WO2023178523A1

WO2023178523A1 - Device, method and medium for mesh network

Info

Publication number: WO2023178523A1
Application number: PCT/CN2022/082316
Authority: WO
Inventors: Yan Meng; Tao Tao; Jianguo Liu; Zhijie Yang; Wenjian Wang
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy
Priority date: 2022-03-22
Filing date: 2022-03-22
Publication date: 2023-09-28

Abstract

Embodiments of the present disclosure relate to device, method, apparatus and computer readable storage medium in a VBSS based mesh network. The method implemented in a first device comprises receiving a probe request from a terminal device; upon receipt of the probe request, based on its Received Signal Strength Indication (RSSI) value being higher than a threshold, sending a probe response to the terminal device to send an authentication request; substantially in parallel with sending the probe response, receiving a token request from one or more second devices; selecting a serving device from the one or more second devices; and sending a token distribution indication to the one or more second devices indicating that the serving device has the token and is permitted to communicate with the terminal device. In this way, latency can be greatly reduced in the STA access procedure.

Description

DEVICE, METHOD AND MEDIUM FOR MESH NETWORK

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to device, method and computer-readable storage medium for Virtual Basic Service Set (Virtualized BSS, or VBSS) mesh network.

BACKGROUND

Wi-Fi network is widely used in various places like home and office buildings, and Wi-Fi network coverage and performance have won more attention recently. To address this need, several proprietary, multi-AP (Access Point) solutions have emerged on the market. In order to provide an industry specification and certification program for Wi-Fi coverage that utilizes multiple APs, Wi-Fi CERTIFIED EasyMeshTM R1 (i.e., Multi-AP R1) was launched in June 2018, and Wi-Fi CERTIFIED EasyMeshTM R2 (i.e., Multi-AP R2) was launched in December 2019 as part of WFA (Wi-Fi Alliance) 2019-December Feature Release. Wi-Fi CERTIFIED EasyMeshTM R3 was launched in February 2021 as part of WFA 2020-December Feature Release. Wi-Fi certification benefits both consumers and service providers through interoperability of products from different vendors.

The Wi-Fi EasyMesh R5 program will focus on QoS (Quality of Service) Management Supported, Virtualized BSS for Multi-AP Coordination and Station Access Control. It will provide a unique value proposition of continuing the development of interoperable Multi-AP solutions to deliver a high-quality user experience for in-home Wi-Fi, especially when a user (or service provider) wants his device to always be connected to the best AP/band without incurring the handoff cost of re-association or re-negotiation of security.

A virtualized BSS allows the BSS context to be moved from one AP to another AP, and from one band/channel to another band/channel, using make-before-break (MBB) technology to move the device without the device needing to re-associate or re-negotiate security. By continuously monitoring the device connection (signal quality between the device and the available APs) , the device is moved to the best radio and band on the best AP, without reduction in throughput.

In the VBSS mesh network, all AP nodes share the same SSID (Service Set Identifier) . The collaboration among these AP nodes ensures that the station (STA, also referred to as “terminal device” ) in this network can seamlessly roam from one AP to another, which dispense with the need to re-establish a connection, thus improving the security of the user data and significantly reducing the delay, with the latter merit making the seamless roaming of AR/VR featuring large data volume possible. In addition, since all AP nodes share the same SSID in the VBSS mesh network, the STA perceives all APs in the network as one single AP, so no adjustment is needed at the STA end, and this is compatible with most of the STAs in the market.

The VBSS mesh network has the following features. First, a VBSS mesh network contains two or more AP nodes. Second, AP nodes in the VBSS mesh network communicate with each other via backhaul based on wireless link, and among all the AP nodes, the root AP can communicate with the Ethernet via an Ethernet link. Third, the fronthaul of AP nodes share the same SSID, BSSID, BSS Color, AID and Beacon frame timestamp. In other words, all AP nodes in the VBSS mesh network are accessible to the terminal device via a same identifier. Fourth, when the STA is connected to or reconnected to a VBSS mesh network, all AP nodes can acquire and update the GTK, PTK and other security context needed to communicate with the STA. Furthermore, there is only one token in a VBSS mesh network, and only the AP node which has the token can communicate with a certain STA: only AP (s) with the token can communicate with the STA, while other APs can receive packets from the STA but cannot reply with ACK (Acknowledgment) or CTS frame.

SUMMARY

In general, example embodiments of the present disclosure provide a solution of low latency station access mechanism for VBSS mesh network.

In a first aspect, there is provided a first device. The first device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first device at least to receive a probe request from a terminal device; upon receipt of the probe request, send a probe response to the terminal device to send an authentication request; substantially in parallel with sending the probe response, receive a token request from one or more second devices; select a serving device from the one or more second devices; and send a token distribution indication to the one or more second devices indicating that the serving device has the token and is permitted to communicate with the terminal device .

In a second aspect, there is provided a second device. The second device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the second device at least to receive a probe request from a terminal device; and upon receipt of the probe request, send a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has the token and is permitted to communicate with the terminal device.

In a third aspect, there is provided a mesh network. The mesh network comprises a first device according to the first aspect and one or more second devices according to the second aspect.

