Patent Description:
Wi-Fi technology has demonstrated substantial growth since the inception in <NUM> of the <NUM> Project Authorization Request to develop medium access control and physical layer specification for wireless connectivity. The growth of Wi-Fi technology corresponds to increased Wi-Fi traffic driven by increases in the number of users, increasing data rates, and increases in the amount of data sent and received. Although Wi-Fi traffic continues to expand, the ability of Wi-Fi technology to meet the traffic demands is limited by available bandwidth. Wi-Fi operates on specific frequency bands that are shared by STAs and scheduled by APs. The next generation of Wi-Fi technology will rely on developments in scheduling traffic to reduce overhead and increase the amount of data that can be transferred.

The transmission of data within a Wi-Fi network is facilitated by APs. APs are devices that schedule the transmission of data to and from STAs. STAs are devices that use data sent over the Wi-Fi network to carry out specific tasks. Some examples of STAs include personal computers, cellular phones, and servers. Because Wi-Fi transmission are not bound to cables or wires, each STA is unaware of transmission by other STAs and each STA tends to be unaware of the busy/idle state of the APs. In early Wi-Fi development, the situation arose where each STA would transmit a data frame simultaneously to an AP. With each STA transmitting a data frame at the same time the AP is overwhelmed and would be unable to capture any single data frame. At the same time that the AP is overwhelmed, it is also underutilized because the AP does not have any data frames from any STAs to manage. This problem became known as collision.

To avoid constant collision of data frames, Wi-Fi STAs transmit a data frame and wait for an acknowledgement from the intended receiver that the data frame was received. If no acknowledgement is received, the STA can send the transmission again. The STA will repeatedly send transmission until an acknowledgement is received. There is a cost to repeatedly transmitting frames. Each retransmission attempt results in longer wait times between retransmissions that compound creating greater and greater overhead costs. The embodiments described herein are directed to a device, method, and computer readable medium that reduce collisions and reduce overhead that plague current Wi-Fi communications. Document <CIT> discloses an IEEE <NUM>. 11ax system, with multiple, simultaneous uplink transmissions from STAs and it represents an example of the prior art.

So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, maybe had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted that the appended drawings illustrate typical embodiments and are therefore not to be considered limiting; other equally effective embodiments are contemplated.

One embodiment presented in this disclosure is an AP that includes a transmitter configured to broadcast a trigger message to a plurality of STAs, the trigger message including a matrix defining a plurality of resource units (RUs) that the plurality of STAs are assigned in order to transmit or receive data simultaneously for a fixed duration. The matrix further defining a first timeslot in a first RU of the plurality RUs that is assigned to a first one of the plurality of STAs and a second timeslot in the first RU that is assigned to a second one of the plurality of STAs.

Another embodiment presented in this disclosure is a method that includes transmitting a trigger message to a plurality of STAs, the trigger message comprising a matrix defining a plurality of RUs that the plurality of STAs are assigned to transmit data simultaneously for a fixed duration, the matrix further defining a first timeslot in a first RU of the plurality RUs that is assigned to a first one of the plurality of STAs and a second timeslot in the first RU that is assigned to a second one of the plurality of STAs. The method also includes receiving data from the STAs using the RUs defined in the matrix.

Another embodiment presented in this disclosure is a computer product comprising logic encoded in a non-transitory medium, the logic executable by operation of one or more computer processors to perform an operation. The operation includes transmitting a trigger message, from an AP, to a plurality of STAs, the trigger message comprising a matrix defining a plurality of RUs that the plurality of STAs are assigned to transmit or receive data simultaneously for a fixed duration, the matrix further defining a first timeslot in a first RU of the plurality RUs that is assigned to a first one of the plurality of STAs and a second timeslot in the first RU that is assigned to a second one of the plurality of STAs.

Wi-Fi communication includes extensive overhead to coordinate the movement of data among STAs and APs. For example, Wi-Fi systems can use clear to send (CTS) messages, request to send (RTS) messages, and acknowledge messages to co-ordinate data transmissions. A CTS message is transmitted by a STA in response to a RTS message. The CTS message silences all wireless STAs in its vicinity and enables the sender of the RTS message to begin data transfer. The cost of this solution is large overhead. Sending CTS messages, RTS messages, and acknowledge messages costs time and bandwidth. Each message increases the amount of time consumed prior to sending an actual data frame. Also, the transmission of each message and the processing of the received message by the recipient consumes memory space, processor resources, and electrical energy. In today's world of constant connection, digital downloads, and social media these costs impose real penalties on the ability of WIFI networks to meet the demands of data transmission networks.

