Cooperative multi-user transmission with multiple access points

Abstract

To provide a method and a master access point (AP) that enable coordination of multiple access points in multiple wireless local area networks.SOLUTION: In a method, a master AP, which is associated with one or more first client stations, generates an announcement frame that announces coordinated multi-user (MU) transmission involving multiple APs including the master AP and one or more slave APs. Each of the slave APs is associated with respective one or more second client stations. The announcement frame is generated to indicate respective one or more frequency resource units (RUs) allocated to the one or more slave APs for the coordinated MU transmission. The master AP transmits the announcement frame to the one or more slave APs to initiate the coordinated MU transmission and participates in the coordinated MU transmission, while the one or more slave APs also participate in the coordinated MU transmission.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 821,936, entitled "Access Point (AP) Coordinated Orthogonal Frequency Multiple Access (OFDMA)," filed March 21, 2019, U.S. Provisional Patent Application No. 62 / 837,106, entitled "Access Point (AP) Coordinated Orthogonal Frequency Multiple Access (OFDMA)," filed April 22, 2019, and U.S. Provisional Patent Application No. 62 / 934,452, entitled "Access Point (AP) Coordinated Orthogonal Frequency Multiple Access (OFDMA)," filed November 12, 2019. All of the above-referenced applications are incorporated herein by reference in their entirety.

[0002] TECHNICAL FIELD The present disclosure relates generally to wireless communication systems, and more particularly to cooperation of multiple access points in multiple wireless local area networks. [Background technology]

[0003] Wireless local area networks (WLANs) have evolved rapidly over the past two decades, with the development of WLAN standards such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards increasing single-user peak data rates. One means of increasing data rates is to increase the frequency bandwidth of the communication channel used in the WLAN. For example, the IEEE 802.11n standard allows for the aggregation of two 20 MHz subchannels to form a 40 MHz aggregate communication channel, and the more recent IEEE 802.11ax standard allows for the aggregation of up to eight 20 MHz subchannels to form an aggregate communication channel of up to 160 MHz. Work is currently underway on a new iteration of the IEEE 802.11 standard, referred to as the IEEE 802.11be standard, or Extremely High Throughput (EHT) WLAN. The IEEE 802.11be standard allows for the aggregation of as many as sixteen 20 MHz sub-channels (or potentially even more) to form a 320 MHz aggregate communications channel (or potentially even wider aggregate communications channel).

[0004] As the density of IEEE 802.11 WLANs increases over time, it tends to become more difficult for access points (APs) to find idle 20 MHz subchannels that can be aggregated together to form a larger aggregate channel. One means of increasing the likelihood that WLANs can utilize wider frequency bandwidth is to allow APs in neighboring networks to coordinate subchannel use among WLANs. Summary of the Invention

[0005] In one embodiment, a method for wireless communication by a first access point (AP) associated with one or more first client stations includes generating an announcement frame at the first AP announcing a cooperative multi-user (MU) transmission involving multiple APs, including the first AP and one or more second APs, each of the second APs being associated with a respective one or more second client stations, the announcement frame being generated to indicate a respective one or more frequency resource units (RUs) allocated to the one or more second APs for the cooperative MU transmission; transmitting the announcement frame by the first AP to the one or more second APs to initiate the cooperative MU transmission; and engaging in the cooperative MU transmission by the first AP, while the one or more second APs also engage in the cooperative MU transmission.

[0006] In another embodiment, a first AP associated with one or more first client stations comprises a wireless network interface device including one or more integrated circuit (IC) devices, the one or more IC devices configured to: generate an announcement frame announcing a cooperative MU transmission involving multiple APs, including the first AP and one or more second APs, each of the second APs associated with a respective one or more second client stations, the announcement frame being generated to indicate a respective one or more frequency RUs assigned to the one or more second APs for the cooperative MU transmission; control the wireless network interface device to send the announcement frame to the one or more second APs to initiate the cooperative MU transmission; and control the wireless network interface device to engage in the cooperative MU transmission, while the one or more second APs also engage in the cooperative MU transmission.

[0007] In yet another embodiment, a method for wireless communication by a first AP associated with one or more first client stations includes receiving, at the first AP, an announcement frame from a second AP associated with one or more second client stations, the announcement frame announcing a cooperative MU transmission involving at least the first AP and the second AP, the announcement frame including an indicator of a frequency RU assigned to the first AP for the cooperative MU transmission; and engaging in the cooperative MU transmission by the first AP using the frequency RU indicated by the announcement frame, while the second AP also engages in the cooperative MU transmission.

[0008] In yet another embodiment, a first AP is associated with one or more first client stations, the first AP including a wireless network interface device including one or more IC devices, the one or more IC devices configured to: receive an announcement frame from a second AP associated with one or more second client stations, the announcement frame announcing a cooperative MU transmission involving at least the first AP and the second AP, the announcement frame including an indicator of a frequency RU assigned to the first AP for the cooperative MU transmission; and control the wireless network interface device to engage in the cooperative MU transmission using the frequency RU indicated by the announcement frame, while the second AP also engages in the cooperative MU transmission. [Brief explanation of the drawings]

[0009] [Figure 1A] 1 is a block diagram of an exemplary communication system including multiple access points (APs) engaged in cooperative multi-user (MU) transmissions, according to one embodiment.

[0010] [Figure 1B] 1B is a block diagram of an exemplary AP in the communication system of FIG. 1A according to one embodiment.

[0011] [Figure 1C] 1B is a block diagram of an exemplary client station in the communication system of FIG. 1A, according to one embodiment.

[0012] [Figure 2] 1B is a diagram of an exemplary cooperative MU downlink (DL) transmission implemented by the communication system of FIG. 1A, according to one embodiment.

[0013] [Figure 3] 1B is a diagram of another example cooperative MU DL transmission implemented by the communication system of FIG. 1A according to another embodiment.

[0014] [Figure 4] 1B is a diagram of another example cooperative MU DL transmission implemented by the communication system of FIG. 1A according to another embodiment.

[0015] [Figure 5] 5 is a diagram of an exemplary acknowledgement procedure used in a cooperative MU DL transmission such as in FIGS. 2-4, according to one embodiment.

[0016] [Figure 6] FIG. 5 is a diagram of another exemplary acknowledgement procedure used in cooperative MU DL transmission, such as in FIGS. 2-4, according to another embodiment.

[0017] [Figure 7] FIG. 5 is a diagram of another exemplary acknowledgement procedure used in cooperative MU DL transmission, such as in FIGS. 2-4, according to another embodiment.

[0018] [Figure 8] 1B is a diagram of an exemplary cooperative MU uplink (UL) transmission implemented by the communication system of FIG. 1A, according to one embodiment.

[0019] [Figure 9]1B is a diagram of another exemplary cooperative MU UL transmission implemented by the communication system of FIG. 1A according to another embodiment.

[0020] [Figure 10] 1B is a diagram of another exemplary cooperative MU UL transmission implemented by the communication system of FIG. 1A according to another embodiment.

[0021] [Figure 11] 11 is a diagram of an exemplary acknowledgement procedure used in cooperative MU UL transmissions, such as in FIGS. 8-10, according to one embodiment.

[0022] [Figure 12] 1 is a diagram of an exemplary cooperative MU UL transmission followed by a cooperative MU DL transmission according to one embodiment.

[0023] [Figure 13] 1 is a diagram of an exemplary cooperative MU DL transmission followed by a cooperative MU UL transmission according to one embodiment.

[0024] [Figure 14] 1 is a flow diagram of an exemplary method for cooperative wireless communication involving multiple APs, according to one embodiment.

[0025] [Figure 15] 10 is a flow diagram of another exemplary method for cooperative wireless communication involving multiple APs, according to another embodiment.

[0026] [Figure 16] 10 is a flow diagram of another exemplary method for cooperative wireless communication involving multiple APs, according to another embodiment.

[0027] [Figure 17] 10 is a flow diagram of another exemplary method for cooperative wireless communication involving multiple APs, according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] In various embodiments described below, access points (APs) of neighboring wireless local area networks (WLANs) coordinate the use of radio subchannels. For example, one AP may act as a "master AP," and one or more other APs may act as "slave APs," and the master AP may coordinate synchronized transmissions in each WLAN, the synchronized transmissions using respective frequency segments. Such synchronized transmissions are sometimes referred to as cooperative orthogonal frequency division multiple access (C-OFDMA).

[0029] According to some embodiments, as part of coordinating a C-OFDMA transmission, the master AP generates and transmits a C-OFDMA announcement (C-OFDMA-A) frame to one or more slave APs. According to one embodiment, the C-OFDMA-A frame announces the start of a coordinated uplink or downlink OFDMA transmission involving multiple WLANs. According to various embodiments, the C-OFDMA-A frame includes information about the coordinated OFDMA transmission, such as one or any suitable combination of two or more of: i) the respective frequency bandwidths used in each WLAN; ii) the respective frequency resource units (RUs) used in each WLAN; iii) the duration (hours) of the coordinated OFDMA transmission; and iv) the respective lengths (e.g., bits, octets, words, etc.) of each OFDMA transmission in each WLAN.

[0030] According to some embodiments, for C-OFDMA downlink (DL) transmissions, the C-OFDMA-A frame transmitted by the master AP prompts one or more slave APs to transmit respective DL OFDMA transmissions as part of the C-OFDMA transmission. According to some embodiments, for C-OFDMA uplink (UL) transmissions, the C-OFDMA-A frame transmitted by the master AP prompts one or more slave APs to transmit respective trigger frames, thereby prompting respective sets of client stations to transmit respective UL OFDMA transmissions as part of the C-OFDMA transmission.

[0031] 1A is a diagram of an exemplary communication system 10 including multiple WLANs, including WLAN 20 and WLAN 30. Although two WLANs are shown in FIG. 1A, communication system 10 may include other suitable numbers of WLANs, such as three, four, five, etc., in various embodiments.

[0032] The WLAN 20 includes an AP 34 and multiple client stations 38. As described in more detail below, the AP 34 acts as a master AP in each WLAN, coordinating synchronized transmissions. For example, according to some embodiments, the master AP 34 transmits instructions, information, etc. regarding C-OFDMA transmissions to one or more slave APs.

[0033] The WLAN 30 includes an AP 44 and multiple client stations 48. The AP 44 operates as a slave AP that participates in C-OFDMA transmissions coordinated by the master AP 34. For example, in some embodiments, the slave AP 44 receives instructions, information, etc. regarding the C-OFDMA transmissions from the master AP 34, and the slave AP 44 participates in the C-OFDMA transmissions in accordance with the instructions, information, etc. received from the master AP 34.

[0034] According to various embodiments, the master AP 34 includes a C-OFDMA controller 60 that determines parameters of the C-OFDMA transmission, generates data units for setting up the C-OFDMA transmission, controls the timing of transmissions by the master AP 34 during the C-OFDMA transmission, etc. The C-OFDMA controller 60 is described in more detail below.

[0035] According to various embodiments, the slave AP 44 includes a C-OFDMA controller 70 that receives parameters for the C-OFDMA transmission from the master AP, generates data units for the C-OFDMA transmission, controls the timing of transmissions by the slave AP 44 during the C-OFDMA transmission, etc. The C-OFDMA controller 70 is described in more detail below.

[0036] In some embodiments, one or more client stations 38, 48 include a C-OFDMA controller 80 that, according to various embodiments, receives frames transmitted by the master AP 34 and / or slave AP 44 as part of setting up a C-OFDMA transmission (or by another AP (not shown) as part of setting up another C-OFDMA transmission in another set of WLANs (not shown)) and uses information in such frames for purposes such as determining whether the communication medium is idle. The C-OFDMA controller 80 is described in more detail below.

[0037] 1B is a block diagram of an exemplary AP 114 that can be used as the master AP 34 and / or the slave AP 44 according to various embodiments. In some embodiments, the AP 114 is configured to operate as the master AP at some times and as the slave AP at other times. The master AP typically assigns frequency resource units (RUs) and / or spatial streams, etc., to the slave AP for C-OFDMA transmission and initiates the C-OFDMA transmission. On the other hand, the slave AP typically engages in C-OFDMA transmission in response to a prompt from the master AP and uses the RUs and / or one or more spatial streams for C-OFDMA transmission assigned to the slave AP by the master AP.

[0038] The AP 114 includes a host processor 118 coupled to a wireless network interface device 122. The wireless network interface device 122 includes one or more medium access control (MAC) processors 126 (for brevity, sometimes referred to herein as “MAC processors 126”) and one or more physical layer (PHY) processors 130 (for brevity, sometimes referred to herein as “PHY processors 130”). The PHY processors 130 include multiple transceivers 134, which are coupled to multiple antennas 138. Although three transceivers 134 and three antennas 138 are shown in FIG. 1B, in other embodiments, the AP 114 includes other suitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers 134 and antennas 138. In some embodiments, the AP 114 includes more antennas 138 than transceivers 134, and antenna switching techniques are utilized.

[0039] The wireless network interface device 122 is implemented using one or more integrated circuit ICs configured to operate as discussed below. For example, the MAC processor 126 may be implemented at least partially on a first IC, and the PHY processor 130 may be implemented at least partially on a second IC. As another example, at least a portion of the MAC processor 126 and at least a portion of the PHY processor 130 may be implemented on a single IC. For example, the wireless network interface device 122 may be implemented using a system on a chip (SoC), where the SoC includes at least a portion of the MAC processor 126 and at least a portion of the PHY processor 130.

[0040] In one embodiment, host processor 118 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown), such as random access memory (RAM), read-only memory (ROM), flash memory, etc. In one embodiment, host processor 118 may be implemented at least partially on a first IC, and wireless network interface device 122 may be implemented at least partially on a second IC. As another example, host processor 118 and at least a portion of wireless network interface device 122 may be implemented on a single IC.

[0041] In various embodiments, the MAC processor 126 and / or the PHY processor 130 of the AP 114 are configured to generate data units and process received data units, the data units conforming to a WLAN communication protocol. For example, the MAC processor 126 is configured to implement MAC layer functions, including MAC layer functions, of the WLAN communication protocol, and the PHY processor 130 is configured to implement PHY functions, including PHY functions of the WLAN communication protocol. According to some embodiments, for example, the MAC processor 126 is configured to generate MAC layer data units, such as MAC service data units (MSDUs), MAC protocol data units (MPDUs), etc., and provide the MAC layer data units to the PHY processor 130. According to some embodiments, the PHY processor 130 is configured to receive the MAC layer data units from the MAC processor 126 and encapsulate the MAC layer data units to generate PHY data units, such as PHY protocol data units (PPDUs), for transmission via the antenna 138. Similarly, according to some embodiments, PHY processor 130 is configured to receive PHY data units received via antenna 138 and extract MAC layer data units encapsulated within the PHY data units. According to some embodiments, PHY processor 130 provides the extracted MAC layer data units to MAC processor 126, which processes the MAC layer data units.

[0042] A PHY data unit may be referred to herein as a "packet," and a MAC layer data unit may be referred to herein as a "frame."

[0043] According to one embodiment, in connection with generating one or more RF signals for transmission, PHY processor 130 is configured to process (which may include modulating, filtering, etc.) data corresponding to the PPDUs to generate one or more digital baseband signals and convert the digital baseband signals to one or more analog baseband signals. Additionally, PHY processor 130 is configured to upconvert the one or more analog baseband signals to one or more RF signals for transmission via one or more antennas 138.

[0044] In response to receiving one or more RF signals, PHY processor 130 is configured to downconvert the one or more RF signals to one or more analog baseband signals and convert the one or more analog baseband signals to one or more digital baseband signals. PHY processor 130 is further configured to process (which may include demodulating, filtering, etc.) the one or more digital baseband signals to generate a PPDU.

[0045] The PHY processor 130 may include an amplifier (e.g., a low noise amplifier (LNA), a power amplifier, etc.), an RF downconverter, an RF upconverter, multiple filters, one or more analog-to-digital converters (ADCs), one or more digital-to-analog converters (DACs), one or more discrete Fourier transform (DFT) calculators (e.g., fast Fourier transform (FFT) calculators), one or more inverse discrete Fourier transform (IDFT) calculators (e.g., inverse fast Fourier transform (IFFT) calculators), one or more modulators, one or more demodulators, etc., which are not shown in FIG. 1B for purposes of simplicity.

[0046] PHY processor 130 is configured to generate one or more RF signals that are provided to one or more antennas 138. PHY processor 130 is also configured to receive one or more RF signals from one or more antennas 138.

[0047] According to some embodiments, MAC processor 126 is configured to control PHY processor 130 to generate one or more RF signals, for example, by providing one or more MAC layer data units (e.g., MPDUs) to PHY processor 130 and optionally providing one or more control signals to PHY processor 130. In one embodiment, MAC processor 126 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown), such as RAM, read ROM, flash memory, etc. In another embodiment, MAC processor 126 includes a hardware state machine.

[0048] 1A and / or C-OFDMA controller 70. In some embodiments, as described in more detail below, C-OFDMA controller 60 is configured to generate C-OFDMA-A frames and prompt PHY processor 130 to transmit the C-OFDMA-A frames. In some embodiments, as described in more detail below, C-OFDMA controller 70 is configured to receive C-OFDMA-A frames from another AP and process the C-OFDMA frames.

[0049] 1C is a block diagram of an exemplary client station 154 that may be used as one or more of the client stations 38 / 48 of FIG. 1A, according to various embodiments. In other embodiments, one or more of the client stations 38 / 48 have a different suitable structure than the client station 154. For example, one or more of the client stations 38 / 48 are legacy client stations that do not include the C-OFDMA controller 80 of FIG. 1A.

[0050] The client station 154 includes a host processor 158 coupled to a network interface device 162. The network interface device 162 includes one or more MAC processors 166 (for brevity, sometimes referred to herein as “MAC processors 166”) and one or more PHY processors 170 (for brevity, sometimes referred to herein as “PHY processors 170”). The PHY processors 170 include multiple transceivers 174, which are coupled to multiple antennas 178. Although three transceivers 174 and three antennas 178 are shown in FIG. 1C , in other embodiments, the client station 154 includes other suitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers 174 and antennas 178. In some embodiments, the client station 154 includes more antennas 178 than transceivers 174, and antenna switching techniques are utilized.

[0051] Network interface device 162 may be implemented using one or more ICs configured to operate as discussed below. For example, MAC processor 166 may be implemented on at least a first IC, and PHY processor 170 may be implemented on at least a second IC. As another example, at least a portion of MAC processor 166 and at least a portion of PHY processor 170 may be implemented on a single IC. For example, network interface device 162 may be implemented using an SoC, where the SoC includes at least a portion of MAC processor 166 and at least a portion of PHY processor 170.

[0052] In one embodiment, host processor 158 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown), such as RAM, ROM, flash memory, etc. In one embodiment, host processor 158 may be implemented at least partially on a first IC, and network device 162 may be implemented at least partially on a second IC. As another example, host processor 158 and at least a portion of network interface device 162 may be implemented on a single IC.

[0053] In various embodiments, MAC processor 166 and PHY processor 170 of client station 154 are configured to generate data units and process received data units, the data units conforming to a WLAN communication protocol or another suitable communication protocol. For example, MAC processor 166 is configured to implement MAC layer functions, including MAC layer functions of the WLAN communication protocol, and PHY processor 170 is configured to implement PHY functions, including PHY functions of the WLAN communication protocol. According to some embodiments, MAC processor 166 is configured to generate MAC layer data units, such as MSDUs and MPDUs, and provide the MAC layer data units to PHY processor 170. According to some embodiments, PHY processor 170 is configured to receive MAC layer data units from MAC processor 166 and encapsulate the MAC layer data units to generate PHY data units, such as PPDUs, for transmission via antenna 178. Similarly, according to some embodiments, PHY processor 170 is configured to receive PHY data units received via antenna 178 and extract the MAC layer data units encapsulated within the PHY data units. According to some embodiments, the PHY processor 170 provides the extracted MAC layer data units to the MAC processor 166, which processes the MAC layer data units.

[0054] In one embodiment, PHY processor 170 is configured to downconvert one or more RF signals received via one or more antennas 178 to one or more baseband analog signals and convert the analog baseband signals to one or more digital baseband signals. PHY processor 170 is further configured to process the one or more digital baseband signals and demodulate the one or more digital baseband signals to generate PPDUs. PHY processor 170 may include an amplifier (e.g., an LNA, a power amplifier, etc.), an RF downconverter, an RF upconverter, multiple filters, one or more ADCs, one or more DACs, one or more DFT calculators (e.g., FFT calculators), one or more IDFT calculators (e.g., IFFT calculators), one or more modulators, one or more demodulators, etc., which are not shown in FIG. 1C for the sake of brevity.

[0055] PHY processor 170 is configured to generate one or more RF signals that are provided to one or more antennas 178. PHY processor 170 is also configured to receive one or more RF signals from one or more antennas 178.

[0056] According to some embodiments, MAC processor 166 is configured to control PHY processor 170 to generate one or more RF signals, for example, by providing one or more MAC layer data units (e.g., MPDUs) to PHY processor 170 and optionally providing one or more control signals to PHY processor 170. In one embodiment, MAC processor 166 includes a processor (not shown) configured to execute machine-readable instructions stored in a memory device (not shown), such as RAM, ROM, flash memory, etc. In one embodiment, MAC processor 166 includes a hardware state machine (not shown).

[0057] MAC processor 166 includes C-OFDMA controller 80 of Figure 1A. In some embodiments, C-OFDMA controller 80 is configured to receive frames transmitted as part of setting up a C-OFDMA transmission and to use information in such frames for purposes such as determining whether the communication medium is idle, according to various embodiments.

[0058] Figure 2 is a diagram of an exemplary C-OFDMA DL packet exchange 200 in a communication system such as communication system 10 of Figure 1A or another suitable communication system, according to one embodiment. Figure 2 is described with reference to Figures 1A-1C for illustrative purposes. However, in some embodiments, C-OFDMA DL packet exchange 200 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0059] A master AP (e.g., master AP 34) generates and transmits a C-OFDMA-A frame 204 to one or more slave APs (e.g., slave AP 44). The C-OFDMA-A frame, according to one embodiment, announces the start of a DL C-OFDMA transmission involving multiple WLANs. According to various embodiments, the C-OFDMA-A frame 204 includes information about the DL C-OFDMA transmission, such as one or any suitable combination of: i) an indicator of one or more WLANs involved in the DL C-OFDMA transmission; ii) the respective frequency bandwidths used in each WLAN for the DL C-OFDMA transmission; iii) the respective frequency RUs used in each WLAN for the DL C-OFDMA transmission; iv) the duration (hours) of the DL C-OFDMA transmission; and v) the respective lengths (in bits, octets, words, etc.) of each OFDMA transmission (that is part of the DL C-OFDMA transmission) in each WLAN.

[0060] According to some embodiments, the C-OFDMA-A frame 204 is configured to prompt one or more slave APs 44 to send respective DL OFDMA transmissions as part of a DL C-OFDMA transmission.

