Methods and apparatus for use in simultaneously generating data sequences for spread spectrum communications

• US 6,650,687 B1
• Filed: 10/19/2000
• Issued: 11/18/2003
• Est. Priority Date: 05/28/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: McDonough, John G.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Kim, Kevin
• Application Number:
  US09/692,849
• Time in Patent Office: 1,125 Days
• Field of Search: 375/130, 375/140, 375/146, 714/739, 714/738, 708/250, 708/253, 708/256, 380/46
• US Class Current: 375/140
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/10 Code generation

Abstract

One particular data sequence generator for spread spectrum communications includes a first data access module, a second data access module, and a binary counter for use in repeatedly providing counter values from 0 to 2¹⁵−1 at a 15-bit output. The first data access module, which may include a read-only memory (ROM), has first and second pseudorandom noise (PN) sequences encoded therein, each having a length of 2¹⁵. The first data access module has a 15-bit input coupled to the 15-bit output providing the counter values. The first, data access module also has a first bit output to provide a selected PN bit of the first PN sequence and a second bit output to provide a selected PN bit of the second PN sequence responsive to each one of the counter values from 0 to 2¹⁵−1. The second data access module, which may also include a ROM, has an N-bit input coupled to N lines of the 15-bit output. The second data access module provides Walsh code data of a 2^N-by-2^N Hadamard matrix responsive to each counter value at the N-bit input.

Claims

1. A data sequence generator for spread spectrum communications, comprising:

a counter for use in repeatedly providing L discrete counter values at an output;

a first data access module, including;

an input coupled to the output that provides the L discrete counter values;

an output to provide data of a first data sequence responsive to each one of the L discrete counter values, the first data sequence having a length L; and

a second data access module, including;

an input coupled to receive M discrete counter values derived from the output providing the L discrete counter values, M differing from L;

an output to provide data of a second data sequence responsive to each one of the M discrete counter values;

wherein the first data sequence comprises a pseudorandom noise (PN) sequence.

7. The data sequence generator according to claim 1, wherein the first data access module comprises memory.

8. The data sequence generator according to claim 1, wherein the first data access module comprises a read-only memory (ROM).

9. The data sequence generator according to claim 1, wherein the second data access module comprises combinatorial logic.

10. The data sequence generator according to claim 1, wherein the first data access module comprises one of memory and combinatorial logic, and wherein the second data access module comprises one of memory and combinatorial logic.

2. A data sequence generator for spread spectrum communications, comprising:

a counter for use in repeatedly providing L discrete counter values at an output;

a first data access module, including;

an input coupled to the output that provides the L discrete counter values;

an output to provide data of a first data sequence responsive to each one of the L discrete counter values, the first data sequence having a length L; and

a second data access module, including;

an input coupled to receive M discrete counter values derived from the output providing the L discrete counter values, M differing from L;

an output to provide data of a second data sequence responsive to each one of the M discrete counter values;

wherein the first data sequence comprises a pseudorandom (PN) sequence and L=2¹⁵.

3. A data sequence generator for spread spectrum communications, comprising:

a counter for use in repeatedly providing l discrete counter values at an output;

a first data access module, including;

an input coupled to the output that provides the L discrete counter values;

an output to provide data of a first data sequence responsive to each one of the L discrete counter values, the first data sequence having a length L a second data access module, including;

an input coupled to receive m discrete counter values derived from the output providing the L discrete counter values;

an output to provide data of a second data sequence responsive to each one of the M discrete counter values; and

wherein the second data sequence comprises Walsh code data of a Hadamard matrix.

4. A data sequence generator for spread spectrum communications, comprising:

a counter for use in repeatedly providing L discrete counter values at an output;

a first data access module, including;

an input coupled to the output that provides the L discrete counter values;

an output to provide data of a first data sequence responsive to each one of the L discrete counter values, the first data sequence having a length L;

a second data access module, including;

an input coupled to receive M discrete counter values derived from the output providing the L discrete counter values;

an output to provide data of a second data sequence responsive to each one of the M discrete counter values; and

wherein the first data sequence comprises a pseudorandom noise (PN) sequence and the second data sequence comprises Walsh code data of a Hadamard matrix.

5. A data sequence generator for spread spectrum communications, comprising:

a counter for use in repeatedly providing L discrete counter values at an output;

a first data access module, including;

an input coupled to the output that provides the L discrete counter values;

an output to provide data of a first data sequence responsive to each one of the L discrete counter values, the first data sequence having a length L;

a second data access module, including;

an input coupled to receive M discrete counter values derived from the output providing the L discrete counter values;

an output to provide data of a second data sequence responsive to each one of the M discrete counter values; and

wherein the input of the second data access module is coupled to only a portion of the output that provides the L discrete counter values.

