JPS6218129A - Radio paging communication system - Google Patents

Abstract

PURPOSE:To attain talking without interference by forming a radio channel by the control using the multi-channel access technology and switching the frequency to other frequency group at radio wave disturbance so as to recover the talking thereby forming an independent channel at each of optional number of radio equipments. CONSTITUTION:When an interference radio wave close to a transmission frequency f1 of a portable radio equipments 9 is generated, an interference detector DT of a base station 8 detects it, the information is transmitted to a control channel control section CONT. A CPU in the control section uses an outgoing control channel time slot T9 to the radio equipment 9 to give an instruction of a new channel CH designation signal thereby switching the frequency from a frequency f1 to a frequency g1. A base station 8 receives anew channel CH switching end signal from the radio equipment 9 at a control channel fc2, changes the reception frequency of a receiver Rx9 from the frequency f1 to the frequency g1 to bring the mode to the reception state. Similar operation is applied to other portable radio equipments 10-160. If the frequency g1 has disturbance, other frequency h1 is assigned.

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to wireless communication using weak radio waves, which is mainly used at construction sites such as construction and civil engineering work, between a large number of workers or between a work leader and workers. It relates to communication systems.

(Prior art and its problems) In these construction works, it is necessary for many construction workers to jointly carry out dangerous construction work, and during construction, the construction commander may give instructions to the workers, or the construction workers may Communicating between people is essential for ensuring work safety, and for this reason, wireless paging communication systems have been used for some time.

The outline of this system is shown in Figure 1, which normally uses a portable radio (for example 2) near the site, but it also uses commands issued by the construction commander who may be located at the radio base station 1, and the actual construction work. Mobile radio equipment (
For example, communication is performed using 3 to 7).

The basics of the system are simultaneous transmission and reception, and continuous transmission, and the portable radio is used hands-free. A system is made up of multiple slave stations that mainly use portable radios under a master station (wireless base station). If calls are rarely used between the master station and portable radios, it is possible to accommodate a large number of portable radios.
The mobile radios in a group use the same frequency, and when one mobile radio is transmitting, the other mobile radios do not talk and wait for transmission, so that one frequency is shared by multiple stations. ing.

The service area is usually approximately 75 meters in radius from the master station antenna, but if a larger service area is required, use antenna distribution or various repeaters (distributed transceiver, bidirectional booster, etc.) to cover a wide area. A service area can be secured.

In tunnels, buildings, etc., open cables such as the leaky coaxial cable 2 open coaxial cable can be used to obtain the required service area.

In addition, if calls are often used between the master station and the mobile radio, the mobile radios in the group may be able to transmit radio waves at two frequencies, for example, so that one frequency is used by another mobile radio. A method that uses a somewhat high-end portable radio that switches to a different frequency and transmits when there is a radio station is also in use.

However, in all of the above conventional systems shown in Figure 1, the number of channels that can be used for wireless transmission and reception, that is, the frequency of the radio waves that can be transmitted, is limited to one or two waves as described above in the portable radio equipment owned by construction workers. There were very limited numbers. This was done for economical reasons, or to avoid increasing the size of the portable device, since the number of crystal oscillators used in the original oscillator was in one-to-one correspondence with the transmission frequency. This is because the number of crystal oscillators is usually limited to two or less in order to prevent this.

If construction workers are using such systems,
Instructions from a leader who supervises multiple workers can be received by each portable radio, but when a worker wants to respond himself, he must use radio waves when other portable radios are not responding to prevent interference. I needed to find out when the person was not available and respond. Otherwise, if many workers were to use their portable radios at the same time, the transmission frequency would be two channels at most, so even if one or two workers could communicate, it would be more than 3 Å. At that time, there was no channel, which caused interference and made it impossible to communicate smoothly.

Furthermore, when a portable radio has two radio channels, the user must manually switch the channel of the portable radio, such as switching channel 1 to channel 2, which is inconvenient for construction work. There was also a problem in terms of safety.

