Systems for programmably interleaving and de-interleaving data and method thereof

• US 5,928,371 A
• Filed: 07/25/1997
• Issued: 07/27/1999
• Est. Priority Date: 07/25/1997
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Robinson, Charles D. Jr., Sudhaman, Sujit, Voith, Raymond P.
• Primary Examiner(s): DeCady, Albert
• Assistant Examiner(s): ABRAHAM, ESAW T
• Application Number:
  US08/910,475
• Time in Patent Office: 732 Days
• Field of Search: 714/701, 714/702, 714/756, 714/762, 370/241, 324/73.1
• US Class Current: 714/702
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

A data interleaving system (20) provides flexibility by performing the interleaving function in a high level controller (32) and a separate low level controller (34). The high level controller (32) receives commands to operate on a codeword basis, in which a codeword is made up of a plurality of symbols which are grouped into a programmable number of frames. The low level controller (34) operates under the direction of the high level controller (32) on a symbol-by-symbol basis. By separating the codeword level tasks from the symbol level tasks, the data interleaving system (20) is able to accommodate various ratios of the number of frames per codeword without significant complexity. An analogous data de-interleaving system (220) includes a high level controller (232) and a low level controller (234).

Claims

1. A system for programmably interleaving communications data that separates interleaving operations at a codeword level from interleaving operations at a symbol level, wherein:

a codeword is an ordered grouping of N symbols to be interleaved to a depth of D;

said system comprising;

a high level interleaver that is responsive to a set of high level interleaving signals, that is controlled by a set of high level interleaving parameters, and which works at the codeword level; and

a low level interleaver that is responsive to a set of low level interleaving signals provided by the high level interleaver, that is controlled by a set of low level interleaving parameters, and which works at the symbol level.

2. The system in claim 1 which further comprises:

an interleaver memory that is written by and read from the low level interleaver.

3. The system in claim 1 which further comprises:

a top level controller that provides the set of high level interleaving signals to the high level interleaver.

4. The system in claim 1 which further comprises:

an interleaver input buffer that is read by the high level interleaver; and

an interleaver output buffer that is written by the high level interleaver.

5. The system in claim 4 wherein the interleaver input buffer is a same buffer as the interleaver output buffer.

6. The system in claim 1 wherein:

the set of low level interleaving signals comprise;

a low level interleaver read signal,

a low level interleaver write signal, and

a low level interleaver go signal to activate the low level interleaver; and

the low level interleaver provides a low level interleaver done signal to the high level interleaver when it completes.

7. The system in claim 1 wherein:

the set of low level interleaving parameters comprises;

an interleaver buffer address,

an interleaving codeword size N,

an interleaving depth D, and

an interleaver memory address limit; and

the set of low level interleaving signals comprises;

a low level go signal to activate the low level interleaver.

8. The system in claim 1 wherein:

the set of high level interleaving parameters comprises;

a write count to specify how many symbols for the low level interleaver to write without a corresponding read,

a write/read count to specify how many symbols for the low level interleaver to write and read, and

a read count to specify how many symbols for the low level interleaver to read without a corresponding write; and

the set of high level interleaving signals comprises;

a high level go signal to activate the high level interleaver.

9. A method of interleaving data with a plurality of frames per codeword utilizing the system in claim 8 wherein:

each codeword contains S frames,

each of the plurality of frames contains N/S symbols;

each codeword contains N symbols;

each codeword contains P payload symbols and R redundancy symbols,

said method comprising;

A) initializing high level interleaver parameters comprising the substeps of;

1) initializing the write count to zero,

2) initializing the write/read count to (P/S), and

3) initializing the read count to (R/S),

B) activating the high level interleaver (S-1) times by asserting the high level interleaver go signal after step (A);

C) initializing high level interleaver parameters comprising the substeps of;

1) initializing the write count to (R/S)*(S-1),

2) initializing the write/read count to (N/S), and

3) initializing the read count to zero; and

D) activating the high level interleaver by asserting a high level interleaver go signal after step (C).

