Arrangement for cellular operation of a repeater trunking system

• US 4,347,625 A
• Filed: 06/16/1980
• Issued: 08/31/1982
• Est. Priority Date: 06/16/1980
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: General Electric Company
• Inventors: Williams, James W.
• Primary Examiner(s): NG, JIN FAY
• Application Number:
  US06/159,650
• Time in Patent Office: 806 Days
• Field of Search: 455/8, 455/9, 455/17, 455/32-34, 455/54, 455/62, 455/77, 455/78, 455/56, 370/24, 370/32, 179/2 EB, 179/2 E
• US Class Current: 455/17
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

An arrangement for the cellular operation of a repeater trunking system. In a repeater trunking system including a plurality of mobile stations communicating over a predetermined number of communication channels, each associated with a repeater, an arrangement for inhibiting attempted communication on channels not in a selected cell even though the mobile stations are capable of operation on the channels of non-selected cells.

Claims

1. In a repeater trunking system wherein a first plurality of radio stations communicate with one another via a first plurality of repeaters, each repeater operating on a different one of a first group of communication channels, said first group of channels constituting a first cell, and wherein a second plurality of radio stations communicate with one another via a second plurality of repeaters, each repeater operating on a different one of a second group of communication channels, said second group constituting a second cell and wherein a radio station originating a call scans potentially available communication channels to locate an unused channel and, upon locating an unused channel, initiates an attempted exchange of signals between the call originating radio station and the repeater operating on the located unused channel, a successful exchange of signals dedicating that repeater and unused channel to the use of the call originating station, an arrangement for the cellular operation of the call originating radio station comprising:

means for generating signals on each of the communication channels of both the first and second groups of communication channels for scanning to find an unused channel within either said first or second group;

means for initiating an attempted exchange of signals on each channel scanned to determine whether that particular communications channel is unused; and

means coupled to said generating means for selecting operation in either said first or second cell, the selection of a cell selectively inhibiting the completion of such an attempted exchange of signals on any channel not within the selected cell, whereby said radio station, operating in a call originate mode, scans only the channels of the selected cell.

2. An arrangement according to claim 1 wherein said means for generating includes means for generating said signals in a predetermined sequence.

3. An arrangement according to claim 1 wherein said means for generating includes means for generating said signals in a random sequence.

4. An arrangement according to any of claims 1, 2 or 3 wherein said means for generating comprises a synthesizer.

5. An arrangement according to any of claims 1, 2 or 3 wherein said means for generating comprises a crystal controlled oscillator.

6. An arrangement according to any of claims 1, 2 or 3 means for generating comprises:

a search generator for generating a signal indicative of a channel to be scanned; and

a synthesizer coupled to said search generator for generating a signal on a channel designated by the signal from said search generator.

7. An arrangement according to claim 1 wherein said means for generating comprises:

a search generator for generating a signal indicative of a channel to be scanned; and

a synthesizer coupled to said search generator for generating a signal on a channel designated by the signal from said search generator; and

wherein said means for inhibiting comprises;

a decoder having inputs coupled to said search generator for receiving said signal indicative of a channel to be scanned, said decoder providing a signal on one of a plurality of output lines, each output line corresponding to a single channel, said output lines coupled together in cells to form cell lines, each cell line corresponding to a group of channels having at least one channel;

a cell select switch means, coupled to said cell lines, for selecting one of said cell lines;

said cell select switch providing an inhibit signal responsive to signals on unselected cell lines from said decoder, said inhibit signal for coupling to a control circuit of said radio station for inhibiting the scan of a channel.

8. An arrangement according to claim 7 wherein said cell select switch means comprises a switch coupled to a logic gate, said logic gate providing said inhibit signal.

9. An arrangement according to claim 7 wherein said cell select switch means comprises a logic circuit.

10. In a repeater trunking system wherein a first plurality of radio stations communicate with one another via a first plurality of repeaters, each repeater operating on a different one of a first group of communication channels, said first group of channels constituting a first cell and wherein a second plurality of radio stations communicate with one another via a second plurality of repeaters, each repeater operating on a different one of a second group of communication channels, said second group constituting a second cell and wherein a radio station originating a call scans potentially available communication channels in order to locate an unused channel and upon locating an unused channel initiates an attempted exchange of signals between the call originating radio station and the repeater operating on the located unused channel, a successful exchange of signals dedicating that repeater and unused channel to the use of the call originating station, a method for the cellular operation of the call originating radio station comprising the steps of:

generating signals on each of the communication channels of both the first and the second groups of communication channels for scanning to find an unused channel within either the first or second group;

initiating an attempted exchange of signals for each channel scanned for determining whether a particular communications channel is unused; and

selecting operation in either said first or second cell, the selection of a cell selectively inhibiting the completion of an attempted exchange of signals on any channel not within the selected cell, whereby said radio station scans only the channels of said selected cell.

