JP2019106671A - Interference detection method of radio signal - Google Patents

Abstract

To achieve a function for determining where an error factor occurred on a radio transmission path is caused by an interference by using a simple system.SOLUTION: When one or more pause sections Tp1 to Tp3 is assigned to a continuous frame structure F2 of a radio signal transmitted from a radio transmitter, the transmission from the radio transmitter is temporally stopped in each pause section, and the radio signal received by the radio transmitter is processed, an interruption between a target radio signal and the other radio signal is detected on the basis of a state of the radio signal received at a timing of the pause sections Tp1 to Tp3. In the case where an interruption wave shorter than the frame to be received after the start of the transmission appears, the interruption wave can be detected at the timing of the pause sections in the middle of the transmission. By adapting the special frame structure F2, the execution of a complex control or addition of an expensive hardware is not required. Long data is divided and the pause section Tp2 is arranged in a boundary.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for detecting interference of wireless signals.

  If the other party can not detect that there is a radio wave, such as a hidden terminal problem, or if the communication method is different from the CSMA method, the communication collides. In such a case, interference of a plurality of wireless signals causes the wireless receiver to fail to receive a wireless signal from a target wireless transmitter or causes deterioration in communication quality. Therefore, a technique for detecting the interference of a plurality of wireless signals is required.

  For example, in the wireless communication system of Patent Document 1, in order to distinguish between interference within its own system and interference from other systems, packetization is performed by adding a CRC to each unit block of data on the transmission side. There is. Also, on the reception side, the correlation between the incorrect unit block preamble and the correct preamble is detected, and if there is a correlation, it is judged as interference within its own system, and from the other systems if there is no correlation.

  On the other hand, in the general communication protocol CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance), before starting communication, whether there is another host currently communicating by attempting reception once. Confirm (carrier sense). Also, a plurality of clients share the same line, and if other parties are not communicating, they start their own communication. Furthermore, in order to avoid collisions, when detecting the end of transmission of another host, it takes a random length of waiting time before it starts transmission.

JP, 2016-21634, A

  However, in the case of CSMA / CA, if an error occurs in the received data on the receiving side of the wireless signal, whether the cause is due to interference of a plurality of transmission radio waves or deterioration of the radio wave environment of the transmission path It is difficult to distinguish.

  For example, when an error occurs in received data due to interference of radio waves, the frequency channel of radio waves used by the wireless transmitter for transmission is switched to avoid occurrence of radio wave interference, and errors in received data are made. It can be reduced. On the other hand, when an error occurs in the received data due to deterioration of the radio wave environment of the transmission path, the error of the received data can not be reduced even if the radio transmitter switches the frequency channel of the radio wave used for transmission. Therefore, when an error occurs in the received data, it is very important to distinguish whether the cause is due to the interference of a plurality of transmission radio waves or the deterioration of the radio wave environment of the transmission path.

  For example, by employing the technology of Patent Document 1, when interference occurs, it is possible to distinguish between interference within the own system and interference from other systems. However, it is not possible to distinguish between interference from other systems and deterioration of the radio wave environment of the transmission path. In addition, a preamble correlator is required, which increases the complexity of hardware or software, resulting in an expensive wireless terminal. Also, there is a problem that the very short interference generated in the packet can not be detected because it does not affect the preamble.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to use a simple system for determining whether the cause of an error generated on a wireless transmission channel is an error due to interference or not. It is an object of the present invention to provide an interference detection method for radio signals that can be realized.

In order to achieve the above-mentioned object, the interference detection method for a radio signal according to the present invention is characterized by the following (1) to (5).
(1) A wireless signal interference detection method for detecting interference in the wireless signal when the wireless receiver receives a wireless signal transmitted from a predetermined wireless transmitter,
Assign one or more pause intervals in a series of frame configurations of the wireless signal transmitted by the wireless transmitter,
In the idle period, the transmission of the wireless transmitter is temporarily stopped,
When processing a wireless signal received by the wireless receiver, interference between the wireless signal from the wireless transmitter and another wireless signal is detected based on at least the state of the wireless signal received at the timing of the pause period. Do,
A method of detecting interference of a wireless signal, comprising:

  According to the interference detection method of the wireless signal of the configuration of the above (1), it can be easily determined whether the cause of the error generated on the wireless transmission path is an error due to interference. That is, when the wireless receiver monitors the state of the wireless signal on the transmission path, the target wireless signal does not exist at the timing of the idle period, so that interference occurs in a short time shorter than the frame of the wireless signal to be received. Even if it is, the presence or absence of the radio signal from the interference source can be detected reliably and easily. In addition, since a pause period is allocated in the frame structure, even if a new interference source appears after the wireless transmitter starts transmitting a wireless signal, the cause of an error in the received data of the wireless receiver is Whether it is an error due to interference can be easily determined.

