RF receiver having frequency-hopping/direct-sequence spread spectrum signal discrimination

• US 6,320,896 B1
• Filed: 07/14/1998
• Issued: 11/20/2001
• Est. Priority Date: 07/14/1998
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Jovanovich, Alan F., Mensonides, John W., Warren, Bruce G.
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US09/115,286
• Time in Patent Office: 1,225 Days
• Field of Search: 375/130, 375/132, 375/136, 375/140, 375/147, 370/320, 370/335, 370/342
• US Class Current: 375/130
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04B 1/692 Hybrid techniques using combinations of two or more spread spectrum techniques
• CPC Class Codes: H04B 1/71 the interference being narrowband interference
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 2001/7152 with means for suppressing interference

Abstract

A receiver is provided for use in an environment in which both frequency-hopping and direct-sequence spread spectrum radio frequency (RF) signals are present. The receiver includes a receive section adapted to receive and downconvert RF input signals. A detector is coupled to the receive section, and has a plurality of parallel filter stages with each tuned for a distinct frequency band. A discriminator compares the RF energy level passing through each of the filter stages to determine whether the RF input signals are frequency-hopping or direct-sequence spread spectrum signals. A controller is adapted to control the receive section in response to the discriminator.

Claims

1. A receiving device for use in an environment in which both frequency-hopping and direct-sequence spread spectrum radio frequency (RF) signals are present, comprising:

an RF receiver for receiving RF input signals;

a detector coupled to said receiver and having a plurality of parallel stages, each one of said stages sampling an RF energy level within a distinct band of frequencies; and

a discriminator coupled to said detector for discriminating said RF input signals between frequency-hopping and direct-sequence spread spectrum signals, wherein said RF input signals comprise direct-sequence spread spectrum signals when RF energy is present in more than one of said stages, and said RF input signals comprise frequency-hopping spread spectrum signals when RF energy is present in only one of said stages.

2. The device of claim 1, further comprising a controller for controlling said receiver responsive to said discriminator.

3. The device of claim 2, further comprising a demodulator coupled to said receiver and said controller, said demodulator recovering data from said received RF input signals, said controller modifying operation of said demodulator responsive to said discriminator.

4. The device of claim 1, wherein each one of said stages comprises an integrator adapted to integrate received RF energy over a predetermined sampling time.

5. The device of claim 1, wherein each one of said stages comprises a filter tuned to one of said distinct frequency bands.

6. The device of claim 5, wherein said filter further comprises an analog filter.

7. The device of claim 5, wherein said filter further comprises a digital filter.

8. A receiver for use in an environment in which both frequency-hopping and direct-sequence spread spectrum radio frequency (RF) signals are present, comprising:

means for receiving and downconverting RF input signals; and

means for discriminating said RF input signals between frequency-hopping and direct-sequence spread spectrum signals by sampling energy level present in each one of a plurality of distinct frequency bands, wherein said RF input signals comprise direct-sequence spread spectrum signals when RF energy is present in more than one of said plurality of distinct frequency bands, and said RF input signals comprise frequency-hopping spread spectrum signals when RF energy is present in only one of said distinct frequency bands.

9. The receiver of claim 8, further comprising means for recovering data from said downconverted RF input signals in response to said discriminating means.

10. The receiver of claim 8, wherein said discriminating means comprises a plurality of parallel stages and a detector coupled to said stages, each one of said stages being tuned for a distinct frequency band, said detector being adapted to sample an RF energy level passing through said stages and provide a signal indicating whether said RF input signals are frequency-hopping or direct-sequence spread spectrum signals.

11. The receiver of claim 10, wherein each one of said stages comprises a filter tuned to one of said distinct frequency bands.

12. The receiver of claim 10, wherein each one of said stages comprises an integrator adapted to integrate received RF energy over a predetermined time.

13. The receiver of claim 10, wherein each one of said stages comprises an analog filter.

14. The receiver of claim 10, wherein each one of said stages comprises a digital filter.

15. The receiver of claim 8, wherein said data recovering means comprises a demodulator coupled to said receiving means.

16. In an environment in which both frequency-hopping and direct-sequence spread spectrum radio frequency (RF) signals are present, a method for receiving data comprises:

receiving and downconverting RF input signals; and

discriminating said RF input signals between frequency-hopping and direct-sequence spread spectrum signals by sampling energy level present in each one of a plurality of distinct frequency bands, wherein said RF input signals are direct-sequence spread spectrum signals when RF energy is present in more than one of said plurality of distinct frequency bands, and said RF input signals are frequency-hopping spread spectrum signals when RF energy is present in only one of said plurality of distinct frequency bands.

17. The method of claim 16, further comprising recovering data from said downconverted RF input signals in response to said discriminating step.

18. The method of claim 16, wherein said discriminating step comprises providing a signal indicating whether said RF input signals are frequency-hopping or direct-sequence spread spectrum signals.

19. The method of claim 16, wherein said discriminating step comprises integrating received RF energy over a predetermined sampling time.