JP4844745B2 - Wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication system including a pair of wireless communication devices that perform wireless communication using an arbitrary frequency channel selected from a plurality of common frequency channels, and particularly using a specific low-power radio. The present invention relates to a radio communication system suitable for use in a radio communication system that performs security data communication.

  There is a low-power security wireless system in which security information detected by a gas leak sensor or the like is transmitted from a wireless slave unit to a wireless master unit by a specific low-power radio and transmitted from the wireless master unit to a center device via a public line (Patent Document 1). reference).

  By the way, the biggest obstacle in wireless communication is jamming radio waves, and if a jamming radio wave is present when the radio slave unit transmits radio waves, the radio master unit cannot normally receive security information from the radio slave unit. Therefore, as shown in FIG. 12, a plurality of frequency channels (here, 1 to 10 channels) to be used between the wireless slave device on the transmission side and the wireless parent device on the reception side are determined in advance, and the transmission side and the reception are performed. A wireless communication system in which the side can select the frequency channels in the same order (1, 2, 3,..., 10 channels) and perform transmission and reception to avoid the influence of jamming radio waves. Yes (see Patent Document 2).

  In such a wireless communication system, as shown in the column of “reception shift 0” in FIG. 12, if the timing for selecting the same frequency channel on the transmission side and the reception side coincide, The frequency channels of all the channels that are sequentially switched coincide with each other. However, as shown as “reception deviations 1 to 9” in FIG. 12, the timing at which the transmission side and the reception side select the same frequency channel does not match due to the time difference between the clocks on the transmission side and the reception side. If they are shifted, the frequency channels of each other will not be matched indefinitely. That is, in the case of FIG. 12, the frequency channel matches the 10 kinds of deviations 0 to 9 only when the deviation is 0, so the probability that the frequency channels match is only 10%. Absent.

  Therefore, although not described in the literature, as shown in FIG. 13, the frequency channel on the transmission side is switched to ascending order (channels 1, 2, 3,... 10), and the frequency channel on the reception side is arranged in descending order. There is a wireless communication system in which the frequency channel is matched when the amount of deviation is odd by switching to (channels 10, 9, 8,... 1), and the probability of matching is improved to 50%.

  However, the probability of 50% is insufficient for a system that transmits urgent and important information such as security information, and it is desirable to approach 100%.

JP-A-6-291723 JP-A-11-113045

  The present invention has been made in view of such problems, and an object thereof is a pair of wireless communication in which wireless communication is performed using arbitrary frequency channels selected from a plurality of common frequency channels. In a wireless communication system equipped with an apparatus, when a transmission side and a reception side switch frequency channels, the probability that the frequency channels match each other is improved.

The invention of claim 1 is a wireless communication system comprising a pair of wireless communication devices that perform wireless communication using an arbitrary frequency channel selected from a plurality of common frequency channels, wherein one wireless communication device is , Having a transmission channel switching means for switching the plurality of frequency channels in a predetermined order to be set in a transmission unit, and the other wireless communication device is configured to switch the transmission channel switching means with the number of skips of one or more. And receiving channel switching means for setting in the receiving unit by switching in the same order.
According to a second aspect of the present invention, in the wireless communication system according to the first aspect, the other wireless communication device has two receiving units having different set frequency channels.

(Function)
According to the first aspect of the present invention, one radio communication device switches a plurality of frequency channels in a predetermined order and sets the transmission unit, and the other radio communication device sets the plurality of frequency channels to one or more skip counts. Thus, the transmission channel switching means is switched in the same order and set in the receiving unit.
According to the invention of claim 2, the other radio communication device switches the plurality of frequency channels in the same order as the transmission channel switching means with a number of skips of 1 or more, and sets different frequency channels to the two receiving units. To do.

