Wireless devices, wireless communication methods, and programs

Abstract

To provide a wireless device that enables good communication even in communication environments with high traffic volume. [Solution] The wireless device 10 comprises a monitoring unit 42 and a communication unit 40. The monitoring unit 42 intermittently monitors the radio wave conditions of the communication frequency channel. The communication unit 40 enters a receiving state according to the monitoring results of the monitoring unit 42 and performs the reception of packet signals of the communication frequency channel. The monitoring unit 42 monitors the radio wave conditions of backup frequency channels that are candidates for replacement so as not to overlap with the monitoring period of the communication frequency channel.

Description

Technical Field

[0001] The present disclosure relates to communication technologies, and particularly to wireless devices, wireless communication methods, and programs that use a plurality of frequency channels.

Background Art

[0002] In a power management system, a power meter installed in a house transmits meter reading results to a power company via wireless communication or the like, enabling remote meter reading. The power meter not only performs wireless communication with the power company but also executes wireless communication with electrical appliances installed in the house via a wireless device. Thereby, electrical appliances capable of communicating with the power meter can easily obtain power information measured by the power meter from the power meter, enabling accurate power management.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the number of electronic devices that wirelessly communicate with a wireless device for controlling electronic devices installed in a house increases, signal collisions are likely to occur due to an increase in traffic volume.

[0005] Therefore, the present disclosure has been made to solve such problems, and an object thereof is to provide a wireless device that enables good communication even in a communication environment with a large traffic volume.

Means for Solving the Problems

[0006] A wireless device according to one aspect of this disclosure comprises a monitoring unit and a communication unit. The monitoring unit intermittently monitors the radio wave conditions of a first frequency channel. The communication unit receives packet signals of the first frequency channel. The monitoring unit monitors the radio wave conditions of a second frequency channel, which is a candidate for replacement, so as not to overlap with the monitoring period of the first frequency channel.

[0007] One embodiment of a wireless communication method relating to this disclosure includes a monitoring step and a communication step. The monitoring step intermittently monitors the radio wave conditions of a first frequency channel. The communication step enters a receiving state in accordance with the monitoring results of the monitoring step and performs reception of packet signals on the first frequency channel. The monitoring step monitors the radio wave conditions of a second frequency channel that is a candidate for replacement, so as not to overlap with the monitoring period of the first frequency channel.

[0008] One aspect of the program relating to this disclosure causes a computer system to execute the wireless communication method. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a wireless device that enables good communication even in communication environments with high traffic volume. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a diagram showing the configuration of the communication system according to Embodiment 1. [Figure 2] Figure 2 is a diagram showing the configuration of the wireless device according to Embodiment 1. [Figure 3] Figure 3 shows the procedure for monitoring the frequency channel of the wireless device described above. [Figure 4] Figure 4 is a flowchart showing the frequency channel monitoring and selection procedures for the wireless device mentioned above. [Modes for carrying out the invention]

[0011] The embodiments will be described below with reference to the drawings. The embodiments shown here are all specific examples of the present disclosure. Therefore, the numerical values, shapes, components, arrangement and connection configurations of components, as well as the steps (processes) and the order of steps shown in the following embodiments are examples and are not intended to limit the present disclosure. Accordingly, among the components in the following embodiments, those components that are not described in the independent claims representing the highest-level concept of the present disclosure will be described as arbitrary components. Note that each figure is a schematic diagram and is not necessarily a precise illustration. Therefore, the scale and other aspects in each figure do not necessarily match. Also, in each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0012] (Embodiment 1) Before specifically describing the present invention, an overview will be given. Embodiment 1 of the present invention relates to a wireless device that can use multiple frequency channels for communication. In order to suppress the increase in the circuit size of the wireless device, the number of communication units provided in the wireless device should be "1". In situations where such wireless communication is used, it is necessary to select an appropriate frequency channel in order to not reduce the success rate of communication. When using only one frequency channel, the number of signal collisions increases due to the increase in traffic. When using multiple frequency channels, signal acquisition fails when a signal is received on one frequency channel while a signal is being received on the other frequency channel, or when a signal is received while switching frequency channels. In order to select an appropriate frequency channel, the surrounding radio wave usage should be monitored, but if the transmission and reception process is interrupted to monitor the surrounding environment, there will be a period in which signals cannot be transmitted or received.

