Power-saving method and communication device

Abstract

A power-saving method for a communication device includes: performing data transmission in an active mode; after the data transmission is completed, entering a radio frequency (RF) sleep mode to periodically alternate between a receive (RX) on state and an RX off state; during the RX on state of the RF sleep mode, performing an idle channel assessment (CCA) detection on an operating channel of the communication device to determine whether the operating channel is idle or busy; and if the operating channel is detected to be busy during the RX on state of the RF sleep mode, switching from the RF sleep mode to an active mode.

Description

[Technical Field]

[0001] The present invention relates to a power-saving method and a communication device, and more specifically, to a power-saving method and a communication device capable of performing a radio frequency (RF) sleep mode. [Previous Technology]

[0002] Unless otherwise stated herein, the methods described in this section do not constitute prior art with respect to the claims listed below, nor are they considered prior art simply because they are included in this section. For battery-powered devices (such as mobile phones), power saving is a key concern. The industry has always focused on reducing power consumption to extend battery life and enhance product competitiveness. In typical Wi-Fi site scenarios, the receive (RX) listening state (used to receive potentially present data packets) consumes a significant amount of power. This occurs even when the site is not actively transmitting or receiving data, resulting in unnecessary power consumption.

[0003] For example, in the current solution, a site might wait for 200 milliseconds during the listening period. This listening period is called the Keep-Alive Time (KAT). The purpose of KAT is to confirm that the access point has no more packets to send, thus allowing the site to enter a power-saving mode. The problem with the current solution is that during the KAT period, the site remains in the RX listening state without actively transmitting or receiving packets, which results in additional power consumption. [Summary of the Invention]

[0004] The following summary is illustrative only and is not intended to be limiting in any way. That is, the following overview is provided to introduce the concepts, key points, benefits, and advantages of the novel and non-obvious techniques described herein. Selected embodiments are further described in the detailed description below. Therefore, the following summary is neither intended to identify the essential features of the claimed subject matter nor to define the scope of the claimed subject matter.

[0005] In one embodiment, a power-saving method for a communication device is disclosed. The power-saving method includes: performing data transmission in an active mode; after the data transmission is completed, entering a radio frequency (RF) sleep mode to periodically alternate between a receive (RX) on state and an RX off state; during the RX on state of the RF sleep mode, performing idle channel assessment (CCA) detection on the operating channel of the communication device to determine whether the operating channel is idle or busy; and if the operating channel is detected to be busy during the RX on state of the RF sleep mode, switching from the RF sleep mode to the active mode.

[0006] In some embodiments, during the RX off state of the RF sleep mode, at least a portion of the RX circuitry of the communication device is in standby mode and / or disabled.

[0007] In some embodiments, the RX circuit of the communication device is enabled during the RF sleep mode RX-on state or during the active mode.

[0008] In some embodiments, entering the RF sleep mode after data transmission is completed includes: determining whether a predetermined condition for entering the RF sleep mode is met after data transmission is completed; and if the predetermined condition is met, entering the RF sleep mode.

[0009] In some embodiments, the method further includes: before entering the RF sleep mode, the communication device sets an RX pause time length to continuously determine the predetermined condition during the RX pause time length.

[0010] In some embodiments, the predetermined condition includes: the communication device does not perform a transmission within a predetermined time;

[0011] The communication device did not perform reception during the predetermined time; and the operation channel was detected as idle during the predetermined time.

[0012] In some embodiments, the predetermined condition further includes: the end time of the predetermined time and the nearest target beacon transmission time (TBTT) exceed a predetermined time threshold.

[0013] In some embodiments, the method further includes: setting a power saving level for the RF sleep mode, wherein the power saving level is set to one of a first power saving level and a second power saving level; wherein when the power saving level is set to the first power saving level, at least a portion of the RX circuits in the communication device are in a standby state in the RX off state of the RF sleep mode, and when the power saving level is set to the second power saving level, at least a portion of the RX circuits in the communication device are in a closed state in the RX off state of the RF sleep mode.

[0014] In some embodiments, when the power saving level is set to the first power saving level, in the RX off state of the RF sleep mode, the physical layer (PHY) circuit is in standby state, the frequency synthesizer (SX) is in enabled state, and at least one antenna is in standby state; while when the power saving level is set to the second power saving level, in the RX off state of the RF sleep mode, the PHY circuit is in standby state, the SX is in disabled state, and at least one antenna is in disabled state.

[0015] In some embodiments, the method further includes: detecting the received signal strength indication (RSSI) of the communication device; detecting the RX transmission amount of the communication device; and, if the RSSI is greater than an RSSI threshold and the RX transmission amount is less than an RX transmission amount threshold, triggering the communication device to enable the RF sleep mode.

[0016] In another embodiment, a communication device is provided, including a radio frequency (RF) transceiver module and a controller, the controller being coupled to the RF transceiver module and configured to control the RF transceiver module to perform operations. The operations include: performing data transmission in an active mode; after data transmission is completed, entering an RF sleep mode to periodically alternate between a receive (RX) on state and an RX off state; during the RX on state of the RF sleep mode, performing an idle channel assessment (CCA) detection on the operating channel of the communication device to determine whether the operating channel is idle or busy; and if the operating channel is detected to be busy during the RX on state of the RF sleep mode, switching from the RF sleep mode to the active mode.

[0017] In some embodiments, during the RX off state of the RF sleep mode, at least a portion of the RX circuitry of the communication device is in standby mode and / or disabled.

[0018] In some embodiments, the RX circuit of the communication device is enabled in the RX-on state of the RF sleep mode or the active mode.

[0019] In some embodiments, after data transmission is completed, the controller determines whether a predetermined condition for entering the RF sleep mode is met. If the predetermined condition is met, the communication device enters the RF sleep mode.

[0020] In some embodiments, the RX pause time length is set before entering the RF sleep mode so that the predetermined condition is continuously determined during the RX pause time length.

