Quasi-duplex radio system using bi-directional hole extension

• US 5,091,906 A
• Filed: 12/18/1989
• Issued: 02/25/1992
• Est. Priority Date: 12/18/1989
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Reed, John D., Rozanski, Walter J. Jr., Lynk, Charles N. Jr.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Chin, Wellington
• Application Number:
  US07/452,929
• Time in Patent Office: 799 Days
• Field of Search: 370/24, 370/31, 370/32, 370/94.1, 370/94.2, 370/95.1, 370/95.3, 379/59.63, 455/33, 455/34, 455/53, 455/54, 455/56, 455/58
• US Class Current: 370/278
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems
• CPC Class Codes: Y10S 370/913 Wireless or radio

Abstract

A method for interrupting a radio transmission in a quasi-duplex radio-frequency communication system. The method of the present invention includes the step of transmitting a signal (22), with periodically-occuring holes (24) therein, by a first communicatioin unit (10) to at least a second communication unit (12). The transmitted signal (12) includes an audio information portion (16) and information packets (23). Each information packet (23) specifies the time of occurence of the next hole (24). The second communication unit (12) initiates an interruption of the transmission made by the first communication unit (10) by transmitting an interrupt request signal (31) to the first communication unit (10) at a time specified by an information packet (23) received by the second communication unit (12). When the first communication unit (10) receives the interrupt request signal (31), it processes the interrupt request signal (23) to determine whether it complies with predetermined criteria. If the first communication unit determines that the interrupt request signal complies with the predetermined criteria, it transmits an acknowledgement signal allowing the second communication unit (12) to interrupt the transmission so that the second communication unit (12) may begin transmitting information to be received by at least the first communication unit (10).

Claims

1. In a radio-frequency communication system, a method for interrupting a radio transmission, comprising the steps of:

(a) receiving an information signal with a first communication unit;

(b) transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, with the first communication unit, the first signal comprising an audio information portion, representing the information signal, and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the first signal;

(c) receiving the first signal with a second communication unit;

(d) transmitting an interruption request signal with the second communication unit at a time when at least one of the plurality of periodically-occurring holes is occurring in the first signal, as specified by at least one information packet that is received with the second communication unit;

(e) detecting at least a portion of the interruption request signal with the first communication unit to determine whether the detected portion complies with a first set of predetermined criteria; and

(f) interrupting the transmission of the first communication unit, with the first communication unit, responsive to step (e), so that the second communication unit may begin transmitting information to be received by at least the first communication unit.

2. The method of claim 1 further comprising the steps of:

(e

     1) extending the duration of the hole occurring at the time that the first communication unit detects the detected portion of the interruption request signal, with the first communication unit, when the detected portion of the interruption request signal complies with the first set of predetermined criteria;

(e

     2) processing the interruption request signal with the first communication unit, to determine whether the interruption request signal complies with a second set of predetermined criteria;

(e

     3) transmitting an acknowledgement signal with the first communication unit when the first communication unit determines that the interruption request signal complies with the second set of predetermined criteria, the acknowledgement signal allowing the second communication unit to interrupt the transmission; and

(e

     4) detecting the acknowledgement signal with the second communication unit.

3. The method of claim 2 wherein the first set of predetermined criteria comprises:

whether the interruption request signal is of at least a predetermined level.

4. The method of claim 2 wherein the first set of predetermined criteria comprises:

whether correlation of the interruption request signal to an expected signal produces a value that is of at least a predetermined quantity.

5. The method of claim 1, further comprising the steps of:

(a

     1) sampling the information signal at a first rate, with the first communication unit, to produce a sampled information signal;

(a

     2) storing the sampled information signal, with the first communication unit;

(a

     3) modulating the information signal, with the first communication unit, at a second rate; and

(c

     1) decoding the first signal with the second communication unit, to provide a reconstructed information signal that is substantially identical to the information signal.

6. The method of claim 1, wherein step (c) comprises the steps of:

(c

     1) initiating an interruption of the transmission with the second communication unit by applying an audio signal to an audio-operated-switch in the second communication unit; and

(c

     2) storing a portion of the audio signal with the second communication unit.

7. The method of claim 6, further comprising the step of:

(g) transmitting a second signal with the second communication unit, the second signal comprising the portion of the audio signal that was stored.

