Reducing listen mode power consumption of wireless local area network (WLAN) devices

Abstract

This disclosure provides methods, apparatus, and systems for reducing power consumption when a station (STA) operates in a listening mode. In some aspects, to reduce power consumption in listening mode, the STA can alternate between monitoring a radio channel to search for packets and not monitoring the radio channel. When the STA monitors the radio channel to search for packets in listening mode, the STA can configure a packet detection component to a power-on state. When the STA is not monitoring the radio channel in listening mode, the STA can configure the packet detection component to a power-off state. During the power-on state of listening mode, the STA can detect the preamble of packets transmitted on the radio channel. In response to detecting the preamble of the packet, the STA can switch from listening mode to receive mode to process the packet.

Description

[0001] Cross-references to related applications

[0002] This patent application claims priority to U.S. nonprovisional patent application No. 17 / 214,481, filed March 26, 2021, entitled “REDUCING LISTEN MODE POWERCONSUMPTION OF A WIRELESS LOCAL AREA NETWORK (WLAN) DEVICE,” which has been assigned to the assignee of this application. The disclosure of that earlier application is considered part of this patent application and is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to the field of wireless communications, and specifically to reducing the power consumption of wireless local area network (WLAN) devices operating in listening mode.

[0004] Related technical descriptions

[0005] A Wireless Local Area Network (WLAN) can be formed by one or more wireless access points (APs) that provide a shared wireless communication medium for use by multiple client devices (also known as wireless stations (STAs)). The basic building block of a WLAN conforming to the IEEE 802.11 family of standards is the Basic Service Set (BSS) managed by the AP. Each BSS is identified by a Service Set Identifier (SSID) advertised by the AP. The AP periodically broadcasts beacon frames to enable other STAs within its wireless range to establish or maintain a communication link with the WLAN.

[0006] In a WLAN, the STA can monitor the wireless channel to look for packets or other information. If the STA detects a packet on the wireless channel, it can receive the packet and perform operations to process it. The STA can operate in various modes while performing operations to monitor the wireless channel, detect packets, and receive packets. For example, the STA can operate in listen mode when monitoring the wireless channel. The STA can operate in receive mode when receiving and processing packets. When the STA does not expect to communicate on the wireless channel, it can operate in sleep mode, in which the STA does not expend resources monitoring the wireless channel.

[0007] Overview

[0008] The systems, methods, and apparatus disclosed herein each have several innovative aspects, and no single aspect is solely responsible for the desired properties disclosed herein.

[0009] One innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication performed by a device of a first access point (AP) in a wireless local area network (WLAN). The method may include causing one or more components of the first WLAN device to alternate between a power-off state and a power-on state during a listening mode of the first WLAN device. The method may include receiving preamble information from a packet from a second WLAN device during the power-on state.

[0010] Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus of a first WLAN device for wireless communication. The apparatus of the first WLAN device may include a processor configured to cause one or more components of the first WLAN device to alternate between a power-off state and a power-on state during a listening mode of the first WLAN device. The apparatus of the first WLAN device may include an interface configured to receive preamble information of packets from a second WLAN device during the power-on state.

[0011] Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transient computer-readable medium storing instructions that, when executed by a processor of a first WLAN device, cause the first WLAN device to perform operations for communication within the WLAN. These operations enable the first WLAN device to: cause one or more components of the first WLAN device to alternate between a power-off state and a power-on state during the first WLAN device's listening mode. These operations also enable the first WLAN device to: obtain preamble information for packets from a second WLAN device during the power-on state.

[0012] Another innovative aspect of the subject matter described in this disclosure can be implemented in the apparatus of a first WLAN device for wireless communication. The apparatus of the first WLAN device may include means for alternating one or more components of the first WLAN device between a power-off state and a power-on state during a listening mode of the first WLAN device. The apparatus of the first WLAN device may include means for obtaining preamble information of packets from a second WLAN device during the power-on state.

[0013] The various aspects of the subject matter described in this disclosure can be implemented in devices, software programs, systems or other apparatuses used to perform the methods described above.

[0014] Details of one or more aspects of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from this description, the drawings, and the claims. It should be noted that the relative dimensions in the following drawings may not be drawn to scale. Brief description of the attached diagram

[0016] Figure 1 A system diagram of an example wireless communication network is shown.

[0017] Figure 2 The diagram illustrates how an Explanatory Station (STA) alternates between various modes and power states while monitoring and processing packets on a wireless channel.

[0018] Figure 3 The illustration shows a STA monitoring beacon frames on a wireless channel, alternating between various modes and power states.

[0019] Figure 4 This is a block diagram illustrating an example STA, which includes a power state controller that controls the power state of the STA.

[0020] Figure 5 An example of alternating listening modes between power-on and power-off states is shown when monitoring Physical Layer (PHY) Protocol Data Units (PPDUs).

[0021] Figure 6 Example operations, timing, and power status of the packet preamble for detecting the PPDU in listening mode are shown.

[0022] Figure 7 A process for wireless communication in a wireless local area network (WLAN) is described, including example operations performed by a device of a STA.

[0023] Figure 8 A block diagram of an example wireless communication device is shown.

[0024] Figure 9A A block diagram of an example access point (AP) is shown.

[0025] Figure 9B A block diagram of an example STA is shown.

[0026] Figure 10 A block diagram of an example electronic device for implementing various aspects of this disclosure is shown.

[0027] Similar reference numerals and naming conventions in the various figures indicate similar elements.

[0028] Detailed description

[0029] The following description relates to certain aspects of the inventiveness of this disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. Examples in this disclosure are based on Wireless Local Area Network (WLAN) communication according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standard. However, the described aspects 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: the IEEE 802.11 standard, Bluetooth standard, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), GSM / General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunking Radio (TETRA), Wideband CDMA (W-CDMA), Evolved Data Optimized (EV-DO), 1xEV-DO, EV-DO Revision A, EV-DO Revision B, High-Speed ​​Packet Access (HSPA), High-Speed ​​Downlink Packet Access (HSDPA), High-Speed ​​Uplink Packet Access (HSUPA), Evolved High-Speed ​​Packet Access (HSPA+), Long Term Evolution (LTE), AMPS, or other known signals used for communication in wireless networks, cellular networks, or Internet of Things (IoT) networks (such as systems utilizing 3G, 4G, 5G, or 6G or further implementations thereof).

[0030] A wireless local area network (WLAN) in a home, apartment, business, or other type of environment may include two or more WLAN devices. A WLAN may include one or more access points (APs) and one or more stations (STAs). An AP is a STA that performs distributed system access functions in a WLAN. For simplicity, this disclosure refers to a WLAN device that can be operated as an AP or STA. An AP can provide wireless access to STAs located in the coverage area of ​​the AP. STAs may include various types of WLAN devices, such as mobile phones, laptops, gaming systems (including virtual reality and augmented reality systems (VR and AR, or collectively referred to as XR)), entertainment systems, smart appliances, wearable devices, and IoT devices. Some APs may be able to establish connectivity via more than one frequency band. For example, an AP may operate a first basic service set (BSS) on a first frequency band (such as the 2.4 GHz band) and a second BSS on a second frequency band (such as the 5 GHz band). For simplicity, the first BSS and the second BSS may be referred to as the first frequency band of the AP and the second frequency band of the AP, respectively.

[0031] In a WLAN, the STA can utilize various operating modes, including listen mode, receive mode, and sleep mode. In listen mode, the STA continuously monitors the wireless channel for packets. To continuously monitor the wireless channel in listen mode, the STA continuously supplies power to the packet detection component on the wireless channel. If the STA detects a packet, it can enter receive mode to process the detected packet. While processing packets in receive mode, the STA continuously consumes power. If the STA anticipates not communicating for a relatively long period, it can enter sleep mode, in which it stops monitoring the wireless channel. In sleep mode, the STA conserves power because it stops supplying power to the packet detection component. The STA can notify the AP before entering sleep mode, so the AP will not transmit packets to the STA while it is in sleep mode. The AP can resume transmitting packets to the STA after it exits sleep mode. Operating in sleep mode can result in higher packet delivery latency, thus the STA can avoid sleep mode in many scenarios. To avoid sleep mode, the STA can spend a significant amount of time continuously supplying power to the packet detection component in listen mode.

[0032] Various aspects of this disclosure generally relate to techniques for saving power when a STA is monitoring a radio channel to search for packets. Some aspects more specifically relate to a STA that enables a reduced-power listening mode. To reduce power consumption in listening mode, the STA can alternate between monitoring the radio channel to search for packets and not monitoring the radio channel. When the STA is monitoring the radio channel to search for packets in listening mode, the STA can configure its packet detection component to a power-on state. When the STA is not monitoring the radio channel in listening mode, the STA can configure its packet detection component to a power-off state. The packet detection component of the STA may include one or more components of the RF front end, an analog-to-digital converter (ADC), and one or more components of the baseband processing unit. In some implementations, the STA can alternate between the power-on and power-off states based on a duty cycle, as further described herein. During the power-on state of listening mode, the STA can detect the preamble of packets transmitted on the radio channel. In response to detecting the preamble of a packet, the STA can switch from listening mode to receive mode. In receive mode, the STA can remain in the power-on state to receive and process packets.

[0033] In some implementations, in listen mode, the STA can detect packet preambles by performing autocorrelation on information received on the radio channel. For example, the STA can perform autocorrelation to detect information from the legacy short training field (L-STF) and legacy long training field (L-LTF) of the Physical Layer (PHY) Protocol Data Unit (PPDU). In listen mode, the STA's packet detection component can remain powered on for the duration allowing the STA to perform autocorrelation. If the STA does not detect a packet preamble, it can switch to a power-down state in listen mode. However, if the STA detects a packet preamble, it can remain powered on and enter receive mode, where it processes packets. In some implementations, the time spent performing autocorrelation in the power-on state can be based on the Received Signal Strength Indicator (RSSI) associated with the packet, channel condition metrics (such as signal-to-noise ratio or channel congestion), or other suitable metrics, as further described herein.

