Patent Description:
The invention generally relates to coordinated-spatial reuse, in the following also referred to as CO-SR, technology, and more particularly, to a CO-SR transmission method and apparatus.

IEEE <NUM> is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) communication in the Wi-Fi (<NUM>, <NUM>, <NUM>, and <NUM>) frequency bands. The <NUM> family consists of a series of half-duplex over-the-air modulation techniques that use the same basic protocol. The standards and amendments provide the basis for wireless network products using the Wi-Fi frequency bands. For example, IEEE <NUM>. 11ac is a wireless networking standard in the IEEE <NUM> family providing high-throughput WLANs on the <NUM> band. Significantly wider channel bandwidths (<NUM>, <NUM>, <NUM>, and <NUM>) were proposed in the IEEE <NUM>. 11ac standard. The High Efficiency WLAN study group (HEW SG) is a study group within the IEEE <NUM> working group that will consider the improvement of spectrum efficiency to enhance the system throughput in high-density scenarios of wireless devices. Because of HEW SG, TGax (an IEEE task group) was formed and tasked to work on IEEE <NUM>. 11ax standard that will become a successor to IEEE <NUM>. Recently, WLAN has seen exponential growth across organizations in many industries.

Coordinated-spatial reuse, in the following also referred to as CO-SR, is an application of the potential Wi-Fi8 spatial reuse (SR) scheme under the multi-AP operation framework. The CO-SR transmission may joint power control and link adaptation among multiple APs to minimize spatial reuse caused negative impact and maximize total throughput among multi-APs.

In conventional CO-SR transmission, when the stations (STAs) in CO-SR RS transmission are legacy STAs, the BA frame from the STA associated with the shared AP may overlap with the next announcement frame from the sharing AP. As a result, the shared AP may not receive the next announcement frame from the sharing AP successfully to maintain the CO-SR transmission.

Therefore, how to avoid interference between the announcement frame from the sharing AP and the BA frame from the STA associated with the shared AP is a topic that is worthy of discussion.

<NUM> TGbe contribution <NUM>-<NUM>-<NUM>-<NUM>-00BE-SHARED-TXOP-SPATIAL-REUSE-CONSIDERATIONS discloses an example of the prior art.

Coordinated-spatial reuse, in the following also referred to as CO-SR, transmission methods and apparatus for CO-SR transmission are provided to overcome the problems mentioned above. A method and an apparatus according to the invention are defined in the independent claims. The dependent claims define preferred embodiments thereof.

An embodiment of the invention provides a CO-SR transmission method. In the CO-SR transmission method, a transceiver of a sharing access point (AP) may transmit an announcement frame to a shared AP, the transceiver may receive a first block acknowledgement (BA) frame from a first station (STA) associated with the sharing AP, and the transceiver may transmit a dummy clear-to-send (CTS) frame before transmitting the next announcement frame in response to the first STA being a first legacy STA.

An embodiment of the invention provides a CO-SR transmission method. In the CO-SR transmission method, a transceiver of a shared access point (AP) receives an announcement frame from a sharing AP, a processor of the shared AP shrinks the length of a data frame in response to a station (STA) associated with the shared AP being a legacy STA, the transceiver transmits the data frame to the STA, and the transceiver receives a block acknowledgement (BA) frame from the STA.

An embodiment of the invention provides apparatus for CO-SR transmission. The apparatus may include a transceiver and a processor. The transceiver may wirelessly communicate with a sharing access point (AP). The processor may be coupled to the transceiver. The transceiver receives an announcement frame from the sharing AP. The processor shrinks the length of the data frame in response to a station (STA) associated with the shared AP being a legacy STA, the transceiver transmits the data frame to the STA. The transceiver receives a block acknowledgement (BA) frame from the STA.

Other aspects and features of the invention will become apparent to those with ordinary skill in the art upon review of the following descriptions of specific embodiments of the CO-SR transmission method and apparatus for CO-SR transmission.