8. In a radio-frequency communication system, a method for interrupting a radio transmission, comprising the steps of:

(a) transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, with a first communication unit, the first signal comprising an audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur;

(b) receiving the first signal with a second communication unit;

(c) receiving voice information having a duration shorter than a predetermined period, with the second communication unit;

(d) modulating a radio-frequency carrier with the voice information, to produce a modulated signal;

(e) transmitting a second signal having a portion comprising the modulated signal and a portion comprising a request for a short interruption, with the second communication unit at a time when at least one of the plurality of periodically-occurring holes is occurring in the first signal, as specified with an information packet that is received with the second communication unit;

(f) detecting at least a portion of the interruption request signal with the first communication unit;

(g) extending the duration of the hole occurring at the time that the first communication unit receives the detected portion of the second signal, with the first communication unit, for a period long enough to allow reception of the signal;

(h) demodulating the second signal with the first communication unit, to provide a demodulated signal; and

(i) presenting the demodulated signal to a person using the first communication unit, with the first communication unit.

9. In a radio-frequency communication system, a method for interrupting a radio transmission, comprising the steps of:

(a) receiving an audio signal representing speech having a plurality of naturally-occurring pauses therein, with a first communication unit;

(b) storing the audio signal for a predetermined period with the first communication unit;

(c) transmitting a first signal, with a first communication unit, after the predetermined period, the first signal comprising a plurality of holes of a predetermined duration, an audio information portion, and at least one information packet, specifying when will occur in the first signal, each hole coinciding in time with a pause in the speech represented with the audio signal;

(d) receiving the first signal with a second communication unit;

(e) transmitting an interruption request signal with the second communication unit at a time when at least one of the plurality of holes is occurring in the first signal, as specified with an information packet that is received with the second communication unit;

(f) detecting at least a portion of the interruption request signal with the first communication unit;

(g) extending the duration of the hole occurring at the time that the first communication unit detects the detected portion of the interruption request signal, with the first communication unit;

(h) processing the interruption request signal with the first communication unit, to determine whether the interruption request signal complies with predetermined criteria;

(i) transmitting an acknowledgement signal with the first communication unit when the first communication unit determines that the interruption request signal complies with the predetermined criteria, the acknowledgement signal allowing the second communication unit to interrupt the transmission;

(j) detecting the acknowledgement signal with the second communication unit; and

(k) interrupting the transmission of the first communication unit so that the second communication unit may begin transmitting information to be received by at least the first communication unit.

10. In a quasi-duplex communication system comprising a mobile communication unit, a base unit, and a telephone network interface, a method of interrupting a transmission comprising the steps of:

in the mobile communication unit;

(a) receiving an information signal;

(b) transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, the first signal comprising an audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the first signal;

(c) detecting at least a portion of an interruption request signal to determine whether the detected portion complies with a first set of predetermined criteria;

(d) extending the duration of the hole occurring at the time that the mobile communication unit detects the detected portion of the interruption request signal, when the detected portion complies with a first set of predetermined criteria, to read the interruption request signal;

(e) processing the detected portion of the interruption request signal, to determine whether the interruption request signal complies with a second set of predetermined criteria;

(f) transmitting an acknowledgement signal when the mobile communication unit determines that the interruption request signal complies with the second set of predetermined criteria, the acknowledgement signal allowing an interruption of the transmission;

(g) receiving a second signal;

(h) transmitting a second interruption request to the base unit followed by a third signal having a plurality of periodically-occurring holes of a predetermined duration, the third signal comprising an audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the third signal;

in the base unit;

(a) receiving the first signal;

(b) approximating the part of the information signal that was removed therefrom to make the holes in the first signal, to produce approximate information;

(c) filling at least some of the plurality of periodically-occurring holes with the approximate information to produce a continuous first signal;

(d) transmitting the continuous first signal to at least the telephone network interface;

(e) detecting a need for an interruption of the first signal by detecting the second signal from the telephone network interface;

(f) producing a first interruption request;

(g) transmitting the first interruption request to the mobile unit at a time when at least one of the plurality of periodically-occurring holes is occurring in the first signal, as specified by an information packet that is received by the base unit;

(h) receiving the acknowledgement signal transmitted by the mobile unit; and

(i) processing the acknowledgement signal within the base unit to determine whether to transmit;

(j) interrupting the transmission of the mobile unit when a determination is made to transmit, so that the telephone network interface may begin transmitting information through the base;

(k) receiving the second interruption request and the third signal from the mobile communication unit;

(l) approximating the parts of the information signal that were removed therefrom to make the holes in the third signal, to produce approximate information;

(m) filling the holes with the approximate information to produce a continuous third signal;

(n) transmitting the continuous third signal to at least the telephone network interface;

in the telephone network interface;

(a) receiving the continuous first signal;

(b) transmitting a second signal comprising an audio information portion to the base unit; and

(c) receiving the audio information portion of the third signal transmitted by the base unit and providing the audio information portion of the third signal to at least a user of the telephone network interface.