In a fourth aspect, there is provided a method implemented in a first device according to the first aspect. The method comprises receiving a probe request from a terminal device; upon receipt of the probe request, sending a probe response to the terminal device to send an authentication request; substantially in parallel with sending the probe response, receiving a token request from one or more second devices; selecting a serving device from the one or more second devices; and sending a token distribution indication to the one or more second devices indicating that the serving device has the token and is permitted to communicate with the terminal device.

In a fifth aspect, there is provided a method implemented in a second device according to the second aspect. The method comprises receiving a probe request from a terminal device; and upon receipt of the probe request, sending a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has the token and is permitted to communicate with the terminal device.

In a sixth aspect, there is provided an apparatus implemented in a first device according to the first aspect. The apparatus comprises means for receiving a probe request from a terminal device; means for sending, upon receipt of the probe request from the terminal device, a probe response to the terminal device to send an authentication request; means for receiving, substantially in parallel with sending the probe response, a token request from one or more second devices; means for selecting a serving device from the one or more second devices; and means for sending a token distribution indication to the one or more second devices indicating that the serving device has the token and is permitted to communicate with the terminal device.

In a seventh aspect, there is provided an apparatus implemented in a second device according to the second aspect. The apparatus comprises means for receiving a probe request from a terminal device; and means for sending, upon receipt of the probe request, a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has the token and is permitted to communicate with the terminal device.

In an eighth aspect, there is provided computer-readable storage medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the least one processor to perform the method to any of the third to fourth aspects.

Other features and advantages of the embodiments of the present disclosure will also be apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are presented in the sense of examples and their advantages are explained in greater detail below, with reference to the accompanying drawings, where

FIG. 1 illustrates an example environment in which example embodiments of the present disclosure can be implemented;

FIG. 2 illustrates a signaling chart 200 demonstrating an existing STA access procedure in a VBSS mesh network;

FIG. 3 illustrates a signaling chart 300 demonstrating an example of STA access procedure in a VBSS mesh network according to some embodiments of the present disclosure;

FIG. 4 illustrates a signaling chart 400 demonstrating another example of STA access procedure in a VBSS mesh network according to some embodiments of the present disclosure;

FIG. 5 illustrates a signaling chart 500 demonstrating an example of serving AP selection procedure in a VBSS mesh network according to some embodiments of the present disclosure;

FIG. 6 illustrates a signaling chart 600 demonstrating an example of probe response procedure in a VBSS mesh network according to some embodiments of the present disclosure;

FIG. 7 illustrates a signaling chart 700 demonstrating an example of authentication procedure in a VBSS mesh network according to some embodiments of the present disclosure;

FIG. 8 illustrates a flowchart 800 of an example method executed in the root AP in a VBSS based mesh network according to some example embodiments of the present disclosure;

FIG. 9 illustrates a flowchart 900 of an example method executed in the extended AP in a VBSS based mesh network according to some example embodiments of the present disclosure;

FIG. 10 illustrates a simplified block diagram 1000 of a root AP or extended AP that is suitable for implementing example embodiments of the present disclosure; and

Fig. 11 illustrates a block diagram 1100 of an example computer-readable storage medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessarily that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish functionalities of various elements. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and/or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term “circuitry” also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Wi-Fi, fifth generation (5G) systems, Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) new radio (NR) communication protocols, Wi-Fi1 -Wi-Fi7 and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Just for simplicity of description, Wi-Fi will be taken as an example in the description below. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR Next Generation NodeB (gNB) , a Remote Radio Unit (RRU) , a radio head (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. A RAN split architecture comprises a gNB-CU (Centralized unit, hosting RRC, SDAP and PDCP) controlling a plurality of gNB-DUs (Distributed unit, hosting RLC, MAC and PHY) . A relay node may correspond to DU part of the gNB node.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , a Station (STA) or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. The terminal device may also correspond to Mobile Termination (MT) part of the integrated access and backhaul (IAB) node (a.k.a. a relay node) . In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” , “STA” and “UE” may be used interchangeably.

Although functionalities described herein can be performed, in various example embodiments, in a fixed and/or a wireless network node, in other example embodiments, functionalities may be implemented in a user equipment (such as a cell phone or tablet computer or laptop computer or desktop computer or mobile IoT device or fixed IoT device) . This user equipment can, for example, be furnished with corresponding capabilities as described in connection with the fixed and/or the wireless network node (s) , as appropriate. The user equipment may be the user equipment and/or a control device, such as a chipset or processor, configured to control the user equipment when installed therein. Examples of such functionalities include the bootstrapping server function and/or the home subscriber server, which may be implemented in the user equipment by providing the user equipment with software configured to cause the user equipment to perform from the point of view of these functions/nodes.

FIG. 1 shows an example environment in which embodiments of the present disclosure can be implemented. As illustrated in FIG. 1, the environment comprises a communication network 100 encompassed by the dotted rectangle. For example, the communication network 100 is a VBSS mesh network and comprises multiple APs 110-1, 110-2 and 110-3. In the communication network 100, the AP 110-1 may be considered as a root AP (hereinafter also referred to as a first device 110-1) and the APs 110-2 and 110-3 may be considered as extended APs (hereinafter also referred to as a second device) . The extended APs 110-2 and 110-3 can communicate with the root AP 110-1 through backhaul link, while the root AP 110-1 accesses the internet through WAN port. A token table is stored in the local database of the root AP 110-1 and is used for the dispense, registration, transfer and recycling of the tokens of the STA 120.

