A switching scheme for opting in and out of multi-user OFDMA

Abstract

This document describes methods, devices, systems, and apparatus for selecting to enter and exit a switching scheme for multi-user orthogonal frequency division multiple access (MU-OFDMA). In one aspect, an electronic device (110) enters (302) a MU-OFDMA mode to communicate on a shared channel bandwidth via a wireless network (130). During the MU-OFDMA mode, the electronic device (110) determines (306) that an uplink queue size is greater than a first threshold size. In response to the determination, the electronic device (130) selects to exit (310) the MU-OFDMA mode and enters (312) a single-user mode to contend for a transmit channel for transmitting uplink data.

Description

Background Art

[0001] The Institute of Electrical and Electronics Engineers (IEEE) has developed a new standard called 802.11ax that improves Wi-Fi performance by implementing several schemes including Multi-User Orthogonal Frequency Division Multiple Access (MU-OFDMA). In MU-OFDMA, the channel bandwidth is shared among multiple users in both uplink and downlink transmissions. To achieve the target high efficiency, 802.11ax access points aim to maximize the time used by devices in MU-OFDMA relative to the time used by devices in single-user (SU) mode. This target high efficiency is achieved by the access point forcing devices to be less competitive in the medium contention window and by waiting for triggers sent by the access point using a more relaxed set of Enhanced Multimedia Distributed Control Access (EDCA) parameters relative to those used by the access point.

[0002] For example, an access point sends a MU-EDCA parameter set information element in a management frame including a beacon, a probe response, an association response, and a reassociation response to an 11ax device (e.g., a device configured for 802.11ax). The information element includes a new set of values ​​for EDCA (e.g., arbitration inter-frame space number (AIFSN), an exponential form of the minimum contention window (ECWmin), and an exponential form of the maximum contention window (ECWmax)) for each access category. These 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 (e.g., a MU-EDCA timer) for how long these parameters are in effect.

[0003] 11ax devices participating in MU-OFDMA will have to wait for a trigger from the access point and follow the scheduling algorithm in the access point for transmitting uplink traffic (e.g., uplink data and control signals). However, legacy devices will compete more aggressively to obtain the channel and will be given full access to the channel bandwidth for their transmissions. This makes 11ax devices participating in MU-OFDMA worse than legacy devices in high traffic load scenarios. Summary of the invention

[0004] The present invention content is provided to introduce a simplified concept of a switching scheme for selecting to join and exit multi-user orthogonal frequency division multiple access (MU-OFDMA). In one example, when the uplink traffic is high (e.g., above a threshold), the electronic device can choose to exit the MU-OFDMA mode ("multi-user mode"), which allows the electronic device to enter a single-user mode to maximize throughput by transmitting its uplink data without sharing the channel bandwidth with other devices and without access restrictions imposed by the access point. In another example, if low latency requirements are critical, such as for online gaming applications, and if the response of the access point is not sufficient to meet those requirements, the electronic device can choose to exit the MU-OFDMA mode. In another example, the electronic device can choose to exit the MU-OFDMA mode based on a basic service set (BSS) metric, such as if the electronic device estimates that the transmission channel can handle more data than the access point allows the electronic device to transmit in multi-user mode based on the signal strength measurement of the transmission channel. Selecting to exit the multi-user mode enables the electronic device to enter the single-user mode and compete for the transmission channel without any restrictions imposed by the access point.

[0005] The simplified concepts are further described in the following detailed description.This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used to determine the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The following describes details of one or more aspects of a switching scheme for selecting to join and exit MU-OFDMA. The same reference numerals are used in different instances in the specification and the drawings to indicate similar elements:

[0007] Figure 1 An example environment including one or more electronic devices and a Wi-Fi access point is shown.

[0008] Figure 2 An example device diagram showing an access point and an electronic device in greater detail.

[0009] Figure 3 Depicted is an example method for opting in and out of MU-OFDMA when uplink traffic is high.

[0010] Figure 4 An example method for opting out of MU-OFDMA to comply with low-latency quality of service (QoS) requirements is described.

[0011] Figure 5 Depicted are example methods for opting out of MU-OFDMA based on basic service set (BSS) metrics. DETAILED DESCRIPTION

[0012] Overview

[0013] This document describes methods, devices, systems, and apparatus for a switching scheme for opting in and out of Multi-User Orthogonal Frequency Division Multiple Access (MU-OFDMA). Conventional techniques for achieving high efficiency and utilization of MU-OFDMA cause 11ax electronic devices (e.g., devices configured for 802.11ax) participating in MU-OFDMA to perform worse than 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 (multiple) access points. Techniques are described for balancing between maintaining high efficiency in low traffic (non-critical latency) scenarios for overall basic service set (BSS) efficiency and being aggressive in contention when data load or latency requirements are critical. Therefore, the techniques described herein relate to a switching scheme for opting in and out of MU-OFDMA.

