Systems and methods for wireless network with multiple access points

Abstract

A method for wireless communication includes generating, by a first access point, a multiple access points (MAP) trigger signal and transmitting, by the first access point, the MAP trigger signal to initiate a MAP data communication process. The method further includes transmitting first data on a first spatial stream to the station by the first access point, transmitting second data on a second spatial stream to the station by the second access point, the second spatial stream being different from the first spatial stream, and sending a first block acknowledgement request from the first access point to the station.

Description

SYSTEMS AND METHODS FOR WIRELESS NETWORK WITH MULTIPLE ACCESS POINTSBACKGROUND

[0001] At the forefront of the development and implementation of the WiFi standard that allows devices such as computers, smartphones, and tablets to communicate with each other and with wired networks. The WiFi standard is based on the IEEE 802.11 family of networking standards, which specify the physical and data link layer protocols for wireless local area networks (WLANs).

[0002] One of the challenges of WiFi networks is providing sufficient coverage and capacity to support a large number of devices. This can be particularly challenging in large buildings or outdoor areas, where a single wireless access point may not be sufficient to provide adequate coverage. A wireless network with multiple access points (APs) is a solution to provide wireless coverage to a larger area or to support more devices. Coherent joint transmission is a wireless communication technique that allows multiple APs to transmit data to a single device simultaneously in a coordinated manner. It is a type of multi-AP joint transmission that uses coherent signals, which means that the signals from the APs are all in phase with each other. Coherent joint transmission can improve the performance and capacity of a wireless network by allowing more data to be transmitted to a device at once, reducing the amount of time the device has to spend waiting for data. However, the coherent joint transmission needs stringent synchronization between two APs to transmit multiple signals simultaneously over the same frequency band which results in system complexity and vulnerability to phase noise interference.

[0003] Therefore, new and improved systems and methods for multi-AP joint transmissions are desired.BRIEF SUMMARY

[0004] The present disclosure is directed to wireless communication methods and systems. In one embodiment, the present disclosure provides a first access point device that works in conjunction with a second access point device to provide wireless access to a station. Thepresent disclosure provides methods for performing joint transmission for multi -access-points in simplified schemes. There are other embodiments as well.

[0005] A system of one or more computers can be configured to perform particular operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs can be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions. One general aspect of the present disclosure includes a method for wireless communication. The method includes generating a null data packet announcement frame for multiple access points (MAP) communication by a first access point. The method also includes transmitting wirelessly the null data packet announcement frame to trigger a sounding process for the first access point and a second access point. The method also includes transmitting a first null data packet and a second null data packet to a station respectively by the first access point and the second access point simultaneously at a short interframe space (SIFS) time after the sounding process. The method also includes transmitting a first beamforming report poll to the station by the first access point. The method also includes receiving a feedback generated by the station in response to the first beamforming report poll. The feedback contains a first beamforming feedback for the first access point and independently a second beamforming feedback for the second access point. The method also includes generating by the first access point a MAP trigger signal. The method also includes transmitting by the first access point the map trigger signal to initiate a MAP data communication process. The method also includes receiving a channel state information separately from the station and the second access point in response to the MAP trigger signal. The method also includes transmitting a first data block on a first resource unit to the station by the first access point and independently transmitting a second data block on a second resource unit to the station by the second access point. The first resource unit is different from the second resource unit. The method also includes sending a first block acknowledgement request from the first access point to the station. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0006] Implementations may include one or more of the following features. The method may include transmitting channel state information respectively by the second access point and the station in the sounding process. The first access point may be a master access pointand the second access point may be a satellite access point. The method may include measuring a first channel characteristic from the first access point to the station to report in the first beamforming feedback by the station in response to the first null data packet and independently measuring a second channel characteristic from the second access point to the station to report in the second beamforming feedback by the station in response to the second null data packet. The method may include transmitting a second beamforming report poll to the station by the second access point. The MAP trigger signal may include modulation coding scheme, resource allocation information, and spatial stream information. The method may include sending a first block acknowledgement from the station to the first access point. The method may include: sending a second block acknowledgement request from the second access point to the station; and sending a second block acknowledgement from the station to the second access point. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

[0007] Another general aspect of the disclosure includes a method for wireless communication. The method also includes generating a null data packet announcement frame for multiple access points (MAP) communication by a first access point. The method also includes transmitting wirelessly the null data packet announcement frame to trigger a sounding process. The method also includes transmitting a first channel state information and a second channel state information respectively by a second access point and a station in the sounding process. The method also includes transmitting two null data packages simultaneously by the first access point and the second access point at a Short Interframe Space (SIFS) time after receiving the first channel state information and the second channel state information. The method also includes transmitting a first beamforming report poll to the station by the first access point. The method also includes receiving feedback generated by the station in response to the first beamforming report poll. The method also includes generating by the first access point a MAP trigger signal. The method also includes transmitting by the first access point the MAP trigger signal to initiate a MAP data communication process. The method also includes sending a third channel state information by the second channel access point in response to the MAP trigger signal and sending a fourth channel state information by the station in response to the MAP trigger signal. The method also includes transmitting a first data block on a first spatial stream to the station by the first access point. The method also includes transmitting a second data block on a second spatial stream to the station by the second access point, the second spatial stream being different from the first spatial stream. The method also includes sending a first block acknowledgement request from the first access point to the station. Other embodiments ofthis aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0008] Implementations may include one or more of the following features. The method where the first spatial stream and the second spatial stream are associated with different modulation coding schemes (MCS). The method may include forwarding a portion of data from the first access point to the second access point. The first spatial stream and the second spatial stream are associated with a same modulation coding scheme (MCS). The method may include forwarding an entirety of data from the first access point to the second access point. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

