JPH0116062B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for wireless communication, in particular, a channel selected from a plurality of radio frequency channels.
The present invention relates to an improved apparatus and method for establishing communications between a first transceiver and a second transceiver through a repeater.

In many regions, multiple terrestrial mobile radio frequency channels are allocated for communication between vehicles. In general, there can be, and usually is, more vehicles with radio transceivers than there are radio frequency channels available in a given region.
Therefore, some way of making radio frequency channels available to users of mobile vehicles is needed.
In this specification, a radio frequency channel refers to at least a first radio frequency for transmission and a second radio frequency for reception.

The invention detects an empty radio frequency channel among a plurality of radio frequency channels;
A new and improved apparatus and method for operating a transceiver on its free channel to communicate with another transceiver is provided.

The invention also relates to a new and improved apparatus or method for establishing wireless communications between vehicles via a wireless repeater.

The invention further provides a new and improved apparatus or method for detecting a vacant radio frequency channel and operating a transceiver on the vacant channel for communicating with another transceiver via an intermediate repeater. Also provided.

Another feature of the invention is to provide a call origination mode in which the call is made so that the associated radio transceiver operates on a free radio frequency channel and other transceivers in the selected or scheduled group operate on the same radio frequency channel. It is an object of the present invention to provide a new and improved communication setup scheme that can operate on radio frequency channels.

Further, the present invention provides an "idle" or call waiting mode in which calls can be received;
A new and improved communications configuration that allows an associated radio receiver to scan or search for available radio frequency channels and to operate an associated radio transceiver on a radio frequency channel having a tone representative of a scheduled group. provide a method.

A method is provided for setting up wireless communications between vehicles. This is sometimes called a relay method.
However, this system is relatively complex and therefore expensive or requires separate radio signal channels to establish communications between vehicles. Such signal channels are typically not available for voice communications, so that the utilization of the radio frequency spectrum is not as efficient as desired.

It is therefore an object of the invention to provide a new and improved method of setting up wireless communications between vehicles that is relatively simple and therefore inexpensive.

Another object of the invention is to provide a new and improved scheme or method for setting up wireless communications between vehicles via repeaters without the need for separate wireless signal channels.

The present invention provides a new and improved mobile radio relay system that operates without a common control terminal at or in conjunction with a repeater, as required by some prior art relay systems. .

Briefly, the above and other features and objects are achieved by the scheme of the present invention for each radio transceiver belonging to a communication device.

The method described here can be used as either a call origination format or a call waiting format depending on the user. In the call origination mode, the system of the present invention causes the receiver to scan all assigned radio frequency channels of the system until a free channel is found. When a free channel is found, the method enables the transceiver to operate on that channel, then causes the transmitter to transmit a busy tone, contacts a repeater on that channel, and activates the repeater. , then causes the transmitter to transmit the scheduled group tone(s) associated with the particular scheme. The repeater transmits a busy tone on its channel and retransmits the group tone. For each other radio transceiver in a call waiting mode, the method of the present invention continuously scans all radio frequency channels assigned to the receiver to detect its scheduled group tone(s). ). When a receiver detects its intended group tone(s) on a channel, the system stops scanning the receiver and communicates via the repeater with the transceiver in the calling mode. Therefore, operate this transceiver on that channel. Scheduled group signal tone(s)
A plurality of such transceivers can be associated with each other. Thus, a new and improved scheme or method for setting up wireless communications between vehicles via repeaters is provided.

The structure, operation, and other objects and advantages of the present invention will be better understood from the following description of the drawings.

By looking at FIG. 1, the necessity and use of the system or method of this invention will be better understood. 1st
The figure assumes that a given region is assigned five radio repeater communication channels (e.g., a frequency band centered at 850 MHz), each channel having a different radio transmit frequency and a different radio receive frequency. . For 5 channels, 5
Two repeaters R1 to R5 are provided, located at convenient locations to provide the best radio frequency coverage. Each repeater R1-R5 includes a transmitter, a receiver, a transmit antenna, and a receive antenna. In simplex operation, at the first repeater R1, the receiver and the receiving antenna operate at the frequency F1-R, and the transmitter and the transmitting antenna operate at the frequency F1-T. Frequency F1-T is separated from frequency F1-R by an amount that provides good frequency separation for the transceiver. For repeaters R2 to R5, other frequencies F2-R and F2-T to F5-R and F5-T are used. Different groups of users in the same locality can use these repeaters, for example by means of radio transceivers installed in their mobile vehicles V1 to V5. Typically, each group consists of vehicles engaged in a given business;
For example, there are common standards such as taxis and a group of oil trucks. The number of groups that a repeater can serve depends on, inter alia, the number of vehicles in a group, the length of time the radio channel is used, and the number of available repeater channels. for example,
Five repeaters (each with a transceiver operating on a different frequency than the other repeaters) can serve 2000 vehicles. However, the number of vehicles that can be effectively addressed can vary depending on the demands of the channel.

When multiple relay channels are available in a given region, it is possible for a group of vehicles to quickly determine which channels or frequencies are available to establish communications with other vehicles in the same group. desirable. The present invention provides a relatively simple but reliable way to set up this communication.

