CN116193498A - Channel busy and idle state evaluation method and device and electronic equipment - Google Patents

Abstract

The application discloses a channel busy and idle state evaluation method, a device and electronic equipment. Channel busy state assessment includes: receiving an air interface signal by adopting a first gain in a first time interval to obtain a first digital signal; performing first idle channel assessment based on the first digital signal to obtain a first idle channel assessment result; receiving an air interface signal by adopting a second gain in a second time interval to obtain a second digital signal in response to the first idle channel estimation result that the channel is busy, wherein the second gain is smaller than the first gain; judging whether saturation distortion exists in the first digital signal or not; and responding to the saturation distortion of the first digital signal, performing second idle channel assessment based on the second digital signal, and taking a second idle channel assessment result as a channel busy state judgment result. When other channels have signals with larger energy, compared with the prior art, the method can reduce the false alarm probability of channel busy state evaluation.

Description

Channel busy and idle state evaluation method and device and electronic equipment

Technical Field

The present invention relates to the field of wireless communications technologies, and in particular, to a method, an apparatus, and an electronic device for evaluating a channel busy/idle state.

Background

"listen before talk" (Listen Before Talk, LBT) is a widely used mechanism in contention-based wireless communications, where a communication device listens to the wireless environment of a current channel before transmitting data to evaluate the busy state of the current signal, and if the channel is busy, waits for the channel to be idle before transmitting to avoid channel usage collision.

Carrier sense multiple access/collision avoidance (Carrier Sense Multiple Access/Collision Avoidance, CSMA/CA) is a listen before talk mechanism employed by wireless local area networks. The communication device needs to perform clear channel assessment (Clear Channel Assessment, CCA) before transmitting data, if the channel is clear, the communication device can perform channel competition, and transmit data after competing for the channel, if the channel is busy, the communication device needs to wait for the channel to turn to be clear before continuing the transmission flow. For example, in the CCA mechanism of the 802.11 protocol, the current channel is considered busy if the signal energy present in the channel is greater than the CCA detection threshold, or if the presence of a particular signal conforming to the present protocol is detected in the channel.

When a wireless local area network operates in an unlicensed frequency band, a few channels are often occupied by multiple devices simultaneously within a limited available spectrum. When the communication device performs idle channel assessment on the current channel, the communication device needs to receive an idle signal, and signals of other channels are inevitably included in the idle signal. When the signal energy of other channels is larger, the radio frequency analog circuit of the receiver is easy to generate saturation distortion, and the generated nonlinear products can leak to the current channel. If the energy of the leakage signal is larger than the CCA detection threshold, the CCA result is busy for the current channel even when the current channel of the air interface is idle, and then the transmission is delayed, so that the throughput rate of the network is reduced.

The following takes the air interface signal of the 802.11b protocol as an example to illustrate the effect on the current channel when there is a strong signal on other channels. In the scenario shown in fig. 1, the current channel is idle, but there is a strong signal from an adjacent channel that is 40MHz apart from the current channel. Fig. 1 shows a schematic diagram of a signal spectrum obtained after frequency conversion of an air interface signal by using a zero intermediate frequency receiver, and from the diagram, it can be seen that a strong signal appears in the current channel bandwidth due to leakage of a nonlinear product generated by saturation distortion of a radio frequency analog circuit to the current channel. For the signals obtained after frequency conversion, the influence of signals of adjacent channels can be eliminated by a low-pass filtering mode, but nonlinear products of the radio frequency analog circuit leaked to the current channel cannot be processed, so that the adverse influence on the idle channel evaluation result is generated.

Disclosure of Invention

It is an object of the present application to provide a method for reducing the probability of evaluating false alarms for current channel busy states when more energetic signals are present on other channels.

In one aspect of the present application, a channel busy state evaluation method is provided, which includes: receiving an air interface signal by adopting a first gain in a first time interval to obtain a first digital signal; performing first idle channel assessment based on the first digital signal to obtain a first idle channel assessment result; receiving an air interface signal by adopting a second gain in a second time interval to obtain a second digital signal in response to the first idle channel estimation result that the channel is busy, wherein the second gain is smaller than the first gain; judging whether saturation distortion exists in the first digital signal or not; and responding to the first digital signal with saturation distortion, performing second idle channel assessment based on the second digital signal, and taking the second idle channel assessment result as a channel busy/idle state judgment result.