Furthermore, due to the high frequency of use between the master station and portable radio equipment, and due to the necessity of construction safety, workers are required to listen to the conductor's instructions at all times, and other workers are also able to communicate with the conductor through calls. Individual workers may be required to monitor the content and use it as a reference for their work, and to be able to communicate with the conductor or other workers whenever necessary. In this case, the system configuration is unavoidably complicated and economically expensive as described below.

In other words, in order to prevent interference, each construction worker should carry a portable radio device with a different transmission frequency (that is, a different type of portable radio device), and communicate using the frequency allocation shown in Figure 2 (a). need to be done. In this case, in order to vary the frequency of radio waves transmitted from the portable radio, a different type of crystal oscillator is installed inside the portable radio, and circuit constants and
Since the adjustment methods are different from others, there are many factors that lead to increased prices, such as complicated parts arrangement, complicated design drawings, and uneven adjustment methods when manufacturing portable radio equipment.

In addition to the economically disadvantageous situation described above, Figure 2 (a)
The system shown in 2013 had an essential drawback of being vulnerable to radio interference from other systems.

That is, since the number of radio wave frequencies used is large (total of 5 waves in FIG. 2(a)), it is easily understood that this system is vulnerable to interference from other systems. For example, in the example in Figure 1, the frequency of radio waves in use is 2 waves, while in Figure 2 (a) it is 5 waves, so the probability is that the frequency is 2.5 times more susceptible to radio wave interference. . Moreover, as is clear from Fig. 2(a), any one of the five waves f I""' f a
When radio interference (interference) occurs in the waves, it has a negative impact on all construction workers, and when the FL is interfered with, all construction workers except the conductor suffer from interference, making it impossible to make calls.

As a measure to reduce this interference to some extent, the base station is provided with a spare frequency F2, and each of the portable radios 9 to 12 is provided with a spare frequency g + '------"'g.
There is a method of providing 4 spare channels, but as mentioned above, it has not been possible to provide a larger number of spare channels due to economical reasons or the size of the portable radio device. Additionally, even with such measures in place, it is cumbersome for construction workers to stop work, discover which wireless channel is experiencing radio interference, and then manually switch to a backup channel. Therefore, it was practically impossible to avoid interference.

(Objective of the Invention) The present invention forms independent communication paths between any number of portable radio devices among a large number of portable radio devices, and further eliminates radio wave interference so that there is no interference with other communication paths. This provides a wireless paging communication system that allows telephone calls.

(Structure and operation of the invention) The present invention will be explained in detail below with reference to the drawings.

Figure 2 (bl) is a layout diagram showing the basic configuration of the system of the present invention. These portable radios use Multi Channel Access J (hereinafter referred to as rMcAJ) technology, which has been recently developed and is widely used in various radio systems, especially mobile radio systems. It is possible to set a large number of channels (therefore, the number of transmission frequencies) that can be transmitted by a device, and technically it is in practical use up to about 1000 channels. While they had one to two
It will have the same function as having 1,000 pieces, so there is no need to manufacture different types of portable radios with different transmission frequencies as in the past, and manufacturing the same type of portable radios will suffice to achieve the purpose. I can do it.

Now, if we apply this MCA technology to portable radio devices and assume that each portable radio device can use 100 wireless channels, a large number of construction workers (second In the example shown in Figure (b), it is possible for eight people to make simultaneous calls to the conductor located at the base station. Here, a control channel of frequency fcI (hereinafter abbreviated as a downlink control channel) is used to transmit control signals from the base station 8 to the mobile radios 9 to 16, and from the mobile radios 9 to 16. A control channel of frequency fc2 (hereinafter abbreviated as an uplink control channel) is used to transmit a control signal to be described later to the base station 8, and signal transmission from each portable radio device 9 to 16 is as shown in FIG. They are configured to be differentiated from each other on a time-sharing basis. Here, ST is a start signal that distinguishes each frame, and the portable radio 9.10
．． 11. −−−−−−. Each of the 16 time slots Tq
, T+. +TI++-・-・-'+ T I 6 and T
q-, T+. 3°Tza+−・−・+Tl6m are sequentially allocated as shown. In the control channel, a calling signal etc. from a mobile radio station and a channel designation signal etc. from a base station are transmitted using, for example, a subcarrier MSK modulation method (mark frequency is 1,200 Hz, space frequency is 1,800 Hz).
z) at a transmission rate of 1.200 bit/s.

