RF communications system operable in the presence of a repetitive interference source and related methods

• US 6,006,071 A
• Filed: 01/12/1998
• Issued: 12/21/1999
• Est. Priority Date: 01/12/1998
• Status: Expired due to Term

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Corporation (Renesas Electronics Corporation)
• Inventors: Roberts, Richard D., Nelson, George R.
• Primary Examiner(s): TROST IV, WILLIAM GEORGE
• Application Number:
  US09/006,071
• Time in Patent Office: 708 Days
• Field of Search: 455/63, 455/66, 455/67.1, 455/67.3, 455/67.5, 455/88, 455/295-296, 455/298-299, 455/402-403, 375/346, 219/715-716, 381/311, 381/71.3
• US Class Current: 455/63.1
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10

Abstract

An RF communication system is for operating in the presence of a repetitive RF interference source powered from an Alternating Current (AC) power line. The system uses redundant transmission synchronized to the power line to ensure accurate reception by at least one second device. The RF communication system includes a first device powered from an AC power line which also powers the repetitive RF interference source. The first device, in turn, preferably includes an RF transmitter for transmitting in a frequency band of the repetitive RF interference source, a power line sensor, and a data transmit controller. The data transmit controller generates a plurality of data packets with each data packet including an error detecting portion. The data transmit controller also operates the RF transmitter to produce repetitive first and second transmissions of a same data packet responsive to the power line sensor. Accordingly, at least one of the first and second transmissions occurs during an OFF period of the repetitive RF interference source. The second device also preferably includes a data receive controller for receiving the repetitive first and second transmissions of same data packets and selecting one based upon the error detecting portions thereof to thereby avoid interference from the repetitive RF interference source.

Claims

1. A radio frequency (RF) communication system or operating in the presence of a repetitive RF interference source powered from an Alternating Current (AC) power line, the repetitive RF interference source having repetitive ON and OFF periods based upon the AC power line, the RF communication system comprising:

a first device powered from an AC power line which also powers the repetitive RF interference source, said first device comprising

an RF transmitter for transmitting in a frequency band of the repetitive RF interference source,

a power line sensor, and

data transmit control means for generating a plurality of data packets with each data packet including an error detecting portion, and for operating said RF transmitter to produce repetitive first and second transmissions of a same data packet responsive to said power line sensor so that at least one of the first and second transmissions occurs during an OFF period of the repetitive RF interference source; and

at least one second device comprising

an RF receiver for receiving in the frequency band of the repetitive RF interference source, and

data receive control means for receiving the repetitive first and second transmissions of same data packets and selecting one based upon the error detecting portions thereof to thereby avoid interference from the repetitive RF interference source.

2. An RF communication system according to claim 1 wherein said data transmit control means comprises means for generating each data packet and error detecting portion to be less than or equal to one-half a period of the AC power line.

3. An RF communication system according to claim 1 wherein said first device and said at least one second device establish only a one-way communication channel therebetween.

4. An RF communication system according to claim 1 wherein said first device further comprises audio input means for accepting at least one audio signal for transmission;

and wherein said at least one second device further comprises at least one speaker for reproducing the at least one audio signal.

5. An RF communication system wherein the RF claim 1 wherein the RF transmitter and RF receiver operate in a frequency range of about 2.45 GHz.

6. An RF communication system according to claim 1 wherein said data control means includes Cyclic Redundancy Check (CRC) means for generating a CRC checksum error detecting portion for each data packet.

7. An RF communication system according to claim 1 wherein said RF transmitter is a spread spectrum transmitter;

and wherein said RF receiver is a spectrum receiver.

8. An RF communication system according to claim 1 wherein the AC power line comprises a plurality of power phases;

and wherein said first device further comprises phase selecting means for selecting operation for one of the plurality of power phases.

9. An RF communication system according to claim 8 wherein said at least one second device further comprises indicator means for indicating correct receipt of a data packet to enable a user to select operation of said first device for one of the AC power line phases.

10. An RF communication system according to claim 8 wherein said phase selecting means comprise delay adding means for adding a predetermined delay before transmitting each data packet based upon the respective selected power phase.

11. An RF communication system according to claim 1 wherein said power line sensor comprises a comparator for generating a square wave responsive to sensing the AC power line and an edge detector coupled thereto for triggering transmission based upon the AC power line.

12. A radio frequency (RF) communication system for operating in the presence of a repetitive RF interference source powered from an Alternating Current (AC) power line, the repetitive RF interference source having repetitive ON and OFF periods based upon the AC power line, the RF communication system comprising:

a first device powered from an AC power line which also powers the repetitive RF interference source, said first device comprising

audio input means for accepting at least one audio signal for transmission,

an RF transmitter for transmitting in a frequency band of the repetitive RF interference source,

a power line sensor, and

data transmit control means for generating a plurality of data packets from said at least one audio input means with each data packet including an error detecting portion, and for operating said RF transmitter to produce repetitive first and second transmissions of a same data packet responsive to said power line sensor so that at least one of the first and second transmissions occurs during an OFF period of the repetitive RF interference source; and

at least one second device comprising

an RF receiver for receiving in the frequency band of the repetitive RF interference source,

data receive control means for receiving the repetitive first and second transmissions of same data packets and selecting one based upon the error detecting portions thereof to thereby avoid interference from the repetitive RF interference source, and

at least one audio speaker operatively connected to said data receiver control means for reproducing the at least one audio signal.

13. An RF communication system according to claim 12 wherein said data transmit control means comprises means for generating each data packet and error detecting portion to be less than or equal to one-half a period of the AC power line.

14. An RF communication system according to claim 12 wherein said first device and said at least one second device establish only a one-way communication channel therebetween.