  According to the present invention, the wireless communication apparatus includes a pair of wireless communication devices that perform wireless communication using an arbitrary frequency channel selected from a plurality of common frequency channels, and the transmission side and the reception side switch the frequency channel. In addition, it is possible to improve the probability that the frequency channels match each other.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
As shown in FIG. 1, the wireless communication system according to the first embodiment of the present invention includes a wireless slave device 1, a wireless master device 2, and a sensor 3 such as a gas leak sensor. The wireless slave device 1 and the wireless master device 2 communicate with each other by using a specific low power radio wave. The wireless master device 2 is connected to the center device via a cellular phone modem and an exchange (not shown). Here, only one wireless slave unit 1 is provided, but a plurality of wireless slave units 1 may be provided.

  The wireless slave unit 1 is connected to the control unit 11 that controls the entire wireless slave unit and the control unit 11, and transmits data to the wireless master unit 2 from the antenna 13 using specific low-power radio waves. And a transmission unit 12.

  The wireless master device 2 is connected to the control unit 21 for controlling the whole wireless master device and the like, and receives data transmitted from the wireless slave device 1 by a specific low power radio wave via the antenna 23. And a receiving unit 22.

  The control unit 11 of the wireless slave unit 1 and the control unit 21 of the wireless master unit 2 are each composed of a microcomputer equipped with a CPU, a ROM, and a RAM, and each counts a reference clock generated by a clock generation unit (not shown). Generate information. Here, the time information of the wireless slave device 1 and the time information of the wireless master device 2 are time-matched when the wireless slave device 1 and the wireless master device 2 are installed. However, since the time information is generated by counting the reference clock individually thereafter, a deviation may occur due to a temperature difference in the installation environment between the wireless slave device 1 and the wireless master device 2.

  The control unit 11 of the wireless slave device 1 includes a transmission channel setting counter 11 a for setting the frequency channel of the transmission unit 12. Further, the control unit 21 of the wireless master device 2 includes a reception channel setting counter 21 a for setting the frequency channel of the reception unit 22.

The operation of the wireless communication system having the above configuration will be described.
When the detection signal of the sensor 3 is input to the control unit 11 of the wireless slave unit 1, the control unit 11 sets the transmission channel of the transmission unit 12 in the transmission channel setting counter 11a, and security information (message) corresponding to the detection signal. ) To the transmitter 12. The transmitter 12 puts a message on the radio wave of the set transmission channel and transmits from the antenna 13. Here, the transmission channels of the transmission unit 12 are set in the order of channels 1, 2,... N (ascending order). That is, transmission using channel 1, transmission using channel 2,... Transmission using channel n are performed in this order. Further, the sequential transmission of the n channels is repeated a predetermined number of times (eg, 3 times).

  On the other hand, the reception frequency channel of the reception unit 22 of the wireless master device 2 is in the same order (ascending order) as the transmission channel of the wireless slave device 1 and the number of jumps is 1. That is, reception using the channels 1, 3,..., 2, 4,. Then, the sequential reception of the n channels is always repeated.

  2 to 9 show the transmission channel, the reception channel, the gap between transmission and reception channels, the presence or absence of matching between transmission and reception channels, and the probability of matching in the present embodiment and the conventional system (reception) when n is 3 to 8, 10, and 12, respectively. It is a figure shown about what changed the channel to the reverse order of the transmission channel. Hereinafter, it demonstrates in order.

  As shown in FIG. 2, when n = 3, the wireless slave unit 1 transmits in the order of channels 1, 2, and 3 as shown below the column “transmission channel” in FIG. 2. The operation of performing is repeated a predetermined number of times. On the other hand, the wireless master device 2 constantly repeats the operation of sequentially receiving using the reception channel shown on the right side of the column marked “jump” in FIG. Here, when the time difference between the wireless slave unit 1 and the wireless master unit 2 is small, the “reception difference” is received in the order of channels 1, 3, 2 as shown in the column “0”. If the “reception shift” becomes “1”, the channels 2, 1 and 3 are received in this order. If the “reception shift” becomes “2”, the channels 3, 2 and 1 are received in this order. .