[0021] In some embodiments, the predetermined condition includes: the communication device does not perform a transmission within a predetermined time;

[0022] The communication device did not perform reception during the predetermined time; and the operation channel was detected as idle during the predetermined time.

[0023] In some embodiments, the predetermined condition further includes: the end time of the predetermined time and the nearest target beacon transmission time (TBTT) exceed a predetermined time threshold.

[0024] In some embodiments, the power saving level of the RF sleep mode is set to one of a first power saving level and a second power saving level. When the power saving level is set to the first power saving level, at least a portion of the RX circuit of the communication device is in a standby state when the RX is off. When the power saving level is set to the second power saving level, at least a portion of the RX circuit of the communication device is in a closed state when the RX is off.

[0025] In some embodiments, when the power saving level is set to the first power saving level, in the RX off state, the physical layer (PHY) circuit is in standby state, the frequency synthesizer (SX) is in enabled state, and at least one antenna coupled to the RF transceiver module is in standby state. When the power saving level is set to the second power saving level, in the RX off state, the PHY circuit is in standby state, the SX is in disabled state, and at least one antenna coupled to the RF transceiver module is in disabled state.

[0026] In some embodiments, the Received Signal Strength Indication (RSSI) and RX transmission amount of the communication device are detected. If the RSSI is greater than the RSSI threshold and the RX transmission amount is less than the RX transmission amount threshold, the controller triggers the RF transceiver module to enable the function of the RF sleep mode.

[0027] The present invention is provided by way of example and is not intended to be limiting. Other embodiments and advantages are described in the following detailed description. The invention is defined by the claims.

Implementation Method

[0029] The following description illustrates preferred embodiments of the present invention. These embodiments are merely illustrative of the technical features of the invention and are not intended to limit the scope of the invention. Certain terms are used throughout this specification and the claims to refer to specific components. Those skilled in the art will understand that manufacturers may use different terms to refer to the same components. This specification and the claims do not distinguish components by differences in name, but by differences in function. The scope of the invention should be determined with reference to the appended claims. The terms "comprising" and "including" as used in the following description and claims are open-ended terms and should be interpreted as "comprising, but not limited to...". Furthermore, the term "coupled" means an indirect or direct electrical connection. Therefore, if a device is described as coupled to another device, it means that the device can be directly electrically connected to the other device, or indirectly electrically connected to the other device through other devices or connection means. The terms "basically" or "roughly" used in this text refer to a technical problem that can be solved and the desired technical effect achieved by someone with ordinary knowledge in the relevant technical field, within an acceptable range. For example, "roughly equal to" refers to a method that, without affecting the correctness of the result, is acceptable to someone with ordinary knowledge in the relevant technical field, with a certain margin of error compared to "exactly equal to".

[0030] Figure 1 is a timing diagram illustrating the active mode and power-saving mode of a wireless communication device, for example, a Wi-Fi station (STA). Figure 1 shows the device's operating modes and relative power consumption over time. The x-axis represents the timeline, and the y-axis represents the power consumption level of the Wi-Fi module (such as a Wi-Fi chip). Initially, the device is in active mode. During active mode, the device can participate in active data exchange, labeled "traffic" in the figure. Because the transmitter and receiver circuits are enabled in active mode, the power consumption is relatively high.

[0031] After active data flow ceases (i.e., after data transmission is complete), the device enters a "listening" state before transitioning to a low-power saving mode. The device remains in the listening state for a Keep Alive Time (KAT, e.g., 200 milliseconds), during which time the device's receiving circuitry remains enabled (fully powered) and listens for any packets / transmissions that may be sent to it from the associated access point (AP) or other devices. The purpose of setting the KAT is to ensure that no other devices have data they wish to send to the wireless communication device before the site enters power-saving mode. As shown in Figure 1, power consumption remains high during the listening state, comparable to that during data flow interaction, because the receiver needs to be ready to receive potential packets, thus the receiving circuitry remains enabled.

[0032] At the end of the KAT period, if no traffic is detected during the KAT period (i.e., the listening state period), and the wireless communication device decides to switch to power saving mode, the wireless communication device will send a specific signal to the target device (such as an AP). For example, the wireless communication device sends a "null frame" in which the Power Management (PM) bit is set to 1. A null frame with PM=1 can indicate to the target device that the wireless communication device will enter power saving mode. During the transmission of this null frame, there will be a brief peak in power consumption.

[0033] Subsequently, the wireless communication device enters a power-saving mode, which is often referred to as a DTIM (Transmission Traffic Indication Message) mode. In power-saving mode, the wireless communication device significantly reduces power consumption by disabling major parts of its circuitry. For example, the disabled circuitry includes the Microcontroller Unit (MCU), Medium Access Control (MAC) unit, Physical Layer (PHY) circuitry, and Radio Frequency (RF) circuitry. However, the wireless communication device periodically wakes up at predetermined time intervals to listen for beacon frames transmitted by a target device (such as an AP), referred to as a "receive beacon frame" event. For example, the device is periodically woken up at the Target Beacon Transmission Time (TBTT, referring to a predetermined time point for periodically sending beacon frames) to receive periodic beacon frames. Typically, the beacon frame can inform the wireless communication device of the network status and whether the AP has buffered data waiting to be transmitted. This low-power sleep and periodic beacon reception loop will continue as long as the communication device is in power-saving mode and there is no data to transmit / receive.

[0034] In other words, the communication device can interact with the AP (also described as "data flow") in active mode. However, after data transmission is completed, the communication device does not immediately enter power-saving mode, but instead enters a listening / waiting period (e.g., KAT during which it continuously listens) to ensure that the AP has no more data packets to send to the wireless communication device. During the listening period (such as the duration corresponding to KAT), the communication device remains in RX listening state, that is, the communication device can actively listen for any data packets received from the AP. If no more than a predetermined number of data packets are received during the KAT period (e.g., the predetermined number can be set to 2), the communication device will enter power-saving mode to reduce power consumption.

