Patent Description:
For example, the access point sends to an 11ax device (e.g., a device configured for <NUM> ax), a MU-EDCA Parameter Set information element in management frames including beacon, probe response, associate response, and re-associate response. This information element includes a new set of values of EDCA (e.g., Arbitration InterFrame Spacing Number (AIFSN), Exponent form of Minimum Contention Window (ECWmin), and Exponent form of Maximum Contention Window (ECWmax)) for each access category. Those values are more relaxed than the initial set passed in the EDCA Parameter Set element. The MU-EDCA Parameter Set information element also includes a timer value for how long these parameters take effect (e.g., MU-EDCA Timer).

The 11ax device participating in MU-OFDMA would have to wait for triggers from the access point and abide by a scheduling algorithm in the access point for transmitting uplink traffic (e.g., uplink data and control signals). However, a legacy device would contend more aggressively to obtain the channel and would get full access to the bandwidth of the channel for its transmission. This makes the 11ax device participating in MU-OFDMA more inferior to legacy devices in high-traffic load scenarios.

<CIT> discloses an electronic device that communicates frames with an access point (AP) by receiving, from the AP, a frame header that includes information specifying a first set of tones of an OFDMA communication, the first set of tones associated with first resource block subchannels having a first bandwidth used by the AP to transmit a frame payload. The electronic device obtains a second set of tones associated with second resource block subchannels having a second bandwidth that differs from the first bandwidth, and receives the frame payload using the OFDMA communication, the second resource block subchannels, and the second set of tones.

<CIT> discloses a communication method in a communication network comprising a plurality of nodes, at least one node comprising a plurality of traffic queues for serving data traffic at different priorities, each traffic queue being associated with a respective queue backoff value computed from respective queue contention parameters having first and second values in, respectively, a first and a second contention modes, obtaining quality of service requirements of data stored in a traffic queue of the node; checking whether the quality of service requirements can be fulfilled when accessing the communication channel using the second contention mode; if the requirements cannot be fulfilled as the result of the checking, disabling access to resource units provided by the other node within one or more transmission opportunities granted to the other node on the communication channel; and transmitting data stored in the traffic queue using the first contention mode.

<CIT> discloses an electronic device and a wireless communication method of an electronic device. The electronic device obtains information for mode switching when the electronic device is connected to an access point based on one of a first mode from among a multiple user multiple input multiple output (MU-MIMO) mode and a single user multiple input multiple output (SU-MIMO) mode; determining whether to switch the mode to a second mode, which is different from the first mode, from among the MU-MIMO mode and the SU-MIMO mode, based on the obtained information for mode switching; and performing wireless data communication with the access point based on the second mode when the electronic device is switched to the second mode.

<CIT> discloses methods, apparatuses and systems for using at least one sub-channel of a physical channel for uplink communication, the physical channel including a set of resources within first and second channel boundaries such that the physical channel includes a plurality of sub-channels, each sub-channel comprising a subset of the resources of the physical channel and having at least one sub-channel boundary which is not coincident with the first or the second channel boundaries, are provided.

This summary is provided to introduce simplified concepts of a switching scheme for opting in and out of multi-user orthogonal frequency-division multiple access (MU-OFDMA). In one example, an electronic device can opt out of an MU-OFDMA mode ("multi-user mode") when uplink traffic is high (e.g., above a threshold), which allows the electronic device to enter a single-user mode to maximize throughput by transmitting its uplink data without sharing channel bandwidth with other devices and without access restrictions mandated by the access point. In another example, the electronic device can opt out of the MU-OFDMA mode if low-latency requirements are critical, such as for an online gaming application, and if the access point is not responsive enough to meet those requirements. In yet another example, the electronic device can opt out of the MU-OFDMA mode based on Basic Service Set (BSS) metrics, such as if the electronic device estimates, based on a signal-strength measurement of a transmit channel, that the transmit channel can handle more data than the access point is allowing the electronic device to transmit under the multi-user mode. Opting out of the multi-user mode enables the electronic device to enter the single-user mode and contend for the transmit channel without any restrictions mandated by the access point.

The simplified concepts are further described below in the Detailed Description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining the scope of the claimed subject matter. The invention is defined by the independent claims; preferred embodiments are depicted in the dependent claims.

