequency band, thus the selected sub-channels can include the primary 20 MHz channel. If the primary 20 MHz channel is not selected, at least some clients may not be able to detect NDP. Maximum frequency diversity can be achieved by selecting the sub-channel with the largest frequency separation when selecting channels. In the Inverse Fast Fourier Transform (IFFT), zeros can be padded in the middle to achieve separation.

[0017] The AP can set a timer that triggers partial band probing to reassess the channel with the minimum required bandwidth. This time interval can be considered per client or for the entire network. It should be noted that small changes in client location can cause significant changes in the actual CSI. However, this algorithm re-estimates the travel time of the reflection path, which does not change significantly with small movements of the client antenna.

[0018] Probing can be performed in selected sub-channels within each probe interval. Then, tuple parameters for the entire channel are estimated based on partial band CSI, and CSI can be predicted (or extrapolated) for other sub-channels.

[0019] The methods described above may not require more frequent probes, and the probe intervals for a portion of the frequency band may be roughly the same as the time used for updating beamforming across the entire bandwidth (e.g., 50 ms). The benefits of this approach are at least twofold. First, the risk of contention and channel access in dense wireless environments is lower when only a portion of the entire frequency band is probed. Second, the overhead of transmitting back to the BFR is also reduced. In fact, probing half of the entire frequency band will inevitably halve CSI reports, and channel usage and probe latency will also be significantly reduced.

[0020] The aspects presented in this paper can also be applied to probes in multi-AP coordination scenarios. Probes in multi-AP coordination can require very high signaling and processing overhead. Using the methods presented in this paper can help to significantly reduce this overhead. In addition, the aspects presented in this paper can be combined with other probe optimization techniques, such as tone interleaving and orthogonal sequence-based reference signals (OSRS).

[0021] Wireless environment 100% Figure 1As shown. Wireless environment 100 may include a WLAN, which may be referred to as WLAN 100, network 100, wireless environment 100, etc., and may include one or more nodes, such as APs 102a, 102b, and / or 102c. Wireless environment 100 only shows three APs 102, but wireless environment 100 may include two or more APs 102. APs 102 can operate in a multi-AP coordinated environment. Therefore, APs 102 can communicate with each other to operate collaboratively.

[0022] AP 102 can communicate with one or more client sites 104a-104c, which may also be referred to simply as client 104 or site 104. Site 104 can be physically distributed across the physical area covered by AP 102 of WLAN 100. Site 104 and AP 102 can be wireless devices, such as when combined... Figure 6B The above can be a computing system, such as a combination of Figure 6A The network 100 may be controlled by a controller (not shown), such as a WLC, network controller, etc. The controller may be a computer system, wireless device, and / or other devices, such as those combined with… Figure 6A and 6B As stated above.

[0023] As described above and as Figure 1 As shown, the wireless network 100 may include Wi-Fi APs 102 (e.g., a first AP 102a and / or a second AP 102b), which may be configured to support the wireless (e.g., Wi-Fi) network 100. APs 102 may include physical locations where users operating client sites 104 can use Wi-Fi technology to gain access to the wireless network 100 (e.g., internet access) via a WLAN connected to a service provider's router.

[0024] In other examples(s) of this disclosure, access to wireless network 100 (e.g., internet access) may be provided instead of AP 102 using a device that can connect to a cellular network that can directly communicate with end-user equipment (e.g., client site equipment 104). Such devices may include, for example, eNodeBs (eNBs) or gNodeBs (gNBs). The aforementioned cellular networks may include, but are not limited to, Long Term Evolution (LTE) broadband cellular networks, fourth-generation (4G) broadband cellular networks, or fifth-generation (5G) broadband cellular networks operated by a service operator. Nevertheless, the examples of this disclosure may use wireless communication protocols, such as Wi-Fi technology, cellular networks, or any other type of wireless communication.

[0025] Client site device 104 may include, but is not limited to, telephones, smartphones, digital cameras, tablets, laptops, personal computers, mobile devices, sensors, Internet of Things (IoT) devices, cellular base stations, telephones, remote control devices, set-top boxes, digital video recorders, cable modems, network computers, mainframes, routers, or any other similar microcomputer-based device capable of accessing and using Wi-Fi or cellular networks.

