WO2018145348A1 - Procédé et appareil pour déterminer un état de canal occupé ou inactif - Google Patents

Procédé et appareil pour déterminer un état de canal occupé ou inactif Download PDF

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Publication number
WO2018145348A1
WO2018145348A1 PCT/CN2017/076831 CN2017076831W WO2018145348A1 WO 2018145348 A1 WO2018145348 A1 WO 2018145348A1 CN 2017076831 W CN2017076831 W CN 2017076831W WO 2018145348 A1 WO2018145348 A1 WO 2018145348A1
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Prior art keywords
channel
cca
signal received
ppdu
received power
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PCT/CN2017/076831
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English (en)
Chinese (zh)
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WO2018145348A9 (fr
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杜振国
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华为技术有限公司
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Priority to CN201780071595.1A priority Critical patent/CN109983831B/zh
Publication of WO2018145348A1 publication Critical patent/WO2018145348A1/fr
Publication of WO2018145348A9 publication Critical patent/WO2018145348A9/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA

Definitions

  • the present application relates to the field of communications technologies, and in particular, to a method and apparatus for determining a busy state of a channel.
  • WiFi Wireless Fidelity
  • IoT Internet of Things
  • WiFi IoT device is introduced in the WiFi IoT standard based on the 2.4G/5 GHz band, wherein the WiFi IoT device is configured with a low-power wake-up radio based on a conventional WiFi interface (ie, 802.11 main radio, 802.11 main module). /Lower Power Wake-up Radio/Receiver (LP-WUR) interface.
  • WiFi interface ie, 802.11 main radio, 802.11 main module.
  • LP-WUR Low Power Wake-up Radio/Receiver
  • the station (Station, STA) shown in Figure 1a is a WiFi IoT device, including 802.11 main radio and LP-WUR, and the Wireless Access Point (AP) is a legacy device, including 802.11 main radio (also known as The 802.11 main module), specifically, when the STA receives the WUR physical layer convergence procedure protocol data unit (PPDU) sent by the AP through the LP-WUR, the LP-WUR sends a wakeup to the STA's 802.11 main radio.
  • the signal activates the 802.11 main radio to communicate data with the AP via the 802.11 main radio.
  • PPDU physical layer convergence procedure protocol data unit
  • the WUR PPDU includes a wideband portion and a narrowband portion, and the wideband portion usually occupies a bandwidth of 20 MHz for backward compatibility (ie, is actually listened to by a conventional device), and the LP-WUR of the STA can receive a narrowband portion. It typically contains the identity of the target device to wake up.
  • a device needs to send a PPDU (to distinguish it from a WUR PPDU, a PPDU in 802.11a/g/n/ac can be called a legacy PPDU, which occupies the smallest channel bandwidth.
  • the process of transmitting a PPDU in the prior art is briefly introduced by sending a Legacy PPDU as an example, which is a bandwidth of 20 MHz, that is, a bandwidth of a broadband portion of the WUR PPDU.
  • the sending device needs to go through two phases before sending the Legacy PPDU.
  • the transmitting device detects that the channel is continuously in an idle state for a distributed inter-frame Spacing (DIFS/Arbitration Interframe Space (AIFS) time. Specifically, if distributed coordination is adopted The Distributed Coordination Function (DCF) protocol, the transmitting device performs Clear Channel Assessment (CCA) on the channel for transmitting the Legacy PPDU, and performs the second phase when it is determined that the channel is continuously in the idle state and reaches the DIFS time.
  • DCF Distributed Coordination Function
  • CCA Clear Channel Assessment
  • the transmitting device performs CCA on the channel for transmitting the legacy PPDU, and when it is determined that the channel is continuously in an idle state and reaches the AIFS time,
  • the second phase ie, the random backoff process
  • the AIFS is related to the QoS class of the service carried by the legacy PPDU to be transmitted, that is, when the legacy PPDU carrying the QoS class service is transmitted, the value of the AIFS is different.
  • Four standards of service QoS are given in the standard (ie, Voice service and Video service).
  • AIFS value default Best Effort service QoS class and Background traffic) corresponding to, AIFS values corresponding to different traffic QoS classes may also be associated with the AP changes and notifying the device.
  • the second stage, through the random backoff If the sending device detects that the channel is in the idle state for a long time after the DIFS/AIFS time and the random backoff timer has a value of 0, the transmitting device randomly takes an integer value in the range [0, CW] for A random backoff timer is set. Then, the sending device continues to perform CCA on the channel. If the sending device detects that the channel is still idle, the random backoff timer performs backoff timing. When the random backoff timer falls back to 0, the sending device sends Legacy. PPDU.
  • the sending device pauses the random backoff timer, and when the transmitting device detects that the channel is in the idle state again, re-executes the first phase and the first The second stage, but the random back-off timer at this time does not need to re-value, but starts from the previously paused timing value and then starts the back-off timing.
  • the channel is required to be in an idle state.
  • the transmitting device determines the busy state of the channel by performing signal detection and energy detection on the 20 MHz channel.
  • the process of judging the busy state of the channel in the standard is called Clear Channel Assessment (CCA).
  • CCA Clear Channel Assessment
  • the transmitting device performs CCA on the channel including signal detection and energy detection, specifically:
  • Signal detection When the transmitting device detects the 802.11 physical header that is valid in the Legacy PPDU, that is, if the preamble portion of a PPDU is correctly received, when the signal receiving power is greater than or equal to a preset threshold (for example, when the Legacy PPDU is occupied) When the channel bandwidth is 20 MHz, the preset threshold is -82 dBm), it is determined that the channel is in a busy state, otherwise the channel is determined to be in an idle state;
  • the threshold set in the energy detection is greater than the threshold set in the signal detection.
  • the existing Legacy PPDU occupies the same bandwidth throughout the transmission process (for example, the Legacy PPDU occupies a bandwidth of 20 MHz), and the WUR PPDU includes a broadband portion and a narrowband portion, that is, the bandwidth occupied during the entire transmission. There is a change. Generally, the bandwidth occupied by the broadband part is 20 MHz, and the bandwidth occupied by the narrowband part is less than 20 MHz, for example, 5 MHz.
  • the transmitting device sends the WUR PPDU, if the existing technology is used to determine the busy state of the channel, It is easy to cause the narrowband portion of the transmitted WUR PPDU to interfere with the signal being transmitted in the channel, thereby greatly increasing the possibility of WUR PPDU transmission failure.
  • the embodiment of the present invention provides a method and a device for determining a busy state of a channel, which are used to reduce the possibility of failure when transmitting a WUR PPDU by using a mechanism for determining a busy state of a channel in the prior art.
  • a method for determining a busy state of a channel including:
  • the sending device When determining that the first physical layer convergence process protocol data unit PPDU needs to be sent, the sending device performs a first CCA on the first channel, obtains a first CCA result, and performs a second CCA on the second channel to obtain a second CCA result;
  • the first PPDU includes a first portion and a second portion, the first portion is before the second portion, and the first portion is transmitted on the first channel, the second portion is transmitted on the second channel, and the second channel is part of the first channel;
  • the transmitting device determines that the channel for transmitting the first PPDU is in an idle state when the first CCA result indicates that the first channel is in an idle state, and the second CCA result indicates that the second channel is in an idle state.
  • the second portion is transmitted on the second channel, and the second channel is part of the first channel Determining the busy state of the first channel and the second channel respectively, and determining that the channel for transmitting the first PPDU is in an idle state when the first channel and the second channel are simultaneously in an idle state, and the prior art channel Compared with the determination of the busy state, the determination result is more accurate, thereby reducing the interference and collision of signals in the channel, thereby improving the probability of successful transmission of the first PPDU.
  • the first CCA result indicates that the first channel is in a busy state
  • the second CCA result indicates that the second channel is in a busy state
  • the sending device performs a first CCA on the first channel according to the following manner to obtain a first CCA result:
  • the transmitting device determines a signal received on the first channel, and measures a signal received power on the first channel according to a signal received on the first channel; and compares the first CCA threshold with the The signal on the first channel receives power, and the first CCA result is obtained, wherein when the signal received power on the first channel is less than the first CCA threshold, the first CCA result indicates the first The channel is in an idle state, and when the signal received power on the first channel is greater than or equal to the first CCA threshold, the first CCA result indicates that the first channel is in a busy state.
