Vehicular repeater

• US 4,056,779 A
• Filed: 04/05/1976
• Issued: 11/01/1977
• Est. Priority Date: 04/05/1976
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Toler, Robert Lee
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US05/673,841
• Time in Patent Office: 575 Days
• Field of Search: 343/6.8, 325/3, 325/4, 325/5, 325/6, 325/8, 325/9, 325/10, 325/16, 325/57
• US Class Current: 455/11.1
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a two-way communications system involving portable-mobile-base station transmission, a priortization method prevents interference caused by more than one mobile repeater at a single location relaying simultaneously, or by a lowband transmission skipping in from another location. When a repeater enters the system at a location, it monitors the base and portable channels, and if there is transmission activity on either channel it goes to a non-priority state. If there is no activity, a silent carrier burst is momentarily transmitted on the base channel, then the repeater goes to a non-priority state. Unless a repeater at the scene is in the priority state, each other mobile unit, upon detecting the burst, begins to repeat it out on the portable channel. When interrupted by its interrupt clock, the repeater listens for a short interval on the portable channel and if any transmission is heard, remains inhibited or in "receive" mode. The last mobile repeater to be interrupted will, of course, hear no other transmission and will return to "transmit". This unit will be established as the only unit in the priority state at that location. Any portable channel transmission will prevent base channel transmission from being repeated out on the portable channel, thus a portable-to-portable or portable-to-base transmission will have priority over base-to-portable or "skipped-in" transmission. When the unit in priority leaves or switches channels it is removed from the priority state and transmits a momentary silent carrier burst so that a new priority unit is established as before.

Claims

1. In a two-way communication system having a base station operating on a first frequency, and a plurality of vehicular installations each comprised of a mobile station operating on the first frequency, a detachable portable unit operable on a second frequency and a repeater unit for repeating out on one of said frequencies information received on the other of said frequencies, apparatus for prioritizing the repeater operation, including in combination:

first detect means for detecting received transmissions on the first frequency;

second detect means for detecting received transmissions on the second frequency;

switching means for activating one of the receive and transmit functions at the second frequency;

means coupled to the switching means for providing momentary interrupt periods in the repeater function when repeating out on the second frequency;

latching means coupled to the switching means for enabling the repeater function;

first circuit means coupled to the first and second detect means to the latching means for delatching the latching means when substantially simultaneous transmissions are received on the first and second frequencies during at least one of said interrupt periods;

delay means for relatching the latching means a predetermined period of time after the detection of received transmission;

second circuit means for disenabling repeating out on the second frequency when transmission is received on the second frequency during at least one of said interrupt periods.

2. Prioritizing apparatus as described in claim 1 and further including a time out timer for delatching the latching means after a predetermined period of uninterrupted transmission.

3. Prioritizing apparatus as described in claim 1 and further including third circuit means for delatching the latching means when the portable unit is inserted or detached from the vehicular installation.

4. Prioritizing apparatus as described in claim 2 and further including fourth circuit means for enabling a brief transmission on the first frequency if no transmissions are being received when the portable unit is inserted or detached from the vehiclular installation.

5. Prioritizing apparatus as described in claim 1 and wherein the interrupt means comprises a one shot multivibrator and a plurality of clock means for providing interrupt periods having a first spacing during a first interval after the beginning of a period of repeating out on the second frequency, followed by interrupt periods having a second spacing, the latter continuing until the end of said second frequency repeating out.

6. Prioritizing apparatus as described in claim 1 and further including third detecting means for sensing a predetermined code signal superimposed on a received second frequency transmission, and wherein the second delatching circuit means further includes means for enabling repeating out on the first frequency only when the predetermined code signal is present on the received second frequency signal.