[0061] In one embodiment, the C-OFDMA-A frame 204 is a MAC layer data unit transmitted within a PHY data unit (e.g., a packet) not shown in FIG. 2 . In one embodiment, the network interface device 122 generates the C-OFDMA-A frame 204 (e.g., generated by the MAC processor 126, generated by the C-OFDMA controller 60, etc.). In one embodiment, the network interface device 122 generates and transmits a packet including the C-OFDMA-A frame (e.g., generated and transmitted by the PHY processor 130). In one embodiment, the C-OFDMA controller 60 generates the C-OFDMA-A frame 204, provides the C-OFDMA-A frame 204 to the PHY processor 130, and controls the PHY processor 130 to transmit the C-OFDMA-A frame 204 within the packet.

[0062] A prescribed period after the end of transmission of the C-OFDMA-A frame 204 (or a prescribed period after the end of transmission of the packet containing the C-OFDMA-A frame 204), the master AP and one or more slave APs transmit as part of a DL C-OFDMA transmission 208. In one embodiment, the prescribed period is a short interframe space (SIFS) as defined by the IEEE 802.11 standard. In other embodiments, the prescribed period is a suitable period other than a SIFS.

[0063] In response to receiving the C-OFDMA-A frame 204, as part of a DL C-OFDMA transmission, one or more slave APs generate and transmit, in respective frequency RUs, respective downlink orthogonal frequency division multiple access (DL OFDMA) transmissions 212 to one or more sets of client stations of the one or more slave APs. For ease of illustration, a DL-OFDMA transmission 212 from one slave AP is shown in FIG. 2, but in some scenarios, multiple slave APs transmit multiple DL OFDMA transmissions 212 in respective frequency RUs.

[0064] In an exemplary embodiment, in response to receiving the C-OFDMA-A frame 204, the slave AP 44 determines whether the slave AP 44 is to participate in the DL C-OFDMA transmission 208 by analyzing information in the C-OFDMA-A frame 204, such as one or more indicators (e.g., one or more basic service set (BSS) identifiers) of one or more WLANs to participate in the DL C-OFDMA transmission 208 (e.g., determined by the network interface 122, determined by the MAC processor 126, determined by the C-OFDMA controller 70, etc.). In response to determining that the slave AP 44 will engage in C-OFDMA transmission 208, the slave AP 44 determines the frequency segment that the slave AP 44 will use for DL ​​C-OFDMA transmission 208 by analyzing information in the C-OFDMA-A frame 204, such as an indicator of the frequency segment used by the slave AP 44, the frequency RU used by the slave AP 44 (e.g., determined by the network interface 122, determined by the MAC processor 126, determined by the C-OFDMA controller 70, etc.).

[0065] Additionally, in response to determining that the slave AP 44 will engage in the C-OFDMA transmission 208, the slave AP 44 generates a DL-OFDMA transmission 212. In one embodiment, the slave AP 44 generates the DL-OFDMA transmission 212 in accordance with parameters in the C-OFDMA-A frame 204, such as one or more of an indicator of the duration (hours) of the DL C-OFDMA transmission 208 and an indicator of the length (bits, octets, words, etc.) of the DL OFDMA transmission 212 by the slave AP 44, according to various embodiments. The AP 44 generates a plurality of MAC data units for the DL OFDMA transmission 212 (e.g., generated by the network interface 122, generated by the MAC processor 126, etc.) and provides the plurality of MAC data units to the PHY processor 130, the plurality of MAC data units being for client stations 48 in the WLAN managed by the slave AP 44. The AP 44 also generates and transmits a DL OFDMA transmission 212 (e.g., generated and transmitted by the network interface 122, generated and transmitted by the PHY processor 130, etc.) to include multiple MAC data units. Thus, the DL OFDMA transmission 212 includes multiple MPDUs for client stations 48 in the WLAN managed by the slave AP 44. In some embodiments, the DL OFDMA transmission 212 includes a multi-user multiple-input, multiple-output (MU-MIMO) transmission to multiple client stations 48 via multiple spatial streams. In some embodiments, the DL OFDMA transmission 212 is replaced by a MU-MIMO transmission to multiple client stations 48 via multiple spatial streams.

[0066] In one embodiment, the slave AP 44 controls the timing of the DL OFDMA transmission 212 (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 70, etc.), such that, according to one embodiment, the DL OFDMA transmission 212 begins substantially simultaneously (i.e., within 5%) with the initiation of the DL OFDMA transmission 216 by the master AP 34. For example, the slave AP 44 controls the timing of the DL OFDMA transmission 212 (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 70, etc.), such that the DL OFDMA transmission 212 begins a specified period of time after the end of reception of the C-OFDMA-A frame 204 (or a specified period of time after the end of reception of the packet containing the C-OFDMA-A frame 204). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the prescribed period is any suitable period other than SIFS.

[0067] Concurrently with the DL OFDMA transmission 212 by the slave AP 44, the master AP 34 transmits a DL OFDMA transmission 216 on a frequency segment that is different from the frequency segment used by the slave AP 44 for the DL OFDMA transmission 212. The DL OFDMA transmission 216 is to multiple client stations 38 in the WLAN managed by the master AP 34. The AP 34 generates multiple MAC data units for the DL OFDMA transmission 216 (e.g., generated by the network interface 122, generated by the MAC processor 126, etc.) and provides the multiple MAC data units to the PHY processor 130, the multiple MAC data units being for the multiple client stations 38 in the WLAN managed by the master AP 34. The AP 34 also generates and transmits the DL OFDMA transmission 216 (e.g., generated and transmitted by the network interface 122, generated and transmitted by the PHY processor 130, etc.) to include multiple MAC data units. Thus, the DL OFDMA transmission 216 includes multiple MPDUs for the client stations 38 in the WLAN managed by the master AP 34. In some embodiments, DL OFDMA transmission 216 includes multi-user multiple-input, multiple-output (MU-MIMO) transmission via multiple spatial streams to multiple client stations 38. In some embodiments, DL OFDMA transmission 216 is replaced by MU-MIMO transmission via multiple spatial streams to multiple client stations 38.

[0068] In one embodiment, the master AP 34 controls the timing of the DL OFDMA transmission 216 (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 60, etc.), such that, according to one embodiment, the DL OFDMA transmission 216 begins substantially simultaneously (i.e., within 5%) with the initiation of the DL OFDMA transmission 212 by the slave AP 44. For example, the slave AP 44 controls the timing of the DL OFDMA transmission 216 (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 60, etc.), such that the DL OFDMA transmission 216 begins a specified period after the end of the transmission of the C-OFDMA-A frame 204 (or a specified period after the end of the transmission of the packet that includes the C-OFDMA-A frame 204). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the prescribed period is any suitable period other than SIFS.

[0069] In response to receiving the DL OFDMA transmission 212, a client station 48 in the WLAN managed by the slave AP 44 transmits acknowledgement (ACK) information and / or block acknowledgement (BA) information in an UL transmission 232. In one embodiment, the UL transmission 232 is transmitted on the same frequency segment as the DL OFDMA transmission 212 was transmitted on.

[0070] The slave AP 44 receives the UL transmission 232 (e.g., by the network interface 122, by the MAC processor 126, by the PHY processor 130, etc.). In one embodiment, the slave AP 44 receives the UL transmission 232 over the same frequency segment as the frequency segment over which the DL OFDMA transmission 212 was sent.

[0071] In response to receiving the DL OFDMA transmission 216, the client stations 38 in the WLAN managed by the master AP 34 transmit ACK and / or BA information in an UL transmission 236. In one embodiment, the UL transmission 236 is transmitted on the same frequency segment as the DL OFDMA transmission 216 was transmitted on.

[0072] The master AP 34 receives the UL transmission 236 (e.g., by the network interface 122, by the MAC processor 126, by the PHY processor 130, etc.). In one embodiment, the master AP 34 receives the UL transmission 236 over the same frequency segment over which the DL OFDMA transmission 216 was sent.

[0073] In one embodiment, the UL transmission 236 and the UL transmission 232 by the slave AP 44 are sent simultaneously.

[0074] In one embodiment, the duration of the UL transmission 232 is specified in the C-OFDMA-A frame 204. For example, according to one embodiment, the C-OFDMA-A frame 204 includes an indication of the duration of the UL transmission 232.

[0075] In one embodiment, the slave AP 44 includes an indicator of the duration of the UL transmission 232 in the DL OFDMA transmission 212 (e.g., included in the network interface 122, included in the MAC processor 126, included in the C-OFDMA controller 70, etc.), and the client station 48 uses the indicator of the duration of the UL transmission 232 to generate the UL transmission 232 to have the indicated duration (e.g., used by the network interface 122, used by the MAC processor 126, used by the C-OFDMA controller 80, etc.). In another embodiment, the client station 48 receives the C-OFDMA-A frame 204 and uses the indicator of the duration of the UL transmission 232 in the C-OFDMA-A frame 204 (e.g., used by the network interface 122, used by the MAC processor 126, used by the C-OFDMA controller 80, etc.) to generate the UL transmission 232 to have the indicated duration.

[0076] Figure 3 is a diagram of another exemplary C-OFDMA DL packet exchange 300 in a communication system, such as communication system 10 of Figure 1A or another suitable communication system, according to another embodiment. Figure 3 is described with reference to Figures 1A-1C for illustrative purposes. However, in some embodiments, C-OFDMA DL packet exchange 300 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0077] In the packet exchange 300, in response to receiving the C-OFDMA-A frame 204, the slave AP 44 generates and transmits an ACK 304 acknowledging the C-OFDMA-A frame 204. In one embodiment, the slave AP 44 generates and transmits a packet including the ACK 304, which occupies the same frequency bandwidth as the C-OFDMA-A frame 204. According to one embodiment, when the C-OFDMA-A frame 204 is addressed to multiple slave APs 44, the multiple slave APs 44 transmit their respective ACKs 304 via different spatial streams using UL MU-MIMO, with each transmission occupying the same frequency bandwidth as the C-OFDMA-A frame 204. For example, in one embodiment, the C-OFDMA-A frame 204 indicates the spatial streams that the multiple slave APs 44 use to transmit their ACKs 304.

[0078] In another embodiment, when the C-OFDMA-A frame 204 is addressed to multiple slave APs 44, the multiple slave APs 44 transmit their respective ACKs 304 at different times, with each transmission occupying the same frequency bandwidth as the C-OFDMA-A frame 204. For example, in one embodiment, the C-OFDMA-A frame 204 indicates the order in which the multiple slave APs 44 transmit their ACKs 304.

[0079] In one embodiment, the slave AP 44 controls the timing of transmission of the ACK 304 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.), so that transmission of the ACK 304 (or a packet including the ACK 304) begins a specified period after the end of reception of the C-OFDMA-A frame 204 (or a specified period after the end of reception of the packet including the C-OFDMA-A frame 204). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period different from SIFS.

[0080] In one embodiment, the slave AP 44 controls the timing of the DL OFDMA transmission 212 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that the transmission begins a specified period after the end of the transmission of the ACK 304 (or a specified period after the end of the transmission of the packet containing the ACK 304). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period other than SIFS. When multiple slave APs 44 transmit multiple ACKs 304 at different times, the slave APs 44 control the timing of the transmission of the DL OFDMA transmission 212 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that the transmission begins a specified period after the end of transmission of the last-occurring ACK 304 (or a specified period after the end of transmission of the packet including the last-occurring ACK 304).

[0081] In one embodiment, the master AP 34 controls the timing of the DL OFDMA transmissions 216 (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 60, etc.) so that the transmission begins a predetermined period after the end of the ACK 304 (or a predetermined period after the end of the packet containing the ACK 304). When multiple slave APs 44 transmit multiple ACKs 304 at different times, the master AP 34 controls the timing of the DL OFDMA transmissions 216 (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 60, etc.) so that the transmission begins a predetermined period after the end of the last ACK 304 (or a predetermined period after the end of the packet containing the last ACK 304).

[0082] 4 is a diagram of yet another exemplary C-OFDMA DL packet exchange 400 in a communication system, such as communication system 10 of FIG. 1A or another suitable communication system, in accordance with yet another embodiment. In some embodiments, C-OFDMA DL packet exchange 400 is useful in situations involving channel switching in one or more WLANs involving C-OFDMA transmissions.

[0083] Figure 4 is described with reference to Figures 1A-1C for illustrative purposes, however, in some embodiments, C-OFDMA DL packet exchange 400 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the example communication devices of Figures 1B-1C.

[0084] In packet exchange 400, the slave AP 44 generates and transmits a C-OFDMA-A frame 404 in response to receiving the C-OFDMA-A frame 204. In one embodiment, the C-OFDMA-A frame 404 is a copy of the C-OFDMA-A frame 204. The slave AP 44 generates and transmits a packet including the OFDMA-A frame 404, where the packet occupies a frequency segment indicated in the C-OFDMA-A frame 204 (e.g., a frequency segment used by the slave AP 44 for C-OFDMA transmission 208). According to one embodiment, when the C-OFDMA-A frame 204 is addressed to multiple slave APs 44, the multiple slave APs 44 transmit respective C-OFDMA-A frames 404 in respective frequency segments, where each C-OFDMA-A frame 404 is a copy of the C-OFDMA-A frame 204. For example, in one embodiment, the C-OFDMA-A frame 204 indicates the respective frequency segments that multiple slave APs 44 use for C-OFDMA transmissions 208 .

[0085] In addition, the master AP 34 generates a C-OFDMA-A frame 408 and transmits the C-OFDMA-A frame 408 simultaneously (e.g., within a packet) with the transmission of the C-OFDMA-A frame 404. In one embodiment, the C-OFDMA-A frame 408 is a copy of the C-OFDMA-A frame 204.

[0086] In one embodiment, generating the packet including the C-OFDMA-A frame 204 includes scrambling the C-OFDMA-A frame 204 (e.g., by a scrambler circuit of the PHY processor 130) using a first scrambling seed (e.g., an initial value for seeding a scrambling algorithm implemented by the scrambler circuit) in accordance with a scrambling algorithm, and generating the packet including the C-OFDMA-A frame 404 / 408 includes scrambling the C-OFDMA-A frame 404 / 408 (e.g., by a scrambler circuit of the PHY processor 130) using a second scrambling seed (e.g., an initial value for seeding a scrambling algorithm implemented by the scrambler circuit) in accordance with the scrambling algorithm. In one embodiment, the first scrambling seed is the same as the second scrambling seed. In another embodiment, the first scrambling seed is different from the second scrambling seed. In one embodiment, generating a packet including the C-OFDMA-A frame 404 / 408 includes using one or any suitable combination of two or more of: i) the same modulation and coding scheme (MCS) as used for the packet including the C-OFDMA-A frame 204; ii) the same data rate as used for the packet including the C-OFDMA-A frame 204; iii) the same number of spatial streams as used for the packet including the C-OFDMA-A frame 204; iv) the same PPDU format as used for the packet including the C-OFDMA-A frame 204;

[0087] In one embodiment, the slave AP 44 controls the timing of transmission of the C-OFDMA-A frame 404 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that transmission of the C-OFDMA-A frame 404 (or a packet including the C-OFDMA-A frame 404) begins a specified period after the end of reception of the C-OFDMA-A frame 204 (or a specified period after the end of reception of the packet including the C-OFDMA-A frame 204). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period other than SIFS.

[0088] In one embodiment, the master AP 34 controls the timing of the transmission of the C-OFDMA-A frame 408 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 60, etc.) so that the transmission of the C-OFDMA-A frame 408 (or a packet including the C-OFDMA-A frame 408) begins a specified period after the end of the transmission of the C-OFDMA-A frame 204 (or a specified period after the end of the transmission of the packet including the C-OFDMA-A frame 204). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period other than SIFS.

[0089] After transmitting C-OFDMA-A frame 404 and C-OFDMA-A frame 408, the master AP transmits a C-OFDMA trigger frame 420 to prompt slave AP 44 to transmit a portion of C-OFDMA transmission 208. In one embodiment, C-OFDMA trigger frame 420 includes some or all of the same information included in C-OFDMA-A frame 204, such as one or any suitable combination of two or more of: i) an indicator of one or more WLANs involved in the DL C-OFDMA transmission; ii) the respective frequency bandwidths used in each WLAN for the DL C-OFDMA transmission; iii) the respective frequency RUs used in each WLAN for the DL C-OFDMA transmission; iv) the duration (hours) of the DL C-OFDMA transmission; and v) the respective lengths (in bits, octets, words, etc.) of each OFDMA transmission (that is part of the DL C-OFDMA transmission) for each WLAN, according to various embodiments.

[0090] According to some embodiments, the C-OFDMA trigger frame 420 is configured to prompt one or more slave APs 44 to send their respective DL OFDMA transmissions as part of the DL C-OFDMA transmission 208 .

[0091] In one embodiment, the C-OFDMA trigger frame 420 is a MAC layer data unit transmitted within a PHY data unit (e.g., a packet), not shown in FIG. 2 . In one embodiment, the network interface device 122 generates the C-OFDMA trigger frame 420 (e.g., generated by the MAC processor 126, generated by the C-OFDMA controller 60, etc.). In one embodiment, the network interface device 122 generates and transmits a packet including the C-OFDMA trigger frame 420 (e.g., generated and transmitted by the PHY processor 130). In one embodiment, the C-OFDMA controller 60 generates the C-OFDMA trigger frame 420, provides the C-OFDMA trigger frame 420 to the PHY processor 130, and controls the PHY processor 130 to transmit the C-OFDMA trigger frame 420 within the packet.

[0092] A prescribed period after the end of transmission of the C-OFDMA trigger frame 420 (or a prescribed period after the end of transmission of the packet containing the C-OFDMA trigger frame 420), the master AP and one or more slave APs transmit as part of the DL C-OFDMA transmission 208. In one embodiment, the prescribed period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the prescribed period is a suitable period other than SIFS.

[0093] Figure 5 is a diagram of an exemplary acknowledgement packet exchange 500 for DL ​​C-OFDMA transmission in a communication system, such as communication system 10 of Figure 1A or another suitable communication system, according to one embodiment. Figure 5 is described with reference to Figures 1A-1C for illustrative purposes. In some embodiments, however, acknowledgement packet exchange 500 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0094] According to various embodiments, the acknowledgement packet exchange 500 is used in connection with any of the DL C-OFDMA transmissions of FIGS. 2-4 or other suitable DL C-OFDMA transmissions.

[0095] In the acknowledgement packet exchange 500, each set of client stations corresponding to each WLAN transmits its respective acknowledgement information at a different time. In some embodiments, the C-OFDMA-A frame 204 includes an indication of the order in which the slave AP 44 prompts each set of client stations to transmit their respective acknowledgement information. In some embodiments utilizing the C-OFDMA trigger frame 420 (FIG. 4), the C-OFDMA trigger frame 420 additionally or alternatively includes an indication of the order in which the slave AP 44 prompts each set of client stations to transmit their respective acknowledgement information.

[0096] After the DL C-OFDMA transmission 208, the master AP 34 generates and transmits a multi-user block acknowledgment request (MU-BAR) frame 504. In one embodiment, the MU-BAR frame 504 is included in a packet (not shown). In one embodiment, the network interface device 122 generates the MU-BAR frame 504 (e.g., generated by the MAC processor 126), and the network interface device 122 generates and transmits the packet including the MU-BAR frame 504 (e.g., generated and transmitted by the PHY processor 130). The MU-BAR frame 504 is configured to prompt client stations 38 of the WLAN managed by the master AP 34 to transmit acknowledgement information for the DL OFDMA transmission 216 to the master AP 34 in an UL transmission 508 (e.g., an UL OFDMA transmission, an UL MU-MIMO transmission, etc.). In response to the MU-BAR frame 504 , the client station 38 of the WLAN managed by the master AP 34 sends acknowledgement information for the DL OFDMA transmission 216 in an UL transmission 508 .

[0097] In one embodiment, the packet containing the MU-BAR frame 504 and the UL transmission 508 is transmitted in the same frequency segment as the DL OFDMA transmission 216 is transmitted.

[0098] After the UL transmission 508, the slave AP 44 generates and transmits an MU-BAR frame 520. In one embodiment, the MU-BAR frame 520 is included in a packet (not shown). In one embodiment, the network interface device 122 generates the MU-BAR frame 520 (e.g., generated by the MAC processor 126), and the network interface device 122 generates and transmits the packet including the MU-BAR frame 520 (e.g., generated and transmitted by the PHY processor 130). The MU-BAR frame 520 is configured to prompt the client stations 48 of the WLAN managed by the slave AP 44 to transmit acknowledgement information for the DL OFDMA transmission 212 to the slave AP 44 in an UL transmission 524 (e.g., an UL OFDMA transmission, an UL MU-MIMO transmission, etc.). In response to the MU-BAR frame 520, the client stations 48 of the WLAN managed by the slave AP 44 transmit acknowledgement information for the DL OFDMA transmission 212 in the UL transmission 524.

[0099] In one embodiment, the packet containing the MU-BAR frame 520 and the UL transmission 524 is transmitted in the same frequency segment as the DL OFDMA transmission 212 was transmitted.

[0100] Figure 6 is a diagram of another exemplary acknowledgment packet exchange 600 for DL ​​C-OFDMA transmission in a communication system, such as the communication system 10 of Figure 1A or another suitable communication system, according to another embodiment. Figure 6 is described with reference to Figures 1A-1C for illustrative purposes. In some embodiments, however, the acknowledgment packet exchange 600 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0101] According to various embodiments, the acknowledgement packet exchange 600 may be used in conjunction with any of the DL C-OFDMA transmissions of FIGS. 2-4 or any other suitable DL C-OFDMA transmission.

[0102] In acknowledgement packet exchange 600, each set of client stations corresponding to each WLAN simultaneously transmits their respective acknowledgement information as part of an UL C-OFDMA transmission.

[0103] After the DL C-OFDMA transmission 208, the master AP 34 and the slave AP 44 transmit the MU-BAR frame as part of a further DL C-OFDMA transmission 604. In one embodiment, the packet containing the MU-BAR frame 504 and the UL transmission 508 is transmitted on the same frequency segment as the DL OFDMA transmission 216 was transmitted, and the packet containing the MU-BAR frame 520 and the UL transmission 524 is transmitted on the same frequency segment as the DL OFDMA transmission 212 was transmitted.

[0104] In one embodiment, the master AP 34 controls the timing of the transmission of the MU-BAR frame 504 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 60, etc.) so that the transmission of the MU-BAR frame 504 (or a packet including the MU-BAR frame 504) begins a predetermined period after the end of the DL OFDMA transmission 216. In one embodiment, the predetermined period is SIFS as defined by the IEEE 802.11 standard. In other embodiments, the predetermined period is a suitable period other than SIFS. In one embodiment, the slave AP 44 controls the timing of the transmission of the MU-BAR frame 520 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that the transmission of the MU-BAR frame 520 (or a packet including the MU-BAR frame 520) begins a predetermined period after the end of the DL OFDMA transmission 212. In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In another embodiment, the specified period is a suitable period other than SIFS.

