Repeater trunking system

• US 4,360,927 A
• Filed: 03/12/1979
• Issued: 11/23/1982
• Est. Priority Date: 03/12/1979
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: General Electric Company
• Inventors: Williams, James W., Bowen, William A.
• Primary Examiner(s): NG, JIN FAY
• Application Number:
  US06/129,645
• Time in Patent Office: 1,352 Days
• Field of Search: 455/7, 455/8, 455/15, 455/17, 455/32-34, 455/54, 455/77, 455/78, 179/2 EB, 179/2 E, 370/24, 370/32
• US Class Current: 455/17
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

Arrangement for establishing communication between a first mobile radio station and a second mobile radio station through a repeater over a radio frequency channel selected from a plurality of such channels. In an idle mode, a mobile station searches the channels for a predetermined group signal identifying it as belonging to a particular group of mobile stations. When that predetermined group signal is received on a channel, the mobile station is enabled on that channel so that it can communicate with a call originating mobile station belonging to the same group. In a call originate mode, a mobile station searches for an idle or unused channel identified by the absence of a busy signal. When an idle channel is found, the call originating station transmits a busy signal. The repeater, hearing the busy signal, transmits an acquisition signal. This acquisition signal is detected by the call originating mobile station which thereafter transmits a predetermined group signal for enabling other mobile stations in the common group on that same channel.

Claims

1. In a system including a plurality of radio stations capable of communicating with one another via an enabled one of a plurality of repeaters, each repeater operating on a different channel wherein the channels being used are indicated by the presence of a marker signal appearing thereon and the channels being unused are indicated by the absence of such marker signal, an improved method for automatically establishing a dedicated communication channel between a call-originating first radio station and a call-receiving second radio station on a presently unused channel in response to a call-originating command signal generated at the first radio station, said method comprising the steps of:

automatically scanning by the first radio station of the plurality of channels to select an unused unmarked channel in response to said call-originating command signal; and

automatically exchanging signals on the thus selected channel between the first radio station and the repeater associated with the selected channel to enable the repeater on the selected channel, the exchanging of signals including (1) transmitting a busy signal from the first radio station, (2) receiving the busy signal at the thus selected repeater, (3) transmitting by the thus selected repeater of an acquisition signal different from the busy signal, and (4) receiving the acquisition signal at the first radio station, and only thereafter dedicating the thus selected repeater for communication between the first and second radio stations in response to successful completion of the entire exchanging step.

2. A method for establishing communication according to claim 1 wherein the step of scanning includes scanning the plurality of channels in a predetermined sequence beginning with a randomly selected channel.

3. A method for establishing communication according to claim 1 wherein the step of scanning includes scanning the plurality of channels in a predetermined sequence beginning with a predetermined one of said channels.

4. A method for establishing communication according to claim 1 wherein the step of scanning includes scanning the plurality of channels in a random sequence beginning with a randomly selected channel.

5. A method for establishing communication according to claim 1 wherein the step of scanning includes scanning the plurality of channels in a random sequence beginning with a predetermined one of said channels.

6. An arrangement for dedicating a communication channel between first and second radio stations through one of plural repeaters, each repeater being capable of relaying radio-frequency communications on a respectively corresponding communications channel, said arrangement comprising:

means at the first radio station responsive to a call-originate command for locating an unused one of the communication channels;

means at the first radio station for transmitting a busy signal to the corresponding repeater on the located unused channel;

means at the repeater for receiving the busy signal transmitted by the first radio station and for transmitting in response thereto an acquisition signal different from the busy signal on the located channel; and

means at the first radio station for receiving the acquisition signal transmitted by the repeater and generating and transmitting, in response thereto, a group signal on the located channel identifying a predetermined set of radio stations including the second radio station; and

means at the second radio station for receiving, via the repeater, the group signal, thereby dedicating a communication channel between the first and second radio stations via the repeater.

7. An arrangement according to claim 6 further including means at the repeater for transmitting a busy signal.

8. An arrangement according to either claims 6 or 7 wherein the means for locating an unused one of the communication channels comprises:

means for scanning the communication channels; and

means for stopping the scanning on a channel not having a predetermined signal thereon.

9. An arrangement according to either of claims 6 or 7 further including:

means at the second radio station for scanning the communication channels;

means for stopping the scanning in response to the detection by the second radio station of the group signal; and

means for establishing communication between the first and second radio stations through the repeater on the located channel.