In some embodiments, determining whether saturation distortion exists for the first digital signal comprises: judging whether the absolute value of the difference between a signal strength change value and a gain adjustment value exceeds a preset threshold, wherein the signal strength change value is the difference between the signal strength of the first digital signal and the signal strength of the second digital signal, and the gain adjustment value is the difference between the first gain and the second gain; and confirming that saturation distortion exists in the first digital signal in response to the absolute value of the difference between the signal strength variation value and the gain adjustment value exceeding a preset threshold.

In some embodiments, the method further comprises: confirming that no saturation distortion exists in the first digital signal in response to the absolute value of the difference between the signal strength variation value and the gain adjustment value not exceeding a preset threshold; and taking the first idle channel evaluation result as a channel busy state judgment result.

In some embodiments, performing a second idle channel assessment based on the second digital signal, and using the second idle channel assessment result as a channel busy state decision result includes: if the first idle channel assessment result is triggered based on an energy detection mode, comparing the second signal strength with a second energy detection threshold; and in response to the second signal strength being greater than the second energy detection threshold, determining that the channel state is busy, otherwise determining that the channel state is idle.

In some embodiments, the first clear channel assessment uses a first energy detection threshold for energy detection, the second energy detection threshold is greater than or equal to a difference between the first energy detection threshold and the gain adjustment value, the gain adjustment value being a difference between the first gain and the second gain.

In some embodiments, performing a second idle channel assessment based on the second digital signal, and using the second idle channel assessment result as a channel busy state decision result includes: if the first idle channel assessment result is triggered based on a carrier sense mode, detecting whether the second digital signal contains a second sequence or not by adopting the carrier sense mode; and in response to detecting the second sequence, judging that the channel state is busy, otherwise, judging that the channel state is idle.

In some embodiments, the first clear channel assessment uses a first sequence for carrier sensing, the first sequence having a length that is greater than or equal to a length of the second sequence.

In some embodiments, before receiving the air interface signal with the second gain, the method further comprises: determining a gain reduction value based on a signal strength of the first digital signal; subtracting the gain reduction value from the first gain to obtain the second gain.

In some embodiments, the length of the first time interval is greater than the length of the second time interval.

In another aspect of the present application, there is provided a channel busy state evaluation apparatus, including: the receiving unit is configured to receive the air interface signal by adopting a first gain in a first time interval, output a first digital signal, and receive the air interface signal by adopting a second gain in a second time interval when the channel is busy as a result of the first idle channel assessment, so as to obtain a second digital signal, wherein the second gain is smaller than the first gain; a first clear channel assessment unit configured to perform a first clear channel assessment based on the first digital signal, and output the first clear channel assessment result; a gain adjustment unit configured to set the receiving unit to receive a null signal at the second gain during the second time interval in response to the first clear channel assessment result being that the channel is busy; a saturation distortion judging unit configured to judge whether saturation distortion exists in the first digital signal; and a second clear channel assessment unit configured to perform a second clear channel assessment based on the second digital signal in response to the first digital signal having saturation distortion, and to use the second clear channel assessment result as a channel busy/clear status determination result.

In another aspect of the present application, there is provided an electronic device, including: a receiver, a memory and a processor, wherein the receiver is configured to receive an air interface signal and obtain a digital signal under the control of the processor; the memory stores instructions executable by the processor, the instructions causing the processor to perform the steps of: controlling the receiver to receive an air interface signal by adopting a first gain in a first time interval to obtain a first digital signal; performing first idle channel assessment based on the first digital signal to obtain a first idle channel assessment result; responding to the first idle channel estimation result to be that the channel is busy, and controlling the receiver to receive an air interface signal in a second time interval by adopting a second gain to obtain a second digital signal; judging whether saturation distortion exists in the first digital signal or not; and responding to the first digital signal with saturation distortion, performing second idle channel assessment based on the second digital signal, and taking the second idle channel assessment result as a channel busy/idle state judgment result.

