Coordinated beamforming in an overlapping basic service set

Abstract

A system and method for coordinating cooperative beamforming (co-bf) in an overlapping basic service set (bss) are disclosed. The method includes the step of detecting an overlapping bss between a first ap and a second ap by a first access point (ap), and the step of transmitting an indication by the first ap that the first ap has received a cross-bss channel state information (csi) report. Additionally, the method includes the step of performing co-bf by the first ap in cooperation with the second ap based on the cross-bss csi report.

Description

Technology Field

[0001] The present disclosure generally relates to wireless systems. More specifically, the subject matter disclosed herein relates to improvements in coordinated beamforming (Co-BF) in an overlapping basic service set (OBSS). Background Technology

[0002] In a wireless network, an access point (AP) can operate as a hub for multiple wireless network devices referred to as stations (STAs). The STAs are generally located within the service area of ​​an associated AP. STAs can be of various forms, such as fixed, mobile, or semi-fixed. The STAs can be communically coupled with at least an associated AP. That is, a specific STA may be associated with only one AP, but may also communicate with unassociated APs. Furthermore, STAs associated with a specific AP generally do not communicate directly with each other within the wireless network. However, STAs may have additional short-range wireless capabilities, such as Bluetooth, non-AP-based Wi-Fi networks, or ad-hoc mesh networks. A specific STA may be located within the service area of ​​two or more APs. For example, a single STA may be simultaneously located in a first service area associated with a first AP (AP1) and a second service area associated with a second AP (AP2).

[0003] FIG. 1 is a schematic diagram of an overlapping basic service set (OBSS) (100) between AP1 and AP2 according to one embodiment.

[0004] Referring to FIG. 1, two STAs are shown, one of which is located within a service area associated with both AP1 and AP2. However, the STA is associated only with AP1.

[0005] It should be noted that different terms may be used for similar functions depending on the standard. Therefore, "access point" or "AP" may be used interchangeably with other terms such as "base station." As described herein, a wireless network consisting of an AP and its associated STA may be referred to as a Basic Service Set (BSS). Additionally, the term "OBSS" may refer to wireless networks that overlap at least partially. From a geographical perspective, OBSS may be understood as service areas that overlap with each other.

[0006] An AP may be any configuration of hardware and software including backhaul equipment for connecting to a wired network, a baseband processor for processing baseband signals, a modulator / demodulator for modulating and demodulating between the baseband signal and a transmit / receive signal (e.g., a received or signal scheduled to be transmitted), and an antenna for transmitting and receiving the transmit / receive signal. The antenna may include, for example, an array antenna capable of forming the antenna's radiation pattern into a directional communication beam by utilizing constitutive interference between signals radiated from multiple radiating elements in an array.

[0007] Due to OBSS, interference may occur in the transmitted signals between a single STA and two or more APs. Co-BF allows APs belonging to the OBSS to coordinate their respective transmissions. Accordingly, Co-BF can reduce interference between transmitted signals.

[0008] Additionally, one of the APs in the OBSS may provide relatively superior service to a specific STA compared to other APs. For example, AP1 may provide lower latency or higher signal strength than AP2. Accordingly, the Co-BF technique may determine that AP1 should provide service to the corresponding STA.

[0009] Additionally or alternatively, Co-BF can coordinate multiple APs to simultaneously provide service to a STA. That is, Co-BF can enable simultaneous transmission from two or more APs to the STA associated with each AP while minimizing or reducing interference to the OBSS. However, for effective Co-BF, information about the transmission characteristics of each AP may be required.

[0010] To resolve this issue, one AP can transmit a Cross BSS Channel State Information (CSI) report to another AP. Accordingly, AP1 and AP2 can share the Cross BSS CSI report. Additionally, or alternatively, the AP can overhear a Cross BSS report from a non-associated STA. The said Cross BSS CSI report can be used to ensure proper Co-BF.

[0011] One of the problems with the above approach is that, in some cases, cross-BSS CSI reports may not be received. As a result, Co-BF cannot be coordinated, which can lead to persistent interference. The problem to be solved

[0012] To solve the above problem, the present specification describes a system and method for transmitting a reception indication from one AP to another AP that indicates that a cross BSS CSI has been received.

[0013] The above approach provides an improved effect compared to conventional methods in that error-prone Co-BF procedures can be prevented. means of solving the problem

[0014] In one embodiment, the method includes the step of detecting an OBSS between AP1 and AP2 by AP1, and the step of transmitting an indication by AP1 whether AP1 has received a cross-BSS CSI report. The method includes the step of coordinating with AP2 to perform a Co-BF procedure based on the cross-BSS CSI report by AP1.

[0015] In one embodiment, the system includes AP1 having AP2 and OBSS, and AP1 is configured to transmit an indication of whether it has received a cross-BSS CSI report from AP2. AP1 is further configured to coordinate with a second AP to perform a Co-BF procedure based on the cross-BSS CSI report.

[0016] In one embodiment, the AP includes a transceiver configured to communicate with another AP, and a processing circuit connected to communicate with the transceiver, wherein the processing circuit detects an overlapping BSS with the other AP, transmits to the other AP via the transceiver an indication of whether the AP has received a cross-BSS CSI report, and is configured to initiate a Co-BF procedure based on the cross-BSS CSI report.

