Configurable de-interleaver design

• US 20070110178A1
• Filed: 11/11/2006
• Published: 05/17/2007
• Est. Priority Date: 11/11/2005
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Hammerschmidt, Joachim, Su, Ling
• Application Number:
  US11/595,618
• Publication Number:
  US 20070110178A1
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H03M 13/2707 Simple row-column interleaver, i.e. pure block interleaving
• CPC Class Codes: H03M 13/31 combining coding for error detection or correction and efficient use of the spectrum without error detection or correction H03M5/14 , H03M5/145
• CPC Class Codes: H03M 13/41 using the Viterbi algorithm or Viterbi processors
• CPC Class Codes: H03M 13/6508 Flexibility, adaptability, parametrability and configurability of the implementation
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0052 Realisations of complexity reduction techniques, e.g. pipelining or use of look-up tables
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

An integrated circuit radio transceiver and method therefor is operable to flexibly and efficiently de-interleave a received communication signal by initially changing a received signal from the time domain to the frequency domain to generate a plurality of tones that are then rearranged in a first de-interleaving step to an order expected by a downstream decoder. Thereafter, the tones are detected to generate a soft bit sequence and are then reverse-swizzled and de-interleaved. The de-interleaving step is performed in a manner that compensates for row/column offset interleaving performed by a transmitter that transmitted the received signal being processed.

Claims

1. A method for processing and de-interleaving a received signal, comprising:

receiving a continuous wave radio frequency signal and front end processing the radio frequency signal to filter, amplify and down-convert the radio frequency signal to produce a down-converted ingoing signal;

converting the ingoing signal from a time domain signal to a frequency domain signal wherein the frequency domain signal comprises a plurality of tones arranged in a first sequence;

tone de-interleaving the plurality of tones by re-arranging the first sequence of tones into a second sequence;

producing a specified number of tones from the second sequence to a corresponding specified number of detector arrays that are each operable to generate a bit stream portion therefrom; and

combining the bit steam portions produced by the detector array to create an ingoing bit stream;

bit de-interleaving the ingoing bit stream to create a de-interleaved bit stream that, without transmission interference, matches an outgoing bit stream in a transmitter prior to scrambling and interleaving by the transmitter that generated the received signal.

2. The method of claim 1 wherein the step of re-arranging the first sequence of tones into the second sequence of tones in the tone de-interleaving step compensates for scrambling performed by the transmitter.

3. The method of claim 1 wherein the step of bit de-interleaving the ingoing bit stream includes reverse swizzling the ingoing bit stream to produce a reverse-swizzled bit stream that corresponds to an interleaved bit stream in the transmitter prior to swizzling.

4. The method of claim 3 further comprising determining a starting swizzling phase value that, upon reverse swizzling, generates correctly de-swizzled bits and de-swizzling the bits.

5. The method of claim 4 further including cyclicly changing the swizzling phase value to compensate for changes in the transmitter swizzling phase values prompted by changes in either a column or row of interleaving table(s) of a transmitter interleaver.

6. The method of claim 3 wherein the step of de-interleaving the ingoing bit stream includes simultaneously reverse frequency rotating and reverse interleaving the reverse-swizzled bit stream.

7. The method of claim 6 wherein the step of simultaneously reverse frequency rotating and reverse interleaving the reverse-swizzled bit stream includes:

storing the reverse-swizzled bit stream in a table that corresponds in dimensions to an interleaving table used by the transmitter that transmitted the received signal;

sequentially extracting bits from the interleaving table starting at a specified offset location to generate the de-interleaved bit stream that corresponds to a bit sequence order in which bits were received for storing in the interleaving table of the transmitter.

8. The method of claim 5 further including Viterbi decoding the de-interleaved bit stream.

9. Circuitry for processing and de-interleaving a received signal, which received signal was scrambled and interleaved by a transmitter, comprising:

tone de-interleaving circuitry for receiving a first sequence of tones and for rearranging the first sequence of tones into a second sequence of tones, which rearranging to produce the second sequence of tones operably compensates for the scrambling performed by the transmitter and arranges the tones in an order expected by a downstream decoder;

logic for selecting a number of tones from the second sequence of tones for detection to generate a soft bit sequence;

a plurality of detector array circuits each operable to produce a bit sequence from a selected tone, wherein the number of the plurality of detector array circuits corresponds to the number of tones selected from the second sequence of tones wherein each of the plurality of detector array circuits receives one of the tones selected from the second sequence of tones; and

de-interleaving circuitry to de-interleave bit sequences produced by the number of the plurality of detector array circuits.