[0034] In some implementations, the STA can detect packet preambles by performing match filtering on the information received on the wireless channel. For example, the STA can perform match filtering to detect the L-STF and L-LTF symbols of the PPDU. If the STA does not detect the preamble, it can enter a power-off state in a listening mode.

[0035] Specific implementations of the subject matter described herein can achieve one or more of the following potential advantages. Conventional techniques for monitoring a wireless channel in listen mode may involve continuously powering a packet detection component as it continuously monitors the wireless channel. In some implementations, the STA may intermittently monitor the wireless channel in listen mode to search for a packet preamble. By intermittently monitoring the wireless channel, the STA can reduce the power consumed during listen mode. For STAs without cooling fans, reduced power consumption allows the STA to operate at lower temperatures. For STAs operating on battery power, reduced power consumption can extend the STA's battery life. The techniques described herein can further reduce the STA's power consumption because future wireless standards (such as the future IEEE 802.11 standard) may change the packet preamble. For example, based on future modifications to the packet preamble, some STA implementations may spend more time in a power-off state while intermittently monitoring the wireless channel. Since WLANs typically include multiple STAs, the power savings can be significant.

[0036] Figure 1A system diagram of an example wireless communication network 100 is shown. According to some aspects, the wireless communication network 100 may be an example of a wireless local area network (WLAN) (such as a Wi-Fi network) (and will be referred to WLAN 100 below). For example, WLAN 100 may be a network implementing at least one of the IEEE 802.11 standard family (such as standards defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11aa, 802.11ah, 802.11ad, 802.11aq, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be). WLAN 100 may include numerous WLAN devices, such as access points (APs) 102 and multiple stations (STAs) 104 having wireless associations with APs 102. Although only one AP 102 is shown, WLAN 100 may also include multiple APs 102. The IEEE 802.11-2016 standard defines a STA as an addressable unit. An AP is an entity that contains at least one STA and provides access to associated STAs via a wireless medium (WM) for access to distribution services (such as another network, not shown). Therefore, an AP includes both the STA and Distribution System Access Function (DSAF). Figure 1 In the example, AP 102 may be connected to a gateway device (not shown) that provides connectivity to another network 140. The DSAF of AP 102 can provide access between STA 104 and the other network 140. Although AP 102 is described as an access point using infrastructure mode, in some implementations, AP 102 may be a conventional STA operating as an AP. For example, AP 102 may be a STA capable of operating in peer-to-peer or stand-alone mode. In some other examples, AP 102 may be a software AP (SoftAP) operating on a computer system. Each STA 104 may also be referred to as a mobile station (MS), mobile device, mobile handheld device, wireless handheld device, access terminal (AT), user equipment (UE), subscriber station (SS), or subscriber unit, etc. STA104 can refer to a variety of devices, such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, laptops, tablets, laptops, display devices (e.g., TVs, computer monitors, navigation systems, etc.), music or other audio or stereo devices, remote control devices (“remote controllers”), printers, kitchen or other household appliances, remote key fobs (e.g., for passive keyless entry and start (PKES) systems), and so on.

[0037] A single AP 102 and its associated set of STAs 104 may be referred to as a Basic Service Set (BSS), which is managed by the corresponding AP 102. Figure 1 Example coverage area 108 of AP 102 is shown, which may represent the Basic Service Area (BSA) of WLAN 100. The BSA can be identified to users by a Service Set Identifier (SSID) and to other devices by a Basic Service Set Identifier (BSSID), where the BSSID may be the Media Access Control (MAC) address of AP 102. AP 102 periodically broadcasts a beacon including the BSSID to enable any STA 104 within the wireless range of AP 102 to establish or maintain a corresponding communication link 106 with AP 102 (hereinafter also referred to as a "Wi-Fi link"). For example, the beacon may include an identifier of the primary channel used by the corresponding AP 102 and a timing synchronization function for establishing or maintaining timing synchronization with the AP. AP 102 can provide access to external networks (such as network 140) to each STA 104 in the WLAN via the corresponding communication link 106. In order to establish a communication link 106 with AP 102, each STA 104 is configured to perform passive or active scanning operations (“scanning”) on frequency channels in one or more frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, or 60 GHz bands). To perform a passive scan, STA 104 listens for beacons transmitted by the corresponding AP 102 at periodic time intervals (referred to as Target Beacon Transmission Time (TBTT) (measured in units of time (TU), where one TU can be equal to 1024 microseconds (μs)). To perform an active scan, STA 104 generates probe requests and transmits these probe requests sequentially on each channel to be scanned, and listens for probe responses from AP 102. Each STA 104 can be configured to identify or select an AP 102 to associate with based on scan information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 106 with the selected AP 102. AP 102 can assign an Association Identifier (AID) to STA 104 at the end of the association operation, and AP 102 uses the AID to track STA 104.

[0038] As wireless networks become increasingly prevalent, STA 104 can have the opportunity to choose from one of many BSSs within its range or from multiple APs 102 that together form an Extended Service Set (ESS) (comprising multiple connected BSSs). The extended network station associated with WLAN 100 can be connected to a wired or wireless distribution system that allows multiple APs 102 to be connected in such an ESS. Thus, 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 being associated with an AP 102, STA 104 can also be configured to periodically scan its surroundings to find a more suitable AP 102 to associate with. For example, a STA 104 moving relative to its associated AP 102 can perform a "roaming" scan to find another AP 102 with more suitable network characteristics (such as a higher RSSI or reduced traffic load).

[0039] In some scenarios, STA 104 can form a network without AP 102 or other equipment besides STA 104 itself. An example of such a network is an ad hoc network (or wireless ad hoc network). Ad hoc networks are alternatively referred to as mesh networks or peer-to-peer (P2P) networks. In some scenarios, ad hoc networks can be implemented within a larger wireless network (such as WLAN 100). In such implementations, while STA 104 can communicate with each other via communication link 106 through AP 102, STA 104 can also communicate directly with each other via direct wireless link 107. Furthermore, two STA 104 can communicate via direct communication link 107 regardless of whether the two STA 104 are associated with and served by the same AP 102. In such ad hoc systems, one or more STA 104 can assume the role played by AP 102 in the BSS. Such STA 104 can be referred to as the group owner (GO) and can coordinate transmissions within the ad hoc network. Examples of direct wireless links 107 include Wi-Fi Direct connections, connections established using Wi-Fi Tunneling Direct Link Establishment (TDLS) links, and other P2P group connections.

[0040] AP 102 and STA 104 function and communicate (via the corresponding communication link 106) in accordance with the IEEE 802.11 standard family, such as standards defined by the IEEE 802.11-2016 specification or its revisions, including but not limited to 802.11aa, 802.11ah, 802.11aq, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. These standards define the WLAN radio and baseband protocols used for the PHY and Media Access Control (MAC) layers. AP 102 and STA 104 transmit and receive wireless communications (also referred to below as "Wi-Fi communication") to and from each other in the form of Physical Layer Convergence Protocol (PLCP) Protocol Data Units (PPDUs).

[0041] Each frequency band may include multiple subbands or frequency channels. For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax, and 802.11be standard revisions can be transmitted in the 2.4 GHz and 5 GHz frequency bands, where each frequency band is divided into multiple 20 MHz channels. Thus, these PPDUs are transmitted on physical channels with a minimum bandwidth of 20 MHz, but larger channels can be formed through channel bonding. For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax, and 802.11be standard revisions can be transmitted on physical channels with bandwidths of 40 MHz, 80 MHz, 80+80 MHz, 160 MHz, 160+160 MHz, or 320 MHz by bonding two or more contiguously or non-contiguously allocated 20 MHz channels together. For example, IEEE 802.11n describes the use of up to two channels (resulting in a combined 40 MHz bandwidth) and defines a high-throughput (HT) transmission format. IEEE 802.11ac describes the use of up to eight channels (resulting in a maximum combined 160 MHz bandwidth) and defines a very high-throughput (VHT) transmission format. IEEE 802.11ax also supports up to a combined 160 MHz bandwidth (which can be a combination of eight channels, each with a width of 20 MHz). IEEE 802.11be can support up to a combined 320 MHz bandwidth (which is a combination of 16 channels, each with a width of 20 MHz).

[0042] AP 102 and STA 104 in WLAN 100 can transmit PPDUs on unlicensed spectrum, which can be a portion of a spectrum that includes bands traditionally used by Wi-Fi technologies, such as the 2.4 GHz band, 5 GHz band, 60 GHz band, and 900 MHz band. Some implementations of AP 102 and STA 104 described herein can also communicate in other bands, such as the 6 GHz band, that can support both licensed and unlicensed communication. AP 102 and STA 104 can also be configured to communicate on other bands, such as shared licensed bands, where multiple operators may have licenses to operate in one or more of the same or overlapping bands.

[0043] Each PPDU is a composite structure comprising a PHY preamble, a PHY header, and a payload in the form of a PLCP Service Data Unit (PSDU). For example, a PSDU may include a PHY preamble and header (which may be referred to as a PLCP preamble and header) and one or more MAC Protocol Data Units (MPDUs). The information provided in the PHY preamble and header can be used by the receiving equipment to decode subsequent data in the PSDU. In instances where the PPDU is transmitted over bonded channels, the preamble and header fields may be copied and transmitted in each of multiple component channels. The PHY preamble can be used for packet detection, automatic gain control, channel estimation, and other purposes. The information provided in the PHY header is formatted and encoded based on the specific IEEE 802.11 protocol to be used to transmit the payload and typically includes signaling fields (such as SIG-A and SIG-B fields) containing BSS and addressing information such as BSS color and STA ID.