A block diagram of the invention suitable for use in a mobile station, such as that installed in a vehicle, is shown in FIG.
In FIG. 2, the case of vehicles in the group of vehicles V1 to V5 shown in FIG. 1 is assumed. A radio transmitter with which the vehicle station can operate on any frequency F1-R to F5-R and any frequency F1-T to F5.
- has a radio receiver 12 capable of operating at T. Two frequencies are required for each channel so that the vehicle and repeater can function in a simplex, or pre-talk, manner. That is, this vehicle transmits at the repeater reception frequency (for example, F1-R). This frequency F1-R is received by the repeater and frequency R1-R is received by the repeater.
- T to be sent to other vehicles. Other vehicles in the group receive this repeater frequency F1-T. When transmitting, other vehicles transmit on frequency F1-R. In this method, one antenna 10 is connected to a relay 1 depending on whether a vehicle, that is, a mobile station is transmitting or receiving.
9 switches between transmitter 11 and receiver 12 of a vehicle or mobile station. For full duplex communication, each repeater requires four frequencies for each channel. Transmitter 11 and receiver 1
2 is assumed to be a frequency modulation device, but it may also be an amplitude modulation device. Transmitter 11 includes an oscillator circuit that operates at one of five frequencies in response to a signal applied from search generator 13 . The receiver 12 is preferably of the superheterodyne type and its local oscillator also operates at one of five frequencies depending on the signal provided by the search generator 13. Generator 1 at a fast or slow speed determined by control circuit 15.
A clock signal is generated by 6. This clock signal is supplied to the search generator 13, and the generator 1
3 sequentially generates a frequency scanning signal on each of the five outputs shown in FIG. This scanning signal is applied to the transmitter and receiver oscillators, enabling transmitter 11 to operate sequentially at radio frequencies F1-R through F2-R and receiver 12 at radio frequencies F1-T through F2-R. Make it possible to operate sequentially with F5-T. A tone encoder, a decoder, and a gate are used to decode or encode the tone received by the receiver 12 and to generate a tone that is encoded or gated and transmitted from the transmitter 11. A device 18 is provided. In order for the operator or user to operate their own station and obtain an indication of the operation of their own station,
The mobile station has an operator control and display 14. The operator control unit allows the operator to set up communications with other vehicles in the same fleet by placing the transceiver in the "calling" mode, or by placing the transceiver in the "calling" mode and establishing communications with other vehicles in the same group. Enable to receive communications from other mobile stations.

A control circuit 15 provides a clock signal from a clock generator 16 to a sequence generator 17 when the operator control places the station in the call originating mode, and provides a clock signal from the clock generator 16 when the operator control places the station in the call waiting mode. The signal is fed to a "search" generator 13.

In the call mode, the control circuit 15 clocks
The pulses are applied to a sequence generator 17 which generates a signal having a sequence of action as described below. That is, first, locating an empty channel; second, contacting the repeater by transmitting an audible busy tone to the repeater; and enabling or activating the repeater's transceiver on the empty channel; Second, transmit an audible group signal tone (with a selected frequency), which is relayed, or retransmitted, by a repeater to signal all other stations in the same group, and fourth. transmitting an audible subgroup tone (with a selected frequency) if the stations within a given group are further divided into smaller groups;
Fifth, stop transmitting and have the mobile station's receiver listen to see if the repeater is transmitting busy tone on this selected channel; Sixth, the repeater transmits If the machine is not enabled in the second action, the sequence is repeated. If a repeater transmitter is activated, the operator shall be given an indication that his station has contacted and activated the repeater and that his station and repeater are ready for operation. It will be done.

In the call standby mode, the control circuit 15 clocks
By supplying the pulse to the search generator 13, the generator 13
generates a signal to change the frequency of the oscillator of the transmitter and receiver. This causes receiver 12 to sequentially tune to each of the five frequencies that the repeater may transmit, while transmitter 11 sequentially tunes to each of the five associated frequencies that the repeater may receive. Synchronize. If no suitable signal or tone is detected at a certain frequency, the generator 13 quickly tunes the transmitter and receiver to the next channel frequency.
This sequence continues as long as the receiver 12 is operational, and only when the receiver 12 receives the busy tone, the scheduled group signal, and its subgroup signal (if used). stop. When the group tone and subgroup tone (if used) are received, control circuit 15 issues an indication to the operator that the station is being called. The operator can now pick up the handset or microphone and communicate with the calling station.

FIG. 3 is a block diagram of one repeater shown in FIG. 1 used in the control system of the present invention. In this repeater, an antenna 30 is connected to a receiver 31 and receives a specific frequency, for example F1-R.
The output of the receiver is connected to a busy tone notch waver 32 which blocks or eliminates the busy tone but applies the received audible signal, group tone and subgroup tone to a transmitter 33. A transmitter 33 is connected to an antenna 37 and transmits a frequency F corresponding to this channel.
Transmit with 1-T. The paired frequencies F1-R and F1-T of this channel are far enough apart to allow proper circuit operation. Receiver 31 and transmitter 3
The same antenna can be used for all three repeaters, or all repeaters can be operated with the same antenna. The output of the receiver is applied to a busy tone waveband detector and detector 34 which detects only busy tone frequencies and applies a busy tone detection signal to a timer 35. A timer 35 generates an activation or keying signal at the beginning of the busy tone, as long as the busy tone is detected, and for a selected period of time (e.g., 10 seconds) after the end of the busy tone. do. This activation or keying signal turns on or activates the transmitter 33. When the activation signal ends, the transmitter 33 automatically turns off without any signal tone. This feature prevents the repeater transmitter 33 from being accidentally keyed or activated when a proper busy tone signal is not present. Timer 35 allows the repeater to be made available to another group if the group to be contacted does not transmit that frequently, for example every 10 seconds. The repeater includes a busy tone generator 36 which transmits the busy tone to the transmitter 3 along with an audible tone, a group tone and a small group tone.
Sent to 3. To ensure that the mobile station remains operational even if there is a temporary absence of transmission from either mobile station (e.g. for a few seconds less than 10 seconds), the busy tone is replayed at the repeater. preferably occurs. However, the group tones and subgroup tones are sent from the mobile station's transmitter through the repeater's transceiver. The individual blocks of FIG. 3 are well known and therefore there is no need to explain them in detail. 1st
Each repeater in the figure is similar to FIG. 3, but operates at a different frequency.

