Trunked radio repeater system with multigroup calling feature

• US 5,274,837 A
• Filed: 03/30/1992
• Issued: 12/28/1993
• Est. Priority Date: 06/03/1987
• Status: Expired due to Term

• Current Assignee: Pine Valley Investments, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Dissosway, Marc A., Cooper, Gerald M., Hughes, Houston H. III, Childress, Jeffrey S.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): URBAN, EDWARD F
• Application Number:
  US07/860,159
• Time in Patent Office: 638 Days
• Field of Search: 455/33.1, 455/53.1, 455/54.1, 455/54.2, 455/56.1, 455/58.1, 455/7, 455/9, 455/11.1, 455/17, 455/34.2, 379/59, 379/60, 379/63
• US Class Current: 455/7
• CPC Class Codes: H04L 1/14 in which the signals are sent back to the transmitter to be checked ; echo systems
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 25/06 Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions. Message and transmission trunking capabilities are both present so as to maximize working channel usage without compromising channel access for high priority communications. During transmission trunking, called and calling transceivers return to the control channel after each transmission (and called transceivers may be inhibited from transmitting) but grant higher priority to calls from the other transceivers being communicated with to ensure continuity over an entire conversation. Additional functions and fault tolerant features further increase the versatility and reliability of the system.

Claims

1. A method for coordinating, regrouping and controlling the resources of a trunked radio repeater system from a central command radio unit, said system having a digital control channel and plural working channels, which working channels are assigned for temporary use by individual radio units specified by digital control signals on the control channel, said method comprising the steps of:

requesting a multigroup call for a plurality of different individual and/or group identifications by passing digital control signals over said control channel from a radio unit;

assigning a working channel for said multigroup call in response to said request by passing digital control signals over said control channel;

specifying a plurality of radio units to participate in said multigroup call by passing, over said assigned working channel, using digital control signals specifying a corresponding plurality of different individual and/or group identifications;

calling said plurality of radio units to said assigned working channel in response to said digital control signals passed by said specifying step by passing digital control signals over said control channel specifying said plurality of different individual and/or group identifications; and

operating said plurality of radio units specified to participate in said multigroup call on said assigned working channel in response to said digital control signals passed by said calling step on said control channel.

2. A method as in claim 1 wherein said specifying step includes passing a variable length multiblock call message over said working channel at substantially 9600 bits per second, said multiblock call message including a plurality of data blocks each of which includes a group and/or individual identification string at least 11 bits long.

3. A method as in claim 2 further including acknowledging said specifying step by passing a receive bitmap message from said central command radio unit to said radio unit over said assigned working channel, said bitmap message specifying which of said data blocks were not correctly received by said central command radio unit.

4. A trunked radio repeater system for permitting a central command radio unit to coordinate, regroup and control system resources, said system having a digital control channel and plural working channels, which working channels are assigned for temporary use by individual radio units specified by digital control signals on the control channel, said system comprising:

means for requesting a multigroup call for a plurality of different individual and/or group identifications by passing digital control signals over said control channel from a radio unit;

means for assigning a working channel for said multigroup call in response to said request by passing digital control signals over said control channel;

means for specifying a plurality of radio units to participate in said multigroup call by passing, over said assigned working channel, digital control signals specifying a corresponding plurality of different individual and/or group identifications;

means for calling said plurality of radio units to said assigned working channel in response to said digital control signals passed by said specifying means by passing digital control signals over said control channel specifying said plurality of different individual and/or group identifications; and

means for operating said plurality of radio units specified to participate in said multigroup call on said assigned working channel in response to said digital control signals passed by said calling means on said control channel.

5. A system as in claim 4 wherein said means for specifying includes means for passing a variable length multiblock call message at substantially 9600 bits per second, said multiblock call message including a plurality of data blocks each of which includes a group and/or individual identification string at least 11 bits long.

6. A system as in claim 5 further including means for acknowledging said data blocks passed by said specifying means by passing a receive bitmap message from said central command radio unit to said radio unit over said assigned working channel, said bitmap message specifying which of said data blocks were not correctly received by said central command radio unit.