[0035] Figure 2 is a schematic diagram of a communication device 100 according to an embodiment of the present invention. The communication device 100 may be a station (STA) / access point (AP) or any suitable Wi-Fi module. For ease of explanation, an STA is used as an example, but the invention is not limited thereto. The communication device 100 aims to reduce power consumption during Wi-Fi communication (transmission / reception as referred to herein refers to transmission / reception in Wi-Fi communication), and in particular, to reduce power consumption during the receive listening state (RX listening state). In typical Wi-Fi operation, the station consumes a significant amount of power while the device waits to receive potential data during the listening period, even if no data is being transmitted or received. This is because the station needs to keep its receiving function active (i.e., the receiving circuit is enabled / powered) to listen for potential transmissions. The waiting period is also called the keep-alive time (KAT). To further mitigate power consumption (i.e., reduce power consumption during listening), the communication device 100 employs a mechanism / feature called radio frequency (RF) doze mode. During RF sleep mode, communication device 100 dynamically adjusts the activity of its wireless chip (i.e., wireless / WIFI module) by alternating between an RX on state and an RX off state. In other words, during the aforementioned listening period, communication device 100 periodically enters the RX on state to be able to detect and receive data packets / signals, and when necessary (e.g., when channel busy is detected), communication device 100 exits RF sleep mode and re-enters active mode to resume normal operation. By dynamically managing the RX state of the receiving (RX) circuitry of communication device 100, RF sleep mode effectively balances power efficiency and performance. By doing so, communication device 100 is able to reduce power consumption during KAT / listening / waiting periods (e.g., during a predetermined period of time, such as 200 milliseconds, during the transition from active mode to power-saving mode) without sacrificing its ability to receive data.

[0036] In Figure 2, the communication device 100 may include a radio frequency (RF) transceiver module 10a and a controller 10b. The communication device 100 may be an access point (AP) or a station. In some embodiments, the communication device 100 is a battery-powered device capable of managing Wi-Fi power consumption by implementing a mechanism to control the RF sleep mode of its antenna and RX circuitry. For simplicity, the communication device 100 is described in Figure 2 as an example of a station, but the invention is not limited thereto. In the example of Figure 2, the RF transceiver module 10a and the controller 10b may be integrated into a Wi-Fi module (such as wireless chip 10), but this disclosure is not limited thereto. The wireless chip 10 may be a Wi-Fi chip or any chipset capable of enabling wireless (Wi-Fi) communication. The RF transceiver module 10a is used to process the transmission and reception of wireless signals, ensuring that the communication device 100 can effectively transmit and receive data. The controller 10b may be a microcontroller unit (MCU), for example, configured to execute instructions, or, for example, configured to perform calculations required for the operation of the RF transceiver module 10a. For example, controller 10b can control RF transceiver module 10a to execute RF sleep mode to save power and dynamically enable and disable at least one RX function. For example, communication device 100 receives and transmits signals via at least one antenna, and RF transceiver module 10a may include at least one RF path coupled to the antenna and at least one baseband (BB) path coupled to the RF path. The RF path is configured to convert the baseband signal into an RF signal for transmission and vice versa for reception. For example, the RF path may include elements such as a frequency synthesizer (SX), filters, amplifiers, and mixers, wherein the frequency synthesizer (SX) is configured to provide a frequency signal to the mixer for frequency conversion. The baseband path may include components such as an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), and a digital signal processor (DSP). Understandably, the RF transceiver module 10a can be described as including at least a PHY circuit and a frequency synthesizer, wherein the PHY circuit is responsible for handling all functions of the physical layer (PHY), such as signal transmission and reception, modulation and demodulation, encoding, decoding, etc. Understandably, the PHY circuit may include at least a portion of the circuitry in the baseband path and / or RF path described above.

[0037] It should be understood that within the communication device 100, although at least one antenna may be physically located outside the wireless chip 10, the antenna is electrically coupled to the RF transceiver module 10a. Therefore, the power supply for at least one antenna is from or controlled by the RF transceiver module 10a. Thus, subsequent references to placing at least one antenna in a "standby state" or "off mode" should be interpreted as controlling specific circuitry within the RF transceiver module responsible for supplying power to at least one antenna to cause the antenna to enter the corresponding standby or off state. This operation can effectively shut down the antenna or place it in a lower-power standby state by managing the power supply circuitry within the RF transceiver module.

[0038] In Figure 2, since the communication device 100 operates as a station, it communicates with the AP 20. In this embodiment, wireless signals are transmitted from the communication device 100 to the AP 20 and received by the AP 20. In the communication device 100, the controller 10b can control the RF transceiver module 10a to enter an active mode to perform data transmission (e.g., sending / receiving wireless signals / data packets). Then, after the data transmission is completed, the controller 10b can control the RF transceiver module 10a to enter an RF sleep mode by periodically alternating between an RX on state and an RX off state. For example, the RF transceiver module 10a enters the RF sleep mode when predetermined conditions for entering the RF sleep mode are met. Furthermore, the controller 10b can control the RF transceiver module 10a to exit the RF sleep mode and re-enter the active mode. In this embodiment, the RX on state enables the RF transceiver module 10a to receive wireless signals (i.e., the RX function of the RF transceiver module 10a is enabled). In other words, during the period when the communication device 100 is in the RX-on state of RF sleep mode or in active mode (understandably, active mode means that the communication device 100 is always in the RX-on state), the RX circuit of the communication device 100 (e.g., located within the RF transceiver module 10a) is enabled. The RX-off state disables the RF transceiver module 10a from receiving wireless signals (i.e., the RX function of the RF transceiver module 10a is disabled). In other words, during the period when the communication device 100 is in the RX-off state of RF sleep mode, at least a portion of the RX circuit of the communication device 100 (e.g., located within the RF transceiver module 10a) is in a standby state and / or disabled. The RX-off state consumes less power than the RX-on state, but more power than the RX-off state in power-saving mode; therefore, the RF sleep mode can switch to active mode more quickly compared to power-saving mode.