FIGS. 4A to 4D show detailed circuit diagrams of the mobile station communication setting method shown in FIG. 2. When Figures 4A to 4D are assembled as shown in Figure 5 and the circuit conductors at the corresponding positions (at the edges of the drawings) are connected, they constitute one drawing as Figure 4. be. For clarity, the transmitter 11 in FIG.
Receiver 12 and antenna 10 are omitted. In FIG. 4, a search generator 13, a clock generator 16,
The signal tone encoder, decoder and gating device 18, operator control and display device 14, and sequence generator 17 are each shown within the dashed box. The other parts of the circuit outside these boxes constitute the control circuit 15. The circuit in Figure 4 uses four types of logic gates: an OR gate as shown in G1, a NOR gate as shown in G2, an AND gate as shown in G3, and an inverter as shown in I1. . As is known, an OR gate produces a logic 1 at its output when any of its inputs is a logic 1, and produces a logic 0 at its output when all inputs are logic 0. A NOR gate produces a logic 0 when any input is a logic 1, and a logic 1 when all inputs are a logic 0. An AND gate produces a logic 0 when any input is a logic 0, and a logic 1 when all inputs are a logic 1. An inverter simply logically inverts the signal applied to its input. In the circuit of this invention, a logic 1 is a positive voltage +V, and a logic 0 is a positive voltage +V.
Assume bolt or ground level. However, logic 1
Other voltages may also be used for logic zeros.

The circuit uses a number of bistable flip-flops, such as flip-flop FF1. flip flop
FF1 applies a logic 1 to its Q output in response to a temporary logic 1 applied to its set input S.
It produces a logic 0 at its output and, in response to a logic 1 momentarily applied to its reset input R, produces a logic 0 at its Q output and a logic 1 at its output. Additionally, the circuit uses timer T1 (Figure 4A), which is normally reset and produces a logic 1 at its output. When timer T1 is set by applying a logic 1 to its set input, it will run for a predetermined period of time (approximately 10 seconds in the preferred embodiment).
generates a logic 0 at its output for a period of time (seconds). When this scheduled time expires, timer T1 is reset and the output therefore produces a logic one. This scheduled time can be adjusted by a resistor circuit attached to timer T1. A timer T2 is also provided.
This timer is similar to timer T1, but in the preferred embodiment, its timeout period is approximately 15 seconds. Additionally, timer T2 has an inhibit input INH. Timer T2 is set and input is prohibited.
When a logic 1 is applied to INH, timer T2 continues to generate a logic 0 at its output as long as the logic 1 at the inhibit input is applied. When the logic 1 on the inhibit input disappears, timer T2 is reset and its output returns to logic 1.

Clock generator 16 (Figure 4D) includes a pulse oscillator that is responsive to a logic 1 applied to the speed control input SC, as well as a logic 0 applied to the input SC, at a high rate (approximately every 30 milliseconds). is applied at a slow rate (approximately every 60 milliseconds) to generate a logic 1 pulse of approximately 10 milliseconds in duration. These pulses are generated at the Q output.

Sequence generator 17 (FIG. 4B) has a six stage shift register SR1 having a clock input C, a reset input R, and a feedback input D. shift·
When register SR1 is in its initial or reset state, stage 1 is at logic 1 and all other stages are at logic 0. This logic 1 is sent sequentially to subsequent stages 2-6 in response to a clock signal. Each stage may include a number of substages depending on the timing effects required for a given stage. In the preferred embodiment, tier 1 has one tier, tier 2 has two tiers, tier 3 has 6 tiers in a 5-channel system, tier 4 has 2 tiers, and tier 5 has 5 tiers. It has small steps, and step 6 has one small step. Now there are 17 steps in total, and if the clock pulses at a rate of every 60 milliseconds, then the shift register
It takes approximately 1.02 seconds to pass through SR1 once.
Stage 3 is preferably of long duration so that each receiver in the group has sufficient time to scan all channels looking for the group tone, if any. Stage 5 preferably has a duration long enough to determine that the repeater has been activated.
These times will be explained in more detail later. logic 1
When it reaches stage 6, it is fed back to the feedback input D and then passes through each stage. count 2 counter 6
0 is connected to stage 6 to produce a logic 1 at its output in response to every other logic 1 in stage 6. In the search generator 13 (Fig. 4D), 5
A five-stage shift register is provided for each channel frequency. Each stage has only one small stage. A logic 1 is passed from one stage to the next stage in response to a clock pulse at clock input C. When a logic 1 reaches stage 5, the next clock pulse feeds it back to the feedback input D, shifting each stage thereafter.

Signal tone encoder, decoder and gating device 18
(FIG. 4C) there are four tone encoding-decoding circuits TC1 to TC4. Each of these circuits includes a decoder portion with a tone input T connected to the audible output of the receiver 12. The decoder section includes a wave generator that generates a logic one at its Q output in response to a tone of a predetermined frequency. Although the Q outputs of circuits TC3 and TC4 are shown applied to OR gate G11, these Q outputs could also be switched to be selected individually by other portions of switch 46. Each circuit also includes an encoder portion that generates a particular tone frequency depending on the intended effect of the tone. A relatively high audible frequency of 3000 hertz is preferred as the busy tone. This is because higher frequencies pass through the transducer and it operates more quickly. The group tones and subgroup tones may be at any suitable frequency, but are preferably within the audio range of the transmitted audio frequencies, ie, from 400 to 3000 hertz. Each circuit TC1-TC4 acts as an encoder in response to a logic 1 applied to its control input C and as a decoder in response to a logic 0 applied to its logic input C. circuit
The outputs of the encoder sections of TC1 to TC4 are selectively applied to a tone amplifier 51 via switches S4 to S7. The output of this amplifier 51 is connected to the transmitter 11, which modulates the transmitted signal according to the signal tone. The tone encoder, decoder and gate 18 also includes a tone burst generator 50, which
In conjunction with the ready light 41, it provides a short audible indication to the operator that the operator has received a call or that the operator has activated a repeater to transmit.

The circuit consists of a plurality of switches S1 to S, as represented by the switch arms shown in the rectangular box.
7 (Figures 4A and 4C) is also used. Since the circuit operates on logic signals, switches S1 to S7
must be fast. For this reason, devices such as FET transistors are preferred. Each switch S1-S7 is responsive to a logic signal applied to a conductor shown in phantom that contacts the switch arm. Each switch responds to a logic 0 to open its switch path and responds to a logic 1 to close the path.