[0009] One general aspect includes a method for wireless communication. The method also includes generating a null data packet announcement frame for multiple access points (MAP) communication in a wireless network by a master access point. The method also includes transmitting wirelessly the null data packet announcement frame to trigger a sounding process. The method also includes transmitting a first clear-to-send (CTS) frame and a second CTS frame respectively by a satellite access point and a station in the sounding process. The method also includes transmitting two null data packages simultaneously and respectively by the master access point and the satellite access point at a short interframe space (SIFS) time after the sounding process. The method also includes transmitting a first beamforming report poll frame to the station by the master access point. The method also includes receiving feedback generated by the station in response to the first beamforming report poll frame. The method also includes generating by the master access point a MAP trigger signal. The method also includes transmitting by the master access point the MAP trigger signal to initiate a MAP data communication process. The method also includes sending a third CTS frame by the satellite access point and sending a fourth CTS frame by the station in response to the MAP trigger signal. The method also includes aligning a first symbol transmission of the master access point to a second symbol transmission of the satellite access point. The method also includes transmitting duplicated data block by the master access point and by the satellite access point. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0010] Implementations may include one or more of the following features. The method may include sending a first block acknowledgement request from the master access point tothe station. Transmitting the duplicated data block includes transmitting the same encoded data and sharing the same encoded data between the master access point and the satellite access point. The master access point and the satellite access point are configured orthogonally for transmitting the duplicated data block. The MAP trigger signal includes a length information of data block to be transmitted so that the duplicated data block transmitted by both the master access point and the satellite access point ends at a same symbol boundary. The MAP trigger signal may include a guard interval for transmitting the duplicated data block by both the master access point and the satellite access point. The method may include extending the multiple access point (MAP) communication to additional satellite access points in the wireless network. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

[0011] The present disclosure described hereafter relates to a wireless communication networking system that uses multiple access points to provide enhanced coverage and capacity. In one embodiment, the system of the present disclosure includes multiple access points that are strategically placed throughout the coverage area. The access points are interconnected and coordinate with each other to provide seamless and consistent coverage, allowing devices to roam freely and maintain a stable connection. The multiple access point WiFi system of the present disclosure offers several advantages over existing solutions. It provides greater coverage and capacity, allowing more devices to connect to the network simultaneously. It also offers seamless roaming, allowing devices to move freely within the coverage area without losing their connection. Overall, the multiple access point WiFi system of the present disclosure represents a significant improvement over existing solutions.

[0012] It is to be appreciated that embodiments of the present disclosure provide many advantages over conventional techniques. Among other things, the present disclosure provides a simplified system and method for multi-AP joint transmission that relieves the stringent requirement on synchronization between two Aps in conventional coherent joint transmission. Additionally, the proposed multi-AP joint transmission can be performed in frequency domain with the operating bandwidth of one of two different access points optionally may or may not cover the frequency resources of the resource units sent by another access point. The proposed multi-AP joint transmission can also be performed in spatial domain with the data streams encoded / modulated independently or jointly by different APs being transmitted by different APs. The data streams can optionally be sent in duplicatedfashion in multiple different APs so higher transmit power being achieved compared to single-AP transmission.

[0013] Embodiments of the present disclosure can be implemented in conjunction with existing systems and processes. For example, access point devices implemented multi-AP joint transmission method according to the present disclosure can be used in a wide variety of systems, including WLAN networks on WiFi 6 or WiFi 7 communication protocols, or may be evaluated for futural WiFi 8 protocol. Additionally, various techniques according to the present disclosure can be adopted into existing systems via routers, mesh systems, repeaters, or standalone APs to create a WiFi network and can be configured to use multi-AP joint transmission to improve the performance of the wireless network. There are other benefits as well.

[0014] The present disclosure achieves these benefits and others in the context of known technology. However, a further understanding of the nature and advantages of the present disclosure may be realized by reference to the latter portions of the specification and attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure l is a simplified block diagram illustrating multiple access point wireless communication system according to embodiments of the present disclosure.

[0016] Figure 2 is a simplified block diagram illustrating an access point device 200 according to embodiments of the present disclosure.

[0017] Figure 3 is a timing diagram illustrating an exemplary multiple access point data transmission scheme according to embodiments of the present disclosure.

[0018] Figure 4 is a block diagram illustrating multiple access point data transmission schemes according to embodiments of the present disclosure.

[0019] Figure 5 is a timing diagram illustrating another exemplary multiple access point data transmission scheme according to embodiments of the present disclosure.

[0020] Figure 6 is a timing diagram illustrating yet another exemplary multiple access point data transmission scheme according to embodiments of the present disclosure.

[0021] Figures 7A and 7B are simplified flow diagrams of a multiple access point data transmission method according to embodiments of the present disclosure.

[0022] Figures 8A and 8B are simplified flow diagrams of another multiple access point data transmission method according to embodiments of the present disclosure.

[0023] Figures 9A and 9B are simplified flow diagrams flow diagram of yet another multiple access point data transmission method according to embodiments of the present disclosure.DETAILED DESCRIPTION

[0024] The present disclosure is directed to wireless communication methods and systems. In a specific embodiment, the present disclosure provides a first access point device that works in conjunction with a second access point device to provide wireless access to a station. There are other embodiments as well.

[0025] A wireless local area network (WLAN) such as wireless fidelity (WiFi) is a local area network (LAN) protocol that can be operated on the frequency bands provided by the standard, allowing users to communicate with each other without the need for physical cables. Under IEEE 802.11 standard, WiFi has evolved over the years to include additional features such as data encryption, seamless roaming, and enhanced security protocols. The present disclosure provides how WiFi works with multiple access points and its advantages over existing wired LANs.

[0026] WiFi can be used as a single-mode network or as a multi-mode network. In singlemode networks, only one access point is present which serves all connected devices within range of its signal. In multi-mode networks, however, multiple access points are used in order to increase coverage by overlapping signals from different directions. By using this method, users who are located at different distances from the access points are able to receive strong signals no matter where they are located within range of the network.

[0027] When using WiFi with multiple access points, each device must first authenticate itself with an access point before gaining internet connectivity and communication between devices is done over the same channel or frequency band throughout the entire network. This means that data transmission speed may vary depending on how many users are currently connected to each particular channel or band - if there are too many users on a single band, then performance may suffer due to increased congestion. Additionally, since every device must authenticate itself with every access point within range of its signal in order to maintain uninterrupted connections across multiple channels or bands, devices must be configured appropriately in order for this process to occur successfully and efficiently.

[0028] The main advantage of using WiFi with multiple access points is increased coverage area and signal strength when compared to single-mode networks. By utilizing multiple overlapping signals from different directions, users who are located far away from an access point can still receive reliable signals when compared to those who would only be able to connect through one access point in a single-mode setup. Additionally, by allowing devices authenticated with one access point roam freely throughout other parts of the network without needing manual reauthentication allows for greater ease of use overall when compared to traditional wired LANs which require manual configuration upon moving locations within their physical boundaries. Finally, since data transmission speed can vary based on how many users are currently connected at any given time allows for greater optimization than what could be achieved using a single radio channel as more resources can be allocated towards areas where they are most needed while less congested channels remain available as backups should demand suddenly increase beyond existing capacity limits.

