JP3465562B2 - Wireless data communication device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data communication device, and more particularly to an MCA (multi-channel access) type wireless data communication device for automatically selecting a use channel from a plurality of channels.

[0002]

2. Description of the Related Art Conventionally, in an MCA of a wireless data communication device, carrier sensing is performed according to a predetermined channel priority order, and when a channel without a carrier is selected, the channel is used as a used channel to establish a link. I have to.

[0003]

However, when a plurality of wireless data communication devices are used for communication in the same area, mutual interference may adversely affect each other, and therefore, simply in advance. In the conventional example in which carrier sense is performed in a predetermined priority order to select a channel to be used, the radio wave of the selected channel is added, the channel that has been used until then becomes unusable due to mutual interference, or there is no carrier. However, there is a drawback in that channels may not be able to communicate due to mutual interference.

Even if the wireless data communication device is installed at the same place, the amount of space attenuation is often different depending on the channel (frequency), and it is desirable to select a channel with low attenuation and good transmission quality.

The present invention has been made in view of the above points, and provides a wireless data communication apparatus capable of performing stable communication by selecting a good channel with little mutual interference and good transmission quality. The purpose is to do.

[0006]

In order to achieve the above-mentioned object, the present invention is constructed as follows.

That is, the wireless data communication apparatus of the present invention according to claim 1 is a wireless data communication apparatus which automatically selects a use channel to be used for communication from a plurality of channels, and a carrier detection circuit for detecting a carrier and a detection circuit. A level detection circuit for detecting the level of the generated carrier,
Based on the detection output of the two detection circuits, together when and a channel selection means for selecting the channel to be used
In addition, the channel selection means is a channel with carrier.
Deselect the channel and select the channel with no carrier.
To the extent that there is a possibility of mutual interference from other carriers.
Correspondingly prioritize and potentially interfere with each other.
Select the least used channel as the used channel
It

The wireless data communication apparatus according to the present invention of claim 2 is a use channel used for communication from a plurality of channels.
A wireless data communication device that automatically selects
Carrier detection circuit for detecting a carrier and the carrier detection circuit
No carrier detected based on circuit detect output
Measuring means for measuring the communication quality of the selected channel and the measurement
Select the channel to be used based on the measurement result of the means
And a channel selecting means for performing the measurement.
Means send and receive on channels where no carrier was detected
The error rate is measured by performing the communication.
The channel selection means selects the channel with a low error rate
It is the one you choose as a channel.

The wireless data communication apparatus according to the present invention of claim 3
In the configuration of claim 2, the measuring means is a carrier.
A is received and sent and received on the channel that was not detected.
Measuring the level, the channel selecting means
Is the channel with the highest reception level
To choose as.

[0010]

[0011]

According to the present invention of claim 1, the use channel is selected based on both the detection outputs of the carrier detection circuit and the level detection circuit. By comparison, a channel with better communication quality can be selected.

According to the present invention of claim 2, the carrier is detected.
Measure the communication quality of the channels that were not issued and
Since the used channel is selected based on the result, communication quality
You can select a good channel. Also, measure the error rate
Communication channel with low error rate
You can select channels with good quality.

According to the present invention of claim 3, the reception level is
Since it is measured and the channel to be used is selected, there is little attenuation.
Channels with good signal quality can be selected.

[0015]

[0016]

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

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

In the communication system of this embodiment, a master station 3 comprising a wireless data communication device of the present invention connected to a control device 1 such as a personal computer via an RS-232C cable 2.
And a slave station 5 composed of the wireless data communication device of the present invention connected to the terminal device 4 via the RS-232C cable 2, respectively, and wirelessly communicates between the stations. Then, for example, the sales data of the terminal device 4 such as an automatic vending machine is collected in the control device 1 via each slave station 5 and the master station 3.

(Embodiment 1) FIG. 2 is a block diagram of a main part of a wireless data communication apparatus constituting the master station 3 or the slave station 5 of FIG.

The wireless data communication apparatus of this embodiment is
A receiving circuit 7 to which a received signal from the antenna 6 is given,
A detection circuit 8 for detecting the output of the reception circuit 7, a binarization circuit 9 for binarizing the output of the detection circuit 8 and outputting it as reception data, and the reception data and detection circuit 8 from the binarization circuit 9. The output of an S meter (signal meter) as a reception level detection circuit in the inside and a sense output corresponding to the presence or absence of a carrier from the carrier detection circuit in the detection circuit 8 are given, and the MPU 10 as a control circuit for controlling communication is provided. A low-pass filter 11 to which transmission data from the MPU 10 is given and a transmission circuit 12 that modulates the output of the low-pass filter 11 are provided.