The operator control 14 (FIG. 4A) includes a "wait light" 40 that indicates to the operator that the control is searching for a channel, and a "wait light" 40 that indicates to the operator that the control has enabled the transceiver to operate. a "ready" light 41 for signaling to the receiver, a microphone 42 for transmitting audio signals, a microphone press-talk button 43 for keying or energizing the transmitter to transmit, and a speaker 44 for listening to the received audible signals. and microphone 4
a microphone switch 45 which has the end position when the microphone 2 is placed on the switch 45 and a response position when the microphone 42 is removed from the switch 45; and a small group selection switch 46 when using the small group signal tone.
There is. A notch waveform F1 (FIG. 4A) is connected between the receiver's audio output and the speaker switch S2 to filter out busy tone (preferably 3000 hertz). Otherwise, the operator will hear this busy tone. If desired, the microphone 42 and speaker 44 may be connected to the switch 4.
It can be replaced with other devices, such as a telephone handset that can make a 5.5 call.

When an operator is at the mobile unit and expects to be called at any time, the operator puts the mobile station's equipment into a "call-ready" mode by turning on its transceiver. Power is then applied to the device and the voltage +V is passed through the termination contact of switch 45 and capacitor C5 as a logic 1.
Flip-flop if not already reset
While resetting FF1 and FF3, it is applied via capacitor C1 and OR gate G16,
If it has not already been reset, flip-flop FF2 is reset. However, the transmitter is keyed, ie, not transmitting, and the mobile station's antenna is connected to the receiver. If conditions require differentiation of mobile stations within a group, subgroup tones (one for each desired subgroup) can be used. In FIG. 4, it is assumed that two subgroups are utilized, and the stations shown are in subgroup 1. Therefore, a small group selection switch 46 (FIG. 4A) is connected to the small group contact 1. This connects the signal tone circuit TC3 (Figure 4B) of small group 1 to the circuit, and
The signal tone circuit TC4 (FIG. 4B) is disconnected from the circuit. In the receive mode, the output of reset flip-flop FF1 (FIG. 4A) is a logic 1;
Its Q output is a logic zero. flip flop
FF3 (Figure 4B) is also reset and its Q output is a logic zero. This causes AND gate G18 to generate a logic 0 and the clock pulse to the shift register in sequence generator 17 (Figure 4B).
Make sure that no voltage is applied to SR1. The logic 1 generated by the output to flip-flop FF1 is
It is inverted to logic 0 by inverter I1 (FIG. 4C). This logic 0 generates a logic 0 from AND gate G8 (Figure 4D). If no signal is present, the sensing device connected within the receiving circuit is at logic zero. The sensing device can detect carrier signals or busy or group tones, as desired. Preferably, the sensing device detects a busy tone frequency. A logic 0 (no signal) is converted to a logic 1 by inverter I2 (Figure 4D) and applied to AND gate G9 (Figure 4D) along with a logic 1 from the output of flip-flop FF1. AND gate G9 generates a logic 1;
This generates a logic 1 from OR gate G10 so that the speed control input SC is connected to clock generator 16.
pulses at a rapid rate (e.g. every 30 ms). The logic 0 generated by inverter I1 (Figure 4C) causes signal tone circuits TC2, TC
3. TC4 performs decoding function. Or Gate G2
The output of signal tone circuit TC1 (FIG. 4C) is a logic 0, so that the signal tone circuit TC1 (FIG. 4C) also has a decoding function.
However, if the signal tone is not received at this time, the decoder
The Q outputs of TC1, TC2, TC3, and TC4 are logic zero. Therefore, gate G5 (FIG. 4D) is at logic 0.
occurs. Flip-flop FF2 (Figure 4A)
has also been reset, so its Q output is a logic 0 and its output is a logic 1. In this state, all inputs to NOR gate G2 (Figure 4D) are logic 0, so gate G2
generates a logic 1. This logic 1 causes AND gate G6 to pass the logic 1 clock pulse generated by generator 16 (this time at a fast rate). These clock pulses pass through AND gate G6 and OR gate G7 to shift register SR2 of search generator 13.
input to clock input C. This causes logic 1's to be sent to stages 1 through 5 sequentially. As this logic 1 passes through each stage, it changes the oscillator frequency of the mobile station's transceiver, so that the transmitter and receiver sequentially switch to frequencies F1R, F1T, F2R and F2T, F3R and F3T, F4R and F4T. , F5R and F5T.

When a signal is detected on a certain channel of the receiver,
A signal sensing device generates a logic one. Since this logic 1 is inverted to logic 0 by inverter I2 (Figure 4B), AND gate G9 (Figure 4D)
generates a logic zero. At this time, or gate G1
Since both inputs to 0 are logic 0, the generator 16 switches to a slow pulse rate (e.g. every 60 milliseconds) and the receiver circuitry outputs the busy tone, group tone and small group 1 tone. It gives you enough time to detect (if you use it). If a busy tone is present, the busy tone decoder TC1 (Figure 4C) outputs a logic 1 at the Q output.
occurs. If a proper group tone is also detected, group tone detector TC2 generates a logic 1 at its Q output. This logic 1 is held long enough by capacitor C4 to detect the subgroup 1 tone. When a busy tone and a group signal tone are received, the signal tone detectors TC1 and TC2 output a logic 1 on their Q outputs.
occurs. For this reason, AND gate G5 (4th
(Figure D) generates a logic 1 and NOR gate G2 generates a logic 0. Because of this logic 0, the clock pulse does not pass through AND gate G6, so
The search generator 13 maintains a logic 1 in the stage of the shift register SR2 which activated the receiver oscillator (as well as the transmitter oscillator) associated with the channel frequency at which the busy tone and group tone were detected. dripping
If a proper subgroup 1 tone is detected, tone decoder TC3 (FIG. 4C) generates a logic 1 at the Q output. This logic 1 passes through OR gate G11. When decoders TC1, TC2, and TC3 simultaneously generate logic 1, AND gate G12 generates logic 1.
is generated, and this is OR gate G13 (4th A
FF2 is set, and timer T2 is set and started. When flip-flop FF2 is set,
Its Q output provides a logic 1 which causes NOR gate G2 (Figure 4D) to subsequently generate a logic 0, which blocks the clock pulse in AND gate G6. . flip flop
Logic 1 from Q output of FF2 connects three switches S
1, S2, and S3 (Figure 4A) are closed. When switch S1 is closed, microphone 42 is connected to the transmitter, and when switch S2 is closed, speaker 44 is connected.
is connected to the receiver's audible output via waveform F1 and when switch S3 is closed, the pre-talk button 43 is connected to OR gate G14 (FIG. 4B) to key the transmitter. A logic 1 from the Q output of flip-flop FF2 also turns on the ready light 41 (Figure 4A) and energizes the tone burst generator 50 (Figure 4C) (connected to speaker 44). , informs the operator that the operator is receiving a call. The mobile station's transmitter and receiver are tuned to the proper transmit and receive frequencies to communicate via the repeater with other mobile stations in the group.

