JPH11177531A - Low speed frequency hopping spread spectrum communication method and radio communication system using the communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of communication efficiency for an entire radio communication system by changing a hopping pattern into a communication fault countermeasure hopping pattern using the frequency of a band other than the frequency that is used for the communication fault countermeasure hopping pattern and accordingly lowering the frequency collision probability. SOLUTION: If a certain radio salve station 12 included in a radio zone Z1 detects a disturbance radio wave sent from a high frequency generator via a disturbance radio wave detection means and cannot perform the radio communication with a radio master station 11, the station 11 notifies by wire a communication management server 40 of the above fact. The serve 40 selects a 1st communication fault countermeasure hopping pattern of the channel data for the relevant station 11 having a communication fault of the zone Z1 and notifies the station 11 of the switching of patterns via a pattern switching means. Meanwhile, the server 40 selects a 2nd communication fault countermeasure hopping pattern of the channel data for a radio master station 21 of a radio zone Z2 that is adjacent to the zone Z1 and notifies the station 21 of the switching of patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low frequency hopping spread spectrum communication method and a radio communication system using this communication method.

[0002]

2. Description of the Related Art One wireless master station and one or more wireless slave stations form a wireless zone, and the wireless master station and the wireless slave stations communicate with each other in this wireless zone. Is a low frequency hopping spread spectrum communication method in which all the stations perform communication while switching the use frequency according to a common hopping pattern. This low-speed frequency hopping spread spectrum communication method is a method in which a carrier frequency operates at a switching speed lower than the bit speed of an information signal, and a plurality of bits are transmitted by one carrier. As a wireless access method, CSMA / CA (Carrier Sense Multip
le Access / Collision Avoidance). According to the CSMA / CA method, when a wireless slave station intends to transmit to a wireless master station, it is checked whether there is another wireless slave station transmitting in the same zone. If it waits for a random time, it is checked again. Generally, when an error occurs, retransmission is performed.

Conventionally, in a radio communication system adopting such a low-speed frequency hopping spread spectrum communication method, a system administrator selects an appropriate pattern from several types of hopping patterns prepared in advance and selects an appropriate pattern within the same radio zone. Set to each station. In this case, when there are a plurality of wireless zones, a different hopping pattern is set for each zone so that use frequencies do not collide as much as possible in adjacent wireless zones. Then, after operating the system for a certain period, a log such as the communication history of each station is acquired, and the log is analyzed to recognize the communication quality. When the quality is poor, the communication quality is improved by resetting to another hopping pattern.

[0004] The frequency band used in low-speed frequency hopping spread spectrum communication is usually 2.471.
GHz (gigahertz) to 2.497 GHz,
A radio wave generated from a high-frequency generator such as a microwave oven is one that can be an interfering radio wave in this frequency band. FIG. 8 shows the relationship between the noise level (vertical axis) and the frequency (horizontal axis) by the high frequency generator. As shown in the figure, the high-frequency generation device uses a frequency band (2.471 GHz to 2.497 G) used in low-speed frequency hopping spread spectrum communication.
Hz), the lower half band (lower band: 2.4)
(71 GHz to 2.484 GHz).

For this reason, in an environment in which a high frequency generator such as a microwave oven is installed, such as a supermarket or a convenience store, a wireless POS (PoPo) using a low-speed frequency hopping spread spectrum communication system is used.
When an int Of Sales (point-of-sale information management) system is constructed, the upper half band (higher band:
By selecting a pattern using only the frequency of 2.484 GHz to 2.497 GHz), good communication quality can be obtained.

[0006]

However, when there are a plurality of radio zones, an interference wave from the high frequency generator is detected in any one of the zones, and the hopping pattern in that zone is detected. Upper half band where the influence of radio waves is small (upper band: 2.48
When the pattern is changed to a pattern using only the frequency of 4 GHz to 2.497 GHz), the hopping pattern of the other wireless zone remains unchanged, and the frequency collision probability with the adjacent wireless zone is increased. For this reason, CSM
There is a problem that the number of wireless stations waiting for transmission by the A / CA method increases, and the communication efficiency of the entire system decreases.

