Power control for Bluetooth low energy communication

Abstract

The present disclosure provides methods, components, devices, and systems for wireless communication. More specifically, some aspects relate to reducing the likelihood of flushing a protocol data unit (PDU) during Bluetooth Low Energy (BLE) audio communications between wireless communication devices. According to some aspects of the subject matter described in the present disclosure, a first wireless communication device may retransmit a PDU using a higher transmit power (e.g., a maximum transmit power of the first wireless communication device) in one or more sub-events (e.g., a final sub-event before a scour point) of the PDU, such as the first wireless communication device, in one or more sub-events (e.g., a final sub-event before the scour point). The probability that the second wireless communication device successfully receives the PDU before the PDU is scoured is increased. The subject matter described in the present disclosure may improve, among other benefits, the quality and reliability of BLE audio communications between wireless communication devices.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication, and more particularly, to power control for Bluetooth Low Energy (BLE) communication. Background Art

[0002] A wireless local area network (WLAN) can be formed by one or more wireless communication devices (e.g., an access point (AP) that provides a shared wireless communication medium for use by multiple client devices, which may also be referred to as stations (STAs)). The basic building block of a WLAN that complies with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards is a basic service set (BSS), which is managed by the AP. Each BSS is identified by a basic service set identifier (BSSID) advertised by the AP. The AP periodically broadcasts beacon frames so that any STA within the wireless range of the AP can establish or maintain a communication link with the WLAN.

[0003] Some WLANs can support low-energy communication between wireless communication devices. In some low-energy communication scenarios, packets that are not successfully received within a given time interval may be flushed (discarded), which can result in higher latency, reduced throughput, and greater signaling overhead. Summary of the Invention

[0004] The systems, methods, and devices of the present disclosure each have several innovative aspects, none of which alone is responsible for the desired attributes disclosed herein.

[0005] One innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication at a first wireless communication device. The method can include: establishing a communication link with at least one second wireless communication device, where the communication link is associated with low-energy audio communication between the first wireless communication device and the at least one second wireless communication device. The method can further include: transmitting one or more instances of a protocol data unit (PDU) to the at least one second wireless communication device via the communication link using a first transmit power, where the PDU is associated with a flush point. The method can further include: transmitting at least one instance of the PDU to the at least one second wireless communication device via the communication link using a second transmit power that is higher than the first transmit power, where the at least one instance of the PDU is transmitted during at least one sub-event that is directly before the flush point associated with the PDU.

[0006] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication at a first wireless communication device. The apparatus can include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions can be executed by the processor to cause the apparatus to perform the following operations: establish a communication link with at least one second wireless communication device, wherein the communication link is associated with low energy audio communication between the first wireless communication device and the at least one second wireless communication device. The instructions can also be executed by the processor to cause the apparatus to perform the following operations: transmit one or more instances of a PDU to the at least one second wireless communication device via the communication link using a first transmit power, wherein the PDU is associated with a flush point. The instructions can further be executable by the processor to cause the apparatus to perform the following operations: transmit at least one instance of the PDU to the at least one second wireless communication device via the communication link using a second transmit power that is higher than the first transmit power, wherein the at least one instance of the PDU is transmitted during at least one sub-event that is directly prior to the flush point associated with the PDU.

[0007] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication at a first wireless communication device. The apparatus can include: a unit for establishing a communication link with at least one second wireless communication device, wherein the communication link is associated with low energy audio communication between the first wireless communication device and the at least one second wireless communication device. The apparatus can further include: a unit for transmitting one or more instances of a PDU to the at least one second wireless communication device via the communication link using a first transmit power, wherein the PDU is associated with a flush point. The apparatus can further include: a unit for transmitting at least one instance of the PDU to the at least one second wireless communication device via the communication link using a second transmit power that is higher than the first transmit power, wherein the at least one instance of the PDU is transmitted during at least one sub-event that is directly prior to the flush point associated with the PDU.

[0008] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a non-transitory computer-readable medium storing code for wireless communication at a first wireless communication device. The code may include instructions executable by a processor to perform the following operations: establish a communication link with at least one second wireless communication device, wherein the communication link is associated with low-energy audio communication between the first wireless communication device and the at least one second wireless communication device. These instructions may also be executable by the processor to perform the following operations: transmit one or more instances of a PDU to the at least one second wireless communication device via the communication link using a first transmit power, wherein the PDU is associated with a flushing point. The instructions may also be executable by the processor to perform the following operations: transmit at least one instance of the PDU to the at least one second wireless communication device via the communication link using a second transmit power higher than the first transmit power, wherein the at least one instance of the PDU is transmitted during at least one sub-event directly preceding the flushing point associated with the PDU.

[0009] Some innovative aspects of the subject matter described in the present disclosure may also include: increasing the transmit power of the first wireless communication device from the first transmit power to the second transmit power during at least one sub-event based on a failure to receive an acknowledgment (ACK) message associated with one or more instances of a PDU transmitted using the first transmit power.

[0010] Some innovative aspects of the subject matter described in the present disclosure may also include: receiving, via the communication link, an ACK message associated with at least one instance of a PDU transmitted using the second transmit power from the at least one second wireless communication device.

[0011] Some innovative aspects of the subject matter described in the present disclosure may also include: reducing the transmit power of the first wireless communication device from the second transmit power to a third transmit power lower than the second transmit power based on receiving the ACK message.

[0012] Details of one or more implementations of the subject matter described in the present disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the specification, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of an example wireless local area network (WLAN) is shown.

[0014] Figure 2 An example protocol data unit (PDU) that may be used for communication between wireless communication devices is shown.

[0015] Figure 3 Shows an example signaling diagram supporting power control for Bluetooth Low Energy (BLE) communication.

[0016] Figure 4A and Figure 4B Shows an example communication timeline supporting power control for BLE communication.

[0017] Figure 5A and Figure 5B Shows an example communication timeline supporting power control for BLE communication.

[0018] Figure 6 Shows an example process flow supporting power control for BLE communication.

[0019] Figure 7 and Figure 8 Shows a flowchart illustrating an example process supporting power control for BLE communication.

[0020] Figure 9 Shows a block diagram of an example wireless communication device supporting power control for BLE communication.

[0021] Similar reference numerals and names in different figures indicate similar elements. Detailed Description

[0022] For purposes of describing the innovative aspects of the present disclosure, the following description relates to some specific examples. However, those of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. Some or all of the described examples can be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to one or more of the following: Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, IEEE 802.15 standards, Bluetooth as defined by the Bluetooth Special Interest Group (SIG), standards, or Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the Third Generation Partnership Project (3GPP), and other standards.

[0023] The described examples can be implemented in any device, system, or network capable of sending and receiving RF signals according to one or more of the following techniques or methods: Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single-Carrier FDMA (SC-FDMA), Space Division Multiple Access (SDMA), Rate-Split Multiple Access (RSMA), Multi-User Shared Access (MUSA), Single-User (SU) Multiple-Input Multiple-Output (MIMO), and Multi-User (MU)-MIMO. The described implementations can also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of the following: Wireless Personal Area Network (WPAN), Wireless Local Area Network (WLAN), Wireless Wide Area Network (WWAN), or Internet of Things (IoT) network.

[0024] Some wireless communication networks can support Bluetooth Low Energy (BLE) communication between wireless communication devices. BLE can support lower power operation and can be used across more than 40 channels in the 2.4 gigahertz (GHz) unlicensed Industrial, Scientific, and Medical (ISM) band. BLE can be used for various applications such as device location, indoor location services, and audio streaming. Compared to Bluetooth classic audio schemes such as Bluetooth Basic Rate (BR) and Enhanced Data Rate (EDR), the BLE audio scheme can provide improved performance and greater power savings. BLE audio data can be transmitted between wireless communication devices in the form of isochronous (ISO) packets, and each ISO packet can have an associated flush point. For example, if an ISO packet is not successfully received (which can also be referred to as a Protocol Data Unit (PDU)) (due to noise or interference), the wireless communication device can retransmit the ISO packet until the flush point is reached, at which point it may be flushed (discarded) from the audio stream. Flushed ISO packets can result in packet loss and noticeable audio glitches that negatively impact the user experience.