[0013] In other words, to suppress the deterioration of the communication success rate, it is necessary to set an appropriate frequency channel, and to set an appropriate frequency channel efficiently, it is necessary to monitor the surrounding environment while minimizing the impact on transmission and reception processing. To this end, the wireless device according to this embodiment intermittently monitors the radio wave conditions of the communication frequency channel that is waiting for packet signals, and when the radio wave conditions of the communication frequency channel are not being monitored, it monitors the radio wave conditions of backup frequency channels that are candidates for switching to the communication frequency channel in the background. Then, based on that information, it switches to an appropriate frequency channel to execute a highly reliable communication system.

[0014] First, the configuration of the communication system 100 according to Embodiment 1 will be explained using Figure 1. Figure 1 is a block diagram showing the configuration of the communication system 100 according to Embodiment 1.

[0015] The communication system 100 includes a wireless device 10, a terminal device 12, a smart meter 16, and a collection control station 18. The wireless device 10, terminal device 12, and smart meter 16 are installed in a house 28. In Figure 1, only one house 28 is shown for clarity, but in reality, there are multiple houses 28, and a smart meter 16, wireless device 10, and terminal device 12 are installed in each house 28.

[0016] The collection control station 18, smart meter 16, wireless device 10, and terminal device 12 are all equipped with wireless communication capabilities. Wireless communication between the collection control station 18 and the smart meter 16 is multi-hop communication 26, and wireless communication between the smart meter 16 and the wireless device 10 is higher-level communication 24. In addition, communication between the wireless device 10 and the terminal device 12 is wireless communication 20.

[0017] (Smart meter) In addition to the aforementioned wireless communication function, the smart meter 16 has a function as a power meter that measures the amount of power used in the house 28. The smart meter 16 is connected to a distribution line (not shown) to which commercial power from an electric power company (electric power business operator) is supplied, and measures the amount of power used in the house 28. The smart meter 16 transmits the meter reading data including the measurement result of the amount of power to the collection control station 18 by multi-hop communication 26. The collection control station 18 corresponds to the master unit of the communication system 100 and receives the meter reading data from the smart meter 16. As a result, remote meter reading by the electric power company becomes possible.

[0018] (Household Electronic Equipment) A terminal device 12 is connected to an electronic device (not shown) installed in the house 28. The electronic devices are, for example, an air conditioner, OA equipment, and a television receiver. The terminal device 12 is compatible with wireless communication 20 and communicates with the wireless device 10. Since the wireless device 10 also communicates with the smart meter 16 by upper-level communication 24, it receives the measurement result from the smart meter 16. Accurate power management of the electronic devices becomes possible based on the measurement result. Hereinafter, since attention is paid to the operation of the wireless device 10, wireless communication 20 and upper-level communication 24 will be the subject of explanation.

[0019] (Wireless Device) The wireless device 10 executes communication with the terminal device 12 and the smart meter 16 by CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance). The wireless device 10 is connected or mounted to a control device that controls an electronic device such as a HEMS (Home Energy Management System) controller, for example.

[0020] (Configuration of Wireless Device) FIG. 2 is a diagram showing the configuration of the wireless device 10. The wireless device 10 includes a communication unit 40, a monitoring unit 42, a data processing unit 44, a control unit 46, and a selection unit 48.

[0021] (Communication Unit) The communication unit 40 performs the transmission and reception of packet signals on one of the multiple frequency channels. Specifically, the communication unit 40 receives packet signals in wireless communication by performing processing corresponding to wireless communication 20 and higher-level communication 24 as part of the reception process. The communication unit 40 enters a reception state, for example, according to the monitoring results of the monitoring unit 42 described later, and performs the reception of packet signals on the communication frequency channel. Here, as shown in Figure 3, the time T' required for the communication unit 40 to receive the packet signal is longer than the period T from the end of the monitoring period of the communication frequency channel to the start of the monitoring period of the next communication frequency channel (T'>>T). The communication unit 40 has an amplification function and a frequency conversion function, which generate a baseband signal. The communication unit 40 outputs the baseband signal to the data processing unit 44.

[0022] The communication unit 40 receives a baseband signal from the data processing unit 44 as part of the transmission process. The communication unit 40 has a frequency conversion function and an amplification function, which it uses to generate a packet signal. The communication unit 40 transmits the packet signal in wireless communication by executing processing corresponding to wireless communication 20 and higher-level communication 24, respectively. If the communication unit 40 is not sending or receiving a packet signal, it performs signal reception in order to execute the monitoring function in the monitoring unit 42. The communication unit 40 also performs reception processing on the received signal and outputs the result to the monitoring unit 42. Here, the communication unit 40 sets the frequency channel according to instructions from the control unit 46.