The details of one or more aspects of a switching scheme for opting in and out of MU-OFDMA are described below. The use of the same reference numbers in different instances in the description and the figures indicate similar elements:.

This document describes methods, devices, systems, and means for a switching scheme for opting in and out of multi-user orthogonal frequency-division multiple access (MU-OFDMA). Conventional techniques used to achieve high efficiency and utilization of MU-OFDMA cause 11ax electronic devices (e.g., devices configured for <NUM>. 11ax) participating in MU-OFDMA to be inferior to legacy devices in heavy-traffic load scenarios because the 11ax devices are forced to be less competitive in the medium contention window and wait for triggers sent by the access point(s). Techniques are described to balance between preserving high efficiency in low-traffic (non-critical latency) scenarios for overall Basic Service Set (BSS) efficiency and being as aggressive in contention when data load or latency requirements are critical. Thus, the techniques described herein are directed to a switching scheme for opting in and out of MU-OFDMA.

In one aspect, a method for opting in or out of an MU-OFDMA mode is disclosed, as in claim <NUM>.

In another aspect, an electronic device as in claim <NUM> is disclosed.

<FIG> illustrates an example environment <NUM>, which includes one or more electronic devices <NUM> and a Wi-Fi access point <NUM>. Each of these devices may be wireless-network-enabled and capable of communicating data, packets, and/or frames over a wireless link <NUM>. The wireless link <NUM> may include any suitable type of wireless communication link or wireless network connection. For example, the wireless link <NUM> may be implemented in whole or in part as a wireless local-area-network (WLAN), ad-hoc WLAN (e.g., a direct wireless link), wireless mesh network, near-field communication (NFC) link, wireless personal-area-network (WPAN), wireless wide-area-network (WWAN), or short-range wireless network. The wireless link <NUM> may be implemented in accordance with any suitable communication protocol or Institute of Electrical and Electronics Engineers (IEEE) standard, such as IEEE <NUM>-<NUM>, IEEE <NUM>-<NUM>, IEEE <NUM>. 11ac, IEEE <NUM>. 11ad, IEEE <NUM>. 11ah, IEEE <NUM>. 11ax, and the like. By using IEEE <NUM>. 11ax, the electronic device <NUM> can operate in radio bands between, and including, <NUM> and <NUM>, such as <NUM>, <NUM>, and <NUM> radio bands.

In this example, the access point <NUM> is implemented to provide and manage a wireless network that includes the wireless link <NUM>. The wireless links <NUM> may be implemented with any suitable modulation and coding scheme (MCS), such as orthogonal frequency division multiplexing access (OFDMA). In other cases, the access point <NUM> may include or be embodied as a host device, enhanced node base station, wireless router, broadband router, modem device, drone controller, vehicle-based network device, or other network administration node or device. Using IEEE <NUM>. 11ax, the access point <NUM> may provide multiple Wi-Fi networks, a <NUM> Wi-Fi network ("AP2G"), a <NUM> Wi-Fi network ("AP5G"), and/or a <NUM> Wi-Fi network ("AP6G"). The electronic device <NUM> may detect both Wi-Fi networks using a multi-user (MU) OFDMA mode. The electronic device may also have Multiple Input Multiple Output (MIMO) capabilities.

The electronic device(s) <NUM> operate as stations in the wireless network provided by the access point <NUM>. The electronic device <NUM> may include a smart-phone, set-top box, tablet computer, a wireless speaker, a wireless smart-speaker, a camera, a wearable device, a wireless printer, a mobile station, a laptop computer, a medical device, a security system, a drone, an Internet-of-Things (IoT) device, a gaming device, a smart appliance, an Internet-protocol enabled television (IP TV), a personal media device, a navigation device, a mobile-internet device (MID), a network-attached-storage (NAS) drive, a mobile gaming console, and so on.

Generally, the access point <NUM> provides connectivity to the Internet, other networks, or network-resources through a backhaul link (not shown), which may be either wired or wireless (e.g., a T1 line, fiber optic link, broadband cable network, intranet, a wireless-wide-area network). The backhaul link may include or connect with data networks operated by an internet service provider, such as a digital subscriber line or broadband cable provider, and may interface with the access point <NUM> via an appropriately configured modem (not shown). While associated with the wireless network provided by the access point <NUM> (e.g., via the wireless links <NUM>), the electronic device(s) <NUM> may access the Internet, exchange data with each other, or access other networks for which the access point <NUM> acts as a gateway.