[0014] In one aspect, a method for selecting to join or exit MU-OFDMA mode is disclosed. The method includes an electronic device entering MU-OFDMA mode to communicate on a shared channel bandwidth via a wireless network. In addition, the method includes determining that an uplink queue size is greater than a first threshold size during MU-OFDMA mode. The method also includes selecting to exit MU-OFDMA mode and enter single-user mode in response to the determination to compete for a transmit channel for transmitting uplink data.

[0015] On the other hand, an electronic device is disclosed. The electronic device includes a memory and a processor system, the processor system being configured to execute instructions stored in the memory to implement an access mode manager application, the access mode manager application being configured to manage the transmission and reception of signals on a wireless network according to a MU-OFDMA mode. The access mode manager application is also configured to enter a low latency mode for uplink data transmission of an application. In addition, the access mode manager application is configured to monitor the frequency of triggers received from access points on the wireless network during the MU-OFDMA mode and the low latency mode of the electronic device to determine whether to continue using the MU-OFDMA mode or to opt out of the MU-OFDMA mode.

[0016] On the other hand, a method for opting out of MU-OFDMA mode is disclosed. The method is performed by an electronic device and includes indicating to an access point of the wireless network that the electronic device has uplink data to transmit when connected to the wireless network using MU-OFDMA mode. The method also includes receiving one or more triggers for transmitting uplink data from the access point, the one or more triggers including a mandatory modulation and coding scheme (MCS). In addition, the method includes performing a clear channel assessment (CCA) on a transmit channel, measuring the signal strength of the transmit channel, estimating the MCS based on the measured signal strength, and comparing a first data rate associated with the estimated MCS with a second data rate associated with the mandatory MCS to determine whether to opt out of MU-OFDMA mode.

[0017] Example Environment

[0018] Figure 1 An example environment 100 is shown that includes one or more electronic devices 110 and a Wi-Fi access point 120. Each of these devices can be wirelessly enabled and can communicate data, packets, and / or frames via a wireless link 130. The wireless link 130 can include any suitable type of wireless communication link or wireless network connection. For example, the wireless link 130 can be implemented in whole or in part as a wireless local area network (WLAN), an ad hoc WLAN (e.g., a direct wireless link), a wireless mesh network, a near field communication (NFC) link, a wireless personal area network (WPAN), a wireless wide area network (WWAN), or a short-range wireless network. The wireless link 130 can be implemented according to any suitable communication protocol or Institute of Electrical and Electronics Engineers (IEEE) standard (such as IEEE 802.11-2012, IEEE 802.11-2016, IEEE 802.11ac, IEEE 802.11ad, IEEE802.11ah, IEEE802.11ax, etc.). By using IEEE 802.11ax, the electronic device 110 may operate in radio frequency bands between 1 and 6 GHz and including, for example, 2.4 GHz, 5 GHz, and 6 GHz radio frequency bands.

[0019] In this example, access point 120 is implemented to provide and manage a wireless network including wireless link 130. Wireless link 130 can be implemented with any appropriate modulation and coding scheme (MCS), such as orthogonal frequency division multiple access (OFDMA). In other cases, access point 120 may include or be embodied as a host device, an enhanced node base station, a wireless router, a broadband router, a modem device, a drone controller, a vehicle-based network device, or other network management node or device. Using IEEE 802.11ax, access point 120 can provide multiple Wi-Fi networks, 2.4GHz Wi-Fi networks ("AP2G"), 5GHz Wi-Fi networks ("AP5G"), and / or 6GHz Wi-Fi networks ("AP6G"). Electronic device 110 can use multi-user (MU) OFDMA mode to detect two Wi-Fi networks. The electronic device may also have multiple-input multiple-output (MIMO) capabilities.

[0020] The electronic device(s) 110 operate as stations in a wireless network provided by the access point 120. The electronic devices 110 may include smartphones, set-top boxes, tablet computers, wireless speakers, wireless smart speakers, cameras, wearable devices, wireless printers, mobile stations, laptop computers, medical devices, security systems, drones, Internet of Things (IoT) devices, gaming devices, smart appliances, Internet Protocol enabled televisions (IP TVs), personal media devices, navigation devices, mobile Internet devices (MIDs), network attached storage (NAS) drives, mobile gaming consoles, and the like.

[0021] Typically, access point 120 provides connectivity to the Internet, other networks, or network resources via a backhaul link (not shown), which may be wired or wireless (e.g., a T1 line, a fiber optic link, a broadband cable network, an intranet, a wireless wide area network). The backhaul link may include or connect to a data network operated by an Internet service provider, such as a digital subscriber line or a broadband cable provider, and may interface with access point 120 via an appropriately configured modem (not shown). When associated with a wireless network provided by access point 120 (e.g., via wireless link 130), electronic device(s) 110 may access the Internet, exchange data with each other, or access other networks for which access point 120 acts as a gateway.