10. In a system including a plurality of radio stations capable of communicating with one another through a repeater system operable on a plurality of channels, an improved method for establishing communication between a first radio station and a second radio station comprising the steps of:

exchanging signals on a first channel between the first radio station and the repeater system enabling the repeater on the first channel and dedicating that first channel of the repeater system for communications between the first and second radio stations in response to successful completion of the exchanging step;

repeating the exchanging step on a second channel in response to unsuccessful completion of the first exchanging step and continuing to attempt to exchange signals on each of the plurality of channels until a successful exchange has been completed;

after a successful exchange of signals between the first radio station and the repeater system on one of the plurality of channels, transmitting from the first radio station a signal for identifying the second radio station;

receiving at the second radio station the identifying signal transmitted by the first radio station and thereafter communicating between the first and second radio stations through the repeater system on the channel over which a completed exchange of signals between the first radio station and the repeater system took place.

11. A method for establishing communication according to claim 10 wherein the step of receiving at the second radio station includes scanning by the second radio station of the plurality of channels and stopping the scanning in response to the detection of the identifying signal.

12. An arrangement for dedicating a communication channel over one of a plurality of radio frequency channels between a first one of a plurality of radio stations and a second one of the plurality of radio stations through a repeater station, the arrangement comprising:

first means for placing the second station in an idle mode and for causing the second station to scan the radio frequency channels;

second means coupled to the first means for stopping the scanning in response to a predetermined group signal on a selected one of the channels, and enabling the second station to be operated on the selected channel in response to the predetermined group signal thereon so as to communicate with the first station on the selected channel;

third means for placing the first station in a call originate mode and for causing the first station to scan the radio frequency channels;

fourth means coupled to the third means for stopping the scanning on a non-busy channel in response to the absence of a busy signal on one of the plurality of radio frequency channels, and for enabling the first station to be operated on the non-busy selected channel in response to the absence of a predetermined busy signal thereon; and

means, within the repeater, for receiving on an unused channel, a busy signal and transmitting on that unused channel in response thereto an acquisition signal;

fifth means coupled to the fourth means for causing the enabled first station to transmit the busy signal on said selected channel to the repeater to operate the repeater, and for causing the first station to listen for an acquisition signal transmitted by the operated repeater on said selected channel, the successful exchange of busy and acquisition signals between the first station and the repeater being required for dedicating the selected channel for communication between the first and second stations by subsequent transmission of station selection signals from said first station through said repeater.

13. The arrangement according to claim 12 wherein the operated repeater transmits the acquisition signal on the one selected channel in response to receiving the busy signal from the first station.

14. An arrangement according to either of claims 12 or 13 wherein the fifth means further includes means for causing the enabled first radio station to transmit a predetermined group signal.

15. An arrangement for dedicating one of a plurality of two-frequency radio communication channels for communication between a first radio station and a second radio station through a repeater, said arrangement comprising:

a repeater which repeats information transmitted thereto on a first frequency of a two-frequency radio channel and re-transmits the information on a second frequency of the two-frequency radio channel, the repeater being activated by receiving a busy signal and transmitting in response thereto an acquisition signal;

first means for placing the first station in an idle mode and for causing the first station to scan the radio frequency channels, to stop scanning in response to a predetermined group signal detected on one of the channels, and to arrange the first station to be operated on the one channel in response to the predetermined group signal; and

second means for alternatively placing the first station in a call originate mode, the second means comprising;

means for causing the first radio station to scan the radio frequency channels;

means for stopping the scanning in response to the absence of a busy signal on one of the plurality of channels;

means for enabling the first radio station and the repeater on the one channel in response to the absence of a busy signal thereon;

means for transmitting a busy signal for operating the repeater on the one channel; and

means for detecting an acquisition signal transmitted by the repeater, the acquisition signal being different from the busy signal.

16. An arrangement according to claim 15 wherein the second means further causes the operated first radio station to transmit the predetermined group signal to the operated repeater and wherein the operated repeater retransmits the predetermined group signal to the second radio station.