  • the sending device performs a second CCA on the second channel according to the following manner to obtain a second CCA result:
  • the transmitting device does not need to be configured with a dedicated narrowband filter in this way, the implementation of the transmitting device is simplified and the cost is reduced.
  • the transmitting device determines the signal received power on the second channel according to the signal received power on the first channel according to the following manner:
  • the signal received power on each subcarrier included in the subcarrier and the signal received power on the first channel determine the signal received power on the second channel.
  • the signal received power on the second channel satisfies the following expression:
  • P 01 is the signal received power on the first channel
  • P 02 is the signal received power on the second channel
  • N is the number of subcarriers included in the first channel
  • M is the The number of subcarriers included in the second channel
  • P K+i is the signal receiving power of the i th subcarrier on the second channel
  • P i is the signal receiving power of the i th subcarrier on the first channel.
  • the sending device performs a second CCA on the second channel according to the following manner, to obtain a second CCA result, including:
  • the transmitting device determines a signal received on the second channel, and measures a signal received power on the second channel according to a signal received on the second channel; and compares a second CCA threshold and The signal on the second channel receives power to obtain the second CCA result, wherein when the signal received power on the second channel is less than the second CCA threshold, the second CCA result indicates the The second channel is in an idle state, and when the signal received power on the second channel is greater than or equal to the second CCA threshold, the second CCA result indicates that the second channel is in a busy state.
  • the first CCA threshold is greater than the second CCA threshold.
  • the bandwidth of the first channel is 20 MHz.
  • the first PPDU is a WUR PPDU.
  • a method for determining a busy state of a channel when transmitting a first PPDU the first PPDU includes a first portion and a second portion, the first portion being located before the second portion, The first part is transmitted on a first channel, the second part is transmitted on a second channel, and the second channel is part of the first channel, the method comprising: transmitting, by the transmitting device, a wideband CCA on the first channel Obtaining a first CCA result; the transmitting device performs a narrowband CCA on the second channel to obtain a second CCA result; when the first CCA result indicates that the first channel is in an idle state, and the second CCA result When the second channel is in an idle state, the transmitting device determines that the channel for transmitting the first PPDU is in an idle state.
  • the first CCA is also referred to as a wideband CCA
  • the second CCA is also referred to as a narrowband CCA.
  • the first CCA result indicates that the first channel is in a busy state
  • the second CCA result indicates that the second channel is in a busy state
  • the transmitting device performs a wideband CCA on the first channel according to the following manner to obtain a first CCA result:
  • the transmitting device measures a first received power, and estimates the first CCA result based on the first received power, where the first received power is a signal received power of the sending device on the first channel .
  • the transmitting device performs a narrowband CCA on the second channel according to the following manner to obtain a second CCA result:
  • the transmitting device measures a second received power, and estimates the second CCA result based on the second received power, where the second received power is a signal received power of the transmitting device on the second channel .
  • the transmitting device may also perform a narrowband CCA on the second channel based on the following manner to obtain a second CCA result:
  • the transmitting device estimates the second CCA result according to the first received power.
  • the transmitting device estimates the second CCA result according to the first received power based on:
  • the transmitting device performs FFT on the signal received on the first channel, and obtains each of the first channels included Signal reception power on subcarriers;
  • the transmitting device estimates the second CCA result according to signal received power and the first received power on each subcarrier included in the first channel.
  • the transmitting device estimates the second CCA result according to the received power of each subcarrier in the first channel and the first power based on:
  • the transmitting device calculates a third received power, where the third received power is a sum of signal received powers on all subcarriers included in the first channel;
  • the transmitting device calculates a fourth received power, where the fourth received power is a sum of signal received powers of all subcarriers included in the second channel, and all subcarriers included in the second channel are Among the subcarriers of the first channel, the subcarriers corresponding to the second channel;
  • the transmitting device estimates the second CCA result according to a signal received power on the second channel.
  • the bandwidth of the first channel is 20 MHz.
  • the PPDU is a WUR PPDU.
  • a second aspect provides an apparatus for determining a busy state of a channel, including: a processor, a first receiver, a second receiver, and a determining unit, wherein the processor is configured to determine that the device needs to send the first physics When the layer aggregation process protocol data unit PPDU, the first receiver and the second receiver are triggered; the first receiver is configured to perform a first clear channel estimation CCA on the first channel under the trigger of the processor to obtain a first CCA result.
  • the second receiver is configured to perform a second CCA on the second channel under the trigger of the processor to obtain a second CCA result; wherein the first PPDU includes a first part and a second part, where the first part is Before the second part, and the first part is sent on the first channel, the second part is sent on the second channel, the second channel is part of the first channel; a determining module, Determining, when the first CCA result indicates that the first channel is in an idle state, and the second CCA result indicates that the second channel is in an idle state, determining that a channel for sending the first PPDU is empty State.
  • the determining unit is further configured to indicate, in the first CCA result, that the first channel is in a busy state, and/or the second CCA result indicates that the second channel is in a busy state At the time, it is determined that the channel for transmitting the first PPDU is in a busy state.
  • the first receiver includes a wideband filter, a first measurement circuit, and a first CCA estimation subunit: wherein the wideband filter is configured to filter out on the first channel a received signal, the first measurement circuit, configured to measure signal received power on the first channel according to a signal received on a first channel; the first CCA estimation subunit, for comparing a first CCA result obtained by using a CCA threshold and a signal received power on the first channel, wherein the first CCA is when a signal received power on the first channel is less than the first CCA threshold The result indicates that the first channel is in an idle state, and when the signal received power on the first channel is greater than or equal to the first CCA threshold, the first CCA result indicates that the first channel is in a busy state.
  • the second receiver includes a narrowband filter, a second measurement circuit, and a second CCA estimation subunit: the narrowband filter is configured to filter out received on the second channel
  • the second measurement circuit is configured to measure signal received power on the second channel according to the received signal on the second channel;
  • the second CCA estimation subunit is configured to compare the second CCA threshold And receiving power from the signal on the second channel, The second CCA result, wherein when the signal received power on the second channel is less than the second CCA threshold, the second CCA result indicates that the second channel is in an idle state, when the second When the signal received power on the channel is greater than or equal to the second CCA threshold, the second CCA result indicates that the second channel is in a busy state.
  • the first CCA threshold is greater than the second CCA threshold.
  • the bandwidth of the first channel is 20 MHz.
  • the first PPDU is a WUR PPDU.
  • a device for determining a busy state of a channel when transmitting a first PPDU where the first PPDU includes a first part and a second part, where the first part is located before the second part, The first part is transmitted on a first channel, the second part is transmitted on a second channel, and the second channel is part of the first channel, characterized in that the apparatus comprises:
  • a first receiving module configured to perform a wideband CCA on the first channel to obtain a first CCA result
  • a second receiving module configured to perform a narrowband CCA on the second channel to obtain a second CCA result
  • the first CCA is also referred to as a wideband CCA
  • the second CCA is also referred to as a narrowband CCA.
  • the first receiving module is equivalent to the first receiver in the device for determining the busy state of the channel provided by the second aspect
  • the second receiving module is equivalent to the device for determining the busy state of the channel provided by the second aspect
  • the second receiver, the determination module is equivalent to the determination unit in the device for determining the busy state of the channel provided by the second aspect.
  • the determining module is further configured to indicate, in the first CCA result, that the first channel is in a busy state, and/or the second CCA result indicates that the second channel is in a busy state At this time, it is determined that the channel for transmitting the first PPDU is in a busy state.
  • the first receiving module includes a wideband filter sub-module for filtering the first channel signal for filtering out signals received on the first channel;
  • the second receiving module includes for the second channel A narrowband filter sub-module for signal filtering; for filtering out signals received on the second channel.
  • the wideband filter sub-module is equivalent to the wideband filter in the apparatus for determining the busy state of the channel provided by the second aspect
  • the narrowband filter submodule is equivalent to the apparatus for determining the busy state of the channel provided by the second aspect. Narrowband filter.
  • the first receiving module is configured to perform a wideband CCA on the first channel according to the following manner to obtain a first CCA result:
  • the first receiving module is configured to measure signal received power on the first channel, and estimate a first CCA result according to signal received power on the first channel.
  • the second receiving module is configured to perform a narrow CCA on the second channel according to the following manner to obtain a second CCA result:
  • the second receiving module is configured to measure signal received power on the second channel, and estimate a second CCA result according to signal received power on the second channel.