The base station 8 in FIG. 3 (al (b)) showing an embodiment of the present invention
The control channel controller C0NT and the transmitter T-
and receiver Rmx use these downlink control channels (rc+
) and uplink control channel Dcz), and the hybrid circuit H+ and antenna AT form a control channel transmission path for each of the portable radios 9 to 16. In the base station, a control channel controller C0NT monitors the usage status of communication channels, and if there is an empty channel for a call, it specifies that channel. The operation in this case will be explained below.

First, it is assumed that the base station is also in an operating state. When workers arrive at the construction site, they each use their own portable radio device 9-1.
6. Turn on the power. As a result, the calling signal ■ is sent to the base station via the uplink control channel fc2. The base station is
When a calling signal is detected, an ID signal sending command (■) is sent to all portable radios.

In this case, the portable radio device that receives the control channel sent from the base station receives an ID signal given to the portable radio device. is a different number unique to the individual) to the base station, and the construction worker using the portable radio is at the work site and is ready to make a call at any time if the base station specifies a call channel. to notify you of this. On the other hand, the base station decodes the ID signal from the portable radio and designates a communication channel for the corresponding portable radio.

On the other hand, the portable wireless devices 9 to 16 are in a state where they can receive downlink control signals from these base stations.

For example, when the portable radio device 9 receives the communication channel designation signal (■) given to itself from among the downlink control signals, the control circuit of the receiving section selects the communication channel assigned to it (which is different from the control channel in terms of frequency). ), the channel switch completion signal (■) indicating that the channel has been switched to the base station is transmitted to the base station on the uplink control channel by operating the transmitter of the own portable wireless device only during the time slot allowed.

If the other portable radio devices 10 to 16 perform a calling operation by turning on the power, mutual transmission of control signals similar to that of the portable radio device 9 described above can be performed using the uplink control channel (transmission frequency fcz) of the own portable radio device. , Base station download system? This is done using channel III (transmission frequency nfcl), and all portable wireless devices are ready to communicate on communication channels designated by the base station.

After the call ends, if you turn off the power on the mobile radio in question,
The end of call signal (■) is sent to the base station, and the base station also sets the communication channel of the mobile radio to "end of call" and waits for the next calling operation.

FIG. 5 is a flowchart of the operations between the base station and the portable radio device described above, and these operations are performed in parallel and independently for each portable radio device.

FIG. 2 (11) shows the communication channel allocation arrangement in this situation. That is, the portable radio 9 receives the frequency F1 of the base station communication channel, and can transmit on the communication channel 10 frequency f, and the mobile radio 9 receives the frequency F1 of the base station communication channel, and can transmit on the communication channel 10, frequency f. 20 frequency f
2, and 11 receives the frequency F of the base station communication channel, and receives the frequency 13 of the communication channel 3.
Similarly, the portable radio 16 receives the frequency F1 of the base station communication channel, and can itself transmit the frequency f8 of the communication channel 8. Now, the second
In the wireless paging communication system shown in Figure (b), each owner of a portable wireless device can talk to the construction commander at the base station whenever necessary without interference from others. .