[0044] Figure 2 Figure 200 illustrates an example STA 201 switching between various modes and power states while monitoring packets on wireless channel 211. STA 201 can monitor wireless channel 211 to locate packets transmitted by AP 202. AP 202 is a reference... Figure 1 An example of AP 102 is described. STA 201 is a reference. Figure 1An example of STA 104 is described. STA 201 can alternate between receive mode and listen mode. Pattern diagram 205 shows an example of STA 201 alternating between receive mode 206 and listen mode 208. In receive mode 206, the packet detection component of STA 201 may remain powered on to process packets received on wireless channel 211. In some implementations, the packet detection component of STA 201 may include one or more components of the RF front end, an ADC, and one or more components of the baseband processing unit. In listen mode 208, STA 201 may intermittently monitor wireless channel 211 to look for packets. For example, STA 201 may alternate between monitoring wireless channel 211 to look for packets and not monitoring wireless channel 211, such as packets transmitted by AP 202. When monitoring wireless channel 211 in listen mode 208, STA 201 may configure the packet detection component to be powered on. When not monitoring wireless channel 211 in listening mode 208, STA 201 can configure the packet detection component to a power-off state, such as further... Figure 4-6 As described in [the document]. For example, in listening mode 208, STA 201 can cause one or more components of the RF front end, ADC, and baseband processing unit to alternate between a power-off state and a power-on state.

[0045] Power state diagram 213 shows an example of STA 201 alternating between a power-on state and a power-off state. Alternating between power-on and power-off states can also be referred to as switching between various power states. Timeline 209 shows the time progress from left to right. Figure 2 As shown, AP 202 can transmit the first packet 203 on wireless channel 211. STA 201 can enter receive mode 206 (at time = 0) to receive and begin processing the first packet 203. In receive mode 206, the packet detection component of STA 201 can remain powered on (see segment 212 of power state diagram 213) to receive and process the first packet 203. After receiving the first packet 203, STA 201 can switch to listen mode 208.

[0046] STA 201 can enter a listening mode 208 (at time = 7), in which STA 201 intermittently monitors the wireless channel 211 for packets. While monitoring the wireless channel 211 in listening mode 208, STA 201 can configure the packet detection component to a power-on state (e.g., at segment 214 of the power state graph 213). For example, STA 201 can provide power to the packet detection component to enter the power-on state. When not monitoring the wireless channel 211 in listening mode 208, STA can configure the packet detection component to a power-off state (e.g., at segment 215 of the power state graph 213). For example, STA 201 can stop providing power to the packet detection component to enter the power-off state, as shown in... Figure 4-6 Further described in the text. In some implementations, the duration of the power-on state may be approximately the same as the duration of the power-off state. Power state diagram 213 shows that the power-off state lasts for a single time unit and the power-on state lasts for a single time unit. However, the power-on and power-off states may have any suitable duration. In some implementations, the duration of the power-on state may differ from the duration of the power-off state. For example, the power-off state may last for a single time unit, and the power-on state may last for one and a half time units. In some implementations, STA 201 may alternate between the power-on and power-off states based on a configured duty cycle. For example, the duty cycle may be 50% when the duration of the power-on state is the same as the duration of the power-off state. Reference Figure 6 Describes the additional duty cycle. After detecting the second packet 204, STA 201 can switch to receive mode 206.

[0047] like Figure 2 As shown, AP 202 can transmit a second packet 204 on wireless channel 211 (at time = 16). STA 201 can detect the second packet 204 and change from listening mode 208 to receiving mode 206. The transition from listening mode 208 to receiving mode 206 is... Figure 5 and 6 Further description follows. While in receive mode 206, the packet detection component may remain powered on to receive and process the second packet 204 (see segment 216 of power state diagram 205). STA 201 may remain in receive mode 206 until processing of the second packet 204 is complete. STA 201 may then switch to listen mode (not shown), and this process may continue to repeat accordingly.

[0048] Figure 3A diagram 300 illustrates an example of STA 201 alternating between various modes and power states while monitoring beacon frames on radio channel 211. STA 201 can monitor radio channel 211 to look for beacon frames from AP 202. STA 201 can switch between listening mode, receiving mode, and sleep mode. Mode diagram 305 shows an example of STA 201 alternating between listening mode 208, receiving mode 206, and sleep mode 304. In sleep mode 304, STA 201 can enter a power-off state, in which STA 201 stops providing power to the packet detection component. STA 201 can determine the duration of sleep mode 304 based on the time interval at which AP broadcasts beacon frames on radio channel 211. In some implementations, the time interval can be indicated in the Delivery Traffic Interval Message (DTIM) included in the beacon frame (such as the first beacon frame 303). AP 202 can enter sleep mode 304 between beacon frames and immediately "wake up" to listen mode 208 to detect the next beacon frame. If a beacon frame is detected during listen mode 208, STA 201 can enter receive mode 206, in which STA 201 processes the beacon frame.

[0049] Power state diagram 313 illustrates an example of STA 201 alternating between a power-on state and a power-off state. Timeline 309 shows the time progress from left to right. As shown, STA 201 can enter listen mode 208, in which STA 201 intermittently monitors the radio channel to search for beacon frames. In listen mode 208, STA 201 can cause the packet detection component to alternate between a power-on state and a power-off state. During the power-on state, STA 201 can provide power to the packet detection component and monitor the radio channel 211. During the power-off state, STA 201 can stop providing power to the packet detection component and stop monitoring the radio channel 211, as in... Figure 4-6 Further details are provided below.

[0050] like Figure 3 As shown, AP 202 can transmit a first beacon frame 303 on wireless channel 211. STA 201 can detect the first beacon frame 303 and enter receive mode 206. During receive mode 206, STA 201 can remain powered on to process the first beacon frame 303.

[0051] like Figure 3 As shown, STA 201 can enter sleep mode 304. During sleep mode 304, STA 201 can configure its packet detection component to be powered off. The duration of sleep mode 304 can depend on the time interval at which AP 202 broadcasts beacon frames on radio channel 211. STA 201 can wake up from sleep mode 304 and enter listening mode 208. Figure 3As shown, AP202 can transmit a second beacon frame 312. STA 201 can detect the second beacon frame 312 and enter receive mode 206, during which STA 201 can process the second beacon frame 312.

[0052] Figure 4 This is a block diagram illustrating example STA 201, which includes a power state controller 404 that controls the power state of STA 201. STA 201 may include the power state controller 404, an RF front end 406, an ADC 408, and a baseband processing unit 410. (As shown in...) Figure 2 and 3 As described, the RF front-end 406, ADC 408, and baseband processing unit 410 may be referred to as a packet detection assembly. A power state controller 404 may be communicatively coupled to the RF front-end 406, ADC 408, and baseband processing unit 410. The RF front-end 406 may include an RF amplifier (RFA) 416, such as a low-noise amplifier. The RF front-end 406 may also include a mixer 414, a filter 412, and a synthesizer and phase-locked loop (PLL) 418. The ADC 408 may convert analog radio information into digital information associated with packets. The baseband processing unit 410 may use various filters and digital processing components, such as a baseband processor, to process the digital information. For example, during a listening mode, the baseband processing unit 410 may perform autocorrelation to detect the packet preamble. For example, the baseband processing unit 410 may perform autocorrelation to detect the STF of the packet preamble, as in... Figure 5 and 6 As further described below. As another example, during monitoring mode, the baseband processing unit can perform match filtering to detect block preambles in digital information.

[0053] The power state controller 404 can configure the packet detection components to a power-on state and a power-off state based on the STA's operating mode. In some implementations, when the STA 201 is operating in listen mode, the power state controller 404 can configure one or more components of the RF front-end 406 to a power-off state. For example, the power state controller 404 can configure RFA416 of the RF front-end 406 to a power-off state. In some implementations, when the STA 201 is operating in listen mode, the power state controller 404 can configure the ADC 408 or one or more components thereof (not shown) to a power-off state. In some implementations, when the STA 201 is operating in listen mode, the power state controller 404 can configure the baseband processing unit 410 or one or more components thereof (not shown) to a power-off state.

[0054] In some implementations, the power state controller 404 can continuously supply power to the synthesizer and PLL 418 of the RF front-end 406. For example, the synthesizer and PLL 418 can remain powered on even when the RFA 416, mixer 414, and filter 412 are powered off. During listen mode, the power state controller 404 can also continuously supply power to certain filters and components of the baseband processing unit 410, even when the RFA 416 or other components are powered off. During sleep mode, the power state controller 404 can configure all components of the RF front-end 406, ADC 408, and baseband processing unit 410 to a powered-off state. During receive mode, the power state controller 404 can configure all components of the RF front-end 406, ADC 408, and baseband processing unit 410 to a powered-on state.

[0055] Figure 5 An example of alternating listening modes between power-on and power-off states while monitoring a PPDU is shown. In some implementations, STA 201 can detect and process legacy PPDU 502 in listening mode. Legacy PPDU 502 may include preambles comprising L-STF 504, L-LTF 506, and a legacy signal (L-SIG) field 508. Legacy PPDU 502 may also include a data field 510. In some implementations, STA 201 can detect and process mixed-mode PPDU 511 in listening mode. Mixed-mode PPDU 511 may include legacy preambles and may also include one or more next-generation preambles, such as HT preambles, VHT preambles, and Extremely High Throughput (EHT) preambles. Figure 5 As shown, in one example, the hybrid-mode PPDU 511 may include both legacy preamble and HT preamble, and may include L-STF 512, L-LTF 514, L-SIG 516, HT-SIG 518, HT-STF 520, HT-LTF 522, and data field 526. When the PPDU is transmitted over the wireless channel, the transmission of L-STFs (such as L-STF 504 or L-STF 512) and other fields (such as L-LTF 506 or L-LTF 514) may have certain durations defined by the IEEE 802.11 standard. For example, the transmission of L-STF 504 and L-STF 512 may each have a duration of approximately 8 μs. In some implementations, L-STF 504 and L-STF 512 may each include STF information repeated ten times over 8 μs, as shown in... Figure 6As further described below. In some implementations, L-LTF 506 and L-LTF 514 may each have a duration of approximately 8 μs. In some implementations, L-LTF 506 and L-LTF 514 may each include LTF information transmitted over 8 μs, such as configuration information, as described in... Figure 6 Further details are provided below.