<FIG> illustrates an example device diagram <NUM> of an access point and an electronic device in more detail. In aspects, the device diagram <NUM> describes devices that can implement various aspects of a switching scheme for opting in and out of MU-OFDMA. The electronic device(s) <NUM> operates as a station (STA) in the wireless network provided by the access point <NUM>. As a station, the electronic device <NUM> includes one or more antennas <NUM> and one or more transceivers <NUM> for communicating with the access point <NUM> or other wirelessly-enabled devices. The transceivers <NUM> may include any suitable number of respective communication paths (e.g., transmit or receive chains) to support transmission or reception of multiple spatial streams of data. Front-end circuitry (not shown) of the electronic device(s) <NUM> may couple or connect the transceiver <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> may include an array of multiple antennas that are configured similar to or differently from each other.

The electronic device(s) <NUM> also includes processor(s) <NUM> and memory <NUM> (computer-readable storage media <NUM>, CRM <NUM>). The processor(s) <NUM> may be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. The computer-readable storage media described herein excludes propagating signals. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the electronic device(s) <NUM>. The device data <NUM> includes user data, multimedia data, applications, and/or an operating system of the electronic device(s) <NUM> that are executable by processor(s) <NUM> to enable wireless communication and user interaction with the electronic device(s) <NUM>. In the context of the disclosure, the CRM <NUM> is implemented as storage media, and thus does not include transitory signals or carrier waves.

CRM <NUM> also includes an access-mode manager <NUM> (e.g., access-mode manager application <NUM>). Alternately or additionally, the access-mode manager <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the electronic device(s) <NUM>. In at least some aspects, the access-mode manager <NUM> configures the transceiver(s) <NUM> to implement the techniques described herein for a switching scheme for opting in and out of MU-OFDMA.

The access point <NUM> includes one or more antennas <NUM> and one or more transceivers <NUM> for communicating with the electronic device(s) <NUM> or other wirelessly-enabled devices. The transceivers <NUM> may include any suitable number of respective communication paths (e.g., transmit or receive chains) to support transmission or reception of multiple spatial streams of data. Front-end circuitry (not shown) of the access point <NUM> may couple or connect the transceiver <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> may include an array of multiple antennas that are configured similar to or different from each other.

The access point <NUM> also includes processor(s) <NUM> and memory <NUM> (computer-readable storage media <NUM>, CRM <NUM>). The processor(s) <NUM> may be a single-core processor or a multiple-core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. The computer-readable storage media described herein excludes propagating signals. CRM <NUM> may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the access point <NUM>. The device data <NUM> includes applications, and/or an operating system of the access point <NUM> that are executable by processor(s) <NUM> to enable wireless communication with the electronic device(s) <NUM>. In the context of the disclosure, the CRM <NUM> is implemented as storage media, and thus does not include transitory signals or carrier waves.

CRM <NUM> also includes an access point manager <NUM> (access point manager application <NUM>). Alternately or additionally, the access point manager <NUM> may be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the access point <NUM>. In at least some aspects, the access point manager <NUM> configures the transceiver(s) <NUM> to implement the techniques described herein for a switching scheme for opting in and out of MU-OFDMA. The access point manager <NUM> also configures a network interface <NUM> to relay communications between the electronic device(s) <NUM>, the access point <NUM>, and an external network.

Example methods <NUM>, <NUM>, and <NUM> are described with reference to <FIG>, respectively, in accordance with one or more aspects of a switching scheme for opting in and out of MU-OFDMA. The order in which the method blocks of methods <NUM>, <NUM>, and <NUM> are described is not intended to be construed as a limitation, and any number of the described method blocks can be skipped, repeated, or combined in any order to implement a method or an alternate method. Generally, any of the components, modules, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Some operations of the example methods may be described in the general context of executable instructions stored on computer-readable storage memory that is local and/or remote to a computer processing system, and implementations can include software applications, programs, functions, and the like. Alternatively or in addition, any of the functionality described herein can be performed, at least in part, by one or more hardware logic components, such as, and without limitation, Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SoCs), Complex Programmable Logic Devices (CPLDs), and the like.