The foregoing is a summary of the application and there may be cases where details are simplified, summarized and omitted, so those skilled in the art will recognize that this section is merely illustrative and is not intended to limit the scope of the application in any way. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Drawings

The above-mentioned and other features of the present application will be more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. It is appreciated that these drawings depict only several embodiments of the present application and are therefore not to be considered limiting of its scope. The present application will be described more specifically and in detail by using the accompanying drawings.

Fig. 1 shows a signal spectrum schematic diagram obtained after a receiver performs frequency conversion on an air interface signal in a scene that a current channel is idle but a strong signal exists in an adjacent channel with a 40MHz interval with the current channel;

fig. 2 shows a block diagram of a common zero intermediate frequency receiver;

fig. 3 shows a schematic diagram of a channel busy state assessment method 100 according to an embodiment of the present disclosure;

fig. 4 shows a time allocation schematic of the main steps involved in the channel busy state assessment method 100 of the present disclosure;

fig. 5 illustrates one embodiment of step 150 of the channel busy state evaluation method 100 of the present disclosure;

fig. 6 shows an exemplary block diagram of a channel busy state evaluation apparatus 200 according to an embodiment of the present disclosure;

fig. 7 shows an exemplary block diagram of the saturation distortion judging unit 240 of the channel busy state estimating apparatus 200.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like reference numerals generally refer to like elements unless the context indicates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter of the present application. It will be readily understood that the aspects of the present application, as generally described herein, and illustrated in the figures, may be configured, substituted, and combined in a wide variety of different configurations, all of which are explicitly contemplated as part of this application.

There are mainly two ways of Clear Channel Assessment (CCA), namely, an energy detection way and a carrier sense way. The energy detection mode judges whether the intensity of the received signal exceeds an energy detection threshold or not, if yes, the channel state is judged to be busy, and if not, the channel state is judged to be idle. The carrier sense mode judges whether the received signal contains specific signal characteristics or not, if yes, the channel state is judged to be busy, otherwise, the channel state is judged to be idle. The specific signal characteristic in the carrier sense mode may be a specific carrier, or a specific signal sequence, or other characteristics, and the present disclosure does not limit the specific mode of carrier sense, depending on different system requirements and specific implementation of the receiver. The wireless communication device may perform CCA using one of the two methods, or may perform CCA using both methods. When two CCA modes are used simultaneously, it is generally determined that the channel state is busy as long as either mode determines that the channel state is busy.

Whether in the energy detection mode or the carrier sensing mode, the idle signal can be received in a certain time interval, then CCA is performed based on the received signal in the time interval, and the length of the time interval for idle channel assessment also depends on the system requirement and the specific implementation of the communication device. Typically, the communication device needs to complete the clear channel assessment within a CCA time window specified by the protocol.

Fig. 2 shows a block diagram of a zero intermediate frequency receiver commonly used in a communication device, where Antenna is an Antenna, LNA (Low Noise Amplifier) is a low noise amplifier, and is used to amplify an air interface signal, and the amplification factor of the LNA may be adjusted by setting the gain of the LNA; LO (Local Oscillator) is a local oscillator for generating a local oscillation signal, mixing the local oscillation signal and a 90 ° phase-shifted signal thereof with an LNA output signal to obtain two signals, i.e. an In-phase signal and a Quadrature signal

Representing a mixer; LPF (Low Pass Filter) is a low-pass filter for low-pass filtering the signal output by the mixer to filter out signals outside the current channel bandwidth; PGA (Programmable Gain Amplifier) is a programmable gain amplifier for amplifying the low-pass filtered signal to match with the processing of the following module, and the gain of the programmable gain amplifier can be set; an ADC (Analog-to-Digital Converter) is an Analog-to-digital converter, which converts Analog signals into digital signals; the digital signals obtained by processing the in-phase component and the quadrature component by the ADC are denoted by I, Q in the figure, respectively.

The channel busy state evaluation method of the present disclosure is described below with reference to the accompanying drawings.

Fig. 3 shows a schematic diagram of a channel busy state assessment method 100 of an embodiment of the present disclosure, the method 100 being usable in various communication devices employing a CCA mechanism. Fig. 4 shows a time allocation schematic of the main steps involved in the channel busy state evaluation method 100 of the present disclosure. As shown in fig. 3, the method 100 includes the following steps.