[0017] In one embodiment, the AP includes a transceiver configured to communicate with another AP and a processing circuit connected to communicate with the transceiver. The processing circuit detects an overlapping BSS with the other AP and receives either an indication that the other AP has received a cross-BSS CSI report or an indication that the other AP has received a cross-BSS CSI report request from the other AP, and is configured to transmit the cross-BSS CSI report to the other AP via the transceiver based on an indication of whether the other AP has received the cross-BSS CSI report or a request for the cross-BSS CSI report, and to initiate a Co-BF procedure based on the cross-BSS CSI report. Brief explanation of the drawing

[0018] Hereinafter, various aspects of the subject matter disclosed in this specification will be described with reference to exemplary embodiments illustrated in the attached drawings: FIG. 1 is a schematic diagram of OBSS (100) between AP1 and AP2 according to one embodiment. FIG. 2 is a transmission diagram (200) for Co-BF according to one embodiment. FIG. 3 is a transmission diagram (300) for a cross-BSS status request and report from an initiation AP according to one embodiment. FIG. 4 is a transmission diagram (400) for a cross BSS CSI report from an initiation AP according to one embodiment. FIG. 5 is a transmission diagram (500) for bidirectional cross-BSS CSI reporting, request, or confirmation according to one embodiment. FIG. 6 is a transmission diagram (600) for a bidirectional cross-BSS CSI report, request, or confirmation according to one embodiment. FIG. 7 is a transmission diagram (700) for a cross BSS CSI status request by an initiation AP according to one embodiment. FIG. 8 is a transmission diagram (800) for a cross-BSS CSI report from an initiation AP including retransmission according to one embodiment. FIG. 9 is a transmission diagram (900) for cross BSS CSI verification according to one embodiment. FIG. 10 is a transmission diagram (1000) for a cross BSS CSI request from a response AP according to one embodiment. FIG. 11 illustrates a Co-BF method in OBSS according to one embodiment. FIG. 12 is a block diagram of an electronic device in a network environment according to one embodiment. FIG. 13 illustrates a system (1300) including STA (1330) and AP (1310) communicating with each other according to one embodiment. Specific details for implementing the invention

[0019] In the following detailed description, many specific details are described to provide a complete understanding of the present disclosure. However, those skilled in the art will understand that the disclosed aspects may be practiced without these specific details. In other examples, well-known methods, procedures, components, and circuits have not been described in detail to avoid obscuring the subject matter disclosed herein.

[0020] Throughout this specification, references to “one embodiment” or “one embodiment” mean that specific features, structures, or characteristics described in relation to an embodiment may be included in at least one embodiment disclosed in this specification. Accordingly, references to “in one embodiment,” “in one embodiment,” or “according to one embodiment” (or other phrases having a similar meaning) in various places throughout this specification may not all refer to the same embodiment. Furthermore, specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In this regard, as used in this specification, the word “exemplary” means “serves as an example, instance, or illustration.” Any embodiment described as “exemplary” in this specification should not be interpreted as necessarily being preferred or advantageous over other embodiments. Additionally, specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Also, depending on the context of this discussion, singular terms may include their corresponding plural forms, and plural terms may include their corresponding singular forms. Similarly, hyphenated terms (e.g., "2-dimensional," "pre-determined," "pixel-specific," etc.) may occasionally be used interchangeably with their corresponding unhyphenated versions (e.g., "2-dimensional," "pre-determined," "pixel-specific," etc.), and uppercase items (e.g., "Counter Clock," "Row Select," "PIXOUT," etc.) may be used interchangeably with their corresponding non-uppercase versions (e.g., "counter clock," "row select," "pixout," etc.). Such interchangeable use should not be considered inconsistent.

[0021] It should also be noted that the various drawings (including components) shown and discussed in this specification are for illustrative purposes only and are not drawn in proportion. For example, the dimensions of some elements may be exaggerated relative to others for clarity. Additionally, where deemed appropriate, reference numbers are repeated between drawings to indicate corresponding and / or similar elements.

[0022] The terms used herein are intended to describe some exemplary embodiments and are not intended to limit the essence of the claimed disclosure. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. It will be understood that when used herein, the terms “comprising” and / or “comprising” specify the presence of the mentioned features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0023] When one element or layer is referred to as being "connected" or "combined" to another element or layer, it may be directly above, connected to, or combined with respect to the other element or layer, or an intermediate element or layer may exist. In contrast, when one element is referred to as being "directly above," "directly connected," or "directly combined" to another element or layer, no intermediate element or layer exists. The same number indicates the same element throughout. As used herein, the terms "or" and "and / or" include any and all combinations of one or more associated enumerated items.

[0024] Terms used herein, such as “first,” “second,” etc., are used as labels preceding nouns and do not imply any type of order (e.g., spatial, temporal, logical, etc.) unless explicitly defined. Additionally, the same reference number may be used across two or more drawings to refer to parts, components, blocks, circuits, units, or modules having the same or similar functions. However, such usage is intended for simplicity of description and ease of discussion; it does not imply that the structure or structural details of such components or units are the same across all embodiments, or that a commonly referenced part / module is the only way to implement a part of the exemplary embodiments disclosed herein.

[0025] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this subject belongs. It will be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with that meaning in the context of the relevant technology, and should not be interpreted in an idealized or overly formal sense unless explicitly defined in this specification.

[0026] As used herein, the term “module” refers to any combination of software, firmware, and / or hardware configured to provide the functions described herein in relation to the module. For example, software may be implemented as a software package, code and / or instruction set or instructions, and as used in any implementation described herein, the term “hardware” may include, for example, assemblies, hardwired circuits, programmable circuits, state machine circuits, and / or firmware storing instructions executed by programmable circuits, for example, in a single or any combination. Modules may be implemented collectively or individually as circuits forming part of a larger system, such as an integrated circuit (IC), a system-on-chip (SoC), an assembly, etc.

[0027] The quality of transmission between the AP and the STA can be represented by a channel state information (CSI) report. The CSI report may include physical layer measurement information regarding the state of the transmission channel. The CSI report may include information related to the fading, scattering, power attenuation, etc., of the signal propagating through the channel. The CSI report may be generated based on statistical values, instantaneous values, or similarly determined values. The CSI report may be based on a channel state estimation procedure that utilizes, for example, a CSI reference signal (e.g., a pilot signal) transmitted through the channel. The CSI report may indicate how well the STA can receive the signal transmitted from the AP. The CSI reference signal may be used in sounding techniques.