FIG. 3(a) shows an example of the configuration of a wireless base station,
Since different communication channels (therefore, side frequencies) are assigned to the communication channels in the right portable radios 9 to 16, it is clear that communication with the base station can be performed without mutual radio wave interference. Now, at the base station, the transmitting and receiving antenna AT
The received radio waves coming in are inputted to receivers RX9+'-'+RXI6 each having a bandpass filter. here,
The portable radio device 9 corresponds to the receiver RxQ, the receiver 10 corresponds to the receiver RXIO, and the receiver RxQ corresponds to the receiver RxQ. The demodulated output (audio output) of these receivers is output from the audio mixing circuit VM.
The signals are mixed at the IX and output from the monitor speaker SP to the conductor at the base station. Further, the conductor can personally transmit instructions using the microphone old C via the transmitter TX. The hybrid circuit HI and antenna correction are shared for the control channel and voice transmission.

Since 100 wireless channels can be used with this portable radio, if the radio wave interference countermeasures described below are not required, technically 100 construction workers each own a portable radio and the base station conductor This shows that it is possible to communicate with

Next, due to the high frequency of use between radio base stations and portable radios, and due to the necessity of construction safety, workers are required to constantly listen to the instructions of the conductor, and other workers are required to conduct the conductor's instructions. The first step is to develop a system configuration when it is required to monitor the contents of calls with employees and use them as reference for their work, and to enable calls between three or more parties involving individual workers at any time when necessary. This is shown in Figure 3 (b). The difference between this figure and FIG. 3(a) is in the output of the audio mixing circuit VMIX in the receiving section of the base station.
Part of the output is added to the output of the base station monitor speaker SP, and the other part is mixed with the output of the base station worker's microphone MIC by the hybrid circuit H2, added to the transmitter T8, and transmitted to each portable radio device. be done. By receiving the radio waves transmitted by the base station, each portable radio device can listen in on calls not only from the conductor but also from other construction workers. Technically speaking, it can be seen that in this example, a maximum of 101 people can talk at the same time.

Furthermore, if the base station configuration shown in Figure 3 Tb) is applied, the construction leader does not necessarily need to be at the base station, and the base station is stationed only for monitors or is unmanned, and can be used at construction sites where other construction workers are present. It is clear from this diagram that even if you are nearby and take direct command, it is possible to carry out exactly the same communication as described above.

Now, we will explain countermeasures when radio wave interference, which is a difficult problem to solve in conventional systems, occurs in the system shown in FIG. 3 (al or (bl).

As an example, if an interference radio wave frequency close to the transmission frequency f1 of the portable radio device 9 occurs, the contents of the call by the owner of the portable radio device 9 cannot be received by the construction leader 8. This state is discovered by the interference detector DT in the radio base station configuration diagram shown in FIG. 3(a). That is, this interference detector DT has radio frequencies F,, F2 . −・.

fl+ f2+-'-'+ f8+ gl+ gZ+'
-1・ga+ hl, h2. This is a well-known device that has the M1 function of patrolling H8, etc., switching and receiving signals, and detecting the presence or absence of interference. However, F,, F,, -・- are the base station transmission frequencies, rl, fz, -, fe, g+-gz,
'-'gelh+, hz, ...hIl-, etc. are predetermined as the transmitting frequencies of the mobile station.Now, when this interference detector DT detects that the frequency is being interfered with, this information is transmitted. Base station control channel controller C
0NT, and CP[ in the control channel controller C0NT
For example, by operating J, select the communication channel f of the portable radio device 9.
, when there is interference in the downlink control channel time slot T to the mobile radio 9, a new call CH designation signal ■ is sent to the mobile radio 9 to switch the carrier frequency of the call signal from fl to g+. Directed by. When the channel switching is completed, the portable radio device 9 sends a new call CH switching completion signal (2) to the base station 8 via the uplink control channel fc2. At the same time, the receiving frequency of the receiver Rx9 of the base station is changed from fl to g, and the receiver Rx9 shifts to the receiving state. Similarly, all other portable radios (1
The corresponding downlink control channel timeslots (T, .~Tea)!
At the same time, the base station receiver (RXto~
RX16) reception frequency from f2~flI to g2~g8
change it to Although the interference detector DT has already detected that there is no interference in these new frequency groups, it should be checked again just before the frequency switching instruction, and if interference has occurred, it will be detected. Allocate another frequency group h1゜hz, -・-ri, which has not been received yet. The above frequency switching operation is shown in the flowchart of FIG. By replacing this step with the call (V) step in the flowchart of FIG. 5, the entire operation proceeds from call origination to end of call.