(2) The pause period is assigned to at least one of the front, middle and back of the transmission data area included in the frame configuration.
A method of detecting interference of a radio signal according to the above (1), characterized in that

  According to the method of detecting interference of radio signals in the configuration of (2), the presence or absence of radio signals from the interference source can be detected at timing adjacent to the transmission data area, so radio signals from interference sources are intermittently transmitted. Even in such a case, it is possible to more accurately determine whether the cause of the error generated on the wireless transmission channel is an error due to interference.

(3) The wireless receiver performs carrier sensing of a wireless signal at least at the timing of the idle period, and uses the result of comparing the carrier reception level obtained by the carrier sensing with a threshold value to determine the presence or absence of interference.
A method for detecting interference of a radio signal according to the above (1) or (2), characterized in that

  According to the method of detecting interference of radio signals in the configuration of (3), it is possible to detect the presence or absence of an interference wave having a large influence which actually causes an error in reception of a target radio signal. It is possible to more accurately determine whether the cause of the error is an error due to interference.

(4) The wireless receiver determines the presence or absence of interference when detecting an error in received data extracted from a received wireless signal, and performs control for avoiding the interference only in the presence of interference.
A radio signal interference detection method according to any one of the above (1) to (3), characterized in that

  According to the wireless signal interference detection method of the configuration of (4), when an error occurs in the received data in the wireless receiver, control for reducing the error can be automatically implemented. That is, it is possible to selectively implement appropriate control for reducing data errors by using the result of determining whether the cause of error is interference or not.

(5) In the case where the wireless transmitter transmits one or more consecutive data of a predetermined length or more using one of the frame configurations, the data is divided into a plurality of data, and the boundaries of the plurality of divided data are divided. Assign the pause interval to a position,
A method of detecting interference of a radio signal according to the above (2), characterized in that

  According to the wireless signal interference detection method of the above configuration (5), the pause period is allocated to the boundary position of the plurality of divided data, so that the wireless signal from the interference source appears intermittently for a short time. Even if this is the case, the possibility of being able to detect the presence or absence of an interference wave at the timing of the pause period is increased.

  According to the method of detecting interference of a wireless signal of the present invention, it is possible to easily determine whether the cause of an error generated on a wireless transmission channel is an error due to interference and interference can be avoided even with a simple system. .

  The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the modes for carrying out the invention described below (hereinafter referred to as "embodiments") with reference to the attached drawings. .

FIG. 1 is a block diagram showing a configuration example of a wireless communication system to which the present invention is applied. 2 (a) and 2 (b) are schematic diagrams showing the frame configuration of a radio signal to be transmitted, and FIG. 2 (a) is a general configuration example, and FIG. 2 (b) is the case where the present invention is applied. Each of the configuration examples of FIG. 3 is a block diagram showing an example of the configuration of a wireless receiver used when practicing the present invention. FIG. 4 is a flow chart showing an example of processing carried out by the wireless receiver to determine the presence or absence of interference when the present invention is implemented. FIG. 5 is a sequence diagram showing an operation example of the wireless communication system when the present invention is implemented.

  Specific embodiments of the present invention are described below with reference to the figures.

<Configuration Example of Wireless Communication System>
A configuration example of a wireless communication system to which the present invention is applied is shown in FIG.

  The wireless communication system shown in FIG. 1 includes a wireless transmitter 10 for transmitting a wireless signal (radio wave) W1 and a wireless receiver 20 capable of receiving the wireless signal W1. Moreover, the case where the interference source 15 which transmits the radio signal W2 used as an interference wave in the vicinity is assumed is assumed.

  The wireless communication system shown in FIG. 1, for example, is assumed to be mounted on a vehicle and used for communication on the vehicle by mounting the wireless transmitter 10 and the wireless receiver 20 on the vehicle. Of course, the present invention can also be used when communicating in various places other than on the vehicle.