[0039] It should be noted that the RF sleep mode is different from the power saving mode. The power saving mode is a more energy-efficient state than the RF sleep mode, and it occurs after the aforementioned monitoring period, while the RF sleep mode is set specifically for the aforementioned monitoring period. In the power saving mode, the communication device 100 shuts down relevant circuits, including the MCU, MAC unit, PHY circuit, and RF circuit, which efficiently saves power. In contrast, in the RF sleep mode proposed in this invention, when the communication device 100 is in the RX off state of the RF sleep mode, some RX circuits, such as the PHY circuit, remain in standby mode instead of being completely off. The MCU and MAC unit are enabled, and the RF sleep mode can switch to active mode faster than the power saving mode, providing a faster transition back to full operation (RX on state) while still achieving a certain degree of energy saving. Details of the power saving method performed by the communication device 100 are shown below.

[0040] Figure 3 is a schematic diagram of the chip power changes of the communication device 100 in active mode and radio frequency (RF) sleep mode. In Figure 3, the Y-axis represents the chip power level, and the X-axis represents the time line. Initially, the controller 10b activates all functions of the RX circuit within the wireless chip 10, enabling the wireless chip 10 to achieve full data reception capability in active mode. In Figure 3, time point T0 represents the time point when data transmission is completed in active mode, i.e., the start time point of the listening phase. At time point T0, the communication device 100 is fully capable of receiving any incoming data. After time point T0, within the RX pause time length TH (which can also be described as a "predetermined time"), the controller 10b can determine whether the predetermined conditions for entering the RF sleep mode are met. If the predetermined conditions are met, the RF transceiver module 10a enters the RF sleep mode. The RX pause time length TH is set before entering the RF sleep mode to continuously determine the predetermined conditions for entering the RF sleep mode during the RX pause time length. The predetermined conditions may include, but are not limited to: the communication device 100 does not perform transmission during a predetermined time (such as the RX pause time length TH), the communication device 10 does not perform reception during a predetermined time (such as the RX pause time length TH), and the operation channel of the communication device 100 is detected as idle during the predetermined time (such as the RX pause time length TH).

[0041] Specifically, during the RX-on state of the RF sleep mode, a Clear Channel Assessment (CCA) detection is performed on the operating channel. CCA detection determines whether the operating channel is idle or busy. For example, the CCA process involves the communication device sensing an energy level on its designated operating channel. The detected energy level is then compared to a preset energy threshold. If the sensed energy level is lower than the preset energy threshold, the communication device 100 determines that the operating channel is currently unoccupied or "idle." Conversely, if the sensed energy reaches or exceeds the preset energy threshold, it indicates ongoing transmission or significant interference, thus the communication device 100 determines that the operating channel is "busy." Therefore, by performing CCA detection on its operating channel, the communication device 100 can determine whether the operating channel is currently idle or busy.

[0042] In another example embodiment, the predetermined condition may further include the fact that the end time of the predetermined time (i.e., the RX pause time length TH) exceeds a predetermined time threshold with respect to the nearest Target Beacon Transmission Time (TBTT). In this example embodiment, one of the conditions that the communication device 100 evaluates before entering RF sleep mode is to confirm whether it is currently "not in a TBTT". This involves determining the proximity of an upcoming, regularly scheduled AP beacon frame transmission. Specifically, the communication device 100 evaluates whether the remaining time interval until the next known TBTT is long enough. If the next TBTT is imminent, meaning that the AP's beacon frame is expected to be transmitted soon, the communication device 100 will avoid entering RF sleep mode to ensure that it remains fully active (i.e., RX enabled) to receive the necessary regularly scheduled beacon frame transmissions. Instead, the communication device 100 will only consider entering RF sleep mode if it determines that there is a sufficient time interval before the next predetermined TBTT.

[0043] In other embodiments, additional factors such as Received Signal Strength Indication (RSSI) and RX transmission volume may also be considered. For example, the communication device 100 may detect the RSSI and RX transmission volume of the communication device 100 before time point T0 (i.e., during data transmission). If the RSSI is greater than the RSSI threshold (e.g., -60 dBm) and the RX transmission volume is less than the RX transmission volume threshold (e.g., 100 Mbps), the controller 10b triggers the RF transceiver module 10a to enable the function of the RF sleep mode. In other words, when the RSSI is less than the RSSI threshold, the controller 10b can prevent the RF transceiver module 10a from entering the RF sleep mode to prioritize reliable signal reception. This is because, under weak signal conditions, the communication device 100 can avoid potential packet loss and instability in data reception by preventing the wireless chip 10 from entering the RF sleep mode. When the RX transmission volume is greater than the RX transmission volume threshold, the controller 10b can prevent the RF transceiver module 10a from entering the RF sleep mode to maintain data transmission efficiency. This is because when the RX transmission volume exceeds the RX transmission volume threshold, it indicates that the communication device 100 may be experiencing a large data throughput. Therefore, to prevent performance degradation and ensure smooth data flow, the controller 10b can prevent the RF transceiver module 10a from entering RF sleep mode when the RX transmission volume is high. Thus, the RF transceiver module 10a can remain fully active (enabled) to handle incoming data throughput without creating a bottleneck. Furthermore, in some embodiments, the RX pause time length TH is preset or adjustable, and its value affects the speed at which the wireless chip 10 enters RF sleep mode to save power. In one example, the preset duration TA of the RX on state in RF sleep mode is greater than or equal to the preset duration TB of the RX off state in RF sleep mode. More specifically, the RX pause time length TH is greater than the preset duration TB of the RX off state in RF sleep mode, but this disclosure is not limited thereto.

