FREQUENCY-HOPPING SCHEME

• US 20100260232A1
• Filed: 04/13/2010
• Published: 10/14/2010
• Est. Priority Date: 04/13/2009
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Batra, Anuj, Roh, June Chul
• Granted Patent: US 8,374,214 B2
• Time in Patent Office: Days
• US Class Current: 375/133
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns

Abstract

A method comprises generating, by logic, a random number. The method also comprises determining a next frequency in said sequence using the random number and one or more of a minimum separation, a channel number, and a number of channels. The method further comprises hopping to the next frequency.

Claims

1. A method of producing a frequency hopping sequence, comprising:

generating, by logic, a random number;

determining a next frequency in said sequence using said random number and one or more of a minimum separation, a channel number, and a number of channels; and

hopping to said next frequency.

2. The method of claim 1, wherein determining the next frequency comprises determining a sum of said random number, said minimum separation, and said channel number.

3. The method of claim 2, wherein determining the next frequency further comprises performing a modulo function with said sum and said number of channels.

4. The method of claim 1, further comprising generating multiple random numbers to help determine multiple frequencies in said sequence, said multiple random numbers evenly distributed over a reduced set.

5. The method of claim 4, wherein said reduced set comprises a range that is determined using said number of channels and said minimum separation.

6. The method of claim 5, wherein said range is determined using the equation N_reduced=N_ch−

2N_sep+1, wherein N_reduced is the reduced number of possible channel numbers that can be used at a time (k+1), N_ch is said number of channels and N_sep is said minimum separation.

7. The method of claim 1, wherein generating said random number comprises:

selecting a secondary random number from a set, a range of said set determined using 2^m, wherein m is a number of shift registers tapped in a linear feedback shift register; and

generating said random number using said secondary random number, a time index value, and a number of possible channel numbers.

8. The method of claim 1, wherein generating said random number comprises using the equation z(k+1)=[(y(k+1)+k)mod N_reduced], where z(k+1) is the random number, y(k+1) is a secondary random number determined using a linear feedback shift register, k is a time index value, and N_reduced comprises N_ch−

2N_sep+1, wherein N_ch comprises said number of channels and N_sep comprises the minimum separation.

9. The method of claim 1, wherein generating said random number comprises performing a modulo function between a secondary random number and a number of possible channel numbers.

10. The method of claim 1, wherein generating said random number comprises:

selecting a secondary random number from a set, a range of said set determined using 2ⁿ, wherein n corresponds to a number of states of a linear feedback shift register; and

generating said random number using the secondary random number and a number of possible channel numbers.

11. The method of claim 1, wherein generating said random number comprises:

selecting a secondary random number y(k+1), wherein y(k+1) is among the set {0, 1, . . . , N−

1} and comprises an output of an n-state linear feedback shift register, wherein N=2ⁿ, wherein N is greater than N_reduced, wherein N_reduced=N_ch−

2N_sep+1, and wherein N_ch is said number of channels and N_sep is said minimum separation; and

generating said random number using the secondary random number according to the equation z(k+1)=y(k+1)mod N_reduced.

12. The method of claim 1, wherein generating said random number comprises using a linear congruential generator (LCG).

13. The method of claim 1, wherein generating, determining and hopping comprise generating, determining, and hopping in compliance with the IEEE 802.15.6 protocol.

14. A method, comprising:

sending or receiving data using a center frequency associated with a first channel number;

determining a second channel number, wherein the second channel number is at least a predetermined number of channels away from said first channel number, and wherein the determination of the second channel number is in accordance with a uniform distribution scheme over a set of possible channel numbers;

hopping from said center frequency associated with the first channel number to another frequency associated with the second channel number; and

sending or receiving data using said another center frequency associated with the second channel number.

15. The method of claim 14, wherein said predetermined number of channels comprises a coherence bandwidth or a fraction of said coherence bandwidth.

16. The method of claim 14, wherein determining the second channel number comprises determining a random number, said random number is distributed over a reduced set of possible numbers.

17. The method of claim 16, wherein said random number is uniformly distributed over the reduced set of possible numbers.

18. The method of claim 14, wherein determining the second channel number comprises determining a random number, summing said random number with a channel number and a minimum separation to produce a sum, and performing a modulo function between said sum and a total number of available channels in a frequency band.

19. The method of claim 14, further comprising:

selecting a secondary random number from a set, a range of said set determined using 2^m, wherein m is a number of a subset of shift registers in a linear feedback shift register;

generating a random number using said secondary random number, a time index value, and a number of possible channel numbers; and

using said random number to determine the second channel number.