[0025] To reduce the likelihood and / or frequency of ISO packet flushing in BLE audio communication, a wireless communication device may use a higher transmit power (e.g., the maximum transmit power of the wireless communication device) to retransmit an ISO packet in one or more sub-events before the flushing point of the ISO packet (e.g., the final sub-event before the flushing point). For example, the wireless communication device may send an ISO packet using a first transmit power (e.g., a baseline or default transmit power) during an initial set of one or more sub-events, and if an acknowledgment (ACK) for the ISO packet has not been received, the wireless communication device may send the ISO packet using a second, larger transmit power during the last one or more sub-events that are directly before the flushing point of the ISO packet (where the number of the last one or more sub-events may be configurable or fixed). In some embodiments, after retransmitting the ISO packet using a higher transmit power during one or more sub-events that are directly before the flushing point of the ISO packet, the wireless communication device may use a lower transmit power (e.g., the first transmit power or another transmit power lower than the second transmit power) to send subsequent ISO packets. In some other embodiments, after retransmitting the ISO packet using a higher transmit power during one or more sub-events that are directly before the flushing point of the ISO packet, the wireless communication device may restart an evaluation timer and continue to use the higher transmit power until the evaluation timer has expired. Thereafter, the wireless communication device may evaluate and / or adjust the transmit power based on factors such as received signal strength indicator (RSSI) or negative acknowledgment (NACK) rate.

[0026] Certain aspects of the subject matter described in this disclosure may be implemented to realize one or more of the following potential advantages. Retransmitting an ISO packet using a higher transmit power in one or more sub-events (also referred to as transmission opportunities or transmission instances) before the flushing point of the ISO packet may improve the likelihood that the ISO packet is successfully received, thereby reducing the probability that the ISO packet is flushed. Thus, the techniques described herein may result in fewer discarded (flushed) ISO packets, improved BLE audio quality, and a better user experience (e.g., fewer glitches). For example, reducing the frequency and / or likelihood of ISO packet flushing may enable the wireless communication device to send and receive BLE communications with reduced latency, greater communication reliability (e.g., lower packet loss), and reduced signaling overhead. Additionally, the techniques described may enable the wireless communication device to more quickly adapt to dynamic, transient, or otherwise rapidly changing interference (e.g., interference that occurs in the middle of an evaluation interval). Thus, compared to other techniques, the techniques described may support relatively greater performance in relatively poor environments, which may further improve communication reliability.

[0027] Figure 1Shows a block diagram of an exemplary WLAN 100. According to some aspects, WLAN 100 can be an example of a Wi-Fi network. For example, WLAN 100 can be a network that implements at least one standard in the IEEE 802.11 wireless communication protocol standard series (such as the standards defined by the IEEE 802.11-2020 specification or its revisions, including but not limited to 802.11ay, 802.11ax, 802.11az, 802.11ba, 802.11bd, 802.11be, 802.11bf, and 802.11 revisions associated with Wi-Fi 8).

[0028] WLAN 100 can include many wireless communication devices, such as wireless access point (AP) 102 and multiple wireless stations (STA) 104. Although Figure 1 only one AP 102 is shown, WLAN 100 can also include multiple APs 102. Figure 1 The shown AP 102 can represent various different types of APs, including but not limited to enterprise-level APs, single-band APs, dual-band APs, independent APs, software-enabled APs (soft APs), and multi-link APs. The coverage area and capacity of cellular networks (such as LTE, 5G NR, etc.) can be further improved by small cells supported by APs used as small cell base stations. In addition, dedicated cellular networks can also be established through wireless local area networks using small cells.

[0029] Each of the STAs 104 can also be referred to as a mobile station (MS), mobile device, mobile phone, wireless phone, access terminal (AT), user equipment (UE), subscriber station (SS) or subscriber unit, and other examples. The STAs 104 can represent various devices, such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptop computers, Google notebooks, extended reality (XR) headsets, wearable devices, display devices (e.g., TVs (including smart TVs), computer monitors, navigation systems, etc.), music or other audio or stereo devices, remote control devices (“remote controls”), printers, kitchen appliances (including smart refrigerators) or other household appliances, key fobs (e.g., for keyless entry and start (PKES) systems), Internet of Things (IoT) devices, and vehicles, etc. Each STA 104 in the network can communicate with each other via the AP 102.

[0030] A single AP 102 and the associated set of STAs 104 can be called a basic service set (BSS), which is managed by the corresponding AP 102. Figure 1Also shown is an example coverage area 108 of the AP 102. The example coverage area 108 may represent the basic service area (BSA) of the WLAN 100. A BSS may be identified or indicated to a user by a service set identifier (SSID), and may be identified or indicated to other devices by a basic service set identifier (BSSID), which may be the media access control (MAC) address of the AP 102. The AP 102 may periodically broadcast beacon frames ("beacons") including the BSSID so that any STA 104 within the wireless range of the AP 102 can "associate" or re-associate with the AP 102 to establish a corresponding communication link 106 (also referred to hereinafter as a "Wi-Fi link") or maintain the communication link 106 with the AP 102. For example, the beacon may include an identification of the primary channel used by the corresponding AP 102, and a timing synchronization function for establishing or maintaining timing synchronization with the AP 102. The AP 102 may provide access to an external network to each STA 104 in the WLAN via the corresponding communication link 106.

[0031] To establish a communication link 106 with the AP 102, each STA 104 among the STAs 104 is configured to perform a passive or active scanning operation ("scanning") on a frequency channel in one or more frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, or 60 GHz bands). To perform passive scanning, the STA 104 listens for beacons transmitted by the corresponding AP 102 at a periodic time interval called the target beacon transmission time (TBTT) (measured in time units (TU), where one TU may be equal to 1024 microseconds (μs)). To perform active scanning, the STA 104 generates probe requests and sequentially transmits the probe requests on each channel to be scanned, and listens for probe responses from the AP 102. Each STA 104 may identify, determine, ascertain, or select the AP 102 with which to associate based on the scanning information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 106 with the selected AP 102. The AP 102 assigns an association identifier (AID) to the STA 104 at the culmination of the association operation, and the AP 102 uses the AID to track the STA 104.

[0032] As a result of the increasing popularity of wireless networks, STA 104 may have the opportunity to select one of many BSSs within the range of the STA, or to select among multiple APs 102 that together form an extended service set (ESS) including multiple connected BSSs. Extended network stations associated with the WLAN 100 can be connected to a wired or wireless distribution system that can allow multiple APs 102 to be connected in such an ESS. Accordingly, STA 104 can be covered by more than one AP 102, and can be associated with different APs 102 at different times for different transmissions. Additionally, after associating with an AP 102, STA 104 can also periodically scan its surrounding environment to find a more suitable AP 102 to associate with. For example, a STA 104 that is moving relative to its associated AP 102 can perform a "roaming" scan to find another AP 102 with more desirable network characteristics (such as a larger received signal strength indicator (RSSI) or reduced traffic load).

[0033] In some cases, STA 104 can form a network without an AP 102 or other devices other than the STA 104 itself. An example of such a network is an ad hoc network (or wireless ad hoc network). An ad hoc network can alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, an ad hoc network can be implemented within a larger wireless network (such as the WLAN 100). In such an example, although STA 104 may be able to communicate with each other through the AP 102 using the communication link 106, STA 104 can also communicate directly with each other via a direct wireless communication link 110. Additionally, two STAs 104 can communicate via the direct communication link 110 regardless of whether both STAs 104 are associated with the same AP 102 and served by the same AP 102. In such an ad hoc system, one or more of the STAs 104 can assume the role that the AP 102 plays in the BSS. Such a STA 104 can be referred to as a group owner (GO), and can coordinate transmissions within the ad hoc network. Examples of the direct wireless communication link 110 include Wi-Fi direct connection, a connection established by using a Wi-Fi tunnel direct link setup (TDLS) link, and other P2P group connections.

[0034] AP 102 and STA 104 can operate and communicate according to one or more of the IEEE 802.11 wireless communication protocol standards (via the respective communication link 106). These standards define the WLAN radio and baseband protocols for the PHY layer and the MAC layer. AP 102 and STA 104 send and receive wireless communications (hereinafter also referred to as "Wi-Fi communications" or "wireless packets") with each other in the form of PHY PDUs (PPDUs). The AP 102 and STA 104 in the WLAN 100 can send PPDUs on an unlicensed spectrum, which can be a part of the spectrum including the frequency bands traditionally used by Wi-Fi technologies (such as the 2.4 GHz band, 5 GHz band, 60 GHz band, 3.6 GHz band, and 900 MHz band). Some examples of the AP 102 and STA 104 described herein can also communicate in other frequency bands (such as the 5.9 GHz and 6 GHz bands), which can support both licensed and unlicensed communications. AP 102 and STA 104 can also communicate on other frequency bands such as shared licensed bands, where multiple operators can have licenses to operate in the same or overlapping frequency bands or frequency ranges.

