WO2025148018A1

WO2025148018A1 - Multi-access-point communications for wireless networks

Info

Publication number: WO2025148018A1
Application number: PCT/CN2024/072055
Authority: WO
Inventors: Jianfei CHENG; Bo Sun; Zhe LIU; Yu Chen; Aijuan Feng
Original assignee: Sanechips Technology Co Ltd
Current assignee: Sanechips Technology Co Ltd
Priority date: 2024-01-12
Filing date: 2024-01-12
Publication date: 2025-07-17
Anticipated expiration: 2026-07-12

Abstract

Systems, methods, and apparatus for wireless networking are described. The methods improve the efficiency of wireless networking by coordinating transmissions among sharing and shared access points (APs). An example wireless networking method includes transmitting, by a sharing access point (AP), a trigger frame associated with a multi-AP coordinated transmission. The method further includes receiving, by the sharing AP, a response frame indicating an idle status of a channel associated with a shared AP, where the sharing AP and the shared AP are included in a coordinated set. The method further includes transmitting, by the sharing AP and in response to receiving the response frame, an instruction initiating the multi-AP coordinated transmission.

Description

MULTI-ACCESS-POINT COMMUNICATIONS FOR WIRELESS NETWORKS

TECHNICAL FIELD

This patent document is directed generally to wireless networking.

BACKGROUND

With the rapid development of computers and the Internet, Wireless Local Area Network (WLAN) technology has gained increasing attention. WLAN technology, based on short-range wireless communication, allows mobile devices such as smartphones, tablets, laptops, and multimedia players to wirelessly access the Internet in homes, offices, or specific service areas. This technology enables convenient and flexible connectivity, empowering users to access online services and resources without the constraints of wired connections. WLAN has become an essential part of modern communication infrastructure, providing seamless connectivity and enhancing productivity in various environments.

WLAN often utilizes the technologies defined by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards, including the Medium Access Control (MAC) and Physical Layer (PHY) protocols. The IEEE has commercialized or developed various technical standards to meet the growing network demands.

SUMMARY

The disclosed embodiments, among other features and benefits, describe a frame exchange process for performing a coordinated transmission in a multiple-access-point (AP) wireless network. Among other things, the patent document discloses a trigger frame, a response frame, a physical layer protocol data unit (PPDU) transmission, and when to abandon a coordinated transmission.

A first example wireless networking method includes transmitting, by a sharing access point (AP) , a trigger frame associated with a multi-AP coordinated transmission. The method further includes receiving, by the sharing AP, a response frame indicating an idle status of a channel associated with a shared AP, where the sharing AP and the shared AP are included in a coordinated set. The method further includes transmitting, by the sharing AP and in response to receiving the response frame, an instruction initiating the multi-AP coordinated transmission.

A second example wireless networking method includes receiving, by a shared access point (AP) , a trigger frame associated with a multi-AP coordinated transmission. The method further includes determining, by the shared AP and based on a busy or idle status of a channel associated with the shared AP, whether to reply to the trigger frame with a response frame.

A third example wireless networking method includes determining, by a sharing access point (AP) , that no shared AP is available for a multi-AP coordinated transmission. The method further includes abandoning, by the sharing AP, the multi-AP coordinated transmission.

Note that where the patent document discloses a method of transmitting an information by a first network device to a second network device, it will be understood that a method of receiving the information by the second network device from the first network device is also disclosed.

In yet another example embodiment, a device that is configured or operable to perform the above-described methods is disclosed. The device includes at least one processor configured to implement the above-described methods.

In yet another example embodiment, the above-described methods are embodied in the form of processor-executable code and stored in a non-transitory computer-readable storage medium. The code included in the computer readable storage medium when executed by a processor, causes the processor to implement the methods described in this patent document.

The above and other aspects and their implementations are described in greater detail in the drawings, the descriptions, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example wireless local area network (WLAN) .

FIG. 2 illustrates an example node access process.

FIG. 3 illustrates an example communication system between access points (APs) and stations (STAs) .

FIG. 4 illustrates an example multi-AP coordinated transmission.