10. The circuitry of claim 9 wherein the de-interleaving circuitry further includes a plurality of block de-interleaving circuit paths that correspond to a number of interleaving circuit paths used by the transmitter.

11. The circuitry of claim 10 wherein each of the plurality of block de-interleaving circuit paths include reverse swizzling circuitry operable to swizzle a bit stream received from at least one detector array circuit in an order that compensates for swizzling of a swizzler of the transmitter wherein the reverse swizzling circuitry produces a reverse-swizzled bit stream.

12. The circuitry of claim 11 further including logic for creating a table in memory characterized by N rows and N columns, which table corresponds in dimensions to an interleaving table used by the transmitter that generated the received signal.

13. The circuitry of claim 12 further including logic for de-interleaving bits in the table by reverse interleaving and reverse frequency rotating the reverse-swizzled bit stream by sequentially extracting bits from the table in an order that generates bits in an order in which bits were stored in the interleaving table of the transmitter to produce a de-interleaved bit stream.

14. The circuitry of claim 9 wherein the logic that selects the tones from the second sequence of tones is operable to sequentially arrange the tones in an order expected by a down-stream Viterbi decoder.

15. Circuitry for processing and de-interleaving a received signal, comprising:

de-interleaving circuitry to de-interleave received bit sequences produced by a number of detector array circuits wherein the de-interleaving circuitry further includes a plurality of block de-interleaving circuit paths that correspond to a number of interleaving circuit paths used by a transmitter that generated the received signal; and

wherein the de-interleaving circuitry includes logic to generate a table that is sized the same as an interleaving table of interleaving circuitry of a transmitter and further wherein the de-interleaving circuitry begins to extract bits from the table from an offset location that corresponds to an offset location utilized within the transmitter to interleave the bits prior to transmission.

16. The circuitry of claim 15 further including logic for creating the table in memory characterized by N rows and N columns, which table corresponds in dimensions to the interleaving table used by the transmitter that generated the received signal.

17. The circuitry of claim 16 further including logic for de-interleaving bits in the table by reverse interleaving and reverse frequency rotating a reverse-swizzled bit stream by sequentially extracting bits from the table in an order that generates bits in an order in which bits were stored in the interleaving table of the transmitter to produce a de-interleaved bit stream.

18. The circuitry of claim 15 further including tone de-interleaving circuitry for receiving and processing a first sequence of tones.

19. The circuitry of claim 18 wherein the tone de-interleaving circuitry is operable to rearrange the first sequence of tones into a second sequence of tones, which second sequence of tones operably compensates for scrambling performed by the transmitter that generated the received signal prior to interleaving outgoing bits.

20. The circuitry of claim 19 further including logic for selecting a number of tones from the second sequence of tones.

21. The circuitry of claim 20 further including a number of detector array circuits each operable to produce a bit sequence from a tone, wherein the number of detector array circuits corresponds to the number of tones selected from the second sequence of tones wherein each of the detector array circuits receives one of the tones selected from the second sequence of tones.

22. The circuitry of claim 21 wherein each of the detector array circuits produces the bits sequences and are combined in a specified order that corresponds to a bit sequence produced by swizzling circuitry in the transmitter prior to transmission.

23. The circuitry of claim 22 wherein each de-interleaving circuit path includes reverse swizzling circuitry operable to swizzle the bit stream received from at least one detector array circuit in an order that compensates for swizzling of a swizzler of the transmitter wherein the reverse swizzling circuitry produces a reverse-swizzled bit stream.

24. The circuitry of claim 23 wherein the reverse-swizzled bit stream is produced to the de-interleaving circuitry to de-interleave the reverse-swizzled bit stream.