[0022] Example Device

[0023] Figure 2An example device diagram 200 of an access point and an electronic device is shown in more detail. In various aspects, the device diagram 200 describes devices that can implement various aspects of a switching scheme for opting in and out of MU-OFDMA. (Multiple) electronic devices 110 operate as stations (STAs) in a wireless network provided by an access point 120. As a station, the electronic device 110 includes one or more antennas 202 and one or more transceivers 204 for communicating with the access point 120 or other wireless-enabled devices. The transceiver 204 may include any appropriate number of corresponding communication paths (e.g., transmit chains or receive chains) to support the transmission or reception of multiple spatial data streams. The front-end circuitry (not shown) of the (multiple) electronic devices 110 may couple or connect the transceiver 204 to the antenna 202 to facilitate various types of wireless communications. The antenna 202 may include an array of multiple antennas configured to be similar or different from each other.

[0024] The (multiple) electronic devices 110 also include (multiple) processors 206 and memory 208 (computer readable storage medium 208, CRM 208). The (multiple) processors 206 can be single-core processors or multi-core processors composed of various materials (e.g., silicon, polysilicon, high-K dielectrics, copper, etc.). The computer-readable storage medium described herein does not include propagation signals. The CRM 208 may include any suitable memory or storage device that can be used to store device data 210 of the (multiple) electronic devices 110, such as random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory. The device data 210 includes user data, multimedia data, applications, and / or operating systems of the (multiple) electronic devices 110, which are executable by the (multiple) processors 206 to implement wireless communication and user interaction with the (multiple) electronic devices 110. In the context of the present disclosure, the CRM 208 is implemented as a storage medium and therefore does not include transient signals or carrier waves.

[0025] The CRM 208 also includes an access mode manager 212 (e.g., an access mode manager application 212). Alternatively or additionally, the access mode manager 212 can be implemented in whole or in part as hardware logic or circuitry that is integrated or separate from other components of the electronic device(s) 110. In at least some aspects, the access mode manager 212 configures the transceiver(s) 204 to implement the techniques described herein for selecting a switching scheme for joining and exiting MU-OFDMA.

[0026] The access point 120 includes one or more antennas 252 and one or more transceivers 254 for communicating with (multiple) electronic devices 110 or other wireless-enabled devices. The transceiver 254 may include any appropriate number of corresponding communication paths (e.g., transmit chains or receive chains) to support the transmission or reception of multiple spatial data streams. The front-end circuitry (not shown) of the access point 120 may couple or connect the transceiver 254 to the antenna 252 to facilitate various types of wireless communications. The antenna 252 may include an array of multiple antennas configured similarly or differently to each other.

[0027] The access point 120 also includes processor(s) 256 and memory 258 (computer readable storage medium 258, CRM 258). The processor(s) 256 may be a single-core processor or a multi-core processor constructed of various materials (e.g., silicon, polysilicon, high-K dielectrics, copper, etc.). The computer-readable storage media described herein do not include propagating signals. The CRM 258 may include any suitable memory or storage device that can be used to store device data 260 of the access point 120, such as a random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory. The device data 260 includes applications and / or an operating system of the access point 120, which is executable by the processor(s) 256 to implement wireless communication with the electronic device 110. In the context of the present disclosure, the CRM 258 is implemented as a storage medium and therefore does not include transient signals or carrier waves.

[0028] The CRM 258 also includes an access point manager 262 (access point manager application 262). Alternatively or additionally, the access point manager 262 can be implemented in whole or in part as hardware logic or circuitry that is integrated or separate from other components of the access point 120. In at least some aspects, the access point manager 262 configures the transceiver(s) 254 to implement the techniques described herein for selecting to join and exit the switching scheme for MU-OFDMA. The access point manager 262 also configures the network interface 264 to relay communications between the electronic device(s) 110, the access point 120, and an external network.

[0029] Example Method

[0030] References Figure 3-5Example methods 300, 400, and 500 according to one or more aspects of a switching scheme for selecting to join and exit MU-OFDMA are described. The order of the method boxes describing methods 300, 400, and 500 is not intended to be construed as limiting, and any number of the described method boxes may be skipped, repeated, or combined in any order to implement the method or replace the method. In general, any components, modules, methods, and operations described herein may be implemented using software, firmware, hardware (e.g., fixed logic circuits), manual processing, or any combination thereof. Some operations of the example methods may be described in the general context of executable instructions stored on a computer-readable storage memory locally and / or remotely of a computer processing system, and implementations may include software applications, programs, functions, and the like. Alternatively or additionally, any functions described herein may be performed at least in part by one or more hardware logic components, such as, but not limited to, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chip (SoCs), complex programmable logic devices (CPLDs), and the like.

[0031] Figure 3 An example method 300 for opting in and out of MU-OFDMA when uplink traffic is high is depicted. During periods of high uplink traffic, it may be more efficient for the electronic device 110 to opt out of MU-OFDMA rather than share the bandwidth of a transmit channel with other devices. At 302, the electronic device enters MU-OFDMA mode for communicating with an access point via a wireless network on a shared channel bandwidth. For example, an electronic device (e.g., electronic device 110) transmits an operation mode indication (OMI) to an access point (e.g., access point 120) to request the initiation of MU-OFDMA mode. The access point controls and synchronizes uplink transmissions of multiple electronic devices in MU-OFDMA mode to enable simultaneous multi-user transmissions to occur.