FIG. 5 illustrates an example AP.

FIG. 6 illustrates an example coordinated transmission among sharing and shared APs.

FIG. 7 illustrates an example coordinated transmission where some shared APs are busy.

FIG. 8 illustrates an example abandoned coordinated transmission.

FIG. 9 is an example flowchart for performing a coordinated transmission.

FIG. 10 is an example flowchart for determining a busy AP.

FIG. 11 is an example flowchart for abandoning a coordinated transmission.

DETAILED DESCRIPTION

In this document, wireless local area network (WLAN) terminology is used for the sake of clarity of explanation, but the techniques disclosed in the present document are not limited to WLAN technology only and may be used in wireless networking systems that implemented other protocols.

In recent years, with the rapid development of computers and the Internet, wireless Internet service wireless local-area network (WLAN) technology has attracted more and more attention. WLAN technology is based on short-range wireless communication technology and allows mobile devices such as smartphones, smart computers, notebook computers, and multimedia players to wirelessly access the Internet in homes, companies, or specific service areas.

WLAN uses technologies defined by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards, including Media Access Control (MAC) and Physical Layer (Physical Layer, PHY) protocols. IEEE 802.11 has commercialized or developed various technical standards to meet the growing network needs. However, with the explosive application of WLAN, the deployment of WLAN networks continues to become denser, the network load continues to increase, and the network overlapping phenomenon becomes more serious. The traditional network deployment technology based on frequency reuse can no longer meet the needs, and the efficiency of WLAN networks has experienced a clear downward trend.

802.11MAC uses the distributed coordination function (DCF Distribution System, DS) , and DCF relies on multiple access technology based on collision avoidance/carrier sensing multiple access (CSMA/CA) . CSMA/CA requires the device to monitor the channel before sending data and determine whether to send data or perform a backoff operation based on the monitoring results. If the channel is occupied, the device waits for a random amount of time before trying to send again.

Multi-access point coordination technology refers to technology that provides better coverage, capacity, and performance through coordination between multiple access points (Access Points, APs) . Traditional single AP deployment may face problems such as limited coverage and signal interference. Multi-AP coordination technology can solve problems such as heavy network load and severe network overlap by connecting multiple APs to the same wireless network and implementing coordinated behaviors.

However, in the current multi-access coordination technology, the access point can access the channel without using the CSMA/CA mechanism, so it may cause serious interference to other transmitting links. In addition, there is currently no relevant solution to the problem that coordinated transmission resources may be wasted in burst coordinated transmission.

FIG. 1 illustrates a schematic diagram of a WLAN network for an embodiment of the present patent document. The WLAN network includes one or more Basic Service Sets (BSS) , which represent a group of devices that are successfully associated and communicate with each other. Different BSSs can be distinguished using BSS identification (BSSID) information. The BSS identification information includes the BSSID carried in the MAC frame header and the BSS Color carried in the PHY frame header. As shown in FIG. 1, the Basic Service Set (BSS) includes multiple stations (STA1, STA2, STA3, STA4, and STA5) , access points (AP1 and AP2) that provide access services, and a distribution system (DS) that connects multiple access points.

A station refers to a device that complies with the provisions of the IEEE 802.11 standard. It can be a wireless terminal device such as a laptop, smartphone, tablet, or any other device that supports wireless connectivity. A station can function as a client or an access point (AP) in a wireless network. In the 802.11 standard, stations communicate with each other over the wireless channel and can perform operations such as data transmission, receiving broadcast messages, and roaming. Each station has a unique physical address known as the Media Access Control (MAC) address, which is used for identification and addressing within the wireless network.

An access point (AP) acts as an entity that provides access to a distribution system (DS) for the stations associated with it. In infrastructure mode, stations scan the wireless channels to search for and connect to nearby access points. Non-AP stations communicate with other stations through access points and can also access wired network resources via the access points. Apart from infrastructure mode, access points can also be used in ad-hoc mode, where multiple stations can directly communicate in a point-to-point or peer-to-peer manner, forming a self-organizing wireless network.