10. The system in claim 1 wherein:

the high level interleaver and the low level interleaver interleave ADSL data;

each symbol is an eight bit byte; and

N and D are relatively coprime integers.

11. The system in claim 1 wherein the low level interleaver comprises:

a low level write circuit for controlling a writing of a symbol;

a low level read circuit for controlling a reading of a symbol, and

a low level controller for controlling the low level write circuit and the low level read circuit.

12. The system in claim 11 wherein the low level write circuit comprises:

a write address register containing a write address;

an ALU that receives the write address from the write address register and provides an updated write address to the write address register;

a MUX to select one of a plurality of parameter values as an input value to the ALU for a purpose of modifying the write address;

a write address comparator for determining when the write address exceeds a write address limit; and

a counter to determine when an entire frame of N symbols has been written.

13. The system in claim 12 wherein the low level controller comprises:

a write address fix circuit responsive to a write address overflow signal from the write address comparator that provides control signals to the MUX and the ALU to adjust the write address in the write address register to compensate for write address wraparound.

14. The system in claim 11 wherein the low level read circuit comprises:

a read address register containing a read address wherein;

the read address register is an incrementer that increments the read address for each read request to the low level read circuit; and

a read address comparator for determining when the read address exceeds a read address limit.

15. The system in claim 14 wherein the low level controller comprises:

a read address fix circuit responsive to a read address overflow signal from the read address comparator that provides a control signal to reinitialize the read address register to an initial read address value.

16. The system in claim 11 which further comprises:

an interleaver memory address register for providing a memory address to an interleaver memory,

a second MUX that selectively provides either a write address from a write address register or a read address from a read address register to the interleaver memory address register,

a write data register for providing a write data operand for writing to the write address in the interleaver memory, and

a read data register for receiving a read data operand read from the read address in the interleaver memory.

17. The system in claim 11 wherein:

the system further comprises;

an interleaver memory accessed by the low level interleaver;

the low level interleaver includes a read data register and a write data register; and

the set of low level interleaving signals comprises;

a write signal that selectively activates the low level write circuit to write a symbol from the write data register to the interleaver memory, and

a read signal that selectively activates the low level read circuit to read one symbol from the interleaver memory into the read data register.

18. The system in claim 11 wherein:

the low level write circuit comprises;

a write address register containing a write address,

an ALU that receives the write address from the write address register and provides an updated write address to the write address register,

a MUX to select one of a plurality of parameter values as an input value to the ALU for a purpose of modifying the write address,

a write address comparator for determining when the write address exceeds a write address limit, and

a counter to determine when an entire frame of N symbols has been written;

the low level read circuit comprises;

a read address register containing a read address wherein;

the read address register is an incrementer that increments the read address for each read request to the low level read circuit, and

a read address comparator for determining when the read address exceeds a read address limit; and

the low level controller comprises;

a write address fix circuit responsive to a write address overflow signal from the write address comparator that provides control signals to the MUX and the ALU to adjust the write address in the write address register to compensate for write address wraparound, and

a read address fix circuit responsive to a read address overflow signal from the read address comparator that provides a control signal to reinitialize the read address register to an initial read address value.

19. The system in claim 11 wherein:

the set of low level interleaving signals comprise;

a low level interleaver go signal to activate the low level interleaver,

a low level interleaver write signal to selectively activate the low level write circuit when the low level interleaver go signal is asserted, and

a low level interleaver read signal to selectively activate the low level read circuit when the low level interleaver go signal is asserted; and

the low level interleaver provides a low level interleaver done signal to the high level interleaver after the low level write circuit if selectively activated is done and the low level read circuit if selectively activated is done.