Furthermore, the communication network 100 may also comprise a terminal device 120 (hereinafter may also be referred to as a fourth device 120 or a STA 120. ) All AP nodes (in this example, the root AP 110-1, the extended AP1 110-2 and the extended AP2 110-3) in the VBSS mesh network are accessible to the terminal device, i.e. the STA 120, via a same identifier (for example, the same SSID or BSSID) . When the STA 120 is located in a location where the extended AP1 110-2 provides better communication quality than the extended AP2 110-3 (for example, when the STA 120 is located in the coverage 102 of the extended AP1 110-2) , the STA 120 can communicate with the extended AP1 110-2. When the STA 120 is located in a location where the extended AP2 110-3 provides better communication quality than the extended AP1 110-2 (for example, when the STA 120 moves to the coverage 103 of the extended AP2 110-3) , the STA 120 can communicate with the extended AP2 110-3. It is to be understood that the number of APs and terminal devices shown in FIG. 1 is given for the purpose of illustration without suggesting any limitations. The communication network 100 may include any suitable number of APs and terminal devices.

In current Wi-Fi networks, new ultra-high throughput and stringent low-latency applications are proliferating, such as AR (Augmented Reality) and VR (Virtual Reality) , gaming (e.g., latency lower than 5 ms for online gaming) , telecommuting, online video conference, and cloud computing, etc. The reliability and latency requirements of these use cases vary, but are often in the order of 1 ms –10 ms latency with 99 %-99.9999 %reliability. However, the performance and quality of current Wi-Fi networks are far from satisfying the requirement.

To obtain the internet service, STA 120 needs to connect with the AP which can provide service to it with the best communication quality, whether in the case of initial access, roaming or load balance. In scenarios featuring such large data volume and ultra-low latency application, delay-caused instant sticking during initial access/roaming/load balance and could compromise customer experience. As to the delay in AP switching during roaming, the standard IEEE 802.11r enables an accelerated roaming mechanism, which reduces the delay to 50 ms. However, it still cannot meet the requirements of AR/VR services featuring ultra-low latency.

An initial access mechanism for VBSS mesh network has already been proposed. FIG. 2 illustrates a signaling chart demonstrating an existing STA access procedure in a VBSS mesh network. In step 210, the STA 120 sends a probe request to all APs in the mesh network comprising these APs (step 210) . Upon receiving the probe request, extended APs (in this example, extended AP1 110-2 and extended AP2 110-3) will wait for a token distribution indication from the root AP 110-1. Before the token distribution indication from the root AP 110-1, extended AP1 110-2 and extended AP2 110-3 will do nothing in response to the probe request from STA 120.

Also upon receiving the probe request, a serving AP selection procedure will be started. Specifically, all extended APs may apply for a token from the root AP 110-1 to respond to the STA 120. In other words, all extended APs (in this example, the extended AP1 110-2 and the extended AP2 110-3) may send a token request to the root AP 110-1 to be used to respond to the STA 120; specifically, the extended AP1 110-2 may send a token request to the root AP 110-1 (step 220-1) , and the extended AP2 110-3 may also send a token request to the root AP 110-1 (step 220-2) .

Then, the root AP 110-1, upon receiving the token request from extended AP1 110-2 and extended AP2 110-3, starts a serving AP selection procedure to select a serving AP for the STA 120 in the extended AP1 110-2 and the extended AP2 110-3, and make a serving AP decision (step 230) . The root AP 110-1 may decide a serving AP based on Received Signal Strength Indication (RSSI) or load balance of all extended APs (in this example, extended AP1 110-2 and extended AP2 110-3) . After that decision-making, the root AP 110-1 sends a token distribution indication to only the selected extended AP (in this example, the extended AP1 110-2) . Meanwhile, the selected extended AP1 110-2 receives the token distribution indication (step 240) . The token distribution indication indicates that the selected serving device (in this example, the extended AP1 110-2) has the token and is permitted to communicate with the STA 120.

Upon receiving the token distribution indication from the root AP 110-1, the extended AP1 110-2 becomes aware that it is the serving AP for STA 120 selected by the root AP 110-1, and may send a probe response to the STA 120. At this time, the extended AP2 110-3 will not receive any token distribution indication from the root AP 110-1, and accordingly will not send any probe response.

After receiving the probe response from the serving AP (in this example, the extended AP1 110-2) , the STA 120 may send an authentication request to the serving AP, i.e. the extended AP1 110-2 (step 260) .

After receiving the authentication request from the STA 120 (step 260) , the serving AP, i.e. the extended AP1 110-2 may send an authentication response to the STA 120 (step 270) .

After receiving the authentication response from the serving AP, the STA 120 may then send an association request to the serving AP (step 280) .

After receiving the association request from the STA 120 (step 280) , the serving AP, i.e. the extended AP1 110-2 may send an association response to the STA 120 (step 290) .

As shown in FIG. 2, according to this existing mechanism, the serving AP (i.e., Extended AP1 110-2) must wait for the token distribution indication from the root AP 110-1 and then sends the probe response to the STA 120. Typically, the STA 120 may stay in a channel to receive the probe response for 20 ms after sending the probe request frame, and then move to a next channel to perform a new scan operation. However, the STA 120 may miss the probe response due to the delay caused by the serving AP selection procedure. And then the STA 120 may perform the scan operation again to discover the VBSS network, which may cause a high discovery delay issue. In particular, considering the latency requirements, there exist delay-critical services whose latency requirements are even tighter than the latency introduced by the serving AP selection procedure.