Access points serve as Personal Coordination Points (PCP) in the concept of Personal BSS. In the present patent document, access points, in a broad sense, include APs, base stations, and evolved NodeBs (eNodeBs) . Additionally, various types of wireless communication terminals can be included, which allocate wireless resources and perform scheduling for multiple wireless communication terminals.

Typically, a station (STA) is associated with a single AP at a time. The associated AP can store information related to the STA, such as the Association ID (AID) , keys, sequence numbers, traffic flow identifiers, Block Ack protocol-related information, and other STA-specific information. The STA can communicate with other STAs through the AP or, after establishing a direct link with other STAs, can communicate directly with those STAs.

FIG. 2 represents the Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) method used for channel access in node-to-node communication. Before sending data, wireless devices first listen to the wireless channel to detect if other devices are transmitting data. If the received signal strength exceeds a predetermined threshold known as the Clear Channel Assessment (CCA) threshold, the channel is considered busy, and the wireless device delays the channel access. This process is known as Clear Channel Assessment (CCA) . If no signal is detected or the signal strength is below the CCA threshold, the channel is considered idle.

Additionally, the indication of channel busy or idle also relies on the Network Allocation Vector (NAV) . The purpose of NAV is to establish a protection period on the wireless channel to prevent other devices from transmitting data during that period. The value of NAV is calculated based on the expected time required by the transmitting device, including data transmission time and transmission delays between devices. When other devices receive frames carrying NAV, they remain silent and refrain from sending data during the indicated NAV time to avoid collisions.

As discussed in this context, it is possible for multiple APs to communicate with the same or different STAs simultaneously. Multiple APs can transmit the same data or different data to the STAs.

FIG. 3 illustrates a communication system between APs and STAs. The communication system includes AP1, AP2, STA1, and STA2. In some embodiments, AP1 and AP2 can be base stations, while STA1 and STA2 can be user equipments (UEs) . Unlike the scenario where an STA can only communicate with one AP at a time, this communication system allows AP1 and AP2 to communicate simultaneously with STA1 and STA2, or with both STA1 and STA2 simultaneously. For example, AP1 and AP2 can simultaneously send data to STA1, or they can simultaneously send data to STA2. Alternatively, AP1 and AP2 can transmit data to STA1 and STA2 at the same time, but with different content. To achieve such communication modes, AP1 and AP2 typically need to exchange information to ensure that data can be simultaneously delivered to STA1 or STA2. For instance, AP1 or AP2 can send trigger frames or synchronization frames to synchronize the start of transmission between AP1 and AP2.

Multi-access point (AP) coordinated transmission technology refers to the technique where multiple access points coordinate in transmitting data. Coordinated transmission technology can be divided into cooperative transmission and joint transmission. Cooperative transmission involves multiple access points sharing wireless resources such as frequency, space, or time and using techniques such as cooperative beamforming (C-BF) , cooperative spatial reuse (C-SR) , cooperative orthogonal frequency-division multiple access (C-OFDMA) , and cooperative time-division multiple access (C-TDMA) to transmit data to multiple stations (STAs) simultaneously. Joint transmission involves multiple access points sharing wireless resources such as frequency, space, or time and using techniques such as joint single-user multi-input multi-output (J-SUMIMO) or joint multi-user multi-input multi-output (J-MUMIMO) to transmit data simultaneously to the same station. The STA combines the data received from multiple access points into the final received data using a certain strategy or algorithm.

AP1 and AP2 can declare their supported multi-access point transmission capabilities. Specifically, the multi-access point transmission capabilities include cooperative beamforming (C-BF) , cooperative spatial reuse (C-SR) , cooperative orthogonal frequency-division multiple access (C-OFDMA) , cooperative time-division multiple access (C-TDMA) , joint single-user multi-input multi-output (J-SUMIMO) , joint multi-user multi-input multi-output (J-MUMIMO) , and others. The access points can negotiate the cooperative/joint transmission techniques they will use. For example, AP1 and AP2 can exchange information about the multi-access point transmission modes they individually support. Subsequently, AP1 and AP2 can select a mutually agreed-upon multi-access point transmission mode. The negotiation for selecting the multi-access point transmission mode takes place before transmitting data to the STAs. During the negotiation, in addition to selecting the multi-access point transmission mode, AP1 and AP2 can also exchange data for transmitting to STA1 or STA2 using joint transmission mode.