[0023] (Data volume) The data processing unit 44 receives a baseband signal from the communication unit 40 as part of its reception processing. The data processing unit 44 outputs the result of the reception processing. As part of its transmission processing, the data processing unit 44 generates a baseband signal when data to be transmitted is generated and outputs the generated baseband signal to the communication unit 40.

[0024] The data processing unit 44 outputs to the control unit 46 either when the packet signal was successfully received or when there was a problem with wireless communication using the communication frequency channel and the packet signal could not be successfully received. The control unit 46 stores the packet signal reception result received from the data processing unit 44.

[0025] (Monitoring Department) The monitoring unit 42 receives signals from the communication unit 40 and monitors the communication frequency channel that is waiting for packet signals. Monitoring the communication frequency channel is a process of measuring the power of the input signal, that is, received power measurement. This can also be called a radio wave presence / absence confirmation process. Here, the communication frequency channel to be measured for received power measurement and the timing to perform the received power measurement are instructed by the control unit 46. The received power measurement in the monitoring unit 42 will be explained in detail below. The monitoring unit 42 intermittently performs received power measurement before receiving packet signals and outputs the received power, which is the result of the received power measurement, to the control unit 46. For example, RSSI (Received Signal Strength Indicator) is used as the received power. If the received power received from the monitoring unit 42 is greater than a threshold, the control unit 46 instructs the communication unit 40 to receive packet signals from the communication partner.

[0026] Furthermore, the monitoring unit 42 intermittently monitors the radio wave conditions of backup frequency channels that are candidates for switching to the communication frequency channel. The monitoring unit 42 is instructed by the control unit 46 on the timing of monitoring the radio wave conditions (received power measurement) of the backup frequency channels. The control unit 46 instructs the monitoring unit 42 to perform the received power measurement of the backup frequency channels when the received power measurement of the communication frequency channel is not being performed, thereby monitoring the radio wave conditions of multiple frequency channels so that the monitoring periods of the communication frequency channel and the backup frequency channel do not overlap. In other words, the monitoring unit 42 monitors the backup frequency channels during the period T from the end of the monitoring period TA of the communication frequency channel to the start of the monitoring period TA of the next communication frequency channel. This allows the monitoring unit 42 to check the radio wave conditions of the frequency channels in advance, making it possible to immediately determine whether to switch from the communication frequency channel to the backup frequency channel when the communication condition on the communication frequency channel is poor, thereby preventing interruptions to the operation of the communication system 100. For example, the radio wave conditions of the communication frequency channel and one backup frequency channel are monitored alternately. This makes it possible to understand the radio wave conditions of the backup frequency channels, further reducing the need to interrupt the operation of the communication system 100.

[0027] Furthermore, the monitoring unit 42 is configured such that the period T from the end of the monitoring period for one communication frequency channel to the start of the monitoring period for the next communication frequency channel is shorter than the preamble length of the packet signal for the communication frequency channel transmitted from an external transmitter. This suppresses the loss of packet signals when they arrive on the communication frequency channel, enabling a highly reliable communication system.

[0028] (Selection section) The selection unit 48 selects the frequency channel that the communication unit 40 should use, that is, the frequency channel to be used for wireless communication 20, based on the results monitored by the monitoring unit 42. This allows the system to immediately switch to a backup frequency channel whose radio wave conditions are known in advance, even if the received power of the communication frequency channel is greater than the threshold, if the percentage of packets that are successfully received is less than the threshold. This prevents interruptions to the operation of the communication system and enables a highly reliable communication system. The selection unit 48 may also be configured to store the radio wave conditions of multiple backup frequency channels and select the one with the best radio wave conditions among the stored backup frequency channels. Furthermore, the selection unit 48 may be configured to switch automatically by the control unit 46, or the frequency channel may be switched manually.