  In practice, a number of wireless communication terminals having the wireless transmitter 10 and the wireless receiver 20 are installed in various places on the vehicle in a distributed state, and transmit and receive wireless signals among a plurality of wireless communication terminals. It is assumed that The interference source 15 may be part of a wireless communication system on the vehicle or may be outside the vehicle. In addition, there may be a large number of interference sources 15 in a dispersed state.

  In the situation as shown in FIG. 1, for example, when the wireless transmitter 20 and the interference source 15 transmit the wireless signals W1 and W2 using the same frequency channel at substantially the same timing, when the wireless receiver 20 receives these signals, Interference of the wireless signals W1 and W2 occurs. As a result, an error occurs in the received data in the wireless receiver 20.

  On the other hand, even in the situation where interference of the wireless signals W1 and W2 does not occur, for example, when an obstacle appears in the space between the wireless transmitter 10 and the wireless receiver 20, various frequencies When noise including a component is generated, deterioration of the transmission path between the wireless transmitter 10 and the wireless receiver 20 causes an error in received data in the wireless receiver 20.

  That is, as a cause of the occurrence of an error in the received data in the wireless receiver 20, the interference of the plurality of wireless signals W1 and W2 and the deterioration of the transmission path can be considered. In the case of interference of a plurality of wireless signals W1 and W2, interference can be avoided by switching the frequency of the wireless channel used by the wireless transmitter 10 for transmitting the wireless signal W1. However, when an error occurs due to the deterioration of the transmission path, even if the frequency of the wireless channel used to transmit the wireless signal W1 is switched, the error in the received data in the wireless receiver 20 can not be improved. Therefore, when an error occurs in the received data in the wireless receiver 20, it is important to be able to distinguish between the interference of the plurality of wireless signals W1 and W2 and the deterioration of the transmission path.

  For example, when using CSMA / CA, which is a general communication protocol, since the wireless transmitter 10 performs carrier sensing before starting transmission of the wireless signal W1, the wireless from the interference source 15 is transmitted. The presence or absence of the signal W2 can be confirmed before transmission. Therefore, the interference of the plurality of wireless signals W1 and W2 can be avoided. However, for example, in the case where the generation of the wireless signal W2 from the interference source 15 is intermittent or only for a short time shorter than the frame of the wireless signal W1, the wireless signal is transmitted by carrier sense before the start of transmission of the wireless transmitter 10. W2 can not be detected. Therefore, after the wireless transmitter 10 starts transmission of the wireless signal W1, interference of the plurality of wireless signals W1 and W2 occurs, and an error occurs in the reception data of the wireless receiver 20. In such a case, the general method can not identify whether the cause of the error is interference or degradation of the transmission path.

<Example of frame configuration of wireless signal>
The frame configuration of the radio signal to be transmitted is shown in FIGS. 2 (a) and 2 (b). FIG. 2A shows a general configuration example, and FIG. 2B shows a configuration example to which the present invention is applied. In FIG. 2A and FIG. 2B, the horizontal axis represents time t, and it is assumed that it changes from left to right with the passage of time t.

  In the general frame F1 shown in FIG. 2A, the preamble PR, the unique word UW, the control parameter information CONT, and the data area DATA are continuously arranged in the order of times t1, t2, t3 and t4. It is configured. Usually, the data length of, for example, about several tens of bits is obtained for all of PR, UW, and CONT. When CSMA / CA is used, the wireless transmitter performs carrier sense at time t0 before transmission of this frame F1 is started.

  Here, the preamble PR is a signal used for synchronization for adjusting the timing on the receiving side to the transmitting side. The unique word UW is a signal used to distinguish between a wireless terminal belonging to the own system and a wireless terminal of another system. The control parameter information CONT is a signal used to store parameters necessary for communication control, such as a data length (LD0) to be transmitted, for example. The content of the data transmitted by the wireless transmitter is stored in the data area DATA.

  On the other hand, in the case of practicing the present invention, for example, the frame F2 as shown in FIG. 2 (b) is used. This frame F2 contains, like the frame F1, a continuous preamble PR, a unique word UW, and control parameter information CONT.

  In the frame F2, the pause interval Tp1 is disposed immediately after the control parameter information CONT, and the data area DATA1 is disposed after the pause interval Tp1. Furthermore, a pause section Tp2 is disposed immediately after the data area DATA1, and a data area DATA2 is disposed after the pause section Tp2. Furthermore, a pause interval Tp3 is disposed immediately after the data area DATA2.