In step 110, the communication device receives an air interface signal with a first gain in a first time interval, and obtains a first digital signal.

Since the strength of the air interface signal is uncertain, the receiver of the communication device will typically set the gain of the radio frequency analog circuit to a higher value during CCA in order to reduce the effects of radio frequency analog circuit noise. Taking the zero intermediate frequency receiver shown in fig. 2 as an example, the gain of the radio frequency analog circuit is the gain of the LNA. For convenience of description, the gain of the receiver referred to in this disclosure refers to the gain of the radio frequency analog circuit of the receiver, unless specifically stated otherwise.

According to the present disclosure, when a communication device starts a CCA, its radio frequency analog circuit uses a first gain G ₁ An air interface signal is received. First gain G ₁ The specific values of (a) may be set with reference to the methods used in the foregoing prior art communication apparatuses, or may be set as needed, and the disclosure is not particularly limited. Referring to FIG. 4, at t ₀ To t ₁ The communication device maintains a first gain G within a first CCA time window of ₁ Is unchanged. After the air interface signal is processed, a first digital signal is obtained, and the homoterm and orthogonal components of the first digital signal obtained in the first CCA time window are respectively used as I ₁ 、Q ₁ Representing the number of sampling points for each component as N ₁ 。

In step 120, the communication device performs a first clear channel assessment based on the first digital signal, to obtain a first clear channel assessment result.

After obtaining the first digital signal, the communication device performs a first CCA based on the first digital signal. The first CCA may adopt an energy detection method or a carrier sense method, or may adopt both methods. When both modes are adopted, if the channel state is judged to be busy in any mode, the channel state is judged to be busy, so that the probability of missed detection when the channel is busy can be reduced.

If the first idle channel evaluation result is that the channel is idle, the current channel is idle, and the condition that the receiver is saturated due to signals in other channels does not exist, so that the channel state can be directly judged to be idle at the moment, and corresponding operation when the channel state is idle is executed according to the protocol specification.

However, in the case that the first clear channel estimation result is that the channel is busy, according to the description about the background art in the present disclosure, in some cases, even if the current channel is actually clear, when other channels exist with signals with larger energy, the radio frequency analog circuit of the receiver of the communication device is easy to generate saturation distortion, and the nonlinear signal generated by the saturation distortion leaks to the current channel and cannot be filtered by the low-pass filter, which may also result in that the first CCA result is that the channel is busy. It is clear that in this case the first CCA result is a false alarm. If the first CCA result is directly taken as a channel state result, the channel usage rate is reduced. Thus, in accordance with the present disclosure, step 130 is further performed in the event that the first clear channel assessment result is that the channel is busy.

In step 130, the communication device receives the air interface signal with a second gain in a second time interval in response to the first idle channel estimation result being that the channel is busy, and obtains a second digital signal.

In this step, if the first CCA is busy, the gain of the RF analog circuit is adjusted to a second gain G ₂ And determines whether to further perform the second CCA according to circumstances. As shown in fig. 4, time t ₁ To t ₂ For the gain adjustment interval, at time t ₂ Gain adjustment of the RF analog circuit to a second gain G ₂ And G ₂ <G ₁ . From time t ₂ To t ₃ The communication device continues to operate at a second gain G during a second CCA time window of ₂ And receiving the air interface signal, and processing the air interface signal to obtain a second digital signal. Similarly, the homonymous and quadrature components of the second digital signal are respectively represented by I ₂ 、Q ₂ Representing the number of sampling points for each component as N ₂ . It should be noted that the length of the gain adjustment interval is typically very short, and the effect of the sampled data of the interval on the evaluation result is substantially negligible, so that, in some embodiments, the starting time of the time window of the second CCA may also be from time t ₁ Starting, or starting from any time in the gain adjustment interval. In some embodiments, the length of the first CCA time window may be greater than the length of the second CCA time window, for reasons related to protocol requirements or for the first CCA to be able to more fully evaluate samples and time, etc. In other embodiments, a first CCA time windowMay also be equal to or less than the length of the second CCA time window.

In some embodiments, a second gain G ₂ Can be set as a first gain G ₁ Subtracting a fixed value.