[0029] Overall, WiFi with multiple access points provides numerous advantages over other approaches by providing greater coverage area and signal strength while also reducing administrative overhead associated with manual reauthentication process required when devices move locations within existing physical boundaries of wired networks - this makes larger scale deployments much easier due to reduced complexity associated with such setups when compared against their wired counterparts while still providing similar performance benefits over single-access point configurations in regards to data transmission speeds based on user capacity.

[0030] The following description is presented to enable one of ordinary skill in the art to make and use the present disclosure and to incorporate it in the context of particular applications. Various modifications, as well as a variety of uses in different applications will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to a wide range of embodiments. Thus, the present disclosure is not intended to be limited to the embodiments presented, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0031] In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that the present disclosure may be practiced without necessarily being limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present disclosure.

[0032] The reader’s attention is directed to all papers and documents which are filed concurrently with this specification, and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0033] All the features disclosed in this specification, (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0033] Please note, if used, the labels left, right, front, back, top, bottom, forward, reverse, clockwise and counterclockwise have been used for convenience purposes only and are not intended to imply any particular fixed direction. Instead, they are used to reflect relative locations and / or directions between various portions of an object.

[0034] Figure l is a simplified block diagram illustrating multiple access point wireless communication system 100 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. FIG. 1 shows a wireless communication system 100 with multiple access points including several key components. System 100 includes multiple access point devices such as API (121), AP2 (122) that are configured to transmit and receive wireless signals for connecting each other and between multiple user devices 140 in a wireless local network with coverage over a larger local area and increased capacity. System 100 also includes Ethernet 110, an exemplary network management hardware / software, that is used to configure and manage the multiple APs, 121 and 122, connect various data sources including wired network infrastructure and internet to the local network, monitor the performance of the local network including data transmission and receiving through the one or more of the multiple APs, and troubleshoot any issues that may arise. In some embodiments, the multiple APs 121 and 122 are configured to transmit various null data packages and data blocks to each other or to user devices via joint transmission methods. System 100 further includes a wireless link 130 for connecting the APs to multiple user devices 140. The wireless link 130 typically includes network infrastructure hardware and software used to connect the APs and manage the network, such as routers, switches, and signal converters, and antennas used to transmit and receive wireless signals. User devices 140 are any devices that connect to the network, such as laptops, smartphones, and tablets. One or more such devices can serve as station(s) whichis capable of connecting to the wireless network and communicating with other devices over the wireless link 130 through the multiple access point devices 121 and 122 via joint transmission methods.

[0035] Figure 2 is a simplified block diagram illustrating an access point device 200 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. The access point device 200 is an example of one of the multiple APs 121 and 122 shown in the wireless communication system 100 shown in FIG. 1. As shown in FIG. 2, access point device 200 includes multiple antennas 210, for example, 4 antennas, each providing a wireless channel for transmitting or receiving radio signals in a wireless network. The type and number of antennas can affect the range and performance of the access point. The same antenna may be used for transmitting signal or receiving signal. Thus, access point device 200 may use a T / R switch 220 to handling outgoing or incoming signal in a same channel. The T / R switch 220 can be configured for multi-In Multi-out signal handling. The outgoing or incoming signal is referred to analog signal in radio frequency, usually in a specific frequency band such as 2.4 GHz or 5 GHz for WiFi networks. In some embodiments, the frequency band further includes, but not limited to, 860 / 900 MHz, 3.6 GHz, 4.9 GHz, 5.9 GHz, 6 GHz, 45 GHz and 60 GHz. Access point device 200 may include a radio device 250 for converting the incoming analog signals to digital signals or converting digital signals (coming from a signal processor or data source) to outgoing analog signals. Radio device 250 may include signal modulation function based on certain modulation coding scheme selected by the signal processor. Access point device 200 may include a power amplifier 230 to amplify the outgoing signals before letting them through T / R switch 220 to be transmitted over the wireless network by multiple antennas 210.

[0036] Processor 280 is the "brain" of the access point device 200, responsible for running the device's operating system and performing various tasks. When a user device in the network connected to the access point device 200 sends data, the processor 280 receives the data and prepares it for transmission over the wireless network. This may involve breaking the data down into smaller packets or data blocks on different resource units or spatial streams, adding null data package headers and other information, and encoding the data. Once the data is prepared, processor 290 sends it to radio 250, which converts the data into a wireless signal. The signal will be amplified by power amplifier 230. After the signal is passed through the T / R switch 220, antennas broadcast it over the network. When otherdevices (including other access point devices within a multi-AP system) on the network receive the signal, their radio devices convert the signal back into data and send it to their processors for processing. Processor 290 is also responsible for managing the various tasks involved in receiving data from other devices on the network. When a device on the network sends data to this access point device, processor 290 receives the data, decodes it, and passes it on to the device that requested it.

[0037] Access point device may include a Memory 290 to store the operation system of the access point device 200 and other data. Access point device 200 further includes Ethernet port 240 for connecting wired network via an Ethernet cable to share various data sources or entire internet with the processor 290. Processor 290 may also be responsible for managing the AP's connection to the Internet, handling security measures such as encryption, and performing other tasks as needed. Access point device 200 additionally may include a configuration interface 260 such as web-based interface or command-line interface that allows users to set up and manage the device or restore the device to its factory default settings. Access point device also has firmware stored within for controlling its operation, which can be updated to add new features or fix bugs.

[0038] Figure 3 is a timing diagram illustrating an exemplary multiple access point data transmission scheme 300 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. As shown in FIG. 3, an exemplary multiple access point data transmission scheme 300 is provided with a procedure of frequency domain joint transmission for wireless network with multi-APs. In a simplified embodiment, the procedure includes three portions in a timing diagram: 1) Channel sounding; 2) Trigger-based data transmission; 3) Block Acknowledgment (BA) report to AP.

[0039] In a context of wireless networking with multi-APs, one access point (API) is a device that acts as a central hub for wireless communication, defined as a master AP, and it can send frequency resources to other APs in its network. Other access points (AP2 or more) in the wireless network are referred to as satellite APs. One of multiple user devices in the wireless network may be defined as a station (STA). Referring to channel sounding portion of the FIG. 3, the channel sounding procedure is shown as a multi-access point (MAP) is triggered by a null data packet announcement (NDPA) frame sent by the master AP to other satellite APs and STA. The NDPA frame is a MAP specific NDPA used for figuring outchannel state information (CSI) of multiple wireless channels corresponding to the multi- APs, which can be differentiated with other NDPA types.