Therefore, according to the present invention, when performing low-speed frequency hopping spread spectrum communication in a plurality of radio zones, it is possible to detect jamming radio waves in any one of the zones and to avoid the hopping pattern used in that zone. It is an object of the present invention to provide a low-speed frequency hopping spread spectrum communication method capable of preventing a reduction in communication efficiency of the entire system even if the hopping pattern is changed to a hopping pattern using only frequencies in a frequency band, and a wireless communication system using this communication method. Things.

[0008]

According to the first aspect of the present invention, a plurality of wireless zones are formed by one wireless master station and one or more wireless slave stations, respectively. When a station and a wireless slave station perform low-frequency hopping spread spectrum communication in accordance with a predetermined hopping pattern, when a jamming radio wave for low-speed frequency hopping spread spectrum communication is detected in any one of the radio zones, The hopping pattern used by the radio base station and the radio slave stations in the zone is changed to the first communication failure countermeasure hopping pattern using only frequencies in a frequency band capable of avoiding jamming radio waves. The hopping pattern used by the wireless master station and wireless slave station in another wireless zone is used as the first communication failure countermeasure hopping pattern. That is a slow frequency hopping spread spectrum communication method to be changed to the second communication failure countermeasure hopping pattern using frequency bands other than the frequency band of frequencies.

According to a second aspect of the present invention, a plurality of wireless zones are formed by one wireless master station and one or more wireless slave stations, respectively, and the wireless master station of each wireless zone is formed by a host device. In a wireless communication system in which a wireless master station and a wireless slave station perform low-speed frequency hopping spread spectrum communication according to a hopping pattern assigned by the host device in each wireless zone, the host device includes:
When detecting jamming radio waves for low-speed frequency hopping spread spectrum communication in any one of the radio zones, the hopping pattern used by the radio base station and the radio slave station in the radio zone is changed to only frequencies in a frequency band that can avoid the jamming radio waves. The first communication failure countermeasure hopping pattern is changed to the first communication failure countermeasure hopping pattern used, and the hopping pattern used by the wireless master station and the wireless slave station in another wireless zone adjacent to the wireless zone is used. And means for changing to a second hopping pattern for communication failure countermeasures using a frequency of a frequency band other than the frequency band of the frequency used in the above.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram in which one wireless master station 11 and a plurality of wireless slave stations 12 (12-1, 12-
2,... 12-n) to form a first wireless zone Z1.
Wireless master stations 21 and a plurality of wireless slave stations 22 (22-1, 2
2-2,... 22-n) to form a second wireless zone Z2,
One wireless master station 31 and a plurality of wireless slave stations 32 (32-1,
32-2) form a third wireless zone Z3. Note that the first wireless zone Z1 and the second wireless zone Z2, and the second wireless zone Z2 and the third wireless zone Z
3 are adjacent to each other, and the first wireless zone Z1 and the third wireless zone Z3 are not adjacent to each other.

A communication management server 40 functioning as a host device is provided. Each of the wireless zones Z1, Z2, Z3 is connected to the communication management server 40 via a communication cable 50.
Wireless master stations 11, 21 and 31 are connected by wire. The communication management server 40 communicates with the wireless master stations 11, 21, 31 and the wireless slave stations 1 in each of the wireless zones Z1, Z2, Z3.
2, 22, 32 perform wireless communication by the low-speed frequency hopping spread spectrum communication method.
It has a function of setting a hopping pattern unique to each of the radio base stations 11, 21, and 31 and each of the radio substations 12, 22, and 32 for each of Z1, Z2, and Z3. The CSMA / CA method is adopted as a wireless access method.

As shown in FIG. 3, the radio master stations 11, 21, 31 and the radio slave stations 12, 22, 32 transmit radio waves from an antenna 61 or receive radio waves via the antenna 61. The circuit unit 62 is connected to a wired external device (in the case of the wireless master stations 11, 21 and 31, the communication management server 4
0, in the case of the wireless slave stations 12, 22, 32, for example, a data processing terminal), an interface unit 63 for controlling communication with the wireless circuit unit 62, a control unit 64 for controlling the wireless circuit unit 62 and the interface unit 63, and a memory unit 65. ing.