  Each of the three pause periods Tp1 to Tp3 is a period in which the radio transmitter 10 temporarily stops transmission of a radio signal (carrier wave). The time length of each pause interval Tp1 to Tp3 is a relatively short time, and is determined based on, for example, a predetermined constant. These idle periods Tp1 to Tp3 are used for the wireless receiver 20 to detect a wireless signal (W2) from an interfering source (15) that interferes while transmitting the frame F2. That is, since the wireless transmitter 10 does not output a wireless signal in each pause period Tp1 to Tp3, the presence or absence of the interfering wireless signal (W2) can be easily detected. The number of the pause sections Tp1 to Tp3 and the positions at which each is disposed can be changed as necessary.

  In addition, the frame F2 includes two data areas DATA1 and DATA2 with the pause interval Tp2 interposed therebetween. It is assumed that the data area DATA1 is used to store the first half of data transmitted in one frame F2, and the data area DATA2 is used to store the second half of data transmitted in the same one frame F2. Ru.

  For example, when the data length LD0 of data (D0) to be transmitted in one frame F2 is a predetermined length or more, the original data D0 is divided into the first half and the second half, and the first half data D1 is stored in the data area DATA1. , The second half data D2 is stored in the data area DATA2. As a result, since the data lengths LD1 and LD2 become short, it is possible to avoid an increase in the time interval at which each pause interval Tp1 to Tp3 occurs. That is, even when the interfering wireless signal W2 is intermittent or shorter than the frame F1, the carrier sense of the wireless receiver 20 at any timing of each pause period Tp1 to Tp3 causes the presence of the wireless signal W2 Can detect the presence or absence of

  Note that, in order to avoid timing deviation when the data length becomes long, for example, the preamble PR may be added to the head position of the data area DATA2. Also, the data lengths LD1 and LD2 do not have to be the same. Further, the number of divisions of the data areas DATA1 and DATA2 may be increased to three or more.

  In the case of practicing the present invention, for example, the radio receiver 20 shown in FIG. 1 receives the frame F2 configured as shown in FIG. 2 (b). Therefore, by performing carrier sensing at each timing of the pause period Tp1 to Tp3, for example, the wireless receiver 20 can determine the presence or absence of the interfering wireless signal W2 and the reception level thereof, that is, the presence or absence of interference. It is assumed that the timing of the pause period Tp1 to Tp3 is determined in advance as a constant for each system. That is, the wireless receiver 20 belonging to the same system as the wireless transmitter 10 can treat the timing of the pause period Tp1 to Tp3 in the frame F2 transmitted by the wireless transmitter 10 as a known parameter based on a constant. Further, the wireless receiver 20 can distinguish whether the corresponding wireless transmitter 10 belongs to the own system by referring to the unique word UW included in the received frame F2.

<Configuration Example of Wireless Receiver 20>
An exemplary configuration of the wireless receiver 20 used when practicing the present invention is shown in FIG.
The radio receiver 20 shown in FIG. 3 receives the radio signal of the frame F2 as shown in FIG. 2 (b). Then, at the timing of each pause interval Tp1 to Tp3 included in the received wireless signal, the reception level fluctuates according to the presence or absence of the interference wave and the level of the interference wave. Therefore, as a characteristic function, the wireless receiver 20 has a function of detecting the reception level fluctuation of the carrier wave at the timing including the pause periods Tp1 to Tp3.

  The radio receiver 20 shown in FIG. 3 includes a reception antenna 21, a detection unit 22, a reception processing unit 23, an envelope detection unit 24, a level fluctuation detection unit 25, a pattern detection unit 26, a data reception determination unit 27, and an interference determination unit. It has 28.

  The receiving antenna 21 can receive a wireless signal (radio wave) of a frame configuration as shown in FIG. 2B transmitted from the wireless transmitter 10. The detection unit 22 receives the reception signal SG21 from the reception antenna 21, detects this, and outputs a detection output signal SG22. The reception processing unit 23 can process the detection output signal SG22 to output reception data SG23.

  The envelope detection unit 24 can receive the reception signal SG21 from the reception antenna 21 and detect the envelope, and can output the reception level signal SG24 as a time-series signal representing the amplitude of the envelope at each time point. . That is, a signal representing the reception level fluctuation of the carrier wave in the radio signal of the frame configuration as shown in FIG. 2B is output from the envelope detection unit 24. For example, when there is no interference wave, the reception level in each pause period Tp1 to Tp3 is minimized.