FIG. 4 represents a schematic diagram of an implementation example of multi-access point coordinated transmission. Multiple access points can be divided into two categories: sharing AP (also known as the master AP) and shared AP (also known as the slave AP) . The sharing AP or master AP is responsible for coordinating and controlling the other APs in the coordinated transmission. It plays the role of a coordinator, scheduling the transmissions of other APs and ensuring their coordination and interoperability. The shared AP or slave AP refers to the APs controlled and scheduled by the sharing AP in the multi-AP coordinated transmission. These APs receive instructions from the sharing AP and perform transmission operations accordingly. The shared APs coordinate with each other through the sharing AP to avoid collisions and improve transmission efficiency. When transmitting data, the shared APs may perform operations such as time slot allocation, power control, and transmission time adjustment based on the instructions of the sharing AP to ensure the smooth operation of coordinated transmission.

The assignment of roles between the sharing AP and shared APs is typically determined through the initialization negotiation of the coordinated transmission set or based on factors such as network topology, AP processing capabilities, AP locations, and coverage areas. Alternatively, it can be determined based on the first AP that completes the backoff process and attempts to access the channel, following the CSMA/CA mechanism.

In the first method, the roles of the sharing AP and shared APs are usually permanent or semi-permanent (relative to the network’s lifecycle) . In the second method, the roles of the sharing AP and shared APs are dynamic and subject to change.

In FIG. 4, the sharing AP accesses the channel and sends a trigger frame (TF) using the CSMA/CA mechanism. The trigger frame typically carries instructions or control information for the shared AP1 and shared AP2. Subsequently, the sharing AP, shared AP1, and shared AP2 access the channel simultaneously for coordinated transmission. The coordinated transmission mode can involve techniques such as cooperative beamforming (C-BF) , cooperative spatial reuse (C-SR) , cooperative orthogonal frequency-division multiple access (C-OFDMA) , and others. These techniques enable coordinated and efficient transmission among the sharing AP and shared APs.

FIG. 5 is a schematic diagram of an example implementation of the access point in this patent document. The access point can include communication units, processors, and memory. Each module is coupled and interconnected to each other via a data communication bus as required.

The communication unit typically represents the hardware, software, firmware, or other components of the access point. It is responsible for sending and receiving wireless signals. The communication unit includes one or more communication modules operating in different frequency bands such as 2.4GHz, 5GHz, and 6GHz. At any given time, the communication unit can operate a single communication module or multiple communication modules simultaneously. Multiple communication modules can be integrated into a single chip. Additionally, the communication module also includes an RF module for processing RF signals. The communication unit also provides an 802.3 Ethernet interface, enabling the access point to communicate with traditional Ethernet-based computer networks.

The processor is responsible for executing various commands or programs and processing the data sent or received. Additionally, the processor controls the data transmission and reception of various modules, such as the communication unit. The processor can be a modulator/demodulator (modem) used to modulate the wireless signals to be transmitted to the communication unit and demodulate the wireless signals received from the communication unit. The processor can be designed as a general-purpose processor, digital signal processor (DSP) , application-specific integrated circuit (ASIC) , field-programmable gate array (FPGA) , or any combination thereof to implement or realize the functionalities described in this document.

The memory stores the control programs and various data used in the access point (AP) . The memory can be implemented as RAM (Random Access Memory) , flash memory, ROM (Read-Only Memory) , EPROM (Erasable Programmable Read-Only Memory) , registers, hard disk, removable disk, Compact Disc Read-Only Memory (CD-ROM) , or any other known form of storage media in the field. The memory can be coupled to the processor, allowing the processor to read information from and write information to the memory.

In some implementations, the memory may include separate caches to store temporary variables or other intermediate information during the execution of instructions by the processor. The memory may also include non-volatile memory to store instructions to be executed by the processor. Upon powering on the device, one or more programs stored on the hard disk or read-only memory are transferred to random access memory and stored in variable and parameter registers required for the present patent document.