<FIG> depicts an example method <NUM> for opting in and out of MU-OFDMA when uplink traffic is high. During periods of high uplink traffic, it may be more efficient for the electronic device <NUM> to opt out of MU-OFDMA rather than sharing the bandwidth of a transmit channel with other devices. At <NUM>, an electronic device enters an MU-OFDMA mode for communicating with an access point via a wireless network over a shared-channel bandwidth. For example, an electronic device (e.g., the electronic device <NUM>) transmits an Operation Mode Indication (OMI) to an access point (e.g., the access point <NUM>) to request initiation of the MU-OFDMA mode. The access point controls and synchronizes uplink transmissions of multiple electronic devices in the MU-OFDMA mode to enable simultaneous multiple-user transmissions to occur.

At <NUM>, the electronic device initiates a timer T1 (e.g., a first timer T1). The timer T1 may be any suitable timing mechanism and may be set to any suitable length of time, such as approximately <NUM> milliseconds (ms). The timer T1 is used to provide a minimum amount of time in which the electronic device <NUM> remains in the MU-OFDMA mode before switching to a different mode, such as the single-user mode.

At <NUM>, the electronic device <NUM> determines if an uplink (UL) queue size is greater than a first threshold size TH-<NUM> for the uplink queue. The uplink-queue size may provide an indication of high or low uplink traffic. An example threshold size may include a threshold size substantially equal to a size of a transmit channel, approximately two megabytes (MB) of data, or any other suitable size. In one implementation, the electronic device <NUM> uses the first threshold size TH-<NUM> to determine if the uplink data is sufficient to fill the entire transmit channel. If the channel can be filled by the uplink data, then no efficiency is lost by not sharing bandwidth of the transmit channel according to the multi-user mode.

If the uplink-queue size is not greater than the first threshold size TH-<NUM> (e.g., "NO" at <NUM>), then the electronic device <NUM> continues to monitor the size of the uplink queue. If the uplink-queue size is greater than the first threshold size TH-<NUM> ("YES" at <NUM>), then at <NUM> the electronic device determines if the timer T1 is expired. If the timer T1 is not yet expired ("NO" at <NUM>), then the electronic device <NUM> continues to monitor the uplink-queue size relative to the first threshold size TH-<NUM> at <NUM>. The timer T1 prevents the electronic device <NUM> from opting out of the MU-OFDMA mode too quickly after entering the MU-OFDMA mode.

If the timer T1 is expired ("YES" at <NUM>), then at <NUM> the electronic device <NUM> opts out of the MU-OFDMA mode. Opting out of the multi-user mode enables the electronic device <NUM> to not be limited to requirements of the access point under the multi-user mode. In an example, the electronic device <NUM> can send an OMI signal to the access point <NUM> to indicate that the electronic device is selecting to exit the MU-OFDMA mode and contend for the transmit channel in a single-user mode. In particular, the electronic device <NUM> can send a frame with an OM Control subfield having an uplink MU Disable subfield set to one (<NUM>), or having the uplink MU Disable subfield set to zero (<NUM>) and an uplink MU Data Disable subfield set to one (<NUM>). The electronic device <NUM> can receive an acknowledgment signal (e.g., ACK) from the access point <NUM> indicating that the MU-OFDMA mode is disabled for the electronic device <NUM>. When this frame is acknowledged by the access point, the electronic device can ignore the MU-OFDMA EDCA parameter set, which is mandated by the access point and may have relaxed values in comparison to standard EDCA parameters included in an initial EDCA parameter set information element used by the access point. The electronic device <NUM> may then apply the standard EDCA parameters included in the initial EDCA parameter set information element, which do not have relaxed values.

At <NUM>, the electronic device <NUM> enters the single user (SU) mode to contend for the transmit channel. The single-user mode enables the electronic device to contend for the transmit channel using different parameters than the parameters mandated by the access point as part of the multi-user mode, enabling the electronic device <NUM> to contend for the transmit channel as aggressively as a legacy device and/or the access point <NUM>.