  • the bandwidth of the first channel is 20 MHz.
  • the PPDU is a WUR PPDU.
  • a third aspect provides an apparatus for determining a busy state of a channel, including: a processor, a receiver, a narrowband CCA estimating unit, and a determining unit, wherein the processor is configured to determine, in the determining, that the apparatus needs to send the first physical layer convergence process protocol data
  • the receiver and the narrowband CCA estimating unit are triggered, and the receiver is used to trigger on the processor.
  • the first channel performs a first clear channel estimation CCA, and obtains a first CCA result and a signal received power on the first channel
  • the narrowband CCA estimating unit is configured to receive power according to a signal on the first channel under trigger of the processor.
  • the first PPDU includes a first portion and a second portion, the first portion is before the second portion, and the first portion is at the first portion Channel transmission, the second part is sent on the second channel, the second channel is part of the first channel, and the determining unit is configured to indicate that the first channel is in an idle state in the first CCA result And determining, by the second CCA result, that the second channel is in an idle state, determining that a channel for sending the first PPDU is in an idle state.
  • the signal receiving power on the first channel may be an intermediate result obtained during the first CCA of the first channel.
  • the determining unit is further configured to indicate, in the first CCA result, that the first channel is in a busy state, and/or the second CCA result indicates that the second channel is in a busy state At the time, it is determined that the channel for transmitting the first PPDU is in a busy state.
  • the receiver includes a wideband filter, a measurement circuit, and a wideband CCA estimating unit; wherein the wideband filter is configured to filter out signals received on the first channel; Measuring circuit for measuring signal received power on the first channel according to a signal received on the first channel; the wideband CCA estimating unit for comparing the first CCA threshold with the first channel Received by the signal, the first CCA result is obtained, wherein when the signal received power on the first channel is less than the first CCA threshold, the first CCA result indicates that the first channel is in an idle state When the signal received power on the first channel is greater than or equal to the first CCA threshold, the first CCA result indicates that the first channel is in a busy state.
  • the narrowband CCA estimating unit includes an FFT subunit and a CCA estimating subunit; wherein the FFT subunit is configured to perform fast Fourier on the signal received on the first channel. Transforming the FFT to obtain signal received power on each subcarrier included in the first channel; the CCA estimating subunit, configured to determine, according to signal received power on each subcarrier included in the first channel, a signal receiving power of each subcarrier included in the second channel; a signal receiving power according to each subcarrier included in the second channel, a signal receiving power on each subcarrier included in the first channel, and And receiving, by the signal on the first channel, a signal received power on the second channel; and comparing a second CCA threshold with a signal received power on the second channel, to obtain the second CCA result, where When the signal received power on the second channel is less than the second CCA threshold, the second CCA result indicates that the second channel is in an idle state, when the second channel When the received signal power is greater than or equal to the second threshold value
  • the signal received power on the second channel satisfies the following expression:
  • P 01 is the signal received power on the first channel
  • P 02 is the signal received power on the second channel
  • N is the number of subcarriers included in the first channel
  • M is the The number of subcarriers included in the second channel
  • P K+i is the signal receiving power of the i th subcarrier on the second channel
  • P i is the signal receiving power of the i th subcarrier on the first channel.
  • the first CCA threshold is greater than the second CCA threshold.
  • the bandwidth of the first channel is 20 MHz.
  • the first PPDU is a WUR PPDU.
  • a device for determining a busy state of a channel when transmitting a first PPDU where the first PPDU includes a first part and a second part, where the first part is located before the second part, Said first part is transmitted on a first channel, said second part is transmitted on a second channel, said second channel is part of said first channel
  • said means comprising: a receiving module for said first channel Performing a wideband CCA to obtain a first CCA result; a narrowband CCA estimating module, configured to estimate the second CCA result according to the first received power, where the first received power is the receiving module at the first a signal receiving power on the channel; the determining module is configured to determine, when the first CCA result indicates that the first channel is in an idle state, and the second CCA result indicates that the second channel is in an idle state, determining to send the first PPDU The channel is in an idle state.
  • the receiving module is equivalent to the receiver in the apparatus for determining the busy state of the channel provided by the third aspect
  • the narrowband CCA estimating module is equivalent to the narrowband CCA estimating unit in the apparatus for determining the busy state of the channel provided by the third aspect
  • the determination module is equivalent to the determination unit in the device for determining the busy state of the channel provided by the second aspect.
  • the first CCA result indicates that the first channel is in a busy state
  • the second CCA result indicates that the second channel is in a busy state
  • the receiving module includes a wideband filter sub-module for first channel signal filtering for obtaining a signal received on the first channel; the narrowband CCA estimation module does not include any filter sub-module, But the FFT sub-module is configured to perform FFT on the signal received on the first channel to obtain signal receiving power on each sub-carrier included in the first channel.
  • the broadband filter sub-module is equivalent to the wideband filter in the apparatus for determining the busy state of the channel provided by the third aspect
  • the FFT sub-module is equivalent to the FFT in the apparatus for determining the busy state of the channel provided by the third aspect. Subunit.
  • the receiving module is configured to perform a wideband CCA on the first channel according to the following manner to obtain a first CCA result:
  • the receiving module is configured to measure the first received power, and estimate the first CCA result based on the first received power, where the first received power is a signal received power on the first channel.
  • the narrowband CCA estimation module estimates the second CCA result based on the first received power based on:
  • the second received power is a sum of signal received powers on all subcarriers included in the first channel
  • the third received power is a sum of signal received powers of all subcarriers included in the second channel, and all subcarriers in the second channel are all children of the first channel a subcarrier corresponding to the second channel in the carrier;
  • the second CCA result is estimated based on signal received power on the second channel.
  • the bandwidth of the first channel is 20 MHz.
  • the first PPDU is a WUR PPDU.
  • FIG. 1 is a schematic diagram of an application scenario for transmitting a WUR PPDU
  • FIG. 1b is a schematic diagram of an application scenario of an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of a WUR PPDU frame according to an embodiment of the present application.
  • 3 is a schematic flowchart of sending a legacy PPDU
  • FIG. 4 is a schematic diagram of a scenario in which a device 1 and a device 2 simultaneously transmit a legacy PPDU and a WUR PPDU;
  • FIG. 5 is a schematic diagram of a power spectral density rule for transmitting a WUR PPDU
  • FIG. 6 is a schematic diagram of a scenario when a WUR is transmitted using the power spectral density rule shown in FIG. 5;
  • FIG. 7 is a schematic flowchart of a method for determining a busy and idle state of a channel according to an embodiment of the present application
  • FIG. 8 is a schematic diagram of a frame structure of a WUR PPDU according to an embodiment of the present application.
  • FIG. 9 is a schematic structural diagram of subcarriers included on a 20 MHz channel according to an embodiment of the present application.
  • FIG. 10 is a schematic diagram of sending a legacy PPDU based on a mechanism to determine a busy and idle state of a channel and transmitting a WUR PPDU based on a mechanism for determining a busy state of a channel according to an embodiment of the present application;
  • FIG. 11 is a schematic structural diagram of an apparatus for determining a busy and idle state of a channel according to an embodiment of the present application.
  • FIG. 11b is a schematic structural diagram of a first receiving module according to an embodiment of the present application.
  • 11c is a schematic structural diagram of a second receiving module according to an embodiment of the present application.
  • 11d is a schematic structural diagram of an apparatus for determining a busy state of a channel according to an embodiment of the present application.
  • FIG. 12 is a schematic structural diagram of an apparatus for determining a busy and idle state of a channel according to an embodiment of the present application
  • FIG. 12b is a schematic structural diagram of a first receiving module according to an embodiment of the present application.
  • 12c is a schematic structural diagram of a narrowband CCA estimation module according to an embodiment of the present application.
  • FIG. 12 is a schematic structural diagram of an apparatus for determining a busy state of a channel according to an embodiment of the present application.
  • the AP can send the first PPDU, and the MAC layer frame carried by the first PPDU can be a unicast frame, such as a wake-up frame sent to STA1; the MAC layer frame carried by the first PPDU can also be Is a broadcast or multicast frame, such as sync frames and Beacon frames.
  • the device that sends the first PPDU may be an AP or a terminal device.
