Multiple subcarrier communication system

• US 6,088,577 A
• Filed: 01/13/1999
• Issued: 07/11/2000
• Est. Priority Date: 01/13/1999
• Status: Expired due to Fees

• Current Assignee: Clariti Telecommunications International Ltd. (Integrated Data Corp.)
• Original Assignee: Clariti Telecommunications International Ltd. (Integrated Data Corp.)
• Inventors: Wu, Albert, Wu, William, Yang, Michael Y.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): VINCENT, DAVID ROBERT
• Application Number:
  US09/229,536
• Time in Patent Office: 545 Days
• Field of Search: 455/38.1, 455/45, 455/186.1, 455/72, 455/102-3, 455/435-444, 340/825.44, 375/260, 375/216
• US Class Current: 340/7.57
• CPC Class Codes: H04H 20/34 using an out-of-band subcarrier signal
• CPC Class Codes: H04H 20/95 characterised by a specific format, e.g. an encoded audio stream
• CPC Class Codes: H04H 2201/13 radio data system/radio broadcast data system [RDS/RBDS]
• CPC Class Codes: H04H 2201/70 characterised in that receivers can be addressed
• CPC Class Codes: H04H 60/14 Arrangements for conditional access to broadcast information or to broadcast-related services
• CPC Class Codes: H04W 88/023 with message or information receiving capability
• CPC Class Codes: H04W 88/185 Selective call encoders for paging networks, e.g. paging centre devices

Abstract

The present invention is a digital FM voice paging system which uses digital signal processing (including D/A conversion and data compression) to transmit voice pager data over existing FM broadcast subcarriers.

Claims

1. The paging system of claim 1 wherein said means for transmitting said identification signal further comprises:

means for converting said identification signal into an encoded identification signal having a first format, and,

means for transmitting a broadcast identification signal modulated by said encoded identification signal.

2. The method of claim 1, wherein

the receiver is a member of a plurality of receivers and the identification signal selectively identifies the receiver, and

the message signal corresponds to the identification signal and enables selective reception of the message signal by the receiver.

3. The method of claim 1, wherein

the step of modulating an identification signal comprises modulating the identification signal onto a Radio Data System subcarrier of an FM communication channel, and

the step of modulating a message signal comprises modulating the message signal onto a Subsidiary Communications Authorization subcarrier of an FM communication channel.

4. The paging system of claim 1 wherein said means for receiving is an FM receiver.

5. The paging system of claim 1 wherein at least one of said subcarriers is a Sub-Carrier Administration (SCA) based subcarrier.

6. A paging system using subcarriers within a commercial FM channel bandwidth comprising:

(1) transmitter means comprising;

means for generating an identification signal;

means for converting said identification signal into an encoded identification signal having a first format;

means for transmitting a broadcast identification signal modulated by said encoded identification signal;

an analog voice signal;

means for processing said analog voice signal to produce a compressed digital message signal;

means for converting said message signal into an encoded message signal having a second format;

means for transmitting a broadcast message signal modulated by said encoded message signal; and

,

(2) receiver means comprising;

means for receiving said broadcast identification signal to produce a received identification signal;

means for decoding said received identification signal to produce an alert signal;

means for receiving said broadcast message signal, said means responsive to said alert signal to enable receipt of said broadcast message signal to produce a received message signal;

means for decoding said received message signal to produce a digital, compressed received message signal;

means for storing at least one of said digital, compressed received message signals;

an output enable signal;

means for processing said stored digital, compressed received message signal, said means responsive to said output enable signal to produce an analog, voice signal; and

,

means for outputting said voice signal.

7. The method of claim 6, wherein

the broadcast signal is received by a receiver being a member of a plurality of receivers for selectively receiving the broadcast signal and the identification signal selectively identifies the receiver, and

the message signal is selectively recovered in response to the identification.

8. The method of claim 6, wherein

the step of recovering the identification signal comprises demodulating a Radio Data System subcarrier, and

the step of recovering the message signal comprises demodulating a Subsidiary Communications Authorization subcarrier.

9. A method of communicating data at a high data rate using at least one subcarrier within an FM channel bandwidth, comprising the steps of:

receiving an identification signal;

receiving an analog voice signal;

digitally encoding said signals to transform said signals into digitally compressed signals in accordance with at least one FM subcarrier format;

transmitting said encoded signals via at least one FM subcarrier;

receiving said encoded signals;

storing said received signals;

retrieving said stored signals; and

,

outputting said stored signals.

