JPH11136732A - Radio data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select the channel of satisfactory transmission quality with less mutual interference and to execute stable communication by detecting the level of a detected carrier and selecting the use channel based on the detected output. SOLUTION: A reception signal from an antenna 6 is given to a reception circuit 7. A detection circuit 8 detects the output of the reception circuit 7. A binarization circuit 9 binarizes the output of detection circuit 8 and outputs it as reception data. MPU 10 as a control circuit controls communication since reception data from the binarization circuit 9, the output of an S meter (signal meter) as the reception level detection circuit in the detection circuit 8 and sense output corresponding to the presence or absence of a carrier from a carrier detection circuit are given. Namely, MPU 10 selects the channel having the lowest possibility for receiving mutual interference as the use channel based on the sense output corresponding to the presence or absence of the carrier and the output of the S meter, which corresponds to the level of the carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wireless data communication device, and more particularly, to an MCA (multi-channel access) 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 apparatus, carrier sense is performed according to a predetermined channel priority, and when a channel having no carrier is selected, a link is established using that channel as a used channel. I have to.

[0003]

However, in the case where communication is performed using a plurality of wireless data communication devices in the same area, mutual interference adversely affects each other. In the conventional example in which a carrier sense is performed in a predetermined priority and a channel to be used is selected, a channel that has been used until then becomes unusable due to mutual interference due to the addition of radio waves of the selected channel, or there is no carrier. There is a drawback that communication may not be possible even on a channel due to mutual interference.

[0004] Even if the wireless data communication devices are installed in the same place, the amount of space attenuation often differs depending on the channel (frequency), and it is desirable to select a channel with little 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 configured as follows.

That is, according to the first aspect of the present invention, there is provided a wireless data communication apparatus for automatically selecting a use channel to be used for communication from a plurality of channels. A level detection circuit for detecting the level of the selected carrier, and channel selection means for selecting the use channel based on the detection outputs of the two detection circuits.

According to a second aspect of the present invention, in the wireless data communication apparatus according to the first aspect, each of the detection circuits detects all of the plurality of channels. A channel that is less likely to receive the channel is selected as the use channel.

According to a third aspect of the present invention, there is provided a wireless data communication apparatus for automatically selecting a use channel to be used for communication from a plurality of channels in a wireless data communication apparatus. Measuring means for measuring the communication quality of the channel on which no carrier has been detected, based on the detection output of the carrier detection circuit;
Channel selecting means for selecting the use channel based on the measurement result of the measuring means.

According to a fourth aspect of the present invention, in the wireless data communication apparatus according to the third aspect, the measuring means measures an error rate by performing transmission and reception on a channel on which no carrier is detected. Channel selection means,
A channel having a low error rate is selected as the used channel.

According to a fifth aspect of the present invention, in the wireless data communication apparatus according to the third aspect, the measuring means performs transmission and reception on a channel on which no carrier is detected to measure a reception level. The channel selection means selects a channel having a high reception level as the use channel.

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

According to the second aspect of the present invention, each detection circuit detects all the channels and selects a channel which is less likely to be subjected to mutual interference as a used channel. A good channel which is less affected by intermodulation can be selected.

According to the third aspect of the present invention, since the communication quality of the channel for which no carrier is detected is measured and the channel to be used is selected based on the result, a channel with good communication quality can be selected.

According to the present invention, since the error rate is measured and the channel to be used is selected, a channel having a low error rate and good communication quality can be selected.

According to the fifth aspect of the present invention, since the channel to be used is selected by measuring the reception level, it is possible to select a channel with little attenuation and good communication quality.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

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

The communication system according to this embodiment comprises a master station 3 comprising a wireless data communication apparatus of the present invention connected to a control apparatus 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 for wireless communication between the stations. Here, for example, the sales data of the terminal device 4 such as a 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 slave station 5 in FIG.

The wireless data communication apparatus according to this embodiment
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, a reception data from the binarization circuit 9 and the detection circuit 8 An 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 a carrier detection circuit in the detection circuit 8 are provided, and an MPU 10 as a control circuit for controlling communication is provided. And a transmission circuit 12 for modulating the output of the low-pass filter 11 to which the transmission data from the MPU 10 is applied.

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

In this embodiment, a sense output corresponding to the presence or absence of a carrier and a carrier level corresponding to the carrier level are selected in order to select a good channel with little mutual interference as a used channel so that stable communication can be performed. Based on the output of the S-meter, the MPU 10 as a channel selecting means selects a channel which is least likely to receive mutual interference as a channel to be used as described later.

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

First, carrier sense is performed for all data channels from CH1 to CH9, and when there is a carrier, the level of the carrier is measured, and the level is compared with a predetermined threshold value, and a plurality of steps are performed. In the form, it is determined in four stages from level 0 to level 3,
Based on these, first, a channel with a carrier is deselected, and a priority is determined according to a degree of possibility of mutual interference, and a channel with the least possibility of mutual interference is used as a used channel. To choose.