[0105] 7 is a diagram of another exemplary acknowledgment packet exchange 700 for DL ​​C-OFDMA transmission in a communication system, such as communication system 10 of FIG. 1A or another suitable communication system, according to yet another embodiment. FIG. 7 is described with reference to FIGS. 1A-1C for illustrative purposes. In some embodiments, however, acknowledgment packet exchange 700 is implemented in other suitable communication systems and / or with suitable communication devices different from the exemplary communication devices of FIGS. 1B-1C.

[0106] According to various embodiments, the acknowledgement packet exchange 700 may be used in conjunction with any of the DL C-OFDMA transmissions of FIGS. 2-4 or any other suitable DL C-OFDMA transmission.

[0107] The acknowledgement packet exchange 700 is similar to the acknowledgement packet exchange 600 of FIG. 6, except that the master AP 34 generates and transmits an additional C-OFDMA-A frame 704 for the DL C-OFDMA transmission 604 .

[0108] Figure 8 is a diagram of an exemplary C-OFDMA uplink (UL) packet exchange 800 in a communication system, such as the communication system 10 of Figure 1A or another suitable communication system, according to one embodiment. Figure 8 is described with reference to Figures 1A-1C for illustrative purposes. However, in some embodiments, the C-OFDMA UL packet exchange 800 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0109] A master AP (e.g., master AP 34) generates and transmits a C-OFDMA-A frame 804 to one or more slave APs (e.g., slave AP 44). The C-OFDMA-A frame, according to one embodiment, announces the start of an UL C-OFDMA transmission involving multiple WLANs. According to various embodiments, the C-OFDMA-A frame 804 includes information about the UL C-OFDMA transmission, such as one or any suitable combination of: i) an indicator of one or more WLANs involved in the UL C-OFDMA transmission; ii) the respective frequency bandwidths used in each WLAN for the UL C-OFDMA transmission; iii) the respective frequency RUs used in each WLAN for the UL C-OFDMA transmission; iv) the duration (hours) of the UL C-OFDMA transmission; and v) the respective lengths (in bits, octets, words, etc.) of each OFDMA transmission (that is part of the UL C-OFDMA transmission) in each WLAN.

[0110] According to some embodiments, the C-OFDMA-A frame 804 is configured to prompt one or more slave APs 44 to transmit respective trigger frames, thereby prompting respective sets of client stations to transmit as part of an UL C-OFDMA transmission.

[0111] In one embodiment, the C-OFDMA-A frame 804 is a MAC layer data unit transmitted within a PHY data unit (e.g., a packet) not shown in FIG. 8 . In one embodiment, the network interface device 122 generates the C-OFDMA-A frame 804 (e.g., generated by the MAC processor 126, generated by the C-OFDMA controller 60, etc.). In one embodiment, the network interface device 122 generates and transmits a packet including the C-OFDMA-A frame 804 (e.g., generated by the PHY processor 130). In one embodiment, the C-OFDMA controller 60 generates the C-OFDMA-A frame 804, provides the C-OFDMA-A frame 804 to the PHY processor 130, and controls the PHY processor 130 to transmit the C-OFDMA-A frame 804 within the packet.

[0112] A predetermined period of time after the end of transmission of the C-OFDMA-A frame 804 (or after the end of transmission of the packet including the C-OFDMA-A frame 204) the master AP and one or more slave APs transmit as part of a DL C-OFDMA transmission 808. In one embodiment, the predetermined period of time is SIFS as defined by the IEEE 802.11 standard. In other embodiments, the predetermined period of time is a suitable period of time other than SIFS.

[0113] In response to receiving the C-OFDMA-A frame 804 and a portion of the DL C-OFDMA transmission 808, the one or more slave APs generate and transmit respective trigger frames 820 / 824 in respective frequency RUs to one or more sets of client stations of the one or more slave APs. For simplicity, one trigger frame 824 from one slave AP is shown in FIG. 8, but in some scenarios, multiple slave APs transmit multiple trigger frames in respective frequency RUs.

[0114] In an exemplary embodiment, in response to receiving the C-OFDMA-A frame 804, the slave AP 44 determines whether the slave AP 44 will be involved in the DL C-OFDMA transmission 808 by analyzing information in the C-OFDMA-A frame 804, such as one or more indicators (e.g., one or more BSS identifiers) of one or more WLANs involved in the UL C-OFDMA transmission signaled by the C-OFDMA-A frame 804 (e.g., determined by the network interface 122, determined by the MAC processor 126, determined by the C-OFDMA controller 70, etc.). In response to determining that the slave AP 44 will be involved in DL C-OFDMA transmission 808, the slave AP 44 determines the frequency segment that the slave AP 44 will use for the DL C-OFDMA transmission 808 by analyzing information in the C-OFDMA-A frame 804, such as an indicator of the frequency segment used by the slave AP 44, the frequency RU used by the slave AP 44 (e.g., determined by the network interface 122, determined by the MAC processor 126, determined by the C-OFDMA controller 70, etc.).

[0115] Additionally, in response to determining that the slave AP 44 will engage in DL C-OFDMA transmission 808, the slave AP 44 generates a trigger frame 824 (e.g., generated by the network interface 122, generated by the MAC processor 126, etc.). In one embodiment, the slave AP 44 generates the trigger frame 824 according to one or more parameters, such as an indicator of the frequency RU to be used for the UL C-OFDMA transmission, an indicator of the duration (time) of the UL C-OFDMA transmission, etc., according to various embodiments. For example, according to one embodiment, the trigger frame 824 is generated to specify each frequency RU within the frequency RU indicated by the C-OFDMA frame 804 that the client station of the slave 44 will use for the UL C-OFDMA transmission. As another example, according to one embodiment, the trigger frame 824 is generated to specify the duration of the UL C-OFDMA transmission indicated by the C-OFDMA-A frame 804.

[0116] Also, in response to determining that the slave AP 44 is to participate in the DL C-OFDMA transmission 808, the slave AP 44 generates and transmits (e.g., generated and transmitted by the network interface 122, generated and transmitted by the PHY processor 130, etc.) a packet including the trigger frame 824.

[0117] In one embodiment, the slave AP 44 controls the timing of the transmission of the trigger frame 824 (or the transmission of the packet including the trigger frame 824) (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that, according to one embodiment, the transmission of the trigger frame 824 (or the packet including the trigger frame 824) begins substantially simultaneously (i.e., within 5%) with the start of the transmission of the trigger frame 820 (or the packet including the trigger frame 820) by the master AP 34. For example, the slave AP 44 controls the timing of the packet including the trigger frame 824 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that the packet begins a predetermined period after the end of reception of the C-OFDMA-A frame 804 (or after the end of reception of the packet including the C-OFDMA-A frame 804). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In another embodiment, the specified period is a suitable period other than SIFS.

[0118] Concurrent with the transmission of the trigger frame 824 by the slave AP 44, the master AP 34 transmits the trigger frame 820 (or a packet included in the trigger frame 820) on a frequency segment different from the frequency segment used by the slave AP 44 for the trigger frame 824. In one embodiment, the master AP 34 controls the timing of the transmission of the trigger frame 820 (or a packet including the trigger frame 820) (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 60, etc.) so that, according to one embodiment, the transmission of the trigger frame 820 (or a packet including the trigger frame 820) begins substantially simultaneously (i.e., within 5%) with the start of the transmission of the trigger packet 824 (or a packet including the trigger frame 824) by the slave AP 44. For example, the master AP 34 controls the timing of the trigger frame 820 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 60, etc.) so that the trigger frame 820 (or a packet including the trigger frame 820) begins a specified period after the end of transmission of the C-OFDMA-A frame 804 (or a specified period after the end of transmission of the packet including the C-OFDMA-A frame 804). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period different from SIFS.

[0119] A trigger frame 820 from the master AP 34 and a trigger frame 824 from the slave AP 44 prompt UL C-OFDMA transmissions 812 by the client stations 34 / 38 in the WLANs managed by the master AP 34 and the slave AP 44. The UL C-OFDMA transmissions 812 include a UL OFDMA transmission 840 by the client station 38 in the WLAN managed by the master AP 34 and one or more UL OFDMA transmissions 844 by the client station 38 in one or more respective WLANs managed by one or more respective slave APs 44.

[0120] For example, in response to the trigger frame 820, the client stations 38 in the WLAN managed by the master AP 34 transmit as part of the UL OFDMA transmission 840. For example, the trigger frame 820 transmitted by the master AP 34 is configured to prompt at least a subset of the client stations 38 to transmit as part of the UL OFDMA transmission 840. In various embodiments, the trigger frame 820 is generated by the master AP 34 and indicates one or any suitable combination of two or more of: i) which client stations 38 will be involved in the UL OFDMA transmission 840; ii) the respective frequency RUs the client stations 38 will use for the UL OFDMA transmission 840; iii) each spatial stream the client stations 38 will use for the UL OFDMA transmission 840; and iv) the time length of the UL OFDMA transmission 840.

[0121] Similarly, in response to the trigger frame 824, the client stations 48 in the WLAN managed by the slave AP 44 transmit as part of a UL OFDMA transmission 844. For example, the trigger frame 824 transmitted by the slave AP 44 is configured to prompt at least a subset of the client stations 48 to transmit as part of the UL OFDMA transmission 844. In various embodiments, the trigger frame 824 is generated by the slave AP 44 and indicates one or any suitable combination of: i) which client stations 38 will be involved in the UL OFDMA transmission 844; ii) the respective frequency RUs the client stations 38 will use for the UL OFDMA transmission 844; iii) each spatial stream the client stations 38 will use for the UL OFDMA transmission 844; and iv) the time length of the UL OFDMA transmission 844.

[0122] According to one embodiment, client stations 38 involved in UL OFDMA transmission 840 are configured to transmit as part of UL OFDMA transmission 840 simultaneously with transmissions by client stations 48 involved in UL OFDMA transmission 844 (or vice versa). For example, according to one embodiment, client stations 38 involved in UL OFDMA transmission 840 are configured to begin transmission as part of UL OFDMA transmission 840 a predetermined period (e.g., SIFS or another suitable period) after end of reception of trigger frame 820 (or a predetermined period after end of reception of the packet containing trigger frame 820). Similarly, according to one embodiment, client stations 48 involved in UL OFDMA transmission 844 are configured to begin transmission as part of UL OFDMA transmission 844 a predetermined period (e.g., SIFS or another suitable period) after end of reception of trigger frame 824 (or a predetermined period after end of reception of the packet containing trigger frame 824).

[0123] Figure 9 is a diagram of another exemplary C-OFDMA UL packet exchange 900 in a communication system, such as the communication system 10 of Figure 1A or another suitable communication system, according to another embodiment. Figure 9 is described with reference to Figures 1A-1C for illustrative purposes. However, in some embodiments, the C-OFDMA DL packet exchange 900 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0124] In packet exchange 900, in response to receiving the C-OFDMA-A frame 804, the slave AP 44 generates and transmits an ACK 904 acknowledging the C-OFDMA-A frame 804. In one embodiment, the slave AP 44 generates and transmits a packet including the ACK 904, which occupies the same frequency bandwidth as the C-OFDMA-A frame 804. According to one embodiment, when the C-OFDMA-A frame 804 is addressed to multiple slave APs 44, the multiple slave APs 44 transmit their respective ACKs 904 via different spatial streams using UL MU-MIMO, with each transmission occupying the same frequency bandwidth as the C-OFDMA-A frame 804. For example, in one embodiment, the C-OFDMA-A frame 804 indicates the spatial streams that the multiple slave APs 44 use to transmit their ACKs 904.

[0125] In another embodiment, when the C-OFDMA-A frame 804 is addressed to multiple slave APs 44, the multiple slave APs 44 transmit their respective ACKs 904 at different times, with each transmission occupying the same frequency bandwidth as the C-OFDMA-A frame 804. For example, in one embodiment, the C-OFDMA-A frame 804 indicates the order in which the multiple slave APs 44 transmit their ACKs 904.

[0126] In one embodiment, the slave AP 44 controls the timing of transmission of the ACK 904 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.), so that transmission of the ACK 904 (or a packet including the ACK 904) begins a specified period after the end of reception of the C-OFDMA-A frame 804 (or a specified period after the end of reception of the packet including the C-OFDMA-A frame 804). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period different from SIFS.

[0127] In one embodiment, the slave AP 44 controls the timing of transmission of the trigger frame 824 (or a packet including the trigger frame 824) (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that transmission begins a specified period after the end of transmission of the ACK 904 (or a specified period after the end of transmission of the packet including the ACK 904). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period different from SIFS. When multiple slave APs 44 transmit multiple ACKs 904 at different times, the slave AP 44 controls the timing of transmission of the trigger frame 824 (or the packet including the trigger frame 824) (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.), so that transmission begins a specified period after the end of transmission of the last-occurring ACK 904 (or a specified period after the end of transmission of the packet including the last-occurring ACK 904).

[0128] In one embodiment, the master AP 34 controls (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 60, etc.) the timing of the transmission of the trigger frame 820 (or a packet including the trigger frame 820) so that the transmission begins a specified period after the end of the transmission of the ACK 904 (or a specified period after the end of the transmission of the packet including the ACK 904). When multiple slave APs 44 transmit multiple ACKs 904 at different times, the master AP 34 controls (e.g., via the network interface 122, the MAC processor 126, the C-OFDMA controller 60, etc.) the timing of the transmission of the trigger frame 820 (or a packet including the trigger frame 820) so that the transmission begins a specified period after the end of the transmission of the last ACK 904 (or a specified period after the end of the transmission of the packet including the last ACK 904).

[0129] 10 is a diagram of yet another exemplary C-OFDMA UL packet exchange 1000 in a communication system, such as the communication system 10 of FIG. 1A or another suitable communication system, in accordance with yet another embodiment. In some embodiments, the C-OFDMA DL packet exchange 1000 is useful in situations involving channel switching in one or more WLANs involved in C-OFDMA transmissions.

[0130] Figure 10 is described with reference to Figures 1A-1C for illustrative purposes, however, in some embodiments, the C-OFDMA DL packet exchange 1000 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the example communication devices of Figures 1B-1C.

[0131] In packet exchange 1000, the slave AP 44 generates and transmits a C-OFDMA-A frame 1004 in response to receiving the C-OFDMA-A frame 804. In one embodiment, the C-OFDMA-A frame 1004 is a copy of the C-OFDMA-A frame 804. The slave AP 44 generates and transmits a packet including the C-OFDMA-A frame 1004, which occupies a frequency segment indicated in the C-OFDMA-A frame 804 (e.g., a frequency segment used for UL OFDMA transmissions 844 by the WLAN managed by the slave AP 44). According to one embodiment, when the C-OFDMA-A frame 804 is addressed to multiple slave APs 44, the multiple slave APs 44 transmit respective C-OFDMA-A frames 1004 in respective frequency segments, and each C-OFDMA-A frame 1004 is a copy of the C-OFDMA-A frame 804. For example, in one embodiment, the C-OFDMA-A frame 804 indicates the respective frequency segments that multiple slave APs 44 use for C-OFDMA transmissions 1004 .

[0132] Additionally, the master AP 34 generates a C-OFDMA-A frame 1008 and transmits the C-OFDMA-A frame 1008 (e.g., in a packet) simultaneously with the transmission of the C-OFDMA-A frame 1004. In one embodiment, the C-OFDMA-A frame 1008 is a copy of the C-OFDMA-A frame 804.

[0133] In one embodiment, generating the packet including the C-OFDMA-A frame 804 includes scrambling the C-OFDMA-A frame 804 (e.g., by a scrambler circuit of the PHY processor 130) using a first scrambling seed (e.g., an initial value for seeding a scrambling algorithm implemented by the scrambler circuit) in accordance with a scrambling algorithm, and generating the packet including the C-OFDMA-A frame 1004 / 1008 includes scrambling the C-OFDMA-A frame 1004 / 1008 (e.g., by a scrambler circuit of the PHY processor 130) using a second scrambling seed (e.g., an initial value for seeding a scrambling algorithm implemented by the scrambler circuit) in accordance with the scrambling algorithm. In one embodiment, the first scrambling seed is the same as the second scrambling seed. In another embodiment, the first scrambling seed is different from the second scrambling seed. In one embodiment, generating a packet including the C-OFDMA-A frame 1004 / 1008 includes using one or any suitable combination of two or more of: i) the same MCS used for the packet including the C-OFDMA-A frame 804; ii) the same data rate used for the packet including the C-OFDMA-A frame 804; iii) the same number of spatial streams used for the packet including the C-OFDMA-A frame 804; iv) the same PPDU format used for the packet including the C-OFDMA-A frame 804;

[0134] In one embodiment, the slave AP 44 controls the timing of transmission of the C-OFDMA-A frame 1004 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 70, etc.) so that transmission of the C-OFDMA-A frame 1004 (or a packet including the C-OFDMA-A frame 1004) begins a specified period after the end of reception of the C-OFDMA-A frame 804 (or a specified period after the end of reception of the packet including the C-OFDMA-A frame 804). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period different from SIFS.

[0135] In one embodiment, the master AP 34 controls the timing of the transmission of the C-OFDMA-A frame 1008 (e.g., controlled by the network interface 122, controlled by the MAC processor 126, controlled by the C-OFDMA controller 60, etc.) so that the transmission of the C-OFDMA-A frame 1008 (or a packet including the C-OFDMA-A frame 1008) begins a specified period after the end of the transmission of the C-OFDMA-A frame 804 (or a specified period after the end of the transmission of the packet including the C-OFDMA-A frame 804). In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period other than SIFS.

[0136] After transmitting C-OFDMA-A frame 1004 and C-OFDMA-A frame 1008, the master AP transmits a C-OFDMA trigger frame 1020 to prompt the slave AP 44 to transmit a portion of the C-OFDMA transmission 808. In one embodiment, the C-OFDMA trigger frame 1020 includes some or all of the same information included in the C-OFDMA-A frame 804, such as one or any suitable combination of two or more of: i) an indicator of one or more WLANs involved in the DL C-OFDMA transmission; ii) the respective frequency bandwidths used in each WLAN for the DL C-OFDMA transmission; iii) the respective frequency RUs used in each WLAN for the DL C-OFDMA transmission; iv) the duration (hours) of the DL C-OFDMA transmission; v) the respective lengths (in bits, octets, words, etc.) of each OFDMA transmission (that is part of the DL C-OFDMA transmission) for each WLAN, according to various embodiments.

[0137] According to some embodiments, the C-OFDMA trigger frame 1020 is configured to prompt one or more slave APs 44 to send their respective DL OFDMA transmissions as part of the DL C-OFDMA transmission 808 .

[0138] In one embodiment, the C-OFDMA trigger frame 1020 is a MAC layer data unit transmitted within a PHY data unit (e.g., a packet), not shown in FIG. 2 . In one embodiment, the network interface device 122 generates the C-OFDMA trigger frame 1020 (e.g., generated by the MAC processor 126, generated by the C-OFDMA controller 60, etc.). In one embodiment, the network interface device 122 generates and transmits a packet including the C-OFDMA trigger frame 1020 (e.g., generated and transmitted by the PHY processor 130). In one embodiment, the C-OFDMA controller 60 generates the C-OFDMA trigger frame 1020, provides the C-OFDMA trigger frame 1020 to the PHY processor 130, and controls the PHY processor 130 to transmit the C-OFDMA trigger frame 1020 within the packet.

[0139] A prescribed period after the end of transmission of the C-OFDMA trigger frame 1020 (or a prescribed period after the end of transmission of the packet containing the C-OFDMA trigger frame 1020), the master AP and one or more slave APs transmit as part of a DL C-OFDMA transmission 808. In one embodiment, the prescribed period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the prescribed period is a suitable period other than SIFS.

[0140] Figure 11 is a diagram of an exemplary acknowledgment packet exchange 1100 for an UL C-OFDMA transmission in a communication system, such as the communication system 10 of Figure 1A or another suitable communication system, according to one embodiment. Figure 11 is described with reference to Figures 1A-1C for illustrative purposes. In some embodiments, however, the acknowledgment packet exchange 1100 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0141] According to various embodiments, the acknowledgement packet exchange 1100 may be used in conjunction with any of the UL C-OFDMA transmissions of FIGS. 8-10 or any other suitable UL C-OFDMA transmission.

[0142] A predetermined period after the end of the UL C-OFDMA transmission 812, the master AP 34 begins transmitting a packet containing a C-OFDMA-A frame 1104. In one embodiment, the predetermined period is SIFS as defined by the IEEE 802.11 standard. In other embodiments, the predetermined period is a suitable period other than SIFS.

[0143] The master AP 34 generates a C-OFDMA-A frame 1104, and after completing the UL C-OFDMA transmission 812, the master AP 34 transmits the C-OFDMA-A frame 1104 to one or more slave APs, such as the slave AP 44. According to one embodiment, the C-OFDMA-A frame 1104 announces the start of the DL C-OFDMA transmission 856. According to various embodiments, the C-OFDMA-A frame 1104 includes information about the DL C-OFDMA transmission 856, such as one or any suitable combination of two or more of: i) an indicator of one or more WLANs involved in the DL C-OFDMA transmission, ii) the respective frequency bandwidths used in each WLAN for the DL C-OFDMA transmission, iii) the respective frequency RUs used in each WLAN for the DL C-OFDMA transmission, iv) the duration (hours) of the DL C-OFDMA transmission, v) the respective lengths (in bits, octets, words, etc.) of each OFDMA transmission (that is part of the DL C-OFDMA transmission) in each WLAN, etc. In some embodiments, the RUs used for the DL C-OFDMA transmission 856 are the same as the RUs used for the UL C-OFDMA transmission 812.

[0144] According to some embodiments, the C-OFDMA-A frame 1104 is configured to prompt one or more slave APs 44 to transmit respective ACK or BA frames for the UL C-OFDMA transmission 812 .

[0145] In one embodiment, the C-OFDMA-A frame 1104 is a MAC layer data unit transmitted within a PHY data unit (e.g., a packet) not shown in FIG. 11 . In one embodiment, the network interface device 122 generates the C-OFDMA-A frame 1104 (e.g., generated by the MAC processor 126, generated by the C-OFDMA controller 60, etc.). In one embodiment, the network interface device 122 generates and transmits a packet including the C-OFDMA-A frame 1104 (e.g., generated and transmitted by the PHY processor 130). In one embodiment, the C-OFDMA controller 60 generates the C-OFDMA-A frame 1104, provides the C-OFDMA-A frame 1104 to the PHY processor 130, and controls the PHY processor 130 to transmit the C-OFDMA-A frame 1104 within a packet.

[0146] In one embodiment, transmission of a packet containing a C-OFDMA-A frame begins a specified period of time after the end of the UL C-OFDMA transmission 812. In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In other embodiments, the specified period is a suitable period other than SIFS.