  The level fluctuation detection unit 25 receives the reception level signal SG24, and, for example, the level fluctuation signal SG25 representing the time-dependent change of the difference between the amplitude of each of the idle periods Tp1 to Tp3 and the amplitude of the other periods or the ratio thereof. It can be output.

  The pattern detection unit 26 can detect a predetermined fluctuation pattern determined in advance from the input level fluctuation signal SG25. For example, as in the case where no interference wave is present, a fluctuation pattern is detected such that the drop of the reception level in all the pause periods Tp1 to Tp3 is a predetermined level or more. Also, as in the case where an interference wave of the same level as the target radio signal appears for a long time, a fluctuation pattern is also detected in which the reception level hardly appears in any of the pause periods Tp1 to Tp3. Do. Furthermore, as in the case where the interference wave appears for a short time shorter than the frame of the target radio signal, a fluctuation pattern is also detected in which a drop in reception level hardly appears in at least one of the pause periods Tp1 to Tp3.

  In addition, it is possible to determine the presence or absence of interference without necessarily detecting the specific fluctuation pattern as described above. That is, the simplest method is to compare the reception level signal SG24 or the level fluctuation signal SG25 with a predetermined threshold value, and when the reception level exceeds the threshold value in at least one of the pause periods Tp1 to Tp3: It can be determined that there is interference. In addition, when the reception level is less than the threshold value in all the pause periods Tp1 to Tp3, it can be determined that there is no interference.

  The data reception determination unit 27 determines whether the reception processing of the reception processing unit 23 is successful and the correct reception data SG23 is obtained or whether the quality of the transmission path is not deteriorated based on the packet error rate of the reception data. It has a function for determination, and outputs a reception determination result SG27.

  The interference determination unit 28 determines the presence or absence of interference between the target wireless signal and the other wireless signals based on the variation pattern detection result SG26 and the reception determination result SG27, and outputs the interference determination result SG28. Have.

<Process for Wireless Receiver 20 to Determine Presence of Interference>
An example of processing performed by the wireless receiver 20 to determine the presence or absence of interference when the present invention is implemented is shown in FIG. The process of FIG. 4 will be described below.

The wireless receiver 20 starts to receive an incoming radio wave using the receiving antenna 21 (S11).
The detection unit 22 in the wireless receiver 20 performs data detection of the reception signal SG21 from the reception antenna 21, and the reception processing unit 23 demodulates the detected data (S14).

  At the same time, the envelope detection unit 24 performs envelope detection of the reception signal SG21 from the reception antenna 21 and outputs a reception level signal SG24 representing the reception level (amplitude) of the carrier wave of the radio wave (S12).

  Further, the level fluctuation detection unit 25 detects the level fluctuation of the reception level signal SG24, and the pattern detection unit 26 detects a specific fluctuation pattern. That is, a specific pattern is detected based on the carrier sensing result of each timing including each transmission pause period Tp1 to Tp3 (S13).

  On the other hand, the data reception determination unit 27 monitors the reception data SG23 output from the reception processing unit 23, and outputs a reception determination result SG27. The reception determination result SG27 indicates, for example, whether or not there is an error in the received data. If there is no error in the received data, the process proceeds from S15 to S16. If there is an error in the received data, the process proceeds from S15 to S17.

  If there is an error in the received data, the interference determination unit 28 identifies the presence or absence of interference (S17). That is, since the fluctuation pattern detection result SG26 output from the pattern detection unit 26 reflects the presence or absence of the interference wave in the pause period Tp1 to Tp3 of the received frame F2 and the magnitude of the influence of the interference wave, the interference judgment unit 28 can identify the presence or absence of interference based on fluctuation pattern detection result SG26. When there is an error in the received data, the interference determination unit 28 outputs the interference determination result SG28 (S18).

  If the data reception determination unit 27 determines that there is no error in the received data, the reception processing unit 23 regards the normal reception state and continues the reception process (S16). Therefore, the terminal connected to the wireless receiver 20 can obtain the correct reception data SG23 from the output of the reception processing unit 23.

<Operation Example of Wireless Communication System>
An operation example of the wireless communication system in the case of implementing the present invention is shown in FIG. The operation of FIG. 5 will be described below.