The control section 64 has timer means, counter means, various arithmetic means, and the like. Further, it also has a jamming wave detecting means 64a for automatically detecting jamming waves generated from a high frequency generator such as a microwave oven. In addition,
Since the interfering radio waves generated from a high frequency generator such as a microwave oven have a characteristic that the pulse width is extremely shorter than the radio waves generated by ordinary data communication,
In step 4a, it is sufficient to detect the interference radio wave from the high-frequency generator by distinguishing it from the radio wave by normal data communication using this characteristic.

The memory section 65 has a hopping pattern memory 65a for storing sequence data indicating various hopping patterns, and a current pattern memory 65b for storing channel data for specifying a hopping pattern currently used.

Incidentally, in this embodiment, for example, 2.
23 types of hopping frequencies f1 to f23 selected from within the frequency band of 471 GHz to 2.497 GHz are represented by f
It is set at 1 MHz intervals from 1 = 2.473 GHz to f23 = 2.495 GHz. 4 (a),
As shown in (b) and (c), three types of normal hopping patterns ch1, ch2, and ch3 formed by randomly arranging the 23 types of hopping frequencies f1 to f23.
As shown in FIGS. 8 (d) and 8 (e), a band higher than the frequency band f12 = 2.484 GHz in which the influence of the interfering radio wave from the high frequency generator such as a microwave oven is reduced (FIG. 8).
(See (f), (f) and (c) of FIG. 2), two types of first communication failure countermeasure hopping patterns ch11 and ch12 formed by randomly arranging 11 types of hopping frequencies f13 to f23.
As shown in (g), two types of second communication failure countermeasures formed by randomly arranging eleven types of hopping frequencies f1 to f11 not used in the first communication failure countermeasure hopping patterns ch11 and ch12. Hopping pattern c
Each sequence data of h21 and ch22 is transferred to each wireless zone Z.
The hopping pattern memories 65a of the wireless master stations 11, 21, 31 and the wireless slave stations 12, 22, 32 in 1, Z2, and Z3 are stored in advance.

As shown in FIG. 3, the communication management server 40 includes an interface unit 71 for controlling communication with each of the radio base stations 11, 21, and 31 connected via the communication cable 50, a keyboard, a display, and the like. I / O section 72 to which the input / output devices are connected, the interface section 71
Control section 73 for controlling I / O section 72 and memory section 7
4.

The control section 73 has timer means, counter means, various arithmetic means, and the like. When a communication failure caused by a radio wave from the high-frequency generator is detected in any of the wireless zones Z1, Z2, and Z3, the hopping pattern used in each of the wireless zones Z1, Z2, and Z3 is changed to a normal hopping pattern. There is provided a pattern switching means 73a for switching from ch1, ch2, ch3 to a hopping pattern for communication failure countermeasures ch11, ch12 or ch21, ch22.

As shown in FIG. 5, the memory section 74 has a pattern memory for each zone for storing channel data of a hopping pattern currently used by each wireless station in each wireless zone Z1, Z2, Z3. 74a and a switching pattern management table 74b. The switching pattern management table 74b is a table referred to by the pattern switching unit 73a. When a communication failure occurs in each of the wireless zones Z1, Z2, and Z3, the switching pattern management table 74b stores information in each of the wireless zones Z1, Z2, and Z3. Channel data of a communication failure countermeasure hopping pattern used by each wireless station is set in advance, and when one of two adjacent wireless zones uses the first communication failure countermeasure hopping pattern, the other uses the second communication zone. The channel data is set so as to use the hopping pattern for troubleshooting.

Here, the pattern switching means 73a will be specifically described with reference to the flowchart of FIG. That is, when the control unit 73 of the communication management server 40 detects a wireless zone in which a communication failure has occurred due to an interfering radio wave from the high-frequency generator (YES in ST1), the control unit 73 refers to the switching pattern management table 74b, and The channel data of the switching pattern set corresponding to the wireless zone in which the communication failure has occurred is read (ST2). First, of the channel data of the switching pattern, the channel data of the wireless zone in which the communication failure has occurred is acquired, and the channel data is stored in the current pattern memory 74a for each zone.
Is set to overwrite the area of the corresponding wireless zone and transmitted to the wireless master station of the corresponding wireless zone via the interface unit 71 (ST3). Next, from among the channel data of the same switching pattern, channel data of wireless zones other than the wireless zone in which the communication failure has occurred are acquired, and these channel data are stored in the corresponding wireless zone in the zone-based current pattern memory 74a. Each area is overwritten and the interface unit 71
To the wireless master station of the corresponding wireless zone in sequence (S
T4).