[0040] After receiving the NDPA frame from the master AP, e.g., API, the satellite APs, e.g., AP2, and the station, STA, respectively send clear-to-send (CTS) frames, which is control frame employed in the medium access control (MAC) layer protocol IEEE 802.11, in a first short interframe space (SIFS) time. CTS includes a control message used to prevent collisions between devices when transmitting data over the air. CTS messages are transmitted between devices in the network to coordinate the use of the wireless channel and ensure that multiple devices do not attempt to transmit data at the same time. The SIFS time is a difference in time between the first symbol of the response frame in the air and the last symbol of the received frame in the air. STA also sends CTS-to-self frame to clear the medium associated with all access points.

[0041] Then in another SIFS time, API and AP2 will simultaneously send out a null data packet (NDP) frame (to STA) which is used by STA to measure the quality of communication channels between APs and STA and calculate channel sounding feedback. In an embodiment, the NDP frame includes multiplexed spatial streams which are typically made orthogonal to each other, which means that they are arranged in a way that minimizes interference between the streams. This will be further addressed in later sections for illustrating an alternative joint transmission method provided in the present disclosure.

[0042] After another SIFS time, a beamforming report poll (BFRP) frame will be sent out by API and AP2 (both as transmitter) to pull beamforming feedback from STA (receiver) about the quality of the communication channel between thereof. The beamforming feedback, also referred to beamforming report (BFR) message or simply BF report, contains information used by the transmitter to adjust the beamforming parameters, such as the direction and width of the beam, in order to optimize the performance of the communication. By continuously sending BFRP messages and receiving BFR responses, the transmitter (such as API, AP2) and receiver (such as STA) can adapt the beamforming parameters in real-time to maintain optimal communication performance. In some embodiments, the satellite APs may not need to send the BFRP frame. But if it sends the BFRP, the BFRP sent by AP2 shall be the same as the BFRP sent by API (master AP).

[0043] After receiving the BFRP, STA will send out the BF report to both API and AP2 in another SIFS time. In the BF report, the feedback information contains the beamforming feedback for both API and AP2 (or other satellite AP if more than one satellite APs exist inthe multi-AP wireless network). STA measures the channel from API to STA, and measures the channel from AP2 to STA independently. Thus, the beamforming feedback from STA for both API and AP2 shall be independent of each other. For example, for each of API and AP2 having 4 antennas, the beamforming feedback from STA to API and to AP2 are different, each with a smaller matrix. This will avoid the stringent master-satellite AP synchronization requirement in coherent joint transmission of the conventional scheme.

[0044] After receiving the BF report from STA by the master AP, the procedure of the frequency domain joint transmission enters a trigger-based data transmission portion as shown in FIG. 3. The master AP (i.e., API) sends out a MAP trigger frame to initiate the MAP data transmission. The MAP trigger frame includes all the information for data transmission, such as modulation coding scheme (MCS), resource unit (RU) allocation, spatial stream information, and STA address, etc.

[0045] At a SIFS time after the reception of the MAP trigger frame, the satellite AP and STA send out a CTS and CTS-to-self frame respectively to clear the medium in the network. At another SIFS time after the CTS, data blocks will be sent by API and AP2 jointly to the STA respectively on different RUs. Master AP (API) sends a first data block on a first RU allocated to API and satellite AP (AP2) sends a second data block on a second RU allocated to AP2. The first data block and the second data block are respectively on different RUs and are independent. There are two options to send out the data jointly on different RUs. A first option is a transmission of data with independent coding and modulation on different RUs. API and AP2 can chose different MCS to encode / modulate their own data independently. In this way, the master AP will only need to forward the data (for the corresponding STA) that satellite AP needed instead of forwarding all the data. This is a scheme with partial data sharing which reduces the backhaul overhead. Another option is the transmission of data with joint coding and modulation on different RUs. Thus, API and AP2 encode / modulate data as if they are one AP. Both APs will choose the same MCS. Both AP need to have all the data of the corresponding STA. The benefit of this scheme is the STA will simply follow the existing receive procedure instead of taking care of independently coded RUs.

[0046] After the data transmission, the procedure of joint transmission according to embodiments of the present disclosure enters the Block Acknowledgement (BA) report to AP portion as shown in FIG. 3. Both API and AP2 can send a BA request (BAR) to the STA to ask STA to feedback a BA report for the data that respective APs sent to STA separately at a SIFS time after the BAR. Optionally, if both AP encode / modulate the data independently,the BA reports from the station in response to different BARs sent from different APs (could be at different time) are independent (could be reported at different time).

[0047] In an embodiment, the MAP trigger sent by the master AP in the trigger-based data transmission portion needs to indicate information to guarantee the data transmission between the two APs are symbol level aligned to maintain the orthogonality of the two data streams sent respectively by the two APs. For instance, MAP trigger needs to indicate the LENGTH of the data block such that the PPDU transmitted by both APs ends at the same symbol boundary. MAP trigger also needs to indicate both APs to choose the same guard interval for transmitting the data block by both API and AP2.

[0048] In the multiple access point data transmission scheme 300, i.e., frequency domain joint transmission in FIG. 3, the operating BW (bandwidth) of API and AP2 may or may not cover the frequency resources of the RU sent by the other AP. Figure 4 is a block diagram illustrating multiple access point data transmission schemes regarding the AP bandwidth coverage of RU’s frequency resources according to embodiments of the present disclosure. In an embodiment, as shown in Part A of FIG. 4, API and AP2 are 160MHz operating APs and operating in a same channel. During the MAP trigger-based data transmission, API only transmits on the first RU which has frequency resources of 80MHz and AP2 only transmits on the second RU which has also frequency resources of 80MHz. In this case, API’s operating BW, 160MHz, covers the frequency resources of 80MHz of the second RU; and AP2’s operating BW, 160MHz, also covers the frequency resources of 80MHz of the first RU. The effective BW of the data block is 160MHz in the joint transmission. In some embodiments, other suitable operating BW applies to API and / or AP2, such as 20MHz and 40MHz.