The embodiments described herein overcome these inefficiencies by deterministically transferring data. A time-division and frequency division scheduling matrix allows for the deterministic transfer of data. This flexible scheduling matrix provides complete information to an AP that details the STA that is sending an amount of data and when that data will be sent. Therefore, the deterministic scheduling matrix fully defines when a data packet will arrive at an AP, the time when the data packet will arrive, and the resource unit (RU) carrying the data packet. The embodiments described herein increase the flexibility and density of data frames, eliminating overhead, and provide greater reliability.

<FIG> illustrates a non-deterministic downlink transmission <NUM>. A non-deterministic transmission is a Wi-Fi transmission where the AP and STAs are not given a scheduling defining data transmissions by time and RU. Current Wi-Fi communication hardware relies on non-deterministic devices and methods to facilitate communication between STAs and APs. Non-deterministic down-link transmission <NUM> includes a multi-user request to send (MU-RTS) message <NUM>, a CTS message <NUM>, a header <NUM>, multi-user download frame <NUM>, and a block acknowledgement <NUM>.

For non-deterministic downlink transmission <NUM>, an AP can first send a MU-RTS <NUM>, indicating for each target STA (STA-<NUM>, STA-<NUM>, STA-<NUM>, etc.) the RU <NUM>-<NUM> thru <NUM>-<NUM> the AP is going to use to transmit. For example, for target STA <NUM> (STA-<NUM>) the AP is going to transmit on RU <NUM>-<NUM>. For example, a RU is a specific amount of frequency bandwidth that is allocated to a particular wireless device for communication.

The target STAs respond in parallel in a multi-user response, indicating CTS <NUM> to acknowledge the announced downstream transmission. The AP then sends a multi-user downlink frame <NUM> with the target data in the announced resource for each STA. The target data (e.g., target data <NUM>) consumes the entire RU allocated for each STA. For example, the target data <NUM> for RU <NUM>-<NUM> utilizes the entire resource <NUM> for RU <NUM>-<NUM> assigned for multi-user data frame <NUM>. The entire time period allocated to the RU for the data frame is allocated to a single STA. Although in this example a STA is allocated the full time for a RU, a STA can be allocated a division of the frequency bandwidth. For example, within data frame <NUM>, data for STA <NUM><NUM> and data for STA <NUM><NUM> are allocated bandwidth of the RU that is split by frequency but occupies the entire timeslot. The data for STA <NUM> and STA <NUM> cannot occupy less than the full time for RU <NUM>-<NUM>. After the transmission completes, the AP sends a block acknowledgement request (not depicted) to confirm if each client received the transmission successfully. If the data frames were received successfully, the clients respond with a block acknowledgement <NUM> in parallel. For non-deterministic downlink transmission, the MU-RTS <NUM>, CTS <NUM>, block acknowledgement request, and block acknowledgement are overhead consuming system resources, bandwidth, and time.

<FIG> illustrates non-deterministic uplink transmission <NUM>. For non-deterministic uplink transmissions <NUM>, an AP is expected to first obtain the BSR <NUM> for all STAs. The BSR <NUM> can be sent individually by each STA with a single user uplink frame. In this example, the single user uplink frame consumes the entire channel. The BSR can also be clubbed in another uplink aggregate MAC protocol data unit (AMPDU). The AP can also send a request to a set of target STAs (BSR Poll) <NUM>, allocating to each one a RU <NUM> to return their BSR <NUM>. In one unclaimed embodiment, the STAs respond in parallel in a MU-RTS response <NUM>.

The AP then knows which STA has which traffic to send. In response, the AP sends a MU-RTS frame <NUM> to the target clients, with the allocation of RUs <NUM> for their data transmission. All STAs respond in parallel in a multi-user response, indicating CTS <NUM> to acknowledge the allocated upstream RUs. The AP then sends a trigger frame <NUM> to start each client transmission. The target clients can respond in parallel with data in their respective RU <NUM>. If the data frames were received successfully, the AP responds with a group block acknowledgement <NUM>. Each of the BSR Poll <NUM>, the BSR <NUM>, the MU-RTS <NUM>, CTS <NUM>, and trigger frame <NUM> represent overhead consuming time and bandwidth.