[0026] The aforementioned components of the wireless network 100 (e.g., WLC, first AP 102a, second AP 102b, client devices 104a-104g, etc.) can be implemented in hardware, software (including firmware, resident software, microcode, etc.), a combination of hardware and software, or any other circuit or system. The components of the wireless network 100 can be implemented in circuits including discrete electronic components, packaged or integrated electronic chips containing logic gates (e.g., Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA), System-On-Chip (SOC), etc.), circuits utilizing microprocessors, or on a single chip containing electronic components or a microprocessor. Furthermore, the components of the wireless network 100 can also be implemented using other technologies capable of performing logical operations (e.g., AND, OR, and NOT), including but not limited to mechanical, optical, fluid, and quantum technologies. See below for reference. Figure 6A and 6B In more detail, the elements of the wireless network 100 may be implemented in the computing device 600 and / or the wireless device 630.

[0027] The implementation of signaling procedure 200 can be as follows: Figure 2 As shown. The first AP1 102a can initiate a detection process by sending a full-band detection signal to one or more stations 104a to 104n. The detection process may include sending NDPA to one or more stations 104a to 104n. The NDPA signal may be included in signals 202a-202n. After the NDPA, AP 102a may send NDP, which may be broadcast in SIFS. AP 102 may send the NDP in signals 202a-202n to stations 104a to 104n.

[0028] In response to the NDP in signals 202a-202n, stations 104a-104n can record information about the received signals and send CSI information back to AP 102a in signals 204a-204n. The CSI information can be included in the BFR from each client 104. This CSI information then allows AP 102a to determine the amount of bandwidth required for partial probes and which channels to probe. Based on these determinations, AP 102a can send partial band probe signals 206a-206n.

[0029] These partial frequency band signals 206a-206n can be part of the overall bandwidth, and similar NDPA / NDP can be used in these partial frequency bands or sub-channels. Signals 206a-206n can be sent to stations 104a to 104n, and stations 104a to 104n can return the BFRs of these probes in the sub-channels in the form of signals 207a-207n. Any information received back from stations 104a to 104n can be used to determine the movement of client 104 or to enable other functions of AP 102a.

[0030] In multi-AP coordination or other types of cooperation with another AP 102b, AP 102a can send CSI to AP 102b. Signal 208 provides AP 102b with CSI regarding probes to sites 104a to 104n from AP 102a. Based on this CSI, AP 102b can broadcast signals 210a-210n, which may also be in partial frequency bands. Signals 210a-210n can be sent to the same or different sites 104a to 104n. These partial frequency band probes from AP 102b can thus be broadcast without AP 102b needing to probe the entire bandwidth as AP 1 102a has done, because AP 102b has already benefited from the operations already performed by AP 1 102a. Any CSI from signal 204 and any response from signal 207 are provided to AP 102b. In this way, multi-AP coordination can reduce the overhead of detection from the second AP2 102b.

[0031] The implementation of one or more components associated with AP 102 can be as follows: Figure 3 As shown. AP 102 may include components 302, which may be part of or be implemented as part of computing system 600, such as Figure 6A As shown. These components 302 may include, but are not limited to, one or more of the following: full-band detection component 304, partial-band determiner 306, partial-band detection component 308, and / or AP coordination component 310.

[0032] The full-band detection component 304 can detect the full bandwidth of any or all channels or paths transmitted or received between AP 102 and one or more STAs 104. Full-band detection includes standard procedures for detecting channels to different sites 104. Thus, the full-band detection component 304 can transmit signal 202. The full-band detection component 304 can also receive CSI from signals 204 from various sites 104. This full-band detection component 304 can then pass channel state information to the partial band determiner 306.

[0033] Partial band determiner 306 can determine which partial frequency band to use for partial band detection. Partial band determiner 306 can be based on the following... Figure 4 and Figure 5 One or more algorithms provided in the specification select the amount of bandwidth required for partial band detection. Partial band determiner 306 can also select which sub-channels can be used for partial band detection. This bandwidth and / or sub-channel information can then be provided to partial band detection component 308.

