Arrangement and method for establishing radio communication in a system

• US 4,409,687 A
• Filed: 04/14/1981
• Issued: 10/11/1983
• Est. Priority Date: 10/30/1978
• Status: Expired due to Term

• Current Assignee: Ericsson GE Mobile Communications Inc (Telefonaktiebolaget LM Ericsson)
• Original Assignee: General Electric Company
• Inventors: Williams, James W., Berti, John C.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US06/254,080
• Time in Patent Office: 910 Days
• Field of Search: 455/7, 455/15, 455/17, 455/18, 455/31, 455/32, 455/34, 455/35, 455/36, 455/53, 455/54, 455/56, 455/58, 340/311.1, 340/825.48, 340/825.47, 340/825.52, 179/2 EB, 370/93, 370/95
• US Class Current: 455/7
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

Communication between a first radio transmitter and receiver and a second radio transmitter and receiver is provided by a system repeater. An arrangement for each radio transmitter and receiver in the system establishes communication on a radio frequency channel selected from a plurality of such channels. When an arrangement is in an idle or receive mode, it causes the associated receiver to search the channels for a predetermined group tone or tones assigned to each receiver. When the predetermined group tone or tones are received on a channel, the arrangement enables the associated transmitter and receiver on that channel. When an arrangement is in a call originate or transmit mode, it causes the associated receiver to search for an idle or unused channel. When an idle channel is found, the arrangement enables the associated transmitter and receiver on that channel, and causes the transmitter to transmit a busy tone and the predetermined group tone or tones so as to enable the other transmitters and receivers of the predetermined group on that same channel.

Claims

1. An arrangement for establishing communication 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, said arrangement comprising:

a. first means for placing said first station in an idle mode and for causing said first station to scan said radio frequency channels;

b. second means for stopping the scan caused by said first means in response to a predetermined group signal transmitted by said repeater on one of said channels, and enabling said first station to be operated on said one channel in response to said predetermined group signal thereon;

c. third means for alternatively placing said first station in a call originate mode and for causing said first station to scan said radio frequency channels; and

d. fourth means for stopping the scan caused by said third means on one of said channels and listening for a predetermined busy signal on said one channel and in response to the absence of said predetermined busy signal on said one channel, determining that said one channel is non-busy and enabling said first station to be operated on said non-busy channel in response to said absence of said predetermined busy signal thereon, and in response to the presence of said predetermined busy signal, continuing said scanning.

2. The arrangement of claim 1 and further comprising fifth means for causing said first station enabled by said fourth means to transmit a busy signal on said one channel to said repeater to operate said repeater transmitter, and for causing said first station to then listen for said operated repeater transmitter on said one channel.

3. The arrangement of claim 2 wherein said operated repeater transmits said busy signal on said one channel in response to receiving said busy signal from said first station.

4. The arrangement of claim 2 or 3 wherein said fifth means further includes means for causing said enabled first station to transmit said predetermined group tone.

5. An arrangement for establishing communication over a two-frequency radio channel between a first station and a second station through a repeater, said arrangement comprising:

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

b. second means for alternatively placing said station in a call originate mode and for causing said first receiver to scan the radio frequency channels, to stop said scanning caused by said second means on one of said channels and listening for a predetermined busy signal on said one channel and in response to the absence of said predetermined busy signal on said one channel, determining that said one channel is non-busy and arranging for said first station and said repeater to operate on said one channel in response to said absence of said busy signal thereon and in response to the presence of said predetermined busy signal, continuing said scanning.

6. The arrangement of claim 5 wherein said second means further causes said operated first station to transmit said busy signal for operating said repeater on said one channel.

7. The arrangement of claim 6 wherein said second means further causes said operated first station to transmit said predetermined group signal to said operated repeater and wherein said operated repeater retransmits and predetermined group signal to said second station.

8. An arrangement for establishing communication between a first radio station and a second radio station over one of a plurality of radio channels comprising:

a. means for selectively placing said first station in an idle mode or in a call originate mode;

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

c. a sequence generator responsive to said selective placing means being in said call originate mode for causing said first radio station to transmit said busy signal on said channel having no busy signal thereon, for thereafter causing said first radio station to be receptive to signals on said channel, and for thereafter indicating that communication is established in response to a predetermined signal received on said channel after the transmission of said busy signal by said station.