Although not shown, this wireless data communication device is provided with a switch for setting whether to operate as a master station or a slave station, the control device 1 or the terminal device 4 in FIG. An RS-232C connector for connecting via the RS-232C cable 2 and an interface circuit thereof are provided.

In this embodiment, in order to select a good channel with less mutual interference as a use channel and to enable stable communication, the sense output corresponding to the presence or absence of a carrier and the level of the carrier are supported. Based on the output of the S meter, the MPU 10 as the channel selecting means selects a channel that is least likely to receive mutual interference as a used channel as described later.

That is, in this embodiment, the optimum use channel is selected from a plurality of data channels from CH1 to CH9 as follows.

First, carrier sensing is performed on all the data channels from CH1 to CH9. When there is a carrier, the carrier level is measured, and the level is compared with a predetermined threshold value. In the form, it is discriminated into four levels from level 0 to level 3,
Based on these, first, the channel with a carrier is deselected, and the priority order is determined according to the degree of possibility of mutual interference, and the channel with the least possibility of mutual interference is set as the used channel. It is something to choose.

In this embodiment, the "non-selection priority order" from the order 1 to the order 6 is determined as follows in the order of high possibility of receiving mutual interference such as sensitivity suppression and intermodulation. In addition, each channel of CH1-CH9,
They are provided at constant frequency intervals, and CH9 has a higher frequency.

(1) The channel of non-selection priority 1 is
When there are at least two channels whose carrier level is level 3, CH1, CH
If it is 2, 2xCH1-CH2, 2xCH2-CH
It is a channel calculated as 1 or (CH1 + CH2) / 2, and this channel is a channel that is greatly affected by intermodulation.

(2) If the carrier level of the non-selected channel 2 is at least one channel of level 2 and one channel of level 3, the channels are designated as CH1 and CH2, respectively.
XCH1-CH2, 2xCH2-CH1, or
It is a channel calculated as (CH1 + CH2) / 2, and is a channel that is greatly affected by intermodulation.

(3) The channel of the non-selection priority order 3 is
When there are at least two channels whose carrier level is level 2, CH1, CH
If it is 2, 2xCH1-CH2, 2xCH2-CH
It is a channel calculated as 1 or (CH1 + CH2) / 2, and this channel is a channel that is greatly affected by intermodulation.

(4) The channel of non-selection priority order 4 is
It is a channel adjacent to a channel whose carrier level is level 3, and is a channel which is greatly affected by sensitivity suppression.

(5) Channels with non-selection priority 5
It is a channel next to the channel whose carrier level is level 2, and is a channel in which the influence of sensitivity suppression is medium.

(6) The channel of non-selection priority 6 is
It is a channel adjacent to a channel whose carrier level is level 1, and is a channel which is less affected by sensitivity suppression.

In this embodiment, first, a channel in which a carrier is detected is excluded, and if there is a channel that does not correspond to any of the non-selection priority orders 1 to 6, that channel is likely to receive mutual interference. The channel is selected as the used channel because it is the smallest channel, and if there is no channel that does not correspond to any of the non-selection priorities 1 to 6, the lowest channel of the non-selection priority is selected as the used channel. It is a thing.

When one channel corresponds to a plurality of non-selection priorities, for example, non-selection priority 2 and non-selection priority 5, the higher order, for example non-selection priority 2, is selected. This is to be the non-selection priority of channels.

When there are a plurality of channels to be selected as used channels, the channels are selected in a predetermined priority order as in the conventional example.

Hereinafter, the procedure for selecting a channel to be used will be described based on a concrete example with reference to Tables 1 and 2 below.

In each table, the presence / absence of carriers is indicated by "1" and "0", the corresponding non-selection priority order is indicated by ⊚, and the non-selection priority order of channels not selected by the existence of carriers is indicated. In addition, it is indicated by ×, and the predetermined priority order 1 to 9 similar to the conventional example is shown, and the channel finally selected as the used channel is ◎.
It shows with.

First, Table 1 shows an example in which there are two data channels having carriers, 3CH and 7CH, the carrier level of 3CH is level 3, and the carrier level of 7CH is level 2. Shows.

In this case, the level 3 channel is 1
Since there is only one, there is no channel corresponding to non-selection priority 1, and the channel corresponding to non-selection priority 2 is
(CH1 + CH2) / 2 = (3 + 7) / 2 = 5CH corresponds, and the non-selection priority 3 is 1 for the level 2 channel.
Since there is only one channel, there is no corresponding channel, and the non-selection priority 4 is 2CH and 4CH which are the channels next to 3CH.
, And non-selection priority 5 is next to 7CH 6
CH and 8CH correspond to each other, and the non-selection priority order 6 has no level 1 channel, so that there is no corresponding channel.