In a non-deterministic system, uplink (UL) and downlink (DL) transmissions require multiple rounds of transmission creating inefficiencies and wasting resources. This occurs because the size of the STA transmission is not known to the AP. The coordination of non-deterministic systems, therefore, includes a large overhead to communicate the data that is sent. This overhead includes communication in the form buffer status report polling (BSRP), BSR, MU-RTS, CTS, and a trigger message. Embodiments herein improve both UL and DL transmissions by eliminating overhead, reducing congestion losses, and decreasing jitter.

<FIG> illustrates deterministic data communication, according to one embodiment. The devices and methods described herein are designed to overcome the inflexibility, inefficiencies, and problems of current WIFI communications. The embodiment described herein includes an optional MU-RTS trigger <NUM>, an optional CTS message <NUM>, and a matrix <NUM>. The MU-RTS trigger <NUM> may be separated from the CTS message <NUM> by a short inter-frame space (SIFS) <NUM> and <NUM>. SIFS denote the amount of time in microseconds used by a wireless interface to process a received frame. The CTS message <NUM> may also be separated from the matrix <NUM> by a second SIFS <NUM>. Timeslots can be assigned to one STA in isolation or in sequence. When timeslots are assigned in sequence, the STA can transmit continuously from one timeslot to another, without stopping the transmission.

The embodiments herein reduce overhead and improve the efficiency of data frame transmission. The time and frequency matrix <NUM> includes a plurality of time windows, aligned in a time division multiplexing (TDM) fashion. Each time window includes time offsets. The size of the time offsets corresponds with an amount of time used to transmit the corresponding data frame. The embodiments described herein are not limited to a single offset size. This allows the embodiments described herein to customize the size of the timeslot to the size of the data frame. RUs <NUM>-<NUM> denote groups of bandwidth subcarriers (tones). Therefore, the matrix <NUM> has a height described by a plurality of RUs <NUM>-<NUM> and a width described by time. Although <FIG> denotes four RUs, the number of RUs within the matrix depends upon the bandwidth of the transmission signal. For example, there may be a maximum of <NUM> RUs for <NUM> bandwidth and <NUM> RUs for <NUM> bandwidth. Further divisions of bandwidth into RUs are defined in IEEE <NUM>. Thus the AP can schedule several consecutive transmit (XMIT) opportunities (TXOPs) with a single trigger frame.

The matrix <NUM> is a two-dimensional deterministic data frame for transmitting data. MU-RTS trigger <NUM> includes a schedule for transmitting the data that corresponds to matrix <NUM>. The schedule for sending a data frame from one or more APs and for receiving a data frame by one or more APs is transmitted as a MU-RTS trigger. The schedule corresponding with the matrix <NUM> is shared between receiving and transmitting APs to coordinate the transmission of data. Accordingly, the MU-RTS trigger <NUM> reflects the content and size of a corresponding data frame described by matrix <NUM>.

The matrix <NUM> has depth <NUM> and width <NUM>. The matrix's depth <NUM> is measured in frequency (MHz). The frequency division reflects the bandwidth for each RU <NUM>-<NUM>. For example, each of RUs <NUM>-<NUM> may be a <NUM> band. Additional bands for RUs <NUM>-<NUM> such as <NUM>, <NUM>, and <NUM> (<NUM>+<NUM>) MHz can also be utilized.

Each of the RUs <NUM>-<NUM> can be further sub-divided by frequency into smaller frequency bands. For example, the first matrix entry <NUM> for RU <NUM> is sub-divided into a first smaller frequency band <NUM> and a second smaller frequency band <NUM>.

RUs <NUM>-<NUM> can also be further sub-divided into individual timeslots. For example, RU <NUM> schedules timeslot Data <NUM> for STA <NUM><NUM> at a first time period, timeslot Data <NUM> for STA <NUM><NUM> at the next time period, and a third timeslot <NUM> where no data transmission is scheduled. Each timeslot is separated by a micro-inter frame space (µIFS) <NUM>. Together Data <NUM> for STA <NUM><NUM>, Data <NUM> for STA <NUM><NUM>, the µIFSs <NUM>, and the empty set timeslots consume the allocated resource for RU <NUM>.