10. The method of communicating of claim 9 where said encoding step includes the addtional steps of:

combining said identification and analog signals to form a combined message signal; and

,

converting said combined message signal into a digital, compressed message signal.

11. The method of communicating of claim 10 where said transmitting step includes the additional steps of:

providing a first signal having a predetermined frequency to define said subcarrier;

modulating said subcarrier with said digital, compressed message signal;

providing a second signal having a predetermined frequency defining a carrier signal for a said FM channel; and

,

frequency modulating said modulated subcarrier on said carrier signal, said frequency modulated carrier signal being coupled to an antenna for broadcast to a plurality of mobile receiving systems.

12. The method of communicating of claim 11 where said receiving step includes the additional steps of:

receiving said frequency modulated carrier signal by a mobile receiving system in response to said identification signal;

demodulating said received frequency modulated carrier signal to recover said modulated subcarrier; and

,

demodulating said subcarrier to recover said digital, compressed message signal.

13. The method of communicating of claim 12 where said retrieving step includes the additional step of:

converting said retrieved signals from a digital, compressed form into an analog message signal.

14. The transmitted signal of claim 13, wherein

the receiver is a member of a plurality of receivers and the identification signal selectively identifies the receiver, and

the message signal corresponds to the identification signal and enables selective reception of the message signal by the receiver.

15. The transmitted signal of claim 14, further comprising a primary broadcast carrier modulated with primary station signal information, and wherein the first subcarrier is a Radio Data System subcarrier of an FM communication channel.

16. The method of communicating of claim 15 where said receiving step includes the additional steps of:

receiving said frequency modulated carrier signal by a mobile receiving system in response to said identification signal;

demodulating said received frequency modulated carrier signal to recover said modulated first and second subcarriers;

demodulating said first subcarriers to recover said identification signal; and

,

demodulating said second subcarrier in response to said identification signal to recover said digital, compressed message signal.

17. The method of communicating of claim 16 where said retrieving step includes the additional step of:

converting said retrieved signals from a digital, compressed form into an analog message signal.

18. The transmitted signal of claim 14, wherein the primary broadcast carrier is an FM channel broadcast carrier.

19. A paging transmitter for transmitting messages to a plurality of pagers over a communication channel, the transmitter comprising:

a modulator for modulating an identification signal for a pager of the plurality of pagers onto a first subcarrier of a communication channel to form a first transmit signal;

a modulator for modulating a message signal for selective reception by the pager onto a second subcarrier of the communication channel to form a second transmit signal; and

a transmitter for transmitting the first transmit signal and the second transmit signal in the communication channel.

20. The method of claim 19, wherein the first subcarrier is a Radio Data System subcarrier of an FM communication channel.

21. The method of claim 19, wherein the second subcarrier is a Subsidiary Communications Authorization subcarrier of an FM communication channel.

22. The method of claim 20, wherein the second subcarrier is a Subsidiary Communications Authorization subcarrier of an FM communication channel.

23. The method of claim 21, wherein the first subcarrier is a Subsidiary Communications Authorization subcarrier of an FM communication channel.

24. A pager for receiving a message transmitted over a communication channel to a pager, the pager comprising:

an antenna for receiving a broadcast signal in a communication channel; and

a demodulator coupled to the antenna for recovering an identification signal indicative of the pager carried on a first subcarrier in the broadcast signal and for recovering a message signal carried on a second subcarrier in the broadcast signal in response to the identification signal.

25. The pager of claim 24, wherein the first subcarrier is a Radio Data System subcarrier.

26. The pager of claim 24, wherein the second subcarrier is a Subsidiary Communications Authorization subcarrier.

27. The pager of claim 25, wherein the second subcarrier is a Subsidiary Communications Authorization subcarrier.

28. The pager of claim 26, wherein the first subcarrier is a Subsidiary Communications Authorization subcarrier.

29. The pager of claim 24, further comprising:

a decoder for producing an alert signal in response to the identification signal; and

circuitry for enabling the pager to recover the message signal based on the alert signal.

30. The pager of claim 29, further comprising:

circuitry for outputting to a speaker in the pager a voice signal represented by the message signal.