Method and apparatus for preserving deinterleaving erasure information of block interleaved coded signal
View Patent ↗Erasure information associated with a received group of encoded and interleaved data in a digital video broadcasting system is stored in a much compacted form. An erasure flag and an address of a last byte associated with the received group of encoded and interleaved data (a record) encapsulated in an MPE-FEC column will be stored in an erasure table. All bytes in the column preceding the last byte of the record will have the same erasure flag as the last byte. Erasure information deinterleaver 524 reads out the content of the erasure table (i.e., the erasure information) in a de-interleaving fashion; and the de-interleaved erasure information 525 are then applied with the de-interleaved coded signals 511 to an FEC decoder 526 to enhance the FEC decoding performance.
1. A method for preserving erasure information in a block interleaved coding system comprising:
receiving a plurality of groups of coded data;
obtaining erasure information associated with a first one of the plurality of groups of coded data;
comparing the erasure information with a reference value to determine if a match exists;
in the event that no match exists:
generating a first record including a first address and the erasure information; and
storing the first record at a location in an erasure table.
2. The method of claim 1 , wherein each one of the plurality of groups of coded data is a transport stream (TS) packet including a header having a plurality of fields and a payload in accordance with an MPEG standard.
3. The method of claim 2 , wherein the erasure information is one of the plurality of fields in the header of the TS packet.
4. The method of claim 1 , wherein the erasure information comprises one or more bits.
5. The method of claim 4 further comprising updating the reference value by replacing it with the erasure information.
6. The method of claim 1 further comprising:
determining if an end of the column is reached;
generating a new record if the end of the column is reached.
7. The method of claim 1 , wherein the erasure table comprises a storage memory module having a matrix of N by C storage cells, wherein N and C are integers.
8. The method of claim 7 , wherein the storage memory module is a static random access memory (SRAM).
9. The method of claim 7 , wherein C corresponds to a number of columns in an MPE-FEC frame specified in a DVB-H standard.
10. The method of claim 7 , wherein N corresponds to a positive integer of a division result of a number of rows in the MPE-FEC frame by a payload length of a transport stream (TS) packet.
11. The method of claim 10 , wherein the number of rows in the MPE-FEC frame is one of decimal values 256, 512, 768, or 1024.
12. The method of claim 10 , wherein N is equal to or less than eight (8).
13. The method of claim 1 further comprising retrieving erasure information from the erasure table.
14. The method of claim 13 , wherein the retrieving of erasure information comprises:
accessing a record of a column in the erasure table, the record including a row index;
retrieving an erasure information from the record if the row index is smaller than an address field accessed during a preceding access;
accessing a next record if the row index is not smaller than the address field accessed during the preceding access; and
repeating the retrieving and accessing operations until a last record associated with a last row is accessed and the associated erasure information is retrieved.
15. The decoder of claim 1 , wherein the first address is an address of a last byte of the first one of the plurality of groups of encoded data in a column.
16. A decoder comprising:
a block deinterleaver adapted to de-interleave a plurality of groups of encoded data and output a plurality of blocks of de-interleaved encoded data;
an erasure detector adapted to:
receive the plurality of groups of encoded data;
obtain erasure information of a first one of the plurality of groups of encoded data; and
generate a first record including a first address and the erasure information in response to the obtained erasure information; and
an erasure table adapted to store the first record.
17. The decoder of claim 16 , wherein each one of the plurality of groups of encoded data is a transport stream (TS) packet having a header and a payload in accordance with an MPEG standard.
18. The decoder of claim 16 , wherein the erasure detector is adapted to generate a new record-if an end of column is reached.
19. The decoder of claim 16 , wherein the erasure detector parses an indicator field and determines an address of a last-byte associated with a group of encoded data in a column of an MPE-FEC frame.
20. The decoder of claim 19 , wherein the indicator field is a binary flag adapted to represent an erasure information for all encoded data encapsulated in the group, the group being identifiable by the address of the last byte in the column of the MPE-FEC frame.
21. The decoder of claims 19 wherein the erasure detector generates a record comprising the erasure information and the address of the last byte of the associated group in the column of the MPE-FEC frame.
22. The decoder of 21 , wherein the record is stored in the erasure table.
23. The decoder of claim 16 , wherein the erasure table comprises a storage memory module having a matrix of N by C of memory cells, wherein N and C are integers.
24. The decoder of claim 23 , wherein C corresponds to a number of columns in an MPE-FEC frame specified in a DVB-H standard.
25. The decoder of claim 23 , wherein N corresponds to an integer of a division result of a number of rows in the MPE-FEC frame by a payload length of a transport stream packet.
26. The decoder of claim 25 , wherein the number of rows is one of decimal values 256, 512, 768, or 1024.
27. The decoder of claim 16 , wherein the erasure table is a static random access memory (SRAM).
28. The decoder of claim 16 further comprising:
an erasure information deinterleaver adapted to output a plurality of de-interleaved erasure information; and
an FEC decoder adapted to receive the plurality of blocks of de-interleaved encoded data and the plurality of de-interleaved erasure information and output a stream of decoded data.
29. The decoder of claim 28 , wherein the erasure information deinterleaver is adapted to:
access a record of a column in the erasure table, the record including a row index;
retrieve an erasure information from the record if the row index is smaller than an address field accessed during a preceding access;
access a next record if the row index is not smaller than the address field accessed during the preceding access; and
repeat the retrieving and accessing operations until a last record associated with a last row is accessed and the associated erasure information is retrieved.
30. The method of claim 16 wherein the first address is an address of a last byte of the first one of the plurality of groups of coded data in a column.