[0028] The sounding technique may include a process in which the AP transmits a pilot signal to the STA, and subsequently the STA responds with information regarding how well the pilot signal was received. The measurement performed and the information provided by the STA may be referred to as CSI feedback.

[0029] Sequential sounding may refer to transmitting pilot signals through a specific channel, such as between a specific transmitting antenna and a receiving antenna, to generate a CSI report for that channel. In sequential sounding, pilot signals may be transmitted from different APs at different times.

[0030] In joint sounding, pilot signals are transmitted simultaneously to multiple STAs. The STAs can respond either simultaneously or sequentially with information on how well the pilot signals were received. Joint sounding can be more efficient than sequential sounding.

[0031] Cross BSS sounding may include a process in which the AP transmits a signal to a non-associated STA located in the same overlapping service area, and then provides information on how well the non-associated STA received the signal.

[0032] Cross-BSS CSI reports can be used by APs to perform Co-BF procedures. More specifically, APs can perform Co-BF by generating and sharing cross-BSS CSI reports using sequential sounding and / or co-sounding. These procedures may be defined by standards. For example, the IEEE P802.11bn / D0.1 standard defines an explicit feedback mechanism for in-BSS sounding and cross-BSS sounding to measure and report CSI, such as Ultra-High Reliability Trigger-Based (UHR TB) sequential / co-null data packet (NDP) sounding. However, following these standard procedures may lead to problems where a specific AP fails to obtain the cross-BSS CSI report from the associated STA, or does not know whether another AP has received the cross-BSS CSI.

[0033] FIG. 2 is a transmission diagram (200) according to one embodiment.

[0034] Referring to FIG. 2, the transmission diagram (200) includes horizontal lines labeled AP1, AP2, STA1, and STA2, respectively, to represent the first and second APs and the first and second STAs, respectively. The horizontal lines of the STAs and APs represent a network of devices communicating with each other. The transmission diagram (200) also includes a short sequence (210) and a long sequence (220) covering four devices. The long sequence (220) may consist of a multi-AP coordination (MAPC) / Co-BF search and negotiation process including a management frame / action frame.

[0035] The short sequence (210) may include an initial information exchange (212) including an initial control frame (ICF) and an initial control response (ICR), and any appropriate initialization protocol related to coordinating transmission may be used. The ICF and ICR may be transmitted between APs. Additionally, the ICF and ICR may also be transmitted between an AP and an in-BSS STA. The short sequence (210) also includes in-BSS and cross-BSS sounding and CSI reports (214). The in-BSS and cross-BSS sounding and CSI reports (214) may include a sequential sounding step (214a), an in-BSS CSI report (214b), and a cross-BSS CSI report (214c). The sequential sounding step (214a) may be configured as an invitation / response sounding method between APs to perform null data packet (NDP) sounding with the same BSS STA and the cross BSS STA. After the same BSS CSI report (214b) and the cross BSS CSI report (214c) are obtained, an invitation / response may be transmitted between the APs. Additionally, a trigger may be transmitted to the STA to initiate data transmission.

[0036] Accordingly, the short sequence (210) may further include Co-BF data transmission (216). As illustrated, Co-BF data transmission (216) may include a trigger, a DL, a physical layer protocol data unit (PPDU), a block acknowledgment request (BAR), and a block acknowledgment (BA). For example, a Co-BF AP may transmit a multi-user BAR (MU-BAR) to request a BA from the STA associated with the initiating AP and the responding AP. After or during the sequential / co-sounding process, the initiating AP and the responding AP may each acknowledge the receipt of the CSI report within the BSS and the cross-BSS CSI report and prepare to perform Co-BF data transmission. Accordingly, Co-BF may be performed with each AP possessing the same BSS CSI report and the cross-BSS CSI report from the same BSS (associated) STA and the cross-BSS (unassociated) STA, respectively. The AP may obtain the cross-BSS CSI report via various communication methods.

[0037] For example, an AP can overhear CSI feedback from a non-associated STA wirelessly (over-the-air). This method has the advantage of requiring no additional airtime for cross-BSS CSI reports and having low overhead. Overhearing can be used, for example, during security setup processes or to ensure good link quality between the AP and a non-associated STA.

[0038] Additionally or alternatively, an AP can transmit CSI feedback to other APs wirelessly. When transmitting CSI feedback wirelessly, overhearing or backhaul functions may not be required, and processing and complexity can be shifted to the AP side. In some cases, wireless transmission may be more reliable than overhearing. Wireless transmission of CSI feedback can be used for wireless communication between APs. For example, wireless communication may be used when additional airtime is permitted for cross-BSS setup or CSI reporting.

[0039] Additionally, as an alternative, APs can transmit CSI feedback to other APs via wired backhaul. Transmitting CSI feedback via wired backhaul eliminates the need for additional airtime for cross-BSS CSI reports and enables transmission with low overhead. Transmission via wired backhaul can provide higher reliability than overhearing or wireless transmission methods. CSI feedback transmission via wired backhaul can be applied in environments where wired backhaul connections exist between APs and signal exchange and coordination occur between the wired backhaul and wireless connections.

[0040] In all three of the above communication modes, each AP can check the current status with the counterpart AP to transmit and / or receive cross-BSS CSI feedback. The current status may be, for example, a state ready to transmit a cross-BSS CSI report, a state in which a compressed beamforming / channel quality indicator (CQI) frame (same BSS / cross BSS) has been received, a state ready to transmit Co-BF data, etc.

[0041] Additionally or alternatively, each AP may notify or trigger the associated Co-BF non-AP STA regarding the current state and / or next action. For example, each AP may notify or trigger that both APs have received a compressed beamforming / CQI frame (same BSS / cross BSS), that both APs are ready to perform Co-BF data transmission, and that the associated non-AP STAs should be prepared for sounding, CSI feedback, Co-BF data transmission, and block acknowledgment (BA).