The device of the present patent document can be implemented using software, and alternatively, can also be implemented using hardware (ASIC or FPGA) .

FIG. 6 represents a frame exchange process for multi-access point coordinated transmission. Initially, the sharing AP accesses the channel using the Enhanced Distributed Channel Access (EDCA) mechanism and sends a trigger frame. In some implementations, the trigger frame can be a synchronization frame or other types of notification frames. The trigger frame can include the identifiers of the shared AP1 and shared AP2, priority or traffic identifiers for the transmitted data, and necessary information for the shared AP1 and shared AP2 to reply with response frames, such as the physical layer protocol data unit (PPDU) format, resource unit (RU) position, and Modulation and Coding Scheme (MCS) . Allocating shared APs to different RU positions can help avoid conflicts when they reply with response frames. The priority or traffic identifiers can be used to identify the service flows and quality of service (QoS) parameters associated with the transmitted data. The shared AP identifiers can be the MAC addresses of the shared APs or unique identifiers between the APs.

After receiving the trigger frame sent by the sharing AP, shared AP1 and shared AP2 first need to check the busy/idle status of their local channels. This check is performed to avoid causing significant interference to ongoing transmissions. The busy/idle status of the local channel is primarily indicated through the evaluation of the idle channel and the setting of the Network Allocation Vector (NAV) .

Shared APs have the option to reply with response frames in the following cases: Clear Channel Assessment (CCA) and NAV indicate that the current channel is idle. Once the sharing AP receives one or more response frames, it can initiate the coordinated transmission. After a Short Interframe Space (SIFS) interval, both the sharing AP and shared AP1/AP2 start the cooperative/joint transmission simultaneously.

FIG. 7 represents another frame exchange process for multi-access point coordinated transmission. In this case, shared AP2 checks its local channel and determines that it is busy before deciding whether to reply with a response frame.

In the frame exchange process shown in FIG. 7 for shared AP1, it should include at least a response frame + coordinated PPDU + acknowledgment frame and three SIFS durations. Additionally, non-coordinated APs (legacy APs) and other non-AP stations (STAs) should set the NAV in the trigger frame. The response frame sent by shared AP1 should include the NAV value to avoid conflicts with the upcoming coordinated transmission process. The NAV duration can be optionally set to the entire transmit opportunity (TXOP) duration or the minimum duration required for one PPDU frame exchange sequence.

Similarly, in the frame exchange process shown in FIG. 7 for shared AP2, it should include at least a coordinated PPDU + acknowledgment frame and two SIFS durations. Shared AP2, legacy APs, and STAs should also set the NAV duration in the response frame sent by shared AP1.

Indeed, the NAV (Network Allocation Vector) setting mechanism in the trigger frame and response frame helps to mitigate the interference caused by hidden nodes in coordinated transmission.

In FIG. 8, the mechanism of receiving response frames by the sharing AP ensures that at least one shared AP participates in the coordinated transmission to avoid wasting resources.

In the scenario where both shared AP1 and shared AP2 are busy simultaneously, if the sharing AP does not receive at least one response frame within the specified time, it should abandon the current coordinated transmission and restart the backoff process to contend for the channel. If the sharing AP successfully contends for the channel again, it will perform a non-coordinated transmission.

During non-coordinated transmission, the sharing AP can benefit from better transmission parameters compared to coordinated transmission. For example, in C-OFDMA mode, the sharing AP needs to allocate a portion of frequency resources to the shared AP. In C-SR mode, the sharing AP needs to reduce its own transmit power and rate to accommodate the shared AP’s successful transmission. However, during non-coordinated transmission, the sharing AP can utilize the entire frequency resources or use higher transmit power and higher rates.

This allows the sharing AP to optimize its transmission parameters and maximize its own performance during non-coordinated transmission, considering the unavailability of shared APs for coordinated transmission at that time.