The schedule and corresponding matrix <NUM> allows flexibility with response to a size of the data packets and the corresponding timeslot that can be transmitted. This permits the AP to schedule a data packet for a particular STA that is less than the entire time allocated to the RU. The schedule and matrix <NUM> include subdivisions for each RU. For example, the time scheduled for Data <NUM> for STA <NUM> is less time than Data <NUM> for STA <NUM><NUM> scheduled in RU <NUM>. In contrast, the transmission schemes illustrated in <FIG> and <FIG> would utilize the entire time period allotted to RU <NUM> to transmit or receive Data <NUM> for STA <NUM>. Similarly, the transmission illustrated in <FIG> and <FIG> would require Data <NUM> for STA <NUM> to consume the entire time allotted to RU <NUM>. Therefore, matrix <NUM> defines a schedule for data transmission where data packets are assigned both a RU and timeslot in a more efficient manner permitting a single data frame to be more densely packed with data and allowing a greater number of data packets to be sent.

Because the schedule for the transfer of data transmitted before the data is transferred, the receiving AP can identify each data packet as it arrives by the time of arrival and the RU it arrives on. Similarly, a sending AP can have a matching schedule that permits it to synchronize the transmission of the data, according to the scheduling matrix. When the schedule is received by an AP that will receive the data scheduled by matrix <NUM>, the AP has a complete picture of the sequences of data, when each data packet will arrive, and the RU that will send the data. Therefore, each AP is able to efficiently and effectively coordinate the sending and receiving of data packets without the BSR polls <NUM>, BSRs <NUM>, and trigger frame <NUM>. In one unclaimed embodiment, the matrix <NUM> operates as a pull-trigger that lists traffic the AP receives and the time the traffic arrives at the AP. The matrix <NUM> indicates to the AP which RU and a time offset for the flow of data packets arriving at the AP according to the deterministic schedule included with MU-RTS trigger <NUM>.

For example, <FIG> depicts a consecutive timeslot transmission for STA <NUM>. Data for STA <NUM><NUM> occupies a single RU spanning the width of the time and frequency matrix <NUM>. <FIG> also depicts a non-contiguous transmission for STA <NUM>. Data <NUM> for STA <NUM><NUM> is non-contiguous with respect to time with Data <NUM> for STA <NUM><NUM>, and is not contiguous with respect to time with Data <NUM> for STA <NUM><NUM>. Note that the data for STA <NUM> is also non-contiguous in both time and frequency. Data <NUM> for STA <NUM><NUM> occupies a different RU from Data <NUM> for STA <NUM><NUM> and from Data <NUM> for STA <NUM><NUM>. The present disclosure permits division of scheduling for any STA with respect to both time and frequency. This allows for a more efficient data transfer by allowing the AP to fully utilize the entirety of a data frame.

The embodiments described herein improve the prior art by limiting overhead and improving the efficiency of data frame transmission. The time and frequency matrix <NUM> with a number of consecutive time windows, aligned in a time division multiplexing (TDM) fashion having specified time offsets. RUs <NUM>-<NUM> denote groups of bandwidth subcarriers (tones). The matrix has a height described by a plurality of RUs <NUM>-<NUM> and a width described by time. Although <FIG> denotes four RUs, the number of RUs within the matrix depends upon the bandwidth of the transmission signal. For example, there may be a maximum of <NUM> RUs for <NUM> bandwidth and <NUM> RUs for <NUM> bandwidth. Further divisions of bandwidth into RUs are defined in IEEE <NUM>. Thus the AP can schedule several consecutive transmit opportunities with a single trigger frame.

<FIG> illustrates an additional embodiment <NUM>. <FIG> incorporates the entirety of <FIG> along with a mechanism for re-transmission of any lost data. Data transmissions scheduled by matrix <NUM> may be lost due to many factors. It is desirable that deterministic traffic be able to overcome losses to provide reliability. Deterministic traffic does not mean that delivery has to be guaranteed, but that the delivery time should be known. The present embodiment addresses transmission loss by re-transmission of any lost data. A re-transmission <NUM> may also be known as an echo. The AP is aware of the deterministic schedules in the matrix <NUM> and the affordable amount of jitter. An additional transmission matrix <NUM> may be sent within the time set by acceptable jitter times. Therefore, additional triggers may be sent, to pull again the deterministic packets that were lost.