In this case, since there are two channels, 1CH and 9CH, which do not correspond to any of the non-selection priorities 1 to 6, 1CH of priority 1 is selected in accordance with a predetermined priority. It is a thing.

[0041]

[Table 1]

Further, Table 2 shows that there are four data channels having carriers, 1CH, 4CH, 6CH and 9CH, the carrier level of 1CH and 4CH is level 3, and the carrier level of 6CH is level 1. And 9
An example in which the carrier level of CH is 2 is shown.

In this case, the non-selection priority 1 is 2 ×
CH2-CH1 = 2 × 4-1 = 7CH corresponds, and the non-selection priority 2 is (CH1 + CH2) / 2 = (1 + 9) /
2 = 5CH, non-selection priority 3 has no corresponding channel, and non-selection priority 4 is next to 1CH 2
3CH and 5CH that are adjacent to CH and 4CH correspond, and 8CH that is adjacent to 9CH corresponds to non-selection priority 5,
The non-selection priority 6 corresponds to 5CH and 7CH adjacent to 6CH.

In this case, since there is no channel that does not correspond to any of the non-selection priority orders 1 to 6, the lowest channel of the non-selection priority order, that is, 8C.
H will be selected.

When one channel corresponds to a plurality of non-selection priorities, the higher order is the non-selection priority as described above. For example, in Table 2, the non-selection priority is given. The non-selection priority order of 7CH corresponding to the orders 1 and 6 is determined as "1".

[0046]

[Table 2]

FIG. 3 is a flowchart for explaining the above operation. First, selection of a data channel is started (step n1), carrier sense is performed to judge whether or not there is a carrier (step n2), If there is a carrier, measure its reception level (step n3),
Whether or not all channels have been confirmed is determined (step n4). When all channels have been confirmed, the optimum data channel is selected based on the above-mentioned determination of non-selection priority order (step n5), and data is selected. This completes the channel selection (step n).
6).

Thus, for all channels,
In the channel with carrier by performing carrier sense, the reception level is measured, and based on them, the priority is determined according to the degree of the possibility of receiving mutual interference and the channel is selected. The channel that is least likely to be received can be selected as the used channel.

(Second Embodiment) FIG. 4 is a block diagram of an essential part of another embodiment of the present invention, in which parts corresponding to those in FIG. 2 are designated by the same reference numerals.

In this embodiment, when a data channel is vacant, the presence or absence of a carrier is dealt with in order to select the data channel with the best communication quality as the used channel and to perform stable communication. Based on the sense output, the MPU _{10 1} as the measuring unit and the channel selecting unit measures the communication quality of the channel in which no carrier is detected, and selects the optimum channel as the used channel based on the measurement result. In the data channel in which the carrier is not detected, pseudo bit transmission / reception is performed to measure the bit error rate (BER), and the data channel with the smallest bit error rate is selected as the used channel.

That is, in this embodiment, when carrier sense is performed and there is no carrier, a link establishing operation is performed, and after the link is established, the partner station is requested to transmit a pseudo random code for bit error rate measurement. In response to this, the pseudo-random code sent from the partner station is received and compared in synchronization to measure the bit error rate and then the link is disconnected, and the carrier is not detected. This is performed for all data channels, and the data channel with the smallest bit error rate is selected as the used channel.

FIG. 5 is a flow chart for explaining the above operation. First, selection of a data channel is started (step n1), carrier sense is performed to judge whether or not there is a carrier (step n2), When there is no carrier, the link is established (step n3), the bit error rate is measured (step n4), and the measured value is compared with the minimum value measured so far by starting the data channel selection operation. (Step n5) If the measured value is lower than the minimum value, the measured value is updated as a new minimum value (Step n6), and it is judged whether or not all channels are confirmed (Step n7). If it is confirmed, the channel with the minimum bit error rate is selected as the used channel (step n8), and the It is intended to complete the selection of the channel (step n9). In step n5,
When the measured value is not smaller than the minimum value, the process proceeds to step n7 without replacing the minimum value.

In this manner, since the bit error rate is measured by performing pseudo transmission / reception for the empty channels of all the data channels, and the data channel with the lowest bit error rate is selected as the used channel, the communication quality is good. Stable communication can be performed on various channels.

(Third Embodiment) FIG. 6 is a block diagram of an essential part of still another embodiment of the present invention, in which parts corresponding to those in FIG. 4 are designated by the same reference numerals.

In the above-mentioned embodiment, when the data channel is vacant, the bit error rate is measured in order to select the data channel having the best communication quality as the used channel, but in this embodiment, The reception level is measured, and the data channel with the highest reception level is selected as the used channel.