[0032] At 304, the electronic device starts 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 500 milliseconds (ms). The timer T1 is used to provide a minimum amount of time that the electronic device 110 remains in the MU-OFDMA mode before switching to a different mode (such as a single-user mode).

[0033] At 306, the electronic device 110 determines whether the uplink (UL) queue size is greater than a first threshold size TH-1 of the uplink queue. The uplink queue size may provide an indication of high or low uplink traffic. Example threshold sizes may include a threshold size substantially equal to the size of the transmission channel, approximately two megabytes (MB) of data, or any other suitable size. In one embodiment, the electronic device 110 uses the first threshold size TH-1 to determine whether the uplink data is sufficient to fill the entire transmission channel. If the channel can be filled with uplink data, efficiency is not lost due to not sharing the bandwidth of the transmission channel according to the multi-user mode.

[0034] If the uplink queue size is not greater than the first threshold size TH-1 (e.g., "No" at 306), the electronic device 110 continues to monitor the size of the uplink queue. If the uplink queue size is greater than the first threshold size TH-1 ("Yes" at 306), the electronic device determines whether the timer T1 has expired at 308. If the timer T1 has not expired ("No" at 308), the electronic device 110 continues to monitor the uplink queue size relative to the first threshold size TH-1 at 306. The timer T1 prevents the electronic device 110 from selecting to exit the MU-OFDMA mode too quickly after entering the MU-OFDMA mode.

[0035] If timer T1 expires ("Yes" at 308), then at 310, the electronic device 110 selects to exit the MU-OFDMA mode. Selecting to exit the multi-user mode enables the electronic device 110 to be unrestricted by the requirements of the access point in the multi-user mode. In an example, the electronic device 110 may send an OMI signal to the access point 120 to indicate that the electronic device is selecting to exit the MU-OFDMA mode and contend for a transmit channel in the single-user mode. Specifically, the electronic device 110 may send a frame having an OM control subfield having an uplink MU disable subfield set to one (1), or having an uplink MU disable subfield set to zero (0) and an uplink MU data disable subfield set to one (1). The electronic device 110 may receive an acknowledgment signal (e.g., ACK) from the access point 120 indicating that the MU-OFDMA mode is disabled for the electronic device 110. When the frame is acknowledged by the access point, the electronic device may ignore the MU-OFDMA EDCA parameter set, which is enforced by the access point and may have relaxed values ​​compared to the standard EDCA parameters included in the initial EDCA parameter set information element used by the access point. The electronic device 110 may then apply the standard EDCA parameters included in the initial EDCA parameter set information element that do not have relaxed values.

[0036] At 312, the electronic device 110 enters a single user (SU) mode to contend for a transmit channel. The single user mode enables the electronic device to contend for a transmit channel using parameters different from those imposed by the access point as part of the multi-user mode, thereby enabling the electronic device 110 to contend for a transmit channel as aggressively as legacy devices and / or access points 120.

[0037] At 314, the electronic device 110 starts a timer T2 (e.g., a second timer T2) in response to entering the single-user mode. The timer T2 can be set to any appropriate duration, such as approximately 500ms. The timer T2 can prevent the electronic device 110 from leaving the single-user mode too quickly, essentially ping-ponging between the multi-user mode and the single-user mode. Therefore, the timer T2 provides a minimum amount of time to operate in the single-user mode before the electronic device 110 can attempt to re-enter the multi-user mode.

[0038] At 316, the electronic device 110 determines whether the uplink queue size is lower than the second threshold size TH-2. Examples of the second threshold size TH-2 may include a threshold size substantially equal to half of the transmission channel size, about 1MB of data, or any other appropriate size. The first threshold size TH-1 and the second threshold size TH-2 may be based on the access category (e.g., voice, video, best effort, and background access category) of the uplink data, so that each threshold may be different for different access categories. For example, the first threshold size TH-1 and the second threshold size TH-2 may be different based on whether the uplink data is used for voice over Internet protocol (VoIP), online games, audio data, video data, etc. In addition, in each access category, the first threshold size TH-1 and the second threshold size TH-2 may be different. For the voice access category, an example implementation includes a first threshold size TH-1 set to 1 kilobyte (KB) and a second threshold size TH-2 set to 0.2KB. In another embodiment, for the video access category, the first threshold size TH-1 may be set to 10KB, and the second threshold size TH-2 may be set to 2KB. For best effort and background access categories, an example implementation may include a first threshold size TH-1 set to 2MB and a second threshold size TH-2 set to 1MB. In another example, the first threshold TH-1 and the second threshold TH-2 may depend on the maximum delay in the uplink queue, so that each threshold may be different due to different maximum delays in the uplink queue. Although several examples are described herein, any suitable threshold size may be used for the first threshold size TH-1 and the second threshold size TH-2, and the size may depend on the implementation. These examples are not intended to be limiting.