Re-transmission is accomplished by following the initial data frame with a second MU-RTS trigger <NUM> scheduling the transmission of additional data frames <NUM>. A block acknowledgement message informs that AP of any data packets requiring re-transmission. An additional CTS <NUM> may also be sent. The second MU-RTS trigger <NUM> schedules for transmission the data frames included within matrix <NUM>. The second matrix <NUM> may be sent with the same MU-RTS trigger <NUM> as the initial transmission or it may be sent with its own MU-RTS trigger <NUM>. For deterministic traffic, a trigger <NUM> is sent periodically at the granularity of the deterministic service, and the STAs response includes the top of queue packets and the RU size needed. Queued packets can be assigned to the matrix by priority with deterministic packets assigned the highest priority. The AP sorts the packets, assign the most important packets, and allocates RUs according to the needs of the packet assigned for re-transmission. Because the AP is aware of multiple deterministic schedules and the AP is aware of the amount of time for affordable jitter, the AP can pack more than one flow in one trigger. The second matrix <NUM> and any additional data frames <NUM> include previous traffic that was not received. When several retry matrices are sent in sequence (e.g., several echoes), each time there are less missing packets so the matrix can be shorter in time as illustrated in <FIG>. Any additional re-transmissions or data frames <NUM> include an MU-RTS trigger, CTS, and matrix as described herein.

The embodiments described herein illustrate the flexibility of the scheduling matrix included within the MU-RTS trigger. For example, the Data <NUM> and Data <NUM> for STA <NUM> require re-transmission. In the initial matrix, Data <NUM> for STA <NUM><NUM> was assigned transmission on RU <NUM>. In the re-transmission <NUM>, Data <NUM> for STA <NUM><NUM> can be assigned any RU that has a timeslot available for re-transmission. As depicted in <FIG>, rather than scheduling the transmission of Data <NUM> for STA <NUM> on RU <NUM>, the re-transmission is scheduled for RU <NUM>. Here, the AP is not constrained to re-schedule transmission on the same RU initially assigned to Data <NUM> for STA <NUM>. Instead the AP can use any available RU. In this way, the AP can maximize the data frames for re-transmission which efficiently packs data transmissions into available resources.

The second re-transmission <NUM> or additional data frames <NUM> can also be used opportunistically to schedule data frames for a first transmission. As illustrated in <FIG>, re-transmission <NUM> includes a first transmission for Data for STA <NUM>. Because the schedule for transmission is included in MU-RTS trigger <NUM>, an AP can assign any RU having an available timeslot.

Re-transmission efficiently allocates resources by decreasing the size of the corresponding matrix. For example, the time to transmit the data in matrix <NUM> is less than the amount of time to transmit in matrix <NUM>. By reducing the amount of time used to re-transmit additional data frames, re-transmissions <NUM> and data frames <NUM> consume less time and less resources. This permits re-transmission of any lost data within the amount of affordable jitter as well.

<FIG> illustrates an additional unclaimed embodiment. <FIG> uses the value "n" The value "n" indicates that there are a finite number of items but also that there are numerous items. The use of the value "n" is consistent with its application in mathematics to designate a large but finite number of items. For example, <FIG> designates a third AP as "<NUM>-n. " The use of "<NUM>-n" indicates that the number "n" includes a number of APs that can exceed three but is a defined number of numerous APs. APs <NUM>-<NUM> thru <NUM>-n and STAs <NUM>-<NUM> thru <NUM>-n form a wireless network <NUM>. Although three APs are depicted in <FIG>, any finite number of APs can be deployed in wireless network <NUM>. AP <NUM>-<NUM> communicates with STAs <NUM>-<NUM> thru <NUM>-<NUM>. Although five STAs are depicted as communicating with AP <NUM>-<NUM> any finite number of STAs can communicate each of the APs. An AP and its associated STAs can form a node in the larger wireless network <NUM>. APs <NUM>-<NUM> thru <NUM>-n schedule data transmissions from STAs <NUM>-<NUM> thru <NUM>-n as described in <FIG> and <FIG> and set forth herein. For example, AP <NUM>-<NUM> deploys the data transmission scheme set forth in <FIG>. AP <NUM>-<NUM> can schedule the plurality of transmit opportunities with an optional MU-RTS trigger <NUM>, an optional CTS message <NUM>, and a matrix <NUM>. The MU-RTS trigger <NUM> may be separated from the CTS message <NUM> by a short inter-frame space (SIFS) <NUM>. SIFS denote the amount of time in microseconds for a wireless interface to process a received frame. The CTS message <NUM> may also be separated from the matrix <NUM> by a second SIFS <NUM>. In the event that an transmissions are lost, APs <NUM>-<NUM> thru <NUM>-n and STAs <NUM>-<NUM> and <NUM>-n can re-transmit data as described with respect to <FIG> and as set forth herein.