[0042] The AP may initiate a cross-BSS CSI reporting sequence in any appropriate manner. For example, the initiating AP may transmit a request, a confirmation, a cross-BSS CSI report, etc. That is, the cross-BSS CSI reporting sequence does not necessarily have to begin with a request for a cross-BSS CSI report or the transmission of a cross-BSS CSI report. Since the cross-BSS CSI reporting sequence can be initiated in various ways, an appropriate communication mode may be applied. An exemplary cross-BSS CSI reporting sequence is described below with reference to FIGS. 3 through 9.

[0043] Indications as to whether an AP, such as AP2, has received a cross-BSS CSI report may be provided in various ways. For example, a frame included in a transmission from AP2 to AP1 may contain one or more bits indicating that AP2 possesses the same cross-BSS CSI report. Additionally, or alternatively, AP2 may transmit one or more bits indicating that it has not received a cross-BSS CSI report. Such indications may be transmitted through any appropriate layer of the communication protocol. For example, such notifications may be transmitted through the Media Access Control (MAC) layer defined by Wi-Fi standards.

[0044] The frame or packet used to transmit an indication that AP2 has received or possesses a cross-BSS CSI report may be a previously defined or newly defined one. For example, the frame or packet may include bits or fields that can be used or reallocated to indicate that AP2 possesses or has received a cross-BSS CSI report. Various embodiments of such indication are described below.

[0045] FIG. 3 is a transmission diagram (300) for cross-BSS CSI status request and reporting from an initiation AP according to one embodiment.

[0046] Referring to FIG. 3, the transmission diagram (300) includes a cross-BSS CSI report sequence (310). The cross-BSS CSI report sequence (310) includes transmission between AP1 and AP2. In the cross-BSS CSI report sequence (310), AP1 transmits a cross-BSS CSI status request to AP2. AP2 responds with an acknowledgment of the cross-BSS CSI request. Subsequently, AP1 transmits a cross-BSS CSI report to AP2, and AP2 responds with a second cross-BSS CSI report acknowledgment. Thus, according to the cross-BSS CSI report sequence (310) of FIG. 3, AP1 can check the status of AP2 and, if AP2 indicates that it did not receive a cross-BSS CSI report in response to the status request, can optionally transmit the cross-BSS CSI report to AP2. The transmission sequence of the cross-BSS CSI report sequence (310) can operate in any communication mode, including overhearing and backhaul / wireless transmission. However, depending on the communication mode, additional airtime may be required for AP1 to check the status of AP2 and transmit cross-BSS CSI feedback to AP2.

[0047] FIG. 4 is a transmission diagram (400) for a cross BSS CSI report from an initiation AP according to one embodiment.

[0048] Referring to FIG. 4, the transmission diagram (400) includes a cross-BSS CSI report sequence (410). The cross-BSS CSI report sequence (410) begins with a cross-BSS CSI report being transmitted from AP1 to AP2. In response, AP2 transmits a cross-BSS CSI ACK to AP1. Accordingly, both AP1 and AP2 come to possess the cross-BSS CSI report. Additionally, AP1 can know that AP2 possesses the cross-BSS CSI report. That is, in the transmission diagram (400), AP1 directly transmits the cross-BSS CSI report to AP2 without requesting acknowledgment from AP2. Accordingly, additional airtime required for the request and acknowledgment of the response is not used. The cross-BSS CSI report sequence (410) can be applied in all cases, including overhearing and backhaul / wireless transmission methods.

[0049] FIG. 5 is a transmission diagram (500) for bidirectional cross-BSS CSI reporting, request, or confirmation according to one embodiment.

[0050] Referring to FIG. 5, the transmission diagram (500) includes a cross-BSS CSI report sequence (510). The cross-BSS CSI report sequence (510) illustrated in FIG. 5 may be a transmission from an initiating AP to a responding AP. The cross-BSS CSI report sequence (510) includes a cross-BSS CSI report, request, or ACK initiated by AP1. Additionally, the cross-BSS CSI report sequence (510) includes a cross-BSS CSI report, request, or ACK subsequently transmitted by AP2.

[0051] FIG. 6 is a transmission diagram (600) of an embodiment for a bidirectional cross-BSS CSI report, request, or confirmation described with reference to FIG. 5.

[0052] Referring to FIG. 6, similar to FIG. 5, the transmission diagram (600) includes a cross-BSS CSI report sequence (610). The cross-BSS CSI report sequence (610) illustrated in FIG. 6 may be a transmission from a responding AP to an initiating AP. The cross-BSS CSI report sequence (610) includes a cross-BSS CSI report, a cross-BSS CSI request, or an ACK initiated by AP2. Additionally, the cross-BSS CSI report sequence (610) includes a cross-BSS CSI report, a request, or an ACK subsequently transmitted by AP1.

[0053] The cross-BSS CSI report sequence (510, 610) may include a cross-BSS CSI failure check. A cross-BSS CSI reception failure check may indicate to AP1 that AP2 did not receive a cross-BSS CSI report from STA1. If cross-BSS CSI reception fails, a retransmission from NDPA may occur. Other options may also apply in the event of a cross-BSS CSI reception failure. For example, AP1 and / or AP2 may simply continue Co-BF or Coordinated Space Reuse (Co-SR), a cross-BSS CSI report retransmission may occur, sounding / Co-BF may be restarted, Coordinated Time Division Multiple Access (Co-TDMA) may be performed, or AP1 or AP2 may take charge of uncoordinated transmission.

[0054] Referring to FIGS. 5 and 6, the cross-BSS CSI reporting sequence (510, 610) includes a transmission sequence in which AP1 and AP2 check their respective AP status and / or transmit the cross-BSS CSI report bidirectionally and / or sequentially after / co-sounding and before Co-BF transmission.

[0055] FIG. 7 is a transmission diagram (700) for a cross BSS CSI status request from an initiation AP according to one embodiment.