20. The method of claim 14, wherein determining the second channel number comprises generating and using a random number, and wherein generating said random number comprises using the equation z(k+1)=[(y(k+1)+k)mod N_reduced], where z(k+1) is the random number, y(k+1) is a secondary random number determined using a linear feedback shift register, k is a time index value, and N_reduced comprises N_ch−

2N_sep+1, wherein N_ch comprises a number of channels and N_sep comprises a minimum separation.

21. The method of claim 14, wherein determining the second channel number comprises generating a random number, and wherein generating said random number comprises:

selecting a secondary random number from a set, a range of said set determined using 2ⁿ, wherein n corresponds to a number of states of a linear feedback shift register; and

generating said random number using the secondary random number and a number of possible channel numbers.

22. The method of claim 14, wherein determining the second channel number comprises generating a random number, and wherein generating said random number comprises:

selecting a secondary random number y(k+1), wherein y(k+1) is selected from among the set {0, 1, . . . , N−

1}, comprises an output of an n-state linear feedback shift register, wherein N=2ⁿ, wherein N is greater than N_reduced, wherein N_reduced=N_ch−

2N_sep+1, and wherein N_ch is a number of channels and N_sep is a minimum separation; and

generating said random number using the secondary random number according to the equation z(k+1)=y(k+1)mod N_reduced.

23. The method of claim 14, wherein determining the second channel number comprises generating a random number, and wherein generating said random number comprises using a linear congruential generator (LCG).

24. The method of claim 14, wherein each of the steps of sending or receiving data using the center frequency, determining, hopping, and sending or receiving data using the another center frequency comprises complying with the IEEE 802.15.6 protocol.

25. A system, comprising:

logic; and

communication logic coupled to the logic;

wherein the logic causes the communication logic to hop among multiple center frequencies and further causes the communication logic to transmit or receive data using said multiple center frequencies;

wherein, with each hop, the logic selects a target center frequency that is separated from a previous center frequency by at least a minimum separation.

26. The system of claim 25, wherein said minimum separation comprises a coherence bandwidth or a fraction of said coherence bandwidth.

27. The system of claim 25, wherein the logic selects said target frequency using a random number, and wherein said random number is distributed over a reduced set of possible numbers.

28. The system of claim 27, wherein said random number is evenly distributed over the reduced set of possible numbers.

29. The system of claim 25, wherein the logic determines the target frequency using a random number;

wherein the logic sums with random number with a channel number and a minimum separation to produce a sum, and wherein the logic performs a modulo function between said sum and a total number of available channels in a frequency band.

30. The system of claim 25, wherein:

the logic selects a secondary random number from a set, a range of said set determined using 2^m, wherein m is a number of shift registers tapped in a linear feedback shift register;

the logic generates a random number using said secondary random number, a time index value, and a number of possible channel numbers; and

the logic uses said random number to determine the target center frequency.

31. The system of claim 25, wherein the logic determines the target center frequency using a random number, and wherein the logic determines the random number using the equation z(k+1)=[(y(k+1)+k)mod N_reduced], where z(k+1) is the random number, y(k+1) is a secondary random number determined using a linear feedback shift register, k is a time index value, and N_reduced comprises N_ch−

2N_sep+1, wherein N_ch comprises a number of channels and N_sep comprises a minimum separation.

32. The system of claim 25, wherein the logic determines the target center frequency using a random number, and wherein the logic:

selects a secondary random number from a set, a range of said set determined using 2ⁿ, wherein n corresponds to a number of states of a linear feedback shift register; and

generates said random number using the secondary random number and a number of possible channel numbers.

33. The system of claim 25, wherein the logic determines the target center frequency using a random number, and wherein, to generate the random number, the logic:

selects a secondary random number y(k+1), wherein y(k+1) is selected from among the set {0, 1, . . . , N−

1} and comprises an output of an n-state linear feedback shift register, wherein N=2ⁿ, wherein N is greater than N_reduced, and N_reduced=N_ch−

2N_sep+1, and wherein N_ch is a number of channels and N_sep is a minimum separation; and

generates said random number using the secondary random number according to the equation z(k+1)=y(k+1)mod N_reduced.

34. The system of claim 25, wherein the system comprises a network hub.

35. The system of claim 25, wherein the logic selects said target frequency using a random number, and wherein said random number is determined using a linear congruential generator (LCG).

36. The system of claim 25, wherein the communication logic operates in compliance with the IEEE 802.15.6 protocol.

37. The system of claim 25, wherein the logic hops among said multiple center frequencies in a uniform fashion.