[0039] If the uplink queue size is equal to or greater than the second threshold size TH-2 ("No" at 316), the electronic device 110 remains in the single-user mode for transmitting uplink data. However, if the uplink queue size drops below the second threshold size TH-2, the uplink traffic may be low enough to allow the multi-user mode to be more efficient for the electronic device 110 than the single-user mode. Therefore, if the electronic device 110 determines that the uplink queue size has been reduced to a size less than the second threshold size TH-2 ("Yes" at 316), then at 318, the electronic device 110 determines whether the timer T2 has expired, which indicates that a sufficient amount of time has passed since entering the single-user mode. Alternatively, the electronic device 110 may wait until the timer T2 expires before determining whether the uplink queue size is equal to or greater than the second threshold size TH-2.

[0040] If the timer T2 has not expired ("No" at 318), the electronic device 110 remains in the single-user mode for transmitting uplink data. Therefore, the electronic device 110 delays selecting to return to the MU-OFDMA mode until the timer T2 expires. If the timer T2 expires ("Yes" at 318), it is determined that the electronic device 110 has spent a sufficient amount of time in the single-user mode, and the electronic device 110 can select to join the multi-user mode.

[0041] Other forms of hysteresis may be implemented between the two threshold sizes TH-1 and TH-2 to reduce or prevent a ping-pong effect between the multi-user mode and the single-user mode. For example, instead of using timer T2 (or in addition to using timer T2), the electronic device 110 may wait for the uplink queue size to drop below the second threshold size TH-2 by a predefined amount (e.g., a value or percentage) before determining whether to select to join the multi-user mode. A third threshold size that is smaller than the second threshold size TH-2 by a predefined amount may be used. Such additional conditions may further reduce the likelihood of the electronic device 110 bouncing back and forth between the single-user mode and the multi-user mode.

[0042] At 320, the electronic device 110 elects to join the MU-OFDMA mode. This may be accomplished by the electronic device 110 transmitting an OMI signal to the access point 120 to request participation in the multi-user mode. The electronic device 110 receives an acknowledgment signal from the access point 120 providing permission and information to enter the multi-user mode. The electronic device 110 may then re-enter the MU-OFDMA mode at 302.

[0043] Figure 4An example method 400 for opting out of MU-OFDMA to comply with low-latency quality of service (QoS) requirements is shown. The method 400 can be performed by the electronic device 110 when implementing a low-latency application that requires fast access to uplink and downlink channels. At 402, an electronic device (e.g., the electronic device 110) connects to a wireless network using MU-OFDMA mode.

[0044] At 404, the electronic device 110 enters a low latency mode for uplink traffic. The electronic device 110 may enter the low latency mode when performing a function or executing an application with critical data loading or latency requirements, such as an online game.

[0045] At 406, the electronic device 110 receives multiple triggers from an access point (e.g., access point 120). Access point 120 uses triggers (e.g., trigger frames) to schedule multi-user transmissions in the uplink and downlink directions. Access point 120 acts as a central coordination entity and assigns time-frequency resource units (RUs) for reception or transmission to associated stations, which avoids RU contention overhead and improves efficiency in dense deployment scenarios. For example, access point 120 (Wifi AP) sends a downlink trigger frame to notify specific stations to send their data. The trigger frame includes information identifying the transmission interval, the bit rate of the transmission, and the transmit power used by the station ((multiple) electronic devices 110) for uplink transmission. The information in the trigger is defined in the 802.11ax specification.

[0046] At 408, the electronic device 110 monitors the frequency of triggers received from the access point 120. Specifically, the electronic device 110 monitors the average inter-arrival time of the triggers received from the access point 120.

[0047] At 410, the electronic device 110 determines whether the frequency is greater than a threshold frequency TH-f. Any appropriate threshold frequency TH-f can be used as a measure of an acceptable frequency for triggering. In some aspects, the threshold frequency TH-f can be based on the type of application used (e.g., VoIP application, online gaming application, etc.), the type of data (e.g., voice service, video data, audio data, etc.), or a specific access category for uplink data. If the frequency is greater than the threshold frequency TH-f ("yes" at 410), the electronic device 110 maintains the MU-OFDMA mode and continues to monitor the frequency at 408. The threshold frequency TH-f can represent the maximum queuing delay. When the frequency of the trigger is greater than the threshold frequency TH-f, the access point 120 sends the trigger quickly enough to maintain high efficiency in multi-user mode.

[0048] If the frequency is less than the threshold frequency TH-f ("No" at 410), then at 412, the electronic device 110 chooses to exit the MU-OFDMA mode. When the frequency of the trigger drops below the threshold frequency TH-f, the electronic device 110 may determine that the access point 120 is not responding enough to the low latency requirement for some reason. The delayed triggering results in more transmission delays. Therefore, in order to improve efficiency, the electronic device 110 may choose to exit the MU-OFDMA mode.

[0049] At 414, the electronic device 110 enters the single-user mode to contend for a transmit channel on the wireless network without restrictions imposed by the access point. As described above, the single-user mode (after opting out of the multi-user mode) enables the electronic device 110 to avoid the scheduling and shared channel bandwidth requirements set by the access point for the multi-user mode. In addition, by opting out of the multi-user mode and switching to the single-user mode, the electronic device 110 avoids being penalized in latency, which would occur if the electronic device 110 did not opt ​​out of the multi-user mode and simply used a set of relaxed contention parameters provided by the access point 120.