[0034] Partial band detection component 308 can perform partial band detection by transmitting signal 206 and receiving BFR response 207 returned from STA 104. Partial band detection can occur on one or more sub-channels instead of the entire bandwidth. In this way, partial band detection component 308 can perform detection in a different manner than full band detection component 304.

[0035] The multi-AP coordination component 310 can coordinate with another AP 102 (e.g., AP2 102b) to provide or receive CSI or other information from that AP2 102b. The provided CSI allows the second AP2 102b to perform partial-band probing, such as transmitting signal 210, without requiring full-band probing, such as 202. Thus, the AP coordination component 310 allows for more streamlined probing from APs within the multi-AP coordination protocol and reduces the overall overhead of the WLAN 100.

[0036] Now for reference Figure 4 Method 400, according to various aspects of this disclosure, can provide a method for determining the minimum bandwidth required for detection. Method 400 can begin with a start operation and can end with a stop operation. Method 400 may include more or fewer stages, or may be structured differently from... Figure 4The sequence of the stages is arranged as shown. Method 400 can be executed as a set of computer-executable instructions, executed by a computer system or processing component, and encoded or stored on a storage medium. Alternatively, method 400 can be executed by gates or other hardware devices or components in an ASIC, FPGA, SOC, or other type of hardware device. In the following description, method 400 will be explained with reference to the systems, components, modules, software, data structures, etc., described herein.

[0037] In phase 402, AP 102 can probe the entire bandwidth. Full-band detection component 304 can probe the entire bandwidth of one or more channels between AP 102 and station 104. This full-band detection may include a signal 202 transmitted to one or more stations 104. This full-band detection may transmit NDPA, followed by NDP transmitted in a post-NDPA SIFS. AP 102 may receive CSI, for example, in one or more BFRs. Responses from STA 104 may be received as signal 204. CSI may be provided to partial band determiner 306.

[0038] Channel estimation for the entire bandwidth or baseband channel can depend on the following algorithm: In the above formula, θ n It is the AOA of the signal along path n. d n It is the distance the signal travels along path n to the first antenna. I It refers to the pair separation between antennas on the base station. λ It's the wavelength. a_n It is the path decay from the nth path, and Φ n This is a frequency-independent phase used to determine whether the path is direct or reflected. Knowledge of at least some parameters (e.g., tuples) in this formula for a portion of the frequency band can help estimate the same tuples across the entire band. For example, a_n , Φ n、 θ n and d n It is possible to extrapolate from a portion of the frequency band to the entire baseband. These example tuples may be frequency-invariant and can provide knowledge of channel estimation, i.e., providing information within a frequency range. h i Then regenerate / predict at another frequency h i .

[0039] Then, in stage 404, AP 102 can find one or more tuples for one or more paths. Partial band determiner 306 can extract one or more tuples from the CSI received in signal 204. The process can be based on time-domain CSI (e.g., IFFT of frequency-domain CSI) and can solve an optimization problem to minimize the error between estimated channels based on the estimated tuples. In some implementations, machine learning algorithms can solve the optimization problem and predict the channels for other antennas.

[0040] As described above, the tuples (one or more) may include, but are not limited to, one or more of the following: whether the capture path is a direct or reflected frequency-independent phase, the AOA of the signal along the path, the distance the signal travels along the path to the first antenna, and / or path attenuation from the path. These four tuples can be extracted from various paths. The path is the communication link between AP 102 and site 104. Therefore, for each AP 102, there can be time-domain channel parameters extracted from the full-band channel state information.

[0041] The number of values ​​in the Channel State Information (CSI) extracted by the full-band detection component 304 can depend on the number of n paths multiplied by the number of receiving antennas K, then multiplied by the number of clients, and then multiplied by the number or type of tuples (e.g., four tuples). Thus, for example, if there are five paths, 16 antennas, four clients, and four tuples, then 1280 values ​​will be extracted from the CSI. This CSI information can be temporarily stored by the partial-band detection component 308 or the full-band detection component 304.