In other embodiments, the signal power to the ADC should be set to a suitable range, given the limited dynamic range of the ADC. The gain reduction value may be determined based on the signal strength of the first digital signal, and then the first gain G ₁ Subtracting the gain reduction value to obtain a second gain G ₂ . The determination of the gain reduction value may be accomplished in a variety of ways. For example, the corresponding gain reduction value may be calculated by a preconfigured function according to the signal strength of the first digital signal; the corresponding gain reduction value can also be obtained by inquiring a pre-configured table according to the signal intensity of the first digital signal.

In step 140, the communication device determines whether saturation distortion exists in the first digital signal.

When the gain of the receiver of the communication equipment is high, if the power of the air interface signal is high, saturation distortion is easily caused to the radio frequency analog circuit of the receiver, and therefore saturation distortion is caused to the digital signal output by the receiver. If saturation distortion is caused by the current channel presence signal, this will not typically have a significant impact on the CCA, since a CCA based on energy detection may typically determine that the channel state is busy at this time. However, if there is a stronger signal in other channels and the current channel is actually idle, saturation distortion of the rf analog circuit in this case may also cause the CCA to be determined as busy, resulting in a false alarm. Although saturation distortion of the digital signal may be caused by saturation of the radio frequency analog circuit and also by the ADC input signal going beyond the ADC range, the latter may be mitigated by setting the gain of the PGA to an appropriate value. Therefore, by judging whether or not the first digital signal has saturation distortion, it is possible to reflect to some extent whether or not the first CCA result is reliable.

Judging whether the first digital signal has saturation distortion or not can be achieved by adopting different methods according to requirements, and the method is not limited to a specific implementation mode.

For example, in some embodiments, a predetermined saturation threshold may be set, and whether saturation distortion exists in the first digital signal may be determined by determining whether the amplitude of the first digital signal exceeds the saturation threshold, or whether the proportion of the number of sampling points exceeding the saturation threshold to the total number of sampling points exceeds a preset proportion, or the like.

In other embodiments, whether saturation distortion exists in the amplitude of the first digital signal may be determined by determining whether an absolute value of a difference between the signal strength variation value and the gain adjustment value exceeds a preset threshold. The signal strength change value is the difference between the signal strength of the first digital signal and the signal strength of the second digital signal, and the gain adjustment value is the difference between the first gain and the second gain. The signal strength reflects the power level of the signal and can be estimated using the sampled value of the signal.

For convenience of description, the signal strength and gain in the present disclosure are expressed in decibels (dB), and the signal strengths of the first digital signal and the second digital signal are respectively expressed as RSSI ₁ And RSSI ₂ The gain adjustment value is denoted as Δg, and the signal strength variation value is denoted as Δrssi. Δg=g ₁ –G ₂ ，ΔRSSI＝RSSI ₁ –RSSI ₂ . Wherein, the first signal strength RSSI ₁ And a second signal strength RSSI ₂ The calculation can be performed by the following formulas:

wherein I is _i [n]And Q _i [n]The nth sampling points representing the in-phase component and quadrature component, respectively, of the ith digital signal.

For an ideal receiver, if the power of the input signal is kept unchanged and the gain of the receiver is adjusted, the intensity of the received signal also changes synchronously with the gain, and the variation of the gain of the receiver corresponds to the variation of the intensity of the received signal one by one. If the received signal strength and gain are both expressed in db, the first digital signal may be considered not saturated if the absolute value |Δrssi- Δg| of the difference between the signal strength variation value Δrssi and the gain adjustment value Δg does not exceed the preset threshold δ. Otherwise, the first digital signal may be considered to be saturated.

Those skilled in the art will appreciate that the signal strength and gain may be expressed in terms of decibels, but that the operator may be adjusted accordingly.

After the step is performed, if it is determined that the first digital signal has saturation distortion according to the determination result, step 150 is performed; otherwise, the reliability of the first idle channel assessment result is higher, and the first idle channel assessment result can be used as a channel busy state judgment result.

In step 150, a second idle channel assessment is performed based on the second digital signal, and the second idle channel assessment result is used as a channel busy state determination result.

Step 150 may be further broken down into the following steps 151 to 153, as shown in fig. 5.

In step 151, a triggering manner of the first idle channel assessment result is determined.