[0050] In some scenarios, after entering the low latency mode at 404, the electronic device 110 may not receive a trigger from the access point within a predefined duration at 416, or may receive only a single trigger within the duration. In such scenarios, the method 400 proceeds directly from 416 to 412 to select to exit the MU-OFDMA mode.

[0051] As latency requirements are relaxed, or after a predefined period of time, the electronic device 110 may optionally choose to return to joining the MU-OFDMA mode at 418. The method 400 may then proceed to receiving a trigger (at 406), or not receiving a trigger (at 416), and monitoring (at 408) the frequency at which a trigger is received from the access point 120.

[0052] Figure 5 An example method 500 for opting out of MU-OFDMA based on basic service set (BSS) metrics is shown. At 502, the electronic device 110 indicates uplink data to be transmitted to an access point of the wireless network while connected to a wireless network using MU-OFDMA mode.

[0053] At 504, the electronic device 110 receives one or more triggers from the access point to transmit uplink data. In an example, the triggers include a mandatory modulation and coding scheme (MCS) provided by the access point.

[0054] At 506, the electronic device 110 performs a BSS Clear Channel Assessment (CCA) of the transmit channel. BSS CCA busy is a Wi-Fi metric that indicates how busy or idle the channel's air time is. The electronic device 110 can monitor the channel busy time over a duration to obtain the metric. For example, the electronic device 110 listens to radio frequency (RF) transmissions at the physical layer of the air interface. The electronic device 110 uses a signal detection threshold to identify a preamble transmission from another transmitting radio (e.g., access point 120) for synchronization between devices. In addition, the electronic device 110 uses an energy detection threshold to detect other types of RF transmissions during CCA.

[0055] At 508, if the transmit channel is idle, the electronic device 110 measures a received signal strength indicator (RSSI) of the transmit channel. This measurement provides an indication of the signal quality on the transmit channel, which in turn is an indication of how quickly the electronic device 110 can transmit data.

[0056] At 510, the electronic device 110 estimates an MCS based on the measured RSSI. The estimated MCS indicates how many bits per symbol the electronic device 110 can transmit on a transmission channel.

[0057] At 512, the electronic device 110 determines whether the data rate associated with the estimated MCS is greater than the data rate associated with the forced MCS. In some aspects, the electronic device 110 may determine whether the data rate associated with the estimated MCS is greater than the data rate associated with the forced MCS by a threshold amount T. The MCS is an index into an array of rates such that a higher MCS corresponds to a higher rate and a lower MCS corresponds to a lower rate.

[0058] If the data rate associated with the estimated MCS is less than the data rate associated with the forced MCS ("No" at 512), then at 514, the electronic device 110 remains in the MU-OFDMA mode and transmits uplink data using the MU-OFDMA mode according to the forced MCS. In some aspects, if the electronic device 110 determines that the data rate associated with the estimated MCS is greater than the data rate associated with the forced MCS but the difference between the data rates is less than the threshold amount T, the method 500 can proceed to 514.

[0059] If the data rate associated with the estimated MCS is greater than the data rate associated with the forced MCS ("YES" at 512), the electronic device 110 selects to exit the MU-OFDMA mode at 516. Alternatively, if the data rate associated with the estimated MCS is greater than the data rate associated with the forced MCS by at least a threshold amount T, the electronic device 110 selects to exit the MU-OFDMA mode at 516.

[0060] At 518 , the electronic device 110 enters a single user mode to contend for a transmit channel on the wireless network for transmitting uplink data without restrictions imposed by the access point 120 .

[0061] Here are some examples:

[0062] Example 1. A method for selecting to join or exit a multi-user orthogonal frequency multiple access (MU-OFDMA) mode, the method comprising an electronic device: entering the MU-OFDMA mode to communicate on a shared channel bandwidth via a wireless network; during the MU-OFDMA mode, determining that an uplink queue size is greater than a first threshold size; in response to the determination: selecting to exit the MU-OFDMA mode; and entering a single-user mode to compete for a transmission channel for transmitting uplink data.

[0063] Example 2. The method of Example 1, wherein the opting out comprises: transmitting an indication to disable the MU-OFDMA mode to an access point of the wireless network; and receiving a confirmation signal from the access point indicating that the MU-OFDMA mode is disabled for the electronic device.

[0064] Example 3. The method according to Example 1 or Example 2 further includes the electronic device: after entering the single-user mode, determining that the uplink queue size has been reduced to a size less than a second threshold size; and in response to determining that the uplink queue size has been reduced to a size less than the second threshold, selecting to join the MU-OFDMA mode.

[0065] Example 4. According to the method described in Example 3, selecting to enter the MU-OFDMA mode includes: transmitting a request to participate in the MU-OFDMA mode to an access point of the wireless network; receiving an additional confirmation signal for entering the MU-OFDMA mode; and re-entering the MU-OFDMA mode.