[0056] Referring to FIG. 7, the transmission diagram (700) includes a cross-BSS CSI report sequence (710). The cross-BSS CSI report sequence (710) may operate even if AP2 has already received a CSI report transmitted from STA1 via backhaul or AP1, or if AP2 has already received a cross-BSS CSI report. If AP2 has already received a cross-BSS CSI report, a small overhead may occur. The cross-BSS CSI report sequence (710) may provide additional time and signals to allow AP2 to prepare the cross-BSS CSI report.

[0057] FIG. 8 is a transmission diagram (800) for transmitting a cross-BSS CSI report from an initiation AP including retransmission according to one embodiment.

[0058] Referring to FIG. 8, the transmission diagram (800) includes a cross-BSS CSI report sequence (810). The cross-BSS CSI report sequence (810) consists of a cross-BSS CSI request transmitted by AP2 to AP1, a cross-BSS CSI report transmitted by AP1 to AP2, and a cross-BSS CSI acknowledgment (ACK) transmitted by AP2 to AP1. The cross-BSS CSI report sequence (810) can be applied in all communication modes, including overhearing and backhaul / wireless transmission.

[0059] FIG. 9 is a transmission diagram (900) for cross-BSS CSI verification from a response AP according to one embodiment.

[0060] Referring to FIG. 9, the transmission diagram (900) includes a cross-BSS CSI report sequence (910). The cross-BSS CSI report sequence (910) consists of a cross-BSS CSI acknowledgment (ACK). That is, the cross-BSS CSI report sequence (910) consists of a single transmission transmitted by AP2 to AP1 to acknowledge the receipt or retention of the cross-BSS CSI report. The cross-BSS CSI acknowledgment (ACK) can be applied in all cases, such as overhearing, backhaul / wireless transmission.

[0061] FIG. 10 is a transmission diagram (1000) for a cross-BSS CSI request of a response AP according to one embodiment.

[0062] Referring to FIG. 10, the transmission diagram (1000) includes a cross-BSS CSI report sequence (1010). The cross-BSS CSI report sequence (1010) includes a cross-BSS CSI request that AP2 transmits to AP1. AP1 responds by transmitting a cross-BSS CSI report. AP2 responds with a cross-BSS CSI acknowledgment (ACK). The cross-BSS CSI report sequence (1010) may be applicable in all cases involving overhearing and transmission via backhaul or wireless transmission. The cross-BSS CSI request may be combined with a cross-BSS CSI acknowledgment or a beamforming report pull (ACK / BFRP). AP2 may require information from AP1 and STA1 regarding whether the cross-BSS CSI report is ready.

[0063] FIG. 11 illustrates a method (1100) for performing Co-BF in OBSS according to one embodiment.

[0064] Referring to FIG. 11, the method (1100) can detect an OBSS between AP1 and AP2 by AP1 in step (1110). In step (1120), the method (1100) can transmit an indication by AP1 indicating whether AP1 has received a cross-BSS CSI report. In step (1130), the method (1100) can coordinate (cooperate) with AP2 to perform a Co-BF procedure based on the cross-BSS CSI report by AP1.

[0065] The method (1100) may further include the step of transmitting the indication by transmitting either a reception indication that the first AP has received the cross-BSS channel status information (CSI) report or a reception failure indication that the first AP has not received the cross-BSS CSI report. Additionally or alternatively, the method may further include the step of receiving an indication from the second AP regarding whether the first AP has received the cross-BSS CSI report. The method may further include the step of indicating the reception of the cross-BSS CSI report by the first AP transmitting an indication of reception of the cross-BSS CSI report to the second AP via one of wireless transmission, overhearing, or transmission via a wired backhaul connection.

[0066] The method (1100) may further include the step of indicating that the first AP has received a cross-BSS CSI report by transmitting a frame containing one or more indication bits by the first AP. The frame containing one or more indication bits is used in a protocol unrelated to the indication of whether the first AP has received a cross-BSS CSI report. Additionally or alternatively, the frame may include one or more indication bits transmitted at the Media Access Control (MAC) layer of a transmission received by the second AP. The method (1100) may further include the step of transmitting an indication of whether the first AP has received a cross-BSS CSI report in response to the first AP receiving a request from the second AP.

[0067] The method (1100) may further include the step of initiating a transmission by the first AP of an indication of whether the first AP has received a cross-BSS CSI report, either the second AP or the first AP. The method (1100) may additionally include the step of transmitting a cross-BSS CSI report to the second AP by the second AP and receiving a cross-BSS CSI report by the first AP.

[0068] There may be various considerations regarding the MAC layer. For example, since a Co-BF AP may initiate a Co-BF procedure / transmission only when the transmission opportunity (TXOP) is longer than a TXOP length threshold, such as a threshold of a predetermined length, the Co-BF gain may be sufficient to justify MAC overhead (e.g., ICF / ICR, NDP sounding, same BSS / cross BSS CSI feedback, block acknowledgment request / block acknowledgment (BAR / BA)). The TXOP length threshold can be calculated according to various scenarios.

[0069] Additionally, Co-BF non-AP STAs may need to be available for parameters negotiated during the Co-BF TXOP (e.g., channel, bandwidth, time window). This helps reduce potential errors, retransmissions, interruptions, and / or switching operations that may occur during the Co-BF TXOP. Some power management or related functions, such as Dynamic Power Saving (DPS), Duplex Operation (DUO), Null Frame Power Saving, Control Check (NPCA), Dynamic STA Operation (DSO), PM=1, etc., may be restricted or disabled for non-AP STAs participating in Co-BF. As some possible exceptions, certain Co-BF non-AP STAs may enter a power saving or disabled mode depending on the Co-BF type (sequential / co-sounding) and scheduling within the Co-BF TXOP.

[0070] Aspects of some embodiments may enable cross-BSS CSI feedback from Co-BF. To balance various system requirements such as performance, overhead, complexity, and flexibility, some embodiments may include cross-BSS CSI status requests / reports initiated from an initiating AP or bidirectional cross-BSS CSI reports / requests / ACKs initiated from an initiating / responding AP.