[0044] After the conditions for entering the RF sleep mode are met within the RX pause time length TH, the controller 10b can control the RF transceiver module 10a to enter the RF sleep mode at time point T1. In Figure 3, the RF sleep mode can be executed by periodically alternating between the RX on state and the RX off state within the time length TR. When the RF transceiver module 10a enters the RX on state, the controller 10b can enable all functions of the RF transceiver module 10a to achieve full data reception capability. Therefore, the communication device 100 can perform CCA detection on the operating channel. The time length of the RX on state is represented by TA. Furthermore, in the RX on state, the controller 10b determines whether to exit the RF sleep mode based on the result of the CCA detection. In particular, once the operating channel is detected to be busy, the controller exits the RF sleep mode and returns to the active mode. When the RF transceiver module 10a enters the RX off state, the controller 10b can disable part of the function of the RX circuit of the RF transceiver module 10a to reduce power consumption. Because some functions of the RF transceiver module 10a are disabled (e.g., turned off or in standby mode), the RX off state consumes less power than the RX on state. The duration of the RX off state is denoted by TB. The time interval between time points T1 and T2 can be referred to as the alternation cycle of the RF sleep mode. Furthermore, during the RX on state of the RF sleep mode, the device performs CCA detection on its operating channel. When busy operation is detected in the RX on state of the RF sleep mode, it means that at least one data packet may be transmitted to the communication device 100. Therefore, the controller 10b controls the RF transceiver module 10a to exit the RF sleep mode and re-enter the active mode, for example at time point T3. By doing so, the communication device 100 can reliably receive incoming data packets.

[0045] It should be understood that in conventional communication devices, the duration of the "listening state" or keep-alive time (KAT), i.e., the period during which the device remains fully active to receive possible incoming data packets after data transmission is completed, is typically a predetermined fixed time, such as 200 milliseconds. However, in the communication device 100 provided in this embodiment of the invention, the conventional listening state is replaced by an RF sleep mode. The key difference is that the RF sleep mode is dynamically adaptable. Specifically, during the periodic RX on state within the RF sleep mode, the communication device 100 listens to the operating channel. If the operating channel is detected to be busy (e.g., by CCA detection), the communication device 100 immediately exits the RF sleep mode and switches back to the normal active mode to handle channel activity (e.g., receive possible incoming data packets). Therefore, the overall duration TR of the RF sleep mode is "non-fixed" before receiving data or entering a deeper power-saving mode, but is dynamically adjusted according to the immediate state of the operating channel. By doing so, the communication device 100 achieves significant power savings during the RF sleep mode while maintaining high throughput efficiency by quickly returning to the active mode when communication is needed.

[0046] Figure 4 is a schematic diagram of the communication device 100 receiving data packets in a first scenario. As previously mentioned, the communication device 100 can be considered as a station. The AP 20 may transmit data packets to the communication device 100 at any time. It should be understood that during the operation of the communication device 100 in RF sleep mode, the communication device 100 periodically alternates between an RX on state and an RX off state. Specifically, the communication device 100 performs CCA detection during each RX on state in RF sleep mode. The purpose of performing CCA detection during each RX on state is to prevent the communication device 100 from missing incoming data packets. Due to the power-saving characteristics of RF sleep mode, the RX function of the RF transceiver module 10a can only be intermittently active / enabled. Therefore, it is possible that data packets arriving during the RX off state may not be detected. To minimize the risk of undetected packets, the communication device 100 may perform CCA detection during each RX on state in RF sleep mode to detect the presence of any wireless signals. If the operating channel is occupied (or the operating channel is busy), it means that there may be ongoing or upcoming data transmission. Therefore, communication device 100 exits RF sleep mode and returns to active mode (normal non-intermittent RX on state). This RX state transition mechanism ensures that communication device 100 can be in a fully receiving state to receive the entire incoming data packet. In Figure 4, the operating channel is detected as busy at time T4. Controller 11b triggers (or controls) RF transceiver module 10a to switch from RF sleep mode to active mode at time T4 to receive data packets. In this embodiment, time T4 is the time when AP 20 begins transmitting data packets to communication device 100. Therefore, RF transceiver module 10a of communication device 100 can successfully receive the "entire" data packet in active mode. Furthermore, after RF transceiver module 10a successfully receives the data packet, communication device 100 can transmit an acknowledgment signal (ack) to AP 20.

[0047] Figure 5 is a schematic diagram of the communication device 100 receiving retransmitted data packets in the second scenario. As previously described, CCA detection can be performed during each RX-on state of the RF sleep mode. Therefore, in this embodiment, AP 20 may transmit data packets to the communication device 100 at time T5. However, at time T5, the RF transceiver module 10a of the communication device 100 is in the RX-off state. The RF transceiver module 10a cannot detect data packets at time T5. This causes the communication device 100 to be unable to switch from the RF sleep mode to the active mode to receive data packets "immediately" at time T5. As time progresses, the RF transceiver module 10a will enter the RX-on state at time T6. Once the RF transceiver module 10a enters the RX-on state, the communication device 100 (specifically, the wireless chip 10) performs CCA detection on the operating channel. Therefore, at time T6, the communication device 100 can detect whether the operating channel is busy or idle. When the operating channel is detected as busy, the controller 10b will trigger or control the RF transceiver module 10a to switch from RF sleep mode to active mode to receive data packets.

[0048] It should be understood that although the controller 10b triggers or controls the RF transceiver module 10a to switch from RF sleep mode to active mode to receive data packets at time T6, the data packets received by the RF transceiver module 10a starting from time T6 are incomplete. This is because a portion of the data packet (e.g., the portion transmitted from time T5 to time T6) is not received by the RF transceiver module 10a (or is missed). Therefore, even if the RF transceiver module 10a starts receiving data packets at time T6, packet reception will still fail (due to incompleteness). When the RF transceiver module 10a fails to fully receive the data packet, an acknowledgment signal will not be generated. Since the AP 20 does not receive an acknowledgment signal, the AP 20 may retransmit the data packet to the communication device 100. Since the wireless chip 10 is now in active mode, the data packet retransmitted at time T7 can be fully received by the wireless chip 10. In other words, in communication device 100, even if a data packet cannot be received in a certain RX-off state, the RF transceiver module 10a will inevitably switch from RF sleep mode to active mode in the next alternation cycle. Therefore, the data packet only needs to be retransmitted once to ensure that it is received by the RF transceiver module 10a. Thus, communication device 100 saves power without causing excessive reception delay.