  • the target receiving device of the first PPDU sent by the sending device may be a device that has been associated with the sending device, such as STA1 in FIG. 1b; a target receiving device of the WUR PPDU sent by the sending device, or an unassociated device, such as an AP.
  • the Beacon frame in the WUR PPDU format is sent to discover the unrelated device that wants to enable the WUR function.
  • the first PPDU may be a WUR PPDU
  • the sending device may be an AP or an STA.
  • the receiving device may be an AP equipped with an LP-WUR, where the STA is a terminal device such as a mobile phone, a sensor, etc.; when the sending device is a STA, the receiving device may be a STA equipped with an LP-WUR, such as a smart watch. , smart bracelet, etc.; or, when the sending device is a STA (such as a mobile phone), the receiving device can also be an AP equipped with an LP-WUR.
  • the transmitting device has the transmitting capability of the first PPDU, and the receiving device configures the interface that receives the first PPDU, that is, the LP-WUR interface.
  • the sending device is an AP
  • the first PPDU is a WUR PPDU.
  • the AP does not represent a specific product form of the sending device.
  • the sending device is an STA
  • the determining channel is busy.
  • the method of the state is similar to the method of determining the busy state of the channel when the sending device is an AP.
  • the method for determining the busy state of the channel is similar to the method for determining the busy state of the channel when the first PPDU is a WUR PPDU, and details are not described herein again.
  • the IEEE 802.11 standards organization plans to develop a WiFi IoT standard based on the 2.4G/5 GHz band, which is characterized by low power consumption and long distance.
  • a WiFi IoT device is introduced in the WiFi IoT standard based on the 2.4G/5 GHz band, wherein the WiFi IoT device is configured with a low-power wake-up radio based on a conventional WiFi interface (ie, 802.11 main radio, 802.11 main module).
  • LP-WUR, WUR for short /Lower Power Wake-up Radio/Receiver
  • WUR is collectively referred to as wake-up radio frequency.
  • 802.11 has established the WUR standard study group (Study Group) to study the standardization of WUR. Its standardized task group (Task Group) may be named 802.11ba, in other words. In other words, 802.11ba may be the official
  • the 802.11 main radio in the STA is usually in the off mode, and the 802.11 main radio is activated only when receiving the wake-up signal from the LP-WUR, and then performs data communication with the AP.
  • the STA's LP-WUR is continuously in the receiving state, or intermittently in the receiving state.
  • the LP-WUR receives the Wake-up Packet (also called the wake-up frame) from the AP in the receiving state
  • the 802.11 main is sent to the 802.11 main.
  • the radio sends a wake-up signal to wake up the 802.11 main radio that is off.
  • the AP actually includes 802.11 main radio and LP-WUR logically.
  • the 802.11 main radio is usually an OFDM broadband transmitter, and the WUR PPDU carrying the wake-up frame includes a narrowband portion.
  • the OFDM wideband transmitter can be utilized to generate narrowband portions of the WUR PPDU.
  • a partial subcarrier of the OFDM signal is vacant and only transmits a signal on a narrow band corresponding to the wakeup frame, thereby generating a narrowband signal, which is an example of generating a WUR narrowband signal by using an OFDM wideband transmitter. Therefore, the AP may only include the 802.11 main radio. .
  • the 802.11 main radio and the LP-WUR may also be included.
  • both the AP and the STA shown in Figure 1a have only one antenna.
  • the 802.11 main radio and the LP-WUR use the same frequency band carrier (such as 2.4 GHz), the same antenna can be shared to save cost and simplify. Equipment structure.
  • 802.11 main radio and LP-WUR use carriers of different frequency bands
  • 802.11 main radio and LP-WUR should be configured with different antennas.
  • the 802.11 main radio uses the 5 GHz band
  • the LP-WUR uses the 2.4 GHz band. At this time, the two correspond to different antennas.
  • WUR PPDUs are typically modulated in a manner that is easily demodulated by the receiving device, such as On-Off Key (OOK) modulation. Taking OOK modulation as an example, the receiving device judges the information carried by the received signal by the presence or absence of energy, for example, the energy is 1, and the energy is zero.
  • OOK modulation As an example, the receiving device judges the information carried by the received signal by the presence or absence of energy, for example, the energy is 1, and the energy is zero.
  • the Legacy PPDU is modulated and encoded by using OFDM, BCC/LDPC, etc. on the transmitting device. Accordingly, the receiving device needs to perform Fast Fourier Transformation (FFT) and Forward Error Correction (Forward Error Correction, FEC) complex signal processing operations such as decoding, which require a lot of energy.
  • FFT Fast Fourier Transformation
  • FEC Forward Error Correction
  • the 802.11 main radio of the STA in FIG. 1a may be other communication interfaces, such as Long Time Evolution (LTE).
  • LTE Long Time Evolution
  • the modules for data communication are collectively referred to as a main communication module or a main communication interface (main radio), such as an LTE, WiFi module; a module for wake-up of a device, collectively referred to as a wake-up radio module or a wake-up radio interface (WUR) ).
  • main radio such as an LTE, WiFi module
  • WUR wake-up radio interface
  • the document [11-16-0341-00-lrlp-low-power-wake-up-receiver-follow-up] proposes a specific design of a WUR PPDU (Wake-up packet).
  • the WUR PPDU shown in Figure 2 includes a Legacy PPDU.
  • L-Preamble a Legacy Preamble (L-Preamble) part and a WUR payload part
  • the L-Preamble part includes L-STF, L-LTF, L-SIG, and adopts OFDM mode at a bandwidth of 20 MHz (or an integer multiple of 20 MHz)
  • Send for backward compatibility making traditional WiFi
  • the device can determine that the current data packet is a WiFi data packet, thereby determining the busy state of the channel according to the received signal power of the WiFi data packet and the preset CCA decision threshold. If backward compatibility is not considered, L-STF, L-LTF L-SIG may not exist.
  • the WUR payload (Payload) is partly due to the easy-to-demodulation modulation (such as OOK modulation (such as ASK)) and can be transmitted over a narrower bandwidth, such as 2MHz channel, 4MHz channel, 5MHz channel, etc. (Legacy PPDU occupation The minimum bandwidth of the channel is 20 MHz), thus making the receiving device's receiving energy consumption smaller.
  • the WUR Payload includes a Wake-up Preamble and a MAC part.
  • the Wake-up Preamble functions similarly to the Legacy Preamble for synchronization, AGC, channel estimation, control information indication, etc., and the MAC part is similar to the MAC part of the Legacy PPDU, including MAC header, frame body, frame check sequence (FCS), MAC part may use simple code coding such as repetition code, spreading code, Manchester code to improve reliability, but it is also possible Channel coding is not used. Since the WUR PPDU function is relatively simple, the frame body part may not exist.
  • the Wake-up Preamble includes a sequence of specific sequences. The LP-WUR of the STA does not receive the Legacy Preamble part, but directly detects the specific sequence to identify the beginning of the WUR PPDU.
  • the STA's LP-WUR When the STA's LP-WUR receives the WUR PPDU and detects its own identity (such as unicast/multicast/broadcast address) from the MAC portion of the WUR PPDU, it sends a wake-up signal to the 802.11 main radio.
  • the Wake-up Preamble may also include a Wakeup-Signal (WU-SIG) field for carrying the length of the MAC part and the modulation and coding mode used.
  • WU-SIG Wakeup-Signal
  • the WUR Payload section can also use other modulation methods that are easy to demodulate, such as FSK.
  • the frame structure of the WUR PPDU is only an example of a WURP PDU that carries a wake-up frame. Other structures may be used as long as they can be received by the LP-WUR interface.
  • the PPDUs that can be received by the LP-WUR interface in this application are collectively referred to.
  • the WUR PPDU can be used not only to carry wake-up frames, but also to carry other frames that can be received by the LP-WUR interface, such as synchronization frames for WUR synchronization.
  • the WUR PPDU should include a wideband portion (L-Preamble as shown in Figure 2) and a narrowband portion (such as the WUR Payload portion shown in Figure 2).
  • the wideband part is used for backward compatibility and can be received and parsed by other legacy devices.
  • the broadband part of the WUR PPDU may also include other parts; the narrowband part is used for carrying WUR information and can be used by other devices' LP- WUR interface receives and parses.
  • the broadband part is for channel sensing of third-party legacy devices. In general, the LP-WUR interface does not need to receive and parse the part.