The invention will become more fully understood by referring to the following detailed description with reference to the accompanying drawings, wherein:.

<FIG> is a block diagram of a wireless communication network <NUM> according to an embodiment of the invention. As shown in <FIG>, the wireless network <NUM> may comprise a basic service set (BSS) <NUM> and a second BBS <NUM>. The first BSS may comprise an access point (AP) AP<NUM>, a station (STA) STA<NUM> and a station STA<NUM>. The second BSS may comprise an access point AP<NUM>, a station STA<NUM> and a station STA<NUM>. It should be noted that, in order to clarify the concept of the invention, <FIG> presents a simplified block diagram in which only the elements relevant to the invention are shown. However, the invention should not be limited to what is shown in <FIG>.

In an embodiment, the access points AP<NUM> and AP<NUM> may include wireless routers, access points, laptops, desktop computers, smart phones, tablet PCs, etc. In some embodiments, the access point AP1 may be regarded as a controller device which is connected to a WAN (wide area network) port of a modem device (not shown in FIG. 1A) through a backhaul link. In addition, it should be noted that, in order to illustrate the embodiments of the invention, the access point AP<NUM> may be regarded as a sharing AP and the access point AP<NUM> may be regarded as the shared AP in the coordinated-spatial reuse (CO-SR) transmission.

In an embodiment, each of the station STA<NUM>, station STA<NUM>, station STA<NUM> and station STA<NUM> may be a UE such as a portable or mobile apparatus, a wearable apparatus, a wireless communication apparatus or a computing apparatus. For example, STA may be implemented in a smartphone, a smartwatch, a personal digital assistant, a digital camera, or a computing equipment such as a tablet computer, a laptop computer or a notebook computer. In addition, in the embodiments, the station STA<NUM>, a station STA<NUM>, station STA<NUM> and a station STA<NUM> may be legacy STAs. The legacy STA may be high-throughput (HT) STA or very-high-throughput (VHT) STA. In addition, in the embodiments of the invention, the non-legacy STAs may be the STAs in Wi-Fi <NUM>, Wi-Fi <NUM>, or other newer Wi-Fi standards, e.g., the non-legacy STAs may be high-efficiency (HE) STAs or an extremely-high-throughput (EHT) STAs.

<FIG> is a block diagram of an access point <NUM> according to an embodiment of the invention. The access point <NUM> may be applied to the access point AP1 and the access point AP2. As shown in <FIG>, the access point <NUM> may include an integrated circuit <NUM>, processing circuit <NUM>, a memory <NUM>, and at least one antenna <NUM>. The antennas <NUM> may transmit and receive radio frequency (RF) signals. It should be noted that, in order to clarify the concept of the invention, <FIG> presents a simplified block diagram in which only the elements relevant to the invention are shown. However, the invention should not be limited to what is shown in <FIG>.

The integrated circuit <NUM> is coupled to the antennas <NUM>, and the integrated circuit <NUM> may include one or more transceivers <NUM> which may receive RF signal from the antennas <NUM>, convert them to baseband signals, and send the baseband signals to the processing circuit <NUM>. The transceivers <NUM> may also receive the baseband signals from the processing circuit <NUM>, convert them to RF signal, and send out the RF signals to antennas <NUM>. The transceivers <NUM> may comprise a plurality of hardware elements to perform radio frequency conversion. For example, the transceivers <NUM> may comprise a power amplifier, a mixer, an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC), but the invention should not be limited thereto.

In some embodiments, the integrated circuit <NUM> may be a Wi-Fi chip, and the integrated circuit <NUM> and the processing circuit <NUM> may be implemented by a system-on-chip (SoC), but the disclosure is not limited thereto.

In some embodiments, the processing circuit <NUM> may be implemented by a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), or a microcontroller, but the disclosure is not limited thereto. In the embodiments of the invention, the processing circuit <NUM> may control the operations of the integrated circuit <NUM> and the memory <NUM>. According to an embodiment of the invention, the processing circuit <NUM> may also be arranged to execute the program codes of the software modules. The program codes accompanied by specific data in a data structure may also be referred to as a processor logic unit or a stack instance when being executed. Therefore, the processing circuit <NUM> may be regarded as being comprised of a plurality of processor logic units, each for executing one or more specific functions or tasks of the corresponding software modules.