[0147] In response to receiving the C-OFDMA-A frame 1104 and a portion of the DL C-OFDMA transmission 856, the one or more slave APs generate and transmit respective ACK or BA frames 860 / 864 in respective frequency RUs to one or more sets of client stations of the one or more slave APs. In one embodiment, the DL C-OFDMA transmission 856 begins a predetermined period after the end of the transmission of the C-OFDMA-A frame 1104 (or a predetermined period after the end of the transmission of the packet containing the C-OFDMA-A frame 1104). In one embodiment, the predetermined period is SIFS as defined by the IEEE 802.11 standard. In other embodiments, the predetermined period is a suitable period other than SIFS.

[0148] Figure 12 is a diagram of an exemplary packet exchange 1200 involving UL C-OFDMA transmission in a communication system, such as the communication system 10 of Figure 1A, or another suitable communication system, according to one embodiment. Figure 12 is described with reference to Figures 1A-1C for illustrative purposes. However, in some embodiments, packet exchange 1200 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0149] According to various embodiments, packet switch 1200 may be used in conjunction with any of the UL C-OFDMA transmissions of FIGS. 8-10, or in conjunction with any other suitable UL C-OFDMA transmission.

[0150] 8-10 , DL C-OFDMA transmission 1204 immediately follows UL C-OFDMA transmission 812, and DL C-OFDMA transmission 1204 does not simply include ACK / BA information for UL C-OFDMA transmission 812. A predetermined period after the end of UL C-OFDMA transmission 812, master AP 34 initiates DL-OFDMA transmission 1220, and slave AP 44 initiates DL-OFDMA transmission 1224. DL-OFDMA transmission 1220 does not simply include ACK / BA information for UL C-OFDMA transmission 812, and DL-OFDMA transmission 1224 does not simply include ACK / BA information for UL C-OFDMA transmission 812. According to one embodiment, for example, DL-OFDMA transmission 1220 includes user data for client station 38, and DL-OFDMA transmission 1224 includes user data for client station 48.

[0151] In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In another embodiment, the specified period is a suitable period other than SIFS.

[0152] In various embodiments, the DL C-OFDMA transmission 1204 is acknowledged by the client station 38 / 48 using an acknowledgement technique such as those described with reference to any of FIGS. 2-7, or using other suitable acknowledgement techniques (not shown in FIG. 12).

[0153] Figure 13 is a diagram of an exemplary packet exchange 1300 involving DL C-OFDMA transmission in a communication system, such as the communication system 10 of Figure 1A, or another suitable communication system, according to one embodiment. Figure 13 is described with reference to Figures 1A-1C for illustrative purposes. However, in some embodiments, the packet exchange 1300 is implemented in other suitable communication systems and / or with suitable communication devices that differ from the exemplary communication devices of Figures 1B-1C.

[0154] According to various embodiments, packet switch 1300 may be used in conjunction with any of the DL C-OFDMA transmissions of FIGS. 2-7, or in conjunction with any other suitable DL C-OFDMA transmission.

[0155] 2 through 7, UL C-OFDMA transmission 1304 immediately follows DL C-OFDMA transmission 208, and UL C-OFDMA transmission 1304 does not simply include ACK / BA information for DL ​​C-OFDMA transmission 208. A predetermined period after the end of DL C-OFDMA transmission 208, client station 38 of master AP 34 begins UL OFDMA transmission 1320, and client station 44 of slave AP 44 begins DL-OFDMA transmission 1324. UL OFDMA transmission 1320 does not simply include ACK / BA information for DL ​​C-OFDMA transmission 216, and UL OFDMA transmission 1324 does not simply include ACK / BA information for DL ​​C-OFDMA transmission 212. According to one embodiment, for example, UL OFDMA transmission 1320 includes user data from client station 38, and UL OFDMA transmission 1324 includes user data from client station 48.

[0156] In one embodiment, the specified period is SIFS as specified by the IEEE 802.11 standard. In another embodiment, the specified period is a suitable period other than SIFS.

[0157] In some embodiments, DL C-OFDMA transmission 216 includes a trigger frame prompting client station 38 to transmit UL C-OFDMA transmission 1320, and DL C-OFDMA transmission 212 includes a trigger frame prompting client station 48 to transmit UL C-OFDMA transmission 1324.

[0158] In various embodiments, the UL C-OFDMA transmission 1304 is acknowledged by the master AP 34 and the slave AP 44 using an acknowledgement technique such as those described with reference to any of Figures 8 through 11, or using other suitable acknowledgement techniques (not shown in Figure 13).

[0159] In some embodiments, the C-OFDMA-A frames described in connection with Figures 2-13 include control frames. For example, the IEEE 802.11 standard defines a frame header having a type subfield and a subtype field. In one embodiment, the type subfield of the C-OFDMA-A frame is set to a value to indicate a control type frame, and the subtype subfield of the C-OFDMA-A frame is set to a value to indicate that the control frame is a C-OFDMA-A frame.

[0160] In some embodiments, the C-OFDMA-A frame described in connection with Figures 2 through 13 includes a trigger frame that is a control frame subtype. For example, the type subfield of the C-OFDMA-A frame is set to a value to indicate a control type frame, and the subtype subfield of the C-OFDMA-A frame is set to a value to indicate that the control frame is a trigger frame. The current draft of the IEEE 802.11ax standard defines a trigger frame format having a trigger type subfield, which can be set to one of a plurality of values ​​to indicate one of a plurality of different types of trigger frame. In one embodiment, the C-OFDMA-A frame includes a trigger type subfield set to a value to indicate that the trigger frame is a C-OFDMA-A frame.

[0161] As described above, according to various embodiments, the C-OFDMA-A frame includes information regarding the announced C-OFDMA transmission, such as one or any suitable combination of two or more of: i) an identifier of the WLAN of the slave AP to participate in the C-OFDMA transmission; ii) the respective frequency bandwidth used in each WLAN; iii) the respective frequency RU used in each WLAN; iv) the time length (hours) of the cooperative OFDMA transmission; v) the respective length (bits, octets, words, etc.) of each OFDMA transmission in each WLAN; In some embodiments, the C-OFDMA-A frame additionally or alternatively includes one or any suitable combination of two or more of an indication of the type of long training field (LTF) to be included in the PHY preamble of the C-OFDMA transmission (e.g., where the communication protocol provides for multiple different types of LTFs), an indication of the number of LTFs to be included in the PHY preamble of the C-OFDMA transmission (e.g., where the communication protocol provides for a different number of LTFs), an indication of the length of a signal field to be included in the PHY preamble of the C-OFDMA transmission (e.g., where the signal field is a variable length signal field), etc.

[0162] According to various embodiments, in a DL C-OFDMA transmission such as that described above in connection with FIGS. 2-7, the C-OFDMA-A frame may additionally or alternatively include one or both of: i) a UL acknowledgment type (e.g., whether the DL C-OFDMA transmission is acknowledged by the client station 38 / 48 with an immediate acknowledgment (e.g., solicited by a trigger frame in the DL C-OFDMA transmission), such as those shown in FIGS. 2-4; whether the DL C-OFDMA transmission is acknowledged by the client station 38 / 48 with a BA solicited by a MU-BAR separate from the DL C-OFDMA transmission, such as those shown in FIGS. 5-7); and ii) a UL ACK / BA duration (e.g., whether the DL C-OFDMA transmission is acknowledged by the client station 38 / 48 with an immediate acknowledgment). In some embodiments, an indicator of the duration of the UL ACK / BA transmissions 232 and 236 is included elsewhere, such as in a trigger frame included in the DL C-OFDMA transmissions (212 / 216), such as in the MU-BAR frames 504 / 520.

[0163] In some embodiments, the frequency bandwidth and / or RUs are indicated in the C-OFDMA-A frame in units of 20 MHz. In some embodiments, the frequency bandwidth and / or RUs are indicated in the C-OFDMA-A frame in units of 40 MHz. In some embodiments, when the frequency bandwidth allocated to a particular WLAN for C-OFDMA transmission is less than or equal to 160 MHz, the frequency bandwidth and / or RUs allocated to the WLAN are indicated in the C-OFDMA-A frame in units of 20 MHz, and when the frequency bandwidth allocated to a particular WLAN for C-OFDMA transmission is greater than 160 MHz, the frequency bandwidth and / or RUs allocated to the WLAN are indicated in the C-OFDMA-A frame in units of 40 MHz.

[0164] In one embodiment, a C-OFDMA-A frame includes one or more resource allocation fields corresponding to one or more respective WLANs to participate in C-OFDMA transmission. According to an exemplary embodiment, in the illustrated example, each resource allocation field in the C-OFDMA-A frame includes: i) an identifier of the BSS (e.g., a 48-bit MAC address of the slave AP, a color ID of the BSS, a 5-bit hash of the MAC address of the slave MAC address, and a 6-bit color ID of the BSS, or another suitable identifier); ii) the frequency bandwidth of the frequency segment used for C-OFDMA transmission; and iii) a starting 20 MHz subchannel of the frequency segment. In some embodiments (such as those shown in FIG. 12 ) in which a DL C-OFDMA transmission immediately follows a UL C-OFDMA transmission, the C-OFDMA-A frame includes: i) an indication of the frequency bandwidth and starting subchannel for the UL C-OFDMA transmission; and ii) an indication of the frequency bandwidth and starting subchannel for the DL C-OFDMA transmission. In other embodiments (such as that shown in FIG. 12) in which a DL C-OFDMA transmission immediately follows a UL C-OFDMA transmission, the C-OFDMA-A frame includes only one indication of the frequency bandwidth and starting subchannel for both the UL C-OFDMA transmission and the DL C-OFDMA transmission, i.e., the UL C-OFDMA transmission and the DL C-OFDMA transmission use the same frequency segment.

[0165] According to various embodiments, for DL ​​C-OFDMA transmission, each resource allocation field of the C-OFDMA-A frame further includes one or any suitable combination of two or more of an indicator of the type of LTF to be included in the PHY preamble of the DL C-OFDMA transmission, an indicator of the number of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the length or duration of the signal field to be included in the PHY preamble of the DL C-OFDMA transmission, an indicator of the duration of the DL C-OFDMA transmission, etc. In some embodiments (such as those shown in FIG. 4 ) in which the master AP 34 also transmits a C-OFDMA trigger frame (e.g., C-OFDMA trigger frame 420) to prompt a DL C-OFDMA transmission, the C-OFDMA-A frame does not include the indicator of the type of LTF, the indicator of the number of LTFs, the length or duration of the signal field, and the length or duration of the DL C-OFDMA transmission. For example, such information is instead included in the C-OFDMA trigger frame. In other embodiments (such as that shown in FIG. 4) in which the master AP 34 also transmits a C-OFDMA trigger frame (e.g., C-OFDMA trigger frame 420) to prompt a DL C-OFDMA transmission, the C-OFDMA-A frame includes one or any suitable combination of two or more of an indicator of the type of LTF, an indicator of the number of LTFs, a length or duration of the signal field, and a length or duration of the DL C-OFDMA transmission.

[0166] According to various embodiments, for a UL C-OFDMA transmission, each resource allocation field of the C-OFDMA-A frame further includes one or any suitable combination of two or more of an indication of the type of LTFs to be included in the PHY preamble of the UL C-OFDMA transmission, an indication of the number of LTFs to be included in the PHY preamble of the UL C-OFDMA transmission, an indication of the time length of the UL C-OFDMA transmission, etc. According to various embodiments, in other embodiments where a DL C-OFDMA transmission immediately follows a UL C-OFDMA transmission (such as that shown in FIG. 12), the C-OFDMA-A frame further includes, for a DL C-OFDMA transmission, one or any suitable combination of two or more of an indication of the type of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the number of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the length or duration of a signal field to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the duration of the DL C-OFDMA transmission, etc.

[0167] In some embodiments (such as those shown in FIG. 10 ) in which the master AP 34 also transmits a C-OFDMA trigger frame (e.g., C-OFDMA trigger frame 1020) to prompt the slave AP to transmit a trigger frame and trigger a UL C-OFDMA transmission, the C-OFDMA-A frame does not include an indicator of the type of LTF, an indicator of the number of LTFs, and an indicator of the length or duration of the UL C-OFDMA transmission. For example, such information is instead included in the C-OFDMA trigger frame. In other embodiments (such as those shown in FIG. 10 ) in which the master AP 34 also transmits a C-OFDMA trigger frame (e.g., C-OFDMA trigger frame 1020) to prompt a UL C-OFDMA transmission, the C-OFDMA-A frame includes one or any suitable combination of two or more of an indicator of the type of LTF, an indicator of the number of LTFs, and an indicator of the length or duration of the UL C-OFDMA transmission.

[0168] In some embodiments, a C-OFDMA-A frame is transmitted in a 20 MHz wide legacy PPDU (sometimes referred to as a "non-HT PPDU" in the IEEE 802.11 standard), and a replica of the PPDU is transmitted in each 20 MHz subchannel (sometimes referred to as a "non-HT replicated PPDU" in the IEEE 802.11 standard) to generate a full-bandwidth C-OFDMA-A transmission. As an illustrative example, eight replicas of a C-OFDMA-A frame are transmitted in eight non-HT replicated PPDUs in eight 20 MHz subchannels to generate a 160 MHz transmission. In some embodiments in which a C-OFDMA-A frame is transmitted in a non-HT PPDU (i.e., a legacy PPDU), the data rate at which the C-OFDMA-A frame is transmitted is limited to a data rate from a set of mandatory data rates defined by the communication protocol (e.g., the IEEE 802.11 standard). In some embodiments in which the C-OFDMA-A frame is transmitted in a non-HT PPDU (i.e., a legacy PPDU), the data rate at which the C-OFDMA-A frame is transmitted is limited to a data rate from a set of common data rates supported by both the master AP 34 and one or more slave APs 44 involved in the C-OFDMA transmission.

[0169] In other embodiments, the C-OFDMA-A frame is transmitted in another suitable 20 MHz wide PPDU (e.g., a PPDU compliant with the current draft of the IEEE 802.11ax standard, a PPDU compliant with the IEEE 802.11be standard currently under development, etc.), and a duplicate PPDU is transmitted in each 20 MHz subchannel to generate a full-bandwidth C-OFDMA-A transmission. In some embodiments in which the C-OFDMA-A frame is transmitted in a PPDU compliant with the current draft of the IEEE 802.11ax standard or the IEEE 802.11be standard currently under development, the MCS and number of spatial streams used to transmit the C-OFDMA-A frame are limited to the MCS / number of spatial streams combinations defined as mandatory by the IEEE 802.11ax standard / IEEE 802.11be standard. In other embodiments in which the C-OFDMA-A frame is transmitted in a PPDU that complies with the current draft of the IEEE 802.11ax standard or the IEEE 802.11be standard currently under development, the MCS and number of spatial streams used to transmit the C-OFDMA-A frame are limited to MCS / number of spatial streams combinations from a set of common MCS / number of spatial streams combinations supported by both the master AP 34 and one or more slave APs 44 involved in the C-OFDMA transmission.

[0170] In another embodiment, the C-OFDMA-A frame is transmitted in a single PPDU that occupies the complete bandwidth of the C-OFDMA-A transmission.

[0171] 4 and 10, a C-OFDMA trigger frame, such as C-OFDMA trigger frame 420 and C-OFDMA trigger frame 1020, includes a trigger frame that is a control frame subtype. For example, the type subfield of the C-OFDMA trigger frame is set to a value indicating a control type frame, and the subtype subfield of the C-OFDMA trigger frame is set to a value indicating that the control frame is a trigger frame. The current draft of the IEEE 802.11ax standard specifies a trigger frame format having a trigger type subfield, which may be set to one of a plurality of values ​​indicating one of a plurality of different types of trigger frame. In one embodiment, the C-OFDMA trigger frame includes a trigger type subfield set to a value indicating that the trigger frame is a C-OFDMA trigger frame.

[0172] According to various embodiments, the C-OFDMA trigger frame includes information regarding the C-OFDMA transmission, such as one or any suitable combination of two or more of: i) an identifier of the WLAN of the slave AP involved in the C-OFDMA transmission; ii) an indicator of the respective frequency bandwidth used in each WLAN; iii) an indicator of the respective frequency RU used in each WLAN; iv) an indicator of the time length (hours) of the cooperative OFDMA transmission; v) an indicator of the respective length (bits, octets, words, etc.) of each OFDMA transmission in each WLAN. In some embodiments, the C-OFDMA trigger frame additionally or alternatively includes one or any suitable combination of two or more of an indicator of the type of long training field (LTF) to be included in the PHY preamble of the C-OFDMA transmission (e.g., where the communication protocol provides for multiple different types of LTFs), an indicator of the number of LTFs to be included in the PHY preamble of the C-OFDMA transmission (e.g., where the communication protocol provides for a different number of LTFs), an indicator of the length of a signal field to be included in the PHY preamble of the C-OFDMA transmission (e.g., where the signal field is a variable length signal field), etc.

[0173] In some embodiments, the frequency bandwidth and / or RUs are indicated in the C-OFDMA trigger frame in units of 20 MHz. In some embodiments, the frequency bandwidth and / or RUs are indicated in the C-OFDMA trigger frame in units of 40 MHz. In some embodiments, when the frequency bandwidth allocated to a particular WLAN for C-OFDMA transmission is 160 MHz or less, the frequency bandwidth and / or RUs assigned to the WLAN are indicated in the C-OFDMA trigger frame in units of 20 MHz, and when the frequency bandwidth allocated to a particular WLAN for C-OFDMA transmission is greater than 160 MHz, the frequency bandwidth and / or RUs assigned to the WLAN are indicated in the C-OFDMA trigger frame in units of 40 MHz.

[0174] In one embodiment, the C-OFDMA trigger frame includes one or more resource allocation fields corresponding to one or more respective WLANs to participate in C-OFDMA transmission. According to an exemplary embodiment, in the illustrated example, each resource allocation field of the C-OFDMA trigger frame includes: i) an identifier of the BSS (e.g., a 48-bit MAC address of the slave AP, a color ID of the BSS, a 5-bit hash of the MAC address of the slave MAC address, and a 6-bit color ID of the BSS, or another suitable identifier); ii) the frequency bandwidth of the frequency segment used for C-OFDMA transmission; and iii) the first 20 MHz subchannel of the frequency segment. In some embodiments (such as those shown in FIG. 12 ) in which a DL C-OFDMA transmission immediately follows a UL C-OFDMA transmission, the C-OFDMA trigger frame includes: i) an indication of the frequency bandwidth and starting subchannel for the UL C-OFDMA transmission; and ii) an indication of the frequency bandwidth and starting subchannel for the DL C-OFDMA transmission. In other embodiments (such as that shown in FIG. 12) in which a DL C-OFDMA transmission immediately follows a UL C-OFDMA transmission, the C-OFDMA trigger frame includes only one indication of the frequency bandwidth and starting subchannel for both the UL C-OFDMA transmission and the DL C-OFDMA transmission, i.e., the UL C-OFDMA transmission and the DL C-OFDMA transmission use the same frequency segment.

[0175] According to various embodiments, in the case of DL C-OFDMA transmission, each resource allocation field of the C-OFDMA trigger frame further includes one or any suitable combination of two or more of an indicator of the type of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, an indicator of the number of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, a length or duration of a signal field to be included in the PHY preamble of the DL C-OFDMA transmission, an indicator of the duration of the DL C-OFDMA transmission, etc.

[0176] According to various embodiments, for a UL C-OFDMA transmission, each resource allocation field of the C-OFDMA trigger frame further includes one or any suitable combination of two or more of an indication of the type of LTFs to be included in the PHY preamble of the UL C-OFDMA transmission, an indication of the number of LTFs to be included in the PHY preamble of the UL C-OFDMA transmission, an indication of the time length of the UL C-OFDMA transmission, etc. According to various embodiments, in other embodiments where the DL C-OFDMA transmission immediately follows the UL C-OFDMA transmission (such as that shown in FIG. 12), the C-OFDMA trigger frame further includes, in the case of a DL C-OFDMA transmission, one or any suitable combination of two or more of an indication of the type of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the number of LTFs to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the length or duration of a signal field to be included in the PHY preamble of the DL C-OFDMA transmission, an indication of the duration of the DL C-OFDMA transmission, etc.

[0177] In various embodiments, the C-OFDMA trigger frame does not include one or any two of: i) an identifier of the BSS, ii) an indicator of the frequency segment, iii) an indicator of the frequency bandwidth of the frequency segment used for C-OFDMA transmission, iv) a starting 20 MHz subchannel of the frequency segment, v) an indicator of the type of LTF, vi) an indicator of the number of LTFs, vii) an indicator of the length or duration of the signal field, viii) an indicator of the length or duration of the DL C-OFDMA transmission, etc. For example, such information is instead included in the C-OFDMA-A frame.

[0178] In some embodiments, the C-OFDMA trigger frame is transmitted in a 20 MHz wide legacy PPDU (sometimes referred to as a "non-HT PPDU" in the IEEE 802.11 standard), and a replica of the PPDU is transmitted in each 20 MHz subchannel (sometimes referred to as a "non-HT replicated PPDU" in the IEEE 802.11 standard) to generate a full-bandwidth C-OFDMA trigger transmission. As an illustrative example, eight replicas of the C-OFDMA trigger frame are transmitted in eight non-HT replicated PPDUs in eight 20 MHz subchannels to generate a 160 MHz transmission. In some embodiments in which the C-OFDMA trigger frame is transmitted in a non-HT PPDU (i.e., a legacy PPDU), the data rate at which the C-OFDMA trigger frame is transmitted is limited to a data rate from a set of mandatory data rates defined by the communication protocol (e.g., the IEEE 802.11 standard). In some embodiments in which the C-OFDMA trigger frame is transmitted in a non-HT PPDU (i.e., a legacy PPDU), the data rate at which the C-OFDMA trigger frame is transmitted is limited to a data rate from a set of common data rates supported by both the master AP 34 and one or more slave APs 44 involved in the C-OFDMA transmission.

[0179] In other embodiments, the C-OFDMA trigger frame is transmitted in another suitable 20 MHz wide PPDU (e.g., a PPDU compliant with the current draft of the IEEE 802.11ax standard, a PPDU compliant with the IEEE 802.11be standard currently under development, etc.), and a duplicate of the PPDU is transmitted in each 20 MHz subchannel to generate a full-bandwidth C-OFDMA trigger transmission. In some embodiments in which the C-OFDMA trigger frame is transmitted in a PPDU compliant with the IEEE 802.11ax standard or a current draft of the IEEE 802.11be standard currently under development, the MCS and number of spatial streams used to transmit the C-OFDMA trigger frame are limited to the MCS / number of spatial streams combinations defined as mandatory by the IEEE 802.11ax standard / IEEE 802.11be standard. In other embodiments in which the C-OFDMA trigger frame is transmitted in a PPDU compliant with the current draft of the IEEE 802.11ax standard or the IEEE 802.11be standard currently under development, the MCS and number of spatial streams used to transmit the C-OFDMA trigger frame are limited to MCS / number of spatial streams combinations from a set of common MCS / number of spatial streams combinations supported by both the master AP 34 and one or more slave APs 44 involved in the C-OFDMA transmission.