20. The system in claim 19 wherein:

the set of high level interleaving parameters comprises;

a write count to specify how many symbols for the low level interleaver to write without a corresponding read,

a write/read count to specify how many symbols for the low level interleaver to write and read, and

a read count to specify how many symbols for the low level interleaver to read without a corresponding write; and

an operation of the high level interleaver comprises the steps of;

activating the low level interleaver a first integer number of times specified by the write count by;

asserting the low level interleaver go signal with the low level interleaver write signal asserted and the low level interleaver read signal negated, and

waiting for the low level interleaver done signal,

activating the low level interleaver a second integer number of times specified by the write/read count by;

asserting the low level interleaver go signal with the low level interleaver write signal asserted and the low level interleaver read signal asserted, and

waiting for the low level interleaver done signal, and

activating the low level interleaver a third integer number of times specified by the read count by;

asserting the low level interleaver go signal with the low level interleaver write signal negated and the low level interleaver read signal asserted and

waiting for the low level interleaver done signal.

21. A system for programmably deinterleaving communications data that separates deinterleaving operations at a codeword level from deinterleaving operations at a symbol level, wherein:

a codeword is an ordered grouping of N symbols to be deinterleaved to a depth of D;

said system comprising;

a high level deinterleaver that is responsive to a set of high level deinterleaving signals, that is controlled by a set of high level deinterleaving parameters, and which works at the codeword level; and

a low level deinterleaver that is responsive to a set of low level deinterleaving signals provided by the high level deinterleaver, that is controlled by a set of low level deinterleaving parameters, and which works at the symbol level.

22. The system in claim 21 which further comprises:

a deinterleaver memory that is written by and read from the low level deinterleaver.

23. The system in claim 21 which further comprises:

a top level controller that provides the set of high level deinterleaving signals to the high level deinterleaver.

24. The system in claim 21 which further comprises:

a deinterleaver input buffer that is read by the high level deinterleaver; and

a deinterleaver output buffer that is written by the high level deinterleaver.

25. The system in claim 24 wherein the deinterleaver input buffer is a same buffer as the deinterleaver output buffer.

26. The system in claim 21 wherein:

the set of low level deinterleaving signals comprise;

a low level deinterleaver write signal,

a low level deinterleaver read signal, and

a low level deinterleaver go signal to activate the low level deinterleaver; and

the low level deinterleaver provides a low level deinterleaver done signal to the high level deinterleaver when it completes.

27. The system in claim 21 wherein:

the set of low level deinterleaving parameters comprises;

a deinterleaver buffer address,

a deinterleaving codeword size N,

a deinterleaving depth D, and

a deinterleaver memory address limit; and

the set of low level deinterleaving signals comprises;

a low level go signal to activate the low level deinterleaver.

28. The system in claim 21 wherein:

the set of high level deinterleaving parameters comprises;

a write/read count to specify how many symbols for the low level deinterleaver to write and read, and

the set of high level deinterleaving signals comprises;

a high level go signal to activate the high level deinterleaver.

29. A method of deinterleaving data with a plurality of frames per codeword utilizing the system in claim 28 wherein:

each codeword contains S frames,

each of the plurality of frames contains N/S symbols;

each codeword contains N symbols;

each codeword contains P payload symbols and R redundancy symbols,

said method comprising;

A) accumulating the P payload symbols and R redundancy symbols from the S frames in an accumulation buffer;

B) initializing the write/read count to (P+R); and

C) activating the high level interleaver by asserting the high level deinterleaver go signal after steps (A) and (B) to deinterleave input data in the accumulation buffer.

30. The system in claim 21 wherein:

the high level deinterleaver and the low level deinterleaver deinterleave ADSL data;

each symbol is an eight bit byte; and

N and D are relatively coprime integers.

31. The system in claim 21 wherein the low level deinterleaver comprises:

a low level read circuit for controlling a reading of a symbol;

a low level write circuit for controlling a writing of a symbol, and

a low level controller for controlling the low level read circuit and the low level write circuit.

32. The system in claim 31 wherein the low level read circuit comprises:

a read address register containing a read address;

an ALU that receives the read address from the read address register and provides an updated read address to the read address register;

a MUX to select one of a plurality of parameter values as an input value to the ALU for a purpose of modifying the read address;

a read address comparator for determining when the read address exceeds a read address limit; and

a counter to determine when an entire frame of N symbols has been read.

33. The system in claim 32 wherein the low level controller comprises:

a read address fix circuit responsive to a read address overflow signal from the read address comparator that provides control signals to the MUX and the ALU to adjust the read address in the read address register to compensate for read address wraparound.