[0066] Example 5. The method according to Example 3 or Example 4 further includes: starting a timer in response to entering the single-user mode; and delaying selection to join the MU-OFDMA mode until the timer expires.

[0067] Example 6. The method of Example 3 or Example 4, further comprising: starting a timer in response to entering the single-user mode; and delaying the determination until after the timer expires.

[0068] Example 7. A method according to any one of Examples 3 to 6, wherein the determination includes determining that the uplink queue size has decreased below a third threshold size that is smaller than the second threshold size.

[0069] Example 8. A method according to any one of Examples 3 to 7, wherein the first threshold and the second threshold are based on an access category of the uplink data.

[0070] Example 9. A method according to any one of Examples 3 to 8, wherein at least one of the first threshold or the second threshold depends on a maximum delay in an uplink queue.

[0071] Example 10. The method of any of the preceding examples, further comprising: in response to entering the MU-OFDMA mode, starting a timer; and waiting until the timer expires before performing the determination.

[0072] Example 11. The method according to any of the preceding examples, further comprising: in response to entering the MU-OFDMA mode, starting a timer; and; delaying the exit selection until the timer expires.

[0073] Example 12. An electronic device comprising: a memory and a processor system, the processor system being configured to execute instructions stored in the memory to implement an access mode manager application, the access mode manager application being configured to manage the transmission and reception of signals on a wireless network according to a multi-user orthogonal frequency multiple access (MU-OFDMA) mode; entering a low latency mode for transmission of uplink data for an application; and during the MU-OFDMA mode and the low latency mode of the electronic device, monitoring a frequency of triggers received from an access point on the wireless network to determine whether to continue using the MU-OFDMA mode or to opt out (412) of the MU-OFDMA mode.

[0074] Example 13. An electronic device according to Example 12, wherein the access mode manager application is further configured to: determine that the frequency at which the trigger is received from the access point is greater than a threshold frequency; and based on the determination: maintain the electronic device in the MU-OFDMA mode; and continue to monitor the frequency at which the trigger is received from the access point.

[0075] Example 14. An electronic device according to Example 12 or Example 13, wherein the access mode manager application is further configured to: determine that the frequency of receiving the trigger from the access point is lower than a threshold frequency; in response to determining that the frequency is lower than the threshold frequency, exit the MU-OFDMA mode; and enter single-user mode to compete for a transmission channel for transmitting uplink data without restrictions imposed by the access point.

[0076] Example 15. An electronic device according to Example 14, wherein the determination is based on a maximum queuing delay.

[0077] Example 16. A method for exiting a multi-user orthogonal frequency multiple access (MU-OFDMA) mode, the method being performed by an electronic device: when connected to a wireless network using the MU-OFDMA mode, indicating to an access point of the wireless network that the electronic device has uplink data to transmit; receiving one or more triggers from the access point for transmitting the uplink data, the one or more triggers including a forced modulation and coding scheme (MCS); performing a clear channel assessment (CCA) of a transmit channel; measuring the signal strength of the transmit channel; estimating (MCS) based on the measured signal strength; and comparing a first data rate associated with the estimated MCS with a second data rate associated with the forced MCS to determine whether to exit the MU-OFDMA mode.

[0078] Example 17. The method according to Example 16 further includes: selecting to exit the MU-OFDMA mode based on the first data rate associated with the estimated MCS being greater than the second data rate associated with the forced MCS; and entering single-user mode to compete for the transmission channel for transmitting the uplink data without access restrictions imposed by the access point in the forced MCS.

[0079] Example 18. The method of Example 17, wherein the opting out is based on the first data rate associated with the estimated MCS being greater than the second data rate associated with the forced MCS by a threshold amount.

[0080] Example 19. The method of Example 17 or Example 18, wherein the opting out comprises transmitting an operation mode indication (OMI) to the access point to indicate that the electronic device opts out of participating in the MU-OFDMA mode with the access point.

[0081] Example 20. The method according to any one of Examples 16 to 19 further includes: determining that the first data rate associated with the estimated MCS is greater than the second data rate associated with the forced MCS; determining that the difference between the first data rate associated with the estimated MCS and the second data rate associated with the forced MCS is less than a threshold amount; and in response to the determination, transmitting the uplink data according to the MU-OFDMA mode and the forced MCS.

[0082] Example 21. An electronic device comprising: a memory and a processor system, which is configured to execute instructions stored in the memory to implement an access mode manager application, and the access mode manager application is configured to perform a method according to any one of Examples 1 to 11 and 16 to 20.

[0083] in conclusion

[0084] Although various aspects of a switching scheme for opting in and out of MU-OFDMA have been described in language specific to features and / or methods, the subject matter of the appended claims is not necessarily limited to the specific features or methods described. Rather, these specific features and methods are disclosed as example implementations of a switching scheme for opting in and out of MU-OFDMA, and other equivalent features and methods are intended to fall within the scope of the appended claims. In addition, various different aspects are described, and it should be understood that each aspect described may be implemented independently or in combination with one or more other described aspects.