11. In a quasi-duplex communication system comprising a mobile communication unit, a base unit, and a telephone network interface, a method of interrupting a transmission comprising the steps of:

in the mobile communication unit;

(a) receiving an information signal;

(b) sampling the information signal at a first rate to produce a sampled information signal;

(c) storing the sampled information signal;

(d) modulating the sampled information signal at a second rate to produce a compressed audio information portion;

(e) transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, the first signal comprising the compressed audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the first signal, each hole occurring during a gap in the first signal caused by compression of the audio information portion;

(f) detecting at least a portion of an interruption request signal to determine whether the portion complies with a first set of predetermined criteria;

(g) processing the interruption request signal, to determine whether the interruption request signal complies with a second set of predetermined criteria;

(h) transmitting an acknowledgement signal when the mobile communication unit determines that the interruption request signal complies with the predetermined criteria, the acknowledgement signal allowing an interruption of the transmission;

(i) receiving a second signal;

(j) transmitting a second interruption request to the base followed by a third signal having a plurality of periodically-occurring holes of a predetermined duration, the third signal comprising a compressed audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the third signal;

in the base unit;

(a) receiving the first signal;

(b) decoding the first signal to provide a reconstructed information signal that is substantially identical to the information signal;

(d) transmitting the reconstructed information signal to at least the telephone network interface;

(e) detecting a need for an interruption of the first signal by detecting the second signal from the telephone network interface;

(f) producing a first interruption request;

(g) transmitting the first interruption request to the mobile unit at a time when at least one of the plurality of periodically-occurring holes is occurring in the first signal, as specified by an information packet that is received by the base unit;

(h) receiving the acknowledgement signal transmitted by the mobile unit; and

(i) processing the acknowledgement signal within the base to determine whether to transmit;

(j) interrupting the transmission of the mobile communication unit when a determination is made to transmit, so that the telephone network interface may begin transmitting information through the base;

(k) receiving the second interrupt request from the mobile communication unit;

(l) transmitting the audio information portion of the third signal to at least the telephone network interface;

in the telephone network interface;

(a) receiving the reconstructed information signal;

(b) transmitting a second signal comprising an audio information portion to the base; and

(c) receiving the audio information portion of the third signal sent by the base and providing the audio information portion of the third signal to at least a user of the telephone network interface.

12. The method of claim 11, further comprising the step of:

in the mobile communication unit;

(f1) extending the duration of the hole occurring at the time that the mobile communication unit detects the detected portion of the interruption request signal, when the detected portion complies with the first set of predetermined criteria, to read the interruption request signal.

13. The method of claim 11, wherein step (a) in the telephone network interface comprises the steps of:

(a1) initiating an interruption of the transmission by applying an audio signal to an audio-operated-switch; and

(a2) storing a portion of the audio signal.

14. The method of claim 12 wherein the first set of predetermined criteria of step (f) in the mobile communication unit comprises:

whether the interruption request signal is of at least a predetermined level.

15. The method of claim 12, wherein the the first set of predetermined criteria of step (f) in the mobile communication unit comprises:

whether correlation of the interruption request signal to an expected signal produces a value that is of at least a predetermined quantity.

16. In a quasi-duplex communication system comprising first and second mobile communication units, and a repeater, a method of interrupting a transmission comprising the steps of:

in the first mobile communication unit;

(a) receiving an information signal;

(b) transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, the first signal comprising an audio information portion, representing the information signal, and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the first signal;

(c) receiving at least a portion of an interruption request signal;

(d) processing the interruption request signal, to determine whether the interruption request signal complies with predetermined criteria;

(e) transmitting an acknowledgement signal when it determines that the interruption request signal complies with the predetermined criteria, the acknowledgement signal allowing an interruption of the transmission;

(f) interrupting the transmission by the first mobile communication unit so that the second mobile unit may begin transmitting signals through the repeater;

in the repeater;

(a) receiving the first signal;

(b) approximating the parts of the information signal that were removed from the holes in the first signal, to produce approximate information;

(c) filling the holes with the approximate information to produce a continuous first signal

(d) transmitting the continuous first signal to a second mobile unit;

(e) receiving the interruption request signal;

(f) transmitting the interruption request signal to the first mobile unit;

(g) receiving the acknowledgement signal to the second mobile unit; and

(h) transmitting the acknowledgement signal to the second mobile unit;

(i) receiving a second signal;

(j) approximating the information that was removed from the holes in the second signal to produce approximate information;

(k) filling the holes in the second signal with the approximate information, to produce a continuous second signal

(l) transmitting the continuous second signal to the first mobile unit;

in the second mobile communication unit;

(a) receiving the continuous first signal;

(b) transmitting an interruption request signal, at a time specified by an information packet;

(c) receiving the acknowledgement signal; and

(d) transmitting the second signal comprising a plurality of periodically-occurring holes of a predetermined duration, an audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the second signal.