Consequently, the existing STA access procedure that involves the serving AP selection and probe response procedure is not optimized for latency-sensitive applications. In this regard, an enhanced STA access mechanism for VBSS is proposed in order to reduce the latency caused by serving AP selection procedure (including the token application (token request) , serving AP decision and token distribution) .

Embodiments of the present disclosure target on the latency minimization problem in VBSS, especially on procedure optimization for STA access.

FIG. 3 illustrates a signaling chart demonstrating an example STA access procedure 300 in a VBSS mesh network according to some embodiments of the present disclosure. For the purpose of discussion, the STA access procedure 300 will be described with reference to FIGs. 1 and 2.

In the STA access procedure 300, the STA 120 broadcasts a probe request to all of the APs, i.e. root AP 110-1, extended AP1 110-2 and extended AP2 110-3 (step 310) . The root AP 110-1 starts a serving AP selection procedure upon receipt of the probe request. Further, upon receipt of the probe request, all the extended APs (in this example, the extended AP1 110-2 and the extended AP2 110-3) may send a probe response to the STA 120 without waiting for a token distribution indication being sent from the root AP 110-1 indicating that a certain device is selected as the serving device for the STA 120, in response of receiving the probe request from the STA 120, and the root AP 110-1 may also send a probe response to the STA 120 without waiting for the serving AP selection procedure is finished (step 350, refined in FIG. 6) . In addition to or alternatively, in some embodiments, in response of receipt of the probe request from the STA 120, only APs with a RSSI value higher than a threshold may send a probe response to the STA 120 without waiting for a token distribution indication being sent from the root AP 110-1. For example, if the extended AP1 110-2 has a RSSI value which is higher than its threshold, it may send a probe response to the STA 120 upon receipt of the probe request from the STA 120, without waiting for a token distribution indication being sent from the root AP 110-1. If the root AP 110-1 has a RSSI value which is higher than its threshold, it may also send a probe response to the STA 120, without waiting for the serving AP selection procedure is finished. Such a threshold may be pre-configured by the root AP 110-1 or pre-defined in each of the APs. As a result, the probe response procedure is substantially in parallel with the serving AP selection procedure, as illustrated in FIG. 3.

As illustrated in FIG. 3, and with reference to FIG. 2 (240) , the extended AP1 is selected as the serving device for the STA 120 in the serving AP selection procedure (which will be described in detail below in connection with FIG. 5) , and a token distribution indication indicating that the extended AP1 110-2 is selected as the serving device for the STA 120 is sent from the root AP 110-1 to the all the extended APs (in this example, the extended AP1 110-2 and extended AP2 110-3) . The token distribution indication is received by the extended AP1 110-2 before authentication request from the STA 120 is received by the extended AP1 110-2 (step 360) . From the time point when the token distribution indication is received by the extended AP1 110-2, only extended AP1 110-2, the selected serving AP for the STA 120, may receive request from the STA 120 and send signaling and data to the STA 120. The other extended AP, i.e. the extended AP2 110-3, upon receiving the token distribution indication indicating that the extended AP1 110-2 (not extended AP2 110-3 itself) is selected as the serving device for the STA 120, may become aware that it is not the selected serving AP for the STA 120, so will not respond to request from the STA 120 anymore. For the root AP 110-1, since it has sent out the token distribution indication indicating an extended AP (in this example, the extended AP1 110-2) is selected as the serving AP for the STA 120, it will not respond to request from the STA 120 anymore, either.

Specifically, in response to receiving the authentication request from the STA 120, the extended AP1 110-2 sends an authentication response to the STA 120 (step 370) . Neither the extended AP2 110-3 nor the root AP 110-1 will send an authentication response to the STA 120. In step 380, the STA 120 sends an association request to the extended AP1 110-2 and the extended AP1 110-2 receives the association request from the STA 120. In response to receipt of the association request, the extended AP1 110-2 may send an association response to the STA 120 (step 390) ; neither the extended AP2 110-3 nor the root AP 110-1 will send an association response to the STA 120.

FIG. 4 illustrates a signaling chart demonstrating an example STA access procedure 400 in a VBSS mesh network according to some embodiments of the present disclosure. For purpose of discussion, the STA access procedure 400 will be described with reference to FIGs. 1-3.

FIG. 4 differs from FIG. 3 in that at the time when all the APs receive an authentication request from the STA 120, none of the extended APs has received a token distribution indication indicating which extended AP is selected as the serving device for the STA 120, because the serving AP selection procedure at the root AP 110-1 has not been finished. In this case, all APs (including the root AP 110-1) may send an authentication response to the STA 120. Later, before the association request from the STA 120 is received from the STA 120, the extended AP1 110-2 receives the token distribution indication indicating that the extended AP1 110-2 is selected as the serving device for the STA 120 from the root AP 110-1. The token distribution indication is received by the extended AP1 110-2 before association request from the STA 120 is received by the extended AP1 110-2 (step 450) . From the time point when the token distribution indication is received by the extended AP1 110-2, only extended AP1 110-2, the selected serving AP for the STA 120, may receive request from the STA 120 and send signaling and data to the STA 120. The other extended AP, i.e. the extended AP2 110-3, upon receiving the token distribution indication indicating that the extended AP1 110-2 (not extended AP2 110-3 itself) is selected as the serving device for the STA 120, may become aware that it is not the selected serving AP for the STA 120, so it will not respond to request from the STA 120 anymore. For the root AP 110-1, since it has sent out the token distribution indication indicating an extended AP (in this example, the extended AP1 110-2) is selected as the serving AP for the STA 120, it will not respond to request from the STA 120 anymore, either.