  Here, as shown by shading in FIG. 2, when “reception deviation” is “0”, channel 1, when “reception deviation” is “1”, channel 3, and “reception deviation” is “2”. In the case of channel 2, the transmission channel and the reception channel coincide with each other during one channel switching (“hit / loop” = 1 in the figure). In other words, any value of the reception deviation matches within the transmission channel switching period, so the probability of matching (“hit_rate” in FIG. 2) is 100%. On the other hand, in the case of the conventional system, the channel 2 when the “reception shift” is “0”, the channel 1 when the “reception shift” is “1”, and the channel when the “reception shift” is “2”. 3, since the transmission channel and the reception channel match, the probability of matching is 100%. That is, when n = 3, both the conventional system and the present embodiment are 100%.

  In the case of n = 4 (FIG. 3), since this embodiment is 75% compared with 50% of the conventional system, it is increased by 25%. In the case of n = 5 (FIG. 4), as in the case of n = 3, both the conventional system and this embodiment are 100%. In the case of n = 6 (FIG. 5), since this embodiment is 83% with respect to 50% of the conventional system, it is 33% up. In the case of n = 7 (FIG. 6), as in the case of n = 3 and 5, both the conventional system and this embodiment are 100%. In the case of n = 8 (FIG. 7), since this embodiment is 88% compared with 50% of the conventional system, it is increased by 38%. In the case of n = 10 (FIG. 8), since this embodiment is 90% with respect to 50% of the conventional system, it is increased by 40%. In the case of n = 12 (FIG. 9), since this embodiment is 92% with respect to 50% of the conventional system, it is 42% up.

  As described above, when n is an odd number, both the conventional system and the present embodiment are 100%, and there is no difference in probability. On the other hand, when n is an even number, it is fixed to 50% in the conventional system, whereas in this embodiment, it is 75% or more, and increases as n increases. That is, as n is an even number and the number of channels to be switched increases, the effect of increasing the probability with respect to the conventional system increases.

  Thus, according to the wireless communication system of the first embodiment of the present invention, the transmission side switches to the order of channels 1, 2,... N (ascending order), and the receiving side is the same ascending order as the transmission side. By switching the number of jumps to 1, the probability that the frequency channels match each other can be made 75% or more.

  In the above embodiment, the transmission channels are switched in ascending order from the lowest to the higher, but conversely, the transmission channels may be switched in the descending order from the higher to the lower. Further, the channels 1 to n may not be arranged in the order of frequency.

[Second Embodiment]
The second embodiment of the present invention is a wireless communication system capable of setting the probability when n is an even number to 100%. FIG. 10 is a diagram showing the configuration of the wireless communication system of this embodiment. In this figure, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  In the present embodiment, the configurations and operations of the wireless slave device 1 and the sensor 3 are the same as those in the first embodiment. On the other hand, the wireless master device 4 is connected to the control unit 41 for controlling the entire wireless master device and the like, and the data transmitted from the wireless slave device 1 by a specific low-power radio wave is transmitted to each antenna. The first receiving unit 42 and the second receiving unit 43 that receive via 44 and 45 are provided. The ROM of the control unit 41 is provided with first and second reception channel setting counters 41a and 41b for setting the frequency channels of the first and second reception units 42 and 43, respectively.

  In the wireless communication system having the above configuration, when the detection signal of the sensor 3 is input to the control unit 11 of the wireless slave unit 1 and security information is transmitted from the wireless slave unit 1, the transmission channel of the transmission unit 12 is set to channel 1. Switching to the order of 2, ... n (ascending order) is the same as in the first embodiment. On the other hand, in the wireless master device 4, the reception signals of the antennas 44 and 45 are input to the first reception unit 42 and the second reception unit 43, respectively. Here, the reception frequency channels of the first and second reception units 42 and 43 are transmitted by the control unit 41 based on the first and second reception channel setting counters 41a and 41b, respectively. In the same order (ascending order) and the number of jumps is 1. However, the reception channel of the first reception unit 42 and the reception channel of the second reception unit 43 are set to be different.

  FIG. 11 is a diagram showing a transmission channel, a reception channel, a gap between transmission and reception channels, whether or not transmission and reception channels match, and a probability of matching when n = 6. Here, A to F are cases where the deviation is 0 to 5, respectively. For the sake of convenience, the transmission channel is described as deviating from that of the first embodiment (FIG. 5). Further, here, the reception channel of the second reception unit 43 is advanced by 1/6 of the switching period with respect to the reception channel of the first reception unit 42.