17. The method of claim 16 further comprising the step of:

in the first mobile communication unit;

(c1) extending the duration of the hole occurring at the time that the first mobile communication unit receives the portion of the interruption request signal to read the interruption request signal.

18. In a quasi-duplex communication system comprising first and second mobile communication units, and a repeater, a method of interrupting a transmission comprising the steps of:

in the first mobile communication unit;

(a) receiving an information signal;

(b) sampling the information signal at a first rate to produce a sampled information signal;

(c) storing the sampled information signal;

(d) modulating the sampled information signal at a second rate to produce a compressed audio information portion;

(e) transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, the first signal comprising the compressed audio information portion, representing the information signal, and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the first signal, each hole occurring during a gap in the first signal caused by compression of the audio information portion;

(f) detecting at least a portion of an interruption request signal to determine whether the detected portion complies with a first set of predetermined criteria;

(g) processing the interruption request signal, to determine whether the interruption request signal complies with a second set of predetermined criteria;

(h) transmitting an acknowledgement signal when the first mobile unit determines that the interruption request signal complies with the predetermined criteria, the acknowledgement signal allowing an interruption of the transmission;

(i) interrupting the transmission made by the first mobile communication unit so that the second mobile unit may begin transmitting information through the repeater;

in the repeater;

(a) receiving the first signal;

(b) decoding the first signal to provide a reconstructed information signal that is substantially identical to the information signal;

(c) transmitting the reconstructed information signal to at least the second mobile communication unit;

(d) receiving the interruption request signal;

(e) transmitting the interruption request signal to at least the first mobile communication unit;

(f) receiving the acknowledgement signal transmitted by the first mobile communication unit; and

(g) transmitting the acknowledgement signal to the second mobile communication unit;

(h) receiving the second signal;

(i) transmitting the continuous second signal to the first mobile communication unit;

in the second mobile communication unit;

(a) receiving the continuous first signal;

(b) transmitting an interruption request signal, at a time specified by an information packet;

(c) receiving the acknowledgement signal; and

(d) transmitting a second signal comprising information, having a plurality of periodically-occurring holes of a predetermined duration, the second signal comprising an audio information portion and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the second signal.

19. The method of claim 18, further comprising the step of:

in the first mobile communication unit;

(f1) extending the duration of the hole occurring at the time that the first mobile communication unit receives the detected portion of the interruption request signal, the detected portion of the interruption request signal complies with the first set of predetermined criteria, to read the interruption request signal.

20. The method of claim 18, further comprising the steps of:

in the second mobile communication unit;

(a1) initiating an interruption of the transmission by applying an audio signal to a audio-operated-switch; and

(a2) storing a portion of the audio signal; and

(d) transmitting a second signal, the second signal comprising the portion of the voice signal that was stored.

21. The method of claim 19, wherein the first set of predetermined criteria of step (f) in the first mobile communication unit comprises:

whether the interruption request signal is of at least a predetermined level.

22. The method of claim 19, wherein the first step of predetermined criteria of step (f) in the first mobile communication unit comprises:

whether correlation of the interruption request signal to an expected signal produces a value that is of at least a predetermined quantity.

23. A first communication unit comprising:

means for receiving an information signal;

means for transmitting a first signal, having a plurality of periodically-occurring holes of a predetermined duration, the first signal comprising an audio information portion, representing the information signal, and at least one information packet, specifying when at least one of the plurality of periodically-occurring holes will occur in the first signal;

means for detecting at least a portion of an interruption request signal that is sent by a second communication unit, to determine whether the portion complies with a first set of predetermined criteria; and

means for interrupting transmission of the first signal, so that the second communication unit may begin transmitting information to be received by at least the first communication unit.

24. The first communication unit of claim 23 further comprising:

means for extending the duration of the hole occurring at the time that the first communication unit detects the detected portion of the interruption request signal when the detected portion of the interruption request signal complies with the first set of predetermined criteria;

means for processing the interruption request signal to determine whether the interruption request signal complies with a second set of predetermined criteria; and

means for transmitting an acknowledgement signal when the first communication unit determines that the interruption request signal complies with the second set of predetermined criteria, the acknowledgement signal allowing the second communication unit to interrupt the transmission.