[0056] like Figure 5 As shown, STA 201 can operate in listen mode while the legacy PPDU 502 is transmitting over the wireless channel. Transmission of the legacy PPDU 502 can occur at any time during listen mode. Therefore, reception of L-STF 504 can occur when STA 201 is monitoring the wireless channel (power-on state) or when STA is not monitoring the wireless channel (power-off state). To avoid missing L-STF 504, STA 201 can use a duty cycle that alternates between monitoring (power-on state) and not monitoring (power-off state), enabling detection of L-STF 504 within an 8μs transmission period. For example, in some implementations, STA 201 may be able to detect L-STF 504 via autocorrelation over at least two power state cycles (in... Figure 6 (Further described below), where the power state cycles include power-on and power-off states with durations based on duty cycle. In some implementations, the number of power state cycles used to detect the L-STF 504 may depend on the RSSI associated with the legacy PPDU 502. For example, when the RSSI is greater than a first RSSI threshold, the STA 201 may detect the L-STF 504 in two power state cycles. As a non-limiting example, the first RSSI threshold may be approximately -85 dBm. When the RSSI is approximately less than -85 dBm, the STA 201 may detect the L-STF 504 in more power state cycles. In some implementations, the number of power state cycles used to detect the L-STF 504 may depend on channel condition metrics (such as signal-to-noise ratio or channel congestion) or other suitable metrics. For example, when the signal-to-noise ratio (SNR) is below the SNR threshold, the STA 201 can detect the L-STF 504 in two power state cycles, and when the SNR is above the SNR threshold, the STA 201 can detect the L-STF 504 in more power state cycles. Figure 6 Additional details about the detection group preamble are provided in the description.

[0057] Power graph 531 shows that STA 201 causes the packet detection component to alternate between a power-on state and a power-off state to detect L-STF 504 or L-STF 512. STA 201 may alternate between the power-on and power-off states based on a duty cycle. According to power graph 531, STA 201 may operate in a first power-on state 537 of listening mode 208. Timing line 534 shows that STA 201 may receive at least a portion of L-STF 504 during the first power-on state 537. During the first power-on state 537, STA 201 is monitoring the radio channel while L-STF 504 (or L-STF 512) is received. Although the following example describes receiving L-STF 504 of legacy PPDU 502, similar steps may be performed to receive L-STF 512 of mixed-mode PPDU 511. In some implementations, STA 201 can detect L-STF 504 if it has sufficient time in the power-on state to detect at least two repetitions of the STF information in L-STF 504, as in Figure 6 Further details are provided below. For example... Figure 5 As shown, STA 201 can receive L-STF, but in the first power-on state 537, there is insufficient time to detect L-STF 504 (e.g., by detecting two repetitions of STF information via autocorrelation). As shown, since L-STF 504 is not detected, STA 201 can switch to a power-off state 538 based on the duty cycle, and thus STA 201 can stop monitoring the radio channel until the next power-on state. During the second power-on state 540, STA 201 can resume operation for monitoring the radio channel to look for preamble information (such as L-STF 504). In the second power-on state 540, STA 201 can detect L-STF 504 (e.g., by detecting two repetitions of STF information via autocorrelation). After detecting L-STF 504, STA 201 can switch to receive mode 206 to process the legacy PPDU 502 in the power-on state. In some implementations, STA 201 can detect L-STF 504 by detecting any suitable number of repetitions of the STF information of L-STF 504 in any suitable number of power-on states. The number of STF repetitions and the number of power-on states used to detect L-STF 504 may depend on the specific grouping detection technique (such as autocorrelation).

[0058] In some implementations, STA 201 may determine whether to alternate between a power-on and power-off state during listen mode based on the RSSI associated with the packet (such as legacy PPDU 502 or mixed-mode PPDU 511). For example, if the RSSI is greater than an RSSI threshold (such as -85 dBm), STA 201 may alternate between a power-on and power-off state during listen mode. As another example, if the RSSI is less than a first RSSI threshold (such as -60 dBm) and greater than a second RSSI threshold (such as -85 dBm), STA 201 may alternate between a power-on and power-off state during listen mode. However, if the RSSI is less than the second RSSI threshold (-85 dBm), STA 201 may remain in the power-on state throughout the listen mode.

[0059] Figure 6 Example operation, timing, and power status of the packet preamble 602 for detecting the PPDU 600 in monitoring mode are shown. The packet preamble 602 may include L-STF 604, L-LTF 606, and other information 603 (such as packet payload). When the PPDU is transmitted over the wireless channel, the transmission of certain fields may have certain durations defined by technical standards (such as the IEEE 802.11 standard). For example, the transmission of L-STF 604 may have a duration of approximately 8 μs. In some implementations, L-STF 604 may include STF information (such as OFDM symbols), which is repeated ten times over 8 μs, as shown in... Figure 6 As shown in the diagram. In some implementations, the transmission of L-LTF 606 can have a duration of approximately 8 μs. In some implementations, L-LTF 606 may include LTF information, which includes a cyclic prefix 605, OFDM symbol C1 607, and OFDM symbol C2 609. The LTF information can be transmitted within 8 μs, as shown in the diagram. Figure 6 As shown in the image.

[0060] In listen mode, STA 201 can switch between monitoring the radio channel to search for PPDU 600 and not monitoring the radio channel. Operations for monitoring the radio channel may include at least one radio and data path stabilization operation. The radio and data path stabilization operation can power on the RF front end (such as RF front end 406) after a power-down state. The radio and data path stabilization operation can also allow the radio and data paths in the RF front end to stabilize and be ready to perform additional operations for monitoring the radio channel. Monitoring operations may also include at least one autocorrelation operation (such as detecting repetition of STF information included in L-STF 604) for detecting L-STF 604 of PPDU 600. Operations for not monitoring the radio channel may include operations for configuring the packet detection component to a power-down state. In listen mode, STA 201 can switch between monitoring and not monitoring the radio channel until a packet preamble, such as L-STF 604 of packet preamble 602, is detected. If STA 201 detects L-STF 604, STA 201 can perform operations to prepare for processing L-LTF 606. In some implementations, these operations may include gain-changing operations and coarse timing operations. Gain-changing operations can change the gain of an amplifier in the RF front-end (such as RFA416) to improve the strength or amplitude of the received signal associated with PPDU 600 for further processing. Coarse timing operations can occur after the gain-changing operations. Coarse timing operations can adjust the coarse timing of the RF front-end 406 to align the frame with the symbol boundaries of L-LTF 606.

[0061] like Figure 6 As shown, example operation sequence 620 may include operations for a listening mode. Operation sequence 620 may begin with operations for monitoring the radio channel to locate PPDU 600. For example, operation sequence 620 may begin with a first radio and data path stabilization operation 610 and a first autocorrelation operation 612. In some implementations, STA 201 may detect L-STF 604 if the autocorrelation operation (such as the first autocorrelation operation 612) begins after L-STF 604 is received. Figure 6 In the example shown, timing line 630 instructs STA 201 to begin the first autocorrelation operation 612 before receiving L-STF 604. Therefore, in Figure 6In the example shown, STA 201 does not detect L-STF 604. Operation sequence 620 can continue the operation of STA 201 stopping monitoring of the radio channel. For example, operation sequence 620 can perform a power-off operation 618 to stop monitoring the radio channel. After power-off operation 618, STA 201 can resume monitoring the radio channel. For example, STA 201 can perform a second radio and data path stabilization operation 611 and a second autocorrelation operation 613. In operation sequence 620, STA 201 can detect L-STF 604 by performing the second autocorrelation operation 613 after receiving L-STF 604. In some implementations, the second autocorrelation operation 613 can detect two repetitions of STF information in L-STF 604. After detecting L-STF 604, STA 201 can perform operations to prepare for processing L-LTF 606. In operation sequence 620, STA 201 may perform gain change operation 614 and coarse timing operation 616 to prepare for processing L-LTF 606. After preparing L-LTF 606, STA 201 may switch to receive mode. In receive mode, STA 201 may perform the remaining operations for processing L-LTF 606 and PPDU 600.

[0062] The operation of the listen mode and receive mode can have associated power states. When monitoring the wireless channel in listen mode, the power state controller 404 of STA 201 can configure the packet detection component to a power-on state. When STA 201 stops monitoring the wireless channel, the power state controller 404 can configure the packet detection component to a power-off state. Figure 6As shown in the example power graph 608, the power states associated with operations performed in listen mode and receive mode are illustrated. As shown in operation sequence 620, listen mode may include a first radio and data path stabilization operation 610. Power state controller 404 may provide power to the packet detection packet to enter a power-on state to perform the first radio and data path stabilization operation 610, as shown in power graph 608. Power state controller 404 may keep the packet detection component in the power-on state for a continuous first autocorrelation operation 612, as shown in power graph 608. After monitoring the radio channel, STA 201 may stop monitoring the radio channel. To stop monitoring the radio channel, power state controller 404 may perform a power-off operation 618. For power-off operation 618, power state controller 404 may stop providing power to the packet detection component to enter a power-off state, as shown in power graph 608. STA 201 may resume monitoring the radio channel by performing a second radio and data path stabilization operation 611. For the second radio and data path stabilization operation 611, the power state controller 404 can provide power to the packet detection component to enter a power-on state. The power state controller 404 can keep the packet detection component in the power-on state while continuously performing the second autocorrelation operation 613, gain change operation 614, and coarse timing operation 616, as shown in the power graph 608. As shown in the power graph 608, the packet detection component can remain in the power-on state throughout the receive mode.