This method is applicable to wireless network environments with multiple access points, where access points are divided into primary access points and secondary access points. In this method, the secondary access points receive trigger frames from the primary access point. The secondary access points are configured to respond with acknowledgment frames based on the current channel’s busy or idle status, which is determined through idle channel assessment and NAV (Network Allocation Vector) indication. The primary access point decides whether to engage in coordinated transmission based on the reception of acknowledgment frames.

This method also includes carrying NAV (Network Allocation Vector) in the trigger frames sent by the primary access point and the acknowledgment frames sent by the secondary access points. The duration of this NAV can be chosen as the duration of a complete transmission opportunity or the time required for at least one frame exchange sequence. The secondary access points have the option to ignore the NAV in the trigger frames or update the locally stored NAV. However, in multi-access point transmissions, the abovementioned NAV is ignored.

FIG. 9 is an example flowchart for performing a coordinated transmission. Operation 902 includes transmitting, by a sharing access point (AP) , a trigger frame associated with a multi-AP coordinated transmission. Operation 904 includes receiving, by the sharing AP, a response frame indicating an idle status of a channel associated with a shared AP, where the sharing AP and the shared AP are included in a coordinated set. Operation 906 includes transmitting, by the sharing AP and in response to receiving the response frame, an instruction initiating the multi-AP coordinated transmission. The method can be implemented according to the embodiments described above. In some embodiments, performing further steps of the method can be based on a better system performance than a legacy protocol.

In some embodiments, the method further includes transmitting, by the sharing AP, a physical layer protocol data unit (PPDU) simultaneously with the shared AP in a coordinated mode.

In some embodiments, the trigger frame is a synchronization frame or a notification frame, and the trigger frame includes at least one of an identifier of the shared AP, a priority or a traffic identifier of a transmitted data, or an information necessary for the shared AP to reply with the response frame.

In some embodiments, the identifier of the shared AP is a medium access control (MAC) address or a unique identifier of the shared AP, the priority or the traffic identifier of the transmitted data is used to identify a service flow or a quality of service (QoS) parameter associated with the transmitted data, the information necessary for the shared AP to reply with the response frame includes at least one of a physical layer protocol data unit (PPDU) format, a resource unit (RU) position, or a modulation and coding scheme (MCS) , where the RU position helps avoid a conflict between the response frame and another response frame from another shared AP.

In some embodiments, the idle status of the channel associated with the shared AP is evaluated by a clear channel assessment (CCA) or by setting a network allocation vector (NAV) .

FIG. 10 is an example flowchart for determining a busy AP. Operation 1002 includes receiving, by a shared access point (AP) , a trigger frame associated with a multi-AP coordinated transmission. Operation 1004 includes determining, by the shared AP and based on a busy or idle status of a channel associated with the shared AP, whether to reply to the trigger frame with a response frame. The method can be implemented according to the embodiments described above. In some embodiments, performing further steps of the method can be based on a better system performance than a legacy protocol.

In some embodiments, the channel associated with the shared AP is idle, and the shared AP transmits the response frame.

In some embodiments, the channel associated with the shared AP is idle, and at least one of the following applies: the response frame includes a network allocation vector (NAV) duration that avoids a conflict with an upcoming coordinated transmission; or a NAV duration is set to an entire transmit opportunity (TXOP) duration or a minimum duration required for one physical layer protocol data unit (PPDU) frame exchange sequence.

In some embodiments, the channel associated with the shared AP is busy, and the shared AP does not transmit the response frame.

FIG. 11 is an example flowchart for abandoning a coordinated transmission. Operation 1102 includes determining, by a sharing access point (AP) , that no shared AP is available for a multi-AP coordinated transmission. Operation 1104 includes abandoning, by the sharing AP, the multi-AP coordinated transmission. The method can be implemented according to the embodiments described above. In some embodiments, performing further steps of the method can be based on a better system performance than a legacy protocol.

In some embodiments, determining that no shared AP is available includes receiving, by the sharing AP, no response frame from any shared AP within a specified period of time.

In some embodiments, the method further includes restarting, by the sharing AP, a backoff process to contend for a channel, and performing, by the sharing AP, a non-coordinated transmission after successfully contending for the channel.