[0035] Each of the frequency bands can include multiple sub-bands or frequency channels. For example, PPDUs compliant with the IEEE 802.11n, 802.11ac, 802.11ax, and 802.11be standard revisions can be sent on the 2.4, 5 GHz, or 6 GHz bands, with each of the frequency bands divided into multiple 20 MHz channels. Accordingly, these PPDUs are sent on physical channels with a minimum bandwidth of 20 MHz, but larger channels can be formed by channel bonding. For example, PPUDs can be sent on physical channels with a bandwidth of 40 MHz, 80 MHz, 160, or 320 MHz by bonding multiple 20 MHz channels together.

[0036] Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PHY service data unit (PSDU). The information provided in the preamble can be used by a receiving device to decode the subsequent data in the PSDU. In instances where a PPDU is transmitted over a bonded channel, the preamble field can be replicated and transmitted in each of the multiple component channels. The PHY preamble can include both a legacy portion (or “legacy preamble”) and a non-legacy portion (or “non-legacy preamble”). The legacy preamble can be used for packet detection, automatic gain control, and channel estimation, among other uses. The legacy preamble can also generally be used to maintain compatibility with legacy devices. The format of the information provided in the non-legacy portion of the preamble, the encoding of the information, and the information are associated with a particular IEEE 802.11 protocol used to transmit the payload.

[0037] Retransmission protocols such as Hybrid Automatic Repeat reQuest (HARQ) can also provide performance gains. HARQ protocols can support various HARQ signaling between transmitting and receiving wireless communication devices, as well as signaling between the PHY and MAC layers to improve retransmission operations in a WLAN. HARQ uses a combination of error detection and error correction. For example, a HARQ transmission can include error check bits that are added to data to be transmitted using an error detection (ED) code such as a Cyclic Redundancy Check (CRC). A receiving device can use the error check bits to determine whether it has correctly decoded the received HARQ transmission. In some examples, the original data (information bits) to be transmitted can be encoded with a Forward Error Correction (FEC) code, such as a Low Density Parity Check (LDPC) coding scheme that systematically encodes the information bits to produce parity check bits. The transmitting device can send both the original information bits and the parity check bits to the receiving device in a HARQ transmission. The receiving device can be able to use the parity check bits to correct errors in the information bits, thus avoiding retransmission.

[0038] Implementing a Hybrid Automatic Repeat reQuest (HARQ) protocol in a Wireless Local Area Network (WLAN) can improve the reliability of data transmitted from a transmitting device to a receiving device. The HARQ protocol can support the establishment of a HARQ session between two devices. Once a HARQ session is established, if the receiving device is unable to correctly decode (and correct errors in) a first HARQ transmission received from the transmitting device, the receiving device can send a HARQ feedback message (e.g., a Negative Acknowledgment (NACK) indicating that at least a portion of the first HARQ transmission was not correctly decoded) to the transmitting device. Such a HARQ feedback message can be different from a traditional block ACK feedback message type associated with traditional Automatic Repeat reQuest (ARQ). In response to receiving the HARQ feedback message, the transmitting device can send a second HARQ transmission to the receiving device to convey additional assistance in decoding at least a portion of the first HARQ transmission. For example, the transmitting device can include some or all of the original information bits, some or all of the original parity bits, and other different parity bits in the second HARQ transmission. The combined HARQ transmissions can be processed for decoding and error correction such that a complete signal associated with the HARQ transmissions can be obtained.

[0039] In some examples, the receiving device can be enabled to control whether to continue the HARQ process or revert to a non-HARQ retransmission scheme (e.g., an ARQ protocol). Such switching can reduce feedback overhead and increase the flexibility of retransmissions by allowing the device to dynamically switch between ARQ and HARQ protocols during frame exchanges. Some implementations can also allow multiplexing of communications using ARQ and communications using HARQ.

[0040] According to an example implementation described herein, a first wireless communication device (e.g., a central device, which can be AP102 or STA 104) can send a PDU to at least one second wireless communication device (e.g., at least one peripheral device, which can be an example of a connected device or a Bluetooth device, such as earbuds, headphones, speakers, etc.), and if the likelihood of successfully receiving the PDU at the at least one second wireless communication device becomes lower (e.g., becomes less than a threshold likelihood, which can be measured or assumed based on the number of remaining sub-events until the flush point of the PDU), a variable transmit power technique can be employed to dynamically adjust the transmit power. For example, the first wireless communication device can use a first transmit power for a first set of one or more instances of the PDU, and if the first wireless communication device fails to receive an ACK for the PDU before the last X sub-events immediately preceding the flush point of the PDU, the transmit power can be increased from the first transmit power to a second transmit power. In an example where the first wireless communication device fails to receive the ACK, the first wireless communication device can use the second transmit power to send one or more instances of the PDU during the X sub-events immediately preceding the flush point of the PDU. As described herein, X can be any number including 1, 2, 3, etc., and can be fixed or configurable.

[0041] Figure 2 FIG. 200 shows an example PDU 200 that can be used for wireless communication between a wireless AP 102 and one or more STAs 104. For example, PDU 200 can be configured as a PPDU. As shown, PDU 200 includes a PHY preamble 202 and a PHY payload 204. For example, preamble 202 can include a legacy portion, which itself includes a legacy short training field (L-STF) 206 that can consist of two symbols, a legacy long training field (L-LTF) 208 that can consist of two symbols, and a legacy signal field (L-SIG) 210 that can consist of two symbols. The legacy portion of preamble 202 can be configured according to the IEEE 802.11a wireless communication protocol standard. Preamble 202 can also include a non-legacy portion that includes one or more non-legacy fields 212, e.g., compliant with one or more standards in the IEEE 802.11 wireless communication protocol standard family.

[0042] The L-STF 206 generally enables a receiving device to perform coarse timing and frequency tracking and automatic gain control (AGC). The L-LTF 208 generally enables a receiving device to perform fine timing and frequency tracking and also perform an initial estimation of the wireless channel. The L-SIG 210 generally enables a receiving device to determine (e.g., obtain, select, identify, detect, ascertain, calculate, or compute) the duration of a PDU and use the determined duration to avoid transmitting on top of the PDU. The conventional portion of the preamble (including the L-STF 206, L-LTF 208, and L-SIG 210) may be modulated according to a binary phase shift keying (BPSK) modulation scheme. The payload 204 may be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another suitable modulation scheme. The payload 204 may include a PSDU that includes a data field (DATA) 214, which in turn may carry higher layer data, for example, in the form of a MAC PDU (MPDU) or an aggregated MPDU (A-MPDU).

[0043] According to an example embodiment described herein, a first wireless communication device (e.g., a central device) may transmit a PDU 200 to at least one second wireless communication device (e.g., at least one peripheral device) and may dynamically adjust the transmit power using a variable transmit power technique if the likelihood of successfully receiving the PDU 200 at the at least one second wireless communication device becomes low (e.g., becomes less than a threshold likelihood, which may be measured or assumed based on the number of remaining sub-events until the flush point of the PDU 200). For example, the first wireless communication device may use a first transmit power for a first set of one or more instances of the PDU 200 and may increase the transmit power from the first transmit power to a second transmit power if the first wireless communication device fails to receive an ACK for the PDU 200 before the last X sub-events immediately preceding the flush point of the PDU 200. In an example where the first wireless communication device fails to receive the ACK, the first wireless communication device may use the second transmit power to transmit one or more instances of the PDU 200 during the X sub-events immediately preceding the flush point of the PDU 200. As described herein, X may be any number including 1, 2, 3, etc. and may be fixed or configurable.

[0044] Figure 3 An example signaling diagram 300 supporting power control for BLE communication is shown. The signaling diagram 300 includes a wireless communication device 305 and one or more wireless communication devices 310, each of which may be referred to Figure 1An example of one of the described AP102 or STA 104. Signaling diagram 300 also includes ISO packets 315-a and ISO packets 315-b, each of which can be an example of the PDU 200 described with reference to Figure 2 In the example described in Figure 3 , if the previous transmission of ISO packet 315-a is not successfully received by one or more wireless communication devices 310, the wireless communication device 305 can retransmit ISO packet 315-a using a higher transmit power.