In this case, as illustrated in FIG. 4, the serving AP selection procedure at the root AP 110-1 is performed substantially in parallel with probe response procedure and authentication procedure. In other words, as illustrated in FIG. 4 the serving AP selection procedure is overlapping with the probe response procedure and authentication procedure in time domain. Herein, the probe response procedure involves all APs (including the root AP 110-1) sending a probe response to the STA 120 (step 450, as indicated by a dotted rectangle in FIG. 4) , and the authentication response procedure involves the STA 120 sending an authentication request to all APs (step 460) and all APs sending an authentication response to the STA 120 (step 470, as indicated by a dotted rectangle in FIG. 4) .

Specifically, in response to receiving the association request from the STA 120 (step 480) , the extended AP1 110-2 may send an association response to the STA 120 (step 490) ; neither the extended AP2 110-3 nor the root AP 110-1 will send an association response to the STA 120.

In some embodiments of the present disclosure, in contrast to the existing STA access procedure, all the APs with sufficiently high RSSI value (instead of only the serving AP;for example, the extended AP1 110-2 illustrated in FIGs. 3-4) can send the probe response to the STA 120 immediately without waiting for the serving AP indication from the root AP 110-1. In this way, the STA 120 can continue to proceed to the authentication procedure without waiting for the probe response from a potential serving AP. In addition, the serving AP selection procedure can happen substantially in parallel with probe response procedure (and authentication procedure) , which is beneficial to reduce the latency as compared with the initial access procedure as illustrated in FIG. 2.

According to some embodiments of the present disclosure, the STA 120 may broadcast the probe request frame on each channel periodically to search for available APs and their corresponding security capabilities. Typically, the STA 120 may stay in a channel to receive probe response for 20 ms after sending probe request frame, and then move to next channel to perform a new scan operation. If the STA 120 has not received the probe response from any of the APs, it may perform the scan operation again to discover the VBSS mesh network.

FIG. 5 illustrates a signaling chart 500 demonstrating an example serving AP selection process in a VBSS mesh network according to some embodiments of the present disclosure. As illustrated in FIG. 5, upon receiving the probe request from the STA 120, all extended APs in the VBSS mesh network (in this example, the extended AP1 110-2 and the extended AP2 110-3) may apply for the token from the root AP node, to be used to communicate with the STA 120. In other words, in response to receipt of the probe request from the STA 120, all extended APs in the VBSS mesh network may send a token request to the root AP node to be used to communicate with the STA 120. Specifically, upon receipt of the probe request from the STA 120, the extended AP1 110-2 may send a token request to the root AP 110-1 (step 520-1) , and the extended AP2 110-3 may also send a token request to the root AP 110-1 (step 520-2) .

In response to receipt of the token requests from the extended APs (i.e. the extended AP1 110-2 and the extended AP2 110-3) , the root AP 110-1 may perform serving AP decision (step 530) . In this step, the root AP 110-1 may first try to find the token information of the STA 120 in the local database. If the root AP 110-1 fails to find the token information of the STA 120 in the local database, it may select one serving AP in accordance with certain strategies, like RSSI or load balance, etc. For example, the root AP 110-1 may select a certain extended AP as the serving AP based on RSSI and/or load balance information of each extended AP in the VBSS mesh network to determine and select the serving AP.

In the example as illustrated in FIG. 5, it is assumed that the extended AP1 110-2 has been chosen as the serving AP, which will communicate with the STA 120, and the root AP 110-1 distributes the token to the extended AP1 110-2 by sending a token distribution indication to all extended APs in the VBSS mesh network. Specifically, the token distribution indication indicates that the extended AP1 110-2 has been selected as the serving AP for the STA 120 and has the token and thus permitted to communicate with the STA 120. The root AP 110-1 may send the token distribution indication to the serving AP (in this example, the extended AP1 110-2) (540-1) to tell the extended AP1 110-2 has been selected to be the serving AP for the STA 120 such that the serving AP may respond to later-coming request (s) from the STA 120, and the root AP 110-1 may also send the token distribution indication to the non-serving AP (in this example, the extended AP2 110-3) (540-2) to tell the extended AP1 110-2 has been selected to be the serving AP for the STA (The root AP 110-1 may accomplish this through a new signaling) such that the extended AP2 110-3 will not respond to later-coming request (s) from the STA 120 anymore.

The extended AP1 110-2, upon receiving the token distribution indication (step 540-1) , may be aware that it is the serving AP for the STA 120, so it will respond to later-coming request (for example, authentication request and association request) from the STA 120.

The non-serving APs (i.e., the extended AP2 110-3) of the VBSS mesh network, upon receiving the token distribution indication (step 540-2) , may be aware that the extended AP1 110-2, rather than itself, it is the serving AP for the STA 120, so it will not respond to the later-coming request (s) (for example, authentication request and association request) from STA 120 anymore.