[0049] Figure 6 is a schematic diagram of communication device 100 receiving retransmitted data packets in the third scenario. As described in Figure 5, when a "part" of the data packet is in the RX-on state of the RF sleep mode, RF transceiver module 10a will detect that the channel is busy based on CCA detection. Therefore, RF transceiver module 10a can fully receive the data packet in active mode when the data packet is retransmitted. In Figure 6, the process of data packet transmission from AP 20 to communication device 100 occurs during the duration of the RX-off state. Therefore, communication device 100 cannot detect any part of the data packet. For example, the data packet is transmitted to communication device 100 between time point T8 and time point T9. Since RF transceiver module 10a of communication device 100 is in the RX-off state between time point T8 and time point T9, it cannot perform reception or CCA detection. Subsequently, RF transceiver module 10a enters the RX-on state at time point T10. After entering the RX-on state, RF transceiver module 10a gains the ability to perform CCA detection. When the operating channel is detected as busy, controller 10b triggers or controls RF transceiver module 10a to switch from RF sleep mode to active mode to receive data packets. It should be understood that since RF transceiver module 10a cannot detect data packets between time point T8 and time point T9, an acknowledgment signal will not be generated. Because AP 20 does not receive an acknowledgment signal, AP 20 will retransmit the data packet. If the data packet is transmitted from AP 20 to communication device 100 after the time point when RF transceiver module 10a enters the RX-on state in RF sleep mode (time point T10), wireless chip 10 can receive the complete data packet and enter active mode. Conversely, if the data packet is transmitted from AP 20 to communication device 100 before the time point when RF transceiver module 10a enters the RX-on state (time point T10), communication device 100 will encounter the scenario described in Figure 5. In Figure 6, communication device 100 can fully receive the data packet after the second retransmission. In Figure 6, even if the RF transceiver module 10a fails to receive a data packet due to the RX being off, the RF transceiver module 10a can attempt to receive the complete data packet in the next alternation cycle, thereby saving power and minimizing reception delay.

[0050] In one embodiment, the power-saving mechanism implemented in the communication device 100 relies on precise management of the receiver state time, specifically by controlling the RX pause time length TH, the RX off state time length TB, and the RX on state time length TA, and their related parameters. The RX pause time length TH can be represented in discrete units, with each unit representing 32 microseconds (μs). For example, the RX pause time length TH ranges from 0 to 1023 units, equivalent to a time span of 0 μs to 32736 μs (approximately 32.7 milliseconds). This adjustable range allows the communication device 100 to adapt to different network requirements and power-saving strategies. The RX on state time length TA can be represented in units of 2 microseconds (μs), providing higher resolution to ensure time accuracy. The RX on state time length TA can range from 0 to 63 units, equivalent to a time range of 0 μs to 126 μs. Similar to the RX on state time length TA, the RX off state time length TB can be represented in units of 2 microseconds (μs). The RX off state duration (TB) can range from 0 to 255 units, corresponding to a time range of 0 μs to 510 μs. A longer RX off state duration results in greater power savings. In one embodiment, preset settings for RX pause duration, RX off state duration, and RX on state duration are introduced to provide a balance between power saving and communication performance. For example, the RX pause duration is set to 1024 μs. The RX on state duration is set to 60 μs. The RX off state duration is set to 60 μs. All parameters and settings can be dynamically or statically adjusted to optimize communication performance and power consumption based on specific application requirements and environmental conditions.

[0051] In one embodiment, a power-saving level for the RF sleep mode can be set. This power-saving level is one of a first power-saving level and a second power-saving level, wherein the second power-saving level is more power-efficient and consumes less power than the first power-saving level. For example, when set to the first power-saving level, at least a portion of the RX circuitry in the communication device is in a standby state during the RX-off state of the RF sleep mode. Specifically, under the first power-saving level, during the RX-off state of the RF sleep mode, the physical layer (PHY) circuitry that processes signal transmission and reception (e.g., via a space interface) is placed in a "standby" state. In the standby state, the PHY circuitry consumes significantly less power than in the fully active state, but retains a basic configuration and can quickly return to full operation when the device needs to switch back to the RX-on state. Meanwhile, the frequency synthesizer (SX) used to generate the precise carrier frequency required for wireless communication (e.g., within the RF transceiver module 10a) remains operational (enabled). By keeping the SX active under the first power-saving level, the communication device 100 ensures that the necessary local oscillator signal is always available. This configuration avoids the longer delays required for restarting and stabilizing SX, thus facilitating a rapid switchback from the RX off state to the RX on state. Furthermore, the antenna interface or path is placed in a "standby" state, meaning at least one antenna is in standby mode. Similar to the standby state of the PHY circuitry, the antenna interface in standby mode consumes less power than when performing transmission or reception (enabled state). In standby mode, the antennas are not completely off, and because SX remains on, RF signal paths connected to these antennas can be considered available or quickly become available upon switching back to the RX on state.

[0052] When set to the second power-saving level, at least a portion of the RX circuitry in the communication device is in a powered-off state during the RX-off state of the RF sleep mode. Specifically, in the second power-saving level, during the RX-off state, similar to the first power-saving level, the PHY circuitry is placed in a "standby" state. In this state, the PHY circuitry consumes less power than in the active mode, while retaining certain configurations to allow for rapid startup. However, in the second power-saving level, the SX (e.g., within the RF transceiver module 10a) is completely powered off. Powering off the SX stops the generation of the carrier frequency, thus providing a significant power-saving effect compared to the first power-saving level where the SX remains on. Powering off the SX results in the RF signal path that depends on its generated frequency being disabled. Therefore, restarting and stabilizing the SX when switching back to the RX-on state requires a certain amount of time, resulting in a longer wake-up delay compared to the first power-saving level. Furthermore, the deeper power-saving effect of the second power-saving level also includes placing the antenna interface or path in a "power-off" state. This power-off state represents a deeper power-saving condition for the antenna elements compared to the "standby" state used in the first power-saving level. When the antenna is off, it consumes the least power, but requires a longer initialization or startup time when switching back to active mode (or RX on).