[0045] As described with reference to Figure 1 and Figure 2 , a wireless communication network (such as WLAN 100) can support BLE audio communication between the wireless communication device 305 and one or more wireless communication devices 310. In some embodiments, the wireless communication device 305 can be an example of a central (master) wireless communication device, and one or more wireless communication devices 310 can be examples of remote (peripheral) wireless communication devices. The wireless communication device 305 can transmit BLE audio data to one or more wireless communication devices 310 in the form of ISO packets (equivalently referred to as PDUs herein).

[0046] The wireless communication device 305 can use a first transmit power (such as the transmit power 525 described with reference to Figure 5A and Figure 5B ) to send ISO packet 315-a to one or more wireless communication devices 310. If the wireless communication device 305 does not receive an ACK 320 for ISO packet 315-a (e.g., if ISO packet 315-a is not successfully received by one or more wireless communication devices 310), the wireless communication device 305 can retransmit ISO packet 315-a (e.g., using the first transmit power) until the flush point of ISO packet 315-a is reached. If the wireless communication device 305 does not receive an ACK for ISO packet 315-a before the flush point, the wireless communication device 305 can discard or flush ISO packet 315-a and start sending ISO packet 315-b (the next ISO packet).

[0047] According to one or more aspects of the subject matter described in the present disclosure, the wireless communication device 305 can improve the likelihood that one or more wireless communication devices 310 successfully receive ISO packet 315-a by increasing the transmit power of ISO packet 315-a in one or more sub-events before the flush point of ISO packet 315-a. For example, the wireless communication device 305 can perform in the final sub-event before the flush point of ISO packet 315-a (such as the reference Figure 4AIn the described sub-event 420-a), the transmission power of ISO packet 315-a is increased from a first transmission power to a second transmission power (such as the maximum transmission power of wireless communication device 305).

[0048] In some embodiments, wireless communication device 305 may return to using a lower transmission power (such as the first transmission power) after the flush point of ISO packet 315-a. In other embodiments, wireless communication device 305 may continue to use the second transmission power for the remainder of the current evaluation interval (such as the evaluation interval 520 described with reference to Figure 5A and Figure 5B ). For example, wireless communication device 305 may use the second transmission power to transmit one or more instances of ISO packet 315-b (a subsequent ISO packet). Additionally or alternatively, wireless communication device 305 may restart an evaluation timer (which defines the length or duration of the evaluation interval) after increasing the transmission power of ISO packet 315-a, and may use the second transmission power until the evaluation timer has expired.

[0049] At the end of the current evaluation interval, wireless communication device 305 may evaluate and in some examples adjust the transmission power for a subsequent evaluation interval. Wireless communication device 305 may perform this evaluation based on various factors, including (but not limited to) RSSI, SNR, or NACK rate associated with communication between wireless communication device 305 and one or more wireless communication devices 310. Adjusting the transmission power may improve the likelihood that one or more wireless communication devices 310 successfully receive ISO packet 315 from wireless communication device 305 in a subsequent evaluation interval.

[0050] Figure 4A and Figure 4B Example communication timelines 400 and 401 that support power control for BLE communication are shown. Communication timeline 400 and communication timeline 401 may each be implemented by a wireless communication device (such as wireless communication device 305 described with reference to Figure 3 or one of AP 102 or STA 104 described with reference to Figure 1 ). In the Figure 4A example, if a previous transmission of a first ISO packet was not successfully received, the wireless communication device may retransmit the first ISO packet (denoted as #1) using the same transmission power. In the Figure 4B example, the wireless communication device may use a higher transmission power to retransmit the first ISO packet in at least one sub-event immediately before the flush point 410 of the first ISO packet.

[0051] As described herein, some wireless communication networks (such as WLAN 100) may support BLE audio communication between wireless communication devices. Maintaining the quality of BLE audio communication can positively contribute to the overall user experience. BLE audio data may be transmitted via ISO packets (equivalently referred to as PDUs herein). Each ISO packet may have an associated flush point (such as flush point 410). After reaching the flush point of an ISO packet, the ISO packet may be flushed even if the intended recipient (such as a remote or peripheral device) does not successfully receive the ISO packet. Flushed ISO packets may result in latency, packet loss, and noticeable audio glitches that negatively impact the user experience.

[0052] According to some aspects of the subject matter described in this disclosure, a wireless communication device (such as the wireless communication device 305 described with reference to Figure 3 can reduce the likelihood that an ISO packet is not successfully received and flushed by increasing the transmission power of the ISO packet just before the flush point of the ISO packet. For example, if transient interference 405 occurs in the middle of an evaluation interval (such as the evaluation interval 520 described with reference to Figure 5A and Figure 5B ), the wireless communication device can adjust the transmission power of the ISO packet in real time to mitigate the transient interference 405. In some embodiments, the wireless communication device may also adjust the transmission power per evaluation interval based on factors such as the NACK rate or RSSI for BLE audio.

[0053] In Figure 4A 's example, due to transient interference 405, a second wireless communication device (such as a remote device) may not be able to receive and decode a first ISO packet (denoted as #1) from a first wireless communication device (such as a central device). If the first wireless communication device does not receive an ACK from the second wireless communication device within a specified time frame, the first wireless communication device may determine that the first ISO packet was not successfully delivered and may retransmit the first ISO packet one or more times (e.g., using the same transmission power). If the first wireless communication device does not receive an ACK for the first ISO packet before the flush point 410, the first wireless communication device may flush the first ISO packet and start sending a second ISO packet (denoted as #2). Similarly, if the first wireless communication device does not receive an ACK for the second ISO packet before the flush point 415 of the second ISO packet, the first wireless communication device may flush the second ISO packet and continue with the next ISO packet.

[0054] In Figure 4BIn the example, the first wireless communication device may continue to retransmit the first ISO packet until sub-event 420-a (e.g., the last sub-event before the flush point 410 of the first ISO packet), at which point the first wireless communication device may increase the transmit power of the first ISO packet. Retransmitting the first ISO packet using a higher transmit power in sub-event 420-a can help mitigate the negative impact of the instantaneous interference 405 and can increase the likelihood that the second wireless communication device successfully receives the first ISO packet.

[0055] For example, if the second wireless communication device successfully receives the first ISO packet during sub-event 420-a, the second wireless communication device may send an ACK to the first wireless communication device. Accordingly, the first wireless communication device may start sending the second ISO packet to the second wireless communication device. If the first wireless communication device fails to receive an ACK for the second ISO packet before sub-event 420-b (the final sub-event before the flush point 415 of the second ISO packet), the first wireless communication device may increase the transmit power of the second ISO packet to improve the likelihood that the second wireless communication device successfully receives the second ISO packet. Increasing the probability of successful ISO packet reception (and thereby reducing the probability of ISO packet flushing) can improve the quality and overall performance of BLE communication.

[0056] Figure 5A and Figure 5B illustrate example communication timelines 500 and 501 that support power control for BLE communication. Communication timeline 500 and communication timeline 501 may each be implemented by a wireless communication device (such as the wireless communication device 305 described with reference to Figure 3 or one of the AP 102 or STA 104 described with reference to Figure 1 ). In the example of Figure 5A , if a previous transmission of the first ISO packet was not successfully received, the wireless communication device may retransmit the first ISO packet (denoted as #1) using the same transmit power. In the example of Figure 5B , the wireless communication device may use a higher transmit power to retransmit the first ISO packet in at least one sub-event immediately preceding the flush point 510 of the first ISO packet.

[0057] In some aspects of the subject matter described in this disclosure, a wireless communication device (e.g., wireless communication device 605) may use a higher transmit power (e.g., the maximum transmit power of the wireless communication device) for ISO packets having an upcoming flush point. The techniques described herein may support improved BLE audio quality as well as reduced power consumption, and may be applicable to various BLE audio links and devices that support BLE audio communication. Additionally, the techniques described may provide performance gains in communication environments having lower signal quality (e.g., environments having a relatively high interference level).

[0058] In Figure 5A the example of, due to instantaneous interference 505, a second wireless communication device (such as a remote device) may not be able to receive and decode a first ISO packet (denoted as #1) from a first wireless communication device (such as a central device). If the first wireless communication device does not receive an ACK from the second wireless communication device within a specified time frame, the first wireless communication device may determine that the first ISO packet was not successfully delivered, and may retransmit the first ISO packet one or more times (e.g., using transmit power 525). If the first wireless communication device does not receive an ACK for the first ISO packet before the flush point 510, the first wireless communication device may flush the first ISO packet and start transmitting a second ISO packet (denoted as #2). Similarly, if the first wireless communication device does not receive an ACK for the second ISO packet before the flush point 515 of the second ISO packet, the first wireless communication device may flush the second ISO packet and proceed to the next ISO packet.