[0042] Then, in stage 406, AP 102 can determine the time delay of the path. Partial band determiner 306 can then determine the time delay for path(s). This time delay can be estimated by partial band determiner 306. This time delay is used to determine the minimum amount of bandwidth required for partial band detection. This time delay can be calculated as follows: First, each path and the signal travel distance for each client 104 is sorted. Then, the difference in time delay is calculated from these distances by subtracting the distance of one path from the distance of the next distance in the sorted list. These calculations attempt to find the minimum distance between two entries in the sorted list. All distance pairs in the sorted list can be subtracted until the minimum distance or minimum difference found between two distances is determined. In another implementation, the determined differences calculated above can then be averaged. This average can be reflected as the minimum distance. The minimum distance difference can then be modified into time by multiplying by the speed of the signal (e.g., the speed of light). Based on this time delay, partial band determiner 306 can determine the minimum bandwidth required for partial band detection.

[0043] Then, in stage 408, AP 102 can determine the minimum bandwidth required for partial band detection. In stage 406, partial band determiner 306 can find the minimum required bandwidth based on the determined minimum distance / time delay. The minimum bandwidth is defined as bandwidth with sufficient resolution to distinguish two peaks in the time delay curve based on the previously provided distance. In one implementation, the minimum bandwidth is determined by inverting the minimum time delay derived in stage 406 and then finding the closest larger sub-channel bandwidth subdivision. For example, if the minimum time delay determined in stage 406 is 32 ns, the required bandwidth would be 1 / 32 ns, equivalent to 31.25 MHz. Since there is no 31.25 MHz channel subdivision, the next largest channel subdivision is 40 MHz (e.g., composed of two 20 MHz sub-channels). Therefore, 40 MHz is the minimum bandwidth required to provide appropriate resolution for partial band detection.

[0044] According to various aspects of this disclosure, the method 500 for detection in a certain frequency band can be implemented as follows: Figure 5 As shown. Method 500 can begin with a start operation and can end with a finish operation. Method 500 may include more or fewer stages, or may be different from... Figure 5 The sequence of the stages is arranged as shown. Method 500 can be executed as a set of computer-executable instructions, executed by a computer system or processing component, and encoded or stored on a storage medium. Alternatively, method 500 can be executed by gates or other hardware devices or components in an ASIC, FPGA, SOC, or other type of hardware device. In the following description, method 500 will be explained with reference to the systems, components, modules, software, data structures, etc., described herein.

[0045] Based on the minimum bandwidth required for partial band probing calculated in method 400, in stage 502, AP102 can select one or more sub-channels for partial band probing. Partial band determiner 306 can select one or more sub-channels required for partial band probing. The number of selected sub-channels is based on the bandwidth in each sub-channel multiplied by the number of sub-channels needed to provide more bandwidth than the minimum required bandwidth determined in method 400. For example, if 40 MHz of bandwidth is required for partial band probing, partial band determiner 306 can select two 20 MHz channels for partial band probing. These 20 MHz sub-channels can be extracted from the full 160 MHz bandwidth.

[0046] The selection of which channels to use can also be determined by the partial band determiner 306. For example, the partial band determiner 306 can select primary and secondary channels in the middle of a 160 MHz bandwidth range. These sub-channels are selected in the middle of the bandwidth range to provide maximum diversity across the entire full bandwidth frequency range. Thus, the partial bandwidth determiner 306 can select sub-channels for maximum frequency separation. This selection of sub-channels can then be provided to the partial band detection component 308.

[0047] In phase 504, AP 102 can also determine the repetition interval of the probe. The partial band determiner 306 can set the repetition interval of the probe. The repetition interval can generate a timer that triggers a reassessment of the sub-channel. This time interval can be selected on a per-client 104 basis or across the entire network based on client 104. Small changes in the location of one or more clients can cause significant changes in the CSI. However, the algorithm described above can determine that the probe needs to be reassessed using the past travel time of the reflection, which will not change significantly based on small movements of the client antennas. Therefore, the interval timer can be set at a frequency or period greater than that required to adjust for small movements of client 104. This timing interval is also sent to the partial band probe component 308.