As for the root AP 110-1, since it has sent out the token distribution indication indicating an extended AP (in this example, the extended AP1 110-2) is selected as the serving AP for the STA 120, it will not respond to later-coming request (s) from the STA 120 anymore, either.

The token distribution indication can be transmitted to the selected extended AP (in this example, the extended AP1 110-2) , for example, through Client Association Control Request message as in Multi-AP specification.

The token distribution indication could include at least an STA MAC address, a Validity Period or expire time, a Key information, a BSSID, and an Indicate if it is the token owner (i.e., serving AP) .

The transmission occasion of the token distribution indication may be that, when an authentication request comes from the STA 120, the serving AP selection procedure has not been finished by the root AP 110-1. In this case, the root AP 110-1 may transmit the message of token distribution indication to the extended APs before the time when the extended AP transmits the message of authentication response. And the serving AP selection procedure can happen substantially in parallel with that of the probe response procedure, as described above and illustrated in FIG. 3.

In some embodiments, the transmission occasion of the token distribution indication may be that, when an association request comes from the STA 120, the serving AP selection procedure has not been finished by the root AP 110-1. In this case, the serving AP selection procedure can happen substantially in parallel with the probe response procedure and authentication procedure, as described above and illustrated in FIG. 4. In this case, the root AP 110-1 may transmit the token distribution indication to the extended APs, and the extended APs may receive the token distribution indication before the extended AP may transmit an association response. Then, only the selected serving AP (in this example, the extended AP1 110-2) may respond to the STA 120 and send an association response to the STA 120, and take charge of the coming communication with the STA 120.

In some embodiments, it may be the case that, when an association request is received from the STA 120 while the serving AP for the STA 120 has not been decided by the root AP 110-1, the root AP 110-1 may, upon receipt of the association request from the STA 120, send an association response to the STA 120, and take charge of the coming communication with the STA 120.

In some embodiments, it may be the case that, when an association request is received from the STA 120 while the serving AP for the STA 120 has not been decided by the root AP 110-1, and the root AP 110-1 itself does not meet the requirements (i.e., its RSSI value is not high enough, for example, its RSSI value is below a pre-configured or pre-defined threshold) , all the extended APs need to wait for the token distribution indication from the root AP 110-1.

In some embodiments, after receiving the probe requests from the STA 120, surrounding APs may need to determine whether to send the probe response or not, i.e., based on the RSSI and whether the token for serving AP has been assigned. Here the STA 120 may send the probe request periodically, so the extended APs need to send the corresponding probe response periodically.

In some embodiments, the serving AP has been assigned before the probe response. For example, the extended AP1 110-2 has been assigned before the probe response. In this case, only the serving AP, i.e., the extended AP1 110-2 will send the probe response. The other APs, i.e., none of the other extended AP2 110-3 and the root AP 110-1 will send a probe response.

FIG. 6 illustrates a signaling chart demonstrating an example probe response procedure in a VBSS mesh network according to some embodiments of the present disclosure.

In some embodiments, the serving AP has not been assigned till timing of sending a probe response. In this case, all of the expended AP1 110-2, expended AP2 110-3 and root AP 110-1 (if the root AP 110-1 has Wi-Fi ability) of the VBSS mesh network receive the probe request frame send by the STA 120. Each of the APs will first compare the RSSI value with one threshold, if the RSSI value is higher than its threshold, the AP will send the response to the STA 120 immediately. So, there may be multiple APs responding to the STA 120. The detailed procedure and signaling of this procedure is illustrated in FIG. 6. For better understanding, we assume the root AP 110-1 has Wi-Fi ability, and all the APs including the root AP 110-1, the extended AP1 110-2 and AP2 110-3 have sufficiently high RSSI value (each of them has a RSSI value which is higher than its threshold) .

Here the threshold of each AP can be configured by the root AP 110-1 or pre-configure in each AP. For example, it can be set the same value with RCPI (Received channel power indicator) threshold in Wi-Fi Alliance Multi-AP specification, via Multi-AP Policy Config Request message. It also can be configured with another value.

Specifically, as illustrated in FIG. 6, upon receipt of the probe request from STA 120, the extended AP1 110-2 may send a probe response to the STA 120 (step 350-2) , the extended AP2 110-3 may also send a probe response to the STA 120 (step 350-3) , and the root AP 110-1 may also send a probe response to the STA 120 (step 350-1) .

FIG. 7 illustrates a signaling chart demonstrating an example authentication procedure in a VBSS mesh network according to some embodiments of the present disclosure.

In some embodiments of the present disclosure, the STA 120 may send an authentication request frame to all surrounding APs (step 460) . After receiving the authentication request from the STA 120, the extended AP (s) needs to determine whether to send the authentication response based on the token distribution indication from the root AP 110-1. Here, the root AP 110-1 also can send authentication response frame if the root AP 110-1 has Wi-Fi ability, as illustrated in FIG. 7.

In some embodiments, the extended AP1 110-2 has not received the token distribution indication from the root AP 110-1 before it has received the authentication request from STA 120, as illustrated in FIG. 4. In such a case, the extended APs with sufficiently high RSSI value (assuming both extended AP1 110-2 and extended AP2 110-3 having sufficiently high RSSI value) may continue to send authentication response to the STA 120, as illustrated in FIG. 7. The root AP 110-1 with sufficiently high RSSI value also can send the authentication response to the STA 120 if the root AP 110-1 has Wi-Fi ability, as illustrated in FIG. 7.