[0059] In some embodiments, the first wireless communication device may make one or more transmit power adjustments at the end of an evaluation interval 520 (e.g., to account for noise, interference, and other factors that occurred or changed during the evaluation interval 520). For example, the first wireless communication device may determine to use a higher transmit power (such as transmit power 530) in a subsequent evaluation interval based on the RSSI, SNR, or NACK rate associated with the evaluation interval 520. In other words, an evaluation interval (such as evaluation interval 520) may be associated with a baseline or default transmit power that may be adjusted from a baseline or default transmit power of a previous evaluation interval (e.g., based on the RSSI, SNR, or NACK rate of the previous evaluation interval). The length of the evaluation interval may be defined by an evaluation timer having a configurable duration, which may (in some cases) be equal to 100 milliseconds.

[0060] In Figure 5BIn the example of, the first wireless communication device may continue to retransmit the first ISO packet (if the previous transmission was not successfully received) until the last sub-event before the flush point 510 of the first ISO packet, at which point the first wireless communication device may switch from the transmit power 525 (lower transmit power) to the transmit power 530 (higher or maximum transmit power). Increasing the transmit power of the first ISO packet just before the flush point 510 may increase the probability that the second wireless communication device successfully receives the first ISO packet before it is flushed.

[0061] In some implementations, the first wireless communication device may restart the evaluation timer after increasing the transmit power of the first ISO packet and may continue to use the transmit power 530 until the evaluation timer has expired (e.g., until the next evaluation interval). Thus, the first wireless communication device may use the transmit power 530 to transmit the second ISO packet (denoted as #2), the third ISO packet (denoted as #3), and the fourth ISO packet (denoted as #4) during sub-events within the evaluation interval 535 (the length of which may correspond to the duration of the restarted evaluation timer). Using the transmit power 530 for the remainder of the evaluation interval 535 may help mitigate the instantaneous interference 505 and may increase the likelihood that the second wireless communication device successfully receives (and acknowledges) subsequent transmissions from the first wireless communication device. Thus, according to the techniques described, the default or baseline transmit power for the evaluation interval 535 may be the transmit power 530.

[0062] Figure 6 An example process flow 600 that supports power control for BLE communication is shown. The process flow 600 includes a wireless communication device 605 (e.g., the first wireless communication device), which may be an example of one or more aspects of the wireless communication device 305 referred to Figure 3 described. The process flow 600 also includes at least one wireless communication device 610 (e.g., the second wireless communication device), which may be an example of one or more of the wireless communication devices 310 referred to Figure 3 described. In the following description of the process flow 600, the operations between the wireless communication device 605 and the at least one wireless communication device 610 may be added, omitted, or performed in a different order (relative to the example order shown).

[0063] At 615, the wireless communication device 605 may establish a communication link with the at least one wireless communication device 610. In some examples, the wireless communication device 605 may use the communication link (which may be a reference Figure 1Exchange BLE communications with at least one wireless communication device 610 using, for example, one of the described communication links 106 or 110. For example, the wireless communication device 605 may use the communication link to configure or otherwise establish a connectionless ISO stream (CIS) between the wireless communication device 605 and at least one wireless communication device 610.

[0064] At 620, the wireless communication device 605 may transmit one or more instances of a PDU (e.g., reference PDU 200 and / or reference ISO packet 315-a as described) to at least one wireless communication device 610 via the communication link using a first transmit power (e.g., reference transmit power 525 as described). The PDU may be associated with a flush point (such as flush point 410 as described with reference to Figure 5A and Figure 5B ), after which the wireless communication device 605 may discard (flush) the PDU. Figure 2 described) and / or reference Figure 3 described ISO packet 315-a). The PDU may be associated with a flush point (such as flush point 410 as described with reference to Figure 4A and Figure 4B ), after which the wireless communication device 605 may discard (flush) the PDU.

[0065] In some embodiments, at 625, the wireless communication device 605 may increase the transmit power of the PDU from the first transmit power to a second transmit power that is higher than the first transmit power (e.g., reference transmit power 530 as described with reference to Figure 5A and Figure 5B ). The wireless communication device 605 may increase the transmit power of the PDU based on a failure to receive an ACK (such as ACK 320 as described with reference to Figure 3 ) for the PDU from at least one wireless communication device 610. The wireless communication device 605 may also increase the transmit power of the PDU based on other factors (such as the instantaneous interference level, RSSI, or SNR associated with the communication link between the wireless communication device 605 and at least one wireless communication device 610).

[0066] At 630, the wireless communication device 605 may transmit at least one instance of the PDU to at least one wireless communication device via the communication link using the second transmit power, which may correspond to the maximum transmit power of the wireless communication device 605. As described herein, the wireless communication device 605 may perform at least one sub-event (such as reference Figure 4A and Figure 4BTransmit at least one instance of a PDU during the described sub - event 420 - a). The at least one sub - event can include: the last sub - event before the flush point associated with the PDU, the last two sub - events before the flush point associated with the PDU, or the last three sub - events before the flush point associated with the PDU, and so on. The number of the at least one sub - event can be fixed (e.g., via a network specification) or configurable (e.g., via signaling). In some embodiments, the wireless communication device 605 and another device (e.g., AP 102 or at least one wireless communication device 610) can exchange signaling that indicates or otherwise configures the number of the at least one sub - event. In some examples, the at least one sub - event can be part of a larger CIS event within an ISO interval.

[0067] After transmitting at least one instance of a PDU using a second transmit power, the wireless communication device 605 can (in some embodiments) restart an evaluation timer and continue to use the second transmit power until the evaluation timer has expired. In some examples, the wireless communication device 605 can receive an ACK for the PDU at 635. The wireless communication device 605 can receive the ACK via a communication link from at least one wireless communication device 610. At 640, the wireless communication device 605 can optionally reduce the transmit power for subsequent communication with at least one wireless communication device 610 when the ACK is received or after a certain amount of the ISO interval has elapsed relative to the reception of the ACK. This number of ISO intervals between the reception of the ACK and the reduction of the transmit power (e.g., from the second transmit power) can be fixed (e.g., via a network specification) or configurable (e.g., via signaling). In some embodiments, the wireless communication device 605 and another device (e.g., AP 102 or at least one wireless communication device 610) can exchange signaling that indicates or otherwise configures the number of ISO intervals between the reception of the ACK and the reduction of the transmit power.

[0068] Figure 7 A flowchart illustrating an example process 700 executable by a wireless communication device that supports power control for BLE communication in accordance with some aspects of the present disclosure is shown. The operations of process 700 can be implemented by a wireless communication device or its components. For example, process 700 can be performed by the wireless communication device 305 described as operating as a wireless STA or wireless AP or operating within a wireless STA or wireless AP. In some examples, process 700 can be performed by a wireless STA (such as one of the STAs 104 described) or a wireless AP (such as one of the APs 102 described). Figure 3 described as operating as a wireless STA or wireless AP or operating within a wireless STA or wireless AP. Figure 1 described as one of the STAs 104 Figure 1 described as one of the APs 102

[0069] At 705, a first wireless communication device may establish a communication link with at least one second wireless communication device, where the communication link is associated with low energy audio communication between the first wireless communication device and the at least one second wireless communication device.

[0070] At 710, the first wireless communication device may transmit one or more instances of a PDU to the at least one second wireless communication device via the communication link using a first transmit power, where the PDU is associated with a flush point.

[0071] At 715, the first wireless communication device may transmit at least one instance of a PDU to the at least one second wireless communication device via the communication link using a second transmit power that is higher than the first transmit power, where the at least one instance of the PDU is transmitted during at least one sub - event that is directly before the flush point associated with the PDU.

[0072] Figure 8 A flowchart illustrating an example process 800 that may be performed at a wireless communication device supporting power control for BLE communication in accordance with some aspects of the present disclosure is shown. Operations of process 800 may be implemented by a wireless communication device or components thereof. For example, process 800 may be performed by one of the wireless communication devices 310 operating as or within a wireless STA as described with reference to Figure 3 In some examples, process 800 may be performed by a wireless STA (such as one of the STAs 104 described with reference to Figure 1 ).

[0073] At 805, a second wireless communication device may establish a communication link with the first wireless communication device, where the communication link is associated with low energy audio communication between the first wireless device and the second wireless device.