[0063] Operations in monitoring mode may involve timing aspects related to the PPDU. For example, the PPDU may have one or more transmission times defined in the IEEE 802.11 standard. Figure 6 As shown, the L-STF 604 can be transmitted within 8 μs. In some implementations, the L-STF 604 can be detected within 8 μs during listen-mode operation. Listen-mode operation may include operations for monitoring the radio channel, not monitoring the radio channel, and preparing the L-LTF. Figure 6 As shown, the operation for monitoring the wireless channel may include a first radio and data path stabilization operation 610 and a first autocorrelation operation 612. In some implementations, the first radio and data path stabilization operation 610 may have a duration of 1.2 μs, and the first autocorrelation operation 612 may have a duration of 1.6 μs. Therefore, the duration for monitoring the wireless channel may be 2.8 μs (1.2 μs + 1.6 μs). Figure 6As shown, STA 201 can stop monitoring the wireless channel by performing a power-off operation 618. In some implementations, STA 201 can stop monitoring the wireless channel for up to 2.4 μs, as shown in operation sequence 620. Therefore, the duration of both monitoring and not monitoring the wireless channel can be 5.2 μs (2.4 μs + 2.8 μs). In this example, the duty cycle for the listening mode can be 46% (2.4 / 5.2). In some implementations, after detecting L-STF 604, STA 201 can perform operations to prepare for processing L-LTF 606. For example, STA 201 can perform a gain change operation 614 and a coarse timing operation 616 to prepare for processing L-LTF 606. In some implementations, the gain change operation 614 can have a duration of 1.2 μs, and the coarse timing operation 616 can have a duration of 1.6 μs, as shown in operation sequence 620. Therefore, the operation for preparing the L-LTF 606 can have a duration of 2.8 μs (1.2 μs + 1.6 μs). The total duration for monitoring (2.8 μs), not monitoring (2.4 μs), and preparing the L-LTF 606 (2.8 μs) can be 8 μs (2.8 μs + 2.4 μs + 2.8 μs = 8 μs). Since the total duration of the monitoring mode operation is 8 μs, the STA 201 can detect the L-STF 604 within its 8 μs transmission time.

[0064] Another timing aspect of the monitoring mode involves detecting L-STFs while monitoring the wireless channel. In some implementations, the STA201 can perform autocorrelation operations to detect L-STFs, such as by detecting repetitions of STF information associated with the L-STF. A detection duration may exist for detecting a portion of the STF information via autocorrelation. The detection duration can indicate how late the autocorrelation operation can proceed while the L-STF can be received and still detected. Figure 6 As shown, STA 201 may have a detection duration of 625 for detecting a portion of L-STF 604 (such as a repeating portion of STF information). In some implementations, the detection duration 625 may be 0.4 μs. Figure 6 In this context, arrival deadline 624 indicates the latest time that L-STF 604 can arrive and be detected by the first autocorrelation operation 612. Figure 6In the diagram, timing line 630 shows that L-STF 604 arrives after arrival deadline 624, therefore L-STF 604 is not detected. If L-STF 604 arrives before arrival deadline 624, STA 201 may have already detected L-STF 604. In some implementations, the detection duration 625 can affect how long STA 201 stops monitoring the wireless channel. For example, if the detection duration 625 is long, the duration of power-down operation 618 can be shortened to ensure that STA 201 can detect L-STF 604 within 8 μs.

[0065] Another timing aspect of the listener mode involves coarse timing. In some implementations, the STA 201 can perform coarse timing operations to prepare for processing L-LTF. For example, as... Figure 6 As shown, STA 201 can perform a coarse timing operation 616 to prepare for processing L-LTF 606. The coarse timing deadline indicates the latest time by which STA 201 can complete the coarse timing operation and still be ready to process the L-LTF. If the coarse timing operation is not completed before the coarse timing deadline, STA 201 may be unable to process the L-LTF. Figure 6 As shown, timing line 627 indicates when STA 201 receives L-STF 606. Coarse timing period 626 indicates the latest time STA 201 can complete coarse timing operation 616 and still process L-LTF 606. In some implementations, the coarse timing period can be 0.4 μs after receiving the L-LTF. In some implementations, the coarse timing period can affect how long STA 201 can stop monitoring the wireless channel. For example, if the coarse timing period 626 is short, the duration of power-down operation 618 can be shortened to ensure that STA 201 can detect L-STF 604 within 8 μs.

[0066] In some implementations, STA 201 may reduce the time spent in the power-on state during monitoring mode. For example, STA 201 reduces the time spent monitoring the wireless channel during the power-on state. Operations for monitoring the wireless channel may include radio and data path stabilization operations (such as radio and data path stabilization operation 610) and autocorrelation operations (such as first autocorrelation operation 612). In some implementations, the autocorrelation operation may be replaced by a matched filtering operation. For example, instead of using autocorrelation to detect L-STF, STA 201 may use matched filtering to detect L-STF. The matched filtering operation may use pattern matching to detect L-STF. For example, the matched filtering operation may detect L-STF by using pattern matching to detect a single repetition of STF information. In some implementations, the matched filtering operation may have a duration of 1 μs (compared to 1.6 μs for some implementations of the autocorrelation operation). In some implementations, STA 201 may monitor the wireless channel by performing both radio and data path stabilization operations and matched filtering operations. The combined duration of the match filtering operation (1 μs) and the radio and data path stabilization operation (1.2 μs) can be 2.2 μs. Therefore, the duration for monitoring the wireless channel can be 2.2 μs.

[0067] In some implementations, STA 201 can also use a 1μs matched filtering operation to perform coarse timing operations (such as coarse timing operation 616). When STA 201 uses the 1μs matched filtering operation for coarse timing operations (such as operation 616), STA 201 can stop monitoring the wireless channel for up to 3.6μs. Therefore, the total duration of the operation for both monitoring and not monitoring the wireless channel can be 5.8μs (3.6μs + 2.2μs). In this example, the duty cycle for the listening mode can be 62% (3.6 / 5.8).

[0068] In some implementations, the packet may include an L-STF of any duration. For example, the packet may include an undeveloped preamble with an L-STF longer than 8 μs. Undeveloped preambles are defined in the IEEE 802.11be standard. In some implementations, the undeveloped preamble may include an L-STF with a duration of 10 μs or longer. In some implementations, the STA 201 may perform operations for up to 2.2 μs in the power-on state, as in... Figure 6 As described in the text. Given a 10 μs L-STF and a 2.2 μs power-on state operation, the STA can remain in the power-off state for up to 3.6 μs and until L-STF 604 is detected within 10 μs. Given a 10 μs L-STF and Figure 6 The timing of the power-on operation shown in the figure allows STA 201 to achieve a duty cycle of 62%. In some implementations, the duty cycle may depend at least in part on the duration of the L-STF and the operating speed used to detect the L-STF.

[0069] Figure 7 A process 700 for wireless communication in a WLAN is described, including example operations performed by a device of a STA. Process 700 can be performed by wireless communication devices (such as those described in reference 1). Figure 8 and 10 The described wireless communication device 800 or electronic device 1000 may perform this process. In some implementations, process 700 may be performed by a STA (such as reference STA). Figure 1 , 2 3 and Figure 9B The wireless communication device that operates or operates within the STA (one of the STAs described) is used to perform this function.

[0070] In block 710, the means of the first WLAN device can cause one or more components of the first WLAN device to alternate between a power-off state and a power-on state during the listening mode of the first WLAN device.

[0071] In box 720, the device can receive preamble information from a second WLAN device during the power-on state.

[0072] Figure 8 A block diagram of an example wireless communication device 800 is shown. In some implementations, wireless communication device 800 may be an example of a device for use in a STA (such as one of STA 104 or STA 201 described herein). In some implementations, wireless communication device 800 may be an example of a device for use in an AP (such as AP 102 described herein). Wireless communication device 800 may generally be referred to as a device or wireless communication apparatus. Wireless communication device 800 is capable of transmitting (or outputting for transmission) and receiving wireless communications (e.g., in the form of wireless packets). For example, wireless communication device 800 may be configured to transmit and receive packets in the form of PPDUs and MPDUs conforming to IEEE 802.11 standards (such as those defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be in addition to future 802.11 standards).

[0073] The wireless communication device 800 may be or may include a chip, system-on-a-chip (SoC), chipset, package, or device that includes one or more modems 802 (e.g., a Wi-Fi (IEEE 802.11 compliant) modem). In some implementations, the one or more modems 802 (collectively referred to as "Modem 802") additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compliant modem). In some implementations, the wireless communication device 800 also includes one or more radios 804 (collectively referred to as "Radio 804"). In some implementations, the wireless communication device 800 further includes one or more processors, processing blocks, or processing elements (collectively referred to as "Processor 806") and one or more memory blocks or elements (collectively referred to as "Memory 808").

[0074] Modem 802 may include intelligent hardware blocks or devices (e.g., application-specific integrated circuits (ASICs)). Modem 802 is generally configured to implement a PHY layer. For example, modem 802 is configured to modulate packets and output modulated packets to radio 804 for transmission over a wireless medium. Similarly, modem 802 is configured to receive modulated packets received by radio 804 and demodulate these packets to provide demodulated packets. In addition to modulators and demodulators, modem 802 may further include digital signal processing (DSP) circuitry, automatic gain control (AGC), encoders, decoders, multiplexers, and demultiplexers. For example, when in transmit mode, data obtained from processor 806 is provided to an encoder, which encodes the data to provide coded bits. The coded bits are mapped to points in a modulation constellation (using a selected MCS) to provide modulated symbols. The modulated symbols may be mapped to several (N) points. SS One) spatial flow or several (N) STS (Number) space-time streams. Modulated symbols in the corresponding spatial or space-time streams can be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and subsequently provided to the DSP circuitry for Tx windowing and filtering. The digital signal can be provided to a digital-to-analog converter (DAC). The resulting analog signal can be provided to an up-converter and ultimately to a radio 804. In implementations involving beamforming, the modulated symbols in the corresponding spatial streams are pre-coded via a guiding matrix before being provided to the IFFT block.