[0071] FIG. 12 illustrates an exemplary block diagram of an electronic device in which the system and method described herein may be implemented according to one embodiment.

[0072] Referring to FIG. 12, an electronic device (1201) in a network environment (1200) can communicate with an electronic device (1202) through a first network (1298) (e.g., a short-range wireless communication network) or with an electronic device (1204) or a server (1208) through a second network (1299) (e.g., a long-range wireless communication network). The electronic device (1201) can communicate with the electronic device (1204) through the server (1208). The electronic device (1201) includes a processor (1220), memory (1230), input device (1250), sound output device (1255), display device (1260), audio module (1270), sensor module (1276), interface (1277), haptic module (1279), camera module (1280), power management module (1288), battery (1289), communication module (1290), subscriber identification module (SIM) card (1296), or antenna module (1297). In one embodiment, at least one of the components (e.g., display device (1260) or camera module (1280)) may be omitted from the electronic device (1201), or one or more other components may be added to the electronic device (1201). Some of the components may be implemented as a single integrated circuit (IC). For example, a sensor module (1276) (e.g., a fingerprint sensor, an iris sensor, or an ambient light sensor) can be embedded in a display device (1260) (e.g., a display).

[0073] The processor (1220) can control at least one other component (e.g., a hardware or software component) of the electronic device (1201) connected to the processor (1220) by executing software (e.g., a program (1240)) and can perform various data processing or operations. For example, the processor (1220) can transmit an indication that a cross-BSS CSI report has been received by AP1. Thus, the processor (1220) can execute a program for Co-BF using the same cross-BSS CSI report as another AP.

[0074] As at least part of data processing or computation, the processor (1220) may load commands or data received from other components of volatile memory (1232) (e.g., sensor module (1276) or communication module (1290)), process commands or data stored in volatile memory (1232), and store resulting data in non-volatile memory (1234). The processor (1220) may include a main processor (1221) (e.g., central processing unit (CPU) or application processor (AP)), and an auxiliary processor (1223) (e.g., graphics processing unit (GPU), image signal processor (ISP), sensor hub processor, or communication processor (CP)) that may operate independently or together with the main processor (1221). Additionally or alternatively, the auxiliary processor (1223) may be configured to consume less power than the main processor (1221) or to perform specific capabilities. The auxiliary processor (1223) may be implemented separately from the main processor (1221) or as part of it.

[0075] The auxiliary processor (1223) can control at least some of the functions or states associated with at least one component of the electronic device (1201) (e.g., a display device (1260), a sensor module (1276), or a communication module (1290)) in contrast to the main processor (1221) while the main processor (1221) is in an inactive (e.g., sleep) state, or together with the main processor (1221) while the main processor (1221) is in an active state (e.g., running an application). The auxiliary processor (1223) (e.g., an image signal processor or a communication processor) may be implemented as part of another component functionally associated with the auxiliary processor (1223) (e.g., a camera module (1280) or a communication module (1290)).

[0076] The memory (1230) may store various data used by at least one component of the electronic device (1201) (e.g., a processor (1220) or a sensor module (1276)). The various data may include, for example, input data or output data for software (e.g., a program (1240)) and related instructions. The memory (1230) may include volatile memory (1232) or non-volatile memory (1234). The non-volatile memory (1234) may include internal memory (1236) and / or external memory (1238).

[0077] The program (1240) may be stored in memory (1230) as software and may include, for example, an operating system (OS) (1242), middleware (1244), or an application (1246).

[0078] The input device (1250) can receive commands or data to be used by another component of the electronic device (1201) (e.g., processor (1220)) from outside the electronic device (1201) (e.g., user). The input device (1250) may include, for example, a microphone, a mouse, or a keyboard.

[0079] The sound output device (1255) can output a sound signal to the outside of the electronic device (1201). The sound output device (1255) may include, for example, a speaker or a receiver. The speaker may be used for general purposes such as multimedia playback or recording, and the receiver may be used to receive incoming calls. The receiver may be separate from the speaker or implemented as part of the speaker.

[0080] The display device (1260) can provide visual information to an external party (e.g., a user) of the electronic device (1201). The display device (1260) may control the corresponding display, holographic device, and projector, for example, by including a display, holographic device, or projector and a control circuit. The display device (1260) may include a touch circuit configured to detect a touch, or a sensor circuit (e.g., a pressure sensor) configured to measure the intensity of a force generated by a touch.

[0081] The audio module (1270) can convert sound into an electrical signal or vice versa. The audio module (1270) can acquire sound through an input device (1250) or output sound through headphones of an external electronic device (1202) that is directly (e.g., wired) or wirelessly connected to an audio output device (1255) or an electronic device (1201).

[0082] The sensor module (1276) can detect the operating state of the electronic device (1201) (e.g., power or temperature) or the environmental state outside the electronic device (1201) (e.g., user state), and can then generate an electrical signal or data value corresponding to the detected state. The sensor module (1276) may include, for example, a gesture sensor, a gyroscope sensor, an atmospheric pressure sensor, a magnetic sensor, an accelerometer sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

[0083] The interface (1277) may support one or more specified protocols to be used for the electronic device (1201) to be connected directly (e.g., by wire) or wirelessly to an external electronic device (1202). The interface (1277) may include, for example, a High Resolution Multimedia Interface (HDMI), a Universal Serial Bus (USB) interface, a Secure Digital (SD) card interface, or an audio interface.

[0084] The connection terminal (1278) may include a connector that allows the electronic device (1201) to be physically connected to an external electronic device (1202). The connection terminal (1278) may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (for example, a headphone connector).

[0085] The haptic module (1279) can convert an electrical signal into a mechanical stimulus (e.g., vibration or movement) or an electrical stimulus that can be perceived by the user through touch or kinesthetic sensation. The haptic module (1279) may include, for example, a motor, a piezoelectric element, or an electric stimulator.