17. An arrangement for dedicating one of a plurality of radio channels communication between a first radio station and a second radio station, comprising:

means for selectively placing the first station in either an idle mode or in a call originate mode;

a search generator coupled to and responsive to said means for selectively placing being in the idle mode for causing the first radio station to be sequentially tuned through the plurality of radio channels and stopping the sequential tuning on a channel having at least one predetermined group signal thereon, and responsive to said means for selectively placing being in the call originate mode for causing the first radio station to be sequentially tuned through the plurality of radio channels to locate a channel having no busy signal thereon; and

a sequential generator coupled to the means for selectively placing and to the search generator and responsive to the means for selectively placing being in the call originate mode for causing the first station to transmit a busy signal on the channel having no busy signal thereon, for thereafter causing the first radio station to be receptive on the channel, and for thereafter indicating in response to a received acquisition signal different from the busy signal received on said channel that the communication channel is dedicated for communication between the first and second radio stations.

18. An arrangement according to claim 17 further comprising a repeater radio station for operation on each of said plurality of radio channels, each repeater radio station operating to retransmit information transmitted thereto, after it has been dedicated to operate by receiving a busy signal transmitted thereto and transmitting in response to the busy signal, an acquisition signal.

19. An arrangement according to claim 18 wherein the received predetermined signal indicative of established communication comprises a continuous busy signal transmitted by the repeater radio station.

20. An arrangement for use with a first radio station to establish communication over a radio channel selected from a plurality of radio channels through a repeater to a second radio station, the arrangement comprising:

a search generator for causing the first radio station to become tuned to each of the channels in a repetitive sequence;

a sequence generator for providing the sequence of first causing the search generator to tune the first radio station to locate an idle channel, second causing the first radio station to transmit a busy signal on the idle channel, third causing the first radio station to listen for an acquisition signal transmitted by a repeater in response to reception by the repeater of the busy signal transmitted on the idle channel, fourth, causing the first radio station, in response to the acquisition signal to transmit a group signal identifying the second radio station on the idle channel, and fifth stopping the transmission and causing the first station to listen for a signal on the idle channel; and

means coupled to the search generator for selectively causing the first radio station to become enabled for communication on a channel having a group signal thereon specifying a group to which the first station belongs, or for selectively causing the sequence generator to enable the first radio station for communication on the idle channel in response to reception of an acquisition signal on the idle channel during the listening in the sequence generator sequence.

21. The arrangement of claim 20 wherein said sequence generator sequence is repeated in response to the absence of a signal on the idle channel when the receiver of the first radio station listens on the idle channel.

22. A method for dedicating a channel for communnication between a first radio station through a radio repeater and a second radio station over a radio channel selected from a plurality of such channels comprising the steps of:

placing the first radio station in a call originate mode and scanning the plurality of channels until an idle channel without busy signal is located, and enabling the first station on the idle channel;

transmitting by the first radio station a busy signal to the radio repeater to enable the radio repeater on the idle channel;

receiving by the radio repeater the busy signal transmitted by the first radio station;

transmitting by the repeater of an acquisition signal, different from the busy signal;

receiving at the first radio station the acquisition signal transmitted by the radio repeater;

transmitting by the first radio station in response to the acquisition signal at least one predetermined group signal to the radio repeater on the idle channel for retransmission by the radio repeater to enable the second radio station.

23. A method according to claim 22 further including the steps of:

scanning the plurality of channels by the second radio station in the idle mode until a predetermined group signal is located and enabling the second station on the channel having the predetermined group signal; and

communicating by the first radio station with the second radio station through the radio repeater in response to the repeater transmitting the busy signal on the idle channel.

24. A method according to claim 23 further including in response to the failure of said radio repeater to transmit said acquisition signal on said idle channel, the steps of:

again transmitting by the first station the busy signal to the radio repeater to enable the radio repeater on another idle channel;

again listening for the acquisition signal transmitted by the repeater;

again transmitting by the first radio station in response to the acquisition signal the group signal to the radio repeater on the idle channel for retransmission by the radio repeater to enable the second station;

again receiving by the first radio station on the idle channel to determine whether the radio repeater is transmitting the busy signal on the idle channel; and

communicating by the first radio station with the second radio station through the radio repeater in response to the radio repeater transmitting the busy signal, or resuming scanning said channels in response to the failure of the radio repeater to transmit the acquisition signal the idle channel.