[0029] (Operation of wireless device) The operation of the wireless device 10 will be explained using Figures 3 and 4. Figure 3 is a diagram showing the frequency channel monitoring procedure and the reception of packet signals on the frequency channel of the wireless device 10. Figure 4 is a flowchart showing the frequency channel monitoring procedure and selection procedure of the wireless device 10. The monitoring unit 42 intermittently measures the RSSI of the communication frequency channel before communication. In addition, the monitoring unit 42 measures the RSSI of the backup frequency channel while it is not measuring the RSSI of the communication frequency channel. For the purpose of explanation, the operation of the wireless device 10 will be explained in detail using Figure 4, with an example of the case where the RSSI of the communication frequency channel and one backup frequency channel are measured alternately, as shown in Figure 3.

[0030] First, the control unit 46 instructs the monitoring unit 42 to perform a measurement of the RSSI of the communication frequency channel. Upon receiving the instruction from the control unit 46, the monitoring unit 42 performs the measurement of the RSSI of the communication frequency channel and outputs the measurement result to the control unit 46 (S10).

[0031] The control unit 46 determines whether the measurement result of the RSSI of the communication frequency channel is above or below a threshold (S12).

[0032] If the measurement result of the RSSI of the communication frequency channel is below the threshold (N in S12), the control unit 46 instructs the communication unit 40 to switch from the communication frequency channel to the backup frequency channel so that the RSSI of the backup frequency channel can be measured. Next, the control unit 46 instructs the monitoring unit 42 to perform the RSSI measurement of the backup frequency channel. The monitoring unit 42 measures the RSSI of the backup frequency channel T1 seconds after the end of the measurement of the communication frequency channel and outputs the measurement result to the control unit 46 (S14). The control unit 46 stores the RSSI measurement result of the backup frequency channel received from the monitoring unit 42 (S16). Next, the control unit 46 instructs the communication unit 40 to switch from the backup frequency channel to the communication frequency channel. Next, the control unit 46 instructs the monitoring unit 42 to perform the RSSI measurement of the communication frequency channel. The monitoring unit 42 measures the RSSI of the communication frequency channel T2 seconds after the end of the measurement of the backup frequency channel.

[0033] Next, if the measurement result of the RSSI of the communication frequency channel is above the threshold (Y in S12), the control unit 46 instructs the communication unit 40 to perform packet signal reception on the communication frequency channel (S20). The data processing unit 44 determines, as part of the reception process, whether the packet signal was successfully received or whether there was a problem with the wireless communication using the communication frequency channel and the packet signal could not be received successfully (S22), and outputs this to the control unit 46. The control unit 46 stores the number of times the packet signal received from the data processing unit 44 was successfully received and the number of times the packet signal could not be received due to a problem with the wireless communication using the communication frequency channel (S (Success): number of times the packet signal was successfully received, F (False): number of times the packet signal could not be received due to an abnormality). If the frequency of successful packet signal reception satisfies the first predetermined condition (S / (S+F)>A (threshold): the proportion of successfully received packet signals out of the total number of received packet signals is above the threshold) (Y in S24), the control unit 46 returns to measuring the RSSI of the communication frequency channel (S10).

[0034] Further, when the frequency at which the packet signal can be normally received does not satisfy the first predetermined condition (N in S24), the control unit 46 determines that there is a problem with the wireless communication using the communication frequency channel, and determines whether the packet signal can be normally received if it is a spare frequency channel. Therefore, it is determined whether the second predetermined condition (B < C (threshold): the average value (B) of the RSSI measurement results of the spare frequency channel for the most recent n times is less than the threshold) is satisfied (S26, S28). When the monitoring result of the radio wave intensity of the spare frequency channel satisfies the second predetermined condition (Y in S28), the control unit 46 determines that the spare frequency channel is a frequency channel with a good communication state with less noise, and requests the communication unit 40 to switch from the communication frequency channel to the spare frequency channel. A switching request signal is transmitted from the communication frequency channel to the transmitter outside the communication partner (S29). Subsequently, the setting is changed so that the spare frequency channel can execute the reception of the packet signal as the communication frequency channel, and the frequency channel used in the communication frequency channel is changed to the spare frequency channel. The setting is changed (S30). Further, when the monitoring result of the radio wave intensity of the spare frequency channel does not satisfy the second predetermined condition (N in S28), the control unit 46 returns to the measurement of the RSSI of the communication frequency channel (S10).

[0035] So far, the movement in the case where there is one spare frequency channel during the period T from the end of the monitoring period of the communication frequency channel to the start of the monitoring period of the next communication frequency channel has been described. In the following, the operation of the wireless device 10 in the case where there are N spare frequency channels during the period T from the end of the monitoring period of the communication frequency channel to the start of the monitoring period of the next communication frequency channel will also be described.