[0053] Therefore, the second power-saving level provides a way to configure the RX off state by prioritizing power reduction through turning off the frequency synthesizer (SX off) and placing the antenna in the off state, wherein the PHY circuitry enters a standby state. The second power-saving level achieves lower power consumption than the first power-saving level during the RX off interval, but requires a longer transition time to return to the fully operational RX on state.

[0054] Figure 7 is a schematic flowchart of the communication device 100 performing a power-saving method. The power-saving method includes steps S701 to S704. Any technical or hardware modifications are within the scope of this embodiment. Steps S701 to S704 are shown below.

[0055] Step S701: Perform data transfer in active mode.

[0056] Step S702: After the data transmission is completed, enter the RF sleep mode to periodically alternate between the RX on state and the RX off state.

[0057] Step S703: During the RX-on state of the RF sleep mode, perform CCA detection on the operation channel of the communication device 100 to determine whether the operation channel is idle or busy.

[0058] Step S704: If the operation channel is detected to be busy during the RX-on state of RF sleep mode, switch from RF sleep mode to active mode.

[0059] Details of steps S701 to S704 have already been described. Therefore, they are omitted here. The communication device 100, which is capable of providing an RF sleep mode during receive listening, has significant advantages over conventional wireless communication devices. Conventional wireless communication devices often consume excessive power during receive listening because the RX circuit remains active (enabled) even when no data packets are exchanged. While reducing the duration of the listening state can save some power, this can introduce potentially significant delays if data arrives shortly after the device enters a deeper sleep state. However, the communication device 100 addresses these disadvantages by employing an RF sleep mode during receive listening. By periodically alternating between an RX-on state and an RX-off state during listening, the communication device 100 achieves significantly reduced power consumption compared to a receiver that remains continuously active. Furthermore, the power-saving method of this embodiment of the invention achieves power saving while mitigating the performance degradation associated with simply shortening the listening time. The periodic RX-on state ensures that the communication device 100 retains the ability to frequently listen to the channel and detect incoming transmissions or channel activity (e.g., by CCA detection). Furthermore, the power-saving method of the present invention can also ensure reliable reception of data packets arriving even during the RX off state when the AP first attempts to retransmit the data packet, typically with minimal additional delay. Therefore, the communication device 100 provides an effective balance between enhanced power-saving efficiency and maintaining communication performance (i.e., low-latency packet reception).

[0060] In summary, embodiments of the present invention disclose a power-saving method for a communication device. The core concept of the power-saving method focuses on mitigating excessive power consumption during the receive listening state. The power-saving method involves implementing an RF sleep mode by periodically alternating between an RX-on state and an RX-off state. This periodic alternation significantly reduces power consumption during listening compared to conventional methods, while maintaining low-latency communication performance through frequent channel listening and efficient packet reception during the RX-on state—an advantage that cannot be achieved simply by shortening the listening time. Therefore, embodiments of the present invention provide an improved balance between power efficiency and operational responsiveness, widely applicable to various communication devices, such as stations or access points in wireless local area networks (e.g., Wi-Fi systems), and particularly suitable for battery-powered devices requiring extended operational life.

[0061] Although the present invention has been described by way of example and according to preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. Rather, it is intended to cover various variations and similar structures (as will be apparent to those skilled in the art), such as combinations or substitutions of different features in different embodiments. Therefore, the scope of the appended claims should be given the broadest interpretation to cover all such variations and similar structures.

[0062] The use of ordinal terms such as “first,” “second,” “third” to modify the elements of a patent application in the scope of the patent application does not in itself indicate any priority, priority, or order of one element of a patent application relative to another element of a patent application, or the temporal order of performing method actions, but is only used as a marker to distinguish one element of a patent application with the same name from another element element with the same name.

[0063] Although the embodiments and advantages of the present invention have been described in detail, it should be understood that various changes, substitutions, and modifications can be made to the present invention without departing from the spirit and scope defined by the claims. For example, new embodiments can be derived by combining several parts of different embodiments. The described embodiments are for illustrative purposes only and are not intended to limit the present invention. The scope of protection of the present invention shall be determined by the appended claims. Those skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention. [Simplified Explanation of the Diagram]

[0028] The accompanying drawings (in which the same numerals denote the same components) illustrate embodiments of the present invention. The drawings are included to provide a further understanding of embodiments of the present disclosure, and are incorporated in and constitute a part of the present disclosure. The drawings illustrate implementations of embodiments of the present disclosure and, together with the description, serve to explain the principles of the embodiments of the present disclosure. It is understood that the drawings are not necessarily drawn to scale, as some components may be shown out of scale to clearly illustrate the concepts of the embodiments of the present disclosure. Figure 1 is a timing diagram of the active mode and power-saving mode of a wireless communication device. Figure 2 is a schematic diagram of a communication device according to an embodiment of the present invention. Figure 3 is a schematic diagram of the chip power variation of the communication device in Figure 1 in active mode and radio frequency (RF) sleep mode. Figure 4 is a schematic diagram of the communication device in Figure 1 receiving data packets in a first scenario. Figure 5 is a schematic diagram of the communication device in Figure 1 receiving retransmitted data packets in a second scenario. Figure 6 is a schematic diagram of the communication device in Figure 1 receiving retransmitted data packets in a third scenario. Figure 7 is a flowchart of the communication device in Figure 1 performing a power-saving method. In the following detailed description, numerous specific details are set forth for illustrative purposes so that those skilled in the art may more thoroughly understand the embodiments of the invention. However, it will be apparent that one or more embodiments may be practiced without these specific details, and different embodiments or different features disclosed in different embodiments may be combined as needed, and should not be limited to the embodiments illustrated in the accompanying drawings.