[0086] The camera module (1280) can capture still images or video. The camera module (1280) may include one or more lenses, image sensors, ISPs, or flashes. The power management module (1288) can manage power supplied to the electronic device (1201). The power management module (1288) may be implemented, for example, as at least part of a power management integrated circuit (PMIC).

[0087] The battery (1289) can supply power to at least one component of the electronic device (1201). The battery (1289) may include, for example, a non-rechargeable primary battery, a rechargeable secondary battery, or a fuel cell.

[0088] The communication module (1290) may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between an electronic device (1201) and an external electronic device (e.g., electronic device (1202), electronic device (1204), or server (1208)) and performing communication through the established communication channel. The communication module (1290) may include one or more CPs capable of operating independently of a processor (1220) (e.g., AP) and may support direct (e.g., wired) communication or wireless communication. The communication module (1290) may include a wireless communication module (1292) (e.g., cellular communication module, short-range wireless communication module, or Global Satellite Navigation System (GNSS) communication module) or a wired communication module (1294) (e.g., local area network (LAN) communication module or power line communication (PLC) module). The corresponding module among these communication modules is a first network (1298) (e.g., Bluetooth). ®It can communicate with an external electronic device via a short-range communication network such as Wireless Fidelity (Wi-Fi) Direct or Infrared Data Association (IrDA) standards) or a second network (1299) (e.g., a long-range communication network such as a cellular network, the Internet, or a computer network (e.g., a LAN or a Wide Area Network (WAN)). Bluetooth ® Bluetooth is a registered trademark of Bluetooth SIG, Inc., Kirkland, Washington. These various types of communication modules may be implemented as a single component (e.g., a single IC) or as multiple separate components (e.g., multiple ICs). The wireless communication module (1292) can identify and authenticate an electronic device (1201) in a communication network, such as a first network (1298) or a second network (1299), by using subscriber information (e.g., International Mobile Subscriber Identifier (IMSI)) stored in a subscriber identification module (1296).

[0089] The antenna module (1297) can transmit or receive signals or power to and from the outside of the electronic device (1201) (e.g., an external electronic device). The antenna module (1297) may include one or more antennas, and from this, at least one antenna suitable for a communication method used in a communication network such as a first network (1298) or a second network (1299) may be selected by, for example, a communication module (1290) (e.g., a wireless communication module (1292)). Then, signals or power can be transmitted or received between the communication module (1290) and the external electronic device through the selected at least one antenna.

[0090] Commands or data may be transmitted between the electronic device (1201) and the external electronic device (1204) via a server (1208) combined with the second network (1299). Each electronic device (1202, 1204) may be of the same type as the electronic device (1201) or a different type of device. All or part of the operation to be performed on the electronic device (1201) may be performed on one or more of the external electronic devices (1202, 1204). For example, if the electronic device (1201) needs to perform a function or service automatically or at the request of a user or another device, the electronic device (1201) may request one or more external electronic devices to perform at least part of the function or service instead of performing the function or service, or in addition thereto. One or more external electronic devices that receive the request may perform at least part of the requested function or service, or additional functions or additional services related to the request, and transmit the result of the performance to the electronic device (1201). The electronic device (1201) may provide a result, with or without further processing of the result, as at least part of the response to the request. For this purpose, for example, cloud computing, distributed computing, or client-server computing technology may be used.

[0091] FIG. 13 illustrates a system (1300) comprising an AP (1310), another AP (1320), and a STA (1330). The AP (1310), another AP (1320), and the STA (1330) may communicate with each other depending on whether the STA (1330) is associated with the AP (1310). That is, the solid arrows between the AP (1310), the other AP (1320), and the STA (1330) do not necessarily illustrate an association between the STA (1330) and one of the AP (1310) and the other AP (1320).

[0092] Referring to FIG. 13, the STA (1330) may include a wireless circuit (1332) and a processing circuit (or processing means) (1334), and the processing circuit (1334) may perform various methods disclosed herein, such as the methods illustrated in FIG. 3 through 11, for example. For example, if the STA (1330) is associated with an AP (1310), the processing circuit (1334) may receive a transmission from the AP (1310) via the wireless circuit (1332) and transmit a signal to the AP (1310) via the wireless circuit (1332). Additionally, or alternatively, the AP (1310) and another AP (1320) may include a transceiver (1312, 1322) and a processing circuit (1314, 1324) configured to perform all or part of the methods described in relation to FIG. 3 through 11.

[0093] A signal transmitted by one of the processing circuits (1314, 1324) may include an indication of a cross-BSS CSI status transmitted between AP (1310) and another AP (1320). For example, STA (1330) may not be associated with AP (1310), and accordingly, AP (1310) may overhear communication between STA (1330) and another AP (1320) associated with STA (1330). Accordingly, the other AP (1320) may determine, for example, from STA (1330) that AP (1310) has received a cross-BSS CSI report.

[0094] Conversely, if the STA (1330) is associated with the AP (1310), the AP (1310) may send a frame, such as an NDPA, to the STA (1330) to initiate a CSI measurement. The CSI measurement may be a cross-BSS CSI measurement between the STA (1330) and another AP (1320). The AP (1310) may also send a frame (e.g., BFRP) to the STA (1330) to request a CSI report. The STA (1330) may send a CSI report to the AP (1310) in response to the request. Another AP (1320) may overhear the CSI report being sent from the STA (1330) to the AP (1310). Additionally or alternatively, the AP (1310) may transmit a CSI report to another AP (1320), for example, via a wired or backhaul connection with another AP (1320). The CSI report may include a cross-BSS CSI report. The other AP (1320) may transmit an indication to the AP (1310) that the CSI report has been received.