<FIG> illustrates an additional unclaimed embodiment. APs <NUM>-<NUM> thru <NUM>-n and STAs <NUM>-<NUM> and <NUM>-n may also be part of a larger communication network <NUM>. APs <NUM>-<NUM> thru <NUM>-n and STAs <NUM>-<NUM> thru <NUM>-n form a wireless network <NUM>. An AP and its associated STAs can form a node in the larger wireless network. APs <NUM>-<NUM> thru <NUM>-n schedule data transmissions from STAs <NUM>-<NUM> thru <NUM>-n as described in <FIG> and <FIG> and set forth herein. Each of APs <NUM>-<NUM> thru <NUM>-n can communicate with networks <NUM> and <NUM>. For example, AP <NUM>-<NUM> communicates with network <NUM> through communication medium <NUM>. AP <NUM>-<NUM> can also communicate with network <NUM> through communication medium <NUM>. Similarly, AP <NUM>-n can communication with network <NUM> through communication medium <NUM> and can also communicate with network <NUM> through communication medium <NUM>. Finally, Networks <NUM> and <NUM> can communicate with each other through communication medium <NUM>. Networks <NUM> and <NUM> include the hardware and software necessary to form a network for data transmission. For example, networks <NUM> and <NUM> include hardware such as routers, switches, transmission lines, data centers, severs, and other hardware necessary to form a communication network. Networks <NUM> and <NUM> also include all necessary hardware for APs and STAs to connect to and communicate over the Internet. Communication mediums <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> can be either wireless or wired.

By increasing the flexibility and density of the data frames, eliminating overhead, and increasing the determinism of the data frames the embodiment described herein are an improvement over known systems and methods. These goals are reached by scheduling that uses a flexible scheduling matrix to provide complete information to an AP that explains who is sending what data and when that data will be sent.

<FIG> illustrates a method <NUM> of the device set forth in <FIG> and <FIG>. Method <NUM> includes the elements in <FIG> and <FIG>. At block <NUM> a trigger message <NUM> is transmitted to a plurality of STAs <NUM>-<NUM> thru <NUM>-n, the trigger message <NUM> includes a matrix <NUM> defining a plurality of RUs <NUM>-<NUM> that the plurality of STAs <NUM>-<NUM> thru <NUM>-n are assigned to transmit or receive data simultaneously for a fixed duration. At block <NUM>, the scheduled data is transmitted according to the matrix <NUM>. At block <NUM>, AP <NUM>-<NUM> receives an acknowledgement message indicating data packets scheduled but not received. At block <NUM>, AP <NUM>-<NUM> sends a second trigger message <NUM> and a second matrix <NUM> comprising timeslots and RUs for traffic not received by the STA.

In summary, techniques for managing communications between access points and stations (STAs) are described herein. An access point broadcasts a trigger message to a plurality of STAs, the trigger message includes a matrix defining a plurality of resource units (RUs) that the plurality of STAs are assigned to transmit or receive data. The matrix accomplishes time division multiplexing by assigning timeslots to a plurality of STAs. The matrix accomplishes frequency division multiplexing by also assigning frequency tones to the plurality of STAs.

These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the blocks of the flowchart illustrations and/or block diagrams.

Claim 1:
An access point, AP, comprising:
a transmitter configured to broadcast a trigger message to a plurality of stations, STAs, the trigger message comprising a matrix defining a plurality of resource units, RUs, that the plurality of STAs are assigned in order to transmit or receive data simultaneously for a fixed duration, the matrix further defining a first timeslot in a first RU of the plurality RUs that is assigned to a first STA of the plurality of STAs and a second timeslot in the first RU that is assigned to a second STA of the plurality of STAs,
and a receiver configured to receive data from the STAs using the RUs defined in the matrix.