9. The arrangement of claim 8 wherein said sequence generator comprises means for causing said first station to transmit an initial group signal as well as said busy signal and wherein said received predetermined signal indicative of established communication comprises a continuous busy signal.

10. The arrangement of claim 9 and further comprising a repeater including a transmitter and receiver for operation on each of said radio channels.

11. The arrangement of claim 10 wherein said received predetermined signal indicative of established communication comprises a continuous busy signal transmitted by said repeater.

12. 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, said arrangement comprising:

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

b. a sequence generator for providing the sequence of first causing said search generator to tune said first radio station to receive on each of said channels in sequence and locate an idle channel defined by the absence of a predetermined busy signal thereon, second causing said first radio station to transmit a busy signal on said idle channel, third causing said first radio station to transmit a group signal on said idle channel, said fourth stopping said transmission and causing said first station to listen for a busy signal on said idle channel; and

c. means, coupled to said search generator, for selectively causing said first radio station to become enabled for communication on a channel having a predetermined signal thereon, or for selectively causing said sequence generator to enable said first radio station for communication on said idle channel in response to reception of a busy signal on said idle channel during the listening in said sequence generator sequence.

13. The arrangement of claim 12 wherein said sequence generator sequence is repeated in response to the absence of a busy signal on said idle channel when said first radio station listens on said idle channel.

14. 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:

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

b. transmitting by said first radio station a busy signal to said radio repeater to enable said radio repeater on said idle channel;

c. transmitting by said first radio station at least one predetermined group signal to said radio repeater on said idle channel for retransmission by said radio repeater to enable said second station;

d. listening for a repeater transmitted busy signal on said idle channel at said first radio station to determine whether said radio repeater is transmitting on said idle channel;

e. placing said second radio station in an idle mode and scanning said plurality of channels by said second radio station until said predetermined group signal is located and enabling said second station on said channel having said predetermined group signal; and

f. communicating by said first radio station with said second radio station through said radio repeater in response to said repeater transmitted busy signal on said idle channel.

15. The method of claim 14 and, in response to the failure of said radio repeater to transmit said busy signal on said idle channel, comprising the further steps of:

g. again transmitting by said first station said busy signal to said radio repeater to enable said radio repeater on said idle channel

h. again transmitting by said first station said group signal to said radio repeater on said idle channel for retransmission by said radio repeater to enable said second station;

i. receiving by said first radio station on said idle channel to determine whether said radio repeater is transmitting said repeater transmitted busy signal on said idle channel; and

j. communicating by said first radio station with said second radio station through said radio repeater in response to said radio repeater transmitting said busy signal, or resuming scanning said channels in response to a failure of said first station to detect said repeater transmitted busy signal on said idle channel.

16. 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:

a. scanning by said first radio station said plurality of channels until an idle channel without any busy signal thereon is located, and enabling said first station on said idle channel;

b. transmitting by said first radio station a busy signal to said radio repeater to enable said radio repeater on said idle channel;

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

d. receiving by said first radio station on said idle channel to determine whether said radio repeater is transmitting a busy signal on said idle channel, and

e. communicating by said first radio station with said second radio station through said radio repeater in response to said repeater transmitted busy signal on said idle channel.

17. An improved trunking system for a plurality of mobile radio stations, each having a transmitter and receiver capable of operating on associated frequencies of a plurality of channels, and a radio repeater having a transmitter and receiver for the associated frequencies of each of said plurality of channels, said trunking system comprising at each of said mobile radio stations:

a. first means for selectively placing said mobile radio station in an idle mode or a call originate mode;

b. a search generator coupled to said first means and to the radio transmitter and receiver of said mobile station for sequentially tuning said radio transmitter and receiver to each of said channels in response to said idle mode or in response to said call originate mode;

c. a decoder connected to said radio receiver for producing first decode signals in response to said radio receiver detecting a predetermined signal and at least one predetermined group signal generated by another radio station on a channel to which said receiver had been tuned by said search generator;

d. second means coupling said decoder to said search generator for supporting said search generator in response to said first decode signals so that said radio transmitter and receiver are tuned to the corresponding channel having said busy signal and said at least one predetermined group signal;

e. third means coupled to said radio receiver and to said first means for producing an idle signal in response to the absence of a signal on a channel and in response to said call originate mode;

f. fourth means connecting said third means to said search generator for stopping said search generator in response to said idle signal so that said radio transmitter and receiver are tuned to the idle channel;

g. a sequence generator connected to said third means for producing an establishing a sequence of a busy period, a group period, and a first check period in response to said idle signal;

h. an encoder connected to said radio transmitter for causing said radio transmitter to transmit selected signals;

i. fifth means connecting said encoder to said sequence generator for producing a busy signal and a group signal in response to said busy period and said group period respectively;

j. sixth means connecting said sequence generator to said decoder in response to said check period;

i. and seventh means connected to said sequence generator, said decoder, and said radio transmitter and receiver for enabling said radio transmitter and receiver in response to a second decode signal produced by said decoder during said check period.