Claims

1. A power-saving method for a communication device, comprising: Perform data transfer in active mode; Detect the Received Signal Strength Indicator (RSSI) of the communication device; Detect the RX transmission of the communication device; If the RSSI is greater than the RSSI threshold and the RX transmission amount is less than the RX transmission amount threshold, the communication device is triggered to enable the radio frequency (RF) sleep mode. After data transmission is completed, the device enters the RF sleep mode to periodically alternate between the receive (RX) on state and the RX off state. During the RX on state of the RF sleep mode, an idle channel assessment (CCA) detection is performed on the operating channel of the communication device to determine whether the operating channel is idle or busy. If the operating channel is detected to be busy during the RX on state of the RF sleep mode, the device switches from the RF sleep mode to the active mode.

2. The method as described in request item 1, wherein, During the RX off state of the RF sleep mode, at least a portion of the RX circuitry of the communication device is in standby mode and / or disabled.

3. The method as described in request item 1, wherein, During the RX-on state of the RF sleep mode or during the active mode, the RX circuit of the communication device is enabled.

4. The method as described in request item 1, wherein, Entering the RF sleep mode after data transmission is completed includes: determining whether predetermined conditions for entering the RF sleep mode are met after data transmission is completed; and if the predetermined conditions are met, entering the RF sleep mode.

5. The method as described in request item 4, wherein, The method further includes: before entering the RF sleep mode, the communication device sets an RX pause time length to continuously determine the predetermined condition during the RX pause time length.

6. The method as described in claim 4, wherein, The predetermined conditions include: the communication device does not transmit within the predetermined time; the communication device does not receive within the predetermined time; and the operating channel is detected as idle within the predetermined time.

7. The method as described in claim 6, wherein, The pre-defined condition also includes that the end time of the pre-defined time exceeds the pre-defined time threshold between the nearest Target Beacon Transmission Time (TBTT).

8. The method as described in request item 1, wherein, The method further includes: setting a power saving level for the RF sleep mode, wherein the power saving level is set to one of a first power saving level and a second power saving level; wherein when the power saving level is set to the first power saving level, at least a portion of the RX circuits in the communication device are in a standby state in the RX off state of the RF sleep mode, and when the power saving level is set to the second power saving level, at least a portion of the RX circuits in the communication device are in a turned-off state in the RX off state of the RF sleep mode.

9. The method as described in claim 8, wherein, When the power saving level is set to the first power saving level, in the RF sleep mode with the RX off state, the physical layer (PHY) circuit is in standby mode, the frequency synthesizer (SX) is in enabled state, and at least one antenna is in standby mode. When the power saving level is set to the second power saving level, in the RF sleep mode with the RX off state, the PHY circuit is in standby mode, the SX is off state, and at least one antenna is off state.

10. A communication device, comprising: Radio frequency (RF) transceiver module; A controller, coupled to and configured to control the RF transceiver module to perform operations, including: performing data transmission in active mode; detecting the Received Signal Strength Indicator (RSSI) of the communication device; detecting the RX transmission amount of the communication device; if the RSSI is greater than an RSSI threshold and the RX transmission amount is less than an RX transmission amount threshold, the controller triggers the RF transceiver module to enable a radio frequency (RF) sleep mode; after data transmission is completed, entering the RF sleep mode to periodically alternate between a receive (RX) on state and an RX off state; during the RX on state of the RF sleep mode, performing a free channel assessment (CCA) detection on the operating channel of the communication device to determine whether the operating channel is idle or busy; and if the operating channel is detected to be busy during the RX on state of the RF sleep mode, switching from the RF sleep mode to the active mode.

11. The communication apparatus as claimed in claim 10, wherein, During the RX off state of the RF sleep mode, at least a portion of the RX circuitry of the communication device is in standby mode and / or disabled.

12. The communication apparatus as claimed in claim 10, wherein, During the RX-on state of the RF sleep mode or during the active mode, the RX circuit of the communication device is enabled.

13. The communication apparatus as claimed in claim 10, wherein, After data transmission is completed, the controller determines whether the predetermined conditions for entering the RF sleep mode are met. If the predetermined conditions are met, the communication device enters the RF sleep mode.

14. The communication apparatus as claimed in claim 13, wherein, Before entering the RF sleep mode, the RX pause time length is set so that the predetermined condition is continuously determined during the RX pause time length.

15. The communication apparatus as claimed in claim 13, wherein, The predetermined conditions include: the communication device does not transmit within the predetermined time; the communication device does not receive within the predetermined time; and the operating channel is detected as idle within the predetermined time.

16. The communication apparatus as claimed in claim 15, wherein, The pre-defined condition also includes that the end time of the pre-defined time exceeds the pre-defined time threshold between the nearest Target Beacon Transmission Time (TBTT).

17. The communication apparatus as claimed in claim 10, wherein, The power saving level of the RF sleep mode is set to one of a first power saving level and a second power saving level. When the power saving level is set to the first power saving level, at least a portion of the RX circuit of the communication device is in standby mode when the RX is off. When the power saving level is set to the second power saving level, at least a portion of the RX circuit of the communication device is in off mode when the RX is off.

18. The communication apparatus as claimed in claim 17, wherein, When the power saving level is set to the first power saving level, the physical layer (PHY) circuit is in standby mode, the frequency synthesizer (SX) is in enabled mode, and at least one antenna coupled to the RF transceiver module is in standby mode. When the power saving level is set to the second power saving level, the PHY circuit is in standby mode, the SX is in disabled mode, and at least one antenna coupled to the RF transceiver module is in disabled mode.

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