[0074] At 810, a second wireless communication device may receive at least one instance of a PDU from a first wireless communication device via a communication link during at least one sub-event that is directly before a flush point associated with the PDU. In some embodiments, the second wireless communication device may receive at least one instance of the PDU having a higher signal strength during at least one sub-event that is directly before the flush point of the PDU, based on a failure to successfully receive one or more previous instances of the PDU. In other words, if an initial set of transmission attempts of the PDU fails to be successfully received, the first wireless communication device and the second wireless communication device may support techniques for dynamically increasing the transmit power for the PDU. Accordingly, the second wireless communication device may monitor one or more previous instances of the PDU during one or more sub-events and may receive at least one instance of the PDU having a relatively higher signal strength (e.g., a relatively higher RSSI value) compared to the one or more previous instances of the PDU during at least one sub-event that is directly before the flush point of the PDU.

[0075] At 815, the second wireless communication device may send an ACK message via the communication link to the first wireless device, associated with at least one instance of the PDU received during at least one sub-event.

[0076] Figure 9 A block diagram of an example wireless communication device 900 that supports power control for BLE communication in accordance with some aspects of the present disclosure is shown. In some examples, the wireless communication device 900 may be configured or operable to perform process 700 described with reference to Figure 7 or process 800 described with reference to Figure 8 or both. In various examples, the wireless communication device 900 may be a chip, an SoC, a chipset, a package, or a device that includes: one or more modems (such as a Wi-Fi (IEEE 802.11) modem or a cellular modem, such as a modem compliant with 3GPP 4G LTE or 5G), one or more processors, processing blocks, or processing elements (collectively referred to as "processors"); one or more radio units (collectively referred to as "radio units"); and one or more memories or memory blocks (collectively referred to as "memory").

[0077] In some examples, the wireless communication device 900 may be for use in a STA or an AP (such as with reference to Figure 1The device used in the described STA104 or AP 102). In some other examples, the wireless communication device 900 can be a STA or AP that includes such a chip, SoC, chipset, package, or device, as well as multiple antennas. The wireless communication device 900 is capable of sending and receiving wireless communications in the form of, for example, wireless packets. For example, the wireless communication device can be configured or operable to send and receive packets in the form of physical layer PPDUs and MPDUs that conform to one or more standards in the IEEE802.11 wireless communication protocol standard series.

[0078] In some examples, the wireless communication device 900 further includes an application processor or can be coupled to an application processor, and the application processor can be further coupled to another memory. In some examples, the wireless communication device 900 further includes a user interface (UI) (such as a touch screen or a keyboard) and a display, and the display can be integrated with the UI to form a touch screen display. In some examples, the wireless communication device 900 can further include one or more sensors, such as one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors.

[0079] The wireless communication device 900 includes a communication link component 902, a PDU component 904, a transmit power component 906, an ACK component 908, an evaluation timer component 910, and a BLE audio component 912. Portions of one or more components of the wireless communication device 900 can be implemented at least partially in hardware or firmware. For example, the PDU component 904 can be implemented at least partially by a modem. In some examples, at least some of the components 902, 904, 906, 908, 910, and 912 of the wireless communication device 900 are implemented at least partially by a processor and are implemented as software stored in a memory. For example, portions of one or more of the components 902, 904, 906, 908, 910, and 912 of the wireless communication device 900 can be implemented as non-transitory instructions (or "code") executable by a processor to perform the functions or operations of the corresponding modules.

[0080] In some embodiments, the processor can be a component of a processing system. A processing system generally refers to a set of systems or a series of machines or components that receive inputs and process the inputs to produce outputs (the set of outputs can be passed to other systems or components of, for example, device 900). For example, the processing system of device 900 can refer to a system that includes various other components or sub-components of device 900, such as a processor, or a transceiver, or a communication manager, or a combination of other components or components of device 900. The processing system of device 900 can interface with other components of device 900 and can process information (such as inputs or signals) received from other components, or output information to other components.

[0081] For example, the chip or modem of device 900 may include a processing system, a first interface for outputting information, and a second interface for obtaining information. In some implementations, the first interface may refer to the interface between the processing system of the chip or modem and the transmitter, such that device 900 can send the information output from the chip or modem. In some implementations, the second interface may refer to the interface between the processing system of the chip or modem and the receiver, such that device 900 can obtain information or signal input, and the information can be passed to the processing system. Those of ordinary skill in the art will readily recognize that the first interface can also obtain information or signal input, and the second interface can also output information or signal output.

[0082] The communication link component 902 may be capable of, configured to, or operable to establish a communication link with at least one second wireless communication device, where the communication link is associated with low-energy audio communication between wireless communication device 900 and at least one second wireless communication device.

[0083] The PDU component 904 may be capable of, configured to, or operable to output one or more instances of a PDU using a first transmit power for transmission via the communication link to at least one second wireless communication device, where the PDU is associated with a flush point.

[0084] The PDU component 904 may also be capable of, configured to, or operable to output at least one instance of a PDU using a second transmit power higher than the first transmit power for transmission via the communication link to at least one second wireless communication device, where at least one instance of the PDU is sent during at least one sub-event that is directly before the flush point associated with the PDU. In some examples, the at least one sub-event includes a single last sub-event before the flush point associated with the PDU. In some other examples, the at least one sub-event is part of a CIS event within an ISO interval.

[0085] The transmit power component 906 may be capable of, configured to, or operable to increase the transmit power of wireless communication device 900 from the first transmit power to the second transmit power during at least one sub-event based on a failure to receive an ACK message associated with one or more instances of a PDU sent using the first transmit power.

[0086] The ACK component 908 may be capable of, configured to, or operable to receive, via the communication link, an ACK message associated with at least one instance of a PDU sent using the second transmit power from at least one second wireless communication device. In some examples, the second transmit power corresponds to the maximum transmit power of wireless communication device 900.

[0087] In some examples, the transmit power component 906 may be capable of, configured to, or operable to reduce the transmit power of the wireless communication device 900 from a second transmit power to a third transmit power that is lower than the second transmit power based on receiving an ACK message. In some examples, the transmit power component 906 may reduce the transmit power of the wireless communication device 900 from the second transmit power to the third transmit power after a certain amount of ISO interval has elapsed relative to the receipt of the ACK message associated with at least one instance of the PDU.

[0088] In some examples, the transmit power component 906 may be capable of, configured to, or operable to increase the transmit power of the wireless communication device 900 from a first transmit power to a second transmit power during at least one sub-event based on an instantaneous interference level associated with a communication link between the wireless communication device 900 and at least one second wireless communication device.

[0089] The evaluation timer component 910 may be capable of, configured to, or operable to restart a timer associated with an evaluation interval based on increasing the transmit power of the wireless communication device 900 from the first transmit power to the second transmit power, wherein the wireless communication device 900 communicates according to a plurality of evaluation intervals including the evaluation interval, and wherein each evaluation interval of the plurality of evaluation intervals is associated with a respective baseline transmit power that is adjusted relative to a corresponding previous evaluation interval.

[0090] In some examples, the wireless communication device 900 may be capable of, configured to, or operable to communicate with at least one second wireless communication device using the second transmit power until the timer associated with the evaluation interval has expired.

[0091] In some examples, the PDU component 904 may be capable of, configured to, or operable to: output a second PDU using the second transmit power for transmission to at least one second wireless communication device via a communication link based on increasing the transmit power of the wireless communication device 900 from the first transmit power to the second transmit power during at least one sub-event, wherein the second PDU is transmitted during one or more sub-events after the at least one sub-event.

[0092] In some examples, the transmit power component 906 may be capable of, configured to, or operable to increase the transmit power of the wireless communication device 900 during an evaluation interval including at least one sub-event, wherein the wireless communication device 900 communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each evaluation interval of the plurality of evaluation intervals is associated with a respective baseline transmit power that is adjusted relative to a corresponding previous evaluation interval, and wherein the baseline transmit power of the evaluation interval is the first transmit power.

[0093] In some examples, the transmit power component 906 may be capable of, configured to, or operable to: adjust the transmit power of the wireless communication device 900 after an evaluation interval based on the NACK rate associated with the communication between the wireless communication device 900 and at least one second wireless communication device, the RSSI associated with the communication between the wireless communication device 900 and at least one second wireless communication device, or both.

[0094] The BLE audio component 912 may be capable of, configured to, or operable to include BLE audio data in an ISO PDU that is transmitted to at least one second wireless communication device according to the CIS between the wireless communication device 900 and at least one second wireless communication device.

[0095] Example embodiments are described in the numbered clauses below.