[0049] In another embodiment, as shown in Part (B) of FIG. 4, API and AP2 are 80MHz operating APs and operating in different channels. During the MAP trigger-based data transmission, API transmits on the first RU which has frequency resources of 80MHz and AP2 transmits on the second RU which has also frequency resources of 80MHz. In this case, API’s operating BW, 80MHz, doesn’t cover the frequency resources of 80MHz of the second RU; and AP2’s operating BW, 80MHz, doesn’t cover the frequency resources of 80MHz of the first RU either.

[0050] In yet another embodiment, as shown in Part (C) of FIG. 4, API and AP2 are 80MHz operating APs and operating respectively in two 80MHz channels with 40MHz overlapped with each other. During the MAP trigger-based data transmission, API transmitson the first RU which has frequency resources of 80MHz and AP2 transmits on the second RU which has frequency resources of 40MHz. In this case, API’s operating BW, 80MHz, doesn’t cover the frequency resources of 40MHz of the second RU; and AP2’s operating BW, 80MHz, covers part of the frequency resources of 80MHz of the first RU.

[0051] Note, although RU is used to illustrate the multi-AP joint transmission scheme of FIG. 3 and FIG. 4, each AP can also send data on multiple resource unit (MRU). MRU is a group of resources that can be used to transmit data. These resources may include different frequencies, time slots, or other types of physical resources that are used to transmit data. MRUs can be used in a variety of wireless communication technologies, including WiFi, cellular networks, and satellite systems. They are typically implemented through the use of advanced multiplexing techniques, which allow multiple data streams to be transmitted over the same physical resources by dividing the resources into smaller units and assigning them to different data streams.

[0052] Figure 5 is a timing diagram illustrating another exemplary multiple access point data transmission scheme 500 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. As shown in FIG. 5, another exemplary multiple access point data transmission scheme 500 is provided with a procedure of spatial domain joint transmission for wireless network with multi-APs. In another simplified embodiment, the procedure of the spatial domain joint transmission is mostly the same as the frequency domain joint transmission shown in FIG. 3 with three portions of time diagram including 1) Channel sounding; 2) Trigger-based data transmission; 3) Block Acknowledgment (BA) report to AP, except the portion of triggerbased data transmission. API and AP2 are transmitting data on different spatial streams instead of different RUs.

[0053] The spatial streams refer to the separate data streams that are transmitted over a wireless network using different antennas and spatial multiplexing techniques. In a wireless communication system that uses multiple antennas, each antenna can transmit a separate data stream, which is known as a spatial stream. The data streams transmitted by different APs can be encoded / modulated independently or be encoded / modulated jointly by different APs. The spatial streams holding the transmitting data are multiplexed in the NDP frame and must be orthogonal. Orthogonal refers to the property of two or more vectors being perpendicular to each other. In the context of wireless communication, orthogonal spatial streams are those that are transmitted over separate antennas and are perpendicular to each other in the spatialdomain. This means that the spatial streams do not interfere with each other and can be reliably received at the receiver. The orthogonality could also be achieved by using orthogonal coded in the time domain.

[0054] If different APs encode / modulate data independently on different spatial streams, different AP chose different MCS on the corresponding spatial stream. The master AP only needs to forward a portion of the data to the satellite AP, i.e., partial data sharing is needed. This option may reduce the backhaul overhead.

[0055] If different APs encode / modulate data jointly on different spatial streams, different APs shall choose the same MCS on the corresponding spatial stream. The master AP needs to forward all the data to the satellite AP, i.e., whole data sharing is needed.

[0056] In an embodiment, the MAP trigger sent by the master AP in the trigger-based data transmission portion needs to indicate information to guarantee the data transmission between the two APs are symbol level aligned to maintain the orthogonality of the two data streams sent respectively by the two APs. For instance, MAP trigger needs to indicate the LENGTH of the data block such that the PPDU transmitted by both APs ends at the same symbol boundary. MAP trigger also needs to indicate both APs to choose the same guard interval for transmitting the data block by both API and AP2.

[0057] Figure 6 is a timing diagram illustrating yet another exemplary multiple access point data transmission scheme 600 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. As shown in FIG. 6, another exemplary multiple access point data transmission scheme 600 is provided with a procedure of duplicated joint transmission for wireless network with multi - APs. In yet another simplified embodiment, the procedure of the duplicated joint transmission is mostly the same as the frequency domain joint transmission shown in FIG. 3 with three portions of time diagram including 1) Channel sounding; 2) Trigger-based data transmission; 3) Block Acknowledgment (BA) report to AP, except both APs transmit the same encoded data. In other words, at a SIFS time after the CTS frame is being sent by the AP2 and STA, both API and AP2 transmit the same encoded data. The gain comes from the data transmitting power. This option requires data sharing between the master AP (API) and the satellite AP (AP2). AP2 mirrors whatever is sent by API. The PPDU data block will be sent with higher transmitting power under the duplicated joint transmission with multi-APs comparing with single AP.

[0058] In an embodiment, the MAP trigger sent by the master AP in the trigger-based data transmission portion needs to indicate information to guarantee the data transmission between the two APs are symbol level aligned to maintain the orthogonality of the two data streams sent respectively by the two APs. For instance, MAP trigger needs to indicate the LENGTH of the data block such that the PPDU transmitted by both APs ends at the same symbol boundary. MAP trigger also needs to indicate both APs to choose the same guard interval for transmitting the data block by both API and AP2.

[0059] Although in FIG. 3, FIG. 5, and FIG. 6 only two APs are used to illustrate the three embodiments of the joint transmission scheme for multi-AP networks, the same joint transmission scheme can be applied to cases with more than two APs. Among those APs, one is the master AP and the rest are the satellite APs.

[0060] Figure 7 is a simplified flow diagram of a multiple access point data transmission method 700 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. Figure 7 is divided into two portions, FIG. 7A and FIG. 7B, in separate pages. Method 700 for multiple access point joint data transmission is provided within a context of wireless networking with multi-APs for frequency domain joint transmission. A first access point (API) acts as a central hub for wireless communication, defined as a master AP, and it can send frequency resources to other APs in its network. A second access point (AP2) in the wireless network is referred to as a satellite AP. One of the multiple user devices in the wireless network may be defined as a station (STA). Method 700 in FIG. 7A portion includes step 702 to generate a null data packet announcement (NDPA) frame for multiple access point (MAP) communication by the first access point API . The (NDPA) frame is a type of control frame used in 802.11 wireless networks to transmit a null data packet to a station, indicating that the station is permitted to transmit on the channel. Method 700 in FIG. 7A portion includes step 704 to transmit wirelessly the null data packet announcement frame to trigger a sounding process for the first access point API and a second access point AP2. The sounding process may start at a short interframe space (SIFS) time after transmitting the NDPA frame. The SIFS time is a difference in time between the first symbol of the response frame in the air and the last symbol of the received frame in the air.