In this embodiment, the "non-selection priorities" are determined as follows from the order 1 to the order 6 in descending order of the possibility of mutual interference such as sensitivity suppression and intermodulation. In addition, each channel of CH1 to CH9 is
They are provided at a constant frequency interval, 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, the channels are set to CH1, CH
Assuming that 2, 2 × CH1-CH2, 2 × CH2-CH
1 or a channel calculated as (CH1 + CH2) / 2, and this channel is a channel that is greatly affected by intermodulation.

(2) The non-selection order channel 2 has a carrier level of CH1 and CH2 when there are at least one level 2 channel and at least one level 3 channel.
× CH1-CH2, 2 × CH2-CH1, or
This is a channel calculated as (CH1 + CH2) / 2, and is a channel that is greatly affected by intermodulation.

(3) Non-selection priority 3 channels are:
When there are at least two channels whose carrier levels are level 2, the channels are set to CH1, CH
Assuming that 2, 2 × CH1-CH2, 2 × CH2-CH
1 or a channel calculated as (CH1 + CH2) / 2, and this channel is a channel that is greatly affected by intermodulation.

(4) The channel of the non-selection priority order 4 is
The channel adjacent to the channel whose carrier level is level 3 is a channel that has a large influence of sensitivity suppression.

(5) The channel of non-selection priority 5 is
The channel adjacent to the channel whose carrier level is level 2 is a channel whose influence of sensitivity suppression is moderate.

(6) The channel of non-selection priority 6 is
The channel whose carrier level is adjacent to the channel whose level is 1 is a channel on which the influence of sensitivity suppression is small.

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 priorities 1 to 6, the channel may be subject to mutual interference. The channel having the least number of non-selection priorities is selected as the used channel if there is no channel that does not correspond to any of the non-selection priorities 1 to 6 because the channel is regarded as the least number of channels. Things.

In the case where one channel corresponds to a plurality of non-selection priorities, for example, non-selection priority 2 and non-selection priority 5, a higher order, for example, non-selection priority 2 is assigned to that channel. This is a non-selection priority of the channel.

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

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

In each table, the presence / absence of a carrier is indicated by “1” or “0”, the corresponding non-selection priority is indicated by ◎, and the non-selection priority of a channel not selected due to the presence of a carrier is indicated. The channel is indicated by ×, and furthermore, predetermined priorities 1 to 9 as in the conventional example are shown, and the channel finally selected as the used channel is represented by ◎.
Indicated by.

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

In this case, the level 3 channel is 1
Since there is only one channel, there is no channel corresponding to the non-selection priority 1 and the channel corresponding to the non-selection priority 2
(CH1 + CH2) / 2 = (3 + 7) / 2 = 5CH, and the non-selection priority 3 indicates that the level 2 channel is 1
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 the non-selection priority 5 is 6 next to 7CH.
CH and 8CH correspond, and the non-selection priority 6 does not have a corresponding channel because there is no level 1 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 according to a predetermined priority. Things.

[0041]

[Table 1]

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

In this case, the non-selection priority 1 is 2 ×
CH2-CH1 = 2 × 4-1 = 7CH, 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 adjacent to CH and 4CH correspond, and the non-selection priority 5 corresponds to 8CH adjacent to 9CH,
The non-selection priority 6 corresponds to 5CH and 7CH next to 6CH.

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

In the case where one channel corresponds to a plurality of non-selection priorities, as described above, the higher order is set as the non-selection priority. The non-selection priority of 7CH corresponding to the ranks 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), and carrier sense is performed to determine whether or not there is a carrier (step n2). If there is a carrier, the reception level is measured (step n3),
It is determined whether all channels have been confirmed (step n4). If all channels have been confirmed, an optimal data channel is selected (step n5) based on the above-described non-selection priority determination and the like. This completes the channel selection (step n).
6).

As described above, for all the channels,
Carrier sensing is performed on a channel with a carrier to measure the reception level, and based on the measured reception levels, a priority is determined according to the degree of possibility of mutual interference and a channel is selected. The channel that is least likely to be received can be selected as the used channel.

(Embodiment 2) FIG. 4 is a block diagram of a main part of another embodiment of the present invention, and portions corresponding to FIG. 2 are denoted by the same reference numerals.

In this embodiment, when a data channel is available, a data channel having the best communication quality is selected as a used channel so that stable communication can be performed. based on the sense output, MPU 10 ₁ as the measurement means and channel selection means, in which the carrier measures the communication quality of the channel has not been detected, on the basis of the measurement result is selected as a use channel optimum channel In a data channel in which a carrier is not detected, transmission and reception are performed in a pseudo manner, a bit error rate (BER) is measured, and a data channel having the least bit error rate is selected as a used channel.