[0096] Clause 1: A method for wireless communication at a first wireless communication device, comprising: establishing a communication link with at least one second wireless communication device, wherein the communication link is associated with low energy audio communication between the first wireless communication device and the at least one second wireless communication device; transmitting one or more instances of a PDU to the at least one second wireless communication device via the communication link using a first transmit power, wherein the PDU is associated with a flush point; and transmitting at least one instance of the PDU to the at least one second wireless communication device via the communication link using a second transmit power that is higher than the first transmit power, wherein the at least one instance of the PDU is transmitted during at least one sub-event that is directly before the flush point associated with the PDU.

[0097] Clause 2: The method according to clause 1, further comprising: increasing the transmit power of the first wireless communication device from the first transmit power to the second transmit power during at least one sub-event based at least in part on a failure to receive an ACK message associated with one or more instances of the PDU transmitted using the first transmit power.

[0098] Clause 3: The method according to any one of clauses 1-2, further comprising: receiving, via the communication link, an ACK message associated with at least one instance of the PDU transmitted using the second transmit power from the at least one second wireless communication device; and reducing the transmit power of the first wireless communication device from the second transmit power to a third transmit power that is lower than the second transmit power based on receiving the ACK message.

[0099] Clause 4: The method according to Clause 3, wherein reducing the transmission power includes: after a certain number of ISO intervals have elapsed relative to the reception of an ACK message associated with at least one instance of the PDU, reducing the transmission power of the first wireless communication device from a second transmission power to a third transmission power.

[0100] Clause 5: The method according to any one of Clauses 1-4, further comprising: increasing the transmission power of the first wireless communication device from the first transmission power to the second transmission power during at least one of the sub-events, at least partially based on an instantaneous interference level associated with the communication link between the first wireless communication device and the at least one second wireless communication device.

[0101] Clause 6: The method according to any one of Clauses 1-5, further comprising: restarting a timer associated with an evaluation interval according to increasing the transmission power of the first wireless communication device from the first transmission power to the second transmission power, wherein the first wireless communication device communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each of the plurality of evaluation intervals is associated with a respective baseline transmission power adjusted relative to a corresponding previous evaluation interval; and communicating with the at least one second wireless communication device using the second transmission power until the timer associated with the evaluation interval has expired.

[0102] Clause 7: The method according to any one of Clauses 1-6, further comprising: sending a second PDU to the at least one second wireless communication device via the communication link using the second transmission power according to increasing the transmission power of the first wireless communication device from the first transmission power to the second transmission power during at least one of the sub-events, wherein the second PDU is sent during one or more sub-events after the at least one sub-event.

[0103] Clause 8: The method according to any one of Clauses 1-7, further comprising: increasing the transmission power of the first wireless communication device during an evaluation interval including the at least one sub-event, wherein the first wireless communication device communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each of the plurality of evaluation intervals is associated with a respective baseline transmission power adjusted relative to a corresponding previous evaluation interval, and wherein the baseline transmission power of the evaluation interval is the first transmission power.

[0104] Clause 9: The method according to Clause 8 further includes: adjusting the transmission power of the first wireless communication device after the evaluation interval, at least partially based on the NACK rate associated with the communication between the first wireless communication device and at least one second wireless communication device, the RSSI associated with the communication between the first wireless communication device and at least one second wireless communication device, or both.

[0105] Clause 10: The method according to any one of Clauses 1-9, wherein the at least one sub-event includes a single last sub-event before the flush point associated with the PDU.

[0106] Clause 11: The method according to any one of Clauses 1-10, wherein the second transmission power corresponds to the maximum transmission power of the first wireless communication device.

[0107] Clause 12: The method according to any one of Clauses 1-11, wherein the PDU includes an ISO PDU, and the ISO PDU includes BLE audio data.

[0108] Clause 13: The method according to any one of Clauses 1-12, wherein the at least one sub-event is part of a CIS event within an ISO interval.

[0109] Clause 14: An apparatus for wireless communication at a first wireless communication device, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method according to any one of Clauses 1 to 13.

[0110] Clause 15: An apparatus for wireless communication at a first wireless communication device, comprising: at least one unit for performing the method according to any one of Clauses 1 to 13.

[0111] Clause 16: A non-transitory computer-readable medium storing code for wireless communication at a first wireless communication device, the code including instructions executable by a processor to perform the method according to any one of Clauses 1 to 13.

[0112] As used herein, the term "determine" or "determining" encompasses a variety of operations, and thus, "determining" can include calculating, computing, processing, deriving, investigating, looking up (e.g., via looking up in a table, database, or another data structure), inferring, ascertaining, measuring, etc. Additionally, "determine" can include receiving (such as receiving information), accessing (such as accessing data stored in a memory), sending (such as sending information), etc. Further, "determine" can include resolving, selecting, obtaining, picking, establishing, and other such like actions.

[0113] As used herein, the phrase referring to "at least one of" a list of items refers to any combination of those items (which includes a single member). By way of example, "at least one of a, b, or c" is intended to cover: a, b, c, a - b, a - c, b - c, and a - b - c. As used herein, unless otherwise expressly stated, "or" is intended to be interpreted in an inclusive sense. For example, "a or b" can include only a, only b, or a combination of a and b.

[0114] As used herein, unless otherwise expressly indicated, "based on" is intended to be interpreted in an inclusive sense. For example, "based on" can be used interchangeably with "at least partially based on", "associated with", or "in accordance with", unless otherwise expressly indicated. Specifically, unless the phrase refers to "based solely on 'a'" or an equivalent in the context, either "based on 'a'" or "at least partially based on 'a'" can be based solely on "a" or on a combination of "a" and one or more other factors, conditions, or information.

[0115] The various illustrative components, logics, logic blocks, modules, circuits, operations, and algorithmic processes described in connection with the examples disclosed herein can be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. The interchangeability of hardware, firmware, and software has been described generally in terms of functionality and illustrated above in the various illustrative components, blocks, modules, circuits, and processes. Whether such functionality is implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0116] Various modifications to the examples described in this disclosure may be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of the disclosure. Accordingly, the claims are not intended to be limited to the examples shown herein but are to be accorded the widest scope consistent with the disclosure, the principles disclosed herein, and the novel features thereof.

[0117] In addition, the various features described in the context of separate examples in this specification can also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment can also be implemented separately or in any suitable sub-combination in multiple examples. Thus, although the features may have been described above as acting in a particular combination and even initially claimed as such, in some cases, one or more features from the claimed combination can be removed from the combination, and the claimed combination can be directed to a sub-combination or a variation of a sub-combination.

[0118] Similarly, although operations are depicted in the figures in a particular order, this should not be construed as requiring that the operations be performed in the particular order shown or in a sequential order, or that all of the illustrated operations be performed to achieve the desired result. Additionally, the figures may schematically illustrate one or more example processes in the form of a flowchart or a block diagram. However, other operations not depicted may be incorporated into the example processes schematically illustrated. For example, one or more additional operations may be performed before, after, concurrently with, or between any of the operations shown. In some cases, multitasking and parallel processing may be advantageous. Further, the separation of the various system components described in the examples above should not be construed as requiring such separation in all examples, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. An apparatus for wireless communication at a first wireless communication device, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: establish a communication link with at least one second wireless communication device, wherein the communication link is associated with low-energy audio communication between the first wireless communication device and the at least one second wireless communication device; send, via the communication link, one or more instances of a protocol data unit to the at least one second wireless communication device using a first transmit power, wherein the protocol data unit is associated with a flush point; and send, via the communication link, at least one instance of the protocol data unit to the at least one second wireless communication device using a second transmit power higher than the first transmit power, wherein the at least one instance of the protocol data unit is sent during at least one sub-event directly preceding the flush point associated with the protocol data unit.

2. The device according to claim 1, wherein, The instructions are further executable by the processor to cause the apparatus to: increase, during the at least one sub-event, the transmit power of the first wireless communication device from the first transmit power to the second transmit power, at least in part based on a failure to receive an acknowledgment message associated with the one or more instances of the protocol data unit sent using the first transmit power.

3. The device according to claim 1, wherein The instructions are further executable by the processor to cause the apparatus to: receive, via the communication link, an acknowledgment message associated with the at least one instance of the protocol data unit sent using the second transmit power from the at least one second wireless communication device; and reduce, in accordance with receiving the acknowledgment message, the transmit power of the first wireless communication device from the second transmit power to a third transmit power lower than the second transmit power.

4. The apparatus according to claim 3, wherein, To reduce the transmit power, the instructions are executable by the processor to cause the apparatus to: reduce, after a certain amount of isochronous (ISO) interval has elapsed relative to the reception of the acknowledgment message associated with the at least one instance of the protocol data unit, the transmit power of the first wireless communication device from the second transmit power to the third transmit power.