[0061] In the sounding process, a first channel state information is sent from the second access point AP2 and a second channel state information is sent from the station (STA). The channel state information contains clear to send (CTS) message for controlling the wirelessnetwork devices (including the access points and user devices for typical WiFi networks) to prevent transmission collisions and improve the efficiency of data transmission.

[0062] Referring to FIG. 7A, method 700 additionally includes step 710 to transmit a first null data packet (ND A) and a second NDA to the station (STA) respectively by the first access point and the second access point simultaneously at a SIFS time after the sounding process. In a specific embodiment, the first NDA is used by the STA to measure the quality of communication channels between API and STA and the second null data NDA is used by the STA to measure the quality of communication channels between AP2 and STA and calculate channel sounding feedback. The timing of performing step 710 is at a SIFS time after the sounding process. Method 700 in FIG. 7A portion further includes step 712 to transmit a first beamforming report poll to the station STA by the first access point API to ask STA for feedback for the API. Optionally, the second access point AP2 also sends a second beamforming report poll to the station to ask STA for feedback for the AP2.

[0063] Referring to FIG. 7A again, method 700 includes step 714 to receive a feedback generated by the station STA in response to the first beamforming report poll. The feedback is a beamforming feedback (BF) report including a first beamforming feedback for API about the quality of the communication channel between the API and STA using the first null data NDA from API, and independently a second beamforming feedback for AP2 about the quality of the communication channel between the AP2 and STA using the second null data NDA from AP2. This will avoid the stringent master-satellite AP synchronization requirement in coherent joint transmission of the conventional scheme.

[0064] Referring to FIG. 7B, which is another portion of Figure 7 following the FIG. 7A, method 700 also includes step 716 to generate by the first access point API (i.e., the master AP) a MAP trigger signal that will be used for initiating a trigger-based data transmission, as seen in FIG. 3. The MAP trigger signal includes all the information for data transmission, such as modulation coding scheme (MCS), resource unit (RU) allocation, spatial stream information, and STA address, etc. Method 700 then includes step 718 to transmit by the first access point API the MAP trigger signal to initiate a MAP data transmission process.

[0065] Referring to FIG. 7B again, method 700 further includes step 720 to receive a channel state information separately from the station STA and the second access point AP2 in response to the MAP trigger signal. Step 720 may start at a SIFS time after transmitting the MAP trigger signal at step 718. The channel state information again contains clear to send (CTS) message for the first access point API or the second access point AP2. The MAPtrigger signal contains information of allocation of a first resource unit (RU) for the API to transmit data and a second resource unit (RU) for the AP2 to transmit data.

[0066] Then method 700 includes step 722 to transmit a first data block on a first resource unit (RU) to the station by the first access point API and a second data block on a second RU to the station by the second access point AP2. Step 722 may start at a SIFS time after step 720. The first RU is different from the second RU. Optionally, the first data block and the second data block are independently coded and modulated on the two different RUs. API and AP2 can choose different MCS to encode / modulate the first data block and the second data block, respectively. API, the master AP, only needs to forward partial data (for the STA) that AP2, the satellite AP, needed instead of forwarding all the first data block to reduce backhaul overhead. Optionally, the first data block and the second data block are jointly coded and modulated on the two different RUs. API and AP2 choose the same MCS to encode / modulate data as if they are one AP. Both APs then need to have all the data of the corresponding STA.

[0067] Referring to FIG. 7B again, method 700 includes step 724 to send a first block acknowledgement request (BAR) from the first access point API to the station STA. Furthermore, method 700 may include sending a first block acknowledgement (BA) from the station STA to the first access point API; sending a second block acknowledgement request (BAR) from the second access point AP2 to the station STA; and sending a second block acknowledgement (BA) from the station STA to the second access point AP2. Optionally, sending the first BAR by API and sending the second BAR by AP2 can be performed at different times. Sending the first BA by the STA is at a SIFS time after sending the first BAR by API and sending the second BA by the STA is at a SIFS time after sending the second BAR by AP2. In an embodiment, implementation of method 700 in a multi-AP wireless network is illustrated in a simplified timing diagram shown in FIG. 3.

[0068] Figure 8 is a simplified flow diagram of another multiple access point data transmission method 800 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. Figure 8 is divided into two portions, FIG. 8A and FIG. 8B, in separate pages. Method 800 for multiple access point joint data transmission is provided as an alternative embodiment of method 700 within the context of similar wireless networking with multi-APs for spatial domain joint transmission. Method 800 in FIG. 8 A portion includes multiple steps that are substantially the same as steps in Method 700 in FIG. 7A portion.

[0069] As shown in FIG. 8A, Method 800 includes step 802 to generate a null data packet announcement frame (a NDPA frame) for multiple access point (MAP) communication by the first access point API (a master AP). Method 800 also includes step 804 to transmit wirelessly the null data NDPA frame by the API to a second access point AP2 (a satellite AP) and a station STA to trigger a channel calibration process. The NDPA frame contains an address of the STA. Additionally, method 800 includes step 808 to transmit a first channel state information and a second channel state information respectively by the second access point API and the station STA in the channel calibration process. Method 800 further includes step 810 to transmit two null data packets (ND As) simultaneously by the first access point and the second access point at a short interframe space (SIFS) time after receiving the first channel state information and the second channel state information. Method 800 also includes step 812 transmit a first beamforming report poll to the station STA by the first access point API to ask STA for a feedback for the API. Step 812 starts at a SIFS time after step 810. Optionally, the second access point AP2 also sends a second beamforming report poll to the station STA to ask STA for a feedback for the AP2. Method 800 further includes step 814 to receive a feedback in response to the first beamforming report generated by the station STA. The feedback is a beamforming feedback report including a first beamforming feedback for API about the quality of the communication channel between the API and STA using a first null data ND A from API, and independently a second beamforming feedback for AP2 about the quality of the communication channel between the AP2 and STA using a second null data NDA from AP2. Step 814 starts at a SIFS time after step 812.