34. The system in claim 31 wherein the low level write circuit comprises:

a write address register containing a write address wherein;

the write address register is an incrementer that increments the write address for each write request to the low level write circuit; and

a write address comparator for determining when the write address exceeds a write address limit.

35. The system in claim 34 wherein the low level controller comprises:

a write address fix circuit responsive to a write address overflow signal from the write address comparator that provides a control signal to reinitialize the write address register to an initial write address value.

36. The system in claim 31 which further comprises:

a deinterleaver memory address register for providing a memory address to a deinterleaver memory,

a second MUX that selectively provides either a read address from a read address register or a write address from a write address register to the deinterleaver memory address register,

a read data register for receiving a read data operand read from the read address in the deinterleaver memory, and

a write data register for providing a write data operand written to the write address in the deinterleaver memory.

37. The system in claim 31 wherein:

the system further comprises;

a deinterleaver memory accessed by the low level deinterleaver;

the low level deinterleaver includes a write data register and a read data register; and

the set of low level deinterleaving signals comprises;

a write signal that selectively activates the low level write circuit to write a symbol from the write data register to the deinterleaver memory, and

a read signal that selectively activates the low level read circuit to read one symbol from the deinterleaver memory into the read data register.

38. The system in claim 31 wherein:

the low level read circuit comprises;

a read address register containing a read address,

an ALU that receives the read address from the read address register and provides an updated read address to the read address register,

a MUX to select one of a plurality of parameter values as an input value to the ALU for a purpose of modifying the read address,

a read address comparator for determining when the read address exceeds a read address limit, and

a counter to determine when an entire frame of N symbols has been read;

the low level write circuit comprises;

a write address register containing a write address wherein;

the write address register is an incrementer that increments the write address for each write request to the low level write circuit, and

a write address comparator for determining when the write address exceeds a write address limit; and

the low level controller comprises;

a read address fix circuit responsive to a read address overflow signal from the read address comparator that provides control signals to the MUX and the ALU to adjust the read address in the read address register to compensate for read address wraparound, and

a write address fix circuit responsive to a write address overflow signal from the write address comparator that provides a control signal to reinitialize the write address register to an initial write address value.

39. The system in claim 31 wherein:

the set of low level deinterleaving signals comprise;

a low level deinterleaver go signal to activate the low level deinterleaver,

a low level deinterleaver read signal to selectively activate the low level read circuit when the low level deinterleaver go signal is asserted, and

a low level deinterleaver write signal to selectively activate the low level write circuit when the low level deinterleaver go signal is asserted; and

the low level deinterleaver provides a low level deinterleaver done signal to the high level deinterleaver after the low level read circuit if selectively activated is done and the low level write circuit if selectively activated is done.

40. The system in claim 39 wherein:

the set of high level deinterleaving parameters comprises;

a write/read count to specify how many symbols for the low level deinterleaver to write and read; and

an operation of the high level deinterleaver comprises the steps of;

activating the low level deinterleaver an integer number of times specified by the write/read count by;

asserting the low level deinterleaver go signal with the low level deinterleaver read signal asserted and the low level deinterleaver write signal asserted, and

waiting for the low level deinterleaver done signal.

41. A system for programmably interleaving and deinterleaving communications data that separates interleaving and deinterleaving operations at a codeword level from interleaving and deinterleaving operations at a symbol level, wherein:

a codeword is an ordered grouping of N symbols to be interleaved to a depth of D;

said system comprising;

a high level interleaver that is responsive to a set of high level interleaving signals, that is controlled by a set of high level interleaving parameters, and which works at the codeword level;

a low level interleaver that is responsive to a set of low level interleaving signals provided by the high level interleaver, and which works at the symbol level;

a high level deinterleaver that is responsive to a set of high level deinterleaving signals, that is controlled by a set of high level deinterleaving parameters, and which works at the codeword level; and

a low level deinterleaver that is responsive to a set of low level deinterleaving signals provided by the high level deinterleaver, and which works at the symbol level.