5. The device according to claim 1, wherein, The instructions are further executable by the processor to cause the apparatus to: increase, during the at least one sub-event, the transmit power of the first wireless communication device from the first transmit power to the second transmit power, at least in part based on an instantaneous interference level associated with the communication link between the first wireless communication device and the at least one second wireless communication device.

6. The device according to claim 1, wherein, The instructions are further executable by the processor to cause the apparatus to: Restart a timer associated with an evaluation interval based on increasing the transmit power of the first wireless communication device from the first transmit power to the second transmit power, wherein the first wireless communication device communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each evaluation interval of the plurality of evaluation intervals is associated with a respective baseline transmit power that is adjusted relative to a respective previous evaluation interval; and Communicate with the at least one second wireless communication device using the second transmit power until the timer associated with the evaluation interval has expired.

7. The device according to claim 1, wherein The instructions may further be executed by the processor to cause the device to perform the following operations: Based on increasing the transmit power of the first wireless communication device from the first transmit power to the second transmit power during the at least one sub-event, transmit a second protocol data unit to the at least one second wireless communication device via the communication link using the second transmit power, wherein the second protocol data unit is transmitted during one or more sub-events after the at least one sub-event.

8. The device according to claim 1, wherein, The instructions may further be executed by the processor to cause the device to perform the following operations: Increase the transmit power of the first wireless communication device during an evaluation interval including the at least one sub-event, wherein the first wireless communication device communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each evaluation interval of the plurality of evaluation intervals is associated with a respective baseline transmit power that is adjusted relative to a respective previous evaluation interval, and wherein the baseline transmit power of the evaluation interval is the first transmit power.

9. The device according to claim 8, wherein, The instructions may further be executed by the processor to cause the device to perform the following operations: Adjust the transmit power of the first wireless communication device after the evaluation interval based at least in part on a negative acknowledgment (NACK) rate associated with communication between the first wireless communication device and the at least one second wireless communication device, a received signal strength indicator (RSSI) associated with the communication between the first wireless communication device and the at least one second wireless communication device, or both.

10. The device according to claim 1, wherein, The at least one sub-event includes a single last sub-event before a flush point associated with the protocol data unit.

11. The device according to claim 1, wherein, The second transmit power corresponds to the highest transmit power of the first wireless communication device.

12. The device according to claim 1, wherein, The protocol data unit includes an isochronous (ISO) protocol data unit, and the isochronous protocol data unit includes Bluetooth Low Energy (BLE) audio data.

13. The apparatus according to claim 1, wherein, The at least one sub-event is part of a connected isochronous stream (CIS) event within an isochronous (ISO) interval.

14. A method for wireless communication at a first wireless communication device, comprising: Establish a communication link with at least one second wireless communication device, wherein the communication link is associated with low energy audio communication between the first wireless communication device and the at least one second wireless communication device; Transmit one or more instances of a protocol data unit over the communication link using a first transmit power, wherein the protocol data unit is associated with a flush point; and Transmit at least one instance of the protocol data unit over the communication link using a second transmit power that is higher than the first transmit power, wherein the at least one instance of the protocol data unit is transmitted during at least one sub-event that is directly before the flush point associated with the protocol data unit.

15. The method according to claim 14, further comprising: Increase the transmit power of the first wireless communication device from the first transmit power to the second transmit power during the at least one sub-event, at least in part based on a failure to receive an acknowledgment message associated with the one or more instances of the protocol data unit transmitted using the first transmit power.

16. The method according to claim 14, further comprising: Receive, over the communication link, an acknowledgment message associated with the at least one instance of the protocol data unit transmitted using the second transmit power from the at least one second wireless communication device; And Reduce the transmit power of the first wireless communication device from the second transmit power to a third transmit power that is lower than the second transmit power, based on receiving the acknowledgment message.

17. The method according to claim 16, wherein, Reducing the transmit power comprises: Reducing the transmit power of the first wireless communication device from the second transmit power to the third transmit power after a certain amount of isochronous (ISO) intervals have elapsed relative to the receipt of the acknowledgment message associated with the at least one instance of the protocol data unit.

18. The method according to claim 14, further comprising: Increase the transmit power of the first wireless communication device from the first transmit power to the second transmit power during the at least one sub-event, at least in part based on an instantaneous interference level associated with the communication link between the first wireless communication device and the at least one second wireless communication device.

19. The method according to claim 14, further comprising: Restart a timer associated with an evaluation interval based on increasing the transmit power of the first wireless communication device from the first transmit power to the second transmit power, wherein the first wireless communication device communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each evaluation interval of the plurality of evaluation intervals is associated with a respective baseline transmit power that is adjusted relative to a corresponding previous evaluation interval; and Communicate with the at least one second wireless communication device using the second transmit power until the timer associated with the evaluation interval has expired.

20. The method according to claim 14, further comprising: Based on increasing the transmit power of the first wireless communication device from the first transmit power to the second transmit power during the at least one sub-event, sending a second protocol data unit to the at least one second wireless communication device via the communication link using the second transmit power, wherein the second protocol data unit is sent during one or more sub-events after the at least one sub-event.

21. The method according to claim 14, further comprising: Increasing the transmit power of the first wireless communication device during an evaluation interval including the at least one sub-event, wherein the first wireless communication device communicates during a plurality of evaluation intervals including the evaluation interval, and wherein each evaluation interval of the plurality of evaluation intervals is associated with a respective baseline transmit power adjusted relative to a corresponding previous evaluation interval, and wherein the baseline transmit power of the evaluation interval is the first transmit power.

22. The method according to claim 21, further comprising: Adjusting the transmit power of the first wireless communication device after the evaluation interval based at least in part on a negative acknowledgment (NACK) rate associated with the communication between the first wireless communication device and the at least one second wireless communication device, a received signal strength indicator (RSSI) associated with the communication between the first wireless communication device and the at least one second wireless communication device, or both.

23. The method according to claim 14, wherein The at least one sub-event includes a single last sub-event before the flush point associated with the protocol data unit.

24. The method according to claim 14, wherein The second transmit power corresponds to the highest transmit power of the first wireless communication device.

25. The method according to claim 14, wherein, The protocol data unit includes an isochronous (ISO) protocol data unit, and the isochronous protocol data unit includes Bluetooth Low Energy (BLE) audio data.

26. The method according to claim 14, wherein The at least one sub-event is part of a connected isochronous stream (CIS) event within an isochronous (ISO) interval.

27. An apparatus for wireless communication at a first wireless communication device, comprising: Means for establishing a communication link with at least one second wireless communication device, wherein the communication link is associated with low energy audio communication between the first wireless communication device and the at least one second wireless communication device; A unit for sending one or more instances of a protocol data unit to the at least one second wireless communication device via the communication link using a first transmit power, wherein the protocol data unit is associated with a flush point; and A unit for sending at least one instance of the protocol data unit to the at least one second wireless communication device via the communication link using a second transmit power higher than the first transmit power, wherein the at least one instance of the protocol data unit is sent during at least one sub-event directly before the flush point associated with the protocol data unit.

28. The apparatus according to claim 27, further comprising: A unit for increasing the transmission power of the first wireless communication device from the first transmission power to the second transmission power during the at least one sub-event, at least in part based on a failure to receive an acknowledgment message associated with the one or more instances of the protocol data unit transmitted using the first transmission power.

29. A non-transitory computer-readable medium storing code for wireless communication at a first wireless communication device, the code including instructions executable by a processor to perform the following operations: Establish a communication link with at least one second wireless communication device, wherein, The communication link is associated with low-energy audio communication between the first wireless communication device and the at least one second wireless communication device; Transmitting one or more instances of a protocol data unit to the at least one second wireless communication device via the communication link using a first transmission power, wherein the protocol data unit is associated with a flush point; and Transmitting at least one instance of the protocol data unit to the at least one second wireless communication device via the communication link using a second transmission power higher than the first transmission power, wherein the at least one instance of the protocol data unit is transmitted during at least one sub-event directly preceding the flush point associated with the protocol data unit.

30. The non-transitory computer-readable medium according to claim 29, wherein, The instructions are further executable by the processor to perform the following operations: Increasing the transmission power of the first wireless communication device from the first transmission power to the second transmission power during the at least one sub-event, at least in part based on a failure to receive an acknowledgment message associated with the one or more instances of the protocol data unit transmitted using the first transmission power.

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