At <NUM>, the electronic device <NUM> initiates a timer T2 (e.g., a second timer T2) in response to entering the single-user mode. The timer T2 may be set for any suitable duration of time, such as approximately <NUM>. The timer T2 may prevent the electronic device <NUM> from exiting the single-user mode too quickly, essentially ping-ponging back and forth between the multi-user mode and the single-user mode. Accordingly, the timer T2 provides a minimum amount of time for the electronic device <NUM> to operate in the single-user mode before it can attempt to re-enter the multi-user mode.

At <NUM>, the electronic device <NUM> determines if the uplink-queue size is below a second threshold size TH-<NUM>. An example of the second threshold size TH-<NUM> may include a threshold size substantially equal to half the size of a transmit channel, approximately one MB of data, or any other suitable size. The first threshold size TH-<NUM> and the second threshold size TH-<NUM> may be based on an access category (e.g., voice, video, best effort, and background access categories) of the uplink data, such that each threshold may differ for different access categories. For example, the first and second threshold sizes TH-<NUM> and TH-<NUM> can differ based on whether the uplink data is for Voice-over-Internet Protocol (VoIP), online gaming, audio data, video data, etc. In addition, in each access category, the first and second threshold sizes TH-<NUM> and TH-<NUM> can differ. An example implementation includes, for the voice access category, the first threshold size TH-<NUM> set to one kilobyte (KB) and the second threshold size TH-<NUM> set to <NUM> KB. In another implementation, for the video access category, the first threshold size TH-<NUM> may be set to <NUM> KB and the second threshold size TH-<NUM> may be set to <NUM> KB. An example implementation for the best effort and background access categories may include the first threshold size TH-<NUM> set to <NUM> MB and the second threshold size TH-<NUM> set to <NUM> MB. In another example, the first and second thresholds TH-<NUM> and TH-<NUM> may be dependent on the maximum latency in an uplink queue, such that each threshold may differ for different maximum latencies in uplink queues. Although several examples are described herein, any suitable threshold size may be used for the first and second threshold sizes TH-<NUM> and TH-<NUM>, and the sizes may depend on the implementation. These examples are not intended to be limiting.

If the uplink-queue size is equal to, or greater than, the second threshold size TH-<NUM> ("NO" at <NUM>), then the electronic device <NUM> remains in the single-user mode for transmitting uplink data. However, if the uplink-queue size drops below the second threshold size TH-<NUM>, then it is likely that the uplink traffic is sufficiently low to allow the multi-user mode to be more efficient for the electronic device <NUM> than the single-user mode. Accordingly, if the electronic device <NUM> determines that the uplink-queue size has decreased to a size that is less than the second threshold size TH-<NUM> ("YES" at <NUM>), then at <NUM>, the electronic device <NUM> determines if the timer T2 is expired, which indicates that a sufficient amount of time has passed since entering the single-user mode. Alternatively, the electronic device <NUM> can wait until the timer T2 expires before determining whether the uplink-queue size is equal to, or greater than, the second threshold size TH-<NUM>.

If the timer T2 is not expired ("NO" at <NUM>), then the electronic device <NUM> remains in the single-user mode for transmitting uplink data. Accordingly, the electronic device <NUM> delays opting back in to the MU-OFDMA mode until expiration of the timer T2. If the timer T2 is expired ("YES" at <NUM>), then it is determined that the electronic device <NUM> has spent a sufficient amount of time in the single-user mode, and the electronic device <NUM> may proceed to opt in to the multi-user mode.

Other forms of hysteresis can be implemented between the two threshold sizes TH-<NUM> and TH-<NUM> to reduce or prevent ping-ponging between the multi-user and single-user modes. For example, instead of using the timer T2 (or in addition to using the timer T2), the electronic device <NUM> can wait for the uplink-queue size to fall below the second threshold size TH-<NUM> by a predefined amount (e.g., value or percentage) before determining whether to opt in to the multi-user mode. A third threshold size can be used that is less than the second threshold size TH-<NUM> by the predefined amount. This additional condition may further reduce the likelihood of the electronic device <NUM> bouncing back and forth between single-user and multi-user modes.