[0036] The control unit 46 instructs the monitoring unit 42 to execute the measurement of the RSSI of the communication frequency channel. The monitoring unit 42 that has received the instruction from the control unit 46 executes the measurement of the RSSI of the communication frequency channel and outputs the measurement result to the control unit 46 (S10). The control unit 46 determines whether the measurement result of the RSSI of the communication frequency channel is greater than or equal to the threshold value or less than the threshold value (S12).

[0037] If the RSSI measurement result of the communication frequency channel is below the threshold, the control unit 46 instructs the communication unit 40 to switch from the communication frequency channel to the first backup frequency channel so that the RSSI of the first backup frequency channel can be measured. Subsequently, the control unit 46 instructs the monitoring unit 42 to perform the RSSI measurement of the first backup frequency channel. T1 seconds after the end of the measurement of the communication frequency channel, the monitoring unit 42 measures the RSSI of the first backup frequency channel and outputs the measurement result to the control unit 46. The control unit 46 stores the measurement result of the RSSI of the first backup frequency channel received from the monitoring unit 42 (S14, S16).

[0038] Next, the control unit 46 instructs the communication unit 40 to switch from the first backup frequency channel to the second backup frequency channel. The control unit 46 instructs the monitoring unit 42 to measure the RSSI of the second backup frequency channel. The monitoring unit 42 measures the RSSI of the second backup frequency channel and outputs the measurement result to the control unit 46. The control unit 46 stores the measurement result of the RSSI of the second backup frequency channel received from the monitoring unit 42 (S14, S16).

[0039] Next, the control unit 46 instructs the communication unit 40 to switch from the second backup frequency channel to the third backup frequency channel. Then, the control unit 46 instructs the monitoring unit 42 to measure the RSSI of the third backup frequency channel. The monitoring unit 42 measures the RSSI of the third frequency channel and outputs the measurement result to the control unit 46. The control unit 46 stores the measurement result of the RSSI of the third backup frequency channel received from the monitoring unit 42 (S14, S16).

[0040] In this manner, the control unit 46 instructs the communication unit 40 to switch from the (N-1)th backup frequency channel to the Nth backup frequency channel. Subsequently, the control unit 46 instructs the monitoring unit 42 to measure the RSSI of the Nth backup frequency channel and outputs the measurement result to the control unit 46. The control unit 46 stores the measurement result of the RSSI of the Nth backup frequency channel received from the monitoring unit 42 (S14, S16).

[0041] Next, the control unit 46 instructs the communication unit 40 to switch from the Nth backup frequency channel to the communication frequency channel. Then, the control unit 46 instructs the monitoring unit 42 to measure the RSSI of the communication frequency channel. The monitoring unit 42 measures the RSSI of the communication frequency channel T2 seconds after the end of the measurement of the Nth backup frequency channel (S10).

[0042] If, among the N spare frequency channels, there is a spare frequency channel that does not meet the second predetermined condition, the control unit 46 may determine that the spare frequency channel that does not meet the second predetermined condition is a noisy frequency channel with poor communication conditions, and may reduce the frequency of monitoring of the frequency channel determined to be a frequency channel with poor communication conditions by imposing a penalty period of a certain period (for example, one day), and increase the frequency of monitoring of the frequency channels with good communication conditions.

[0043] (Appearance) The wireless device (10) according to the first embodiment comprises a monitoring unit (42) and a communication unit (40). The monitoring unit (42) intermittently monitors the radio wave conditions of the communication frequency channel. The communication unit (40) enters a receiving state according to the monitoring results of the monitoring unit (42) and performs the reception of packet signals of the communication frequency channel. The monitoring unit (42) monitors the radio wave conditions of backup frequency channels that are candidates for replacement so as not to overlap with the monitoring period of the communication frequency channel.

[0044] According to the wireless device (10) described above, by checking the communication status of the backup frequency channel in advance, it is possible to quickly switch to the backup frequency channel when the communication status of the communication frequency channel is poor, thereby suppressing interruptions to the operation of the communication system (100) and improving the reliability of communication.

[0045] In the wireless device (10) according to the second embodiment, the monitoring unit (42) alternately monitors the radio wave conditions of the communication frequency channel and the backup frequency channel, as in the first embodiment.

[0046] According to the wireless device (10) described above, it is possible to grasp the radio wave conditions of the immediately preceding backup frequency channel, thereby improving the reliability of communication.

