Frequency-hopping scheme

• US 8,374,214 B2
• Filed: 04/13/2010
• Issued: 02/12/2013
• Est. Priority Date: 04/13/2009
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Roh, June Chul, Batra, Anuj
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): Garcia, Santiago
• Application Number:
  US12/759,684
• Publication Number:
  US 20100260232A1
• Time in Patent Office: 1,036 Days
• Field of Search: 375/133
• 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 a logic unit, a plurality of multiple random numbers evenly distributed over a range;

determining a next frequency in said sequence using said plurality of multiple random numbers; and

one or more of a minimum separation, a channel number, and a number of channels; and

hopping to said next frequency, wherein said range is determined using the equation Nreduced=Nch−

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

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.

5. The method of claim 1, wherein generating said plurality of multiple random numbers comprises performing a modulo function between a random number from said plurality of multiple random numbers and a number of possible channel numbers.

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

generating, by a logic unit, a plurality of multiple random numbers evenly distributed over a range;

determining a next frequency in said sequence using said plurality of multiple random numbers; and

one or more of a minimum separation, a channel number, and a number of channels; and

hopping to said next frequency, wherein generating said random number comprises using the equation z(k+1)=[(y(k+1)+k)mod Nreduced], 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 Nreduced comprises Nch−

2Nsep+1, wherein Nch comprises said number of channels and Nsep comprises the minimum separation.

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

generating, by a logic unit, a plurality of multiple random numbers evenly distributed over a range;

determining a next frequency in said sequence using said plurality of multiple random numbers; and

one or more of a minimum separation, a channel number, and a number of channels; and

hopping to said next frequency, 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 Nreduced, wherein Nreduced=Nch−

2Nsep+1, and wherein Nch is said number of channels and Nsep 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 Nreduced.

7. The method of claim 6, wherein generating said random number comprises using a linear congruential generator (LCG).

8. The method of claim 6, wherein generating, determining and hopping comprise generating, determining, and hopping in compliance with the IEEE 802.15.6 protocol.

9. 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, 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;

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.

10. The method of claim 9, wherein said predetermined number of channels comprises a coherence bandwidth or a fraction of said coherence bandwidth.

11. The method of claim 9, 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.

12. 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;

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 resister, 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.

13. The system of claim 12, wherein said minimum separation comprises a coherence bandwidth or a fraction of said coherence bandwidth.

14. A system, comprising:

logic; and

communication logic coupled to the logic;

wherein the logic causes the communication logic to hog 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, 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.

15. The system of claim 14, wherein the system comprises a network hub.

16. The system of claim 14, wherein the communication logic operates in compliance with the IEEE 802.15.6 protocol.