6. A data sequence generator for spread spectrum communications, comprising:

a counter for use in repeatedly providing L discrete counter values at an output;

a first data access module, including;

an input coupled to the output that provides the L discrete counter values;

an output to provide data of a first data sequence responsive to each one of the L discrete counter values, the first data sequence having a length L;

a second data access module, including;

an input coupled to receive M discrete counter values derived from the output providing the L discrete counter values;

an output to provide data of a second data sequence responsive to each one of the M discrete counter values; and

wherein L=2¹⁵ and M<

2¹⁵.

11. A method for use in simultaneously generating two or more data sequences in spread spectrum communications, comprising:

providing first binary counter data at an input of a first data access module;

repeatedly changing the first binary counter data at a chip rate to provide L discrete values at the input of the first data access module;

for each value of the discrete values at the input of the first data access module, providing a selected bit of a pseudorandom noise (PN) sequence having a length l at an output of the first data access module;

providing second binary counter data, which are derived from the first binary counter data, at an input to a second data access module so that M discrete values are provided at the input of the second data access module, wherein M<

L; and

for each value of the m discrete values at the input of the second data access module, providing a selected Walsh code bit of a Hadamard matrix at an output of the second data access module.

12. The method according to claim 11, wherein providing a selected Walsh code bit further comprises a substep of providing a column of a Hadamard matrix.

13. The method according to claim 11, wherein the Hadamard matrix comprises an M-by-M Hadamard matrix, the method further comprising:

deriving the second binary counter data based on modulo M of the first binary counter data.

14. The method according to claim 11, wherein the Hadamard matrix comprises 64-by-64 Hadamard matrix, the method further comprising:

deriving the second binary counter data based on modulo 64 of the first binary counter data.

15. The method according to claim 11, wherein L=2¹⁵ and M=64.

16. A method according to claim 11, wherein the first data access module comprises one of memory and combinatorial logic, and wherein the second data access module comprises one of memory and combinatorial logic.

17. The method according to claim 11, wherein the first and the second data access modules comprise memory.

18. The method according to claim 11, wherein at least the first data access module comprises a read-only memory (ROM).

19. A method for use in simultaneously generating both pseudorandom noise (PN) sequences and Walsh sequences, the method comprising:

repeatedly generating counter values from 0 to 2¹⁵−

1 at a 15-bit output;

providing the 15-bit output at a 15-bit input of a data access module having at least one PN sequence of length 2¹⁵ encoded therein;

serially generating the at least one PN sequence at an output of the data access module in response to the counter values from 0 to 2¹⁵−

1 provided at the 15-bit input;

providing N bits of the 15-bit output at an N-bit input of the data access module; and

serially generating a Walsh sequence at an output of the data access module in response to counter values from 0 to 2^N−

1 provided at the N-bit input.

20. The method according to claim 19, wherein the data access module has a first PN I sequence and a second PN Q sequence of length 2¹⁵ encoded therein, the method further comprising:

wherein serially generating the at least one PN sequence comprises serially generating the PN I sequence and the PN Q sequence at substantially the same time.

21. The method according to claim 19, wherein serially generating a Walsh sequence comprises serially providing a column of an N-by-N Hadamard matrix.

22. The method according to claim 19, wherein the data access module comprises memory.

23. The method according to claim 19, wherein the data access module comprises combinatorial logic.

24. A data sequence generator for spread spectrum communications, comprising:

at least one binary counter for use in repeatedly providing counter values from 0 to 2¹⁵−

1 at a 15-bit output;

a first data access module;

the first data access module comprising a read-only memory (ROM);

the first data access module having first and second pseudorandom noise (PN) sequences encoded therein, each one of the first and second PN sequences having a length of 2¹⁵;

the first data access module having a 15-bit input coupled to the 15-bit output;

the first data access module having a first bit output to provide a selected PN bit of the first PN sequence and a second bit output to provide a selected PN bit of the second PN sequence responsive each one of the counter values from 0 to 2¹⁵−

1;

a second data access module;

the second data access module having an N-bit input coupled to N bits of the 15-bit output; and

the second data access module to provide Walsh code data of a 2^N-by-2^N Hadamard matrix responsive to each counter value at the N-bit address input.

25. The data sequence generator according to claim 24, further comprising:

wherein the first and the second PN sequences comprise PN I and PN Q sequences.

26. The data sequence generator according to claim 24, further comprising:

the second data access module comprising one of memory and combinatorial logic.