[0048] Then, in stage 506, AP 102 can determine whether the timing interval has expired. Partial band detection component 308 can monitor the time interval clock. Once the clock expires, partial band detection component 308 can determine that partial band detection is required. Thus, once the time interval expires, method 500 proceeds to stage 508 via "Yes". However, if the time interval has not yet expired, method 500 will return via "No" to continue waiting for the interval to expire.

[0049] In phase 508, AP 102 probes a portion of the frequency band for one or more clients 104. Thus, the portion-band probe component 308 can probe the sub-channels selected by the portion-band determiner 306 after a probe interval. For the portion-band CSI, estimate one or more tuples (e.g., the four tuples mentioned above), or parameters from the channel. This portion-band CSI can be extrapolated or used to predict the CSI or channel estimate of other sub-channels or the entire wide channel. Therefore, based on the portion-band channel probe information, the portion-band probe component 308 can determine channel state information or extrapolate this information for the entire channel. This information can then be used to update the beamforming requirements of AP 102. If a portion of the frequency band has been probed, method 500 can return to wait for that interval or return to phase 502. This significantly reduces the amount of bandwidth or resources required for probes. Further probe delays are also significantly reduced. However, channel state information for the entire frequency band is provided.

[0050] This partial band sensing can also be used in multi-AP coordination. In this way, one or more APs 102a can share channel state information from a portion of the frequency band, or perform partial band sensing for one or more clients 104 at some APs 102. Then, multiple APs 102 can use partial band CSI, resulting in overall network overhead savings.

[0051] Figure 6A A computing device 600 is shown. (For example...) Figure 6A As shown, computing device 600 may include a processing unit 610 and a memory unit 615. Memory unit 615 may include software module 620 and database 625. When executed on processing unit 610, software module 620 may perform processes, for example, for changing beamwidth for some operations in multi-AP coordination, as referenced above. Figures 1-5 The computing device 600 may provide an operating environment for, for example, a controller, AP 102, client 104, or other devices; however, the controller, AP 102, client 104, and other devices may operate in other environments and are not limited to the computing device 600.

[0052] The computing device 600 can be implemented using Wi-Fi access points, cellular base stations, tablet devices, mobile devices, smartphones, telephones, remote control devices, set-top boxes, digital video recorders, cable modems, personal computers, network computers, mainframes, routers, switches, server clusters, smart TV-like devices, network storage devices, network relay devices, or other similar microcomputer-based devices. The computing device 600 can include any computer operating environment, such as handheld devices, multiprocessor systems, microprocessor-based or programmable transmitter electronics, microcomputers, mainframes, etc. The computing device 600 can also be implemented in a distributed computing environment, where tasks are performed by remote processing devices. The systems and devices described above are examples, and the computing device 600 can include other systems or devices.

[0053] Figure 6B The diagram illustrates how this can be achieved. Figures 1-5 The implementation of communication device 630 includes one or more of AP 102, client 104, controller, etc. In various implementations, device 630 may include logic circuitry. The logic circuitry may include physical circuitry to perform, for example... Figures 1-5 The operations described in one or more of the AP 102, client 104, controller, etc. For example... Figure 6B As shown, device 630 may include, but is not limited to, one or more of radio interface 635, baseband circuitry 640, and / or computing platform 600.

[0054] Device 630 can be implemented in a single computing entity (e.g., entirely within a single device). Figures 1-5 The AP 102, client 104, controller, etc., storage media, and logic circuitry, some or all of their structures and / or operations. Alternatively, the device 630 may use a distributed system architecture (e.g., client-site-server architecture, peer-to-peer architecture, master-slave architecture, etc.) to distribute some parts of the structures and / or operations.

[0055] The radio interface 635, which may also include an analog front end (AFE), may include components or combinations of components suitable for transmitting and / or receiving single-carrier or multi-carrier modulated signals (e.g., including Complementary Code Keying (CCK), Orthogonal Frequency Division Multiplexing (OFDM), and / or Single-Carrier Frequency Division Multiple Access (SC-FDMA) symbols), although the configuration is not limited to any particular air interface or modulation scheme. The radio interface 635 may include, for example, a receiver 645 and a transmitter 650. The radio interface 635 may include bias control, a crystal oscillator, and / or one or more antennas 655. In additional or alternative configurations, the radio interface 635 may use an oscillator and / or one or more filters as needed.