That is, in this embodiment, when there is no carrier due to carrier sense, a link establishment operation is performed, and after link establishment, a request is made to the partner station to transmit a pseudo random code for bit error rate measurement. In response, the pseudo-random code sent from the partner station is received, synchronized and compared to measure the bit error rate and then disconnect the link. This is performed for all the data channels, and the data channel with the lowest bit error rate is selected as the used channel.

FIG. 5 is a flowchart for explaining the above operation. First, selection of a data channel is started (step n1), and carrier sense is performed to determine 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 up to the start of 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 determined whether or not all the channels have been confirmed (Step n7). If confirmed, the channel with the minimum bit error rate is selected as the used channel (step n8), It is intended to complete the selection of the channel (step n9). In step n5,
If the measured value is not smaller than the minimum value, the process proceeds to Step n7 without replacing the minimum value.

As described above, pseudo error transmission / reception is performed for the vacant channels of all data channels to measure the bit error rate, and the data channel having the lowest bit error rate is selected as the used channel. Stable communication can be performed on the appropriate channel.

(Embodiment 3) FIG. 6 is a block diagram of a main part of still another embodiment of the present invention, and portions corresponding to FIG. 4 are denoted by the same reference numerals.

In the above-described 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 channel to be used. The reception level is measured, and the data channel having the highest reception level is selected as the used channel.

[0056] In this embodiment, on the basis of the sense output corresponding to the presence or absence of the carrier, MPU 10 ₂ as the measurement means and channel selection means, the carrier measures the communication quality of the channel is not detected, the result of the measurement Based on the data channel, the most suitable channel is selected as the used channel. For the data channel for which no carrier is detected, the transmission level is simulated, the reception level is measured, and the data channel with the highest reception level is used as the used channel. Choose.

That is, in this embodiment, when there is no carrier after performing carrier sense, a link establishment operation is performed, and after the link is established, a request is made to the partner station to transmit a certain signal for measuring the reception level. Receives the signal sent from the other station in response to and measures the reception 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 flowchart for explaining the above operation. First, selection of a data channel is started (step n1), and carrier sense is performed to determine 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 by starting the data channel selecting operation are started. If the measured value is larger than the maximum value (step n5), the measured value is updated as a new maximum value (step n6), and it is determined whether or not all the channels have been confirmed (step n7). When the channel is confirmed, the channel having the maximum value of the reception level is selected as the used channel (step n8), 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 process proceeds to step n7 without replacing the maximum value.

As described above, the reception level is measured by performing pseudo transmission / reception for all the available channels of the data channels, and the data channel having the largest reception level and the least attenuation is selected as the used channel.
Stable communication can be performed on a channel with good communication quality.

(Other Embodiments) As another embodiment of the present invention, the above embodiments may be combined. For example, in Embodiment 1, Table 1 or Table 2 may be used.
Instead of the predetermined priority shown in FIG.
Or a priority order according to the reception level of the second embodiment.

In each of the above 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 the measurement for all the channels.

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

[0063]

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

Further, the communication quality such as the error rate and the reception level of the channel in which no carrier is detected is measured, and the channel to be used is selected based on the result. Communication can be performed.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a main part of the wireless data communication device of FIG. 1;

FIG. 3 is a flowchart for explaining the operation of FIG. 2;

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

FIG. 5 is a flowchart for explaining the operation of FIG. 4;

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

FIG. 7 is a flowchart for explaining the operation of FIG. 6;

[Explanation of symbols]

7 receiving circuit 8 detecting circuit 10,10 ₁ , 10 ₂ MPU 12 transmitting circuit

Claims (5)

[Claims] 1. A wireless data communication apparatus for automatically selecting a use channel to be used for communication from a plurality of channels, a carrier detection circuit for detecting a carrier, a level detection circuit for detecting a level of the detected carrier, A wireless data communication device comprising: a channel selecting unit that selects the use channel based on detection outputs of the two detection circuits. 2. Each of the detection circuits detects all of the plurality of channels, and the channel selection means selects a channel which is less likely to receive mutual interference as the used channel. The wireless data communication device according to claim 1. 3. A wireless data communication apparatus for automatically selecting a use channel to be used for communication from a plurality of channels, wherein a carrier is detected based on a detection output of the carrier detection circuit and the carrier detection circuit. A wireless data communication apparatus comprising: a measuring unit that measures communication quality of a channel that is not performed; and a channel selecting unit that selects the use channel based on a measurement result of the measuring unit. 4. The measuring means performs transmission and reception on a channel on which no carrier is detected to measure an error rate, and the channel selecting means selects a channel having a low error rate as the used channel. 4. The wireless data communication device according to claim 3, wherein 5. The measuring means for performing transmission and reception on a channel on which no carrier is detected to measure a reception level, and the channel selection means for selecting a channel having a high reception level as the used channel. The wireless data communication device according to claim 3, wherein