Methods and apparatus for use in simultaneously generating multiple data sequences using a single data access module

• US 6,625,199 B1
• Filed: 10/19/2000
• Issued: 09/23/2003
• 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:
  US09/692,851
• Time in Patent Office: 1,069 Days
• Field of Search: 375/140, 375/147, 375/148, 375/149, 375/150, 714/739, 714/738, 708/250, 708/253, 708/256
• 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

Inventive methods and apparatus for use in simultaneously generating two or more pseudorandom noise (PN) sequences for spread spectrum communications are described. A data sequence generator includes a data access module and a multiplexing device. The multiplexing device has inputs to receive first counter values associated with a first demodulator and second counter values associated with a second demodulator. The multiplexing device has an output to provide, in an interleaved fashion, the first counter values and the second counter values to an input to the data access module. An output from the data access module provides, in an interleaved fashion, PN sequence data responsive to the first counter values and PN sequence data responsive to the second counter values for the first and the second demodulators, respectively. Preferably the data access module is a read-only memory (ROM) having the PN sequence stored therein.

Claims

1. A data sequence generator operative to provide pseudorandom noise (PN) sequences for spread spectrum communications, comprising:

a multiplexer, including;

inputs to receive first counter values associated with a first demodulator and second counter values associated with a second demodulator; and

an output to provide, in a multiplexed fashion, the first counter values and the second counter values;

a converter, for receiving the first counter values and for generating the second counter values responsive to the first counter values; and

a data access module having at least one pseudorandom noise (PN) sequence comprising I and Q PN sequences, used for in-phase and quadrature spreading respectively, encoded therein, having an input coupled to the output of the multiplexer, and having an output to provide, in a time-multiplexed fashion, PN sequence data responsive to the first counter values and PN sequence data responsive to the second counter values.

2. The data sequence generator according to claim 1, wherein the first counter values are derived from an output of a first counter and the second counter values are derived from an output of a second counter.

3. The data sequence generator according to claim 1, where the data access module comprises memory.

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

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

6. The data sequence generator according to claim 1, wherein the data access module comprises a random access memory (RAM).

7. The data sequence generator according to claim 1, wherein the at least one PN sequence comprises I and Q PN sequences used for in-phase and quadrature spreading.

8. The data sequence generator according to claim 1, wherein the at least one PN sequence comprises I and Q PN sequences used. For in-phase and quadrature spreading;

and

wherein the output from said data access module provides PN sequence data from both the I and Q PN sequences.

9. The data sequence generator according to claim 1, wherein the multiplexer further includes:

inputs to receive third counter values associated with a third demodulator;

the outputs to provide the third counter values to the inputs to said data access module in a multiplexed fashion with the first and the second counter values; and

wherein the output from said data access module to provide PN sequence data responsive to the third counter values in a multiplexed fashion with the PN sequence data responsive to the first and the second counter values.

20. The data sequence generator according to claim 1, wherein the data access module provides PN I sequence data responsive to the first counter values;

and wherein the data access module provides PN Q sequence data responsive to the second counter values.

21. The data sequence generator according to claim 1, wherein the data access module provides PN I and Q sequence data responsive to the first counter values;

and wherein the data access module provides Walsh code sequence data responsive to the second counter values.

22. The data sequence generator according to claim 21, wherein the converter performs an addition function.

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

memory;

data stored in said memory;

the data including at least one pseudorandom noise (PN) sequence;

a first counter for use in providing first counter values;

a second counter for use in providing second counter values;

a multiplexing device, including;

inputs to receive the first counter values and the second counter values;

an output to provide, in an interleaved fashion, the first counter values and the second counter values to an input to said memory;

an output from said memory to provide, in an interleaved fashion, PN sequence data responsive to the first counter values and PN sequence data responsive to the second counter values;

a first adder, including;

an input coupled to an output of the first counter;

an output for providing the first counter values;

a second adder, including;

an input coupled to an output of the second counter; and

an output for providing the second counter values.

11. A method for use in generating two or more pseudorandom noise (PN) sequences for spread spectrum communications, comprising:

receiving a counter value associated with a first demodulator;

providing the counter value associated with the first demodulator to an input to a data access module, the data access module having at least one pseudorandom (PN) noise sequence encoded therein;

retrieving, from the data access module, PN sequence data that corresponds to the counter value associated with the first demodulator;

receiving a counter value associated with a second demodulator;

providing the counter value associated with the second demoduator to an input to the data access module;

retrieving, from the data access module, PN sequence data that corresponds to the counter value associated with the second demodulator;

incrementing the counter value associated with the first demodulator;

incrementing the counter value associated with the second demodulator; and

continually repeating the above steps of receiving, providing, retrieving, and incrementing so that a PN sequence is serially produced for the first demodulator and serially produced for the second demodulator.

12. The method according to claim 11, further comprising:

changing the counter value associated with the first demodulator;

changing the counter value associated with the second demodulator; and

repeating the above steps of receiving, providing, retrieving, and changing so that a PN sequence is serially produced for the first demodulator and serially produced for the second demodulator.

13. The method according to claim 11, further comprising:

receiving a counter value associated with a third demodulator;

providing the counter value associated with the third demoduator to the input to the data access module; and

retrieving, from the data access module, PN sequence data that corresponds to the counter value associated with the third demodulator.

14. The method according to claim 11, wherein the data access module comprises memory.

15. The method according to claim 11, further comprising:

the at least one PN sequence comprising I and Q PN sequences used for in-phase and quadrature spreading; and

wherein the steps of retrieving from the data access module comprise retrieving PN sequence data from both the I and Q PN sequences.

16. A method for use in generating pseudorandom noise (PN) sequences for spread spectrum communications, comprising:

receiving, at a multiplexer, first counter values associated with a first demodulator;

providing the first counter values at an input to a data access module having I and Q PN sequences encoded therein;

retrieving, from the data access module, PN data that correspond to the first counter values, for the first demodulator;

converting the first counter values to second counter values associated with a second demodulator;

receiving, at the multiplexer, the second counter values;

providing the second counter values at the input to the data access module at different points in time than the first counter values; and

retrieving, from the data access module, PN data that correspond to the second counter values, for the second demodulator.

17. The method according to claim 16, further comprising:

receiving, at the multiplexer, third counter values associated with a third demodulator;

providing the third counter values at the inputs to the data access module at different points in time than the first and the second counter values; and

retrieving, from the data access module, PN data of the I and Q PN sequences that correspond to the third counter values such that I and Q PN sequences are serially provided for the third demodulator.

18. The method according to claim 16, wherein the data access module comprises memory having the I and Q PN sequences stored therein.

19. The method according to claim 16, wherein the data access module a read-only memory (ROM).

23. The method of claim 16, wherein the step of retrieving PN data that correspond to the first counter values retrieves, from the data access module, PN data of the I PN sequence, for the first demodulator;

and wherein the step of retrieving PN data that correspond to the second counter values retrieves, from the data access module, PN data of the Q PN sequence, for the second demodulator.

24. The method of claim 16, wherein the step of retrieving PN data that correspond to the first counter values retrieves, from the data access module, PN data of the I and Q PN sequences, for the first demodulator;

and wherein the step of retrieving PN data that correspond to the second counter values retrieves, from the data access module, Walsh code data, for the second demodulator.

25. The method of claim 24, wherein the converting step comprises adding to the first counter values.