[0180] In another embodiment, the C-OFDMA trigger frame is transmitted in a single PPDU that occupies the complete bandwidth of the C-OFDMA trigger transmission.

[0181] 2-4, in some embodiments, the C-OFDMA-A frame 204 includes an indicator of the duration of the UL ACK / BA transmissions 232 and 236. According to some embodiments, the client station 38 / 48 uses the indicator of the duration of the UL ACK / BA transmissions 232 and 236 to generate the UL ACK / BA transmissions 232 and 236 according to the indicated duration, such that the UL ACK / BA transmissions 232 and 236 end substantially simultaneously (e.g., within 5%). Now, referring to FIG. 2, in some embodiments, the C-OFDMA trigger frame 420 includes an indicator of the duration of the UL ACK / BA transmissions 232 and 236. According to some embodiments, the client station 38 / 48 uses the indicator of the duration of the UL ACK / BA transmissions 232 and 236 to generate the UL ACK / BA transmissions 232 and 236 according to the indicated duration.

[0182] In other embodiments, the C-OFDMA-A frame 204 and the C-OFDMA trigger frame 420 do not include an indicator of the duration of the UL ACK / BA transmissions 860 and / or 864. For example, the UL ACK / BA transmissions 232 and 236 are permitted to have different durations. In some embodiments, an indicator of the duration of the UL ACK / BA transmissions 232 and 236 is included elsewhere, such as in a trigger frame included in the DL C-OFDMA transmissions (212 / 216), such as in the MU-BAR frame 504 / 520.

[0183] 8-10 , in some embodiments, the C-OFDMA-A frame 804 includes an indicator of the duration of the DL ACK / BA transmissions 860 and 864. According to some embodiments, the slave AP 44 uses the indicator of the duration of the DL ACK / BA transmissions 860 and 864 to generate the DL ACK / BA transmission 864 according to the indicated duration, such that the DL ACK / BA transmissions 860 and 864 end substantially simultaneously (e.g., within 5%). Referring now to FIG. 10 , in some embodiments, the C-OFDMA trigger frame 1020 includes an indicator of the duration of the DL ACK / BA transmissions 860 and 864. According to some embodiments, the slave AP 44 uses the indicator of the duration of the DL ACK / BA transmissions 860 and 864 to generate the DL ACK / BA transmission 864 according to the indicated duration, such that the DL ACK / BA transmissions 860 and 864 end substantially simultaneously (e.g., within 5%).

[0184] In other embodiments, the C-OFDMA-A frame 804 and the C-OFDMA trigger frame 1020 do not include an indicator of the time length of the DL ACK / BA transmissions 860 and / or 864. For example, the master AP 34 and the slave AP 44 select a preferred time length for the DL ACK / BA transmissions 860 and 864, e.g., the DL ACK / BA transmissions 860 and 864 are allowed to have different time lengths.

[0185] In some embodiments, an RU assigned to the slave AP 44 for C-OFDMA transmission must include the primary channel of the slave AP 44. In one embodiment, when an RU assigned to the slave AP 44 for C-OFDMA transmission occupies a frequency bandwidth of 160 MHz or less, the RU must include the 20 MHz primary channel of the slave AP 44, and when an RU assigned to the slave AP 44 for C-OFDMA transmission occupies a frequency bandwidth of greater than 160 MHz, the RU must include the 40 MHz primary channel of the slave AP 44. In other embodiments, an RU assigned to the slave AP 44 for C-OFDMA transmission does not need to include the primary channel of the slave AP 44.

[0186] In some embodiments, the master AP 34 and the slave AP 44 have the same primary channel. According to one embodiment, when the master AP 34 and the slave AP 44 have the same primary channel, a target wake-up time (TWT) subchannel selection transmission (SST) is used, in which the AP advertises the channel for client stations to receive trigger frames or downlink multi-user signal fields for C-OFDMA operation. In another embodiment, the master AP 34 advertises schedule information for the master AP 34 and the slave AP 44.

[0187] In another embodiment, the master AP 34 and the slave AP 44 have different primary channels. According to one embodiment, when the master AP 34 and the slave AP 44 have different primary channels, the client stations 38 of the master AP 34 listen to the primary channel of the master AP 34 for RU allocation information for C-OFDMA transmissions, and the client stations 48 of the slave AP 44 listen to the primary channel of the slave AP 44 for RU allocation information for C-OFDMA transmissions.

[0188] In some embodiments, the aggregate communication channel used for C-OFDMA transmission must be included within the operating channel of the master AP 34. In some embodiments, the aggregate communication channel used for C-OFDMA transmission must be included within either the operating channel of the master AP 34 or the operating channel of the slave AP 44. In other embodiments, the aggregate communication channel used for C-OFDMA transmission is required to be included within the operating channel of the master AP 34. In other embodiments, the aggregate communication channel used for C-OFDMA transmission must include both the operating channel of the master AP 34 and the operating channel of the slave AP 44.

[0189] In some embodiments, the master AP 34 is permitted to transmit C-OFDMA-A frames on 20 MHz subchannels that the master AP 34 determines to be idle. In one embodiment, the master AP 34 determining (e.g., the network interface 122 determining, the MAC processor 126 determining, etc.) that a set of subchannels is idle includes: i) determining that a network allocation vector (NAV) timer (e.g., implemented using a timer circuit, a counter circuit, etc., included in the network interface 122, the MAC processor 126, etc.) is zero; ii) determining that a PHY clear channel assessment (CCA) (e.g., implemented using an energy measurement circuit, the PHY processor 130, etc., included in the network interface 122) indicates that a primary subchannel (e.g., a 20 MHz primary channel, a 40 MHz primary channel, etc.) of the master AP 34 is idle; and iii) determining that the PHY CCA is idle within a specified period (e.g., a point coordination function (PCF) interframe space (PIFS) specified by the IEEE 802.11 standard, or another suitable period) for a non-primary subchannel (e.g., a 20 MHz channel, a 40 MHz channel, etc.) before transmission of a C-OFDMA-A frame begins.

[0190] In some embodiments, the slave AP 44 is permitted to transmit (e.g., a trigger frame, DL C-OFDMA transmission, etc.) in response to the slave AP 44 determining that the C-OFDMA-A frame in any of the subchannels assigned to the slave AP 44 by the C-OFDMA-A frame is idle. In one embodiment, the slave AP 44 determining (e.g., by the network interface 122, by the MAC processor 126, etc.) that a set of sub-channels is idle includes determining that the primary sub-channels of the slave AP 44 are idle, including one of: i) determining that the NAV timer is zero; ii) determining that the PHY CCA indicates that a) the primary sub-channels are idle for a predetermined period (e.g., PIFS, or another suitable period) before the transmission of the C-OFDMA-A frame begins; or b) determining that the PHY CCA indicates that the primary sub-channels are idle for a predetermined period (e.g., SIFS, or another suitable period) before the slave AP 44 begins transmission (e.g., of a trigger frame, DL C-OFDMA transmission, etc.); and iii) determining that the PHY CCA indicates that a) the non-primary sub-channels are idle for a predetermined period (e.g., PIFS, or another suitable period) before the transmission of the C-OFDMA-A frame begins. or b) determining that the PHY CCA indicates that the non-primary subchannels are idle for a predetermined period of time (e.g., SIFS or another suitable period of time) before the slave AP 44 begins transmission (e.g., a trigger frame, DL C-OFDMA transmission, etc.).

[0191] In another embodiment, the slave AP 44 transmits (e.g., a trigger frame, a DL C-OFDMA transmission, etc.) in response to the C-OFDMA-A frame on subchannels assigned to the slave AP 44 by the C-OFDMA-A frame without the slave AP 44 first checking whether any of the subchannels are idle. In another embodiment, the C-OFDMA-A frame includes information indicating whether the slave AP 44 determines whether the subchannels are idle before transmitting on them in response to the C-OFDMA-A frame.

[0192] In some embodiments, the master AP 34 sets the time length subfield in the C-OFDMA-A frame to indicate the length of time encompassing the C-OFDMA transmission. In other embodiments where the C-OFDMA-A frame prompts a DL C-OFDMA transmission followed by a UL C-OFDMA transmission (such as the examples of FIGS. 2-4 and 13), the master AP 34 sets the time length subfield in the C-OFDMA-A frame to indicate the length of time that ends before the end of the DL C-OFDMA transmission 208, such as when the trigger frame in the DL C-OFDMA transmission 208 includes information indicating that the client station 38 / 48 checks whether the subchannel is idle before transmitting as part of the UL C-OFDMA transmission. In other embodiments where the C-OFDMA-A frame prompts a DL C-OFDMA transmission followed by a UL C-OFDMA transmission (e.g., the examples of Figures 2-4 and 13), the master AP 34 sets the time length subfield in the C-OFDMA-A frame to indicate the length of time to end before the UL C-OFDMA transmission, such as when the trigger frame in the DL C-OFDMA transmission 208 includes information indicating that the client station 38 / 48 checks whether the subchannel is idle before transmitting as part of the UL C-OFDMA transmission.

[0193] In another embodiment, the client station 38 / 48 is configured to ignore the NAV counter set by the C-OFDMA-A frame when sending a UL C-OFDMA transmission in response to a DL C-OFDMA transmission (sent for the C-OFDMA-A frame). In another embodiment, the client station 48 is configured to ignore the NAV counter set by the C-OFDMA-A frame when the C-OFDMA-A is addressed to the slave AP 44 with which the client station 48 is associated.

[0194] In other embodiments in which a C-OFDMA-A frame prompts a UL C-OFDMA transmission (e.g., the examples of FIGS. 2-4 and 13), such as when a trigger frame in a DL C-OFDMA transmission 208 includes information indicating that the client station 38 / 48 checks whether the subchannel is idle before transmitting as part of the UL C-OFDMA transmission, the master AP 34 sets the time length subfield in the C-OFDMA-A frame to indicate the length of time to end before the end of the DL C-OFDMA transmission 208. In other embodiments in which a C-OFDMA-A frame prompts a DL C-OFDMA transmission that is followed by a UL C-OFDMA transmission (e.g., the examples of FIGS. 8-12), the master AP 34 sets the time length subfield in the C-OFDMA-A frame to indicate the length of time to end before the UL C-OFDMA transmission. In one embodiment, the master AP 34 sets the duration subfield in the C-OFDMA-A frame to indicate the duration that ends before the end of the DL OFDMA transmission that includes the trigger frame prompting the UL C-OFDMA transmission.

[0195] In another embodiment, the client station 38 / 48 is configured to ignore the NAV counter set by the C-OFDMA-A frame when sending a UL C-OFDMA transmission in response to the C-OFDMA-A frame. In another embodiment, the client station 48 is configured to ignore the NAV counter set by the C-OFDMA-A frame when the C-OFDMA-A is addressed to the slave AP 44 with which the client station 48 is associated.

[0196] In some embodiments, the client station 38 / 48 maintains a first NAV counter (intra-BSS NAV counter) for intra-BSS transmissions (e.g., for transmissions within a WLAN or BSS to which the client station 38 / 48 belongs) and a second NAV counter (inter-BSS NAV counter) for inter-BSS transmissions (e.g., for transmissions from a WLAN or BSS to which the client station 38 / 48 does not belong). In one embodiment, when the client station 48 receives a C-OFDMA-A frame from the master AP 34 (and the client station is not associated with the master 34), the client station 48 determines (e.g., by the network interface 162, by the MAC processor 166, etc.) whether the C-OFDMA-A frame includes a network identifier (e.g., a MAC address, BSS ID, or another suitable identifier) ​​of the slave AP 44 with which the client station 48 is associated among a set of network identifiers indicating the slave APs 44 involved in the C-OFDMA transmission. When the C-OFDMA-A frame includes the network identifier of the slave AP 44 with which the client station 48 is associated, the client station 48 uses the time length information in the C-OFDMA-A frame to set the intra-BSS NAV counter (e.g., set by the network interface 162, set by the MAC processor 166, etc.).

[0197] In some embodiments, prior to a C-OFDMA transmission, the slave AP 44 transmits resource request information for the C-OFDMA transmission to the master AP 34. In various embodiments, the resource request information includes one or any suitable combination of two or more of an indication of a requested frequency bandwidth, an indication of a requested duration of a PPDU to be transmitted during the C-OFDMA transmission, an indication of the type of LTFs to be included in the PPDU, an indication of the number of LTFs to be included in the PPDU, an indication of a requested duration of a signal field to be included in the PPDU (when the PPDU is part of a DL C-OFDMA transmission), etc. In one embodiment, the slave AP 44 is configured (e.g., the network interface 122 is configured, the MAC processor 126 is configured, the C-OFDMA controller is configured, etc.) to generate a frame including the resource request information, and the slave AP 44 is configured (e.g., the network interface 122 is configured, the PHY processor 130 is configured, etc.) to transmit the frame in a packet to the master AP 34.

[0198] In some embodiments, the slave AP 44 is configured to contend for the wireless communication medium and transmit resource request information to the master AP 34 in response to obtaining the wireless communication medium.

[0199] In another embodiment, the master AP 34 is configured to poll the slave APs 44 for resource request information. For example, the master AP 34 generates and transmits a trigger frame (e.g., a resource request trigger) to the slave AP 44, where the trigger frame is configured to prompt the slave AP 44 to transmit resource request information to the master AP 34. In one embodiment, the resource request trigger includes, for each of one or more slave APs 44, a network identifier of the slave AP 44. According to one embodiment, when the slave AP 44 receives the resource request trigger, the slave AP 44 determines whether the network ID of the slave AP 44 is included in the resource request trigger, and if the network ID of the slave AP 44 is included in the resource request trigger, the slave AP 44 transmits the resource request information to the master AP 34.

[0200] In one embodiment, the network ID of the slave AP 44 includes the MAC address of the slave AP 44. In another embodiment, the network ID of the slave AP 44 includes the BSS ID corresponding to the slave AP 44. In another embodiment, the network ID of the slave AP 44 includes a hash value generated by applying a known hash function to the MAC address of the slave AP 44. In various embodiments, the hash value has a length of 11 bits or another suitable number of bits.

[0201] In another embodiment, the network ID of the slave AP 44 includes i) the BSS Color ID of the slave AP 44 (or a subset of the bits of the BSS Color ID (e.g., 6 bits of the BSS Color ID)), and ii) bits (e.g., 5 bits, 6 bits) obtained or generated from the MAC address of the slave AP 44 (e.g., by applying a hash function to the MAC address).

[0202] The master AP 34 analyzes the resource request information received from the slave AP 44 and determines the allocation of frequency segments to the master AP 34 and the slave AP 44 based on the resource request information received from the slave AP 44. In some embodiments, the master AP 34 analyzes the resource request information received from the slave AP 44 and determines the duration of C-OFDMA transmission (e.g., DL C-OFDMA transmission, UL C-OFDMA transmission) based on the resource request information received from the slave AP 44.

[0203] In some embodiments, the master AP 34 analyzes the resource request information received from the slave AP 44 and determines whether a cascaded C-OFDMA operation (e.g., a DL C-OFDMA transmission followed by a UL C-OFDMA transmission in FIG. 13, a UL C-OFDMA transmission followed by a DL C-OFDMA transmission in FIG. 12, etc.) should be allocated based on the resource request information received from the slave AP 44.

[0204] In some embodiments, an AP advertises whether it supports C-OFDMA transmissions (e.g., in a management frame (or another suitable management frame), such as a beacon frame or a probe response frame, in a frame addressed to neighboring APs, etc.). In some embodiments, the AP also advertises (e.g., in the same frame or a different frame) whether it supports a master role and / or whether it supports a slave role.

[0205] In some embodiments, the APs negotiate which AP will be the master AP and which AP will be the slave AP by exchanging frames (e.g., public action frames or other suitable frames), and the APs retain the same roles until renegotiated.

[0206] In another embodiment, the AP that gains access to the channel medium automatically becomes the master AP and notifies other APs (e.g., via a public action frame, a management frame (e.g., a beacon frame, a probe response frame, etc.), or another suitable frame) that they may participate in C-OFDMA transmissions as slave APs.

[0207] In an embodiment where the master AP 34 and the slave APs 44 are part of an extended service set (ESS), the master AP 34 is configured to schedule one or more (C-OFDMA transmission capable) APs 44 for C-OFDMA transmission. In another embodiment, a first AP notifies a second AP (e.g., via a management frame or another suitable frame) whether the second AP is permitted to schedule the first AP for C-OFDMA transmission.

[0208] In one embodiment, APs are configured to form static groups of APs configured to participate in C-OFDMA transmissions. According to one embodiment, for example, APs in an ESS configured to participate in C-OFDMA transmissions form groups implicitly. In another embodiment, APs negotiate to form groups, for example, by exchanging management frames. According to one embodiment, once a group is formed, any AP in the group can act as a master AP 34, for example, to initiate C-OFDMA transmissions and assign frequency RUs to other APs (acting as slave APs 44) for C-OFDMA transmissions.

[0209] While the examples described above involve an AP transmitting to multiple client stations or multiple client stations transmitting to an AP as part of a C-OFDMA transmission, in some embodiments, an AP transmits to a single client station, or a single client station transmits to an AP, as part of a C-OFDMA transmission.

[0210] While the examples described above involve cooperative OFDMA transmission, in other embodiments, the packet switching techniques, etc., described above additionally or alternatively utilize cooperative MU-MIMO transmission. For example, as part of a cooperative DL transmission, the master AP 34 may transmit in a frequency segment using one or more first spatial streams, while the slave AP 44 transmits in the same frequency segment using one or more second spatial streams. In another example, as part of a cooperative UL transmission, one or more client stations 38 of the master AP 34 may transmit in a frequency segment using one or more first spatial streams, while one or more client stations 48 of the slave AP 44 transmit in the same frequency segment using one or more second spatial streams. Thus, the exemplary C-OFDMA packet switching techniques, etc., described above are merely exemplary embodiments of cooperative multi-user (MU) transmission and related techniques. In other embodiments, the cooperative MU transmission includes cooperative MU-MIMO transmission. Similarly, the C-OFDMA-A frame described above is merely an illustrative example of an indication frame indicating a cooperative multi-user (MU) transmission, which may be used, for example, in connection with a C-OFDMA transmission and a cooperative MU-MIMO transmission. Similarly, the C-OFDMA trigger frame described above is merely an illustrative example of a trigger frame for use in a cooperative MU transmission, which may be used, for example, in connection with a C-OFDMA transmission and a cooperative MU-MIMO transmission. Similarly, the C-OFDMA controllers 60 / 70 / 80 described above are merely illustrative examples of controllers for use in a cooperative MU transmission, which may be used, for example, in connection with a C-OFDMA transmission and a cooperative MU-MIMO transmission.

[0211] While the examples described above involve synchronized transmissions by or to multiple APs starting substantially simultaneously, in other embodiments, exemplary packet switching techniques, etc. are modified to allow transmissions by or to different APs to start at different times. Similarly, while the examples described above involve synchronized transmissions by or to multiple APs ending substantially simultaneously, in other embodiments, exemplary packet switching techniques, etc. are modified to allow transmissions by or to different APs to end at different times. For example, in exemplary embodiments, transmissions by or to different APs overlap in time and occur during the same time window, but do not necessarily start substantially simultaneously and / or do not necessarily end substantially simultaneously.

[0212] Figure 14 is a flow diagram of an example method 1400 for wireless communication involving multiple APs, according to one embodiment. Method 1400 is implemented by a master AP having a structure such as that described in connection with Figure 1B, and Figure 14 is described in connection with Figure 1B for ease of explanation. In other embodiments, however, method 1400 is implemented by an AP having a suitable structure different from that shown in Figure 1B.

[0213] In various embodiments, the method 1400 is utilized in connection with any of the frame exchanges described in connection with any of FIGS. 2 through 13 and / or in connection with any of the techniques described above.

[0214] The method 1400 is implemented by a master AP associated with one or more first client stations.

[0215] At block 1404, the master AP generates (e.g., generated by network interface 122, generated by MAC processor 126, generated by controller 60, etc.) announcing a cooperative MU transmission (e.g., C-OFDMA transmission, cooperative MU-MIMO transmission, etc.) involving multiple APs, including the master AP and one or more slave APs (each of the slave APs is associated with a respective one or more second client stations). In one embodiment, the notification frame generated at block 1404 indicates one or more frequency RUs assigned to the one or more slave APs for the cooperative MU transmission.

[0216] At block 1408, the master AP transmits an announcement frame to one or more slave APs (eg, via the network interface 122, via the PHY processor 130, etc.) to initiate a cooperative MU transmission.

[0217] At block 1412, the master AP engages in cooperative MU transmissions, while one or more secondary APs engage in cooperative MU transmissions.

[0218] In some embodiments, engaging in a cooperative MU transmission at block 1412 includes the master AP transmitting a first DL transmission to at least one first client station among one or more first client stations, while one slave AP transmits a second DL transmission to at least one second client station among one or more second client stations (e.g., the network interface 122 transmitting, the PHY processor 130 transmitting, etc.).

[0219] In some embodiments, notifying the generated frame includes generating a notification frame to indicate that one slave AP has been assigned a first frequency RU, and transmitting a first DL transmission as part of engaging in cooperative MU transmission in block 1412 includes transmitting a first DL transmission in a second frequency RU, while the one slave AP transmits a second DL transmission in the first RU, the second RU not overlapping in frequency with the first frequency RU.

[0220] In some embodiments, generating a notification frame in block 1404 includes generating a notification frame to indicate that one slave AP has been assigned a first frequency RU and one or more first spatial streams, and transmitting a first DL transmission as part of engaging in cooperative MU transmission in block 1412 includes transmitting the first DL transmission in the first frequency RU using one or more second spatial streams, while the one slave AP transmits a second DL transmission in the first frequency RU using one or more first spatial streams.

[0221] In some embodiments, generating the notification frame at block 1404 includes generating the notification frame to include an indication of a time length of a signal field to be included in the PHY header of the second DL transmission, and method 1400 further includes the master AP generating the first DL transmission to include a signal field in the PHY header of the first DL transmission, wherein the signal field in the PHY header of the first DL transmission has a time length of the signal field in the PHY header of the second DL transmission.

[0222] In some embodiments, engaging in a cooperative MU transmission at block 1412 includes the master AP transmitting a first trigger frame to at least one first client station among the one or more first client stations, while the one slave AP transmitting a second trigger frame to at least one second client station among the one or more second client stations, and receiving a first UL transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the one slave AP in response to the second trigger frame.

[0223] In some embodiments, generating a notification frame in block 1404 includes generating a notification frame to indicate that a first frequency RU has been assigned to one second AP, and engaging in cooperative MU transmission in block 1412 includes receiving a first UL transmission in a second frequency RU, while at least one second client station transmits a second UL transmission in the first RU, where the second RU does not overlap in frequency with the first frequency RU.