The pattern switching means 73a having such a configuration
Is executed by the control unit 73 of the communication management server 40, the wireless master stations 11, 21, 31 rewrite the contents of the current pattern memory 65b to the channel data received from the communication management server 40, and Is wirelessly transmitted to each of the wireless slave stations 12, 22, and 32 in the same zone. Each of the wireless slave stations 12, 22, and 32 stores the contents of the current pattern memory 65b in the wireless master stations 11, 21, and 21 in the same zone.
Rewrite to the channel data received from 31. As a result, in each of the wireless zones Z1, Z2, and Z3, thereafter, wireless communication is performed according to the hopping pattern of the rewritten channel data.

In the wireless communication system of the present embodiment configured as described above, the normal hopping pattern of the channel data ch1 is now set for the wireless master station 11 and each wireless slave station 12 forming the wireless zone Z1. The normal hopping pattern of the channel data ch2 is set for the wireless master station 21 and each wireless slave station 22 forming the wireless zone Z2, and for the wireless master station 31 and each wireless slave station 32 forming the wireless zone Z3. It is assumed that the normal hopping pattern of the channel data ch3 has been set. At this time,
Zone-based current pattern memory 74 of the communication management server 40
As shown in FIG. 5, a stores channel data ch1 corresponding to the wireless zone Z1 and channel data ch2 corresponding to the wireless zone Z2.
3, channel data ch3 is stored. The channel data ch1 is stored in the current pattern memory 65b of the wireless master station 11 and each wireless slave station 12 forming the wireless zone Z1, and the current pattern memory 65b of the wireless master station 21 and each wireless slave station 22 forming the wireless zone Z2 is stored. Pattern memory 65b
Stores channel data ch2 in the wireless zone Z3.
The channel data ch3 is stored in the current pattern memory 65b of the wireless master station 31 and each wireless slave station 32 which form. Thereby, the wireless master station 1 forming the wireless zone Z1
1 and each wireless slave station 12, wireless communication is performed in the normal hopping pattern ch1 shown in FIG.
Further, between the wireless master station 21 forming the wireless zone Z2 and each wireless slave station 22, wireless communication is performed in the normal hopping pattern ch2 shown in FIG. 4B. Further, the wireless master station 31 and each wireless slave station 32 forming the wireless zone Z3
The wireless communication is performed with the normal hopping pattern ch3 shown in FIG.

In such a state, for example, a certain wireless slave station 12 in the wireless zone Z1 receives the jamming wave detecting means 64a.
When radio interference with the radio base station 11 cannot be performed by detecting an interfering radio wave from a high frequency generator such as a microwave oven due to the action of the radio base station 11, the radio base station 11
To that effect. Then, the communication management server 40
In the above, the operation of the pattern switching means 73a selects the first communication failure countermeasure hopping pattern of the channel data ch11 and notifies the wireless master station 11 in the wireless zone Z1 in which the communication failure has occurred of the switching. In addition, the wireless master station 21 in the wireless zone Z2 adjacent to the wireless zone Z1.
, A second communication failure countermeasure hopping pattern of the channel data ch21 is selected and the switching is notified. Further, the wireless zone Z2 is not adjacent to the wireless zone Z1 but is adjacent to the wireless zone Z1.
With respect to the wireless master station 31 in the adjacent wireless zone Z3, the first communication failure countermeasure hopping pattern of the channel data ch12 is selected and the switching is notified.

As a result, thereafter, between the wireless master station 11 and the wireless slave stations 12 forming the wireless zone Z1, FIG.
Wireless communication is performed using the first communication failure countermeasure hopping pattern ch11 shown in FIG. In addition, between the wireless master station 21 forming the wireless zone Z2 and each wireless slave station 22, wireless communication is performed using the second communication failure countermeasure hopping pattern ch21 illustrated in FIG. Further, the wireless zone Z
The wireless communication is performed between the wireless master station 31 forming the wireless communication station 3 and each wireless slave station 32 by the first communication failure countermeasure hopping pattern ch12 shown in FIG.