Claims

1. A method for selecting to join or exit a multi-user orthogonal frequency division multiple access (MU-OFDMA) mode, the method being performed by an electronic device and comprising: Entering the MU-OFDMA mode to communicate on a shared channel bandwidth via a wireless network (302); responsive to entering the MU-OFDMA mode, starting a first timer defining an amount of time the electronic device is prevented from opting out of the MU-OFDMA mode; During the MU-OFDMA mode, determining that an uplink queue size is greater than a first threshold size (306); and In response to the determining and the expiration of the first timer: opting out of the MU-OFDMA mode (310); and A single user mode is entered to contend for a transmit channel for transmitting uplink data (312).

2. The method according to claim 1, wherein: Such opt-outs include: transmitting an indication to disable the MU-OFDMA mode to an access point of the wireless network; and An acknowledgement signal is received from the access point indicating that the MU-OFDMA mode is disabled for the electronic device.

3. The method according to claim 1, further comprising: after entering the single user mode, determining that the uplink queue size has decreased to a size less than a second threshold size; as well as Responsive to the determination that the uplink queue size has decreased to a size less than the second threshold, selecting to join the MU-OFDMA mode.

4. The method according to claim 3, wherein: Opting into the MU-OFDMA mode includes: transmitting a request to participate in the MU-OFDMA mode to an access point of the wireless network; receiving an additional confirmation signal for entering the MU-OFDMA mode; and Re-enter the MU-OFDMA mode.

5. The method according to claim 3, further comprising: starting a second timer in response to entering the single-user mode; as well as The selection to join the MU-OFDMA mode is delayed until the second timer expires.

6. The method according to claim 3, further comprising: starting a second timer in response to entering the single-user mode; as well as The determination that the uplink queue size is less than a second threshold size is delayed until after expiration of the second timer.

7. The method according to claim 3, wherein: The determination that the uplink queue size is less than a second threshold size includes determining that the uplink queue size has decreased below a third threshold size that is less than the second threshold size.

8. The method according to claim 3, wherein: The first threshold and the second threshold are based on an access category of the uplink data.

9. The method according to claim 3, wherein: At least one of the first threshold and the second threshold depends on a maximum delay in an uplink queue.

10. The method according to any one of claims 1 to 9, further comprising: Waiting until the first timer expires before performing the determination that the uplink queue size is greater than the first threshold size.

11. An electronic device, comprising: a memory and a processor, the processor being configured to execute instructions stored in the memory to implement an access mode manager application, the access mode manager application being configured to: Managing transmission and reception of signals on a wireless network according to a multi-user orthogonal frequency division multiple access MU-OFDMA mode; Entering the MU-OFDMA mode to communicate on a shared channel bandwidth via a wireless network; responsive to entering the MU-OFDMA mode, starting a first timer defining an amount of time the electronic device is prevented from opting out of the MU-OFDMA mode; During the MU-OFDMA mode, determining that an uplink queue size is greater than a first threshold size; In response to the determination that the uplink queue size is greater than the first threshold size and expiration of the first timer: Opting out of the MU-OFDMA mode; and Enter single user mode to contend for the transmit channel for transmitting uplink data.

12. The electronic device according to claim 11, wherein: To opt out of the MU-OFDMA mode, the access mode manager application is configured to: transmitting an indication to disable the MU-OFDMA mode to an access point of the wireless network; and An acknowledgement signal is received from the access point indicating that the MU-OFDMA mode is disabled for the electronic device.

13. The electronic device according to claim 11, wherein: The access mode manager application is further configured to: After entering the single user mode, determining that the uplink queue size has decreased to a size less than a second threshold size; and Responsive to the determination that the uplink queue size has decreased to a size less than the second threshold, selecting to join the MU-OFDMA mode.

14. The electronic device according to claim 13, wherein: To opt-in to the MU-OFDMA mode, the access mode manager application is configured to: transmitting a request to participate in the MU-OFDMA mode to an access point of the wireless network; receiving an additional confirmation signal for entering the MU-OFDMA mode; as well as Re-enter the MU-OFDMA mode.

15. The electronic device according to claim 13, wherein: The access mode manager application is further configured to: starting a second timer in response to entering the single-user mode; and The selection to join the MU-OFDMA mode is delayed until the second timer expires.

16. The electronic device according to claim 13, wherein: The access mode manager application is further configured to: starting a second timer in response to entering the single-user mode; and The determination that the uplink queue size has been reduced to a size less than a second threshold size is delayed until after expiration of the second timer.

17. The electronic device according to claim 13, wherein: Determining whether the uplink queue size has decreased to a size less than a second threshold size includes determining that the uplink queue size has decreased below a third threshold size that is less than the second threshold size.

18. The electronic device according to claim 13, wherein: The first threshold and the second threshold are based on an access category of the uplink data.

19. The electronic device according to claim 13, wherein: At least one of the first threshold and the second threshold depends on a maximum delay in an uplink queue.

20. The electronic device according to claim 11, wherein: The access mode manager application is further configured to wait until the first timer expires before making the determination that the uplink queue size is greater than the first threshold size.

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