The memory <NUM> may be a volatile memory or a non-volatile memory. For example, the volatile memory may be a static random access memory (SRAM) or a dynamic random access memory (DRAM), and the non-volatile memory may be a flash memory, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM), but the disclosure is not limited thereto. In addition, the memory <NUM> may store instructions or firmware that can be executed by the processing circuit <NUM> to control operations of the access point <NUM>.

<FIG> is schematic diagrams illustrating CO-SR transmission for legacy STA according to an embodiment of the invention. As shown in <FIG>, the sharing AP (i.e., access point AP1) may transmit an announcement frame (e.g., Co-SR announcement frame) to the shared AP (i.e., access point AP2).

In the embodiments of the invention, the announcement frame may comprise information the shared AP Tx power control, Co-SR duration, shared AP's medium access control (MAC) address, and so on. In addition, the announcement frame may further comprise a sharing AP block acknowledgement (BA) type field and a sharing AP BA length. The sharing AP BA type may comprise legacy BA, trigger for BA and multi-user BA request (MU-BAR). The sharing AP BA type field may indicate the sharing AP BA type in the CO-SR transmission. For example, in <FIG>, the sharing AP BA type may be legacy BA, i.e., the STAs in the CO-SR transmission is legacy BAs (e.g., HT STAs or VHT STAs). In another example, in <FIG>, the sharing AP BA type may be trigger for BA. In another example, in <FIG>, the sharing AP BA type may be MU-BAR. The sharing AP BA length field may indicate the BA length in the CO-SR transmission.

After the shared AP receives the announcement frame, the shared AP and the sharing AP may each perform downlink data transmission. The sharing AP may transmit a first data frame to a STA associated with the sharing AP (taking the station STA<NUM> as an example in <FIG>), and the shared AP may transmit a second data frame to a STA associated with the shared AP (taking the station STA<NUM> as an example in <FIG>). As shown in <FIG>, in the embodiment, transmission of the first data frame and transmission of the second data frame may end simultaneously, i.e., the tail of the second data frame is aligned to the tail of the first data frame. In the embodiment, the first data frame and second data frame may be aggregated MAC protocol data unit (A-MPDU).

After the transmission of the first data frame and the second data frame, the station STA<NUM> associated with the sharing AP may transmit a first BA frame BA1 to the sharing AP, and the station STA<NUM> associated with the shared AP may transmit a second BA frame BA2 to the shared AP. The transmission rate of the station STA<NUM> and station STA<NUM> may be different. As a result, when the station STA<NUM> and station STA<NUM> are legacy stations (e.g., HT STAs or VHT STAs) and the BA duration of the second BA frame BA2 is too long, the second BA frame BA2 from the station STA<NUM> may overlap with the next announcement frame from the sharing AP. Therefore, in the embodiment, the sharing AP may transmit dummy clear-to-send (CTS) frame before transmitting the next announcement frame to avoid the interference between the second BA frame BA2 and the next announcement frame. The sharing AP may transmit the dummy CTS frame after a frame space (e.g., a short inter-frame space (SIFS)) between the first BA frame BA1 and the dummy CTS frame. The total length of the length of the first BA frame BA1, the length of the frame space and the length of the dummy CTS frame may be longer than the length of the second BA frame BA2. For example, if the length of the first BA frame BA1 is <NUM>, the length of the second BA frame BA2 is <NUM>, and the length of the frame space is <NUM>, the length of the dummy CTS frame may be set to <NUM> (i.e., <NUM>+<NUM>+<NUM>><NUM>).