25. A method for establishing radio communication from a first radio station through a radio repeater to a second radio station over a radio channel selected from a plurality of such channels comprising the steps of:

scanning by the first radio station the plurality of channels until an idle channel without busy signal is located, and enabling the first station on the idle channel;

transmitting by the first radio station a predetermined busy signal to the radio repeater to enable the radio repeater on the idle channel;

listening for an acquisition signal transmitted by the repeater in response to the busy signal transmitted by the first station;

transmitting by the first radio station at least one group signal to the radio repeater on the idle channel;

receiving by the first radio station on the idle channel to determine whether the radio repeater is transmitting the acquisition signal on the idle channel; and

communicating by the first radio station with the second radio station through the radio repeater in response to the radio repeater transmitting the acquisition signal on the idle channel.

26. A trunking radio transceiver comprising:

a radio receiver for receiving both control and communication signals selectively over each of a plurality of channels;

a radio transmitter for transmitting both control and communication signals selectively over each of a plurality of channels; and

a control unit, connected to control said receiver and transmitter, including means for operating the receiver and transmitter in both of the two following modes, operation occurring in either such mode, but not simultaneously;

(a) an idle mode where at least said receiver is repetitively scanned over said plurality of channels until a predetermined control signal is detected in one non-idle channel whereupon said scanning is interrupted and subsequent communication signal transceive operations are permitted on said one channel;

or alternatively,

(b) a call-originate mode where at least said receiver is scanned over said plurality of channels until an idle channel is detected whereupon, (1) said scanning is interrupted, (2) a first control signal is transmitted over said detected idle channel for a first predetermined time period, (3) a second control signal different from said first control signal is received and detected over said detected idle channel during a second predetermined time period, (4) at least one of said predetermined control signals thereafter continues to be transmitted over said detected idle channel to mark it as busy, and (5) communication signal transceive operations are permitted on said detected idle channel only if steps (2) and (3) are successfully completed.

27. A trunking radio transceiver including channel acquisition control means that, when in an idle mode, continuously and automatically scans for possible calling signals and busy-marking signals on each of plural channels and that, when in a call-originate mode, automatically scans for an idle unmarked channel in response to a call originate request signal and transmits a busy-marking signal to a repeater station over a detected previously unmarked idle channel and requires receipt of an answer-back acquisition control signal from the repeater station over that same channel before permitting transceive communication of information thereover via said repeater station, and wherein said channel acquisition control means comprises:

answer-back control means requiring receipt of an answer-bck acquisition control signal from the repeater station but different in information content from said busy signal, before permitting said transceive communication of information via said repeater station.

28. A trunking radio communication system comprising plural remote transceivers and plural repeaters, at least one repeater being provided for each of plural available channels, said system comprising:

transceiver channel acquisition control means in each transceiver which sequentially (1) automatically scans to detect and select an unmarked "idle" channel in response to a call-originate command signal, (2) automatically transmits a first acquisition control signal over said selected channel, and (3) automatically permits transceive communications thereover only after successful receipt and detection on that channel of a second acquisition control signal different from said first acquisition control signal, and

repeater channel acquisition control means in each repeater which (1) automatically detects said first acquisition control signal on its respective channel and in response, (2) automatically transmits said second acquisition control signal thereover only if its channel is truly in an idle status at that time.

29. A radio repeater for use on a given channel in a plural channel trunking radio communication system, said repeater comprising:

radio receiver means for receiving information signals on a dedicated radio receive carrier frequency;

radio transmitter means for automatically retransmitting said received information signals on a dedicated radio transmit carrier frequency; and

channel acquisition control means which (1) automatically receives and detects a first acquisition control signal on said receive frequency of the channel a second acquisition control signal, different in information content from said first control signal only if its channel comprising said dedicated receive and transmit carrier frequencies is truly in an unmarked idle status at that time and (3) which thereafter continues to cause transmission of a control signal over said transmit frequency to mark the channel as busy.

30. A trunking radio transceiver comprising:

a radio receiver,

a radio transmitter, and

channel acquisition control means which (1) automatically scans to detect an unmarked "idle" channel comprising a dedicated receive carrier frequency and an associated dedicated transmit carrier frequency in response to a call-originate request signal, (2) automatically transmits a first acquisition control signal over the dedicated transmit carrier frequency of said detected channel, and (3) automatically permits transceive communications thereover only after successful receipt and detection on the dedicated receive carrier frequency of that same channel of a second acquisition control signal different in information content from said first acquisition control signal.