  When errors in received data in the wireless receiver 20 are increased due to the deterioration of the transmission path or the influence of interference waves, it is necessary to prevent the deterioration of the communication quality. If the transmission path is degraded, it is possible to reduce errors in the received data, for example, by reducing the communication speed. In addition, when an error occurs in received data due to the influence of an interference wave, it is possible to avoid interference by switching the frequency of a communication channel used for transmission of a radio signal. It is possible to reduce However, when the transmission line itself is degraded, switching the frequency of the communication channel to be used has no effect. Therefore, when an error occurs in the received data, if it can be distinguished whether the cause is interference or not, effective control can be selectively performed according to the difference in the cause.

  In the example shown in FIG. 5, it is assumed that wireless communication terminals 31 and 32 are included in the same wireless communication system, and wireless communication is performed between them. The wireless communication terminal 31 has a receiving function in addition to the transmitting function corresponding to the wireless transmitter 10 shown in FIG. 1, and the wireless communication terminal 32 has a transmitting function in addition to the receiving function corresponding to the wireless receiver 20. ing.

  The wireless communication terminal 31 determines the frequency of the communication channel used for transmission in S21 and starts transmission. That is, communication data is transmitted by a wireless signal using the transmission function of the wireless transmitter 10.

  The wireless communication terminal 32 starts receiving the communication data of the wireless signal transmitted from the wireless communication terminal 31 in S22. Further, the wireless communication terminal 32 detects an error in the received communication data in S23. Further, since the wireless communication terminal 32 includes the function of the wireless receiver 20, it is possible to obtain the interference determination result SG28 indicating the presence or absence of interference.

  When the reception error of communication data occurs in the wireless communication terminal 32 due to the occurrence of interference, the wireless communication terminal 32 proceeds from the process of S24 to the process of S25. Then, using the transmission function, the wireless communication terminal 32 transmits the determination result including the information with interference by a wireless signal.

  The wireless communication terminal 31 recognizes that the interference is occurring by receiving the wireless signal including the information with interference transmitted from the wireless communication terminal 32 using the reception function. Then, in order to avoid this interference, the wireless communication terminal 31 changes the frequency of the communication channel used for transmission to another frequency (S26).

  Then, the wireless communication terminal 31 continues transmission of communication data using the communication channel of the changed frequency. When the wireless communication terminal 31 switches the frequency in S26, the changed frequency may be notified to the wireless communication terminal 32, and transmission of communication data may be resumed thereafter.

  When the radio communication terminal 31 changes the frequency of the communication channel used for transmission, the radio communication terminal 32 continues the reception process at the changed frequency (S27). When it is not determined that there is interference in the wireless communication terminal 32, and it is found that a reception error occurs due to the deterioration of the transmission path, the processing of S25, S26, and S27 is not performed. That is, in that case, the communication channel of the same frequency is used as it is. However, in this case, for example, information indicating the degree of degradation of the transmission path may be transmitted from the wireless communication terminal 32 to the wireless communication terminal 31, and the wireless communication terminal 31 may be controlled to lower the communication speed.

  Further, in the operation example of FIG. 5, there is shown a case where the radio communication terminal 32 on the receiving side notifies the radio communication terminal 31 on the transmitting side of the information with interference, but instead, a request for frequency change is given. May be transmitted to the wireless communication terminal 31 by the wireless communication terminal 32.

<Possibility of modification other than the above>
In the above-described wireless communication system, it is assumed that CSMA / CA is used as a basic communication protocol, but another communication protocol such as TDMA (Time Division Multiple Access) is used. The present invention is also applicable. When TDMA is employed, for example, the carrier sense at time t0 shown in FIGS. 2A and 2B disappears.

<Advantages of Wireless Communication System>
In the above-described wireless communication system, one or more pause intervals Tp1 to Tp3 are allocated in the middle of the frame F2 transmitted by the wireless transmitter 10, and the wireless transmitter 10 pauses transmission of the wireless signal at the timing of each pause interval. . Therefore, the wireless receiver 20 can easily grasp the presence / absence of the interference wave and the level thereof at the timing of each pause interval Tp1 to Tp3 and can reliably determine whether the cause of the generated reception data error is due to interference or not. .

  Also, when the radio wave of the interference wave transmitted by the interference source 15 is intermittent or only a short time shorter than the frame to be received, only the carrier sense before transmission (time t0) in CSMA / CA There is a possibility that interference can not be avoided. However, in the case of the above-described wireless communication system, since the interference wave can be detected at each timing of the pause period Tp1 to Tp3 provided in the frame F2, it is determined whether the cause of the error is interference or not and interference is avoided. Control can be implemented.