[0224] In some embodiments, generating the notification frame in block 1404 includes generating the notification frame to indicate that one slave AP has been assigned a first frequency RU and one or more first spatial streams, and engaging in cooperative MU transmission in block 1412 includes receiving a first UL transmission in the first frequency RU via one or more second spatial streams, while at least one second client station transmits a second UL transmission in the first RU via one or more first spatial streams.

[0225] In some embodiments, generating the notification frame at block 1404 includes generating the notification frame to include an indication of the time length of the second trigger frame, and engaging in cooperative MU transmission at block 1412 includes the master AP generating the first trigger frame to have the time length of the second trigger frame.

[0226] In some embodiments, the method 1400 further includes the master AP receiving resource request information from one or more slave APs, and the master AP allocating one or more frequency RUs to the one or more slave APs for cooperative MU transmissions based on the resource request information from the one or more second APs.

[0227] 15 is a flow diagram of another exemplary method 1500 for wireless communication involving multiple APs, according to another embodiment. Method 1500 is implemented by a slave AP having a structure such as that described in connection with FIG. 1B, and FIG. 15 is described in connection with FIG. 1B for ease of explanation. In other embodiments, however, method 1500 is implemented by an AP having a suitable structure different from that shown in FIG. 1B.

[0228] In various embodiments, the method 1500 is utilized in connection with any of the frame exchanges described with respect to any of FIGS. 2-13 and / or in connection with any of the techniques described above.

[0229] The method 1500 is implemented by a slave AP associated with one or more first client stations.

[0230] At block 1504, the slave AP receives an announcement frame from the master AP associated with one or more second client stations (e.g., received by network interface 122, received by MAC processor 126, received by controller 70, etc.). In one embodiment, the announcement frame announces a cooperative MU transmission (e.g., C-OFDMA transmission, cooperative MU-MIMO transmission, etc.) involving at least the slave AP and the master AP. In one embodiment, the announcement frame includes an indicator of a frequency RU assigned to the slave AP for the cooperative MU transmission.

[0231] In block 1508, the slave AP engages in cooperative MU transmission using the frequency RU indicated by the announcement frame, while the slave AP engages in cooperative MU transmission.

[0232] In one embodiment, engaging in a cooperative MU transmission at block 1508 includes the slave AP transmitting a first DL transmission to at least one first client station among one or more first client stations (e.g., the network interface device 122 transmitting, the PHY processor 130 transmitting, etc.), while the master AP transmitting a second DL transmission to at least one second client station among one or more second client stations.

[0233] In some embodiments, method 1500 further includes the slave AP determining a first frequency RU based on an indicator of the RU assigned to the slave AP in the notification frame (e.g., determined by the network interface device 122, determined by the MAC processor 126, determined by the controller 70, etc.), and engaging in cooperative MU transmission in block 1508 includes transmitting a first DL transmission on the first frequency RU, while the second AP transmits a second DL transmission on a second frequency RU, wherein the second frequency RU does not overlap in frequency with the first frequency RU.

[0234] In some embodiments, the method 1500 further includes the slave AP determining a first frequency RU based on an indicator of an RU assigned to the slave AP in the notification frame (e.g., determined by the network interface device 122, determined by the MAC processor 126, determined by the controller 70, etc.), and the slave AP determining one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for cooperative MU transmission in the notification frame (e.g., determined by the network interface device 122, determined by the MAC processor 126, determined by the controller 70, etc.), wherein engaging in cooperative MU transmission in block 1508 includes transmitting a first DL transmission in the first frequency RU using the one or more first spatial streams, while the second AP transmitting a second DL transmission in the first frequency RU using one or more second spatial streams.

[0235] In some embodiments, method 1500 further includes the slave AP determining (e.g., by the network interface device 122, by the MAC processor 126, by the controller 70, etc.) the time length of the signal field (the signal field to be included in the physical layer (PHY) header in the first DL transmission) based on an indicator of the signal field time length for the cooperative MU transmission in the notification frame, and engaging in the cooperative MU transmission in block 1508 includes the slave AP generating (e.g., by the network interface device 122, by the PHY processor 130, etc.) the first DL transmission to include the signal field having the time length in the PHY header of the first DL transmission.

[0236] In some embodiments, engaging in the cooperative MU transmission in block 1508 includes the slave AP transmitting a first trigger frame to at least one first client station among the one or more first client stations (e.g., the network interface device 122 transmitting, the PHY processor 130 transmitting, etc.), while the master AP transmitting a second trigger frame to at least one second client station among the one or more second client stations, and the slave AP receiving a first UL transmission from the at least one first client station (e.g., the network interface device 122 receiving, the PHY processor 130 receiving, etc.), while the at least one second client station transmitting a second UL transmission to the master AP in response to the second trigger frame.

[0237] In some embodiments, the method 1500 further includes the slave AP determining (e.g., by the network interface device 122, by the MAC processor 126, by the controller 70, etc.) a first frequency RU based on an indicator of the RU assigned to the first AP in the notification frame, and engaging in cooperative MU transmission in block 1508 includes transmitting a first trigger frame in the first frequency RU while the master AP transmits a second trigger frame in a second frequency RU (the second frequency RU does not overlap in frequency with the first frequency RU), and receiving the first UL transmission in the first frequency RU while at least one second client station transmits a second UL transmission in the second RU.

[0238] In some embodiments, the method 1500 further includes the slave AP determining a first frequency RU based on an indicator of the RU assigned to the first AP in the notification frame (e.g., determined by the network interface device 122, determined by the MAC processor 126, determined by the controller 70, etc.), and the slave AP determining one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for cooperative MU transmission in the notification frame (e.g., determined by the network interface device 122, determined by the MAC processor 126, determined by the controller 70, etc.), and the slave AP generating a first trigger frame (e.g., generated by the network interface device 122, generated by the MAC processor 126, etc.) to instruct one or more first client stations to transmit during a first UL transmission in the first frequency RU via the one or more first spatial streams. In some embodiments, engaging in a cooperative MU transmission in block 1508 includes the slave AP receiving a first UL transmission in a first frequency RU via one or more first spatial streams, while at least one second client station transmits a second UL transmission in the first RU via one or more second spatial streams.

[0239] In some embodiments, method 1500 further includes the slave AP determining a time length of the first trigger frame based on an indicator of the time length of the first trigger frame in the notification frame (e.g., determined by network interface device 122, determined by MAC processor 126, determined by controller 70, etc.), and the slave AP generating (e.g., generated by network interface device 122, generated by MAC processor 126, etc.) the first trigger frame to have the determined time length.

[0240] In some embodiments, the method 1500 further includes, before receiving the notification frame, the slave AP generating (e.g., generated by the network interface device 122, generated by the MAC processor 126, etc.) resource request information to request an RU for cooperative MU transmission, and the slave AP transmitting (e.g., transmitted by the network interface device 122, transmitted by the PHY processor 130, etc.) the resource request information to the second AP.

[0241] 16 is a flow diagram of another exemplary method 1600 for wireless communication involving multiple APs, according to another embodiment. Method 1600 is implemented by a master AP having a structure such as that described in connection with FIG. 1B, and FIG. 16 is described in connection with FIG. 1B for ease of explanation. In other embodiments, however, method 1600 is implemented by an AP having a suitable structure different from that shown in FIG. 1B.

[0242] In various embodiments, the method 1600 is utilized in connection with any of the frame exchanges described with respect to any of FIGS. 2-13 and / or in connection with any of the techniques described above.

[0243] In block 1604, the first AP determines (e.g., by the network interface 122, by the MAC processor 126, by the controller 60, etc.) that the first AP is the master AP for cooperative MU transmission (e.g., C-OFDMA transmission, cooperative MU-MIMO transmission, etc.) involving multiple APs including the first AP acting as a slave AP and one or more second APs.

[0244] In block 1608, the first AP receives resource request information from one or more second APs regarding access to the wireless communication medium by the one or more second APs for cooperative MU transmission (e.g., received by the network interface 122, received by the MAC processor 126, received by the controller 60, etc.).

[0245] In block 1612, the first AP allocates frequency RUs to the first AP and one or more second APs for cooperative MU transmissions based on the resource request information received in block 1608 (e.g., allocated by the network interface 122, allocated by the MAC processor 126, allocated by the controller 60, etc.).

[0246] In block 1616, the first AP generates a notification frame regarding the cooperative MU transmission (e.g., generated by the network interface 122, generated by the MAC processor 126, generated by the controller 60, etc.). In one embodiment, the notification frame includes allocation information regarding RUs allocated to one or more second APs for the cooperative MU transmission.

[0247] In block 1620, the first AP transmits (e.g., by the network interface 122, by the PHY processor 130, etc.) a notification frame to provide allocation information to one or more second APs regarding RUs allocated to the one or more second APs.

[0248] At block 1624, the first AP engages in cooperative MU transmission, while one or more second APs engage in cooperative MU transmission.

[0249] In some embodiments, receiving resource request information from one of the second APs in block 1608 includes the first AP receiving a packet from the one second AP (the packet being transmitted in response to the second AP contending for the wireless communication medium to transmit the packet) and acquiring the wireless communication medium. In one embodiment, the packet includes the resource request information from the one second AP.

[0250] In some embodiments, method 1600 further includes the first AP generating (e.g., generated by network interface 122, generated by MAC processor 126, generated by controller 60, etc.) a trigger frame configured to prompt at least one second AP among the one or more second APs to transmit resource request information, and the first AP transmitting (e.g., transmitted by network interface 122, transmitted by PHY processor 130, etc.) the trigger frame to prompt the at least one second AP to transmit the resource request information. In one embodiment, receiving the resource request information at block 1608 includes receiving the resource request information from the at least one second AP in response to transmitting the trigger frame.

[0251] In some embodiments, generating the trigger frame includes including an identifier of one second AP in the trigger frame, and receiving resource request information in block 1608 includes receiving resource request information from the one second AP.

[0252] In some embodiments, the identifier of the one second AP in the trigger frame includes a MAC address of the one second AP. In other embodiments, the identifier of the one second AP in the trigger frame includes a first set of bits from a BSS color identifier of the one second AP and a second set of bits generated from the MAC address of the one second AP. In one embodiment, the second set of bits generated from the MAC address of the one second AP includes a set of bits generated by applying a hash function to the MAC address of the one second AP.

[0253] In some embodiments, receiving resource request information in block 1608 includes receiving from the one second AP an indicator of a frequency bandwidth requested by the one second AP for the cooperative MU transmission.

[0254] In some embodiments, receiving resource request information in block 1608 includes receiving an indicator of a time length of packets transmitted during a cooperative MU transmission from one of the second APs.

[0255] In some embodiments, receiving resource request information at block 1608 includes receiving, from one second AP, an indicator of a time length of a signal field in a PHY header of a packet transmitted during a cooperative MU transmission.

[0256] 17 is a flow diagram of another exemplary method 1700 for wireless communication involving multiple APs, according to another embodiment. Method 1700 is implemented by a client station having a structure such as that described in connection with FIG. 1C, and for ease of explanation, FIG. 17 is described in connection with FIG. 1C. However, in other embodiments, method 1700 is implemented by a client station having a suitable structure different from that shown in FIG. 1C.

[0257] In various embodiments, the method 1700 is utilized in connection with any of the frame exchanges described in connection with any of FIGS. 2-13 and / or in connection with any of the techniques described above.

[0258] The method 1700 is implemented by a client station associated with a first AP.

[0259] At block 1704, the client station receives an announcement frame transmitted by a second AP with which the client station is not associated (e.g., received by network interface 162, received by MAC processor 166, received by controller 80, etc.). The announcement frame announces a cooperative MU transmission involving the second AP and one or more other APs. The announcement frame includes one or more respective network identifiers of the one or more other APs, and the announcement frame further includes a time length field indicating a time length corresponding to the cooperative MU transmission.

[0260] In block 1708, in response to receiving the notification frame, the client station sets the client station's NAV counter based on the value of the duration field in the notification frame (e.g., set by the network interface 162, set by the MAC processor 166, set by the controller 80, etc.).

[0261] At block 1712, the client station determines that the announcement frame includes the network identifier of the first AP (eg, the network interface 162 determines, the MAC processor 166 determines, the controller 80 determines, etc.).

[0262] In block 1716, the client station determines (e.g., the network interface 162 determines, the MAC processor 166 determines, the controller 80 determines, etc.) that the client station will transmit on the communication channel to the first AP as part of a cooperative MU transmission.

[0263] In block 1720, the client station determines that the communication channel is idle (e.g., determined by the network interface 162, determined by the MAC processor 166, determined by the controller 80, etc.) and, in response to the notification frame including the network identifier of the first AP, in response to determining that the NAV counter is set, includes ignoring the NAV counter.

[0264] At block 1724, the client station transmits (eg, network interface 162 transmits, PHY processor 170 transmits, etc.) as part of a cooperative MU transmission in response to determining that the communication channel is idle.

[0265] In some embodiments, the collaborative MU transmission includes respective downlink transmissions by the first AP and the second AP, and in block 1724, transmitting as part of the collaborative MU transmission includes transmitting to the first AP after the respective downlink transmissions by the first AP and the second AP.

[0266] In some embodiments, the method 1700 further includes the client station maintaining (e.g., by the network interface 162, by the MAC processor 166, etc.) a first NAV counter for transmissions in a basic service set (BSS) managed by the first AP, and the client station maintaining (e.g., by the network interface 162, by the MAC processor 166, etc.) a second NAV counter for transmissions not within a BSS managed by the first AP, and setting the NAV counter of the client station based on the value of the time length field in the notification frame includes the client station setting (e.g., by the network interface 162, by the MAC processor 166, etc.) the first NAV counter in response to determining that the notification frame transmitted by the second AP includes a network identifier of the first AP.

[0267] Embodiment 1: A method for wireless communication by a first access point (AP) associated with one or more first client stations, the method comprising: generating, at the first AP, a notification frame announcing a cooperative multi-user (MU) transmission involving a plurality of APs, including the first AP and one or more second APs, each of the second APs being associated with a respective one or more second client stations, the notification frame being generated to indicate a respective one or more frequency resource units (RUs) allocated to the one or more second APs for the cooperative MU transmission; transmitting, by the first AP, the notification frame to the one or more second APs to initiate the cooperative MU transmission; and engaging in the cooperative MU transmission by the first AP, while the one or more second APs also engage in the cooperative MU transmission.

[0268] Embodiment 2: The method of embodiment 1, wherein engaging in cooperative MU transmission includes sending, by a first AP, a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while a second AP sends a second DL transmission to at least one second client station among the one or more second client stations.

[0269] Embodiment 3: The method of embodiment 2, wherein the step of generating a notification frame includes a step of generating a notification frame to indicate that one second AP is assigned to the first frequency RU, and the step of transmitting a first DL transmission includes a step of transmitting a first DL transmission in a second frequency RU, while the one second AP transmits a second DL transmission in the first RU, and the second RU does not overlap in frequency with the first frequency RU.

[0270] Embodiment 4: The method of embodiment 2, wherein the step of generating a notification frame includes a step of generating a notification frame to indicate that one second AP has been assigned a first frequency RU and one or more first spatial streams, and the step of transmitting a first DL transmission includes a step of transmitting the first DL transmission in the first frequency RU using one or more second spatial streams, while the one second AP transmits a second DL transmission in the first frequency RU using one or more first spatial streams.

[0271] Embodiment 5: A method as described in any of embodiments 2 to 4, wherein the step of generating a notification frame includes a step of generating the notification frame to include an indication of the time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission, and a step of generating, at the first AP, a first DL transmission to include a signal field in the PHY header of the first DL transmission, wherein the signal field in the PHY header of the first DL transmission has the time length of the signal field in the PHY header of the second DL transmission.

[0272] Embodiment 6: The method of embodiment 1, wherein the step of engaging in cooperative MU transmission includes: transmitting, by a first AP, a first trigger frame to at least one first client station among one or more first client stations, while a second AP transmits a second trigger frame to at least one second client station among one or more second client stations; and receiving, at the first AP, a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the second AP in response to the second trigger frame.

[0273] Embodiment 7: The method of embodiment 6, wherein the step of generating a notification frame includes a step of generating a notification frame to indicate that a first frequency RU has been assigned to one second AP, and the step of receiving a first UL transmission includes a step of receiving the first UL transmission in a second frequency RU, while at least one second client station transmits a second UL transmission in the first RU, and the second RU does not overlap in frequency with the first frequency RU.

[0274] Embodiment 8: The method of embodiment 6, wherein the step of generating a notification frame includes a step of generating a notification frame to indicate that one second AP has been assigned a first frequency RU and one or more first spatial streams, and the step of receiving a first UL transmission includes a step of receiving a first UL transmission in the first frequency RU via one or more second spatial streams, while at least one second client station transmits a second UL transmission in the first RU via one or more first spatial streams.

[0275] Embodiment 9: A method as described in any of embodiments 6 to 8, wherein the step of generating a notification frame includes a step of generating the notification frame to include an indication of the time length of the second trigger frame, and the step of participating in cooperative MU transmission includes a step of generating a first trigger frame at the first AP to have the time length of the second trigger frame.

[0276] Embodiment 10: The method of any one of embodiments 1 to 9, further comprising: receiving, in the first AP, resource request information from one or more second APs; and allocating, in the first AP, one or more frequency RUs to one or more second APs for cooperative MU transmission based on the resource request information from the one or more second APs.

[0277] Embodiment 11: A method as described in any one of embodiments 1 to 10, further comprising, after transmitting the notification frame, receiving, at the first AP, one or more respective copies of the notification frame from one or more second APs, and transmitting, by the first AP, a further copy of the notification frame simultaneously with receiving the one or more respective copies of the notification frame.

[0278] Embodiment 12: The method of embodiment 11, further comprising, after receiving one or more respective copies of the notification frame, sending a trigger frame by the first AP to one or more second APs to further initiate cooperative MU transmission.

[0279] Embodiment 13: A first access point (AP) associated with one or more first client stations, the first AP comprising a wireless network interface device including one or more integrated circuit (IC) devices, the one or more IC devices configured to: generate an announcement frame announcing a cooperative multi-user (MU) transmission involving multiple APs, including the first AP and one or more second APs, each of the second APs associated with a respective one or more second client stations, the announcement frame being generated to indicate a respective one or more frequency resource units (RUs) allocated to the one or more second APs for the cooperative MU transmission; control the wireless network interface device to send the announcement frame to the one or more second APs to initiate the cooperative MU transmission; and control the wireless network interface device to engage in the cooperative MU transmission, while the one or more second APs also engage in the cooperative MU transmission.

[0280] Embodiment 14: A first AP as described in embodiment 13, wherein one or more IC devices are configured to at least control the wireless network interface device to transmit a first downlink (DL) transmission to at least one first client station among one or more first client stations, while one second AP is configured to control the wireless network interface device to engage in cooperative MU transmission by transmitting a second DL transmission to at least one second client station among one or more second client stations.

[0281] Embodiment 15: A first AP as described in embodiment 14, wherein one or more IC devices are configured to generate a notification frame to indicate that a first frequency RU has been assigned to one second AP, and to control a wireless network interface device to transmit a first DL transmission in the second frequency RU, while the one second AP transmits a second DL transmission in the first RU, and the second RU does not overlap in frequency with the first frequency RU.

[0282] Embodiment 16: A first AP as described in embodiment 14, wherein one or more IC devices are configured to generate a notification frame to indicate that one second AP has been assigned a first frequency RU and one or more first spatial streams, and to control a wireless network interface device to transmit a first DL transmission in the first frequency RU using one or more second spatial streams, while the one second AP transmits a second DL transmission in the first frequency RU using one or more first spatial streams.

[0283] Embodiment 17: A first AP described in any of embodiments 14 to 16, wherein one or more IC devices are configured to generate a notification frame to include an indication of the time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission, and to generate a first DL transmission to include a signal field in the PHY header of the first DL transmission, wherein the signal field in the PHY header of the first DL transmission has the time length of the signal field in the PHY header of the second DL transmission.

[0284] Embodiment 18: The first AP described in embodiment 13, wherein one or more IC devices are configured to control the wireless network interface device to engage in cooperative MU transmission by at least controlling the wireless network interface device to transmit a first trigger frame to at least one first client station among one or more first client stations, while the one second AP transmits a second trigger frame to at least one second client station among one or more second client stations, and receiving a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the one second AP in response to the second trigger frame.

[0285] Embodiment 19: A first AP as described in embodiment 18, wherein one or more IC devices are configured to generate a notification frame to indicate that a first frequency RU has been assigned to one second AP, and to receive a first UL transmission in the second frequency RU, while at least one second client station transmits a second UL transmission in the first RU, and the second RU does not overlap in frequency with the first frequency RU.

[0286] Embodiment 20: A first AP as described in embodiment 18, wherein one or more IC devices are configured to generate a notification frame to indicate that a first frequency RU and one or more first spatial streams have been assigned to one second AP, and to receive a first UL transmission in the first frequency RU via one or more second spatial streams, while at least one second client station transmits a second UL transmission in the first RU via one or more first spatial streams.

[0287] Embodiment 21: A first AP described in any of embodiments 18 to 20, wherein one or more IC devices are configured to generate a notification frame to include an indication of the time length of the second trigger frame, and to generate a first trigger frame to have the time length of the second trigger frame.

[0288] Embodiment 22: The first AP described in any of embodiments 13 to 21, wherein the one or more IC devices are further configured to receive resource request information from one or more second APs, and allocate one or more frequency RUs to the one or more second APs for cooperative MU transmission based on the resource request information from the one or more second APs.

[0289] Embodiment 23: A first AP described in any of embodiments 13 to 22, wherein the one or more IC devices are further configured to, after transmitting the notification frame, receive one or more respective copies of the notification frame from one or more second APs, and control the wireless network interface device to transmit further copies of the notification frame simultaneously with receiving one or more respective copies of the notification frame from the one or more second APs.

[0290] Embodiment 24: The first AP described in embodiment 23, wherein the one or more IC devices are further configured to control the wireless network interface device to send a trigger frame to one or more second APs to initiate further cooperative MU transmissions after receiving one or more respective copies of the notification frame.

[0291] Embodiment 25: A method for wireless communication by a first access point (AP) associated with one or more first client stations, the method comprising: receiving, at the first AP, an announcement frame from a second AP associated with one or more second client stations, the announcement frame announcing a cooperative multi-user (MU) transmission involving at least the first AP and the second AP, the announcement frame including an indicator of a frequency resource unit (RU) allocated to the first AP for the cooperative MU transmission; and engaging in the cooperative MU transmission by the first AP using a frequency RU indicated by the announcement frame, while the second AP also engages in the cooperative MU transmission.

[0292] Embodiment 26: The method of embodiment 25, wherein the step of engaging in cooperative MU transmission includes a step of transmitting, by a first AP, a first downlink (DL) transmission to at least one first client station among one or more first client stations, while the second AP transmits a second DL transmission to at least one second client station among one or more second client stations.