  • a device needs to send a PPDU (to distinguish it from a WUR PPDU, a PPDU in 802.11a/g/n/ac can be called a legacy PPDU, which occupies the smallest channel bandwidth.
  • a mechanism for transmitting a PPDU in the prior art is briefly described by using a legacy PPDU as an example.
  • the sending device Before sending a legacy PPDU, the sending device needs to go through two phases. In the first phase, the sending device detects that the channel is continuously idle for up to DIFS/AIFS. As shown in Figure 3, if the DCF protocol is used, the sending device pair is used. The channel for transmitting the Legacy PPDU is used for CCA.
  • the second phase (ie, the random backoff procedure) is performed, where the DIFS is a predefined predefined duration of the standard, and if the EDCA protocol is used, the transmitting device is used.
  • the AIFS is related to the service QoS level of the legacy PPDU to be transmitted, that is, When the Legacy PPDUs of different service QoS levels are transmitted, the AIFS values are different.
  • the standard provides the default values of the four service QoS levels (that is, the QoS levels of the Voice service, the Video service, the Best Effort service, and the Background service).
  • AIFS value the AIFS value corresponding to the QoS level of different services can also be changed by the AP and notified to the associated device.
  • the second phase, the random backoff process that is, when the transmitting device continues to DIFS/AIFS to detect that the channel is in an idle state and the random backoff timer takes a value of 0, the transmitting device randomly takes a range of [0, CW]. After an integer value is used to set the random backoff timer, the sending device continues to perform CCA on the channel.
  • the random backoff timer When the device detects that the channel is still idle, the random backoff timer performs the backoff timing according to the random integer value. When the random backoff timer falls back to 0, the transmitting device still detects that the channel is idle and sends a Legacy PPDU.
  • the DW is a predefined value, and the value increases as the number of retransmissions of the PPDU to be transmitted increases. If the sending device detects that the channel is busy before the random backoff timer falls back to 0, the random backoff timer is paused, and when the transmitting device detects that the channel is in the idle state again, re-executing in the persistent DIFS/AIFS The busy state of the channel is detected and the random backoff is detected. However, the random backoff timer at this time does not need to re-value, but the time value of the previous pause is followed by the backoff timing.
  • the process of judging the busy state of the channel in the standard is CCA.
  • the transmitting device performs CCA on the channel including signal detection and energy detection, and specifically:
  • Signal detection When the transmitting device detects the 802.11 physical header that is valid in the Legacy PPDU, that is, if the preamble portion of a PPDU is correctly received, when the signal receiving power is greater than or equal to a preset threshold (for example, when the Legacy PPDU is occupied) When the channel bandwidth is 20 MHz, the preset threshold is -82 dBm), it is determined that the channel is in a busy state, otherwise the channel is determined to be in an idle state;
  • the threshold set in the energy detection is greater than the threshold set in the signal detection; regardless of the energy detection or the signal detection, the preset thresholds corresponding to different bandwidths may be different.
  • the channel width of the existing Legacy PPDU is consistent during transmission. For example, each part of the Legacy PPDU occupies a channel of 20 MHz. Therefore, it is reasonable to determine the busy state of the channel based on the CCA detection result of the 20 MHz channel.
  • the WUR PPDU is composed of a wideband portion and a narrowband portion, and the wideband portion is located before the narrowband portion, the wideband portion is transmitted on the first channel, the narrowband portion is transmitted on the second channel, and the second channel is part of the first channel, if still used
  • the existing mechanism will increase the probability of WUR PPDU transmission failure.
  • 13 center frequency points can be planned in the 2.4 GHz band, corresponding to 13 20 MHz WiFi channels.
  • the number n of the center frequency point is also the channel number, such as 20 MHz with the frequency point n as the center frequency.
  • the channel is called channel n.
  • the interval between adjacent frequency points is 5 MHz, which may cause partial overlap of 20 MHz corresponding to different center frequency points.
  • Channel planning in the 2.4 GHz band may vary from country to country. For example, the United States only supports channels 1 to 11, while Japan supports channels 1 to 14, where channel 14 is 12 MHz higher than the center frequency of channel 13.
  • the transmitting device 1 is transmitting a Legacy PPDU on the channel 9, wherein the channel bandwidth occupied by the legacy PPDU is 20 MHz, and the transmitting device 2 is to transmit the WUR PPDU on the channel 6, and the WUR Payload portion is located at the frequency point. 4MHz channel between 7 and frequency 8.
  • the transmitting device 2 When the signal of the transmitting device 1 arrives at the transmitting device 2, the received power strength of the portion between the frequency point 7 and the frequency point 8 is -66 dBm, then, according to the current CCA mechanism, the transmitting device 2 detects that the power on the channel 6 is -66 dBm, less than the energy detection threshold -62 dBm (energy detection threshold -62 dBm corresponds to a channel detection threshold with a bandwidth of 20 MHz), so the transmitting device 2 considers that the channel 6 is in an idle state, thus contending for the channel and transmitting the WUR PPDU.
  • energy detection threshold -62 dBm corresponds to a channel detection threshold with a bandwidth of 20 MHz
  • the legacy PPDU transmitted on the narrowband channel corresponding to the WUR Payload may interfere with the WUR Payload, and for the WUR Payload part, This is a very strong interfering signal that causes the transmission of WUR Payload to be almost unsuccessful.
  • the distance between the transmitting device 1 and the transmitting device 2 is less than 30 m, and the distance between the two covers a serious overlap.
  • the interference with each other is severe, and the transmission of the transmitting device 1 interferes with the transmission device 2 to transmit the WUR PPDU at the receiving end with a great probability.
  • the WUR PPDU adopts OOK, its transmission reliability is relatively poor. Therefore, the probability that the WUR PPDU is successfully transmitted by the signal of the transmitting device 1 is smaller.
  • the transmitting device 2 cannot detect the transmission of the transmitting device 1 according to the conventional CCA mode, so that the WUR PPDU is still transmitted, and the WUR PPDU fails to transmit with a great probability, which wastes channel resources.
  • FIG. 4 only shows an example in which the transmitting device 1 transmits a Legacy PPDU.
  • the above problem obviously also occurs when the transmitting device 1 transmits a WUR PPDU and the WUR Payload portion is located between the frequencies 7 and 8.
  • the first device wakes up the 802.11 main radio by receiving the wake-up frame carried by the WUR PPDU sent by the second device, and then interacts with the second device by the 802.11 main radio.
  • the Power Spectrum Density (PSD) of the WUR Payload portion of the WUR PPDU cannot be lower than the power spectral density of the transmitted Legacy PPDU.
  • the PUR of the WUR Payload of the WUR PPDU cannot be lower than the PSD of its L-Preamble. Since the channel bandwidth occupied by the transmission WUR Payload is narrower, the power is smaller than the L-Preamble power in the same PSD case. Therefore, in general, the PSD of the WUR Payload must be higher than the PSD of the L-Preamble to ensure the coverage of the former. Not less than the latter, as shown in Figure 5.
  • AP1 and AP2 use the same narrowband channel to transmit WUR Payload. Since the power spectral density of the WUR Payload is higher than the L-preamble part, AP1 may hear the L-preamble of AP2 and find out according to the energy detection. The received power is less than -62dBm. At this time, AP1 considers that the channel is in an idle state, thereby transmitting a WUR PPDU. However, in fact, AP2 is transmitting a WUR PPDU, which causes a collision between the WUR Payload portion of the WUR PPDU sent by AP1 and AP2, which reduces the probability of successful PPDU transmission.
  • the main problem of using the traditional CCA mechanism as the CUA of the WUR PPDU is that the CCA result of the wideband channel (20 MHz) cannot accurately characterize the channel state of the narrowband channel. Interference may be concentrated on certain narrowband channels, while the wideband channel CCA averages these interferences over the broadband such that the channel is erroneously considered to be idle, resulting in an increased likelihood of WUR PPDU transmission failure.
  • the first PPDU when the first PPDU includes the first portion and the second portion, and the first portion is before the second portion, and the first portion is transmitted on the first channel, the second portion is transmitted on the second channel, and the second channel is the second channel
  • the determination result is more accurate, thereby reducing interference and collision of signals in the channel, thereby improving the probability of success of the first PPDU transmission.