Example 1: A wireless networking method, comprising: transmitting, by a sharing access point (AP) , a trigger frame associated with a multi-AP coordinated transmission; receiving, by the sharing AP, a response frame indicating an idle status of a channel associated with a shared AP, wherein the sharing AP and the shared AP are included in a coordinated set; and transmitting, by the sharing AP and in response to receiving the response frame, an instruction initiating the multi-AP coordinated transmission.

Example 2: The method of example 1, further comprising transmitting, by the sharing AP, a physical layer protocol data unit (PPDU) simultaneously with the shared AP in a coordinated mode.

Example 3: The method of example 1 or 2, wherein the trigger frame is a synchronization frame or a notification frame, and wherein the trigger frame comprises at least one of an identifier of the shared AP, a priority or a traffic identifier of a transmitted data, or an information necessary for the shared AP to reply with the response frame.

Example 4: The method of example 3, wherein the identifier of the shared AP is a medium access control (MAC) address or a unique identifier of the shared AP, wherein the priority or the traffic identifier of the transmitted data is used to identify a service flow or a quality of service (QoS) parameter associated with the transmitted data, wherein the information necessary for the shared AP to reply with the response frame comprises at least one of a physical layer protocol data unit (PPDU) format, a resource unit (RU) position, or a modulation and coding scheme (MCS) , and wherein the RU position helps avoid a conflict between the response frame and another response frame from another shared AP.

Example 5: The method of any of examples 1-4, wherein the idle status of the channel associated with the shared AP is evaluated by a clear channel assessment (CCA) or by setting a network allocation vector (NAV) .

Example 6: A wireless networking method, comprising: receiving, by a shared access point (AP) , a trigger frame associated with a multi-AP coordinated transmission; and determining, by the shared AP and based on a busy or idle status of a channel associated with the shared AP, whether to reply to the trigger frame with a response frame.

Example 7: The method of example 6, wherein the channel associated with the shared AP is idle, and wherein the shared AP transmits the response frame.

Example 8: The method of example 6 or 7, wherein the channel associated with the shared AP is idle, and wherein at least one of the following applies: the response frame comprises a network allocation vector (NAV) duration that avoids a conflict with an upcoming coordinated transmission; or a NAV duration is set to an entire transmit opportunity (TXOP) duration or a minimum duration required for one physical layer protocol data unit (PPDU) frame exchange sequence.

Example 9: The method of example 6, wherein the channel associated with the shared AP is busy, and wherein the shared AP does not transmit the response frame.

Example 10: A wireless networking method, comprising: determining, by a sharing access point (AP) , that no shared AP is available for a multi-AP coordinated transmission; and abandoning, by the sharing AP, the multi-AP coordinated transmission.

Example 11: The method of example 10, wherein determining that no shared AP is available comprises receiving, by the sharing AP, no response frame from any shared AP within a specified period of time.

Example 12: The method of example 10 or 11, further comprising: restarting, by the sharing AP, a backoff process to contend for a channel; and performing, by the sharing AP, a non-coordinated transmission after successfully contending for the channel.

Example 13: An apparatus for wireless networking, comprising a processor and a memory including instructions stored thereon, wherein the instructions upon execution by the processor cause the processor to implement a method recited in any one or more of examples 1 to 12.

Example 14: A computer readable program storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited in any one or more of examples 1 to 12.

It will be appreciated by one of skill in the art that the present patent document discloses methods of performing, by a network device such as a sharing AP or a shared AP, a coordinated transmission that improves the efficiency of wireless networking. The present patent document specifies the details of the frame exchange process and when to abandon a coordinated transmission.