11. A method according to claim 10 wherein said step of generating signals includes generating signals in a predetermined sequence.

12. A method according to claim 10 wherein said step of generating signals includes generating signals in a random sequence.

13. A method according to claims 10, 11, or 12 wherein said step of generating comprises the step of generating signals with a synthesizer.

14. A method according to any of claims 10, 11, or 12 wherein said step of generating comprises the step of generating with a crystal controlled oscillator.

15. A method according to any of claims 10, 11, or 12 wherein said step of generating comprises the steps of providing with a search generator a coded signal indicative of a channel to be scanned;

and

generating a signal on a channel designated by the coded signal from said search generator.

16. A cell selecting arrangement for controlling the scan of a call originating radio station of the type including search means for generating scanning signals on each of a group of communication channels comprising:

a decoder, coupled to said search means, having a plurality of output lines, one for each channel capable of being scanned by said call originating radio station, said decoder generating a signal on the output line corresponding to the channel on which scanning signals are being generated;

cell select switch means, coupled to said output lines for selecting among predetermined groups of said output lines, each such group corresponding to a cell constituting a sub-set of channels, said cell select switch means generating an inhibit signal at an output thereof whenever a scanning signal is generated in a non-selected cell, said output of said cell select switch means being adapted to be coupled to said station for inhibiting a transmission of scanning signals on channels in a non-selected cell.

17. A cell selecting arrangement according to claim 16 wherein said cell select switch means comprises:

a switch coupled to the output lines of said decoder; and

a logic circuit, coupled to said switch, for generating an inhibit signal responsive to a signal on an output line of a non-selected cell.

18. A cell selecting arrangement according to claim 17 wherein said logic circuit further includes means for determining when said radio station is operating in a call originating mode and generates inhibit signals only when said radio station is operating in a call originating mode.

19. A cell selecting arrangement according to claim 16 wherein said cell select switch means includes means for selecting among predetermined groups automatically in response to a received signal.

20. A cell selecting arrangement according to claim 19 wherein said means for automatically selecting comprises:

means for receiving and demodulating said signal, and

means, responsive to said receiving and demodulating means, for actuating said cell select switch means.

21. A cell selecting arrangement according to claim 19 wherein said means for automatically selecting comprises:

a receiver for receiving and demodulating said signal;

a tone detector for decoding cell select information carried by said signal; and

a switch actuator responsive to said tone detector for actuating said cell select switch means.

22. An arrangement for enabling communicating between a call originating transceiver and a call receiving transceiver via one channel of either a first or a second plurality of communication channels, said first and second pluralities of communication channels constituting a first and second cell respectively, each of said transceivers being capable of scanning by the use of scanning signals all of said channels for a non-busy signal or an address signal, comprising:

means, within the call originating transceiver, responsive to a received coded signal indicating a particular cells to be selected for generating a selection signal indicative of a desired one of first and second plurality of channels;

means, within the call originating transceiver, for generating a transmit initiate signal;

means, within the call originating transceiver, responsive to the transmit initiate signal, said selection signal and each of said scanning signals for providing a control signal; and

means, within the call originating transceiver, responsive to said control signal for enabling communication between said call originating transceiver and call receiving transceiver via only one channel of the plurality of channels selected by the selection signal generating means.

23. A trunking transceiver comprising:

a radio receiver capable of selective operation on any one channel of a plurality of channels;

a radio transmitter capable of selective operation in a call originate mode of operation on any one channel of said plurality of channels;

means for dividing the plurality of channels into groups, each group comprising one or more channels; and

control means for selecting a particular group of channels and connected to inhibit said transmitter from normal operation in said call originate mode on any channel except those within a selected group of channels, the control means being operative to cause said receiver to scan all of the channels of all groups in search of any signals directed thereto unless the transceiver is placed in the call originate mode of operation.

24. A trunking transceiver as in claim 23 wherein said control means actually causes scanning of all said groups of channels during said call originate mode but also causes all channels to appear to be busy except for those within said selected group of channels.

25. A trunking transceiver as in claim 23 or 24 wherein said control means includes automatic group selection means for automatically selecting said selected group of channels.

26. Cell selection apparatus for use with a trunking transceiver including a radio receiver and transmitter, each capable of selective operation on any one of a group of N channels and control circuitry capable of causing said transmitter, in a call originate mode, to automatically search for an idle one of said N channels and to originate transceiver operations thereover, said apparatus comprising:

channel identification means having input connections for repeatedly receiving control signals corresponding to each of said N channels; and

cell definition means for defining a first sub-group M of said N channels and a second sub-group N-M of said N channels connected to said channel identification means for selectively providing a first output control signal representing a simulated busy channel status for said first sub-group M of said N channels and a second output control signal for use in permitting normal call originate mode transceiver operations to go forward for the remaining sub-group N-M of said N channels.