[0075] When in receive mode, the digital signal received from radio 804 is provided to a DSP circuitry system configured to acquire the received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offset. The DSP circuitry system is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry system can be fed to an AGC, which is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine the appropriate gain. The output of the DSP circuitry system is also coupled to a demodulator configured to extract modulated symbols from the signal and, for example, calculate the log-likelihood ratio (LLR) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled to a decoder configured to process the LLR to provide decoded bits. The decoded bits from all spatial streams are fed to a demultiplexer for demultiplexing. Demultiplexed bits can be descrambled and provided to the MAC layer (processor 806) for processing, evaluation, or interpretation.

[0076] Radio 804 generally includes at least one radio frequency (RF) transmitter (or “transmitter chain”) and at least one RF receiver (or “receiver chain”), which can be combined into one or more transceivers. For example, the RF transmitter and receiver may include various DSP circuitry systems, each including at least one power amplifier (PA) and at least one low-noise amplifier (LNA). The RF transmitter and receiver may then be coupled to one or more antennas. For example, in some implementations, wireless communication device 800 may include or be coupled to multiple transmitting antennas (each with a corresponding transmitting chain) and multiple receiving antennas (each with a corresponding receiving chain). Symbols output from modem 802 are provided to radio 804, which transmits the symbols via the coupled antennas. Similarly, symbols received via the antennas are acquired by radio 804, which provides the symbols to modem 802. In some implementations, radio 804 and one or more antennas may form one or more network interfaces (which may also be referred to as “interfaces”).

[0077] Processor 806 may include intelligent hardware blocks or devices designed to perform the functions described herein, such as, for example, processing cores, processing blocks, central processing units (CPUs), microprocessors, microcontrollers, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable logic devices (PLDs) (such as field-programmable gate arrays (FPGAs)), discrete gate or transistor logic, discrete hardware components, or any combination thereof. Processor 806 processes information received via radio 804 and modem 802, and processes information to be output via modem 802 and radio 804 for transmission over a wireless medium. For example, processor 806 may implement a control plane and a MAC layer, configured to perform various operations related to the generation and transmission of MPDUs, frames, or packets. The MAC layer is configured to perform or facilitate frame encoding and decoding, spatial multiplexing, space-time block decoding (STBC), beamforming, and OFDMA resource allocation, and other operations or techniques. In some implementations, processor 806 may generally control modem 802 to cause the modem to perform the various operations described above.

[0078] Memory 808 may include tangible storage media, such as random access memory (RAM) or read-only memory (ROM), or combinations thereof. Memory 808 may also store non-transient processor or computer-executable software (SW) code containing instructions that, when executed by processor 806, cause the processor to perform various operations described herein for wireless communication, including the generation, transmission, reception, and interpretation of MPDUs, frames, or packets. For example, the various functions of the components disclosed herein, or the various blocks or steps of the methods, operations, processes, or algorithms disclosed herein, may be implemented as one or more modules of one or more computer programs.

[0079] In some implementations, the wireless communication device 800 may include a power state controller (not shown). The power state controller may be similar to reference [reference needed]. Figure 4 The power state controller 404 is described and can implement any of the operations described herein for controlling power. In some implementations, the power state controller may be implemented by a processor 806 and a memory 808. The memory 808 may include computer instructions executable by the processor 806 to implement the functionality of the power state controller. Any of these functionalities may be implemented partially (or entirely) in hardware or on the processor 806.

[0080] In some implementations, the processor 806 and memory 808 of the wireless communication device 800 may be referred to as a processing system. A processing system generally refers to a system or series of machines or components that receive inputs and process those inputs to produce a set of outputs (which can be passed to other systems or, for example, one of the STA 104 or one of the AP 102). In some implementations, the processing system may include the processor 806, the memory 808, and one or more other components of the wireless communication device 800 (such as a modem 802).

[0081] In some implementations, the processing system of STA 104 can interface with other components of STA 104 and can process information (such as inputs or signals) received from other components, output information to other components, etc. For example, the chip or modem of STA 104 (such as wireless communication device 800) may include a processing system and one or more interfaces. These one or more interfaces may include: a first interface for receiving or acquiring information, and a second interface for outputting, transmitting, or providing information. In some cases, the first interface may refer to the interface between the processing system of the chip or modem and the receiver, allowing STA 104 to receive information or signal input, and information to be transmitted to the processing system. In some cases, the second interface may refer to the interface between the processing system of the chip or modem and the transmitter, allowing STA 104 to transmit information output from the chip or modem. Those skilled in the art will readily recognize that the second interface may also acquire or receive information or signal input, and the first interface may also output, transmit, or provide information.

[0082] In some implementations, the processing system of AP 102 can interface with other components of AP 102 and can process information (such as inputs or signals) received from other components, output information to other components, etc. For example, the chip or modem of AP 102 (such as wireless communication device 800) may include a processing system, a first interface for receiving or acquiring information, and a second interface for outputting, transmitting, or providing information. In some cases, the first interface may refer to the interface between the processing system of the chip or modem and the receiver, allowing AP 102 to receive information or signal input, and information can be transmitted to the processing system. In some cases, the first interface may refer to the interface between the processing system of the chip or modem and the transmitter, allowing AP 102 to transmit information output from the chip or modem. Those skilled in the art will readily recognize that the second interface can also acquire or receive information or signal input, and the first interface can also output, transmit, or provide information.

[0083] Figure 9AA block diagram of an example AP 902 is shown. For example, AP 902 could be an example implementation of the AP 102 described herein. AP 902 includes a wireless communication device 910. For example, wireless communication device 910 could be a reference... Figure 8 An example implementation of the described wireless communication device 800 is described. AP 902 also includes a plurality of antennas 920 coupled to the wireless communication device 910 for transmitting and receiving wireless communications. In some implementations, AP 902 additionally includes an application processor 930 coupled to the wireless communication device 910, and a memory 940 coupled to the application processor 930. AP 902 further includes at least one external network interface 950, which enables AP 902 to communicate with a core network or backhaul network to obtain access to external networks, including the Internet. For example, external network interface 950 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Components of the foregoing can communicate directly or indirectly with other components of these components on at least one bus. AP 902 further includes a housing that encloses the wireless communication device 910, the application processor 930, the memory 940, and at least portions of the antennas 920 and the external network interface 950.

[0084] Figure 9B A block diagram of an example STA 904 is shown. For example, STA 904 could be an example implementation of STA 104 or STA 201 described herein. STA 904 includes a wireless communication device 915. For example, wireless communication device 915 could be a reference device. Figure 8 An example implementation of the described wireless communication device 800. STA 904 may also include one or more antennas 925 coupled to the wireless communication device 915 for transmitting and receiving wireless communications. STA 904 additionally includes an application processor 935 coupled to the wireless communication device 915, and a memory 945 coupled to the application processor 935. In some implementations, STA 904 further includes a user interface (UI) 955 (such as a touchscreen or keyboard) and a display 965, which may be integrated with the UI 955 to form a touchscreen display. In some implementations, STA 904 may further include one or more sensors 975 (such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors). Components of the foregoing components may communicate directly or indirectly with other components of these components on at least one bus. STA 904 further includes a housing that encloses the wireless communication device 915, the application processor 935, the memory 945, and at least portions of the antenna 925, the UI 955, and the display 965.

[0085] Figure 10 A block diagram of an example electronic device for implementing various aspects of this disclosure is shown. In some implementations, electronic device 1000 may be an AP (including any AP described herein), a range extender, a station (including any of the STAs described herein), or another electronic system. Electronic device 1000 may include processor 1002 (potentially including multiple processors, multiple cores, multiple nodes, or implementing multithreading, etc.). Electronic device 1000 may also include memory 1006. Memory 1006 may be system memory or any of the possible implementations of the computer-readable medium described herein. In some implementations, processor 1002 and memory 1006 may be referred to as a processing system. Electronic device 1000 may also include bus 1010 (such as PCI, ISA, PCI-Express, etc.). AHB, AXI, etc.) and one or more network interfaces 1004 (which may also be referred to as "interfaces"), the one or more network interfaces 1004 including wireless network interfaces (such as WLAN interfaces, interface, interface, The electronic device 1000 may have at least one of a network interface (such as a wireless USB interface, etc.) and a wired network interface (such as an Ethernet interface, a power line communication interface, etc.). In some implementations, the electronic device 1000 may support multiple network interfaces, each of which is configured to couple the electronic device 1000 to a different communication network.

[0086] Electronic device 1000 may include a power state controller 404 that implements the operations for controlling power as described herein. In some implementations, the power state controller 404 may be distributed within processor 1002 and memory 1006. The power state controller 404 may perform some or all of the location-aware boot operations described herein. In some implementations, network interface 1004 may include RF front end 406, ADC 408, and baseband processing unit 410. In some implementations, the network interface may also include power state controller 404.

[0087] Memory 1006 may include computer instructions that can be executed by processor 1002 to implement... Figure 1-10 The functionality of each implementation described herein. Any of these functionalities may be implemented partially (or entirely) in hardware or on processor 1002. For example, the functionality may be implemented using an application-specific integrated circuit, in logic implemented in processor 1002, in a coprocessor on a peripheral device or card, etc. Furthermore, each implementation may include fewer components or include Figure 10Additional components not described herein (such as video cards, audio cards, additional network interfaces, peripheral devices, etc.). Processor 1002, memory 1006, and network interface 1004 are coupled to bus 1010. Although described as being coupled to bus 1010, memory 1006 may also be coupled to processor 1002.

[0088] Figure 1-10 The operations described herein are examples intended to aid in understanding the exemplary implementations and should not be used to limit potential implementations or the scope of the claims. Some implementations may perform additional operations, perform fewer operations, perform operations in parallel or in a different order, or perform some operations differently.