At <NUM>, the electronic device <NUM> opts in to the MU-OFDMA mode. This can be achieved by the electronic device <NUM> transmitting an OMI signal, to the access point <NUM>, requesting to participate in the multi-user mode. The electronic device <NUM> receives an acknowledgment signal, from the access point <NUM>, providing permission and information to enter the multi-user mode. The electronic device <NUM> can then re-enter the MU-OFDMA mode at <NUM>.

<FIG> illustrates an example method <NUM> for opting out of MU-OFDMA to honor low-latency Quality-of-Service (QoS) requirements: this method, useful to understand the invention, does not fall within the scope of the claims. The method <NUM> may be performed by the electronic device <NUM> when implementing a low-latency application that requires quick access to uplink and downlink channels. At <NUM>, an electronic device (e.g., the electronic device <NUM>) connects to a wireless network using an MU-OFDMA mode.

At <NUM>, the electronic device <NUM> enters a low-latency mode for uplink traffic. The electronic device <NUM> may enter the low-latency mode when performing functions or executing an application having data load or latency requirements that are critical, such as online gaming.

At <NUM>, the electronic device <NUM> receives a plurality of triggers from an access point (e.g., the access point <NUM>). Triggers (e.g., trigger frames) are used by the access point <NUM> to schedule multi-user transmissions in both uplink and downlink directions. The access point <NUM> acts as a central coordinating entity and assigns time-frequency resource units (RUs) for reception or transmission to associated stations, which avoids RU contention overhead and increases efficiency in scenarios of dense deployments. For example, the access point <NUM> (Wifi AP) sends a downlink trigger frame to inform particular stations to send their data. The trigger frame includes information identifying a transmission interval, a bit rate of transmission, and a transmit power for the station (the electronic device(s) <NUM>) to use for the uplink transmission. The information in the trigger is defined in the <NUM>. 11ax specification.

At <NUM>, the electronic device <NUM> monitors a frequency at which the triggers are received from the access point <NUM>. In particular, the electronic device <NUM> monitors an average inter-arrival time of the triggers received from the access point <NUM>.

At <NUM>, the electronic device <NUM> determines if the frequency is greater than a threshold frequency TH-f. Any suitable threshold frequency TH-f can be used as a measure for an acceptable frequency for the triggers. In some aspects, the threshold frequency TH-f can be based on a type of application being used (e.g., VoIP application, online gaming application, etc.), a type of data (e.g., voice traffic, video data, audio data, etc.), or a particular access category of the uplink data. If the frequency is greater than the threshold frequency TH-f ("YES" at <NUM>), then the electronic device <NUM> maintains the MU-OFDMA mode and continues to monitor the frequency at <NUM>. The threshold frequency TH-f may represent a maximum queuing delay. When the frequency of the triggers is greater than the threshold frequency TH-f, then the triggers are being sent by the access point <NUM> fast enough to retain high efficiency in the multi-user mode.

If the frequency is less than the threshold frequency TH-f ("NO" at <NUM>), then at <NUM>, the electronic device <NUM> opts out of the MU-OFDMA mode. When the frequency of the triggers drops below the threshold frequency TH-f, the electronic device <NUM> can determine that, for some reason, the access point <NUM> is not responsive enough for the low-latency requirements. Delayed triggers result in more transmission delay. Accordingly, to improve efficiency, the electronic device <NUM> can select to opt out of the MU-OFDMA mode.

At <NUM>, the electronic device <NUM> enters a single-user mode to contend for a transmit channel on the wireless network without restrictions mandated by the access point. As above, the single-user mode (after opting out of the multi-user mode) enables the electronic device <NUM> to avoid scheduling and shared-channel bandwidth requirements set by the access point for the multi-user mode. Further, by opting out of the multi-user mode and switching to the single-user mode, the electronic device <NUM> avoids being penalized on latency, which would occur if the electronic device <NUM> did not opt out of the multi-user mode and simply used a relaxed set of contention parameters provided by the access point <NUM>.

In some scenarios, after entering the low-latency mode at <NUM>, the electronic device <NUM> may, at <NUM>, receive no triggers from the access point over a predefined duration of time, or may receive only a single trigger over the duration of time. In such scenarios, the method <NUM> proceeds directly from <NUM> to <NUM> to opt out of the MU-OFDMA mode.

