Simulcast system with minimal delay dispersion and optimal power contouring

• US 5,038,403 A
• Filed: 01/29/1991
• Issued: 08/06/1991
• Est. Priority Date: 01/08/1990
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Leitch, Clifford D.
• Primary Examiner(s): KUNTZ, CURTIS A
• Application Number:
  US07/649,134
• Time in Patent Office: 189 Days
• Field of Search: 455/16, 455/51, 455/53, 455/56, 455/58, 455/33, 375/107, 379/59-63, 370/108, 340/825.44
• US Class Current: 455/503
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A simulcast system is provided which includes a primary transmitting station surrounded by first and second rings of secondary or simulcast transmitting stations. Communication links are provided to link the primary transmitting station with the secondary stations. Respecting time delay circuits are provided in the links such that the secondary stations retransmit the information signal from the respective links at substantially the same time as the primary information signal from the primary transmitter arrives at the respective secondary transmitter.

Claims

1. A simulcast radio communication system comprising:

an information signal source for providing an information signal;

a first transmitter for transmitting said information signal to provide a transmitted information signal in a first transmission area;

a plurality of secondary transmitters, substantially peripherally situated about said first transmission area, for retransmitting said information signal into respective secondary transmission areas;

a plurality of communication links respectively coupled between said information signal source and each of said plurality of secondary transmitters, for providing said information signal to said plurality of secondary transmitters, each of said communication links exhibiting a respective propagation delay;

a plurality of time delay circuits respectively situated in series with each of said communication links;

said secondary transmitters having directional antennas coupled thereto such that said secondary transmitters radiate minimal energy toward said first transmission area, and

the time delays exhibited by said time delay circuits being selected such that said secondary transmitters retransmit said information signal received from the respective communication links at substantially the same time as said transmitted information signal from said first transmitter arrives at the respective secondary transmitter.

2. The simulcast radio communications system of claim 1 wherein said time delay circuits are located at said information signal source.

3. The simulcast radio communications system of claim 1 wherein said time delay circuits are located at said plurality of secondary transmitters.

4. The radio communications system of claim 1 wherein said information signal is a digital signal.

5. The radio communications system of claim 1 wherein said information signal is an analog signal.

6. The radio communications system of claim 1 wherein said plurality of communication links comprise a microwave links.

7. The system of claim 1 wherein said first transmitter includes a substantially omnidirectional antenna coupled thereto.

8. A simulcast radio communication system, comprising:

an information signal source for providing an information signal;

first transmitting means for transmitting said information signal into a first transmission area to provide a first transmitted signal;

at least one secondary transmitting means, situated at an approximate edge of said first transmission area, for re-transmitting a time delayed version of said information signal into secondary transmission areas that partially overlap said first transmission area; and

a communication link, coupled between said information signal source and said secondary transmitting means, having a delay means for providing said delayed version of said information signal to said secondary transmitting means approximately when said first transmitted signal arrives at said secondary transmitting means such that said first and second transmitted signals arrive within the overlap region at substantially the same time.

9. A simulcast radio communication system, comprising:

an information signal source for providing an information signal;

first transmitting means for transmitting said information signal into a first transmission area to provide a first transmitted signal;

a plurality of secondary transmitting means, situated at an approximate edge of said first transmission area, for re-transmitting a time delayed version of said information signal into secondary transmission areas that partially overlap said first transmission area to provide a second transmitted signal;

a plurality of third transmitting means, situated at an approximate edge of said second transmission area, for re-transmitting a time delayed version of said information signal into third transmission areas that partially overlap said second transmission area;

a plurality of communication links, coupled between said information signal source and at least one of said secondary transmitting means, each of said plurality of communication links having a delay means for providing said delayed version of said information signal to said secondary transmitting means approximately when said first transmitted signal arrives at said secondary transmitting means; and

a plurality of communication links, coupled between said information signal source and at least one of said third transmitting means, each of said plurality of communication links having a delay means for providing said delayed version of said information signal to said third transmitting means approximately when said second transmitted signal arrives at said third transmitting means.

10. A method for simulcasting an information signal with minimal delay dispersion, comprising the steps of:

(a) transmitting an information signal from a first transmitter into a first transmission area to provide a first transmitted signal;

(b) sending a delayed version of said information signal to at least one secondary transmitter situated approximately on the periphery of said first transmission area;

(c) transmitting said delayed version of said information signal from a second transmitter at approximately the same time that said first transmitted signal arrives at said second transmitter to provide a second transmitted signal into secondary transmission areas each having a partial overlap region with said first transmission area such that said first and second transmitted signal arrive within said overlap region at substantially the same time.

11. A simulcast radio communication system, comprising:

an information signal source for providing an information signal;

first transmitting means having an antenna system and a radiation pattern associated therewith for transmitting the information signal into a first transmission area to provide a first transmitted signal;

at least one secondary transmitting means having an antenna system and a radiation pattern associated therewith for re-transmitting a time delayed version of the information signal into secondary transmission areas that partially overlap said first transmission area; and

a communication link, coupled between the information signal source and the secondary transmitting means, having a delay means for providing the time delayed version of the information signal to the secondary transmitting means for re-transmission at a time approximately when the first transmitted signal arrives at the secondary transmitting means and such that the first transmitted signal and re-transmitted time delayed version of the information signal arrive within an overlap region comprising at least a portion of the first and second transmission areas at substantially the same time.

12. A method for simulcasting an information signal with minimal delay dispersion and optimal radiated power contouring, comprising the steps of:

transmitting the information signal from a first transmitter having an antenna system and a radiation pattern associated therewith into a first transmission area for providing a first transmitted signal;

sending a time delayed version of the information signal to at least one secondary transmitter having an antenna system and a radiation pattern associated therewith; and

re-transmitting the time delayed version of the information signal from the at least one secondary transmitter at a time approximately when the information signal arrives at the secondary transmitting means and such that the information signal and the re-transmitted time delayed version of the information signal arrive within an overlap region comprising at least a portion of the first and second transmission areas at substantially the same time.