The first CCA may employ one or both of an energy detection scheme and a carrier sense scheme. In the present disclosure, the triggering manner of the first clear channel assessment result refers to a CCA manner corresponding to the first CCA result. If both modes are adopted at the same time, one CCA mode can be arbitrarily selected, or the CCA mode with the earlier output result is used as the triggering mode of the first CCA.

If the first CCA is triggered by the energy detection mode, then step 152 is performed; if the first CCA is triggered by carrier sensing, step 153 is performed.

In step 152, the second signal strength is compared with the second energy detection threshold, and the channel state is determined based on the comparison result.

If the second signal strength RSSI ₂ Greater than a second energy detection threshold gamma ₂ And judging the channel state as busy, otherwise, judging the channel state as idle.

It should be noted that the first signal strength RSSI ₁ Is calculated from the first digital signal and the second signal strength RSSI ₂ Is calculated by the second digital signal, and the first energy detection threshold gamma is set because the corresponding receiver gains of the first digital signal and the second digital signal are different ₁ And a second energy detection threshold gamma ₂ The difference in receiver gain should be taken into account when. Wherein the first energy detection threshold gamma ₁ An energy detection threshold is used for the first CCA in an energy detection mode.

And a second energy detection threshold gamma ₂ Can be set as a first energy detection threshold gamma ₁ Difference from gain adjustment value ΔG, i.e. gamma ₂ ＝γ ₁ –ΔG。

In some embodiments, to increase the probability of channel busy detection, a second energy detection threshold γ ₂ May be set to be less than the first energy detection threshold gamma ₁ Difference from gain adjustment value ΔG, i.e. gamma ₂ <γ ₁ –ΔG。

In some embodiments, to reduce the false alarm probability of the channel being busy, a second energy detection threshold γ ₂ May be set to be greater than the first energy detection threshold gamma ₁ Difference from gain adjustment value ΔG, i.e. gamma ₂ >γ ₁ –ΔG。

In step 153, a carrier sense method is used to detect whether the second digital signal includes the second sequence, and the channel state is determined based on the detection result.

If the second sequence is detected to be contained in the second digital signal, the channel state is judged to be busy, otherwise, the channel state is judged to be idle.

In the prior art, CCA may be performed by detecting whether a received signal contains a characteristic sequence, which is a sequence contained in a signal transmitted by another device, and may be generally determined according to a communication protocol used by the communication device. In addition, as shown in fig. 4, a communication protocol typically requires that a CCA be completed within a prescribed CCA time window, and in accordance with the methods of the present disclosure, the protocol prescribed CCA time window includes a first CCA time window and a second CCA time window, and thus, in the present disclosure, both the first CCA time window and the second CCA time window are less than the CCA time window prescribed by the communication protocol, or less than the CCA time of a legacy receiver using the communication protocol. In the present disclosure, CCA is performed with a first sequence as a feature sequence in a first CCA time window, and CCA is performed with a second sequence as a feature sequence in a second CCA time window. The first sequence and the second sequence may be part of a signature sequence used by the legacy receiver, for example, a former part of the signature sequence used by the legacy receiver may be taken as the first sequence, and a remaining latter part as the second sequence.

The length of the first sequence and the length of the second sequence may be reasonably determined according to the lengths of the first CCA time window and the second CCA time window. In some embodiments, the length of the first sequence may be greater than or equal to the length of the second sequence. In other embodiments, the length of the first sequence may be less than the length of the second sequence.

It should be noted that the steps 152 and 153 are independent, and the two steps are not sequential in execution time, and which step is executed depends on the triggering manner of the first CCA. After any step is executed, the channel busy/idle state judgment result can be output.

After the method 100 is performed, a channel busy state evaluation result may be obtained. If the channel is busy, the communication device executes the corresponding operation when the channel state is busy, otherwise, executes the corresponding operation when the channel state is idle. The corresponding operation is executed according to the busy state of the channel, and the implementation method same as that of the receiver in the prior art can be adopted, so that the description is omitted.