[0293] Embodiment 27: The method of embodiment 26 further includes a step in which, in the first AP, a step of determining a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame, and the step of transmitting a first DL transmission includes a step of transmitting the first DL transmission in the first frequency RU, while the second AP transmits the second DL transmission in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU.

[0294] Embodiment 28: The method of embodiment 26 further comprises: at the first AP, determining a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame; and at the first AP, determining one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for cooperative MU transmission in the notification frame, wherein the step of transmitting the first DL transmission includes transmitting the first DL transmission in the first frequency RU using one or more first spatial streams, while the second AP includes transmitting the second DL transmission in the first frequency RU using one or more second spatial streams.

[0295] Embodiment 29: A method according to any of embodiments 26 to 28, further comprising: a step of determining, in the first AP, a time length of a signal field based on an indicator of a signal field time length for a cooperative MU transmission in the notification frame, wherein the signal field is to be included in a physical layer (PHY) header in the first DL transmission; and a step of generating, in the first AP, a first DL transmission so as to include a signal field having the time length in the PHY header of the first DL transmission.

[0296] Embodiment 30: The method of embodiment 25, wherein the step of engaging in cooperative MU transmission includes: transmitting, by the first AP, a first trigger frame to at least one first client station among the one or more first client stations, while the second AP transmits a second trigger frame to at least one second client station among the one or more second client stations; and receiving, at the first AP, a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the second AP in response to the second trigger frame.

[0297] Embodiment 31: The method of embodiment 30, further comprising a step in the first AP of determining a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame, wherein transmitting a first trigger frame includes transmitting a first trigger frame in a first frequency RU, while the second AP transmits a second trigger frame in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU, and receiving a first UL transmission includes receiving a first UL transmission in a first frequency RU, while at least one second client station transmits a second UL transmission in a second RU.

[0298] Embodiment 32: The method of embodiment 30 further comprises: at the first AP, determining a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame; at the first AP, determining one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for cooperative MU transmission in the notification frame; and at the first AP, generating a first trigger frame to instruct one or more first client stations to transmit during a first UL transmission in the first frequency RU via the one or more first spatial streams, wherein receiving the first UL transmission includes receiving the first UL transmission in the first frequency RU via the one or more first spatial streams, while at least one second client station transmits a second UL transmission in the first RU via one or more second spatial streams.

[0299] Embodiment 33: A method described in any of embodiments 30 to 32, further comprising: at the first AP, determining the time length of the first trigger frame based on an indicator of the time length of the first trigger frame in the notification frame; and at the first AP, generating the first trigger frame to have the determined time length.

[0300] Embodiment 34: A method according to any one of embodiments 25 to 33, further comprising: before receiving the notification frame, generating resource request information in the first AP to request an RU for cooperative MU transmission; and transmitting the resource request information to the second AP by the first AP.

[0301] Embodiment 35: The method of any one of embodiments 25 to 34, further comprising, after receiving the notification frame, transmitting a copy of the notification frame by the first AP.

[0302] Embodiment 36: The method of embodiment 35, further comprising, after sending a copy of the notification frame, receiving, at the first AP, a trigger frame from the master AP regarding the cooperative MU transmission, wherein participating in the cooperative MU transmission is in response to the trigger frame.

[0303] Embodiment 37: A first access point (AP) associated with one or more first client stations, the first AP comprising a wireless network interface device including one or more integrated circuit (IC) devices, the one or more IC devices configured to: receive an announcement frame from a second AP associated with one or more second client stations, the announcement frame announcing a cooperative multi-user (MU) transmission involving at least the first AP and the second AP, the announcement frame including an indicator of a frequency resource unit (RU) allocated to the first AP for the cooperative MU transmission; and control the wireless network interface device to engage in the cooperative MU transmission using the frequency RU indicated by the announcement frame, while the second AP also engages in the cooperative MU transmission.

[0304] Embodiment 38: The first AP described in embodiment 37, wherein the one or more IC devices are further configured to control the wireless network interface device to engage in cooperative MU transmission by at least controlling the wireless network interface device to transmit a first downlink (DL) transmission to at least one first client station among one or more first client stations, while the second AP transmits a second DL transmission to at least one second client station among one or more second client stations.

[0305] Embodiment 39: The first AP described in embodiment 38, wherein one or more IC devices are further configured to determine a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame, and to control the radio network interface device to transmit a first DL transmission on the first frequency RU, while the second AP transmits a second DL transmission on a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU.

[0306] Embodiment 40: The first AP described in embodiment 38, wherein the one or more IC devices are further configured to determine a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame, determine one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for cooperative MU transmission in the notification frame, and control the wireless network interface device to transmit a first DL transmission in the first frequency RU using the one or more first spatial streams, while the second AP transmits a second DL transmission in the first frequency RU using one or more second spatial streams.

[0307] Embodiment 41: The first AP described in any of embodiments 38 to 40, wherein the one or more IC devices are further configured to: determine a time length of a signal field based on an indicator of a signal field time length of the cooperative MU transmission in the notification frame, wherein the signal field is to be included in a physical layer (PHY) header in the first DL transmission; and generate the first DL transmission to include a signal field having the time length in the PHY header of the first DL transmission.

[0308] Embodiment 42: The first AP described in embodiment 37, wherein the one or more IC devices are further configured to control the wireless network interface device to engage in cooperative MU transmission by at least: controlling the wireless network interface device to transmit a first trigger frame to at least one first client station among the one or more first client stations, while the second AP transmits a second trigger frame to at least one second client station among the one or more second client stations; and receiving a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the second AP in response to the second trigger frame.

[0309] Embodiment 43: The first AP described in embodiment 42, wherein the one or more IC devices are further configured to determine a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame, control the radio network interface device to transmit a first trigger frame in the first frequency RU, while the second AP transmits a second trigger frame in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU, and receive a first UL transmission in the first frequency RU, while at least one second client station transmits a second UL transmission in the second RU.

[0310] Embodiment 44: The first AP described in embodiment 42, wherein the one or more IC devices are further configured to determine a first frequency RU based on an indicator of an RU assigned to the first AP in the notification frame, determine one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for cooperative MU transmission in the notification frame, generate a first trigger frame to instruct one or more first client stations to transmit during a first UL transmission in the first frequency RU via the one or more first spatial streams, and receive the first UL transmission in the first frequency RU via the one or more first spatial streams, while at least one second client station transmits a second UL transmission in the first RU via one or more second spatial streams.

[0311] Embodiment 45: A first AP described in any of embodiments 42 to 44, wherein one or more IC devices are further configured to determine the time length of the first trigger frame based on an indicator of the time length of the first trigger frame in the notification frame, and to generate the first trigger frame to have the determined time length.

[0312] Embodiment 46: A first AP described in any of embodiments 37 to 45, wherein the one or more IC devices are further configured to, before receiving the notification frame, generate resource request information to request an RU for cooperative MU transmission, and control the wireless network interface device to transmit the resource request information to the second AP.

[0313] Embodiment 47: The first AP described in any of embodiments 37 to 46, wherein the one or more IC devices are further configured to control the wireless network interface device to transmit a copy of the notification frame after receiving the notification frame.

[0314] Embodiment 48: The first AP described in embodiment 47, wherein the one or more IC devices are further configured to, after transmitting a copy of the notification frame, receive a trigger frame from the master AP regarding the cooperative MU transmission, and, in response to receiving the trigger frame, control the wireless network interface device to participate in the cooperative MU transmission.

[0315] Embodiment 49: A method for cooperative transmission in a multiple wireless communication network, the method comprising: determining, at a first access point (AP), that the first AP is to be included in a master AP for cooperative multi-user (MU) transmission involving multiple APs, including the first AP and one or more second APs; receiving resource request information from one or more second APs regarding access to a wireless communication medium by the one or more second APs for the cooperative MU transmission; allocating, at the first AP, frequency resource units (RUs) for the cooperative MU transmission to the first AP and one or more second APs based on the resource request information received from the one or more second APs; generating, at the first AP, a notification frame regarding the cooperative MU transmission, wherein the notification frame includes allocation information regarding the RUs allocated to the one or more second APs for the cooperative MU transmission; transmitting, by the first AP, a notification frame to provide, to the one or more second APs, allocation information regarding the RUs allocated to the one or more second APs; and participating in the cooperative MU transmission by the first AP, while the one or more second APs participate in the cooperative MU transmission.

[0316] Embodiment 50: The method described in embodiment 49, wherein the step of receiving resource request information from one of the second APs includes a step of receiving a packet from one of the second APs by the first AP, the packet being transmitted in response to the second AP competing for and acquiring the wireless communication medium to transmit the packet, and the packet including resource request information from the one second AP.

[0317] Embodiment 51: The method of embodiment 49, further comprising: generating a trigger frame at a first AP configured to prompt at least one second AP among one or more second APs to transmit resource request information; and transmitting the trigger frame by the first AP to prompt the at least one second AP to transmit resource request information, wherein receiving the resource request information includes receiving the resource request information from the at least one second AP in response to transmitting the trigger frame.

[0318] Embodiment 52: The method described in embodiment 51, wherein generating a trigger frame includes including an identifier of one second AP in the trigger frame, and receiving resource request information includes receiving resource request information from one second AP.

[0319] Embodiment 53: The method of embodiment 52, wherein the identifier of the one second AP in the trigger frame includes a medium access control (MAC) address of the one second AP.

[0320] Embodiment 54: The method described in item 52, wherein the identifier of the one second AP in the trigger frame includes a first set of bits from a basic service set (BSS) color identifier of the one second AP and a second set of bits generated from a medium access control (MAC) address of the one second AP.

[0321] Embodiment 55: The method of embodiment 54, wherein the second set of bits generated from the MAC address of the one second AP includes a set of bits generated by applying a hash function to the MAC address of the one second AP.

[0322]

[0081] Embodiment 56: The method of any one of embodiments 49 to 55, wherein receiving resource request information includes receiving, from one second AP, an indicator of a frequency bandwidth requested by the one second AP for cooperative MU transmission.

[0323]

[0081] Embodiment 57: The method of any of embodiments 49 to 56, wherein receiving resource request information includes receiving from one second AP an indicator of a time length of a packet to be transmitted during a cooperative MU transmission.

[0324]

[0081] Embodiment 58: The method of any of embodiments 49 to 57, wherein receiving resource request information includes receiving from one second AP an indicator of a time length of a signal field in a physical layer (PHY) header of a packet to be transmitted during a cooperative MU transmission.

[0325] Embodiment 59: A communications device comprising a wireless network interface device implemented on one or more ICs, the one or more ICs configured to implement any of the methods described in embodiments 49 to 58.

[0326] Embodiment 60: A method for wireless communication by a client station associated with a first access point (AP), comprising: receiving at the client station an announcement frame transmitted by a second AP to which the client station is not associated, the announcement frame announcing a cooperative multi-user (MU) transmission involving the second AP and one or more other APs, the announcement frame including one or more respective network identifiers of the one or more other APs, and the announcement frame further including a time length field indicating a time length corresponding to the cooperative MU transmission; and, in response to receiving the announcement frame, determining whether the network identifier of the client station is a network identifier of the client station based on a value of the time length field in the announcement frame. A method comprising: setting an allocation vector (NAV) counter; determining, at the client station, that an announcement frame includes a network identifier of a first AP; determining, at the client station, that the client station transmits on a communication channel to the first AP as part of a cooperative MU transmission; determining, at the client station, that the communication channel is idle in response to the announcement frame including the network identifier of the first AP, including ignoring the NAV counter in response to determining that the NAV counter has been set; and transmitting by the client station as part of the cooperative MU transmission in response to determining that the communication channel is idle.

[0327] Embodiment 61: The method of embodiment 60, wherein the cooperative MU transmission includes respective downlink transmissions by the first AP and the second AP, and transmitting by the client station as part of the cooperative MU transmission includes transmitting to the first AP after the respective downlink transmissions by the first AP and the second AP.

[0328] Embodiment 62: A method according to either embodiment 60 or 61, further comprising: maintaining at the client station a first NAV counter for transmissions in a basic service set (BSS) managed by the first AP; and maintaining at the client station a second NAV counter for transmissions not within the BSS managed by the first AP, wherein setting the NAV counter of the notifying client station based on the value of the time length field in the frame includes setting the first NAV counter in response to determining that the notification frame transmitted by the second AP includes the network identifier of the first AP.

[0329] Embodiment 63: A communications device comprising a wireless network interface device implemented on one or more ICs, the one or more ICs configured to implement any of the methods described in embodiments 60 to 62.

[0330] At least some of the various blocks, operations, and techniques described above may be implemented using hardware, a processor executing firmware instructions, a processor executing software instructions, or any combination thereof. When implemented using a processor executing software or firmware instructions, the software or firmware instructions may be stored in any suitable computer-readable memory, such as random access memory (RAM), read-only memory (ROM), flash memory, etc. The software or firmware instructions may include machine-readable instructions that, when executed by one or more processors, cause the one or more processors to perform various operations.

[0331] When implemented in hardware, the hardware may comprise one or more of discrete components, an integrated circuit, an application specific integrated circuit (ASIC), a programmable logic device (PLD), and so on.

[0332] While the present invention has been described with reference to particular examples, these examples are intended to be illustrative rather than limiting of the invention, and modifications, additions and / or deletions may be made to the disclosed embodiments without departing from the scope of the invention. [Other possible items] (Item 1) 1. A method for wireless communication by a first access point (AP) associated with one or more first client stations, the method comprising: generating, at a first AP, an announcement frame announcing a cooperative multi-user (MU) transmission involving a plurality of APs, including the first AP and one or more second APs, each of the second APs being associated with a respective one or more second client stations, the announcement frame being generated to indicate a respective one or more frequency resource units (RUs) allocated to the one or more second APs for the cooperative MU transmission; transmitting the notification frame by the first AP to the one or more second APs to initiate the cooperative MU transmission; participating in the cooperative MU transmission by the first AP, while the one or more second APs also participate in the cooperative MU transmission; A method for providing (Item 2) Item 1, wherein engaging in the cooperative MU transmission includes transmitting, by the first AP, a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while a second AP transmits a second DL transmission to at least one second client station among the one or more second client stations. (Item 3) generating the notification frame includes generating a notification frame to indicate that the one second AP is assigned to a first frequency RU; Item 3. The method of item 2, wherein transmitting the first DL transmission includes transmitting the first DL transmission in a second frequency RU, while the one second AP transmits the second DL transmission in the first RU, the second RU not overlapping in frequency with the first frequency RU. (Item 4) generating the notification frame includes generating the notification frame to indicate that the one second AP is assigned a first frequency RU and one or more first spatial streams; Item 3. The method of item 2, wherein the step of transmitting the first DL transmission includes a step of transmitting the first DL transmission on the first frequency RU using one or more second spatial streams, while the one second AP transmits the second DL transmission on the first frequency RU using one or more first spatial streams. (Item 5) The step of generating the notification frame comprises: generating the notification frame to include an indication of a time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission; generating, in the first AP, the first DL transmission to include a signal field in a PHY header of the first DL transmission, wherein the signal field in the PHY header of the first DL transmission has the duration of the signal field in the PHY header of the second DL transmission; The method according to item 2, comprising: (Item 6) The steps involved in the above cooperative MU transmission are: transmitting, by the first AP, a first trigger frame to at least one first client station among the one or more first client stations, while a second AP transmits a second trigger frame to at least one second client station among the one or more second client stations; receiving, at the first AP, a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the one second AP in response to the second trigger frame; Item 1. The method according to item 1, comprising: (Item 7) generating the notification frame includes generating the notification frame to indicate that the one second AP is assigned a first frequency RU; 7. The method of claim 6, wherein receiving the first UL transmission includes receiving the first UL transmission in a second frequency RU, while the at least one second client station transmits the second UL transmission in the first RU, the second RU not overlapping in frequency with the first frequency RU. (Item 8) generating the notification frame includes generating the notification frame to indicate that the one second AP is assigned a first frequency RU and one or more first spatial streams; 7. The method of claim 6, wherein receiving the first UL transmission includes receiving the first UL transmission in the first frequency RU via one or more second spatial streams, while the at least one second client station transmits the second UL transmission in the first RU via the one or more first spatial streams. (Item 9) generating the notification frame includes generating the notification frame to include an indication of a time length of the second trigger frame; The step of participating in the cooperative MU transmission includes generating the first trigger frame at the first AP to have the duration of the second trigger frame. The method according to item 6. (Item 10) receiving, at the first AP, resource request information from the one or more second APs; allocating, in the first AP, the one or more frequency RUs to the one or more second APs for the cooperative MU transmission based on the resource request information from the one or more second APs; Item 1, further comprising: (Item 11) receiving, at the first AP, one or more respective copies of the notification frame from the one or more second APs after transmitting the notification frame; transmitting, by the first AP, a further copy of the notification frame upon receipt of the one or more respective copies of the notification frame; Item 1, further comprising: (Item 12) Item 12. The method of item 11, further comprising, after receiving the one or more respective copies of the notification frame, transmitting a trigger frame by the first AP to the one or more second APs to initiate the cooperative MU transmission. (Item 13) a first access point (AP) associated with one or more first client stations, the first AP comprising a wireless network interface device, the wireless network interface device comprising: generating an announcement frame announcing a cooperative multi-user (MU) transmission involving a plurality of APs, including the first AP and one or more second APs, each of the second APs associated with a respective one or more second client stations, the announcement frame being generated to indicate a respective one or more frequency resource units (RUs) allocated to the one or more second APs for the cooperative MU transmission; controlling the wireless network interface device to transmit the notification frame to the one or more second APs to initiate the cooperative MU transmission; and controlling the wireless network interface device to participate in the cooperative MU transmission, while the one or more second APs also participate in the cooperative MU transmission; a first AP including a wireless network interface device including one or more integrated circuit (IC) devices configured to perform the following: (Item 14) The one or more IC devices include at least: and controlling a wireless network interface device to transmit a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while a second AP transmits a second DL transmission to at least one second client station among the one or more second client stations, thereby Item 14. The first AP of item 13, configured to control the wireless network interface device to participate in the cooperative MU transmission. (Item 15) The one or more IC devices generate the notification frame to indicate that the one second AP is assigned a first frequency RU; and controlling the wireless network interface device to transmit the first DL transmission in a second frequency RU, while the one second AP transmits the second DL transmission in the first RU, the second RU not overlapping in frequency with the first frequency RU; Item 15. The first AP according to item 14, configured to perform the following: (Item 16) The one or more IC devices generating the notification frame to indicate that the one second AP is assigned a first frequency RU and one or more first spatial streams; and controlling a wireless network interface device to transmit the first DL transmission on the first frequency RU using one or more second spatial streams, while the one second AP transmits the second DL transmission on the first frequency RU using the one or more first spatial streams; Item 15. The first AP according to item 14, configured to perform the following: (Item 17) The one or more IC devices generating the notification frame to include an indication of a time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission; and generating the first DL transmission to include a signal field in a PHY header of the first DL transmission, the signal field in the PHY header of the first DL transmission having the duration of the signal field in the PHY header of the second DL transmission; Item 15. The first AP according to item 14, configured to perform the following: (Item 18) The one or more IC devices include at least: controlling the wireless network interface device to transmit a first trigger frame to at least one first client station among the one or more first client stations, while a second AP transmits a second trigger frame to at least one second client station among the one or more second client stations; and receiving a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the one second AP in response to the second trigger frame; Item 14. The first AP of item 13, configured to control the wireless network interface device to participate in the cooperative MU transmission by performing the following. (Item 19) The one or more IC devices generate the notification frame to indicate that the one second AP is assigned a first frequency RU; and receiving the first UL transmission on a second frequency RU, while the at least one second client station transmits the second UL transmission on the first RU, the second RU not overlapping in frequency with the first frequency RU; Item 19. The first AP according to item 18, configured to: (Item 20) The one or more IC devices generate the notification frame to indicate that the one second AP is assigned a first frequency RU and one or more first spatial streams; and receiving the first UL transmission in the first frequency RU via one or more second spatial streams, while the at least one second client station transmits the second UL transmission in the first RU via the one or more first spatial streams. Item 19. The first AP according to item 18, configured to: (Item 21) the one or more IC devices generating the notification frame to include an indication of a time length of the second trigger frame; and generating the first trigger frame to have the time length of the second trigger frame; Item 19. The first AP according to item 18, configured to: (Item 22) The one or more IC devices further include: receiving resource request information from the one or more second APs; and Allocating the one or more frequency RUs to the one or more second APs for the cooperative MU transmission based on the resource request information from the one or more second APs. Item 14. The first AP according to item 13, configured to perform the following: (Item 23) The one or more IC devices further include: receiving one or more respective copies of the notification frame from the one or more second APs after transmitting the notification frame; and controlling the wireless network interface device to transmit a further copy of the notification frame concurrently with receiving the one or more respective copies of the notification frame from the one or more second APs. Item 14. The first AP according to item 13, configured to perform the following: (Item 24) The one or more IC devices further include: The first AP described in Item 23, configured to control the wireless network interface device to send a trigger frame to the one or more second APs to initiate the cooperative MU transmission after receiving the one or more respective copies of the notification frame. (Item 25) 1. A method for wireless communication by a first access point (AP) associated with one or more first client stations, the method comprising: receiving, at the first AP, an announcement frame from a second AP associated with the one or more second client stations, the announcement frame announcing a cooperative multi-user (MU) transmission involving at least the first AP and the second AP, the announcement frame including an indicator of a frequency resource unit (RU) allocated to the first AP for the cooperative MU transmission; Engaging in the cooperative MU transmission by the first AP using the frequency RU indicated by the announcement frame, while the second AP also engages in the cooperative MU transmission; A method for providing (Item 26) Item 26. The method of item 25, wherein the step of participating in the cooperative MU transmission includes a step of transmitting, by the first AP, a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while the second AP transmits a second DL transmission to at least one second client station among the one or more second client stations. (Item 27) The method further includes determining, in the first AP, a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; 27. The method of claim 26, wherein the step of transmitting the first DL transmission includes the step of transmitting the first DL transmission on the first frequency RU, while the second AP transmits the second DL transmission on a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU. (Item 28) determining, in the first AP, a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; determining, at the first AP, one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for the cooperative MU transmission in the notification frame; Further provided with transmitting the first DL transmission includes transmitting the first DL transmission on the first frequency RU using one or more first spatial streams, while the second AP transmits the second DL transmission on the first frequency RU using the one or more second spatial streams. Item 27. The method according to item 26. (Item 29) determining, in the first AP, a signal field duration based on a signal field duration indicator for the cooperative MU transmission in the notification frame, the signal field to be included in a physical layer (PHY) header of the first DL transmission; generating the first DL transmission in the first AP so that the signal field having the time length is included in the PHY header of the first DL transmission; 27. The method of claim 26, further comprising: (Item 30) The steps involved in the above cooperative MU transmission are: transmitting, by the first AP, a first trigger frame to at least one first client station among the one or more first client stations, while transmitting, by the second AP, a second trigger frame to at least one second client station among the one or more second client stations; receiving, at the first AP, a first uplink (UL) transmission from the at least one first client station, while the at least one second client station transmits a second UL transmission to the second AP in response to the second trigger frame; Item 26. The method according to Item 25, comprising: (Item 31) The method further comprises determining, in the first AP, a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; transmitting the first trigger frame includes transmitting the first trigger frame on the first frequency RU, while the second AP transmits the second trigger frame on a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; receiving the first UL transmission includes receiving the first UL transmission in the first frequency RU, while the at least one second client station transmits the second UL transmission in the second RU; The method according to item 30. (Item 32) determining, in the first AP, a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; determining, at the first AP, one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for the cooperative MU transmission in the notification frame; generating, at the first AP, the first trigger frame to instruct the one or more first client stations to transmit during the first UL transmission in the first frequency RU via the one or more first spatial streams; and receiving the first UL transmission includes receiving the first UL transmission in the first frequency RU via one or more first spatial streams, while the at least one second client station transmits the second UL transmission in the first RU via one or more second spatial streams. (Item 33) determining, in the first AP, the duration of the first trigger frame based on an indicator of the duration of the first trigger frame in the notification frame; generating the first trigger frame at the first AP so as to have the determined time length; 31. The method of claim 30, further comprising: (Item 34) Before receiving the notification frame, generating resource request information in the first AP to request RUs for the cooperative MU transmission; transmitting the resource request information to the second AP by the first AP; 26. The method of claim 25, further comprising: (Item 35) 26. The method of claim 25, further comprising transmitting a copy of the notification frame by the first AP after receiving the notification frame. (Item 36) receiving, at the first AP, a trigger frame from the master AP regarding the cooperative MU transmission after transmitting the copy of the notification frame; Item 36. The method of item 35, wherein participating in the cooperative MU transmission is in response to the trigger frame. (Item 37) a first access point (AP) associated with one or more first client stations, the first AP comprising a wireless network interface device including one or more integrated circuit (IC) devices, the one or more IC devices: receiving an announcement frame from a second AP associated with one or more second client stations, the announcement frame announcing a cooperative multi-user (MU) transmission involving at least the first AP and the second AP, the announcement frame including an indicator of a frequency resource unit (RU) allocated to the first AP for the cooperative MU transmission; and controlling the wireless network interface device to participate in the cooperative MU transmission using the frequency RU indicated by the announcement frame, while the second AP also participates in the cooperative MU transmission; The first AP is configured to perform the above. (Item 38) The first AP described in Item 37, wherein the one or more IC devices are further configured to control the wireless network interface device to participate in the cooperative MU transmission by at least controlling the wireless network interface device to transmit a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while the second AP transmits a second DL transmission to at least one second client station among the one or more second client stations. (Item 39) The one or more IC devices further include: determining a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; and controlling the wireless network interface device to transmit the first DL transmission on the first frequency RU, while the second AP transmits the second DL transmission on a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; Item 39. The first AP according to Item 38, configured to: (Item 40) The one or more IC devices further include: determining a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; determining one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for the cooperative MU transmission in the notification frame; and controlling the wireless network interface device to transmit the first DL transmission on the first frequency RU using one or more first spatial streams, while the second AP transmits the second DL transmission on the first frequency RU using the one or more second spatial streams; Item 39. The first AP according to Item 38, configured to: (Item 41) The one or more IC devices further include: determining a signal field duration based on a signal field duration indicator of the cooperative MU transmission in the notification frame, the signal field being included in a physical layer (PHY) header of the first DL transmission; and generating the first DL transmission to include, in the PHY header of the first DL transmission, the signal field having the time length; Item 39. The first AP according to Item 38, configured to: (Item 42) The one or more IC devices further include at least: controlling the wireless network interface device to transmit a first trigger frame to at least one first client station among the one or more first client stations, while the second AP transmits a second trigger frame to at least one second client station among the one or more second client stations; and receiving a first uplink (UL) transmission from the at least one first client station, while the at least one second client station sends a second UL transmission to the second AP in response to the second trigger frame; Item 38. The first AP of item 37, configured to control the wireless network interface device to participate in the cooperative MU transmission by performing the following. (Item 43) The one or more IC devices further include: determining a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; controlling the wireless network interface device to transmit the first trigger frame on the first frequency RU, while the second AP transmits the second trigger frame on a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; and receiving the first UL transmission in the first frequency RU, while the at least one second client station transmits the second UL transmission in the second RU; The first AP according to item 42, configured to perform the following: (Item 44) The one or more IC devices further include: determining a first frequency RU based on the indicator of the RU assigned to the first AP in the notification frame; determining one or more first spatial streams based on an indicator of one or more spatial streams assigned to the first AP for the cooperative MU transmission in the notification frame; generating the first trigger frame to instruct the one or more first client stations to transmit during the first UL transmission in the first frequency RU via the one or more first spatial streams; and receiving the first UL transmission in the first frequency RU via one or more first spatial streams, while the at least one second client station transmits the second UL transmission in the first RU via the one or more second spatial streams; The first AP according to item 42, configured to perform the following: (Item 45) The one or more IC devices further include: determining the duration of the first trigger frame based on an indicator of the duration of the first trigger frame in the notification frame; and generating the first trigger frame to have the determined time length; The first AP according to item 42, configured to perform the following: (Item 46) The one or more IC devices further generate resource request information to request RUs for the cooperative MU transmission before receiving the notification frame; and controlling the wireless network interface device to send the resource request information to the second AP; Item 38. The first AP according to Item 37, configured to perform the following: (Item 47) The one or more IC devices further include: Item 38. The first AP according to item 37, configured to, after receiving the notification frame, control the wireless network interface device to transmit a copy of the notification frame. (Item 48) The one or more IC devices further include: receiving a trigger frame from the master AP regarding the cooperative MU transmission after transmitting the copy of the notification frame; and In response to receiving the trigger frame, controlling the wireless network interface device to participate in the cooperative MU transmission. Item 48. The first AP according to Item 47, configured to:

Claims

1. 1. A method for wireless communication by a first access point (AP) associated with one or more first client stations, the method comprising: generating, at a first AP, an announcement frame announcing a cooperative multi-user (MU) transmission for a plurality of APs, including the first AP and one or more second APs, each of the second APs being associated with a respective one or more second client stations, the announcement frame being generated to indicate one or more respective sets of communication parameters to be used by the one or more second APs to communicate with the respective one or more second client stations during the cooperative MU transmission; transmitting the notification frame by the first AP to the one or more second APs to notify the cooperative MU transmission; After transmitting the notification frame, transmitting a trigger frame by the first AP to the one or more second APs to initiate the cooperative MU transmission; participating in the cooperative MU transmission by the first AP; A method for providing

2. The step of engaging in the cooperative MU transmission includes transmitting a first downlink (DL) transmission by the first AP to at least one first client station among the one or more first client stations, while a second AP transmits a second DL transmission to at least one second client station among the one or more second client stations. The method of claim 1 , comprising:

3. The one or more respective sets of communication parameters used by the one or more second APs include an indication of a first frequency resource unit (RU) assigned to the one second AP; transmitting the first DL transmission includes transmitting the first DL transmission in a second frequency RU while the one second AP transmits the second DL transmission in the first frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU. The method of claim 2.

4. The one or more respective sets of communication parameters used by the one or more second APs include an indication of one or more first spatial streams assigned to the one second AP; transmitting the first DL transmission includes transmitting the first DL transmission using one or more second spatial streams while the one second AP transmits the second DL transmission using the one or more first spatial streams; The method according to claim 2 or 3.

5. The one or more respective sets of communication parameters used by the one or more second APs include an indication of a time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission; The method comprises: generating the first DL transmission at the first AP to include a signal field in a PHY header of the first DL transmission, the signal field in the PHY header of the first DL transmission having the duration of the signal field in the PHY header of the second DL transmission; The method of claim 2 , further comprising:

6. the trigger frame is a first trigger frame; The steps of participating in the cooperative MU transmission include: transmitting, by the first AP, a second trigger frame to at least one first client station among the one or more first client stations, while a second AP transmits a third trigger frame to at least one second client station among the one or more second client stations; receiving at the first AP a first uplink (UL) transmission from the at least one first client station in response to the second trigger frame, while the at least one second client station sends a second UL transmission to the one second AP in response to the third trigger frame; The method of claim 1 , comprising:

7. The method of claim 6, wherein the one or more respective sets of communication parameters used by the one or more second APs include an indication of a first frequency resource unit (RU) allocated to the one or more second APs; receiving the first UL transmission includes receiving the first UL transmission on a second frequency RU while the at least one second client station transmits the second UL transmission on the first frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU. The method of claim 6.

8. The one or more respective sets of communication parameters used by the one or more second APs include an indication of one or more first spatial streams assigned to the one second AP; receiving the first UL transmission includes receiving the first UL transmission via one or more second spatial streams while the at least one second client station transmits the second UL transmission via the one or more first spatial streams.

8. The method according to claim 6 or 7.

9. The one or more respective sets of communication parameters used by the one or more second APs include an indication of a time length of the third trigger frame; and generating the second trigger frame at the first AP to have the duration of the third trigger frame.

9. The method according to any one of claims 6 to 8.

10. receiving, at the first AP, wireless medium resource request information from the one or more second APs; allocating, in the first AP, one or more wireless medium resources to the one or more second APs for the cooperative MU transmission based on the wireless medium resource request information from the one or more second APs; Further provided with the one or more respective sets of communication parameters used by the one or more second APs include an indication of the one or more wireless medium resources allocated to the one or more second APs for the cooperative MU transmission; 10. The method according to any one of claims 1 to 9.

11. receiving, at the first AP, one or more respective copies of the notification frame from the one or more second APs after transmitting the notification frame; transmitting, by the first AP, a further copy of the notification frame concurrently with receiving the one or more respective copies of the notification frame; The method of claim 1 , further comprising:

12. and transmitting, by the first AP, a trigger frame to the one or more second APs to initiate the cooperative MU transmission after receiving the one or more respective copies of the notification frame. The method of claim 11 further comprising:

13. a first access point (AP) associated with one or more first client stations, the first AP being a wireless network interface device; generating an announcement frame announcing a cooperative multi-user (MU) transmission for a plurality of APs, including the first AP and one or more second APs, each of the second APs associated with a respective one or more second client stations, wherein the announcement frame is generated to indicate a set of one or more respective communication parameters to be used by the one or more second APs to communicate with the respective one or more second client stations during the cooperative MU transmission; controlling the wireless network interface device to transmit the notification frame to the one or more second APs to notify the cooperative MU transmission; controlling the wireless network interface device to send a trigger frame to the one or more second APs to initiate the cooperative MU transmission after sending the notification frame; and controlling the wireless network interface device to participate in the cooperative MU transmission; EP1333733A1 - Wireless network interface device including one or more integrated circuit (IC) devices configured to The first AP comprises:

14. the one or more IC devices are configured to control the wireless network interface devices to participate in the cooperative MU transmission by controlling the wireless network interface devices to transmit a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while at least one second AP transmits a second DL transmission to at least one second client station among the one or more second client stations; The first AP according to claim 13.

15. The method of claim 1, wherein the one or more respective sets of communication parameters used by the one or more second APs include an indication that the one second AP is assigned a first frequency resource unit (RU); the one or more IC devices are configured to control the wireless network interface device to transmit the first DL transmission in a second frequency RU while the one second AP transmits the second DL transmission in the first frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; The first AP according to claim 14.

16. The one or more respective sets of communication parameters used by the one or more second APs include an indication that one or more first spatial streams are assigned to the one second AP; the one or more IC devices are configured to control the wireless network interface device to transmit the first DL transmission using one or more second spatial streams while the one second AP transmits the second DL transmission using the one or more first spatial streams; The first AP according to claim 14 or 15.

17. The one or more respective sets of communication parameters used by the one or more second APs include an indication of a time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission; the one or more IC devices are configured to generate the first DL transmission to include a signal field in a PHY header of the first DL transmission, the signal field in the PHY header of the first DL transmission having the same duration as the signal field in the PHY header of the second DL transmission; The first AP according to any one of claims 14 to 16.

18. the trigger frame is a first trigger frame; The one or more IC devices include at least controlling the wireless network interface device to transmit a second trigger frame to at least one first client station among the one or more first client stations while a second AP transmits a third trigger frame to at least one second client station among the one or more second client stations; and receiving a first uplink (UL) transmission from the at least one first client station in response to the second trigger frame, while the at least one second client station sends a second UL transmission to the one second AP in response to the third trigger frame; The first AP of claim 13 , configured to control the wireless network interface device to participate in the cooperative MU transmission by:

19. The method of claim 19, wherein the one or more respective sets of communication parameters used by the one or more second APs include an indication that the one second AP is assigned a first frequency resource unit (RU); the one or more IC devices are configured to receive the first UL transmission on a second frequency RU while the at least one second client station transmits the second UL transmission on the first frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; The first AP according to claim 18.

20. The one or more respective sets of communication parameters used by the one or more second APs include an indication that one or more first spatial streams are assigned to the one second AP; the one or more IC devices are configured to receive the first UL transmission via one or more second spatial streams while the at least one second client station transmits the second UL transmission via the one or more first spatial streams.

20. The first AP according to claim 18 or 19.

21. The one or more respective sets of communication parameters used by the one or more second APs include an indication of a time length of the third trigger frame; the one or more IC devices are configured to generate the second trigger frame to have the time length of the third trigger frame. A first AP according to any one of claims 18 to 20.

22. The one or more IC devices further include: receiving wireless medium resource request information from the one or more second APs; and allocate the one or more wireless medium resources to the one or more second APs for the cooperative MU transmission based on the wireless medium resource request information from the one or more second APs; It is configured as the one or more respective sets of communication parameters used by the one or more second APs include an indication of the one or more wireless medium resources allocated to the one or more second APs for the cooperative MU transmission; The first AP according to any one of claims 13 to 21.

23. The one or more IC devices further include: After transmitting the notification frame, receiving one or more respective copies of the notification frame from the one or more second APs; and controlling the wireless network interface device to transmit a further copy of the notification frame concurrently with receiving one or more respective copies of the notification frame from the one or more second APs; The first AP according to any one of claims 13 to 22, configured to:

24. the one or more IC devices are further configured to, after receiving the one or more respective copies of the notification frame, control the wireless network interface device to send a trigger frame to the one or more second APs to initiate the cooperative MU transmission. The first AP according to claim 23.

25. the wireless network interface device, one or more transceivers at least partially implemented in said one or more IC devices The first AP according to any one of claims 13 to 24, comprising:

26. one or more antennas coupled to the one or more transceivers The first AP of claim 25 further comprising:

27. 1. A method for wireless communication by a first access point (AP) associated with one or more first client stations, the method comprising: receiving, at the first AP, an announcement frame from a second AP, the announcement frame announcing a cooperative multi-user (MU) transmission for a plurality of APs including the first AP and the second AP, the second AP being associated with one or more second client stations, the announcement frame being generated to indicate a set of communication parameters to be used by the first AP to communicate with the one or more first client stations during the cooperative MU transmission; receiving, at the first AP after receiving the notification frame, a trigger frame from the second AP, the trigger frame configured to initiate the cooperative MU transmission; engaging in the collaborative MU transmission by the first AP, wherein the engaging in the collaborative MU transmission by the first AP includes using the set of communication parameters indicated by the announcement frame; A method for providing

28. 28. The method of claim 27, wherein the engaging in the cooperative MU transmission includes transmitting, by the first AP, a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while the second AP transmits a second DL transmission to at least one second client station among the one or more second client stations.

29. The notification frame indicates that a first frequency resource unit (RU) is allocated to the first AP; transmitting the first DL transmission includes transmitting the first DL transmission in the first frequency RU while the second AP transmits the second DL transmission in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU.

29. The method of claim 28.

30. the notification frame indicates that one or more first spatial streams are allocated to the first AP; transmitting the first DL transmission includes transmitting the first DL transmission using the one or more first spatial streams while the second AP transmits the second DL transmission using one or more second spatial streams.

30. The method of claim 28 or 29.

31. the notification frame includes an indication of a time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission; The method comprises: generating the first DL transmission at the first AP to include a signal field in a PHY header of the first DL transmission, the signal field in the PHY header of the first DL transmission having the duration of the signal field in the PHY header of the second DL transmission; 31. The method of any one of claims 28 to 30, further comprising:

32. the trigger frame is a first trigger frame; The steps of participating in the cooperative MU transmission include: transmitting, by the first AP, a second trigger frame to at least one first client station among the one or more first client stations, while the second AP transmits a third trigger frame to at least one second client station among the one or more second client stations; receiving at the first AP a first uplink (UL) transmission from the at least one first client station responsive to the second trigger frame while the at least one second client station sends a second UL transmission to the second AP responsive to the third trigger frame; 28. The method of claim 27, comprising:

33. The notification frame indicates that a first frequency resource unit (RU) is allocated to the first AP for the collaborative MU transmission; receiving the first UL transmission includes receiving the first UL transmission in the first frequency RU while the at least one second client station transmits the second UL transmission in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU.

33. The method of claim 32.

34. The notification frame indicates that one or more first spatial streams are allocated to the first AP for the collaborative MU transmission; receiving the first UL transmission includes receiving the first UL transmission via the one or more first spatial streams while the at least one second client station transmits the second UL transmission via one or more second spatial streams.

34. The method of claim 32 or 33.

35. the notification frame includes an indication of a time length of the third trigger frame; and generating the second trigger frame at the first AP to have the duration of the third trigger frame.

35. The method of any one of claims 32 to 34.

36. transmitting, by the first AP, wireless medium resource request information regarding the collaborative MU transmission to the second AP, the wireless medium resource request information being used by the second AP when allocating one or more wireless medium resources to the plurality of APs for the collaborative MU transmission.

36. The method of any one of claims 27 to 35, further comprising:

37. transmitting a copy of the notification frame by the first AP to the second AP after receiving the notification frame at the same time that the second AP transmits a further copy of the notification frame.

37. The method of any one of claims 27 to 36, further comprising:

38. receiving a trigger frame at the first AP from the second AP after transmitting the copy of the announcement frame, the trigger frame configured to further initiate the cooperative MU transmission.

38. The method of claim 37, further comprising:

39. a first access point (AP) associated with one or more first client stations, the first AP being a wireless network interface device including one or more integrated circuit (IC) devices; receiving an announcement frame from a second AP, the announcement frame announcing a cooperative multi-user (MU) transmission for multiple APs including the first AP and the second AP, the second AP being associated with one or more second client stations, wherein the announcement frame is generated to indicate a set of communication parameters to be used by the first AP to communicate with the one or more first client stations during the cooperative MU transmission; After receiving the notification frame, receive a trigger frame from the second AP, the trigger frame configured to initiate the cooperative MU transmission; and controlling the wireless network interface device to participate in the collaborative MU transmission while the second AP also participates in the collaborative MU transmission, wherein participating in the collaborative MU transmission by the first AP includes using the set of communication parameters indicated by the announcement frame; EP1333733A1 - Wireless network interface device including one or more integrated circuit (IC) devices configured to The first AP comprises:

40. the one or more IC devices are configured to control the wireless network interface device to participate in the cooperative MU transmission by controlling the wireless network interface device to transmit a first downlink (DL) transmission to at least one first client station among the one or more first client stations, while the second AP transmits a second DL transmission to at least one second client station among the one or more second client stations; The first AP according to claim 39.

41. The notification frame indicates that a first frequency resource unit (RU) is allocated to the first AP; the one or more IC devices are configured to control the wireless network interface device to transmit the first DL transmission in the first frequency RU while the second AP transmits the second DL transmission in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; The first AP according to claim 40.

42. the notification frame indicates that one or more first spatial streams are allocated to the first AP; the one or more IC devices are configured to control the wireless network interface device to transmit the first DL transmission using the one or more first spatial streams, while the second AP transmits the second DL transmission using one or more second spatial streams.

42. The first AP according to claim 40 or 41.

43. the notification frame includes an indication of a time length of a signal field to be included in a physical layer (PHY) header of the second DL transmission; the one or more IC devices are further configured to generate the first DL transmission to include a signal field in a PHY header of the first DL transmission, the signal field in the PHY header of the first DL transmission having the time length of the signal field in the PHY header of the second DL transmission.

43. The first AP according to any one of claims 40 to 42.

44. the trigger frame is a first trigger frame; The one or more IC devices include at least controlling the wireless network interface device to transmit a second trigger frame to at least one first client station among the one or more first client stations while the second AP transmits a third trigger frame to at least one second client station among the one or more second client stations; and receiving, at the wireless network interface device, a first uplink (UL) transmission from the at least one first client station responsive to the second trigger frame, while the at least one second client station sends a second UL transmission to the second AP responsive to the third trigger frame; 40. The first AP of claim 39, configured to control the wireless network interface device to participate in the cooperative MU transmission by:

45. The notification frame indicates that a first frequency resource unit (RU) is allocated to the first AP for the collaborative MU transmission; the one or more IC devices are configured to receive, at the wireless network interface device, the first UL transmission in the first frequency RU while the at least one second client station transmits the second UL transmission in a second frequency RU, the second frequency RU not overlapping in frequency with the first frequency RU; The first AP according to claim 44.

46. The notification frame indicates that one or more first spatial streams are allocated to the first AP for the collaborative MU transmission; the one or more IC devices are configured to receive, at the wireless network interface device, the first UL transmission via the one or more first spatial streams, while the at least one second client station transmits the second UL transmission via one or more second spatial streams.

46. ​​The first AP according to claim 44 or 45.

47. the notification frame includes an indication of a time length of the third trigger frame; the one or more IC devices are configured to generate the second trigger frame to have the time length of the third trigger frame.

47. The first AP according to any one of claims 44 to 46.

48. The one or more IC devices further include: and controlling the wireless network interface device to send wireless medium resource request information regarding the collaborative MU transmission to the second AP, wherein the wireless medium resource request information is used by the second AP when allocating one or more wireless medium resources to the plurality of APs for the collaborative MU transmission.

48. A first AP according to any one of claims 39 to 47.

49. the one or more IC devices are further configured to, after receiving the notification frame, control the wireless network interface device to transmit a copy of the notification frame to the second AP at the same time that the second AP transmits a further copy of the notification frame.

49. The first AP according to any one of claims 39 to 48.

50. the one or more IC devices are further configured to receive a trigger frame from the second AP after transmitting the copy of the notification frame, the trigger frame being configured to further initiate the cooperative MU transmission.

50. The first AP of claim 49.

51. the wireless network interface device, one or more transceivers at least partially implemented in said one or more IC devices 51. The first AP according to any one of claims 39 to 50, comprising:

52. one or more antennas coupled to the one or more transceivers The first AP of claim 51 further comprising:

Images