Specifically, as illustrated in FIG. 7, upon receipt of the authentication request from STA 120 (step 460) , the extended AP1 110-2 may send an authentication response to the STA 120 (step 470-2) , the extended AP2 110-3 may also send an authentication response to the STA 120 (step 470-3) , and the root AP 110-1 may also send an authentication response to the STA 120 (step 470-1) .

The STA 120 may try to associate with the serving AP (i.e., extended AP1 110-2) . Through the association, the STA 120 and extended AP1 110-2 have established a secure session for data transmission.

According to some embodiments of the present disclosure, each extended APs (in this example, the extended AP1 110-2 and the extended AP2 110-3) needs to determine whether it needs to send the authentication response according to the received token distribution indication from the root AP 110-1.

In some embodiments of the present disclosure, the extended AP1 110-2 has been selected as the serving AP (i.e., Token owner) , then it may send authentication response to the STA 120.

In some embodiments of the present disclosure, the extended AP2 110-3 has not been selected as the serving AP (i.e., not the token owner) , then it may not send authentication response to the STA 120. Additionally or alternatively, in some embodiments, the extended AP1 110-2 has not received the token distribution indication from the root AP 110-1 before the time when it has received the authentication request from the STA 120. For example, in some embodiments, all the extended APs with sufficiently high RSSI value will continue to send authentication response to the STA.

According to embodiments of the present disclosure, the serving AP selection procedure can be performed substantially in parallel with other steps such as probe response (and authentication request and response) , the AP nodes with sufficiently high RSSI value can send the probe response or/and authentication response accordingly before a token distribution indication from the root AP 110-1 is received, which will result in significantly latency reduction.

In this way, the latency in the discovery and authentication procedure can be reduced by sending corresponding response in advance without waiting for the serving AP selection procedure to be finished. The probe request re-transmission at STA 120 can also be reduced since the STA 120 can quickly receive the probe response from the extended APs in the mesh network. In addition, the serving AP selection procedure can happen substantially in parallel with the probe response procedure (and authentication procedure) , further reducing the latency in access/roaming procedure of the STA 120.

FIG. 8 shows a flowchart of an example method 800 executed in the root AP 110-1 in a VBSS based mesh network according to some example embodiments of the present disclosure. The method 800 can be implemented at the root AP 110-1 as shown in FIG. 1. For the purpose of discussion, the method 800 will be described also with reference to FIG. 1.

At block 810, the root AP 110-1 receives a probe request from a terminal device.

At block 820, upon receipt of the probe request, based on its Received Signal Strength Indication (RSSI) being higher than a threshold, the root AP 110-1 sends a probe response to the terminal device to send an authentication request.

At block 825, substantially in parallel with sending the probe response, the root AP 110-1 receives a token request from one or more extended APs.

At block 835, the root AP 110-1 selects a serving AP for the STA 120 from one or more extended APs.

At block 845, the root AP 110-1 sends a token distribution indication to the one or more extended APs. The token distribution indication indicates that the serving AP has the token and is permitted to communicate with the STA 120.

FIG. 9 shows a flowchart of an example method 900 of the extended AP in a VBSS based mesh network according to some example embodiments of the present disclosure. The method 900 can be implemented at the second device (for example, the extended AP1 110-2) as shown in FIG. 1. For the purpose of discussion, the method 900 will be described also with reference to FIG. 1.

At block 910, the second device receives a probe request from a terminal device.

At block 920, upon receipt of the probe request, the second device sends a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has the token and is permitted to communicate with the terminal device.

FIG. 10 is a simplified block diagram of a device 1000 that is suitable for implementing embodiments of the present disclosure. The device 1000 may be provided to implement the communication device, for example the extended AP1 110-2 or the root AP 110-1 as shown in FIGs. 1 and 3. As shown, the device 1000 includes one or more processors 1010, one or more memories 1020 coupled to the processor 1010, and one or more transmitters and/or receivers (TX/RX) 1040 coupled to the communication module 1070.

The TX/RX 1040 is for bidirectional communications. The TX/RX 1040 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 1010 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1000 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 1020 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1024, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1022 and other volatile memories that will not last in the power-down duration.

A computer program 1030 includes computer executable instructions that are executed by the associated processor 1010. The program 1030 may be stored in the ROM 1024. The processor 1010 may perform any suitable actions and processing by loading the program 1030 into the RAM 1022.

The embodiments of the present disclosure may be implemented by means of the program 1030 so that the device 1000 may perform any process of the disclosure as discussed with reference to FIGs. 3 to 7. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments according to the present disclosure, a first device is provided. The first device comprises a processor configured to perform the functions of the root AP 110-1 illustrated herein.

In some example embodiments according to the present disclosure, a second device is provided. The second device comprises a processor configured to perform the functions of the extended AP1 110-2 or the extended AP2 110-3 illustrated herein.