The present disclosure also provides a channel busy state assessment apparatus, fig. 6 is an exemplary block diagram of a channel busy state assessment apparatus 200 according to an embodiment of the present disclosure, and the apparatus 200 may be used to implement the channel busy state assessment method 100 of the present disclosure. As shown in fig. 6, the apparatus 200 includes a receiving unit 210, a first CCA unit 220, a gain adjusting unit 230, a saturation distortion judging unit 240, and a second CCA unit 250. The structure of the units of the apparatus 200 and the operation thereof will be briefly described with reference to the accompanying drawings, and for further details, reference may be made to the description of the channel busy state evaluation method 100.

The receiving unit 210 is configured to receive the air interface signal with a first gain in a first time interval and output a first digital signal, and receive the air interface signal with a second gain in a second time interval, so as to obtain a second digital signal, where the second gain is smaller than the first gain.

The first CCA unit 220 is configured to perform a first clear channel assessment based on the first digital signal, and output a first clear channel assessment result.

The gain adjustment unit 230 is configured to set the receiving unit 210 to receive the air interface signal with the second gain for the second time interval in response to the first clear channel assessment result being that the channel is busy.

The saturation distortion judging unit 240 is configured to judge whether or not the first digital signal has saturation distortion, and output the judgment result.

Fig. 7 shows an exemplary block diagram of the saturation distortion judging unit 240. As shown in fig. 7, the saturation distortion judging unit 240 includes a signal strength variation value calculating module 241, a gain adjustment value calculating module 242, a difference calculating module 243 between the signal strength variation value and the gain adjustment value, and a threshold comparing module 244.

The signal strength variation value calculating module 241 is configured to calculate a difference between the signal strength of the first digital signal and the signal strength of the second digital signal, so as to obtain a signal strength variation value.

The gain adjustment value calculation module 242 is configured to calculate a difference between the first gain and the second gain to obtain a gain adjustment value.

The difference calculating module 243 is used for calculating the absolute value of the difference between the signal strength variation value and the gain adjustment value.

The threshold comparison module 244 is configured to compare whether the absolute value of the difference between the signal strength variation value and the gain adjustment value exceeds a preset threshold, and if the absolute value does not exceed the threshold, to confirm that the first digital signal is not saturated; otherwise, if the threshold is exceeded, confirming that saturation distortion exists in the first digital signal.

The second CCA unit 250 is configured to perform a second clear channel assessment based on the second digital signal in response to the first digital signal having saturation distortion, and to use the second clear channel assessment result as a channel busy state decision result.

The present disclosure also provides an electronic device comprising a receiver, a memory and a processor, which may be used to implement the aforementioned channel busy state evaluation method 100. The receiver is configured to receive the air interface signal under the control of the processor and obtain a digital signal; the memory is used to store instructions executable by the processor that, when executed by the processor, perform the operations of the steps of the channel busy state evaluation method 100.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art from a reading of the specification, the disclosure, and the drawings, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the terms "a" and "an" do not exclude a plurality. In the practice of the present application, one part may perform the functions of a plurality of technical features recited in the claims. Any reference signs in the claims shall not be construed as limiting the scope.

Claims (12)

1. A method for channel busy state assessment, the method comprising:

receiving an air interface signal by adopting a first gain in a first time interval to obtain a first digital signal;

performing first idle channel assessment based on the first digital signal to obtain a first idle channel assessment result;

receiving an air interface signal by adopting a second gain in a second time interval to obtain a second digital signal in response to the first idle channel estimation result that the channel is busy, wherein the second gain is smaller than the first gain;

judging whether saturation distortion exists in the first digital signal or not; and

and responding to the first digital signal with saturation distortion, performing second idle channel assessment based on the second digital signal, and taking the second idle channel assessment result as a channel busy/idle state judgment result.

2. The method of claim 1, wherein determining whether saturation distortion exists for the first digital signal comprises:

judging whether the absolute value of the difference between a signal strength change value and a gain adjustment value exceeds a preset threshold, wherein the signal strength change value is the difference between the signal strength of the first digital signal and the signal strength of the second digital signal, and the gain adjustment value is the difference between the first gain and the second gain;

and confirming that saturation distortion exists in the first digital signal in response to the absolute value of the difference between the signal strength variation value and the gain adjustment value exceeding a preset threshold.

3. The method according to claim 2, wherein the method further comprises:

confirming that no saturation distortion exists in the first digital signal in response to the absolute value of the difference between the signal strength variation value and the gain adjustment value not exceeding a preset threshold;

and taking the first idle channel evaluation result as a channel busy state judgment result.