The operator selects the microphone 42 (4th A).
(Fig.) from the hook switch 45,
If the operator responds immediately (within the preferred 15 second timing period of timer T2) or if microphone 42 has already been disconnected, switch 45 applies a positive voltage, or logic 1, to the response contact. A logic 1 from the response contact inhibits resetting timer T2, thus keeping the output at a logic 0. Therefore, flip-flop FF2 remains in the set state. When the operator wishes to speak, he presses the press talk button 43 on his microphone. This causes a logic 1 to be sent through closed switch S3 to OR gate G14 (FIG. 4B), keying the transmitter, causing it to transmit, and switching the antenna relay to the transmitter position. Each time button 43 is pressed, a logic one is applied to OR gate G22 (FIG. 4B), causing a busy tone to be transmitted and keeping repeater timer 35 (FIG. 3) generating an activation signal. . Releasing the pre-talk button 43 deactivates the transmitter keying and switches the antenna relay to the receive position so that the operator can hear the signal from the speaker 44. If the operator does not remove microphone 42 before timer T2 expires,
The Q output returns to logic 1, which resets flip-flop FF2. For this reason, Noah
Gate G2 (FIG. 4D) generates a logic one, which enables gate G7 to pass a clock pulse to search generator 13. For this reason,
The operator's receiver scans back to the call waiting mode and after flip-flop FF2 has been reset,
I can't hear messages. If you want to keep your channel open even if the user doesn't respond,
Simply open switch S10 (Figure 4A) and
By removing the output to gate G16, timer T2 can be omitted, thus removing timekeeping from the circuit. In this case, the user remains on this channel as long as he or she continues to operate. When the transmission is finished, the Q output of busy tone decoder TC1 becomes logic 0. This causes capacitor C6 to discharge to a logic 0, which causes inverter I4 to generate a logic 1, which passes through OR gate G16 and resets flip-flop FF2 for scanning.

When the operator has finished communicating, the operator places the microphone 42 on the switch 45.
This causes a positive voltage, or logic 1, to be applied to the clear contact. This logic 1 temporarily causes capacitor C1
and is applied through OR gate G16 to reset flip-flop FF2. When flip-flop FF2 is reset, its Q output returns to logic zero. A logic 1 from the clear contact also momentarily passes through capacitor C5 and OR gate G1, resetting flip-flops FF1 and FF3 if they have not been reset previously. When the signal tone disappears, gate G5 (Figure 4D) becomes logic 0.
occurs. Flip-flop FF3 (Figure 4B)
is still reset and produces a logic zero.
Therefore, the NOR gate G2 (Figure 4D) is logic 1.
, thereby passing a clock pulse to gate G6 and allowing search generator 13 to begin the search operation again. This search is fast because both inputs to AND gate G9 are logic ones.

To briefly summarize, when the device is in call waiting mode, shift register SR2 (Figure 4D)
Scan at high speed until the carrier is detected. When a carrier is detected, scanning switches to a slower mode. Once the busy tone and the appropriate group and subgroup signals are received, scanning is stopped and an indication is issued to notify the user of the call. Users are given a scheduled time (15 seconds) to respond (pick up the microphone).
and communicate. If the user does not respond, scanning will resume after the scheduled time.

The call origination mode also assumes that the mobile station is using the group tone and the subgroup 1 tone, and further assumes that the subgroup 1 tone causes the small group selection switch 46 (FIG. 4A) to switch to contact 1. Signal tone circuit TC
3 (FIG. 4C) is selected by connecting the circuit. Search generator 13 (4th D
) scans the channel in a fast manner since both inputs to AND gate G9 are logic 1. The operator can initiate the "call origination" mode by momentarily pressing the press talk button 43 (FIG. 4A) or by removing the microphone 42 from the hook switch 45. In either case, a positive voltage, ie, a logic 1, is momentarily applied to OR gate G17 via capacitors C2 and C3, respectively. This logic 1
is applied to AND gate G3 along with a logic one from the output of reset flip-flop FF2. AND gate G3 generates a logic 1;
This sets flip-flop FF1 and puts it into call origination mode. flipflop FF1
until the Q output of switches to logic 1, which turns on the standby light 40 and sets the channel.
Inform the operator that you have to wait. This logic 1 at the Q output is also applied to the set input S of timer T1, so that its output produces a logic 0 for a predetermined time. The scheduled time is slightly longer than 10 seconds, or the sequence generator 17 (4th B)
) is at least 2 for each channel.
It is preferable to allow enough time to go through the entire sequence twice. (If proper communication is not set up even after going through this entire sequence twice,
Timer T1 is reset so that its output generates a logic 1, which resets flip-flop FF1 to the call waiting mode. )
A logic zero at the output of set flip-flop FF1 causes AND gate G9 (FIG. 4D) to generate a logic zero, so that the speed of the pulses generated by clock generator 16 is controlled by the state of gate G8. will be done. A logic one from the Q output of set flip-flop FF1 is also applied to AND gate G4 (FIG. 4A) along with whatever logic signal is generated by inverter I2 (FIG. 4B). applied. If the search generator 13 (FIG. 4D) encounters a busy channel when the operator switches to the call origination mode, the signal sensing device in the receiver will generate a logic 1, which is inverted to a logic 0. To become, Gate G
4 generates a logic zero. This allows you to continue your search. When the search generator 13 reaches a free channel (which is indicated by the absence of a carrier or busy tone), the signal sensing device of the receiver generates a logic zero. Since this logic 0 is inverted to logic 1 by inverter I2,
Gate G4 generates a logic one. This logic 1 sets flip-flop FF3 (Figure 4B),
During the remainder of the call origination sequence, the Q output
Generates a logic 1. This logic 1 from flip-flop FF3 causes NOR gate G2 (4th D
Since gate G6 generates a logic 0, gate G6 prevents clock pulses from being sent to search generator 13 during the remainder of the call origination sequence. Logic 1 from flip-flop FF3 is AND gate G
18 (FIG. 4B) and generator 16 (FIG. 4B).
A clock pulse from the shift register SR1 (FIG. 4B) is applied to the clock input of shift register SR1 (FIG. 4B). Shift register SR1 has already been reset, so the circulating logic 1 is in stage 1.