The above explanation deals with the case where interference radio waves close to the transmission frequency f of the portable radio device 9 occur, but the same applies when interference occurs with other portable radio devices or multiple portable radio devices, etc. be.

Next, when radio wave interference occurs near the transmission frequency F1 of the wireless base station, it is detected by the interference detector DT and a base station transmission frequency change command signal is sent from the control channel controller C0NT to the base station transmitter Tax. The transmission frequency is F,
to F2. At the same time, the reception frequency is changed from Fl to F2 for each portable radio through the downlink control channel.
to change the receiving frequency.

A number change command signal is sent. Each portable wireless device that receives this control signal changes its reception frequency from Fl to F2.

Thus, each call can continue using the interference-free new circular wavenumber group.

Note that the above-mentioned control signal may be transmitted by temporarily cutting off the call signal and transmitting it during that time, or by using an upper or lower side band of the voice signal band and transmitting it without affecting the voice signal in any way.

As mentioned above, it is necessary to provide spare channels to prevent interference, but if the MCA technology described above is used, mobile radio equipment can have significantly more channels than the conventional manual switching method based on crystals. I can do it.

For example, in the embodiment of the present invention shown in FIG. 2, there are 12 groups (96 waves ÷
8 waves, however, the remaining 4 waves out of 100 waves are for the control channel. ) can be prepared, and the risk of interference is actually greatly reduced. It is clear that this effect would be further reduced if MCA technology were used to allow portable radios access to a larger number of radio channels.

Finally, one example of the interference detector DT used in the embodiment of FIG. 3(a) or (b) will be explained. first,
At the stage when a communication path is established between the base station and the mobile radio, this receiver detects interference waves by unmodulating the desired signal (S) and detecting interference from noise (N) that falls within the voice band. A method is adopted in which the level (N+1) of the noise (I) is determined and it is confirmed from this whether the required S/N +1 is satisfied. The principle and circuit for detecting interference during a call are shown in FIGS. 6(a) and 6(b). In other words, the desired wave (D wave) and interference wave (U wave) caused by interference
The presence or absence of interference is determined by performing AM detection on the beat component of the wave) and determining its level.

In implementing the system of the present invention, a microprocessor or the like may be used to implement control in software, thereby realizing various functions necessary for multi-channel access.

FIG. 8 is a block diagram of the configuration of the mobile device, particularly showing in detail an example of the configuration of the frequency synthesizer. The configuration of the frequency synthesizer 30 shown in the figure is said to be a phase-locked loop (PLL). In the figure, the output of the voltage controlled oscillator 31 is applied to the transmission mixer, but a part of its output is also applied to the programmable divider 33, and is again input to the voltage controlled oscillator 31 by the loop circuit output described below, and its oscillation frequency is By changing the frequency, the input frequency to the transmission mixer changes, and it becomes possible for the base station control unit to transmit radio waves having a desired frequency from the mobile radio.

That is, the output of voltage controlled oscillator 31 is applied to programmable divider 33. Here, the voltage controlled oscillator 3
The output of 1 is stepped down to a frequency division ratio (1/N), and this frequency division number N is determined by the channel selection switch 32. In addition, the output of the programmable divider 33 is made the same as the output frequency of the crystal oscillator 34, and when these three frequencies are applied to the phase detector 35 and passed through the low-pass filter 36, a DC output voltage corresponding to the phase difference between the two inputs is generated. can get. By applying this voltage to the voltage controlled oscillator 31, the oscillation frequency of the voltage controlled oscillator 31 is controlled.