As latency requirements are relaxed, or after a predefined period of time, the electronic device <NUM> can optionally, at <NUM>, opt back in to the MU-OFDMA mode. Then the method <NUM> may proceed to receiving triggers (at <NUM>), or not receiving triggers (at <NUM>), and monitoring (at <NUM>) the frequency at which the triggers are received from the access point <NUM>.

<FIG> illustrates an example method <NUM> for opting out of MU-OFDMA based on Basic Service Set (BSS) metrics: this method, useful to understand the invention, does not fall within the scope of the claims. At <NUM>, when connected to a wireless network using an MU-OFDMA mode, the electronic device <NUM> indicates to an access point of the wireless network uplink data to transmit.

At <NUM>, the electronic device <NUM> receives one or more triggers from the access point for transmitting the uplink data. In an example, the triggers include a mandated modulation and coding scheme (MCS) provided by the access point.

At <NUM>, the electronic device <NUM> performs a BSS clear channel assessment (CCA) of a transmit channel. A BSS CCA Busy is a Wi-Fi metric indicating how busy or clear the air time of a channel is. The electronic device <NUM> can monitor the channel busy time over a duration of time to obtain this metric. For example, the electronic device <NUM> listens for radio frequency (RF) transmissions at a physical layer of an air interface. The electronic device <NUM> uses a signal-detect threshold to identify a preamble transmission from another transmitting radio (e.g., the access point <NUM>) for synchronization between devices. In addition, the electronic device <NUM> uses an energy-detect threshold to detect other types of RF transmissions during the CCA.

At <NUM>, the electronic device <NUM> measures a received signal strength indicator (RSSI) of the transmit channel if the transmit channel is clear. This measurement provides an indication as to the quality of the signal on the transmit channel, which is in turn an indication of how fast the electronic device <NUM> can transmit data.

At <NUM>, the electronic device <NUM> estimates an MCS based on the measured RSSI. The estimated MCS indicates how many bits the electronic device <NUM> can transmit per symbol on the transmit channel.

At <NUM>, the electronic device <NUM> determines if a data rate associated the estimated MCS is greater than a data rate associated with the mandated MCS. In some aspects, the electronic device <NUM> can determine if the data rate associated with the estimated MCS is greater than the data rate associated with the mandated MCS by a threshold amount T. The MCS is an index to an array of rates, such that a higher MCS corresponds to a higher rate, and a lower MCS corresponds to a lower rate.

If the data rate associated with the estimated MCS is less than the data rate associated with the mandated MCS ("NO" at <NUM>), then at <NUM>, the electronic device <NUM> remains in the MU-OFDMA mode and transmits the uplink data using the MU-OFDMA mode according to the mandated MCS. In some aspects, the method <NUM> may proceed to <NUM> if the electronic device <NUM> determines that the data rate associated with the estimated MCS is greater than the data rate associated with the mandated MCS, but the difference between the data rates is less than the threshold amount T.

If the data rate associated with the estimated MCS is greater than the data rate associated with the mandated MCS ("YES" at <NUM>), then at <NUM>, the electronic device <NUM> opts out of the MU-OFDMA mode. Alternatively, the electronic device <NUM> opts out of the MU-OFDMA mode at <NUM> if the data rate associated with the estimated MCS is greater than the data rate associated with the mandated MCS by at least the threshold amount T.

At <NUM>, the electronic device <NUM> enters a single-user mode to contend for the transmit channel on the wireless network for transmission of the uplink data without restrictions mandated by the access point <NUM>.

Claim 1:
A method for opting in or out of a multi-user orthogonal frequency multiple access, MU-OFDMA, mode, the method comprising an electronic device:
entering the MU-OFDMA mode to communicate via a wireless network over a shared-channel bandwidth (<NUM>);
characterized by
responsive to entering the MU-OFDMA mode, initiating a timer (<NUM>);
during the MU-OFDMA mode, determining that an uplink-queue size is greater than a first threshold size (<NUM>) and that the timer has expired (<NUM>), the uplink queue comprising uplink data for transmission;
responsive to the determining:
opting out of the MU-OFDMA mode (<NUM>); and
entering a single-user mode to contend for a transmit channel for transmitting uplink data (<NUM>).