[0089] The foregoing disclosure provides explanations and descriptions, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the foregoing disclosure or may be obtained through practice of the aspects. While aspects of this disclosure have been described by way of various examples, any combination of aspects from any of these examples is also within the scope of this disclosure. The examples in this disclosure are provided for illustrative purposes. As a replacement or supplement to the other examples described herein, the examples include any combination of the following implementation options.

[0090] Clause 1. An inventive aspect of the subject matter described in this disclosure can be implemented in a method for wireless communication in a WLAN, performed by a device of a first AP. The method may include causing one or more components of the first WLAN device to alternate between a power-off state and a power-on state during a listening mode of the first WLAN device. The method may include receiving preamble information of packets from a second WLAN device during the power-on state.

[0091] Clause 2, the method of Clause 1, further includes performing autocorrelation on the preamble information to detect the preamble of the group.

[0092] Clause 3. The method of any one or more of Clauses 1-2, wherein the first WLAN device remains in a power-on state to perform autocorrelation on preamble information. The method further includes: in response to detecting a preamble of a packet based on autocorrelation, causing one or more components of the WLAN device to stop alternating between a power-off mode and a power-on mode during a listening mode. The method further includes initiating a receive mode for processing packets.

[0093] Clause 4. The method of any one or more of Clauses 1-3, wherein the preamble of the group comprises several repetitions of the preamble information. The method further comprises detecting the preamble information by detecting one or more repetitions of the preamble information.

[0094] Clause 5, any one or more of the methods in Clauses 1-4, wherein the multiple repetitions of the preamble information include the multiple repetitions of the STF information.

[0095] Clause 6. The method of any one or more of Clauses 1-5, wherein the duration of the power-off state and the duration of the power-on state are based at least in part on the number of repetitions of the preamble information and the duration of the preamble used for detecting the packet.

[0096] Clause 7. The method of any one or more of Clauses 1-6, wherein alternating one or more components between a power-off state and a power-on state comprises alternating one or more components between a power-off state and a power-on state according to a duty cycle.

[0097] Clause 8. The method of any one or more of Clauses 1-7, wherein one or more components of the first WLAN device alternate between a power-off state and a power-on state when the RSSI is greater than the RSSI threshold.

[0098] Clause 9. The method of any one or more of Clauses 1-8, wherein one or more components of the first WLAN device alternate between a power-off state and a power-on state when the RSSI is greater than a first RSSI threshold and less than a second RSSI threshold.

[0099] Clause 10. The method of any one or more of Clauses 1-9, wherein one or more components of the first WLAN device include at least one of the following: one or more components of the RF front end, the ADC, and one or more components of the baseband processing unit.

[0100] Clause 11, the method of any one or more of Clauses 1-10, further includes performing matching filtering on the preamble information to detect the preamble of the group.

[0101] Clause 12, the method of any one or more of Clauses 1-11, wherein the first WLAN device remains powered on to perform matching filtering on the preamble of packets.

[0102] Clause 13. Another inventive aspect of the subject matter described in this disclosure can be implemented in an apparatus of a first WLAN device for wireless communication. The apparatus of the first WLAN device may include a processor configured to cause one or more components of the first WLAN device to alternate between a power-off state and a power-on state during a listening mode of the first WLAN device. The apparatus of the first WLAN device may include an interface configured to obtain preamble information of packets from a second WLAN device during the power-on state.

[0103] Clause 14, the apparatus of Clause 13, wherein the processor is further configured to perform autocorrelation on the preamble information to detect the preamble of the block.

[0104] Clause 15. An apparatus of any one or more of Clauses 13-14, wherein the processor is further configured to: in response to detecting a preamble of a packet based on autocorrelation, cause one or more components of the first WLAN device to stop alternating between a power-off state and a power-on state during a listening mode. The processor may be further configured to begin a receiving mode for processing packets.

[0105] Clause 16. An apparatus of any one or more of Clauses 13-15, wherein the preamble of a block comprises several repetitions of preamble information, and wherein detecting the preamble comprises detecting one or more repetitions of the preamble information.

[0106] Clause 17. A device of any one or more of Clauses 13-16, wherein the repetitions of the preamble information include the repetitions of the STF information.

[0107] Clause 18. The apparatus of any one or more of Clauses 13-17, wherein the duration of the power-off state and the duration of the power-on state are based at least in part on the number of repetitions of the preamble information and the duration of the preamble used for detecting the packet.

[0108] Clause 19. A device of any one or more of Clauses 13-18, wherein alternating one or more components between a power-off state and a power-on state comprises alternating one or more components between a power-off state and a power-on state according to a duty cycle.

[0109] Clause 20, an apparatus of any one or more of Clauses 13-19, wherein the interface is further configured to: obtain RSSI associated with a packet, wherein one or more components of the first WLAN device alternately respond to an RSSI greater than an RSSI threshold between a power-off state and a power-on state.

[0110] Clause 21, an apparatus of any one or more of Clauses 13-20, wherein the interface is further configured to: obtain RSSI associated with a packet, wherein one or more components of the first WLAN device alternately respond to an RSSI greater than a first RSSI threshold and less than a second RSSI threshold between a power-off state and a power-on state.

[0111] Clause 22. An apparatus of any one or more of Clauses 13-21, wherein one or more components of the first WLAN device include at least one of the following: one or more components of the RF front end, the ADC, and one or more components of the baseband processing unit.

[0112] Clause 23, an apparatus of any one or more of Clauses 13-22, wherein the processor is further configured to perform match filtering on one or more fields of the preamble information to detect the preamble of the group.

[0113] Clause 24. Another inventive aspect of the subject matter described in this disclosure can be implemented in a non-transient computer-readable medium storing instructions that, when executed by a processor of a first WLAN device, cause the first WLAN device to perform operations for communication in the WLAN. These operations enable the first WLAN device to: cause one or more components of the first WLAN device to alternate between a power-off state and a power-on state during the first WLAN device's listening mode. These operations enable the first WLAN device to: obtain preamble information of packets from a second WLAN device during the power-on state.

[0114] Clause 25, a non-transient computer-readable medium such as any one or more of Clauses 1-12 and 24, wherein these instructions further cause the first WLAN device to perform autocorrelation on preamble information to detect the preamble of a packet.

[0115] Clause 26. A non-transient computer-readable medium such as any one or more of Clauses 1-12 and 24-25, wherein the first WLAN device remains in a power-on state to perform autocorrelation on preamble information. These instructions further cause the first WLAN device to: in response to detecting a preamble of a packet based on autocorrelation, cause one or more components of the WLAN device to stop alternating between a power-off mode and a power-on mode during a listening mode; and begin a receiving mode to process packets.

[0116] Clause 27. A non-transient computer-readable medium such as any one or more of Clauses 1-12 and 24-26, wherein the preamble information comprises several repetitions of symbols. These instructions further enable the first WLAN device to detect the preamble information by detecting one or more repetitions of symbols.

[0117] Clause 28. Another inventive aspect of the subject matter described in this disclosure can be implemented in the apparatus of a first WLAN device for wireless communication. The apparatus of the first WLAN device may include means for alternating one or more components of the first WLAN device between a power-off state and a power-on state during a listening mode of the first WLAN device. The apparatus of the first WLAN device may include means for obtaining preamble information of packets from a second WLAN device during the power-on state.

[0118] Clause 29, the apparatus of any one or more of Clauses 1-12 and 28, further includes means for performing autocorrelation on preamble information to detect preamble of a packet.

[0119] Clause 30, an apparatus of any one or more of Clauses 1-12 and 28-29, wherein the first WLAN device remains in a power-on state to perform autocorrelation on preamble information. The apparatus further includes means for performing the following operations: in response to detecting a preamble of a packet based on autocorrelation, stopping one or more components of the WLAN device from alternating between a power-off mode and a power-on mode during a listening mode; and initiating a receive mode for processing packets.

[0120] Another inventive aspect of the subject matter described in this disclosure can be implemented as an apparatus for a station or access point for wireless communication. The apparatus may include one or more interfaces and one or more processors configured to perform any of the methods or features described herein.

[0121] As used in this article, the phrase “at least one of” a list of items refers to any combination of those items, including a single member. As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc.

[0122] The various descriptive logics, logic blocks, modules, circuits, and algorithmic processes described in conjunction with the implementations disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. Hardware-software interchangeability has been generally described in terms of its functionality and is explained throughout the various descriptive components, blocks, modules, circuits, and processes described herein. Whether such functionality is implemented in hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0123] Hardware and data processing apparatuses for implementing the various descriptive logics, logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or executed using general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration. In some implementations, specific processes and methods may be executed by a circuit system dedicated to a given function.

[0124] In one or more aspects, the described functionality may be implemented in hardware, digital electronic circuit systems, computer software, firmware (including the structures disclosed herein and their structural equivalents), or any combination thereof. Implementation of the subject matter described herein may also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium for execution by a data processing apparatus or for controlling the operation of a data processing apparatus.

[0125] If implemented in software, the functions can be stored or transmitted as one or more instructions or codes on or through a computer-readable medium. The processes of the methods or algorithms disclosed herein can be implemented in a processor-executable software module that can reside on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium that can be implemented to transfer a computer program from one location to another. Storage media can be any available medium accessible to a computer. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection can also be properly referred to as a computer-readable medium. Disks and discs as used herein include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. TM Disks, where disks typically reproduce data magnetically, and discs reproduce data optically using lasers. Combinations can also be included within the scope of computer-readable media. Additionally, the operation of a method or algorithm may reside as one of code and instructions, or any combination or set of code and instructions, on machine-readable and computer-readable media that can be incorporated into a computer program product.

[0126] Various modifications to the implementations described in this disclosure may be apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Therefore, the claims are not intended to be limited to the implementations shown herein, but are to be granted the broadest scope consistent with this disclosure, the principles disclosed herein, and the novel features.

[0127] In addition, those skilled in the art will readily appreciate that the terms “upper” and “lower” are sometimes used for the convenience of describing the figures and indicate a relative position corresponding to the orientation of the figures on the correctly oriented page, and may not reflect the true orientation of any device as implemented.