  • the method for determining a busy state of a channel in the embodiment of the present application includes:
  • Step 700 After determining that the first physical layer convergence procedure protocol data unit PPDU needs to be sent, the sending device performs a first clear channel estimation CCA on the first channel, obtains a first CCA result, and performs a second CCA on the second channel, to obtain a second CCA result; wherein the first PPDU includes a first portion and a second portion, the first portion is before the second portion, and the first portion is transmitted on the first channel, the second portion is transmitted on the second channel, and the second channel is first One of the channels section;
  • Step 701 The transmitting device determines that the channel used for sending the first PPDU is in an idle state when the first CCA result indicates that the first channel is in an idle state, and the second CCA result indicates that the second channel is in an idle state.
  • the channel occupied by the first channel is 20 MHz
  • the channel occupied by the second channel is located on a channel with a bandwidth of 5 MHz in the 20 MHz channel, and the second channel is part of the first channel, that is, the second channel is the first channel.
  • a subchannel of a channel is 20 MHz
  • the channel occupied by the second channel is located on a channel with a bandwidth of 5 MHz in the 20 MHz channel
  • the second channel is part of the first channel, that is, the second channel is the first channel.
  • the first PPDU may be a WUR PPDU, and may also be a PPDU that conforms to the first PPDU frame structure of the embodiment of the present application, which is not limited herein.
  • the transmitting device determines that the channel for transmitting the first PPDU is in a busy state.
  • the first CCA may be referred to as a wideband CCA
  • the second CCA may be referred to as a narrowband CCA.
  • the broadband CCA and the narrowband CCA are simultaneously performed in the embodiment of the present application, the prior art Compared with the method of performing only the wideband CCA, the determination of the channel busy state is more accurate.
  • the method for simultaneously performing the broadband CCA and the narrowband CCA to determine the busy state of the channel in the embodiment of the present application may also be referred to as dual CCA (Dual-CCA).
  • the first part is a Legacy part of the WUR PPDU, wherein the Legacy part includes an L-Preamble part, and may also include other parts, and the second part is a WUR Payload part.
  • the first channel may be a 20 MHz channel and the second channel is a subchannel of the 20 MHz channel.
  • the sending device may perform the first CCA on the first channel according to the following manner to obtain the first CCA result:
  • the transmitting device determines a signal received on the first channel, and measures a signal received power on the first channel according to the signal received on the first channel; comparing the first CCA threshold with the signal received power on the first channel, Obtaining a first CCA result, wherein when the signal received power on the first channel is less than the first CCA threshold, the first CCA result indicates that the first channel is in an idle state, and the signal received power on the first channel is greater than or equal to the first At the CCA threshold, the first CCA result indicates that the first channel is busy.
  • the first CCA may be a channel CCA of 20 MHz in the current 802.11a/g/n/ac, including energy detection and signal detection
  • the first CCA threshold may include a threshold 1 and a threshold 2, wherein the threshold 1 is used for energy detection.
  • the threshold 2 is used for signal detection, wherein energy detection and signal detection can be performed simultaneously.
  • the values of threshold 1 and threshold 2 may be different.
  • the CCA threshold may be -62 dBm
  • the CCA threshold may be -82 dBm.
  • the sending device detects the physical header of the signal on the first channel, comparing the threshold 2 with the signal receiving power on the first channel, when the transmitting device does not detect the physical header of the signal on the first channel, comparing The threshold 1 and the signal on the first channel receive power.
  • the sending device performs the second CCA on the second channel to obtain the second CCA result, which may include two modes:
  • the first way is to directly measure the received power of the signal on the second channel:
  • the transmitting device determines a signal received on the second channel, and measures a signal received power of the signal received on the second channel according to the signal received on the second channel; and compares the second CCA threshold with the second channel Receiving power of the signal, obtaining a second CCA result, wherein when the signal received power on the second channel is less than the second CCA threshold, the second CCA result indicates that the second channel is in an idle state, and the signal received power on the second channel When greater than or equal to the second CCA threshold, the second CCA result indicates that the second channel is in a busy state.
  • the first mode can be implemented on the premise that the transmitting device is configured with a narrowband filter corresponding to the second channel, and the narrowband signal on the second channel can be filtered through the narrowband filter, thereby measuring the signal receiving power on the second channel. .
  • the second CCA is a CCA on the second channel transmitting the WUR Payload, and at least includes energy detection, and may also include energy detection and signal detection.
  • the thresholds of the first CCA and the second CCA may be different.
  • the transmitting device performs signal detection of the second CCA on the premise that the transmitting device detects a valid WUR PPDU physical header (ie, a Wake-up Preamble portion).
  • the second CCA threshold may include a threshold 3 for performing energy detection and a threshold 4 for performing signal detection, wherein the energy detection and the signal detection may be performed simultaneously .
  • the values of threshold 3 and threshold 4 may be different, specifically:
  • the transmitting device determines the second channel. In a busy state; otherwise, the transmitting device determines that the second channel is in an idle state.
  • threshold 3 is greater than threshold 4.
  • the signal receiving power of the second channel is greater than or equal to the threshold 3, it is determined that the second channel is in a busy state, and when the signal receiving power of the second channel is less than the threshold 3, it is determined as The second channel is in an idle state; or, if the signal received power of the second channel is greater than the threshold 3, it is determined that the second channel is in a busy state, and when the signal received power of the second channel is less than or equal to the threshold 3, the second is determined as The channel is in an idle state.
  • the signal detection is similar to the above, and will not be repeated here.
  • the signal detection and energy detection of the second CCA can also be performed simultaneously, as long as the result of any one of the detection modes is that the channel is busy, the second CCA result indication The second channel is in a busy state; the second CCA result indicates that the second channel is in an idle state only when the CCA result of the signal detection and the energy detection indicates that the second channel is in an idle state.
  • the first CCA threshold includes a threshold 1 and a threshold 2
  • the second CCA threshold includes a threshold 3 and a threshold 4, wherein the threshold 1 and the threshold 3 are used for energy detection, Threshold 2 and threshold 4 are used for signal detection, and the first CCA threshold is greater than the second CCA threshold.
  • the threshold 1 is greater than the threshold 3 and the threshold 2 is greater than the threshold 4.
  • the first CCA threshold is greater than the second CCA threshold, which means that the threshold for energy detection (ie, threshold 1) in the first CCA threshold is greater than the second CCA threshold.
  • the second way is to indirectly estimate the received power of the signal on the second channel:
  • the transmitting device can generate a narrowband signal with an OFDM wideband transmitter.
  • the sending device (such as an AP) does not need to consider power saving, so the LP-WUR interface may not be configured.
  • the transmitting device itself does not need to configure a narrowband filter from the perspective of transmitting the WUR PPDU alone. If the narrowband filter is deliberately configured in order to perform the Dual-CCA proposed in the present application, it will obviously lead to an increase in additional cost and complexity.
  • the received power of the wideband channel can be used to estimate the received power of the narrowband channel.
  • the transmitting device determines the signal receiving power on the second channel according to the signal received power on the first channel; and compares the second CCA threshold with the signal receiving power on the second channel to obtain a second CCA result, wherein, when the second When the signal received power on the channel is less than the second CCA threshold, the second CCA result indicates that the second channel is in an idle state, and when the signal received power on the second channel is greater than or equal to the second CCA threshold, the second CCA result indicates the second Channel In a busy state.
  • the transmitting device may determine the signal receiving power on the second channel according to the signal receiving power on the first channel according to the following method:
  • the transmitting device performs fast Fourier transform FFT on the signal received on the first channel to obtain signal receiving power on each subcarrier included in the first channel; and then receives according to signals on each subcarrier included in the first channel.
  • Power determining signal receiving power of each subcarrier included in the second channel; and receiving power according to signals of each subcarrier included in the second channel, signal receiving power on each subcarrier included in the first channel, and
  • the signal on one channel receives power and determines the received power of the signal on the second channel.
  • a wideband eg, 20 MHz channel
  • the transmitting device can estimate the received power of the signal on the second channel according to the following formula:
  • P 01 is the signal receiving power on the first channel
  • P 02 is the signal receiving power on the second channel
  • N is the number of subcarriers included in the first channel
  • M is the subcarrier included in the second channel.
  • the number of P K+i is the signal receiving power of the i-th subcarrier on the second channel
  • P i is the signal receiving power of the i th subcarrier on the first channel.