Some of the embodiments described herein are described in the general context of methods or processes, which may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM) , Random Access Memory (RAM) , compact discs (CDs) , digital versatile discs (DVD) , etc. Therefore, the computer-readable media can include a non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-or processor-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

Some of the disclosed embodiments can be implemented as devices or modules using hardware circuits, software, or combinations thereof. For example, a hardware circuit implementation can include discrete analog and/or digital components that are, for example, integrated as part of a printed circuit board. Alternatively, or additionally, the disclosed components or modules can be implemented as an Application Specific Integrated Circuit (ASIC) and/or as a Field Programmable Gate Array (FPGA) device. Some implementations may additionally or alternatively include a digital signal processor (DSP) that is a specialized microprocessor with an architecture optimized for the operational needs of digital signal processing associated with the disclosed functionalities of this application. Similarly, the various components or sub-components within each module may be implemented in software, hardware, or firmware. The connectivity between the modules and/or components within the modules may be provided using any one of the connectivity methods and media that is known in the art, including, but not limited to, communications over the Internet, wired, or wireless networks using the appropriate protocols.

While this document contains many specifics, these should not be construed as limitations on the scope of an invention that is claimed or of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination. Similarly, while operations are depicted in the drawings 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.

Only a few implementations and examples are described, and other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document.

Claims

A wireless networking method, comprising:

transmitting, by a sharing access point (AP) , a trigger frame associated with a multi-AP coordinated transmission;

receiving, by the sharing AP, a response frame indicating an idle status of a channel associated with a shared AP, wherein the sharing AP and the shared AP are included in a coordinated set; and

transmitting, by the sharing AP and in response to receiving the response frame, an instruction initiating the multi-AP coordinated transmission.
The method of claim 1, further comprising transmitting, by the sharing AP, a physical layer protocol data unit (PPDU) simultaneously with the shared AP in a coordinated mode.
The method of claim 1 or 2, wherein the trigger frame is a synchronization frame or a notification frame, and wherein the trigger frame comprises at least one of an identifier of the shared AP, a priority or a traffic identifier of a transmitted data, or an information necessary for the shared AP to reply with the response frame.
The method of claim 3, wherein the identifier of the shared AP is a medium access control (MAC) address or a unique identifier of the shared AP, wherein the priority or the traffic identifier of the transmitted data is used to identify a service flow or a quality of service (QoS) parameter associated with the transmitted data, wherein the information necessary for the shared AP to reply with the response frame comprises at least one of a physical layer protocol data unit (PPDU) format, a resource unit (RU) position, or a modulation and coding scheme (MCS) , and wherein the RU position helps avoid a conflict between the response frame and another response frame from another shared AP.
The method of any of claims 1-4, wherein the idle status of the channel associated with the shared AP is evaluated by a clear channel assessment (CCA) or by setting a network allocation vector (NAV) .
A wireless networking method, comprising:

receiving, by a shared access point (AP) , a trigger frame associated with a multi-AP coordinated transmission; and

determining, by the shared AP and based on a busy or idle status of a channel associated with the shared AP, whether to reply to the trigger frame with a response frame.
The method of claim 6, wherein the channel associated with the shared AP is idle, and wherein the shared AP transmits the response frame.
The method of claim 6 or 7, wherein the channel associated with the shared AP is idle, and wherein at least one of the following applies:

the response frame comprises a network allocation vector (NAV) duration that avoids a conflict with an upcoming coordinated transmission; or

a NAV duration is set to an entire transmit opportunity (TXOP) duration or a minimum duration required for one physical layer protocol data unit (PPDU) frame exchange sequence.
The method of claim 6, wherein the channel associated with the shared AP is busy, and wherein the shared AP does not transmit the response frame.
A wireless networking method, comprising:

determining, by a sharing access point (AP) , that no shared AP is available for a multi-AP coordinated transmission; and

abandoning, by the sharing AP, the multi-AP coordinated transmission.
The method of claim 10, wherein determining that no shared AP is available comprises receiving, by the sharing AP, no response frame from any shared AP within a specified period of time.
The method of claim 10 or 11, further comprising:

restarting, by the sharing AP, a backoff process to contend for a channel; and

performing, by the sharing AP, a non-coordinated transmission after successfully contending for the channel.
An apparatus for wireless networking, comprising a processor and a memory including instructions stored thereon, wherein the instructions upon execution by the processor cause the processor to implement a method recited in any one or more of claims 1 to 12.
A computer readable program storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited in any one or more of claims 1 to 12.