4. The method of claim 1 wherein performing a second clear channel assessment based on the second digital signal and using the second clear channel assessment result as a channel busy state decision result comprises:

if the first idle channel assessment result is triggered based on an energy detection mode, comparing the second signal strength with a second energy detection threshold;

and in response to the second signal strength being greater than the second energy detection threshold, determining that the channel state is busy, otherwise determining that the channel state is idle.

5. The method of claim 4, wherein the first clear channel assessment uses a first energy detection threshold for energy detection, and wherein the second energy detection threshold is greater than or equal to a difference between the first energy detection threshold and the gain adjustment value, the gain adjustment value being a difference between the first gain and the second gain.

6. The method of claim 1 wherein performing a second clear channel assessment based on the second digital signal and using the second clear channel assessment result as a channel busy state decision result comprises:

if the first idle channel assessment result is triggered based on a carrier sense mode, detecting whether the second digital signal contains a second sequence or not by adopting the carrier sense mode;

and in response to detecting the second sequence, judging that the channel state is busy, otherwise, judging that the channel state is idle.

7. The method of claim 6, wherein the first clear channel assessment uses a first sequence for carrier sensing, the first sequence having a length that is greater than or equal to a length of the second sequence.

8. The method of claim 1, wherein prior to receiving the air interface signal with the second gain, the method further comprises:

determining a gain reduction value based on a signal strength of the first digital signal;

subtracting the gain reduction value from the first gain to obtain the second gain.

9. The method of claim 1, wherein the length of the first time interval is greater than the length of the second time interval.

10. A channel busy state evaluation apparatus, the apparatus comprising:

the receiving unit is configured to receive the air interface signal by adopting a first gain in a first time interval, output a first digital signal, and receive the air interface signal by adopting a second gain in a second time interval when the channel is busy as a result of the first idle channel assessment, so as to obtain a second digital signal, wherein the second gain is smaller than the first gain;

a first clear channel assessment unit configured to perform a first clear channel assessment based on the first digital signal, and output the first clear channel assessment result;

a gain adjustment unit configured to set the receiving unit to receive a null signal at the second gain during the second time interval in response to the first clear channel assessment result being that the channel is busy;

a saturation distortion judging unit configured to judge whether saturation distortion exists in the first digital signal; and

and a second clear channel assessment unit configured to perform a second clear channel assessment based on the second digital signal in response to the first digital signal having saturation distortion, and to use the second clear channel assessment result as a channel busy state determination result.

11. The apparatus according to claim 10, wherein the saturation distortion judging unit includes:

a signal strength variation value calculation module configured to calculate a difference between the signal strength of the first digital signal and the signal strength of the second digital signal, resulting in a signal strength variation value;

a gain adjustment value calculation module configured to calculate a difference between the first gain and the second gain, resulting in a gain adjustment value;

a difference calculation module of a signal strength variation value and a gain adjustment value configured to calculate an absolute value of a difference between the signal strength variation value and the gain adjustment value; and

and the threshold comparison module is configured to compare whether the absolute value of the difference between the signal strength variation value and the gain adjustment value exceeds a preset threshold, if the absolute value does not exceed the preset threshold, the first digital signal is confirmed to have no saturation distortion, and otherwise, the first digital signal is confirmed to have the saturation distortion.

12. An electronic device, comprising: receiver, memory and processor, wherein

The receiver is configured to receive an air interface signal under the control of the processor and obtain a digital signal;

the memory stores instructions executable by the processor, the instructions causing the processor to perform the steps of:

controlling the receiver to receive an air interface signal by adopting a first gain in a first time interval to obtain a first digital signal;

performing first idle channel assessment based on the first digital signal to obtain a first idle channel assessment result;

responding to the first idle channel estimation result to be that the channel is busy, and controlling the receiver to receive an air interface signal in a second time interval by adopting a second gain to obtain a second digital signal;

judging whether saturation distortion exists in the first digital signal or not;

and responding to the first digital signal with saturation distortion, performing second idle channel assessment based on the second digital signal, and taking the second idle channel assessment result as a channel busy/idle state judgment result.

Images