The logic 0 at the output of the set flip-flop FF1 is inverted to logic 1 by the inverter I1 (Fig.
is applied to AND gate G8 along with a logic 1 from FIG. 1, causing clock generator 16 to pulse at a fast rate until a free channel is reached. Reach a free channel and flip-flop
When FF3 is set, the logic 1 at its Q output is inverted to a logic 0 by inverter I3, so that AND gate G8 generates a logic 0. Gate G9 has already generated a logic zero. These two logic zeros cause generator 16 to generate clock pulses at a slow rate. This pulse is applied to gate G18 (FIG. 4B), causing shift register SR1 to operate in a slow manner. Inverter I
1 is generated by the signal tone circuit TC.
2. Set TC3 and TC4 to encoding format. At the beginning of the calling sequence, a logic 1 is in stage 1 of shift register SR1. This logic 1 is applied to AND gate G19 (FIG. 4B) along with the input from the signal sensing device which generates a logic 0 when the signal is not present. Therefore, gate G19 is OR gate G2
1 (FIG. 4B), the search generator 13 stays in an empty channel.

In call origination order, a slow clock pulse passes through gate G18 and a logic 1 is shifted from stage 1 to stage 2 of shift register SR1. This logic 1 is applied by OR gate G22 (Fig. 4B) to switch S4 (Fig. 4C), as well as to tone circuit TC1, switching it to encoding mode. The signal tone circuit TC1 generates a busy tone of 3000 Hz, which passes through the switch S4, is amplified by the signal tone amplifier 51, and is applied to the transmitter 11 of the mobile station. Shift register SR1
A logic 1 in stage 2 passes through OR gate G14 and keys the mobile station's transmitter 11 so that a busy tone is transmitted to the repeater. As mentioned before,
The repeater transmitter 33 of FIG. 3 is activated by receiving this busy tone and transmits a new busy tone to the mobile station via the selected channel. After the appropriate number of clock pulses, the logic 1 in stage 2 is transferred to stage 3 of shift register SR1. This transfer opens switch S4 and the busy tone disappears. The logic 1 transferred to stage 3 of register SR1 passes through gate G14 and is transmitted to transmitter 11 of the mobile station.
keying. This logic 1 is the signal tone circuit
It is also applied to switch S5 (FIG. 4C) attached to TC2. Signal tone circuits TC2, TC3 are already in encoding mode. When switch S5 closes, the group tone (e.g. 1050 Hz) generated by coded tone circuit TC2 is applied to tone amplifier 51 and keyed transmitter 11, which transmits the group tone. to the repeater, which then retransmits it to the mobile station. This logic 1 holds for a period of time long enough to allow all search generators of other mobile stations to pass through all five stages of their respective shift registers SR2 (Figure 4D). , is held in stage 3 of register SR1. This is because it is possible that the search generator has just left the contacted channel when communication is set up. Stations within the selected group begin responding.

After the appropriate number of clock pulses, the logic one in shift register SR1 shifts from stage three to stage four. This transfer ends the group tone generated by the encoder of the tone circuit TC2.
The logic 1 in stage 4 passes through gate G14 and keys the transmitter 11 of the mobile station. This logic 1 is also provided to close switch S6 (FIG. 4C) via subgroup select switch 46 (FIG. 4A) and its contacts. (If selection switch 46 is in position 2, a logic 1 from stage 4 is applied to switch S7.) A tone from small group tone circuit TC3 (e.g.
400 Hz) is sent to the signal tone amplifier 51 via switch S6 and applied to the transmitter 11. The transmitter is keyed and sends the tone to the repeater, which retransmits the tone to other mobile stations.

After the appropriate number of clock pulses, a logic one shifts from stage 4 to stage 5 of shift register SR1. This transfer ends the small group tone generated by the encoder of tone circuit TC3. In this state, no logic 1 is applied to gate G14, so that the transmitter 11 of the mobile station is not keyed. Also, as mentioned earlier, when a logic 1 is shifted from stage 2 to stage 3 of shift register SR1, one input of OR gate G22 becomes logic 0.
and the other input is logic 0 (this is because flip-flop FF2 is still in the reset state and the switch remains open), so the signal tone circuit TC1 is switched to the busy tone decoding mode. There is. Since the transmitter is not keyed, the receiver is activated and listens to the selected channel. By this time the repeater should have been activated and keyed and there should be busy tone on this channel. If busy tone is present and received by the receiver of the calling mobile station,
This tone generates a logic 1 at the Q output of the decoder of the tone circuit TC1. This logic 1 is the shift
Together with the logic 1 from stage 5 of register SR1, it is applied to AND gate G23 (FIG. 4A), causing gate G23 to generate a logic 1. This logic 1 is sent to flip-flop FF1 via OR gate G1.
is applied to the reset input R of the flip-flop to reset the flip-flop and stop the calling sequence. When flip-flop FF1 is reset, the waiting light 40 goes out. The logic 1 from gate G1 also resets flip-flop FF3 and its Q output switches to a logic 0, preventing any more clock pulses from passing through AND gate G18 (Figure 4B). A logic 1 from gate G23 sets flip-flop FF2 through OR gate G13 (FIG. 4A) and also sets or starts timer T2. When flip-flop FF2 is set, its Q output switches to logic 1,
For this reason, the ready light 41 turns on, and the switch S
1, S2, S3 are closed, signal tone burst generator 5
0 is asserted, indicating that the operator has acquired the channel. Switch S1, S
2. When S3 is closed, the speaker 44 is connected to the receiver 12.
The microphone 42 and press talk button 43 are connected to the transmitter 1 through the gate G14.
Connected to 1. If the operator removes the microphone 42 from switch 45 before the expiration of timer T2 (if used), a positive voltage or logic 1 is applied through the response contact and timer T2
, so its output remains at logic 0 and flip-flop FF2 remains set. Since flip-flop FF2 is held in the set state, a logic 1 on its Q output ensures that gate G2 generates a logic 0, thus applying a clock pulse to search generator 13 to set the set channel. Cannot be switched. Each time the operator presses the press talk button 43, the generated logic 1 passes through the OR gate G22 (FIG. 4B) and a busy tone is supplied from the signal tone circuit TC1 to the mobile station transmitter 11. .