[0056] The baseband circuitry 640 can communicate with the radio interface 635 to process, receive, and / or transmit signals, and may include, for example, an analog-to-digital converter (ADC) for down-converting received signals, and a digital-to-analog converter (DAC) 660 for up-converting signals for transmission. Additionally, the baseband circuitry 640 may include baseband or physical layer (PHY) processing circuitry for PHY link layer processing of various received / transmitted signals. The baseband circuitry 640 may, for example, include Media Access Control (MAC) processing circuitry 665 for MAC / data link layer processing. The baseband circuitry 640 may include a memory controller for communicating, for example, with the MAC processing circuitry 665 and / or the computing platform 600 via one or more interfaces 670.

[0057] In some configurations, the PHY processing circuitry may include frame construction and / or detection modules, combined with additional circuitry such as buffer memory, for constructing and / or decomposing communication frames. Alternatively or additionally, the MAC processing circuitry 665 may perform these processes for some shared processing of these functions or independently of the PHY processing circuitry. In some configurations, MAC and PHY processing may be integrated into a single circuit.

[0058] Examples of this disclosure may be implemented as a computer process (method), a computing system, or as an article of manufacture such as a computer program product or a computer-readable medium. A computer program product may be a computer storage medium that is readable by a computer system and encodes a computer program containing instructions for performing a computer process. A computer program product may also be a propagated signal on a carrier of a computer program that is readable by a computing system and encodes instructions for performing a computer process. Therefore, this disclosure may be embodied in hardware and / or software (including firmware, resident software, microcode, etc.). In other words, examples of this disclosure may take the form of a computer program product on a computer-usable or computer-readable storage medium that embodies computer-usable or computer-readable program code for use by or in connection with an instruction execution system. A computer-usable or computer-readable medium may be any medium capable of containing, storing, communicating, propagating, or transmitting a program for use by or in connection with an instruction execution system, apparatus, or device.

[0059] Computer-usable or computer-readable media can be, for example, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, devices, or propagation media. More specific examples of computer-readable media (not an exhaustive list) include: electrical connections having one or more wires, portable computer disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, and compact discread-only memory (CD-ROM). Note that computer-usable or computer-readable media can even be paper or another suitable medium on which a program is printed, because the program can be electronically captured, for example, by optical scanning of the paper or other medium, and then, if necessary, compiled, interpreted, or otherwise processed in an appropriate manner, and subsequently stored in computer memory.

[0060] While some examples of this disclosure have been described, other examples are possible. Furthermore, although the examples of this disclosure have been described as relating to data stored in memory and other storage media, data may also be stored on or read from other types of computer-readable media, such as secondary storage devices like hard disks, floppy disks, or CD-ROMs, carrier waves from the Internet, or other forms of RAM or ROM. Additionally, the stages of the disclosed methods may be modified in any way, including through reordering stages and / or insertion or deletion stages, without departing from this disclosure.

[0061] Furthermore, the examples of this disclosure can be implemented in circuits including discrete electronic components, in packages or integrated electronic chips containing logic gates, in circuits utilizing microprocessors, or on a single chip containing electronic components or a microprocessor. The examples of this disclosure can also be implemented using other techniques capable of performing logical operations (e.g., AND, OR, and NOT), including but not limited to mechanical, optical, fluid, and quantum technologies. Furthermore, the examples of this disclosure can be implemented within a general-purpose computer or in any other circuit or system.

[0062] The examples disclosed herein can be implemented via a SOC, where Figure 1 Each or many of the components shown can be integrated onto a single integrated circuit. Such a SoC device may include one or more processing units, graphics units, communication units, system virtualization units, and various application functions, all of which can be integrated (or “programmed”) onto a chip substrate as a single integrated circuit. When operating via the SoC, the functions described herein with respect to the examples of this disclosure can be executed via dedicated logic integrated onto a single integrated circuit (chip) along with other components of the computing device 600.