<FIG> is schematic diagrams illustrating CO-SR transmission for legacy STA according to another embodiment of the invention. As shown in <FIG>, the sharing AP (i.e., access point AP1) may transmit an announcement frame (e.g., Co-SR announcement frame) to the shared AP (i.e., access point AP2).

After the shared AP receives the announcement frame, the shared AP and the sharing AP may each perform downlink data transmission. The sharing AP may transmit a first data frame to a STA associated with the sharing AP (taking the station STA<NUM> as an example in <FIG>), and the shared AP may transmit a second data frame to a STA associated with the shared AP (taking the station STA<NUM> as an example in <FIG>). In the embodiment, the first data frame and second data frame may be A-MPDU. As shown in <FIG>, in the embodiment, the shared AP may shrink the length (i.e., the transmission duration) of the second data frame by default length. For example, the shared AP may shrink the length of the second data frame by <NUM> (i.e., the default length). Specifically, in conventional CO-SR transmission for legacy STA, the tail of the second data frame is aligned to the tail of the first data frame. However, in the embodiment, as shown in <FIG>, the shared AP may shrink the length of the second data frame to avoid the second BA frame BA2 from the station STA<NUM> associated with the shared AP overlap with the next announcement frame from the sharing AP.

After the transmission of the first data frame and the second data frame, the station STA<NUM> associated with the sharing AP may transmit the first BA frame BA1 to the sharing AP, and the station STA<NUM> associated with the shared AP may transmit the second BA frame BA2 to the shared AP. In the embodiment, even if the BA duration (e.g., <NUM>) of the second BA frame BA2 is longer than the BA duration (e.g., <NUM>) of the first BA frame BA1, the second BA frame BA2 will not overlap with the next announcement frame from the sharing AP.

After the shared AP receives the announcement frame, the shared AP and the sharing AP may each perform downlink data transmission. The sharing AP may transmit a first data frame to a STA associated with the sharing AP (taking the station STA<NUM> as an example in <FIG>), and the shared AP may transmit a second data frame to a STA associated with the shared AP (taking the station STA<NUM> as an example in <FIG>). In the embodiment, the first data frame and second data frame may be A-MPDU. As shown in <FIG>, in the embodiment, the shared AP may shrink or adjust the length of the second data frame to make the tail of the second BA frame BA2 is aligned with the tail of the first data frame. Specifically, the shared AP may estimate the length of the second BA frame BA2 based on a look-up table. The look-up table may record that the relationship between the transmission rates of the station STA<NUM> and the lengths of the second BA frame BA2, e.g., look-up table may record that the transmission rate 24Mbps is corresponded to length <NUM> , the transmission rate 12Mbps is corresponded to length <NUM> and the transmission rate 6Mbps is corresponded to length <NUM>. Because the transmission rate of the STA associated with the shared AP is usually the same as the transmission rate of the shared AP, the shared AP may estimate the length of the second BA frame BA2 based on its transmission rate (i.e., the transmission rate of the shared AP) and the look-up table. After the shared AP has estimated the length of the second BA frame BA2, the may shrink or adjust the length of the second data frame based on the estimated length of the second BA frame BA2 to make the tail of the second BA frame BA2 is aligned with the tail of the first data frame. For example, as shown in <FIG>, the shared AP may shrink the length of the second data frame based on the estimated length (<NUM>) of the second BA frame BA2. It should be noted that in <FIG>, the estimated length of the second BA frame BA2 is <NUM>, but the invention should not be limited thereto.

After the transmission of the first data frame and the second data frame, the station STA<NUM> associated with the sharing AP may transmit the first BA frame BA1 to the sharing AP, and the station STA<NUM> associated with the shared AP may transmit the second BA frame BA2 to the shared AP. In the embodiment, because the tail of the second BA frame BA2 is aligned with the tail of the first data frame, the second BA frame BA2 will not overlap with the next announcement frame from the sharing AP.