18. The improved trunking system of claim 17 wherein said second decode signal is produced by said decoder in response to said busy signal being received by said receiver during said first check period.

19. The improved trunking system of claim 17 or 18 wherein said seventh means causes said sequence generator to produce a second check period in response to the absence of said second decode signal during the first check period.

20. The improved trunking system of claim 19 wherein said radio transmitter and receiver are enabled in response to a second decode signal produced during the second check period, and wherein said search generator is sequentially advanced in response to the absence of a second decode signal during said second check period.

21. The improved trunking system of claim 17 and further including timing means connected to said first means for placing said mobile radio station in said idle mode after a predetermined time following said first means placing said mobile radio station in said call originate mode.

22. The improved trunking system of claim 18 and further including timing means connected to said first means for placing said mobile radio station in said idle mode after a predetermined time following said first means placing said mobile radio station in said call originate mode.

23. The improved trunking system of claim 19 and further including timing means connected to said first means for placing said mobile radio station in said idle mode after a predetermined time following said first means placing said mobile radio station in said call originate mode.

24. The improved trunking system of claim 20 and further including timing means connected to said first means for placing said mobile radio station in said idle mode after a predetermined time following said first means placing said mobile radio station in said call originate mode.

25. An improved trunking system for a plurality of mobile radio stations, each having a transmitter and receiver capable of operating on associated frequencies of a plurality of channels, and a radio repeater having a transmitter and receiver for the associated frequencies of each of said plurality of channels, said trunking system comprising at each of said mobile radio stations:

a. first means for selectively placing said mobile radio station in a receive mode or a transmit mode;

b. a search generator connected to said first means and to the radio transmitter and receiver of said mobile station for sequentially tuning said radio transmitter and receiver to each of said channels in response to said receive mode or in response to said transmit mode;

c. a decoder connected to said radio receiver for producing a first decode signal in response to said radio receiver receiving a busy signal and at least one predetermined group signal on a given channel, and a second decode signal in response to said radio receiver receiving a busy signal on said given channel;

d. second means connecting said decoder to said search generator for stopping said search generator tuning on said given channel in response to said first decode signal;

e. third means connected to said radio receiver and to said first means for producing an idle signal in response to the absence of a signal on a channel and in response to said transmit mode;

f. fourth means connecting said third means to said search generator for stopping said search generator tuning on said idle channel in response to said idle signal;

g. a sequence generator connected to said third means for producing an establishing sequence of busy, group, and check periods in response to said idle signal;

h. an encoder connected to said radio transmitter for causing said radio transmitter to transmit selected tones;

i. fifth means connecting said encoder to said sequence generator for producing a busy signal and a group signal in response to said busy period and said group period respectively;

j. sixth means connecting said sequence generator to said decoder in response to said check period;

k. and seventh means connected to said sequence generator, said decoder, and said radio transmitter and receiver for enabling said radio transmitter and receiver in response to said second decode signal being produced by said decoder during said check period;

and said trunking system comprising at said radio repeater;

l. means connecting the output of said receiver to the input of said transmitter for repeating;

m. and timing means connected to said receiver output and to said transmitter for maintaining said transmitter operative only during reception of said busy signal and for a predetermined time thereafter, and thereafter turning said transmitter off.

26. The improved trunking system of claim 25 and further comprising a busy tone generator connected to said repeater transmitter.