In the order stated above, a logical 1 indicates a shift register.
When in stage 5 of SR1, if no busy tone is detected by the decoder of signal tone circuit TC1, flip-flop FF1 remains in the set state, flip-flop FF2 remains in the reset state, and flip-flop FF3 remains in the set state. Stay in the state. This allows gate G18 to pass another clock pulse, shifting the logic one from stage five to stage six. As a result, the counter circuit 60 (FIG. 4B)
produces a logic 1 at its output. Next clock
When a pulse is received, this logic 1 is fed back from stage 6 to the feedback input D of stage 1 of shift register SR1. Upon receipt of further clock pulses, the sequence described above is repeated, starting with stage one. If a busy tone from the repeater is heard when the logic 1 reaches stage 5, flip-flop FF2 is set and flip-flop FF1 is reset, indicating that the operator has acquired the channel. The operator must turn microphone 4 on before timer T2 (if used) expires and is reset.
2 should be taken up. However, if no busy tone is heard in stage 5 of this second order register SR1, a logic 1 is shifted to stage 6, which, together with the logic 1 in counter 60, is connected to AND gate G24.
(Figure 4B) generates a logic 1, and this logic 1
passes through OR Gate G20 (Figure 4B),
Reset shift register SR1. At the times listed above (17 stages of shift register SR1 and 60 ms between pulses), the shift register
The total time required to complete the sequence through SR1 twice is:
It takes about 2 seconds. A logic one from gate G24 passes through OR gates G21 and G7 (FIGS. 4B and 4D) and into the clock input of shift register SR2 in search generator 13. This causes shift register SR2 to shift to the next stage and set the transmitter and receiver frequencies to the corresponding next channel. The clock pulses are sent to the sequence generator 17.
The shift register SR1 in the register SR1 is advanced in the above-mentioned order. If the following channels are used:
The signal sensing device of the receiver generates a logic 1 which, together with the logic 1 in stage 1 of shift register SR1, generates a logic 1 from AND gate G19. This logic 1 passes through OR gates G21, G7 and shifts shift register SR2 to the next stage (and corresponding channel). shift·
This short sequence continues until a free channel is found in stage 1 of register SR1, followed by a sequence from stage 1 to stage 5 or through stage 6 twice.
The maximum time it takes for shift register SR1 to completely traverse all five channels, twice in sequence, is approximately 10 seconds. If no channel is found, timer T1 is reset and its output becomes logic one. This logic 1 is flip-flop FF1
, puts the device into a call-ready mode (i.e., an operating state in which it is ready to receive a call and switch to making a call) and extinguishes the wait light 40 so that the operator can begin the call origination sequence again. I see that it can be done.

If the channel is successfully acquired, the operator can communicate. As mentioned earlier, since the repeater is equipped with a timer 35 (Figure 3), it is necessary for the repeater to receive a signal tone during the timing period in order to acquire the channel. . After the call or communication is completed, returning the microphone to the switch 45 returns control to the call standby mode. This causes a positive voltage, or logic 1, to reset flip-flops FF1 and FF3 through capacitor C5 and OR gate G1, as well as to reset flip-flops FF1 and FF3 through capacitor C1 and OR gate G16.
Reset flip-flop FF2 via.
These Q outputs return to logic zero. Since the group tone decoder in circuit TC2 produces a logic 0, AND gate G5 also produces a logic 0. Therefore, all inputs to NOR gate G2 are logic zeros, and NOR gate G2 generates a logic one, passing the fast clock pulses from generator 16 to search generator 13 through gate G6. Make it possible to send it. If the mobile station operator ignores the microphone to return the radio to call standby mode after a call ends, the busy tone circuit TC
A logic 1 from 1 keeps capacitor C6 (Figure 4B) charged to a logic 1 via diode D1 (Figure 4B). During the time the press talk button 43 is pressed, the resistor 66 connects to the capacitor C6.
remains charged to logic 1. When the repeater time expires (busy tone ends), capacitor C
6 discharges to logic 0. Inverter I4 is logic 1
is generated, which passes through gate G16, resets flip-flop FF2, and returns the control state to the call standby state. Therefore, the user cannot stop at a certain channel by accident.

Briefly summarized, when the device is in call origination mode, shift register SR2 scans at high speed until a free channel is found. This causes shift register SR1 to forward the busy tone group tone and small group tone from the transmitter to advance the sequence of activation of the repeater and the appropriate mobile station. Once the repeater is activated, an indication will be given to the operator that he has acquired the channel and he should transmit within the scheduled time (15 seconds). If the repeater is not activated, the shift register SR1 advances the sequence from one channel to the next until a channel is obtained or all channels have been examined. If no channel is obtained, the user can start the entire sequence again.