Therefore, in the radio zone Z1 in which a communication failure has occurred due to the interfering radio waves from the high-frequency generator, the first hopping pattern ch1 immediately uses only the frequency at which the influence of the interfering radio waves from the high-frequency generator is small. Hopping pattern ch for communication failure countermeasures
Switching to 11 prevents communication failure and improves communication quality.

In the wireless zone Z2 adjacent to the wireless zone Z1, the second communication failure countermeasure hopping pattern ch21 using only the frequency not used in the first communication failure countermeasure hopping pattern ch11 is automatically transmitted. Is switched to the wireless zone Z1 and the wireless zone Z2.
There is no collision in use frequency between the two. Further, in the wireless zone Z3 adjacent to the wireless zone Z2 using the second communication failure countermeasure hopping pattern ch21, the second communication failure countermeasure hopping pattern c is also used.
Since the switching to the first hopping pattern for communication failure countermeasure ch12 using only the frequency not used in h21 is automatically performed, the used frequency does not collide between the wireless zone Z2 and the wireless zone Z3. Therefore, the frequencies used do not collide between adjacent wireless zones, and the communication efficiency of the entire system is improved.

This means that a communication failure occurs in the radio zone Z2 due to a jamming radio wave from the high-frequency generator, and a communication fault occurs in the radio zone Z3 due to the jamming radio wave from the high-frequency generator. The same applies to the case.

That is, when a communication failure occurs due to an interfering radio wave from the high-frequency generator in the wireless zone Z2, the normal hopping pattern ch2 is changed to the first communication failure countermeasure hopping pattern ch11 in the wireless zone Z2. , The communication failure is avoided. In the wireless zone Z1 and the wireless zone Z3 adjacent to the wireless zone Z2, the second communication failure countermeasure hopping patterns ch21 and ch22 using only the frequencies not used in the first communication failure countermeasure hopping pattern ch11. Automatically between the wireless zone Z2 and the wireless zone Z1 and the wireless zone Z
The use frequency does not collide between the wireless zone Z3 and the wireless zone Z3.

Similarly, when a communication failure occurs due to the interfering radio wave from the high frequency generator in the radio zone Z3,
In the wireless zone Z3, the normal hopping pattern ch3 is automatically switched to the first communication failure countermeasure hopping pattern ch11, so that a communication failure is avoided. A wireless zone Z adjacent to the wireless zone Z3
2 automatically switches to the second communication failure countermeasure hopping pattern ch22 using only the frequency not used in the first communication failure countermeasure hopping pattern ch11, and is connected to the wireless zone Z1 adjacent to the wireless zone Z2.
In the above, the switching to the first communication failure countermeasure hopping pattern ch12 that uses only the frequency not used in the second communication failure countermeasure hopping pattern ch22 is automatically performed. There is no.

As described above, according to the present embodiment, the plurality of wireless zones Z1, Z2, and Z3 are respectively connected to one wireless master station 11, 21, 31, and one or more wireless slave stations 12, 22, 3, and 3.
2 and wireless master stations 11, 21, 31 and wireless slave stations 12, 22, 32 perform low-speed hopping spread spectrum communication in each wireless zone Z1, Z2, Z3 according to a predetermined hopping pattern. In this case, when a jamming radio wave for the low frequency hopping spread spectrum communication is detected in any one of the radio zones, first, the hopping pattern used by the radio base station and the radio slave station in the radio zone is changed to a frequency that can avoid the jamming radio wave. Change to the first hopping pattern for communication failure countermeasures ch11 and ch12 using only the frequency of the band, and then use the hopping pattern used by the wireless master station and wireless slave station in another wireless zone adjacent to the wireless zone. Of the frequency band other than the frequency band of the frequency used in the first hopping patterns for communication failure countermeasures ch11 and ch12. Is changed to the second communication failure countermeasure hopping patterns ch21 and ch22, which can not only reliably and promptly avoid a communication failure due to jamming radio waves, but also reduce the frequency collision probability between adjacent wireless zones. There is no danger of heightening. Therefore, the communication efficiency of the entire system can be improved, and the system can be stabilized.