[0070] Method 800, moving to FIG. 8B, which is another portion of Figure 8 following the FIG. 8A, also includes step 816 to generate by the first access point API (i.e., the master AP) a MAP trigger signal that will be used to initiate a trigger-based data transmission, as seen in FIG. 5. The MAP trigger includes all the information for data transmission, such as modulation coding scheme (MCS), resource unit (RU) allocation, spatial stream information, and STA address, etc. Method 800 then includes step 818 to transmit by the first access point API the MAP trigger signal to initiate a MAP data transmission process. Method 800 further includes step 820 to send a third channel state information by the second channel access point AP2 and a fourth channel state information by the station STA in response to the MAP trigger signal. The third or fourth channel state information contains clear-to-send (CTS) message for the first access point API or the second access point AP2. The MAP trigger signal contains independent spatial stream information for the API to use for transmitting data and for the AP2 to use for transmitting data. Step 820 starts at a SIFS time after transmitting the MAP trigger signal.

[0071] Then method 800 includes step 822 to transmit a first data block on a first spatial stream to the station STA by the first access point API and a second data block on a second spatial stream to the station STA by the second access point, and step 824 to transmit a second data block on a second spatial stream to the station STA by the second access point AP2. The second spatial stream is different from the first spatial stream. The data streams transmitted by different APs can be encoded / modulated independently or be encoded / modulated jointly by different APs. If different APs encode / modulate data independently on different spatial streams, different AP chose different MCS on the corresponding spatial stream. Method 800 may include forwarding a portion of data from the first access point API to the second access point AP2. If different APs encode / modulate data jointly on different spatial streams, different APs shall choose the same MCS on the corresponding spatial stream. Method 800 may include forwarding an entirety of data from the first access point API to the second access point AP2. Furthermore, method 800 includes step 826 to send a first block acknowledgement request (BAR) from the first access point API to the station STA. In an embodiment, implementation of method 800 in a multi-AP wireless network is illustrated in a simplified timing diagram shown in FIG. 5.

[0072] Figure 9 is a simplified flow diagram of yet another multiple access point data transmission method 900 according to embodiments of the present disclosure. This diagram is merely an example, which should not unduly limit the scope of the claims. One of the ordinary skills in art would recognize many variations, alternatives, and modifications. Figure 9 is divided into two portions, FIG. 9A and FIG. 9B, in separate pages. Method 900 for multiple access point joint data transmission is provided as another alternative embodiment of method 700 within the context of similar wireless networking with multi-APs for duplicated joint transmission. Method 900 in FIG. 9A portion includes multiple steps that are substantially the same as steps in Method 700 in FIG. 7A portion.

[0073] As shown in FIG. 9A, Method 900 includes step 902 to generate a null data packet announcement frame (a NDPA frame) for multiple access point (MAP) communication by a master access point APIMethod 900 also includes step 904 to transmit wirelessly the null data NDPA frame by the master API to a satellite access point AP2 and a statin STA to trigger a channel calibration process. Additionally, method 900 includes step 906 to transmit a first clear-to-send (CTS) frame and a second CTS frame respectively by the satellite access point AP2 and the station STA in the channel calibration process. Step 906 starts at a SIFS time after step 904. Method 900 further includes step 910 to transmit two null data packets (ND As), a first NDA and a second ND A, simultaneously and respectively by the masteraccess point API and the satellite access point AP2 at a SIFS time after the channel calibration process. Method 900 also includes step 912 transmit a first beamforming report poll to the station STA by the master access point API to ask STA for generating a feedback for the API. Optionally, the satellite access point AP2 also sends a second beamforming report poll to the station to ask STA for feedback for the AP2. Method 900 further includes step 914 to receive a feedback generated by the station STA in response to the first beamforming report poll. Step 914 starts at a SIFS time after step 912.

[0074] Referring to FIG. 9B, which is another portion of Figure 9 following the FIG. 9A, method 900 also includes step 916 to generate by the master access point API a MAP trigger signal that will be used to initiate a trigger-based data transmission, as seen in FIG. 6.Method 900 then includes step 918 to transmit by the master access point API the MAP trigger signal to initiate a MAP data transmission process. The MAP trigger signal includes all the information for data transmission, such as modulation coding scheme (MCS), resource unit (RU) allocation, spatial stream information, and STA address, etc. The MAP trigger signal needs to indicate information to guarantee the data transmission between the two APs are symbol level aligned to maintain the orthogonality. Method 900 further includes step 920 to send a third CTS frame by the satellite access point AP2 and a fourth CTS frame by the station STA in response to the MAP trigger signal. The third CTS frame contains channel state message for the master access point API . The fourth CTS frame contains channel state message for the satellite access point AP2. MAP trigger signal generated by the master API needs to indicate the LENGTH of the data block such that the data block transmitted by both APs ends at the same symbol boundary. MAP trigger signal also needs to indicate both APs to choose the same guard interval. Method 900 also includes step 922 to align a first symbol transmission of the master access point API to a second symbol transmission of the satellite access point AP2. Method 900 also includes step 924 to transmit a duplicated data block by the master access point API and by the satellite access point AP2 together to the station STA. The gain of this method for transmitting duplicate data comes from an enhanced transmit power. Method 900 may further include sending a first block acknowledgement request (BAR) from the master access point API to the station STA. In an embodiment, implementation of method 900 in a multi-AP wireless network is illustrated in a simplified timing diagram shown in FIG. 6. Note that although two APs are referred in the three methods 700, 800, and 900 in this disclosure, these methods can be implemented for any multi-AP wireless network with more than two APs to perform joint transmission. Among those APs, one is the master AP and the rest are the satellite APs.

[0075] In one exemplary aspect, the present disclosure relates to a method for wireless communication. The method includes generating a null data packet announcement frame for multiple access points (MAP) communication by a first access point, transmitting wirelessly the null data packet announcement frame to trigger a sounding process for the first access point and a second access point, transmitting a first null data packet and a second null data packet to a station respectively by the first access point and the second access point simultaneously at a short interframe space (SIFS) time, transmitting a first beamforming report poll to the station by the first access point, receiving a feedback generated by the station in response to the first beamforming report poll, the feedback containing a first beamforming feedback for the first access point and a second beamforming feedback for the second access point, the first beamforming feedback being independent of the second beamforming feedback, generating by the first access point a MAP trigger signal, transmitting by the first access point the MAP trigger signal to initiate a MAP data communication process, allocating a first set of frequency resources to a first resource unit to the station by the first access point and allocating a second set of frequency resources to a second resource being different from the first resource unit, and sending a first block acknowledgement request from the first access point to the station. The first resource unit and the second resource unit are transmitted to the station.