In some embodiments, the program 1030 may be tangibly contained in a computer readable medium which may be included in the device 1000 (such as in the memory 1020) or other storage devices that are accessible by the device 1000. The device 1000 may load the program 1030 from the computer readable medium to the RAM 1022 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. FIG. 11 shows an example of the computer readable medium 1100 in form of CD or DVD. The computer readable medium has the program 1030 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, device, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

methods

800 and 900 as described above with reference to FIGs. 3-9. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing device, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, device or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms to implement the claims.

Claims

A first device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the first device to:

receive a probe request from a terminal device;

upon receipt of the probe request, send a probe response to the terminal device to send an authentication request;

substantially in parallel with sending the probe response, receive a token request from one or more second devices;

select a serving device from the one or more second devices; and

send a token distribution indication to the one or more second devices indicating that the serving device has the token and is permitted to communicate with the terminal device.
The first device of claim 1, wherein the first device and the one or more second devices are accessible to the terminal device via a same identifier.
The first device of claim 1, wherein the first device sends a probe response to the terminal device based on its Received Signal Strength Indication (RSSI) value being higher than a threshold.
The first device of claim 1 or 2, wherein the first device is further caused to:

receive an authentication request from the terminal device; and

upon receipt of the authentication request, if the token distribution indication is not sent yet, send an authentication response to the terminal device to send an association request.
The first device of claim 4, wherein the first device is further caused to:

receive an association request from the terminal device; and

upon receipt of the association request, send an association response to the terminal device if the token distribution indication is not sent yet.
A second device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the second device to:

receive a probe request from a terminal device; and

upon receipt of the probe request, send a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has a token and is permitted to communicate with the terminal device.
The second device of claim 6, wherein the second device sends a probe response to the terminal device based on its Received Signal Strength Indication (RSSI) value being higher than a threshold.
The second device of claim 6, wherein the second device is further caused to:

upon receipt of the probe request, send a token request to the first device; and

receive the token distribution indication from the first device.
The second device of claim 8, wherein the second device is further caused to:

receive an authentication request from the terminal device; and

upon receipt of the authentication request, send an authentication response to the terminal device in either of the following situations:

the token distribution indication is received indicating that the second device itself is the serving device; or

no token distribution indication from the first device is received.
The second device of claim 9, wherein the second device is further caused to:

receive an association request from the terminal device; and

upon receipt of the association request, send an association response to the terminal device if the token distribution indication is received indicating that the second device itself is the serving device.
A mesh network, comprising a first device according to any of claims 1-5 and one or more second devices according to any of claims 6-10.
A method implemented in a first device, comprising:

receiving a probe request from a terminal device;

upon receipt of the probe request, sending a probe response to the terminal device to send an authentication request;

substantially in parallel with sending the probe response, receiving a token request from one or more second devices;

selecting a serving device from the one or more second devices; and

sending a token distribution indication to the one or more second devices indicating that the serving device has the token and is permitted to communicate with the terminal device.
The method of claim 12, wherein the first device and the one or more second devices are accessible to the terminal device via a same identifier.
The method of claim 12, wherein the sending the probe response to the terminal device comprises

sending the probe response to the terminal device based on a Received Signal Strength Indication (RSSI) value of the first device being higher than a threshold.
The method of claim 12 or 13, wherein further comprises:

receiving an authentication request from the terminal device; and

upon receipt of the authentication request, if the token distribution indication is not sent yet, sending an authentication response to the terminal device to send an association request.
The method of claim 15, wherein further comprises:

receiving an association request from the terminal device; and

upon receipt of the association request, sending an association response to the terminal device if the token distribution indication is not sent yet.
A method implemented in a second device, comprising:

receiving a probe request from a terminal device; and

upon receipt of the probe request, sending a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has a token and is permitted to communicate with the terminal device.
The method of claim 17, wherein sending the probe response to the terminal device comprises

sending the probe response to the terminal device based on a Received Signal Strength Indication (RSSI) value of the second device being higher than a threshold.
The method of claim 17, wherein the method further comprises:

upon receipt of the probe request, sending a token request to the first device; and

receiving the token distribution indication from the first device.
The method of claim 19, wherein the method further comprises:

receiving an authentication request from the terminal device; and

upon receipt of the authentication request, sending an authentication response to the terminal device in either of the following situations:

the token distribution indication is received indicating that the second device itself is the serving device; or

no token distribution indication from the first device is received.
The method of claim 20, wherein the method further comprises:

receiving an association request from the terminal device; and

upon receipt of the association request, sending an association response to the terminal device if the token distribution indication is received indicating that the second device itself is the serving device.
An apparatus implemented in a first device, comprising:

means for receiving a probe request from a terminal device;

means for sending, upon receipt of the probe request from the terminal device, a probe response to the terminal device to send an authentication request;

means for receiving, substantially in parallel with sending the probe response, a token request from one or more second devices;

means for selecting a serving device from the one or more second devices; and

means for sending a token distribution indication to the one or more second devices indicating that the serving device has a token and is permitted to communicate with the terminal device.
An apparatus implemented in a second device, comprising:

means for receiving a probe request from a terminal device; and

means for sending, upon receipt of the probe request, a probe response to the terminal device to send an authentication request, without waiting for a token distribution indication being sent from a first device indicating that a serving device has a token and is permitted to communicate with the terminal device.
A computer-readable storage medium having instructions stored thereon, the instructions, when executed on at least one processor, cause the at least one processor to perform the method of any of claims 12-16, or the method of any of claims 17-21.