[0095] Embodiments of the subject matter and operation described herein may be implemented in digital electronic circuits, or in computer software, firmware, or hardware, including structures disclosed herein and structural equivalents thereof, or combinations of one or more of these. Embodiments of the subject matter described herein may be implemented as one or more computer programs, namely, as one or more modules of computer program instructions encoded in a computer storage medium to be executed by a data processing device or to control the operation of a data processing device. Alternatively or additionally, program instructions may be encoded in artificially generated radio signals, e.g., mechanically generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiver device for execution by the data processing device. The computer storage medium may be a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof, or may be included therein. Additionally, although the computer storage medium is not a radio signal, the computer storage medium may be a source or destination of computer program instructions encoded in an artificially generated radio signal. A computer storage medium may be one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices) or may be included therein. Additionally, the operations described herein may be implemented as operations performed by a data processing device on data stored in one or more computer-readable storage devices or received from other sources.

[0096] While this specification may contain many specific implementation details, such implementation details should not be interpreted as a limitation on the scope of the claimed subject matter, but rather as a description of features specific to specific embodiments. Specific features described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although a function may be described as operating in a specific combination and may be initially claimed as such, one or more features from the claimed combination may, in some cases, be excluded from this combination, and the claimed combination may relate to a sub-combination or a variation of a sub-combination.

[0097] Similarly, although operations are depicted in a specific order in the drawings, this should not be understood as requiring that these operations be performed in the specific order depicted or in a sequential order to achieve desirable results, or that all illustrated operations be performed. In certain situations, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems may generally be integrated together into a single software product or packaged into multiple software products.

[0098] Accordingly, specific embodiments of the subject matter have been described herein. Other embodiments are included in the following claims. In some cases, the desired results may be obtained even if the measures specified in the claims are performed in a different order. Additionally, the process illustrated in the accompanying drawings does not necessarily require the specific order or sequential order shown to obtain the desired results. In certain implementations, multitasking and parallel processing may be preferred.

[0099] As recognized by those skilled in the art, the innovative concepts described herein may be modified and changed across a wide range of applications. Accordingly, the scope of the claimed subject matter should not be limited to the specific exemplary teachings set forth above, but should be defined by the following claims.

Claims

Claim 1 A method for performing coordinated beamforming (Co-BF), the method comprising: detecting an overlapping basic service set (BSS) between the first AP and the second AP by means of a first access point (AP); transmitting an indication by means of the first AP whether the first AP has received a cross-BSS channel state information (CSI) report; and coordinating with the second AP by means of the first AP to perform a coordinated beamforming (Co-BF) procedure based on the cross-BSS CSI report. Claim 2 A method according to claim 1, further comprising the step of transmitting the indication by transmitting one of a reception indication indicating that the first AP has received the cross-BSS channel status information (CSI) report and a reception failure indication indicating that the first AP has not received the cross-BSS CSI report. Claim 3 A method according to claim 1, further comprising the step of receiving, by the second AP, the indication of whether the first AP has received the cross BSS CSI report. Claim 4 A method according to claim 1, further comprising the step of indicating the reception of the cross-BSS CSI report by the first AP transmitting the indication of the reception of the cross-BSS CSI report to the second AP in one of the methods of wireless transmission, overhearing, or transmission via a wired backhaul connection. Claim 5 A method according to claim 1, further comprising the step of the first AP indicating the reception of the cross BSS CSI report by transmitting a frame containing one or more indication bits by the first AP. Claim 6 In paragraph 5, the frame containing one or more indication bits is used in a protocol unrelated to the indication of whether the first AP has received the cross BSS CSI report. Claim 7 In paragraph 5, the method wherein the frame containing one or more of the above-mentioned indicator bits is transmitted at the Media Access Control (MAC) layer of the transmission received by the second AP. Claim 8 A method according to claim 1, further comprising the step of transmitting the indication of whether the first AP has received the cross BSS CSI report in response to the first AP receiving a request from the second AP. Claim 9 A method according to claim 1, further comprising the step of one of the second AP and the first AP initiating the transmission by the first AP of the indication of whether the first AP has received the cross BSS CSI report. Claim 10 A method according to claim 1, further comprising the step of transmitting the cross BSS CSI report to the first AP by the second AP and receiving the cross BSS CSI report by the first AP. Claim 11 A system comprising a first AP having a second access point (AP) and an overlapping basic service set (BSS), wherein the first AP is configured to transmit an indication of whether the first AP has received a cross-BSS channel status information (CSI) report from the second AP, and wherein the first AP is configured to coordinate with the second AP to perform a cooperative beamforming (Co-BF) procedure based on the cross-BSS CSI report. Claim 12 A system according to claim 11, wherein the first AP is further configured to transmit the indication by transmitting one of a reception indication indicating that the first AP has received the cross BSS CSI report and a reception failure indication indicating that the first AP has not received the cross BSS CSI report. Claim 13 In paragraph 11, the system is further configured such that the second AP receives the indication of whether the first AP has received the cross BSS CSI report. Claim 14 A system according to claim 11, wherein the first AP is further configured to indicate the reception of the cross-BSS CSI report by transmitting the indication of the reception of the cross-BSS CSI report to the second AP in one of the ways of wireless transmission, overhearing, or transmission via a wired backhaul connection. Claim 15 In paragraph 11, the system is further configured such that the first AP indicates the reception of the cross BSS CSI report by transmitting a frame containing one or more indication bits. Claim 16 In paragraph 15, the frame containing one or more indication bits is used in a system that is not related to the indication of whether the first AP has received the cross-BSS CSI report. Claim 17 In paragraph 15, the frame containing one or more of the above-mentioned indicator bits is transmitted at the Media Access Control (MAC) layer of the transmission received by the second AP, in a system. Claim 18 In paragraph 11, the system is further configured such that the first AP indicates receipt of the cross BSS CSI report in response to the first AP receiving a request from the second AP. Claim 19 A system according to claim 11, wherein one of the second AP and the first AP is further configured to initiate the transmission of the indication of whether the first AP has received the cross BSS CSI report. Claim 20 A system according to claim 11, wherein the second AP is further configured to transmit the cross-BSS CSI report to the first AP, and the first AP is configured to receive the cross-BSS CSI report.

Images