[0128] Some features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately or in any suitable sub-combination in multiple implementations. Furthermore, although features may be described as operating in certain combinations and even originally claimed in this way, one or more features from the claimed combination may be removed from that combination in some cases, and the claimed combination may be for sub-combinations or variations thereof.

[0129] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order shown or sequentially, or requiring the performance of all explained operations to achieve the desired result. Furthermore, the drawings may schematically depict one or more example processes in the form of flowcharts. However, other operations not depicted may be incorporated into the schematically explained example processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any explained operation. In some environments, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the described implementation should not be construed as requiring such separation in all implementations, 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. Additionally, other implementations also fall within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result.

Claims

1. A method for wireless communication by a first wireless local area network (WLAN) device for wireless communication in a WLAN, comprising: causing one or more components of the first WLAN device to alternate between a power down state of a listen mode of the first WLAN device and a power up state of the listen mode according to a duty cycle upon receiving a received signal strength indicator (RSSI) being greater than an RSSI threshold; cycling, by the first WLAN device, between the listen mode, a receive mode, and a sleep mode, wherein no power is supplied to a packet detection component of the first WLAN device during the sleep mode; and receiving preamble information included in a preamble of a packet from a second WLAN device during the power up state of the listen mode.

2. The method of claim 1, further comprising: performing an autocorrelation on the preamble information to detect the preamble of the packet.

3. The method of claim 2, wherein the first WLAN device remains in the power up state of the listen mode to perform the autocorrelation on the preamble information, the method further comprising: causing the one or more components of the first WLAN device to stop alternating between the power down state of the listen mode and the power up state of the listen mode and to begin the receive mode for processing the packet in response to detecting the preamble of the packet based on the autocorrelation.

4. The method of claim 1, wherein the preamble of the packet includes a number of repetitions of the preamble information, the method further comprising: detecting the preamble information by detecting one or more repetitions of the preamble information.

5. The method of claim 4, wherein the number of repetitions of the preamble information includes a number of repetitions of short training field (STF) information.

6. The method of claim 4, wherein a duration of the power down state of the listen mode and a duration of the power up state of the listen mode are based at least in part on a number of repetitions of preamble information and a time duration for detecting the preamble of the packet.

7. The method of claim 1, wherein causing the one or more components to alternate between the power down state of the listen mode and the power up state of the listen mode includes causing the one or more components to alternate between the power down state of the listen mode and the power up state of the listen mode according to the duty cycle.

8. The method of claim 1, wherein causing the one or more components of the first WLAN device to alternate between the power down state of the listen mode and the power up state of the listen mode is performed when an RSSI is greater than a first RSSI threshold and less than a second RSSI threshold.

9. The method of claim 1, wherein the one or more components of the first WLAN device include at least one of: one or more components of a radio frequency (RF) front end; an analog to digital converter (ADC); and one or more components of a baseband processing unit.

10. The method of claim 1, further comprising: performing match filtering on the preamble information to detect the preamble of the packet.

11. The method of claim 10, wherein the first WLAN device remains in the powered-on state of the listening mode to perform the match filtering on the preamble information of the packet.

12. An apparatus of a first WLAN device for wireless communication, comprising: a processor configured to: cause one or more components of the first WLAN device to alternate between a powered-off state of a listening mode of the first WLAN device and a powered-on state of the listening mode according to a duty cycle during the listening mode of the first WLAN device when a received channel strength indicator (RSSI) is greater than an RSSI threshold; cycle, by the first WLAN device, between the listening mode, a receive mode, and a sleep mode, wherein no power is supplied to a packet detection component of the first WLAN device during the sleep mode; and an interface configured to obtain preamble information included in a preamble of a packet from a second WLAN device during the powered-on state of the listening mode.

13. The apparatus of claim 12, wherein the processor is further configured to: perform autocorrelation on the preamble information to detect the preamble of the packet.

14. The apparatus of claim 13, wherein the processor is further configured to: cause the one or more components of the first WLAN device to stop alternating between the powered-off state of the listening mode and the powered-on state of the listening mode and start the receive mode to process the packet in response to detecting the preamble of the packet based on the autocorrelation.

15. The apparatus of claim 12, wherein the preamble of the packet includes a number of repetitions of the preamble information, and wherein the processor is further configured to detect the preamble information by detecting one or more repetitions of the preamble information.

16. The apparatus of claim 15, wherein the number of repetitions of the preamble information includes a number of repetitions of short training field (STF) information.

17. The apparatus of claim 15, wherein a duration of the powered-off state of the listening mode and a duration of the powered-on state of the listening mode are based at least in part on a number of repetitions of preamble information and a time duration for detecting the preamble of the packet.

18. The apparatus of claim 12, wherein causing the one or more components to alternate between the powered-off state of the listening mode and the powered-on state of the listening mode comprises causing the one or more components to alternate between the powered-off state of the listening mode and the powered-on state of the listening mode according to the duty cycle.

19. The apparatus of claim 12, wherein the interface is further configured to: ​ obtaining a received signal strength indicator (RSSI) associated with the packet, wherein alternating the one or more components of the first WLAN device between the power down state of the listening mode and the power up state of the listening mode in response to the RSSI being greater than a first RSSI threshold and less than a second RSSI threshold occurs.

20. The apparatus of claim 12, wherein the one or more components of the first WLAN device comprise at least one of: one or more components of a radio frequency (RF) front end; an analog-to-digital converter (ADC); and one or more components of a baseband processing unit.

21. The apparatus of claim 12, wherein the processor is further configured to: perform match filtering on one or more fields of the preamble information to detect a preamble of the packet.

22. The apparatus of claim 21, wherein the processor is further configured to: remain in the power up state of the listening mode to perform the match filtering on the preamble information of the packet.

23. A non-transitory computer-readable medium having instructions stored therein that, when executed by a processor of a first wireless local area network (WLAN) device, cause the first WLAN device to: alternate one or more components of the first WLAN device between a power down state of a listening mode and a power up state of the listening mode according to a duty cycle during the listening mode of the first WLAN device when a received channel strength indicator (RSSI) is greater than an RSSI threshold; cycle, by the first WLAN device, between the listening mode, a receive mode, and a sleep mode, wherein no power is supplied to a packet detection component of the first WLAN device during the sleep mode; and obtain preamble information included in a preamble of a packet from a second WLAN device during the power up state of the listening mode.

24. The non-transitory computer-readable medium of claim 23, wherein the instructions further cause the first WLAN device to: perform autocorrelation on the preamble information to detect the preamble of the packet.

25. The non-transitory computer-readable medium of claim 24, wherein the first WLAN device remains in the power up state of the listening mode to perform the autocorrelation on the preamble information, and wherein the instructions further cause the first WLAN device to: stop alternating the one or more components of the first WLAN device between the power down state of the listening mode and the power up state of the listening mode and begin the receive mode to process the packet in response to detecting the preamble of the packet based on the autocorrelation.

26. The non-transitory computer-readable medium of claim 23, wherein the preamble information comprises a number of repetitions of a symbol, and the instructions further cause the first WLAN device to: detect the preamble information by detecting one or more repetitions of the symbol.

27. An apparatus of a first WLAN device for wireless communication, comprising: means for causing one or more components of the first WLAN device to alternate between a power down state of a listen mode of the first WLAN device and a power up state of the listen mode according to a duty cycle during the listen mode, when a received signal strength indicator (RSSI) is greater than an RSSI threshold; means for cycling, by the first WLAN device, between the listen mode, a receive mode, and a sleep mode, wherein no power is supplied to a packet detection component of the first WLAN device during the sleep mode; and means for obtaining preamble information included in a preamble of a packet from a second WLAN device during the power up state of the listen mode.

28. The apparatus of claim 27, further comprising: means for performing an autocorrelation on the preamble information to detect the preamble of the packet.

29. The apparatus of claim 28, wherein the first WLAN device remains in the power up state of the listen mode to perform the autocorrelation on the preamble information, the apparatus further comprising: means for causing the one or more components of the first WLAN device to cease alternating between the power down state of the listen mode and the power up state of the listen mode, in response to detecting the preamble of the packet based on the autocorrelation, and means for starting the receive mode for processing the packet.

30. The apparatus of claim 27, wherein the preamble of the packet includes a number of repetitions of the preamble information, the apparatus further comprising: means for detecting the preamble information by detecting one or more repetitions of the preamble information.

31. The apparatus of claim 30, wherein the number of repetitions of the preamble information includes a number of repetitions of a short training field (STF) information.

32. The apparatus of claim 30, wherein a duration of the power down state of the listen mode and a duration of the power up state of the listen mode are based at least in part on a number of repetitions of preamble information and a time duration for detecting the preamble of the packet.

33. The apparatus of claim 27, wherein the means for causing the one or more components to alternate between the power down state of the listen mode and the power up state of the listen mode comprises means for causing the one or more components to alternate between the power down state of the listen mode and the power up state of the listen mode according to the duty cycle.

34. The apparatus of claim 27, wherein the means for causing the one or more components of the first WLAN device to alternate between the power down state of the listen mode and the powered up state of the listen mode upon a received signal strength indicator (RSSI) being greater than an RSSI threshold comprises means for causing the one or more components of the first WLAN device to alternate between the power down state of the listen mode and the powered up state of the listen mode upon an RSSI being greater than a first RSSI threshold and less than a second RSSI threshold.

35. The apparatus of claim 27, wherein the one or more components of the first WLAN device comprise at least one of: one or more components of a radio frequency (RF) front end; an analog to digital converter (ADC); and one or more components of a baseband processing unit.

36. The apparatus of claim 27, further comprising: means for performing matched filtering on the preamble information to detect the preamble of the packet.

37. The apparatus of claim 36, wherein the first WLAN device remains in the powered up state of the listen mode to perform the matched filtering on the preamble information of the packet.

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