  • the advantage of this solution is that the transmitting device does not need to be configured with a special narrow-band filter, which simplifies the implementation of the transmitting device and reduces the cost; the disadvantage is that the solution can only achieve energy detection, but can not achieve signal detection, because the signal detection requirements
  • the transmitting device first needs to detect the start of the narrowband portion of the first PPDU. For example, when the first PPDU is a WURPPDU, the correct Wake-up preamble is detected, and this detection requires that the signal must be narrowband filtered first.
  • the transmitting device can also determine the signal received power on the second channel based on the signal received power on the first channel based on:
  • the transmitting device performs fast Fourier transform FFT on the signal received on the first channel to obtain signal receiving power on each subcarrier included in the first channel; and receives power according to signals on each subcarrier included in the first channel. And determining signal receiving power on each subcarrier included in the second channel, and summing signal receiving power on each subcarrier included in the second channel to obtain signal receiving power on the second channel.
  • the first method is used to directly measure the signal received power on the second channel
  • the second method is used to indirectly estimate the signal received power on the second channel
  • the narrowband filtering of the signal on the second channel needs to be configured in the transmitting device. , In some cases it may be an overhead.
  • the energy detection (ED) threshold and the signal detection (SD) threshold of the 20 MHz channel CCA are -62 dBm and -82 dBm, respectively.
  • the CCA threshold of the device 2 on the 4 MHz narrowband channel is:
  • the device 2 cannot detect the physical header (ie, the L-preamble portion) of the Legacy PPDU sent by the device 1, only energy detection can be used.
  • the wideband CCA since the signal reception power on the 5 MHz channel between the frequency point 7 and the frequency point 8 is -66 dBm ⁇ -62 dBm, the first CCA result indicates that the 5 MHz channel between the frequency point 7 and the frequency point 8 is in an idle state;
  • the narrowband CCA since the signal reception power on the 4 MHz channel between the frequency point 7 and the frequency point 8 is -66.97 dBm>-69 dBm, the second CCA result indicates that the 4 MHz channel between the frequency point 7 and the frequency point 8 is busy. status.
  • the device 2 determines that the channel currently used to send the first PPDU is in a busy state, so the DIFS/AIFS idle time waiting and the random backoff process are not immediately executed, that is, the first PPDU is not sent, and It is to continue to listen to the channel. This avoids the device 2 transmitting the first PPDU with a high probability of failure, reducing the waste of channel resources.
  • the device 2 detects that the channel for transmitting the first PPDU is in an idle state according to the Dual-CCA rule, it starts to perform the DIFS/AIFS idle time waiting and the random backoff process, and when the random backoff timer is reduced to 0, the device 2 sends the first A PPDU.
  • the channel busy state must be determined by the Dual-CCA mechanism.
  • the wideband CCA and the narrowband CCA can be performed synchronously. After determining the busy state of the channel according to the first CCA result and the second CCA result, the transmitting device performs the DIFS/AIFS idle time waiting and the random backoff procedure is the same as sending the legacy PPDU.
  • the main difference of the present application is that the rules for determining whether the channel is idle are different, that is, whether the channel is idle according to the results of the wideband CCA and the narrowband CCA.
  • the traditional CCA mechanism is used to determine the busy state of the channel, and when the first PPDU is to be sent, the Dual-CCA mechanism is used to determine that the channel is busy, as shown in FIG.
  • the DCF access mechanism the sending device waits for the DIFS time when performing DIFS/AIFS idle time waiting; if the EDCA access mechanism is used, the sending device waits for AIFS time when performing DIFS/AIFS idle time waiting, at this time, AIFS
  • the value is determined by the QoS level of the data to be transmitted buffered on the transmitting device, for example, using the same QoS level as the data with the highest QoS level in the data to be transmitted.
  • the sending device sends the WUR PPDU, it is possible to use only the DCF access mechanism.
  • the sending device when it needs to send a legacy PPDU, it can determine the busy state of the channel according to the existing CCA mechanism.
  • a device for determining a busy state of a channel is provided in the embodiment of the present application.
  • the method for determining a channel busy state device is a method for determining a busy state of a channel in the embodiment of the present application.
  • the device for determining the busy state of the channel reference may be made to the implementation of the method, and the repeated description will not be repeated.
  • the apparatus for determining the busy state of the channel includes: the processor 1100, the first receiver 1110, the second receiver 1120, and the determination. Unit 1130, wherein
  • the processor 1100 is configured to trigger the first receiver 1110 and the second receiver 1120 when determining that the apparatus needs to send the first physical layer convergence process protocol data unit PPDU.
  • a first receiver 1110 configured to perform a first clear channel estimation CCA on the first channel, triggered by the processor 1100, to obtain a first CCA result;
  • a second receiver 1120 configured to perform a second CCA on the second channel under the trigger of the processor 1100, to obtain a second CCA result
  • the first PPDU includes a first part and a second part, the first part is before the second part, and the first part is sent on the first channel, the second part is sent on the second channel, and the second part is part of the first channel;
  • the determining unit 1130 is configured to determine that the channel for transmitting the first PPDU is in an idle state when the first CCA result indicates that the first channel is in an idle state, and the second CCA result indicates that the second channel is in an idle state.
  • the determining unit 1130 is further configured to determine to send the first when the first CCA result indicates that the first channel is in a busy state, and/or the second CCA result indicates that the second channel is in a busy state.
  • the channel of the PPDU is busy.
  • the first receiver 1110 includes a wideband filter 1111, a first measurement circuit 1112, and a first CCA estimation subunit 1113 as shown in FIG. 11b:
  • the second receiver 1120 includes a narrowband filter 1121, a second measurement circuit 1122, and a second CCA estimation subunit 1123 as shown in FIG. 11c:
  • the narrowband filter 1120 is configured to filter out the signal received on the second channel; the second measurement circuit 1121 is configured to measure the received power of the signal on the second channel according to the signal received on the second channel; the second CCA The estimating subunit 1123 is configured to compare the second CCA threshold with the signal received power on the second channel to obtain a second CCA result, wherein the second CCA result indication is when the signal received power on the second channel is less than the second CCA threshold The second channel is in an idle state, and when the signal received power on the second channel is greater than or equal to the second CCA threshold, the second CCA result indicates that the second channel is in a busy state.
  • the first CCA threshold is greater than the second CCA threshold.
  • the bandwidth of the first channel is 20 MHz.
  • the first PPDU is a WUR PPDU.
  • the processor 1110, the determining unit 1130, and the first CCA estimating subunit 1113 and the second CCA estimating subunit 1123 may be integrated on one processing chip (such as a CPU), or may be separately integrated in different embodiments.
  • the implementation of the processing chip (such as a CPU) or the like, or implemented by a specific circuit, is not limited herein.
  • a device for determining a busy state of a channel is shown in Figure 11d.
  • the apparatus 10 is configured to determine a channel busy state when the first PPDU is sent, where the first PPDU includes a first part and a second part, the first part Before the second part, the first part is sent on the first channel, the second part is sent on the second channel, the second channel is part of the first channel, and the device is specifically composed of three parts: the first receiving module 11 is used for Performing a wideband CCA on the first channel to obtain a first CCA result; the second receiving module 12 is configured to perform a narrowband CCA on the second channel to obtain a second CCA result; and the determining module 13 is configured to be the first The CCA result indicates that the first channel is in an idle state and the second CCA result indicates that the second channel is in an idle state, and determines that the channel for transmitting the first PPDU is in an idle state.
  • the first receiving module 11 includes at least a wideband filter, a measuring circuit, and a wideband CCA estimating portion for respectively receiving a wideband signal, measuring a received power of the wideband signal, and obtaining a first CCA result based on the received power of the wideband signal.
  • the second receiving module 12 includes at least a narrowband filter, a measuring circuit, and a narrowband CCA estimating portion for receiving the narrowband signal, measuring the received power of the narrowband signal, and obtaining the second CCA result based on the received power of the narrowband signal, respectively.
  • the determining module 13 is configured to determine a channel busy state based on the first CCA result and the second CCA result, which may be implemented in a processor or by a special circuit.
  • the first receiving module 11 and the second receiving module 12 correspond to two independent receivers, which are respectively used for receiving and processing the wideband signal and the narrowband signal.
  • the first receiving module 11 may be a conventional WiFi receiver
  • the second receiving module 12 may be a WUR receiver.