In the above-described embodiment, each radio station detects the jamming wave radiated from the high-frequency generator such as the microwave oven by the jamming wave detecting means 64a, and notifies the communication management server 40 by wire to that effect. Then, the pattern switching means 73a was activated, but the system administrator confirmed that a communication failure due to the interfering radio wave from the high frequency generator occurred in any of the wireless zones, and the communication management server 40 The present invention also includes a case where the pattern switching means 73a is operated by inputting an operation to that effect through an input device provided in.

In the above-described embodiment, the communication failure countermeasure hopping pattern includes a first communication failure countermeasure hopping pattern using only frequencies in a frequency band capable of avoiding jamming radio waves, and the first communication failure countermeasure hopping pattern. And a second communication failure countermeasure hopping pattern using a frequency in a band other than the frequency band of the frequency used in the communication hopping pattern. When the two wireless zones adjacent to the wireless zone where a communication failure has occurred are adjacent to each other, a pattern using the upper-band frequency is set for one of the two patterns. Alternatively, a pattern using the lower band frequency may be set on the other side to further reduce the frequency collision probability.

[0032]

As described in detail above, according to the present invention,
When performing low-speed frequency hopping spread spectrum communication in each of a plurality of wireless zones, a jamming radio wave is detected in any one of the zones, and a hopping pattern used in that zone uses only frequencies in a frequency band capable of avoiding the jamming radio waves. Even if the hopping pattern is changed, the effect of preventing the communication efficiency of the entire system from being reduced can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main configuration of a wireless station included in the wireless communication system.

FIG. 3 is a block diagram showing a configuration of a main part of a communication management server configuring the wireless communication system;

FIG. 4 is an example diagram of a hopping pattern used in the embodiment.

FIG. 5 is a diagram showing an example of a current pattern memory for each zone shown in FIG. 3;

FIG. 6 is an example of a switching pattern management table shown in FIG. 3;

FIG. 7 is a flowchart used for explaining the pattern switching means shown in FIG. 3;

FIG. 8 is a diagram showing a relationship between a noise level and a frequency by the high frequency generator.

[Explanation of symbols]

 Z1, Z2, Z3 ... wireless zone 11, 21, 31 ... wireless master station 12, 22, 32 ... wireless slave station 40 ... communication management table 64a ... jamming wave detecting means 73a ... pattern switching means 74a ... zone-based current pattern memory 74b … Switching pattern management table

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H04Q 7/28

Claims (2)

[Claims] 1. A plurality of wireless zones each comprising one wireless master station and one or more wireless slave stations, wherein the wireless master station and the wireless slave stations are predetermined in each wireless zone. When performing low-speed frequency hopping spread spectrum communication in accordance with a hopping pattern, if a jamming radio wave for low-speed frequency hopping spread spectrum communication is detected in any one of the radio zones, first, the radio master station and the radio slave station in that radio zone are detected. Is changed to the first communication failure countermeasure hopping pattern using only a frequency band in a frequency band that can avoid the jamming radio wave, and then the hopping pattern in another wireless zone adjacent to the wireless zone is changed. The hopping pattern used by the master station and the wireless slave station is the frequency of the frequency used in the first communication failure countermeasure hopping pattern. Slow Frequency Hopping spread spectrum communication method is characterized in that so as to change to the second communication failure countermeasure hopping pattern using frequency bands other than the band. A plurality of wireless zones each formed by one wireless master station and one or more wireless slave stations, and a wireless master station in each wireless zone connected to a host device by wire; In a wireless communication system in which the wireless master station and the wireless slave station perform low-speed frequency hopping spread spectrum communication in accordance with a hopping pattern assigned by the host device, the host device has a low speed in any one wireless zone. When detecting the jamming radio wave for the frequency hopping spread spectrum communication, the hopping pattern used by the radio base station and the radio slave station in the radio zone is changed to the first communication obstacle using only the frequency of the frequency band capable of avoiding the jamming radio wave. Change to the hopping pattern for the countermeasure, and change the wireless master in another wireless zone adjacent to the wireless zone. And wherein the hopping pattern radio personal station uses first
A low frequency hopping spread spectrum communication method, characterized by comprising means for changing to a second communication failure countermeasure hopping pattern using a frequency other than the frequency band of the frequency used in the communication failure countermeasure hopping pattern. The wireless communication system used.