In this embodiment, the MPU 10 ₂ as the measuring means and the channel selecting means measures the communication quality of the channel in which the carrier is not detected based on the sense output corresponding to the presence or absence of the carrier, and the measurement result is obtained. Based on the above, the optimum channel is selected as the used channel.For the data channels for which no carrier is detected, pseudo reception and transmission are performed to measure the reception level, and the data channel with the highest reception level is set as the used channel. To choose.

That is, in this embodiment, when carrier sense is performed and there is no carrier, a link establishing operation is performed, and after the link is established, the partner station is requested to send out a constant signal for measuring the reception level. In response to, receive the signal sent from the other station and measure the received level,
This is performed for all data channels for which no carrier has been detected, and the data channel with the highest reception level is selected as the used channel.

FIG. 7 is a flow chart for explaining the above operation. First, selection of a data channel is started (step n1), carrier sense is performed to judge whether or not there is a carrier (step n2), When there is no carrier, a link is established (step n3), the reception level is measured (step n4), and the measured value and the maximum value of the reception level measured so far are started. When the measured value is larger than the maximum value by comparison (step n5), the measured value is updated as a new maximum value (step n6), and it is judged whether or not all channels are confirmed (step n7). When the channel is confirmed, the channel with the maximum reception level is selected as the used channel (step n8), and the data is It is intended to complete the selection of Yan'neru (step n9). When the measured value is not larger than the maximum value in step n5, the maximum value is not replaced and the process proceeds to step n7.

In this way, the reception level is measured by performing pseudo transmission / reception with respect to the empty channels of all the data channels, and the data channel with the largest reception level and the least attenuation is selected as the use channel.
Stable communication can be performed on a channel with good communication quality.

(Other Embodiments) As other embodiments of the present invention, the above-described embodiments may be combined. For example, in the first embodiment, Table 1 or Table 2 may be used.
In place of the predetermined priority shown in FIG.
The bit error rate may be selected or the priority may be selected according to the reception level of the second embodiment.

In each of the above-mentioned embodiments, the reception level and the bit error rate are measured for all the data channels to select the optimum channel, but it is not always necessary to perform it for all the channels.

Although the above embodiment is applied to the selection of the data channel, the present invention is not limited to the data channel and may be applied to the control channel or the like.

[0063]

As described above, according to the present invention, it is possible to select a channel having a better communication quality as compared with the conventional example in which the used channel is simply selected depending on the presence or absence of a carrier, and mutual interference is achieved. Since a channel that is less likely to be received is selected as a used channel, it is possible to select a good channel that is less affected by sensitivity suppression and intermodulation.

Further, since the communication quality such as the error rate and the reception level of the channel in which the carrier is not detected is measured and the used channel is selected based on the result, the channel having the good communication quality is selected and stabilized. Communication can be performed.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a main part of the wireless data communication device of FIG.

3 is a flowchart for explaining the operation of FIG.

FIG. 4 is a block diagram of a main part of another embodiment of the present invention.

5 is a flowchart for explaining the operation of FIG.

FIG. 6 is a block diagram of a main part of still another embodiment of the present invention.

7 is a flowchart for explaining the operation of FIG.

[Explanation of symbols]

7 reception circuit 8 detection circuit 10, 10 ₁ , 10 ₂ MPU 12 transmission circuit

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Claims (3)

(57) [Claims] 1. A wireless data communication device for automatically selecting a use channel to be used for communication from a plurality of channels, a carrier detection circuit for detecting a carrier, and a level detection circuit for detecting the level of the detected carrier. Channel selecting means for selecting the used channel based on the detection outputs of both detection circuits , wherein the channel selecting means is a channel with a carrier.
Deselect and for channels with no carrier
Corresponds to the degree of possibility of mutual interference from other carriers
Priorities to determine the highest likelihood of mutual interference.
A wireless data communication device characterized by selecting a small number of channels as used channels . 2. In a wireless data communication device for automatically selecting a use channel to be used for communication from a plurality of channels, a carrier detection circuit for detecting a carrier and a carrier detection circuit based on a detection output of the carrier detection circuit. The measuring means for measuring the communication quality of the channel which has not been performed, and the channel selecting means for selecting the use channel based on the measurement result of the measuring means, and the measuring means is a channel in which the carrier is not detected. The wireless data communication device is characterized in that the channel selection means selects a channel having a low error rate as the use channel by performing transmission / reception in accordance with the above. 3. The measuring means transmits and receives on a channel in which no carrier is detected to measure a reception level, and the channel selecting means selects a channel having a high reception level as the use channel. The wireless data communication device according to claim 2.