  • the apparatus for determining the busy state of the channel includes a processor 1210, a receiver 1220, a narrowband CCA estimating unit 1230, and a determining unit 1240. among them,
  • the processor 1210 is configured to trigger the receiver 1220 and the narrowband CCA estimating unit 1230 when determining that the apparatus needs to send the first physical layer convergence procedure protocol data unit PPDU.
  • the receiver 1220 is configured to perform a first clear channel estimation CCA on the first channel, triggered by the processor 1210, to obtain a first CCA result and a signal received power on the first channel;
  • the narrowband CCA estimating unit 1230 is configured to perform a second CCA on the second channel under the trigger of the processor 1210 to obtain a second CCA result.
  • the first PPDU includes a first part and a second part, the first part is before the second part, and the first part is sent on the first channel, the second part is sent on the second channel, and the second part is part of the first channel;
  • the determining unit 1240 is configured to determine that the channel for transmitting the first PPDU is in an idle state when the first CCA result indicates that the first channel is in an idle state, and the second CCA result indicates that the second channel is in an idle state.
  • the determining unit 1240 is further configured to determine to send the first when the first CCA result indicates that the first channel is in a busy state, and/or the second CCA result indicates that the second channel is in a busy state.
  • the channel of the PPDU is busy.
  • the receiver 1220 as shown in FIG. 12b includes a wideband filter 1221, a measurement circuit 1222, and a wideband CCA estimating unit 1223;
  • the wideband filter 1221 is configured to filter out signals received on the first channel;
  • the measuring circuit 1222 is configured to measure signal received power on the first channel according to signals received on the first channel;
  • wideband CCA estimation The unit 1223 is configured to compare the first CCA threshold with the signal received power on the first channel to obtain a first CCA result, where the first CCA result indicates the first when the signal received power on the first channel is less than the first CCA threshold The channel is in an idle state. When the signal received power on the first channel is greater than or equal to the first CCA threshold, the first CCA result indicates that the first channel is in a busy state.
  • the narrowband CCA estimating unit 1230 includes an FFT subunit 1231 and a CCA estimating subunit 1232;
  • the FFT sub-unit 1231 is configured to perform fast Fourier transform FFT on the signal received on the first channel.
  • a signal receiving power to each subcarrier included in the first channel a signal receiving power to each subcarrier included in the first channel
  • the CCA estimating subunit 1232 is configured to determine, according to signal receiving power on each subcarrier included in the first channel, each subcarrier included in the second channel Signal receiving power; determining, according to signal receiving power of each subcarrier included in the second channel, signal receiving power on each subcarrier included in the first channel, and signal receiving power on the first channel, determining the second channel Receiving power; and comparing the second CCA threshold with the signal received power on the second channel to obtain a second CCA result, wherein when the signal received power on the second channel is less than the second CCA threshold, the second CCA result indicates The second channel is in an idle state, and when the signal received power on the second channel is greater than or equal to the second CCA threshold, the second CCA result indicates that the second channel is in a busy state
  • the signal received power on the second channel satisfies the following expression:
  • P 01 is the signal receiving power on the first channel
  • P 02 is the signal receiving power on the second channel
  • N is the number of subcarriers included in the first channel
  • M is the subcarrier included in the second channel.
  • the number of P K+i is the signal receiving power of the i-th subcarrier on the second channel
  • P i is the signal receiving power of the i th subcarrier on the first channel.
  • the first CCA threshold is greater than the second CCA threshold.
  • the bandwidth of the first channel is 20 MHz.
  • the first PPDU is a WUR PPDU.
  • the processor 1210, the determining unit 1230, the narrowband CCA estimating unit 1230, and the wideband CCA estimating unit 1223 may be integrated on one processing chip (such as a CPU), or may be separately integrated into different processing chips ( It is implemented on a CPU or the like, or is implemented by a specific circuit, and is not limited herein.
  • the FFT sub-unit 1231 and the CCA estimation sub-unit 1232 included in the narrow-band CCA estimation unit 1230 may be implemented by different circuits, or may be implemented by different processing chips, or implemented by the same processing chip, which is not limited herein.
  • an apparatus for determining a busy state of a channel when transmitting a first PPDU is configured as shown in FIG. 12d.
  • the apparatus 20 is configured to determine a channel busy state when the first PPDU is sent, where the first PPDU includes a first part and a second part, the first part is located before the second part, the first part is sent on the first channel, and the second part is in the second part.
  • the second channel is part of the first channel
  • the device 20 is specifically composed of three parts: a receiving module 21, configured to perform a wideband CCA on the first channel to obtain a first CCA result; and a narrowband CCA estimation module 22 And for estimating the second CCA result based on the first received power, where the first received power is a received power of the receiving module on a received signal on the first channel; and a determining module 23 is configured to: When the first CCA result and the second CCA result are both idle, it is determined that the channel state is idle.
  • the receiving module 21 includes at least a wideband filter, a measuring circuit, and a wideband CCA estimating portion for receiving the wideband signal, measuring the received power of the wideband signal, and obtaining the first CCA result based on the received power of the wideband signal, respectively.
  • the narrowband CCA estimation module 22 includes at least an FFT sub-module and a CCA estimating portion for performing FFT on the wideband received signal obtained by the receiving module 21 to obtain the received power of the received signal of the wideband signal on each subcarrier, the latter being based on each The received power of the received signal on the subcarriers and the total received power measured by the receiving module 21 on the first channel estimate the second CCA result.
  • the determining module 23 is configured to determine a channel busy state based on the first CCA result and the second CCA result, and may be implemented in a processor (such as a CPU), or may be implemented by a special circuit.
  • the receiving module 21 can be a conventional WiFi receiver, and the narrowband CCA estimating module can be implemented by a processor (such as a CPU) or a dedicated circuit.
  • embodiments of the present application can be provided as a method, system, or computer program product. Therefore, the embodiments of the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Moreover, embodiments of the present application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • Embodiments of the present application are described with reference to flowchart illustrations and/or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present application. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG.
  • These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device.
  • the computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device.
  • the apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.
  • These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device.
  • the instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé et un appareil permettant de déterminer un état de canal occupé ou inactif, servant à réduire la possibilité de défaillance de transmission PPDU WUR dans des mécanismes de l'état de la technique pour déterminer un état de canal occupé ou inactif. Le procédé comprend les étapes suivantes : lors de la détermination du fait qu'une première unité de données de protocole de procédure de convergence de couche physique (PPDU) doit être envoyée, un dispositif d'envoi effectue une première CCA sur un premier canal pour obtenir un premier résultat de CCA et effectue une seconde CCA sur un second canal pour obtenir un second résultat de CCA ; et, lorsque le premier résultat de CCA indique que le premier canal est dans un état inactif et que le second résultat de CCA indique que le second canal est dans un état inactif, le dispositif d'envoi détermine que le canal destiné à envoyer la première PPDU est dans un état inactif. L'état d'occupation ou d'inactivité du canal utilisé pour envoyer la première PPDU est déterminé au moyen de la détermination de l'état d'occupation ou d'inactivité des deux canaux, et par conséquent, par rapport à l'état de la technique, les résultats de détermination sont plus précis, augmentant la probabilité de réussite lors de la transmission de la première PPDU.
PCT/CN2017/076831 2017-02-07 2017-03-15 Procédé et appareil pour déterminer un état de canal occupé ou inactif WO2018145348A1 (fr)

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Citations (3)

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US8531980B2 (en) * 2010-06-29 2013-09-10 Intel Corporation Multi-channel communication station for communicating a multi-channel PPDU and methods of reducing collisions on secondary channels in multi-channel wireless networks
WO2014112707A1 (fr) * 2013-01-16 2014-07-24 엘지전자 주식회사 Procédé pour réaliser une réduction de puissance dans un système de réseau local sans fil et appareil correspondant
WO2015198144A2 (fr) * 2014-06-27 2015-12-30 Techflux, Ltd. Procédé et dispositif de transmission d'une unité de données

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CN105191476A (zh) * 2013-05-02 2015-12-23 Lg电子株式会社 在无线lan系统中动态感测信道的方法及其设备
CN105247943A (zh) * 2013-06-03 2016-01-13 高通股份有限公司 用于畅通信道评估的方法和装置
US20160037537A1 (en) * 2014-08-01 2016-02-04 Spreadtrum Communications (Shanghai) Co., Ltd. Method and apparatus for controlling clear channel assessment threshold

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