Accordingly, there is a novel technology that allows a transceiver operator to easily and quickly acquire a radio frequency channel among a plurality of channels in order to transmit on an available channel or to be called upon. It will be appreciated that improved control circuits and methods have been provided. This control scheme is relatively simple and does not require extensive or complex circuitry. Although only one embodiment of the invention has been shown, many modifications will occur to those skilled in the art. For example, although a five-channel system is shown, the number of channels and repeaters may be almost arbitrary. However, for good relay operation, the number of channels is limited to about 20. Different logic circuit types and logic levels can be used, such as microprocessor circuits. The various circuits, particularly shift register SR1 and timing circuits T1, T2, may have almost any desired timing period. Timers and counters may be of either analog or digital type. Timer T2 can be omitted by disconnecting its output from gate G16 so that the user does not have to respond in call waiting mode to stay on the set channel. These are matters of preference and convenience that depend on the particular communication conditions involved. If this method is not affected by electromagnetic interference,
The busy tone may be omitted and the operation may be performed depending on the presence or absence of an appropriate carrier wave. In addition, the signal sensing device of the receiver generates a logic 1 in response to a busy tone, and
Preferably, a logic zero is generated in response to the absence of busy tone. In the call waiting mode, by connecting switch S8 to logic 1 (+V),
The busy tone condition may be omitted from AND gate G12 and may also be omitted from AND gate G5 by connecting switch S9 to logic 1 (+V). In call origination or call waiting mode, stage 1 of shift register SR1 may be omitted. The fast-slow gates G8, G9, and G10 may be omitted and the clock generator 16 may operate at one speed. Although one group of circuits and two subgroups of circuits from which one may be selected are shown, additional subgroups may be provided to further select the particular mobile station to be called. It may be possible to do so. Alternatively, the number of subgroup circuits may be reduced to allow more mobile stations to be called in general or fewer selected groups. The group and subgroup tones may be transmitted simultaneously, rather than sequentially, or may be step functions relative to one common encoder and decoder frequency. This method may be used directly between mobile stations without using repeaters. Those skilled in the art will appreciate that by using the repeater's transmit frequency and the repeater's receive frequency, only pre-talk or simplex operation can be performed. However, additional channels may be provided to allow full duplex communication operation. This is also a matter of preference and available frequencies. Although it is preferred that the busy tone frequency be higher than the audio frequency for faster operation, the busy tone may be at almost any desired frequency. Similarly, the group and subgroup tones may be at almost any desired frequency. However, it is preferred that the busy tone be at a frequency just above the audible frequency that is transmitted, and that the group and subgroup tones be within the audio frequency band that is transmitted. This poses no problem since group and small group tones are only transmitted when communication is established. Therefore, while this invention has been described with respect to particular embodiments, it will be understood that various modifications may be made within the scope of the invention.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a terrestrial mobile communication system using the method of this invention, Fig. 2 is a block diagram of the method of this invention used in a mobile vehicle, Fig. 3 is a block diagram of a device used in a repeater, and Fig. 4A. FIGS. 4A to 4D are together a detailed circuit diagram of an example of a device used in a mobile vehicle, and FIG. 5 is a diagram showing the interrelationship of FIGS. 4A to 4D. Explanation of main codes, 11: Mobile station transmitter, 1
2: Mobile station receiver, 13: Search generator, 14:
Operator control device, 15: control circuit, 16: clock generator, 17: sequence generator, 18: tone encoder, decoder and gating device.

Claims (1)

[Claims] 1. In a method for setting up wireless communication from a first wireless station to a second wireless station via a wireless repeater using a wireless channel selected from a plurality of wireless channels, (a ) Set the first wireless station to a call origination mode, scan the plurality of wireless channels until an empty channel without a busy signal is found, and operate the first wireless station on the found empty channel, ( b) transmitting a busy signal from the first wireless station to the repeater to cause the repeater to operate on the free channel; (c) retransmitting by the repeater to the second wireless station; at least one scheduled group signal for operating the first
(d) checking at the first wireless station whether there is a busy signal transmitted from the repeater on the free channel; (e) putting the second wireless station into a call standby mode and transmitting the plurality of signals until a channel having the scheduled group signal is found in the second wireless station; (f) operating the second wireless station on the channel having the found scheduled group signal; A communication setting method comprising the steps of communicating with the second wireless station via the repeater in response to the busy signal. 2 If the repeater fails to transmit the busy signal on the free channel, the first wireless station sends the busy signal to the repeater again to operate the repeater on the free channel. and then
transmitting the scheduled group signal for operating the second wireless station by retransmission by the repeater from the first wireless station to the repeater again on the empty channel; By receiving the free channel at a wireless station, it is determined whether the repeater is transmitting the busy signal from the repeater on the free channel, and the repeater is transmitting the busy signal. in response, the first wireless station communicates with the second wireless station via the repeater, and the first wireless station receives the busy signal transmitted from the repeater on the free channel. 2. The method of claim 1, wherein scanning of the plurality of channels is resumed when a signal is not detected. 3. A device for setting up communication between a first radio station and a second radio station among a plurality of radio stations via a relay station on one of the plurality of radio frequency channels. a first means for placing the first wireless station in a call standby mode and causing the first wireless station to start scanning the plurality of radio frequency channels; one of the plurality of channels; in response to a scheduled group signal being transmitted on one channel, stopping the scanning initiated by the first means and causing the first wireless station to operate on the one channel to second means for causing the first wireless station to respond to the scheduled group signal on a channel; and third means for placing the first wireless station in a call origination mode to initiate scanning of the plurality of channels by the first wireless station. , and stopping the scanning started by the third means on one of the plurality of channels, checking whether there is a scheduled busy signal on the one channel, and checking whether there is a scheduled busy signal on the one channel, If there is no busy signal, it is determined that the one channel is an empty channel, and the first wireless station is operated on the one channel, and if there is the scheduled busy signal, the scanning is continued. A communication setting device comprising: fourth means for setting. 4 causing the first wireless station activated by the fourth means to transmit a busy signal to the relay station on the one channel to activate the transmitter of the relay station; 4. The apparatus for setting up communications according to claim 3, further comprising fifth means for checking whether a transmitter of said activated relay station is operating on said one channel. 5. The communication setup of claim 4, wherein the activated relay station transmitter transmits a busy signal on the one channel in response to the busy signal from the first wireless station. Device. 6. The communication setting device according to claim 3, further comprising means for causing the first wireless station to transmit a scheduled group signal tone.