15. An RF communication system according to claim 12 wherein the RF transmitter and RF receiver operate in a frequency range of about 2.45 GHz.

16. An RF communication system according to claim 12 wherein said data control means includes Cyclic Redundancy Check (CRC) means for generating a CRC checksum error detecting portion for each data packet.

17. An RF communication system according to claim 12 wherein said RF transmitter is a spread spectrum transmitter;

and wherein said RF receiver is a spread spectrum receiver.

18. An RF communication system according to claim 12 wherein the AC power line comprises a plurality of power phases;

and wherein said first device further comprises phase selecting means for selecting operation for one of the plurality of power phases.

19. An RF communication system according to claim 18 wherein said at least one second device further comprises indicator means for indicating correct receipt of a data packet to enable a user to select operation of said first device for one of the AC power line phases.

20. An RF communication system according to claim 18 wherein said phase selecting means comprise delay adding means for adding a predetermined delay before transmitting each data packet based upon the respective selected power phase.

21. An RF communication system according to claim 12 wherein said power line sensor comprises a comparator for generating a square wave responsive to sensing the AC power line and an edge detector coupled thereto for triggering transmission based upon the AC power line.

22. A radio frequency (RF) communication system for operating in the presence of a repetitive RF interference source powered from an Alternating Current (AC) power line having a plurality of phases, the repetitive RF interference source having repetitive ON and OFF periods based upon the AC power line, the RF communication system comprising:

a first device powered from an AC power line which also powers the repetitive RF interference source, said first device comprising

an RF transmitter for transmitting in a frequency band of the repetitive RF interference source,

a power line sensor,

data transmit control means for generating a plurality of data packets with each data packet including an error detecting portion, and for operating said RF transmitter to produce repetitive first and second transmissions of a same data packet responsive to said power line sensor so that at least one of the first and second transmissions occur during an OFF period of the repetitive RF interference source, and

phase selecting means for selecting operation of the data transmit control means for one of the plurality of power phases; and

at least one second device comprising

an RF receiver for receiving in the frequency band of the repetitive RF interference source, and

data receive control means for receiving the at least one transmission to thereby avoid interference from the repetitive RF interference source.

23. An RF communication system according to claim 22 wherein said at least one second device further comprises indicator means for indicating correct receipt of a data packet to enable a user to select operation of said first device for one of the AC power line phases.

24. An RF communication system according to claim 22 wherein said phase selecting means comprise delay adding means for adding a predetermined delay before transmitting each data packet based upon the respective selected power phase.

25. An RF communication system according to claim 22 wherein said data receive control means comprises means for receiving the repetitive first and second transmissions of same data packets and selecting one based upon the error detecting portions thereof to thereby avoid interference from the repetitive RF interference source.

26. An RF communication system according to claim 22 wherein said data transmit control means comprises means for generating each data packet and error detecting portion to be less than or equal to one-half a period of the AC power line.

27. An RF communication system according to claim 22 wherein said first device and said at least one second device establish only a one-way communication channel therebetween.

28. An RF communication system according to claim 22 wherein said first device further comprises audio input means for accepting at least one audio signal for transmission;

and wherein said at least one second device further comprises at least one speaker for reproducing the at least one audio signal.

29. An RF communication system according to claim 22 wherein the RF transmitter and RF receiver operate in a frequency range of about 2.45 GHz.

30. An RF communication system according to claim 22 wherein said RF transmitter is a spread spectrum transmitter;

and wherein said RF receiver is a spectrum receiver.

31. A method for operating a radio frequency (RF) communication system in the presence of a repetitive RF interference source powered from an Alternating Current (AC) power line, the repetitive RF interference source having repetitive ON and OFF periods based upon the AC power line, the RF communication system comprising a first device powered from an AC power line which also powers the repetitive RF interference source and at least one second device, the first device comprising an RF transmitter for transmitting in a frequency band of the repetitive RF interference, the at least one second device comprising an RF receiver for receiving in the frequency band of the repetitive RF interference source, the method comprising the steps of:

sensing the AC power line;

generating a plurality of data packets with each data packet including an error detecting portion, and for operating the RF transmitter to produce repetitive first and second transmissions of a same data packet responsive to the AC power line so that at least one of the first and second transmissions occurs during an OFF period of the repetitive RF interference source; and

receiving at the RF receiver the repetitive first and second transmissions of same data packets and selecting one based upon the error detecting portions thereof to thereby avoid interference from the repetitive RF interference source.

32. A method according to claim 31 wherein the step of generating the plurality of data packets comprises generating each data packet and error detecting portion to be less than or equal to one-half a period of the AC power line.

33. A method according to claim 31 further comprising the step of establishing only a one-way communication channel from the first device to the at least one second device.

34. A method according to claim 31 further comprising the step of accepting at least one audio signal for transmission.

35. A method according to claim 31 further comprising step of operating the RF transmitter and RF receiver in a frequency range of about 2.45 GHz.

36. A method according to claim 31 wherein the step of including an error detection portion comprises generating a CRC checksum error detecting portion for each data packet.

37. A method according to claim 31 further comprising the step of operating the RF transmitter for spread spectrum.

38. A method according to claim 31 wherein the AC power line comprises a plurality of power phases;

and further comprising the step of selecting operation of the first device for one of the plurality of power phases.

39. A method according to claim 38 further comprising the step of indicating at the at least one second device correct receipt of a data packet to enable a user to select operation of the first device for one of the AC power line phases.

40. A method according to claim 38 wherein the step of selecting comprises adding a predetermined delay before transmitting each data packet based upon the repetitive selected power line phase.