  Comparing this figure with FIG. 5 (first embodiment), in the case of FIG. 5, when the deviation is 3, the transmission channel does not match the reception channel, so the probability is only 83%. Then, when the deviation is 3, the first reception unit 42 having the same reception channel setting as that of the reception unit 22 of the first embodiment does not match the transmission channel and the reception channel, but has a different reception channel setting. In the second receiving unit 43, since the transmission channel and the receiving channel match, the probability is 100% when both the first and second receiving units 42 and 43 are combined. 11A to 11F, it can be seen that the probability is 100% in all cases where the deviation is 0 to 5.

  As described above, according to the present embodiment, by providing two receiving units and making the reception frequency channels different, even when the number of channels is an even number, the value of the deviation between the transmission and reception channels becomes any value. The transmission channel and the reception channel always match. Therefore, the present invention is extremely effective for a security information transmission system that requires reliable information transmission.

It is a figure which shows the structure of the radio | wireless communications system of the 1st Embodiment of this invention. It is a figure which shows the presence or absence of the match of transmission, a reception channel, its shift | offset | difference, transmission, and a reception channel in case of n being 3 in 1st Embodiment of this invention, and a matching probability. It is a figure which shows the presence or absence of a match of transmission, a reception channel, its deviation, transmission, and a reception channel, and a matching probability in case of n being 4 in the 1st Embodiment of this invention. It is a figure which shows the presence or absence of a match of transmission, a reception channel, its deviation, transmission, and a reception channel, and a matching probability in case n is 5 in the 1st Embodiment of this invention. It is a figure which shows the presence or absence of a match of transmission, a reception channel, its deviation, transmission, and a reception channel, and a matching probability in case of n being 6 in the first embodiment of the present invention. It is a figure which shows the presence or absence of the coincidence of transmission, a reception channel, its deviation, transmission, and a reception channel, and the probability of coincidence when n is 7 in the first embodiment of the present invention. It is a figure which shows the presence or absence of the match of transmission, a reception channel, its deviation, transmission, and a reception channel when n is 8 in the 1st Embodiment of this invention, and a matching probability. It is a figure which shows the presence or absence of the match of transmission, a reception channel, its deviation, transmission, and a reception channel, and a matching probability in case of n = 10 in the 1st Embodiment of this invention. It is a figure which shows the presence or absence of the coincidence of a transmission, a reception channel, its deviation, transmission, and a reception channel when n is 12 in the 1st Embodiment of this invention, and a matching probability. It is a figure which shows the structure of the radio | wireless communications system of the 2nd Embodiment of this invention. It is a figure which shows the presence or absence of the match of transmission, a reception channel, its deviation, transmission, and a reception channel, and a matching probability in case the n is 6 in the 2nd Embodiment of this invention. It is a figure which shows the presence or absence of the match of transmission, a reception channel, its deviation, transmission, and a reception channel, and a matching probability at the time of switching a transmission and a reception channel in the same order in the conventional radio | wireless communications system. It is a figure which shows the presence or absence of the coincidence of transmission, a reception channel, its deviation, transmission, and a reception channel, and a coincidence when the transmission and reception channels are switched in reverse order in a conventional wireless communication system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Radio | wireless individual machine, 2 ... Radio | wireless master unit, 11, 21, 41 ... Control part, 11a ... Transmission channel setting counter, 12 ... Transmission part, 21a ... Reception channel setting Counter, 22... Reception unit, 41a... First reception channel setting counter, 41b... First reception channel setting counter, 42... First reception unit, 43. Receiver.

Claims (2)

In a wireless communication system including a pair of wireless communication devices that perform wireless communication using an arbitrary frequency channel selected from a plurality of common frequency channels,
One wireless communication device has a transmission channel switching means for switching the plurality of frequency channels in a predetermined order and setting the transmission unit, and the other wireless communication device has the number of jumps of one or more of the plurality of frequency channels. And a receiving channel switching means for switching to the same order as the transmitting channel switching means and setting in the receiving unit. The wireless communication system according to claim 1, wherein
The other wireless communication device has two reception units with different set frequency channels.

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