Wireless network circuits, systems, and methods for frequency hopping with reduced packet interference

• US 6,643,278 B1
• Filed: 12/28/1999
• Issued: 11/04/2003
• Est. Priority Date: 03/23/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Panasik, Carl M., Siep, Thomas M.
• Primary Examiner(s): TON, DANG T
• Application Number:
  US09/473,337
• Time in Patent Office: 1,407 Days
• Field of Search: 370/330, 370/480, 370/342, 370/441, 370/442, 370/241, 370/252, 370/254, 370/389, 370/392, 370/465, 370/394, 370/344, 370/345, 375/130, 375/131, 375/132-134, 380/49, 380/9, 380/48, 380/59, 455/422, 455/436
• US Class Current: 370/330
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 2001/7154 with means for preventing interference
• CPC Class Codes: H04B 2001/71563 Acquisition

Abstract

A method (10) for determining a frequency hopping sequence for a newly-entering network. The method comprises the step of scanning (16) a plurality of frequency channels. For each of the plurality of frequency channels, the scanning step comprises detecting whether a signal (18, 22) exists on the channel and recording information (20, 24) corresponding to each channel on which a signal is detected. Finally, and responsive to the recorded information, the method forms (30) the frequency hopping sequence.

Claims

1. A method for determining a frequency hopping sequence for a newly-entering network, comprising the steps of:

scanning a plurality of frequency channels, comprising the steps of;

detecting whether a signal exists on each frequency channel; and

recording information corresponding to each frequency channel on which said signal is detected; and

responsive to the information, forming the frequency hopping sequence.

2. The method of claim 1 wherein the detecting step comprises detecting whether a packet signal exists on each channel on which the signal is detected.

3. The method of claim 2 wherein the packet signal exists on the channel in response to a packet communicated by an incumbent network along the channel on which the signal is detected.

4. The method of claim 3:

wherein the detecting step comprises detecting an indication of a hopping sequence for the incumbent network and corresponding to the packet communicated by the incumbent network; and

wherein the recording step comprises recording the indication.

5. The method of claim 3 wherein the recording step comprises:

recording an identifier of the channel on which the signal is detected; and

recording a time indication corresponding to when the signal is detected.

6. The method of claim 3 wherein the detecting step further comprises detecting whether a fixed interference signal exists on the channel on which the signal is detected.

7. The method of claim 6 wherein the recording step comprises recording an identifier of the channel on which the fixed interference signal is detected.

8. The method of claim 7 wherein each of the steps of detecting whether a packet signal exists and detecting whether the fixed interference signal exists is responsive to a bandwidth of the signal on the channel.

9. The method of claim 7 wherein each of the steps of detecting whether a packet signal exists and detecting whether the fixed interference signal exists is responsive to a scan of a plurality of sub-channels of the channel.

10. The method of claim 7:

wherein each packet communicated by the incumbent network has a known maximum duration; and

wherein the step of detecting whether the fixed interference signal exists is responsive to scanning each of the plurality of frequency channels for a period of time which exceeds the maximum duration.

11. The method of claim 2:

wherein the detecting step comprises detecting an indication of a hopping sequence for an incumbent network and corresponding to the packet signal communicated by the incumbent network;

wherein the recording step comprises recording an indication; and

wherein the recording step comprises;

recording an identifier of the channel on which the signal is detected; and

recording a time indication corresponding to when the signal is detected.

12. The method of claim 2 wherein the detecting step further comprises detecting whether a fixed interference signal exists on the channel on which the signal is detected.

13. The method of claim 12 wherein the recording step comprises recording an identifier of the channel on which the fixed interference signal is detected.

14. The method of claim 2 wherein the packet signal exists on the channel in response to one of either:

a packet communicated by the incumbent network along the channel on which the signal is detected; and

a packet communicated by the incumbent network along a channel adjacent to the channel on which the signal is detected.

15. The method of claim 1 wherein the detecting step comprises further detecting whether a fixed interference signal exists on the channel on which the signal is detected.

16. The method of claim 15 wherein the recording step comprises recording an identifier of the channel on which the fixed interference signal is detected.

17. The method of claim 1:

wherein the detecting step detects packet signals in response to packets communicated along the plurality of frequency channels by an incumbent network having an incumbent network hopping sequence; and

wherein the step of forming the frequency hopping sequence for the newly-entering network comprises forming the hopping sequence equal to the incumbent network hopping sequence.

18. The method of claim 17 and further comprising the steps of:

waiting until the incumbent network transmits a first packet along a first channel corresponding to a first channel in the incumbent network hopping sequence; and

after the waiting step, transmitting a packet with the newly-entering network according to the hopping sequence for the newly-entering network.

19. The method of claim 1:

wherein the detecting step detects packet signals in response to packets communicated along the plurality of frequency channels by an incumbent network having an incumbent network hopping sequence;

wherein the detecting step detects signals in response to fixed interference along at least one of the plurality of frequency channels; and

wherein the step of forming the frequency hopping sequence for the newly-entering network comprises;

forming a first hopping sequence equal to the incumbent network hopping sequence; and

forming the frequency hopping sequence for the newly-entering network by modifying the first hopping sequence to not include any one of the plurality of channels along which fixed interference is detected.

20. The method of claim 19 wherein the modifying step comprises selecting an alternative channel from a rotation of channels such that the selected alternative channel is used in the frequency hopping sequence for the newly-entering network in place of one of the plurality of channels along which fixed interference is detected.

21. The method of claim 20 wherein the rotation of channels comprise a plurality of interference-free channels in which the detecting step has not detected a signal existing on each of the interference-free channels.

22. The method of claim 1:

wherein the scanning step is operable to identify packet signals in response to a hopping sequence of an incumbent network;

wherein the hopping sequence of the incumbent network consists of an integer number N of different channels along which the incumbent network may transmit packets;

wherein the step of scanning a plurality of frequency channels comprises scanning each of the plurality of frequency channels multiple times; and

wherein for each of the multiple times each of the plurality of frequency channels is scanned for a period no greater than a ratio of one over the integer N.

23. The method of claim 1:

wherein the scanning step is operable to identify packet signals in response to a hopping sequence of an incumbent network;

wherein the hopping sequence of the incumbent network consists of an integer number M of sequence channels over which the incumbent network is operable to transmit packets before repeating the hopping sequence of the incumbent network; and

wherein the step of scanning a plurality of frequency channels comprises scanning each of the plurality of frequency channels for a period at least equal to a time required by the incumbent network to transmit packets along the integer number M of sequence channels.

24. A method for determining a frequency hopping sequence for a newly-entering network, comprising the steps of:

scanning a plurality of frequency channels, comprising the steps of;

detecting whether a signal exists on each frequency channel; and

recording information corresponding to each frequency channel on which said signal is detected; and

responsive to the information and without negotiating with a preexisting user, forming the frequency hopping sequence.

25. A method for determining a frequency hopping sequence for a newly-entering network, comprising the steps of:

scanning a plurality of frequency channels, comprising the steps of;

detecting whether a signal exists on each frequency channel; and

recording information corresponding to each frequency channel on which said signal is detected; and

responsive to the information and without negotiation, forming the frequency hopping sequence on unused frequency channels.