Matched filter using time-multiplexed precombinations

• US 6,567,483 B1
• Filed: 07/01/1999
• Issued: 05/20/2003
• Est. Priority Date: 11/11/1997
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Roberts, Clarence V., Dent, Paul W.
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US09/345,409
• Time in Patent Office: 1,419 Days
• Field of Search: 375/142, 375/143, 375/150, 375/151, 375/152, 375/153, 375/343, 708/422, 708/423, 708/424, 708/425, 708/426
• US Class Current: 375/343
• CPC Class Codes: G06F 17/15 Correlation function computation including computation of convolution operations arithmetic circuits for sum of products per se, e.g. multiply-accumulators G06F7/5443; digital filters, e.g. FIR, IIR, adaptive filters H03H17/00
• CPC Class Codes: H03H 17/0254 Matched filters
• CPC Class Codes: H04B 1/70751 using partial detection H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/70752 Partial correlation
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 2201/70707 Efficiency-related aspects

Abstract

A technique for correlating a stream of signal sample values with a predetermined binary code having a plurality of binary code bits is disclosed. The technique is realized by forming precombinations of groups of the signal sample values in the stream, and then temporally ordering the precombinations. Particular ones of the temporally ordered precombinations are selected based upon particular combinations of the plurality of binary code bits. The particular selected ones of the temporally ordered precombinations are then combined to form a correlation.

Claims

1. A matched filter for correlating a stream of signal sample values with a predetermined binary code having a plurality of binary code bits, comprising:

a precombiner for forming precombinations of groups of the signal sample values in the stream;

a time-multiplexer for temporally ordering the precombinations;

a plurality of gates for passing selected ones of the temporally ordered precombinations, the temporally ordered precombinations being selected based upon particular combinations of the plurality of binary code bits;

arithmetic combining circuits for combining the selected ones of the temporally ordered precombinations with delayed partial sums to obtain undelayed partial sums; and

delay elements to delay the undelayed partial sums to produce the delayed partial sums.

2. The matched filter of claim 1, wherein the precombinations are temporally ordered into timeslots over a distribution bus.

3. The matched filter of claim 1, wherein each of the plurality of gates is controlled by a group of the plurality of binary code bits.

4. The matched filter of claim 1, wherein the stream of signal sample values are presented at a rate determined by a sample rate clock of a particular frequency, wherein the delay elements are divided into a number of banks of delay elements, each bank being clocked with a respective phase of a multiphase clock derived by dividing the particular frequency of the sample rate clock by the number of banks.

5. The matched filter of claim 4, wherein the number of banks is equal to the number of signal sample values in the groups of signal sample values.

6. The matched filter of claim 1, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values.

7. The matched filter of claim 1, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values divided by two.

8. The matched filter of claim 1, wherein the arithmetic combining circuits include sign changers for changing the sign of the selected ones of the temporally ordered precombinations based upon the values of particular ones of the plurality of binary code bits.

9. A matched filter for correlating a stream of signal sample values with a predetermined binary code having a plurality of binary code bits, comprising:

a precombiner for forming precombinations of groups of the signal sample values in the stream;

a time-multiplexer for temporally ordering the precombinations;

a plurality of gates for passing selected ones of the temporally ordered precombinations, the temporally ordered precombinations being selected based upon particular combinations of the plurality of binary code bits; and

arithmetic combining circuits for combining the selected ones of the temporally ordered precombinations to form a correlation, wherein the arithmetic combining circuits include sign changers for changing the sign of the selected ones of the temporally ordered precombinations based upon the values of particular ones of the plurality of binary code bits.

10. The matched filter of claim 9, wherein the precombinations are temporally ordered into time-slots over a distribution bus.

11. The matched filter of claim 9, wherein each of the plurality of gates is controlled by a group of the plurality of binary code bits.

12. The matched filter of claim 9, wherein the arithmetic combining circuits include delay or memory elements.

13. The matched filter of claim 9, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values.

14. A matched filter for correlating a stream of complex signal sample values with a predetermined complex binary code having a plurality of complex binary code bits, comprising:

a precombiner for forming precombinations of subgroups of groups of real and imaginary parts of the complex signal sample values in the stream, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values divided by two;

a time-multiplexer for temporally ordering the precombinations;

a plurality of gates for passing selected ones of the temporally ordered precombinations, the temporally ordered precombinations being selected based upon particular combinations of the plurality of binary code bits; and

arithmetic combining circuits for combining a first half of the selected ones of the temporally ordered precombinations to form a real part of a complex correlation, and for combining a second half of the selected ones of the temporally ordered precombinations to form an imaginary part of the complex correlation.

15. The matched filter of claim 14, wherein the precombinations are temporally ordered into time-slots over a distribution bus.

16. The matched filter of claim 14, wherein each of the plurality of gates is controlled by a group of the plurality of complex binary code bits.

17. The matched filter of claim 14, wherein the arithmetic combining circuits include delay or memory elements.

18. The matched filter of claim 14, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values.

19. The matched filter of claim 14, wherein the arithmetic combining circuits are time-shared to combine the first half of the selected ones of the temporally ordered precombinations at given time instants, and to combine the second half of the selected ones of the temporally ordered precombinations at intervening time instants.

20. The matched filter of claim 14, wherein the precombinations are temporally ordered into time-slots over a distribution bus.

21. The matched filter of claim 14, wherein each of the plurality of gates is controlled by a group of the plurality of complex binary code bits.

22. The matched filter of claim 14, wherein the arithmetic combining circuits include delay or momory elements.

23. The matched filter of claim 14, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values.

24. The matched filter of claim 14, wherein the arithmetic combining circuits are time-shared to combine the first half of the selected ones of the temporally ordered precombinations at given time instants, and to combine the second half of the selected ones of the temporally ordered precombinations at intervening time instants.

25. A matched filter for correlating a stream of signal sample values with a predetermined binary code having a plurality of binary code bits, comprising:

a precombiner for forming precombinations of groups of the signal sample values in the stream, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values divided by two;

a time-multiplexer for temporally ordering the precombinations;

a plurality of gates for passing selected ones of the temporally ordered precombinations, the temporally ordered precombinations being selected based upon particular combinations of the plurality of binary code bits; and

arithmetic combining circuits for combining the selected ones of the temporally ordered precombinations to form a correlation.

26. The matched filter of claim 25, wherein the precombinations are temporally ordered into time-slots over a distribution bus.

27. The matched filter of claim 25, wherein each of the plurality of gates is controlled by a group of the plurality of binary code bits.

28. The matched filter of claim 25, wherein the arithmetic combining circuits include delay or memory elements.

29. The matched filter of claim 25, wherein the number of precombinations formed is equal to two to the power of the number of signal sample values in the groups of signal sample values.

30. A matched filter for correlating a stream of complex signal sample values with a predetermined complex binary code having a plurality of complex binary code bits, comprising:

a precombiner for forming precombinations of subgroups of groups of real and imaginary parts of the complex signal sample values in the stream;

a time-multiplexer for temporally ordering the precombinations;

a plurality of gates for passing selected ones of the temporally ordered precombinations, the temporally ordered precombinations being selected based upon particular combinations of the plurality of binary code bits; and

arithmetic combining circuits for combining a first half of the selected ones of the temporally ordered precombinations to form a real part of a complex correlation, and for combining a second half of the selected ones of the temporally ordered precombinations to form an imaginary part of the complex correlation, wherein the arithmetic combining circuits include sign changers for changing the sign of the selected ones of the temporally ordered precombinations based upon the values of particular ones of the plurality of complex binary code bits.