27. A radio communication transceiver capable of automatically establishing radio communication with another similar transceiver over an idle one of a plurality of selectable radio frequency channels, said transceiver comprising:

a radio receiver for receiving radio signals from an external source including both control and communication signals,

a radio transmitter for transmitting radio signals including both control and communication signals,

at least one control signal encoder and decoder connected to selectively detect predetermined received control signals and to selectively cause transmission of predetermined transmitted control signals,

a channel search generator connected to selectively cause said receiver and transmitter to operate on different ones of said radio frequency channels, and

control circuitry connected to control said encoder, decoder and channel search generator to operate

(a) in an idle mode to automatically scan at least the receiver over each of said channels, stopping to permit transceive operations over a particular channel if said predetermined received control signals are detected on that same channel, or, alternatively

(b) in a call originate mode to automatically locate an idle one of said channels by scanning, if necessary, said receiver, stopping on a channel, listening for a busy signal and to thereafter in the absence of a busy signal on said channel generate and transmit a busy signal on said channel and then generate and transmit control signals over that same channel and to permit transceive communication operations to thereafter occur on such channel.

28. A radio communication transceiver as in claim 27 wherein said channel search generator includes means to effect operation at a higher rate at least while searching for an idle channel than after finding one in the call originate mode.

29. A radio communication transceiver as in claim 27 wherein said control circuitry includes means which causes it to automatically revert to the idle mode if communication signals are not transmitted by said transmitter within a predetermined time after locating an idle channel in the call originate mode.

30. A radio communication transceiver as in claim 27, 28 or 29 wherein said control circuitry includes means which causes it to automatically revert to the idle mode if an idle channel is not located within a predetermined time after initiation of the call originate mode.

31. A radio communication system comprising plural transceivers as in claim 27 and further including a radio repeater disposed within each of said communication channels.

32. A radio communication system as in claim 31 wherein each said repeater includes:

a radio repeater receiver for receiving radio signals including both control and communication signals,

a detector connected to said repeater receiver for detecting at least some of said predetermined transmitted control signals after reception by said repeater receiver,

a radio repeater transmitter connected for retransmitting radio signals, including both control and communication signals, received by said repeater receiver except for said at least some control signals, and

a timer connected to said detector for automatically unkeying said radio repeater transmitter whenever said at least some control signals are not detected for a predetermined time period.

33. A radio communication system as in claim 32 wherein each said repeater includes a control signal generator connected to locally generate and cause transmissions of said at least some control signals in response to reception and detection of said at least some control signals.

34. A plural channel, trunked, radio communication system comprising:

plural radio transceivers,

plural radio repeaters, one for each of said channels, for establishing communication channels between said transceivers, and control means in each transceiver for causing each transceiver to operate in one of two modes;

(a) an idle mode wherein each of said plural channels is automatically scanned to detect the presence of predetermined control signals thereon transmitted by one of said repeaters and, if detected, to at least temporarily stop such scanning and to permit transceive communication operations over the same channel on which such control signals were detected, or

(b) a call originate mode wherein an idle channel is automatically detected, if available, and such detected idle channel is thereafter at least temporarily locked onto and used to permit transceive communication operations over that same channel by generating and transmitting a busy signal and predetermined control signals thereover and then listening for a busy signal on that same channel and establishing communication if a busy signal is received.

35. A plural channel, trunked, radio communication system as in claim 34 wherein said control means includes means which causes it to automatically revert to the idle mode if communication signals are not transmitted by said transmitter within a predetermined time after locating an idle channel in the call originate mode.

36. A plural channel, trunked, radio communication system as in claim 34 or 35 wherein said control means includes means which causes it to automatically revert to the idle mode if an idle channel is not located within a predetermined time after initiation of the cell originate mode.

37. A plural channel, trunked, radio communication system as in claim 34 or 35 wherein:

said control means includes means for causing a burst transmission of a control signal on said detected idle channel;

each of said repeaters includes means for causing a continuous transmission of a control signal on its channel in response to receipt and detection of said control signal from a transceiver; and

said control means includes means for permitting normal transceive operations on said detected idle channel in response to receipt and detection of said control signal from the respective repeater.

38. A radio communication transceiver capable of automatically establishing operation with another similar transceiver on an idle one of plural communication channels, said transceiver comprising:

a radio receiver means,

a radio transmitter means, and control means for causing operation in one of two modes;

(a) an idle mode wherein each of said plural channels is automatically scanned to detect the presence of predetermined control signals transmitted by another of said transceivers and, if detected, to at least temporarily stop such scanning and to permit transceive communication operations over the same channel on which such control signals were detected, and

(b) a call originate mode wherein an idle channel is automatically detected, if available, and such detected idle channel is thereafter at least temporarily locked onto and used to permit transceive communication operations over that same channel by generating and transmitting a busy signal and predetermined control signals thereover and then listening for a busy signal on that same channel and establishing communication if a busy signal is received.