[0063] For example, the examples of this disclosure have been described above with reference to block diagrams and / or operational illustrations of methods, systems, and computer program products according to the present disclosure. The functions / behaviors described in the blocks may not occur in the order shown in any flowchart. For example, depending on the functions / actions involved, two blocks shown consecutively may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order.

[0064] Although this specification includes examples, the scope of this disclosure is indicated by the appended claims. Furthermore, although this specification has been described in language specific to structural features and / or methodological actions, the claims are not limited to the features or actions described above. Rather, the specific features and actions described above are disclosed as examples of this disclosure.

Claims

1. A method for communication, comprising: The access point (AP) selects a sub-channel for the partial probe based on the minimum bandwidth required for the partial probe. The selected sub-channel is detected by the AP; The AP receives the first channel state information (CSI) of the station STA in response to the probe; Based on the first CSI from the selected sub-channel, the AP extrapolates the first CSI to determine the predicted second CSI for a wider bandwidth channel; as well as The minimum bandwidth is determined by the AP, wherein determining the minimum bandwidth includes: The entire bandwidth is detected by the AP; The AP receives a third CSI from the STA in response to the probe of the entire bandwidth; The AP extracts the path tuple from the third CSI; and Based on the tuple, the AP determines the time delay, wherein the minimum bandwidth is the reciprocal of the time delay.

2. The method as described in claim 1, wherein, The selected sub-channel is the main sub-channel near the middle of the larger bandwidth of the baseband channel.

3. The method as described in any of the preceding claims, wherein, Detecting the sub-channel includes: Broadcast Null Data Packet Announcement (NDPA) on the sub-channel; In the short interframe interval SIFS following the NDPA, the NDP (Null Data Packet) is broadcast; and Receive beamforming report (BFR) from the client in response to the NDP.

4. The method as described in any of the preceding claims, wherein, The first CSI from the partial probe comprises two or more tuples, wherein the two or more tuples are extracted from the first CSI.

5. The method as described in any of the preceding claims, wherein, The minimum bandwidth provides resolution between signal peaks in the time delay curve.

6. The method of claim 5, wherein, The minimum bandwidth is greater than the bandwidth of the selected sub-channel, and at least two sub-channels are selected to probe the minimum bandwidth.

7. The method of claim 1, wherein, The time delay is based on the difference between a first estimated distance traveled by the first signal and a second estimated distance traveled by the second signal.

8. A device for communication, comprising a processing unit and a storage unit, the processing unit being operable to: The sub-channel for the partial probe is selected based on the minimum bandwidth required for the partial probe. Probe the selected sub-channel; In response to the probe, the station STA receives its first channel state information (CSI). Based on the first CSI from the selected sub-channel, the first CSI is extrapolated to determine the predicted second CSI for a wider bandwidth channel; and Determining the minimum bandwidth includes: Detect the entire bandwidth; A third CSI is received from the STA in response to the detection of the entire bandwidth; Extract the path tuple from the third CSI; and Based on the tuple, a time delay is determined, wherein the minimum bandwidth is the reciprocal of the time delay.

9. The device as claimed in claim 8, wherein, The processing unit can also be operated to perform the method as described in any one of claims 2 to 7.

10. A computer-readable medium storing a set of instructions, which, when executed, cause to perform a method comprising: The sub-channel for the partial probe is selected based on the minimum bandwidth required for the partial probe. Probe the selected sub-channel; In response to the probe, the station STA receives its first channel state information (CSI). Based on the first CSI from the selected sub-channel, the first CSI is extrapolated to determine the predicted second CSI for a wider bandwidth channel; and Determining the minimum bandwidth includes: Detect the entire bandwidth; A third CSI is received from the STA in response to the detection of the entire bandwidth; Extract the path tuple from the third CSI; and Based on the tuple, a time delay is determined, wherein the minimum bandwidth is the reciprocal of the time delay.

11. The computer-readable medium of claim 10, wherein the set of instructions, when executed, causes the method of any one of claims 2 to 7 to be performed.

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