<FIG> is schematic diagrams illustrating CO-SR transmission for non-legacy STA (e.g., HE STA or EHT STA) according to an embodiment of the invention. As shown in <FIG>, the sharing AP (i.e., access point AP1) may transmit an announcement frame (e.g., Co-SR announcement frame) to the shared AP (i.e., access point AP2). The announcement frame may comprise a trigger-based (TB) BA length.

After the shared AP receives the announcement frame, the shared AP and the sharing AP may each perform downlink data transmission. The sharing AP may transmit a first data frame to a STA associated with the sharing AP (taking the station STA<NUM> as an example in <FIG>), and the shared AP may transmit a second data frame to a STA associated with the shared AP (taking the station STA<NUM> as an example in <FIG>). In the embodiment, the first data frame and second data frame may be A-MPDU. As shown in <FIG>, in the embodiment, the first data frame and the second data frame may comprise a trigger frame. The trigger frame may indicate the transmission rates and lengths of the first BA frame BA1 and the second BA frame BA2. That is, in the embodiment, the sharing AP BA type is trigger for BA, and the first BA frame BA1 and the second BA frame BA2 are trigger-based (TB) BAs triggered by trigger frame.

After the transmission of the first data frame and the second data frame, the station STA<NUM> associated with the sharing AP may transmit the first BA frame BA1 to the sharing AP, and the station STA<NUM> associated with the shared AP may transmit the second BA frame BA2 to the shared AP.

<FIG> is schematic diagrams illustrating CO-SR transmission for non-legacy STA (e.g., HE STA or EHT STA) according to another embodiment of the invention. As shown in <FIG>, the sharing AP (i.e., access point AP1) may transmit an announcement frame (e.g., Co-SR announcement frame) to the shared AP (i.e., access point AP2). The announcement frame may comprise a trigger-based (TB) BA length.

After the shared AP receives the announcement frame, the shared AP and the sharing AP may each perform downlink data transmission. The sharing AP may transmit a first data frame to a STA associated with the sharing AP (taking the station STA<NUM> as an example in <FIG>), and the shared AP may transmit a second data frame to a STA associated with the shared AP (taking the station STA<NUM> as an example in <FIG>). In the embodiment, the first data frame and second data frame may be A-MPDU.

As shown in <FIG>, in the embodiment, after the sharing AP transmits the first data frame to the station STA<NUM> and the shared AP transmits the second data frame to the station STA<NUM>, the sharing AP may transmit a multi-user BA request (MU-BAR) frame to the station STA<NUM> and the shared AP may also transmits a MU-BAR frame to the station STA<NUM>. The MU-BAR frame may indicate the transmission rates and lengths of the first BA frame BA1 and the second BA frame BA2. That is, in the embodiment, the sharing AP BA type is MU-BAR, and the first BA frame BA1 and the second BA frame BA2 are trigger-based (TB) BAs triggered by MU-BAR frame.

<FIG> is a flow chart illustrating a CO-SR transmission method according to an embodiment of the invention. The CO-SR transmission method can be applied to the wireless communication network <NUM> and AP <NUM>. In addition, the CO-SR transmission method is applied to a sharing AP in the CO-SR transmission. As shown in <FIG>, in step S810, a sharing AP may transmit an announcement frame to a shared AP.

In step S820, the sharing AP may receive a first BA frame from a first STA associated with the sharing AP.

In step S830, in response to the first STA being a first legacy STA, the sharing AP may transmit a dummy clear-to-send (CTS) frame before transmitting the next announcement frame.

In the CO-SR transmission method, the sharing AP may further transmit the dummy CTS frame after a frame space between the first BA frame and the dummy CTS frame. The total length of the first length of the first BA frame, the second length of the frame space and the third length of the dummy CTS frame is longer than the fourth length of the second BA frame. The second BA frame is transmitted to the shared AP by a second STA associated with the shared AP, and the second STA is a second legacy STA. The first legacy STA and the second legacy STA are HT STAs or VHT STAs.

In the CO-SR transmission method, the sharing AP may further transmit a data frame with a trigger frame to the first STA in response to the first STA is a HE STA or an EHT STA, and receive a trigger-based BA from the first STA.