  In addition, since interference waves are detected using the devised frame F2 including the pause periods Tp1 to Tp3, interference avoidance can be achieved with a simple system without the need to perform complicated control or add expensive hardware. It is possible.

Here, the features of the method for detecting interference of radio signals according to the embodiment of the present invention described above will be briefly summarized and listed in the following [1] to [5].
[1] An interference detection method of a radio signal for detecting interference in the radio signal (W1) when the radio receiver (20) receives a radio signal transmitted from a predetermined radio transmitter (10). ,
One or more pause intervals (Tp1 to Tp3) are allocated in a series of frame (F2) configurations of the wireless signal transmitted by the wireless transmitter,
In the idle period, the transmission of the wireless transmitter is temporarily stopped,
When processing a wireless signal received by the wireless receiver, interference between the wireless signal from the wireless transmitter and another wireless signal is detected based on at least the state of the wireless signal received at the timing of the pause period. (S13, S17),
A method of detecting interference of a wireless signal, comprising:

[2] The pause period is assigned to at least one of the front, middle and rear of the transmission data area (DATA1, DATA2) included in the frame configuration (see FIG. 2 (b)).
The interference detection method of the radio signal as described in said [1].

[3] The wireless receiver performs carrier sensing of a wireless signal at least at the timing of the idle period, and uses the result of comparing the carrier reception level obtained by the carrier sensing with a threshold to determine the presence or absence of interference ((3) S13, S17),
The radio | wireless signal interference detection method as described in said [1] or [2].

[4] When the wireless receiver detects an error in received data extracted from a received wireless signal (S15), it determines the presence or absence of interference (S17), and only in the presence of interference, to avoid the interference. Execute control (S18, operation of FIG. 5),
The radio signal interference detection method according to any one of the above [1] to [3].

[5] The wireless transmitter divides the data into a plurality of (DATA1, DATA2) and transmits the plurality of divided data when transmitting one or more continuous data of a predetermined length or more using one of the frame configurations. The pause interval (Tp2) is assigned to the boundary position of the data in (see FIG. 2 (b)).
The interference detection method of the radio signal as described in said [2].

DESCRIPTION OF SYMBOLS 10 wireless transmitter 15 interference source 20 wireless receiver 21 reception antenna 22 detection unit 23 reception processing unit 24 envelope detection unit 25 level fluctuation detection unit 26 pattern detection unit 27 data reception determination unit 28 interference determination unit 31, 32 wireless communication terminal F1, F2 frame Tp1, Tp2, Tp3 pause interval PR preamble UW unique word CONT control parameter information DATA, DATA1, DATA2 data area LD0, LD1, LD2 data length SG21 reception signal SG22 detection output signal SG23 reception data SG24 reception level signal SG25 level Fluctuation signal SG26 Fluctuation pattern detection result SG27 Reception judgment result SG28 Interference judgment result

Claims (5)

A wireless signal interference detection method for detecting interference in a wireless signal when the wireless signal is received by a wireless receiver when the wireless signal is transmitted from a predetermined wireless transmitter,
Assign one or more pause intervals in a series of frame configurations of the wireless signal transmitted by the wireless transmitter,
In the idle period, the transmission of the wireless transmitter is temporarily stopped,
When processing a wireless signal received by the wireless receiver, interference between the wireless signal from the wireless transmitter and another wireless signal is detected based on at least the state of the wireless signal received at the timing of the pause period. Do,
A method of detecting interference of a wireless signal, comprising: The pause interval is assigned to at least one of the front, middle and back of the transmission data area included in the frame configuration.
The method for detecting interference of a radio signal according to claim 1, characterized in that: The wireless receiver performs carrier sensing of a wireless signal at least at the timing of the idle period, and uses the result of comparing the carrier reception level obtained by the carrier sensing with a threshold to determine the presence or absence of interference.
The interference detection method of the radio signal according to claim 1 or 2 characterized by things. The wireless receiver determines the presence or absence of interference when detecting an error in received data extracted from a received wireless signal, and performs control for avoiding interference only in the presence of interference.
The interference detection method of the radio | wireless signal of any one of the Claims 1 thru | or 3 characterized by the above-mentioned. The wireless transmitter divides the data into a plurality of pieces and transmits the plurality of pieces of data at a boundary position of the plurality of divided pieces of data, when transmitting one or more pieces of continuous data having a predetermined length or more using one of the frame configurations. Assign the pause interval,
The method of detecting interference of a radio signal according to claim 2,

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