39. A radio communication transceiver as in claim 38 wherein said control circuitry includes means which causes it to automatically revert to the idle mode if communication signals are not transmitted by said transmitter within a predetermined time after locating an idle channel in the call originate mode.

40. A radio communication transceiver as in claim 38 or 39 wherein said control circuitry includes means which causes it to automatically revert to the idle mode if an idle channel is not located within a predetermined time after initiation of the call originate mode.

41. A radio communication transceiver as in claim 38 further comprising:

means for automatically resuming operation in said idle mode if calling signals are not responded to by an operator within a predetermined time interval after their detected occurrence.

42. A radio communication transceiver as in claim 38 or 41 further comprising:

means for resetting said control means for operation in said idle mode upon operator actuation during said transceive communication operations.

43. A method of automatically establishing trunked plural channel radio communication, between plural transceivers, said method comprising the following steps at each transceiver site:

normally scanning each channel to detect the presence of predetermined control signals thereon transmitted by another of said plural transceivers and, if detected, at least temporarily interrupting the scan and permitting transceive operations to occur, and

upon command, interrupting said normal scanning step to search for an idle one of said channels, and, when detected, thereafter generating and transmitting predetermined control signals thereon including the transmission of a busy signal interrupted during an initial listening period when an answering busy signal is detected to permit transceive communication operations.

44. An arrangement for automatically establishing radio communication between plural transceivers on one of plural channels via a repeater, said arrangement comprising:

means for causing at least one of said transceivers to normally scan each channel to detect the presence of predetermined control signals transmitted by said repeater and, if detected, at least temporarily interrupting the scan and permitting transceive operations to occur solely on said last named channel via said repeater with at least one other of said transceivers, said transceive operations comprising transmission of a busy signal by one of said transceivers and receiving a corresponding busy signal transmitted by said repeater to enable the repeater to repeat message signals between said one and said one other transceiver.

45. An arrangement for automatically establishing radio communication between plural transceivers on one of plural channels via a repeater, said arrangement comprising:

means to cause at least one of said transceivers to search for an idle one of said channels by determining an absence of predetermined control signals and, when control signals transmitted by another of said plural transceivers are detected, thereafter exchanging busy signals by transmitting a busy signal to said repeater and detecting a corresponding busy signal transmitted responsively by said repeater on said last named channel with said repeater to permit transceive communication operations to occur via said repeater solely on said last named channel with at least one other of said transceivers.

46. An arrangement according to claim 45 wherein said transceive operations comprise said one transceiver being responsive to said repeater transmitted control signals to transmit control signals and message signals for repeating by said repeater.

47. An arrangement for automatically establishing radio communication between plural transceivers on one of plural channels via a repeater, said arrangement comprising:

means for causing at least one of said transceivers to normally scan each channel to detect the presence of predetermined control signals transmitted by another of said transceivers and repeated by said repeater on one of said channels and, if detected, at least temporarily interrupting the scan and permitting transceive operations to occur solely on said one channel with at least one other of said transceivers, and

command means located at said at least one of said transceivers comprising means for interrupting said normal scanning by said at least one of said transceivers to cause said last named transceiver to search for an idle one of said channels having no such control signals thereon and, when such signals are detected, thereafter generating and transmitting a busy signal and detecting a corresponding busy signal transmitted by said repeater thereover to permit transceive communication operations to occur via said repeater solely on said last named channel with at least one other of said transceivers.

48. A repeater arrangement for automatically establishing radio communication between plural transceivers capable of transmitting control signals on one of plural channels via a repeater, said arrangement comprising:

repeater means in said repeater for detecting the presence of transceiver originated first control signals received from a transceiver and in response enabling said repeater to transmit repeater originated control signals enabling said last named transceiver to thereafter transmit message signals together with second control signals, said repeater means being responsive to said first control signals for repeating said second control signals on one of said channels to another transceiver, said repeater means comprising further means responsive to further address control signals received from one of said transceivers on said one channel to repeat message signals therebetween on said channel, said repeater means transmitting said repeated second control signals continuously on said channel during repeating of message signals and for a predetermined time thereafter to indicate that said channel is being used for repeating.