In the CO-SR transmission method, the sharing AP may further transmit a multi-user BA request (MU-BAR) frame to the first STA in response to the first STA is a HE STA or an EHT STA, and receive a trigger-based BA from the first STA.

In the CO-SR transmission method, the announcement frame may comprise a sharing AP BA type field and a sharing AP BA length field.

<FIG> is a flow chart illustrating a CO-SR transmission method according to another embodiment of the invention. The CO-SR transmission method can be applied to the wireless communication network <NUM> and AP <NUM>. In addition, the-CO-SR RS transmission method is applied to a shared AP in the CO-SR transmission. As shown in <FIG>, in step S910, a shared AP may receive an announcement frame to a sharing AP.

In step S920, the shared AP may shrink the length of the data frame in response to a STA associated with the shared AP being a legacy STA.

In step S930, the shared AP may transmit the shrunk data frame to the STA.

In step S940, the shared AP may receive a BA frame from the STA.

In the CO-SR transmission method, the shared AP may further shrink the length of the data frame by a default length (e.g., <NUM>).

In the CO-SR transmission method, the shared AP may further estimate the length of the BA frame based on a look-up table, and shrink the length of the data frame based on the length of the BA frame. In the embodiment, a tail of the BA frame is aligned with a tail of data frame transmitted by the sharing AP.

In the CO-SR transmission method, the legacy STA may a HT STA or a VHT STA.

In the CO-SR transmission method, the shared AP may further transmit a data frame with a trigger frame to the STA in response to the STA being a HE STA or an EHT STA, and receive a trigger-based BA from the STA.

In the CO-SR transmission method, the shared AP may further transmit a MU-BAR frame to the STA in response to the STA being a HE STA or an EHT STA, and receive a trigger-based BA from the STA.

In the CO-SR transmission methods provided in the invention, when the STA is legacy STA, it will be avoided that the BA frame from the STA associated with the shared AP may overlap with the next announcement frame from the sharing AP.

Use of ordinal terms such as "first", "second", "third", etc., in the disclosure and claims is for description. It does not by itself connote any order or relationship.

The steps of the method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module (e.g., including executable instructions and related data) and other data may reside in a data memory such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium known in the art. A sample storage medium may be coupled to a machine such as, for example, a computer/processor (which may be referred to herein, for convenience, as a "processor") such that the processor can read information (e.g., code) from and write information to the storage medium. A sample storage medium may be integral to the processor. The ASIC may reside in the UE. In the alternative, the processor and the storage medium may reside as discrete components in the UE. Moreover, in some aspects, any suitable computer-program product may comprise a computer-readable medium comprising codes relating to one or more of the aspects of the disclosure. In some aspects, a computer software product may comprise packaging materials.

It should be noted that although not explicitly specified, one or more steps of the methods described herein can include a step for storing, displaying and/or outputting as required for a particular application. In other words, any data, records, fields, and/or intermediate results discussed in the methods can be stored, displayed, and/or output to another device as required for a particular application. While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention can be devised without departing from the basic scope thereof. Various embodiments presented herein, or portions thereof, can be combined to create further embodiments. The above description is of the best-contemplated mode of carrying out the invention.

The above paragraphs describe many aspects. Obviously, the teaching of the invention can be accomplished by many methods, and any specific configurations or functions in the disclosed embodiments only present a representative condition. Those who are skilled in this technology will understand that all of the disclosed aspects in the invention can be applied independently or be incorporated.

Claim 1:
A coordinated-spatial reuse, in the following also referred to as CO-SR, transmission method, comprising:
transmitting (S810), by a transceiver of a sharing access point, AP, an announcement frame to a shared AP;
receiving (S820), by the transceiver, a first block acknowledgement, BA, frame from a first station, STA,
associated with the sharing AP; and
transmitting (S830), by the transceiver, a dummy clear-to-send, CTS, frame before transmitting a next announcement frame in response to the first STA being a first legacy STA.