[0076] In another exemplary aspect, the present disclosure relates to a method for wireless communication. The method includes generating, by a first access point, a multiple access points (MAP) trigger signal, transmitting, by the first access point, the MAP trigger signal to initiate a MAP data communication process, transmitting first data on a first spatial stream to the station by the first access point, transmitting second data on a second spatial stream to the station by the second access point, the second spatial stream being different from the first spatial stream, and sending a first block acknowledgement request from the first access point to the station.

[0077] In yet another exemplary aspect, the present disclosure relates to a method for wireless communication. The method includes generating a null data packet announcement frame for multiple access points (MAP) communication in a wireless network by a master access point, transmitting wirelessly the null data packet announcement frame to trigger a sounding process, transmitting a first clear-to-send (CTS) frame and a second CTS frame respectively by a satellite access point and a station in the sounding process, transmitting two null data packages simultaneously and respectively by the master access point and the satellite access point at a short interframe space (SIFS) time after the sounding process,transmitting a first beamforming report poll frame to the station by the master access point, receiving feedback generated by the station in response to the first beamforming report poll frame, generating by the master access point a MAP trigger signal, transmitting by the master access point the MAP trigger signal to initiate a MAP data communication process, sending a third CTS frame by the satellite access point and sending a fourth CTS frame by the station in response to the MAP trigger signal, aligning a first symbol transmission of the master access point to a second symbol transmission of the satellite access point, and transmitting duplicated data by the master access point and by the satellite access point.

[0078] While the above is a full description of the specific embodiments, various modifications, alternative constructions and equivalents may be used. Therefore, the above description and illustrations should not be taken as limiting the scope of the present disclosure which is defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for wireless communication, the method comprising: generating a null data packet announcement frame for multiple access points(MAP) communication by a first access point; transmitting wirelessly the null data packet announcement frame to trigger a sounding process for the first access point and a second access point; transmitting a first null data packet and a second null data packet to a station respectively by the first access point and the second access point simultaneously at a short interframe space (SIFS) time; transmitting a first beamforming report poll to the station by the first access point; receiving a feedback generated by the station in response to the first beamforming report poll, the feedback containing a first beamforming feedback for the first access point and a second beamforming feedback for the second access point, wherein the first beamforming feedback is independent of the second beamforming feedback; generating by the first access point a MAP trigger signal; transmitting by the first access point the MAP trigger signal to initiate a MAP data communication process; allocating a first set of frequency resources to a first resource unit to the station by the first access point and allocating a second set of frequency resources to a second resource being different from the first resource unit, wherein the first resource unit and the second resource unit are transmitted to the station; and sending a first block acknowledgement request from the first access point to the station.

2. The method of claim 1 further comprising receiving a channel state information separately from the station and the second access points in response to the MAP trigger signal.

3. The method of claim 1 wherein the first access point acts as a master access point and the second access point acts as a satellite access point.

4. The method of claim 1 further comprising measuring a first channel characteristic from the first access point to the station to report in the first beamforming feedback by the station in response to the first beamforming report poll and independentlymeasuring a second channel characteristic from the second access point to the station to report in the second beamforming feedback by the station in response to the second beamforming report poll.

5. The method of claim 1 further comprising transmitting a second beamforming report poll to the station by the second access point.

6. The method of claim 1 wherein the MAP trigger signal includes modulation coding scheme, resource allocation information, and spatial stream information.

7. The method of claim 1 further comprising sending a first block acknowledgement from the station to the first access point.

8. The method of claim 7 further comprising: sending a second block acknowledgement request from the second access point to the station; sending a second block acknowledgement from the station to the second access point.

9. A method for wireless communication, the method comprising: generating, by a first access point, a multiple access points (MAP) trigger signal; transmitting, by the first access point, the MAP trigger signal to initiate a MAP data communication process; transmitting first data on a first spatial stream to the station by the first access point; transmitting second data on a second spatial stream to the station by the second access point, the second spatial stream being different from the first spatial stream; and sending a first block acknowledgement request from the first access point to the station.

10. The method of claim 9 wherein the first spatial stream and the second spatial stream are associated with different modulation coding schemes (MCS).

11. The method of claim 10 further comprising forwarding a portion of data from the first access point to the second access point.

12. The method of claim 9 wherein the first spatial stream and the second spatial stream are associated with a same modulation coding scheme (MCS).

13. The method of claim 12 further comprising forwarding an entirety of data from the first access point to the second access point.

14. A method for wireless communication, the method comprising: generating a null data packet announcement frame for multiple access points(MAP) communication in a wireless network by a master access point; transmitting wirelessly the null data packet announcement frame to trigger a sounding process; transmitting a first clear-to-send (CTS) frame and a second CTS frame respectively by a satellite access point and a station in the sounding process; transmitting two null data packages simultaneously and respectively by the master access point and the satellite access point at a short interframe space (SIFS) time after the sounding process; transmitting a first beamforming report poll frame to the station by the master access point; receiving feedback generated by the station in response to the first beamforming report poll frame; generating by the master access point a MAP trigger signal; transmitting by the master access point the MAP trigger signal to initiate a MAP data communication process; sending a third CTS frame by the satellite access point and sending a fourth CTS frame by the station in response to the MAP trigger signal; aligning a first symbol transmission of the master access point to a second symbol transmission of the satellite access point; and transmitting duplicated data by the master access point and by the satellite access point.

15. The method of claim 14 further comprising sending a first block acknowledgement request from the master access point to the station.

16. The method of claim 14, wherein transmitting the duplicated data comprises transmitting a same encoded data and sharing the same encoded data between the master access point and the satellite access point.

17. The method of claim 16 wherein the master access point and the satellite access point are configured orthogonally for transmitting the duplicated data.

18. The method of claim 14 wherein the MAP trigger signal comprises a length information of data to be transmitted so that the duplicated data transmitted by both the master access point and the satellite access point ends at a same symbol boundary.

19. The method of claim 14 wherein the MAP trigger signal comprises a guard interval for transmitting the duplicated data block by both the master access point and the satellite access point.

20. The method of claim 14 further comprising null data extending the MAP communication to additional satellite access points in the wireless network.

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