[0047] In the wireless device (10) according to the third embodiment, in the first or second embodiment, the monitoring unit (42) is set such that the period from the end of the monitoring period for one communication frequency channel to the start of the monitoring period for the next communication frequency channel is shorter than the preamble length of the packet signal of the communication frequency channel transmitted from an external transmitter.

[0048] According to the wireless device (10) described above, it is possible to suppress the loss of packet signals when a packet signal arrives on the communication frequency channel, thereby improving the reliability of communication.

[0049] In the wireless device (10) according to the fourth embodiment, a control unit (46) is further provided that controls the switching of frequency channels based on the monitoring results of the monitoring unit (42) in any embodiment of the first to third embodiments. When the frequency at which packet signals on the communication frequency channel are received normally does not satisfy the first predetermined condition, and the monitoring result of the monitoring unit (42) monitoring the radio wave strength of the backup frequency channel satisfies the second predetermined condition, the control unit (46) causes the communication unit (40) to transmit a request signal to switch to the backup frequency channel on the communication frequency channel, changes the frequency channel of the backup frequency channel as the communication frequency channel, and changes the frequency channel that was used as the communication frequency channel to be set as the backup frequency channel.

[0050] According to the wireless device (10) in the above embodiment, it is possible to switch to a frequency channel suitable for the surrounding environment without interrupting the operation of the communication system (100), thereby improving the reliability of communication.

[0051] The wireless communication method according to the fifth embodiment includes a monitoring step and a communication step. The monitoring step intermittently monitors the radio wave conditions of the communication frequency channel. The communication step enters a receiving state according to the monitoring results in the monitoring step and performs the reception of packet signals on the communication frequency channel. The monitoring step monitors the radio wave conditions of a backup frequency channel that is a candidate for replacement, so as not to overlap with the monitoring period of the communication frequency channel.

[0052] According to the wireless communication method described above, by checking the communication status of the backup frequency channel in advance, it is possible to quickly switch to the backup frequency channel when the communication status of the communication frequency channel is poor, thereby suppressing interruptions to the operation of the communication system (100) and improving the reliability of communication.

[0053] The program according to the sixth embodiment causes a computer system to execute a wireless communication method.

[0054] According to the program described above, a program can be provided to cause a computer system to execute a wireless communication method. [Explanation of symbols]

[0055] 10 Radio equipment 40 Communications Department 42 Monitoring Department 46 Control Unit 100 Communication Systems

Claims

1. A wireless device comprising: a monitoring unit that intermittently monitors the radio wave conditions of a communication frequency channel; and a communication unit that enters a receiving state according to the monitoring results of the monitoring unit and performs the reception of packet signals on the communication frequency channel, The monitoring unit monitors the radio wave conditions of alternative frequency channels that are candidates for replacement, so as not to overlap with the monitoring period of the communication frequency channel. Radio equipment.

2. The monitoring unit alternately monitors the radio wave conditions of the communication frequency channel and the backup frequency channel. The wireless device according to claim 1.

3. The monitoring unit is configured such that the period from the end of the monitoring period for the communication frequency channel to the start of the monitoring period for the next communication frequency channel is shorter than the preamble length of the packet signal of the communication frequency channel transmitted from the external transmitter. The wireless device according to claim 1.

4. The system further includes a control unit that controls the switching of frequency channels based on the monitoring results of the aforementioned monitoring unit. When the frequency at which the packet signal of the communication frequency channel is received normally does not satisfy the first predetermined condition, and the monitoring result of the radio wave intensity of the backup frequency channel by the monitoring unit satisfies the second predetermined condition, The control unit causes the communication unit to transmit a request signal to switch to the backup frequency channel on the communication frequency channel, changes the frequency channel of the backup frequency channel as the communication frequency channel, and changes the frequency channel that was being used as the communication frequency channel to be set as the backup frequency channel. A wireless device according to any one of claims 1 to 3.

5. The system comprises a monitoring step of intermittently monitoring the radio wave conditions of a communication frequency channel, and a communication step of entering a receiving state according to the monitoring results in the monitoring step and performing the reception of packet signals on the communication frequency channel. The aforementioned monitoring step monitors the radio wave conditions of the alternative frequency channel, which is a candidate for replacement, so as not to overlap with the monitoring period of the communication frequency channel. Wireless communication method.

6. The computer system is made to execute the wireless communication method described in claim 5. program.

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