7. A prioritized two-way communication system, the system including a base station for receiving and transmitting at a first frequency, a plurality of mobile units for receiving and transmitting at the first frequency, a portable unit associated with each one of the mobile units and adapted to receive and transmit at a second frequency when the portable unit is separated from the mobile unit, and a repeater unit coupled to each one of the mobile units, the repeater unit comprising:

circuit means for receiving signals at the second frequency;

circuit means for transmitting signals at the second frequency;

antenna means;

first switch means for selectively coupling the antenna means to one of the second frequency receiving and transmitting means;

second switch means for selectively coupling the receiving circuit means to the mobile transmitter;

clock circuitry;

first detector means responsive to the reception by the associated mobile unit of signals at the first frequency;

second detector means coupled to the receiving circuit means and responsive to the reception by the receiving circuit means of signals at the second frequency;

third detector means coupled to the receiving circuit means and responsive to a predetermined signal associated with received second frequency signals;

first logic circuitry for providing an output in response to the connection and separation of the portable unit and the mobile unit;

second logic circuitry for providing a first output at a first output terminal in response to the output of the first and second detector means, a second output at a second output terminal in response to the outputs of the second and third detector means, and a third output at a third output terminal in response to the outputs of the first, second and third detector means;

prioritizing means coupled to the output of the first logic circuitry and to the third output terminal of the second logic circuitry for enabling transmission by the mobile unit and the second frequency transmission means; and

third logic circuitry coupled to the outputs of the first logic circuitry, the first output terminal of the second logic circuitry, the clock circuitry, and the prioritizing means for activating the first switch means and the second switch means.

8. A prioritized two-way communication system according to claim 7 wherein the first switching means includes a transmit/receive relay.

9. A prioritized two-way communication system according to claim 7 wherein the second switching means includes a push-to-talk button and a relay.

10. A prioritized two-way communication system according to claim 7 wherein the clock means provides signals at predetermined times for activating the first switching means.

11. A prioritized two-way communication system according to claim 10 wherein the clock means is responsive to an output of the second logic circuitry.

12. A prioritized two-way communication system according to claim 10 wherein the clock means comprises a monostable multivibrator, two clocks and at least one logic element for providing signals having a first spacing for a predetermined period of time and signals having a second spacing after the predetermined period of time.

13. A prioritized two-way communication system according to claim 7 wherein the first detector means comprises a squelch detector circuit.

14. A prioritized two-way communication system according to claim 7 wherein the second detector means comprises a squelch detector circuit.

15. A prioritized two-way communication system according to claim 7 wherein the transmissions at the second frequency may include a predetermined signal and wherein the third detector means comprises circuit means responsive to the presence of the predetermined signal.

16. A prioritized two-way communication system according to claim 7 and further comprising socket means associated with the mobile unit for releasably receiving the portable unit therein, and the first logic circuitry includes switch means positioned for activation by the connection and separation of the portable unit and the socket of the mobile unit.

17. A prioritized two-way communication system according to claim 16 wherein the third logic circuitry comprises means for selectively activating the second switching means for one of a multiplicity of operating modes, said multiplicity including a silent transmission load.

18. A prioritized two-way communication system according to claim 17 wherein the first logic circuitry comprises latching and timing means, and is responsive to the outputs of the first detector means and the second detector means whereby the output of the first logic circuitry enables the second switching means for a period of silent transmission.

19. A prioritized two-way communication system according to claim 7 wherein the prioritizing means comprises a delay means coupled to an output of the second logic circuitry, latching means, and logic means coupled for delatching the latching means.

20. A prioritized two-way communication system according to claim 7 and further including a time out timer for disabling the first and second switching means.

21. A prioritized two-way communication system according to claim 20 wherein the time out timer is coupled between an output of the second logic circuitry and the prioritizing means and includes a timing means for delatching the latching means following a predetermined period of continued transmission from one of the mobile and repeater units.

22. A prioritized two-way communication system according to claim 7 and further including fourth detector means responsive to the first and second detector means and coupled to delatch the latching means when the outputs of the first and second detector means indicate nearly simultaneous transmission endings.

23. A prioritized two-way communication system according to claim 7 wherein the transmissions at the first frequency may include a second predetermined signal and further including first detector means comprising circuit means responsive to the presence of the second predetermined signal.