The above is an outline of the operation of the PLL, and the oscillation frequency of this PLL is configured so that it can be easily set to any frequency by the channel selection switch 32. Now, a signal for operating the channel selection switch 32 is output from the transmission/reception frequency control section 40. The C11 switching control signal sent from the base station is decoded by the control section 40, and a designated channel is selected according to the base station command.

The number of selectable channels is generally in the hundreds.

The above explanation relates to an example of the structure of a portable wireless device, but for determining the frequency of the transmitting/receiving section of a base station, a circuit having a hardware configuration similar to that in FIG. 8 is used in the configuration shown in FIGS. The transition to the new wave number will be implemented in the same way as portable radio equipment.

(Effects of the Invention) By using the present invention as a substitute for the conventional radio paging system, it is possible to prevent communication from occurring due to interference when a large number of workers start talking at the same time due to the limited number of channels owned by mobile radio devices. This problem has been eliminated through control that includes batch switching of used frequency groups, and at the same time, the hassle of manually switching radio channels has been eliminated, greatly improving construction efficiency and safety. It is clear that a contribution can be made.

In addition, compared to manufacturing many types of portable wireless devices with different transmission frequencies as in the past, the present invention allows MCA
The ability to easily configure a system by manufacturing the same type of portable radio using technology has great effects in terms of mass production effects, such as reducing the number of man-hours and the types of parts used.

[Brief explanation of the drawing]

1 and 2 (al is a layout diagram showing an example of a conventional wireless paging system, FIG. 2 (bl is a layout diagram showing an example of a wireless paging system according to the present invention, and FIG. 3(a)
(bl is a block diagram showing a configuration example of a wireless base station used in the present invention, FIG. 4 is a time chart showing an example of transmission of control signals between a wireless base station and a portable radio device in the present invention,
7 and 7 are flowcharts for explaining the operation of the system of the present invention, FIGS. 6(a) and (b) are waveform diagrams for explaining the principle of interference detection used in the present invention, and FIG. 1 is a block diagram showing an example of the structure of a frequency synthesizer used in the present invention. FIG. ■... Wireless base station, 2.3.4.5.6.7...
Portable radio, 8...Multi-channel access radio base station, 9.10.11.12.13.14.15
．． 16...Portable radio. Missing 3 fD (0) 〒3 indentation (bl voice 4 figure door 6 [Procedural amendment (method)) 7 November 18, 1985 Mr. Michibe Uga, Commissioner of the Patent Office (1
11. Indication of the case Patent application No. 1155936 No. 2, Title of the invention Single tooth wireless paging system 3, Person making the amendment Relationship to the case Applicant (042) Iwasaki Tsushinki Co., Ltd. 4, Agent Shinjuku, Tokyo 1-23-1 Nishi-Shinjuku, Ward 5. Date of amendment order: October 29, 1985 (sent) 6. "Detailed explanation of the invention" column of the specification to be amended and the statement of contents of the amendment. The description is corrected as follows: Page 19, line 19 is corrected as follows: [The principle of interference detection inside is shown in Figure 6] Page 23, line 1
From line 0 to line 11 [Figure 6 fa) (b)]
Figure] is corrected.

Claims (1)

[Claims] A large number of mobile radios are arranged so that they can connect simultaneously to a radio base station using multi-channel access technology,
Control by the multi-channel access technology in the radio base station is configured to form independent communication paths between at least two of the plurality of portable radios, and among the independent communication paths, When at least one of the communication channels in use becomes unavailable due to radio wave interference, it is confirmed that all the radio wave frequencies used between the plurality of portable wireless devices and the base station are predetermined and that there is no interference. A wireless paging communication system configured to switch to another frequency group in which a call has been made and to recover the call that has become impossible.