Area and power efficient architectures of time deinterleaver for ISDB-T receivers
View Patent ↗A method and apparatus for de-interleaving interleaved data in a deinterleaver memory in an Orthogonal Frequency Division Multiplexing (OFDM) based Integrated Services Digital Broadcasting Terrestrial (ISDB-T) receiver. In different embodiments, the apparatus comprises of a OFDM symbol counter along with a divider or a buffer pointer RAM with circular pointer logic, a first lookup table to obtain delay buffer size and interleaving lengths for a given OFDM transmission layer, and a second lookup table to obtain buffer base address and interleaving lengths for a given OFDM transmission layer.
1. An apparatus for de-interleaving interleaved data in an Orthogonal Frequency Division Multiplexing (OFDM) based receiver, said apparatus comprising:
a deinterleaver memory;
a buffer pointer random access memory (RAM) adapted to store buffer pointer values, said buffer pointer RAM comprising circular pointer increment logic;
a first lookup table in said deinterleaver memory for obtaining delay buffer sizes for various carriers and interleaving lengths for a given OFDM transmission layer; and
a second lookup table in said deinterleaver memory for obtaining buffer base addresses for various carriers and interleaving lengths for a given OFDM transmission layer,
wherein a buffer pointer RAM size is chosen based on uninterrupted television viewing time on a particular channel.
2. The apparatus of claim 1 , wherein said buffer pointer RAM comprises a 95×11 RAM.
3. The apparatus of claim 1 , wherein the first and second lookup tables are implemented as a read-only memory (ROM).
4. The apparatus of claim 1 , wherein the first and second lookup tables are implemented using dynamic arithmetic calculations.
5. The apparatus of claim 1 , wherein said receiver comprises a mobile television receiver.
6. The apparatus of claim 1 , wherein said receiver comprises an Integrated Services Digital Broadcasting Terrestrial (ISDB-T) receiver.
7. A method of de-interleaving interleaved data on a deinterleaver memory component in an Orthogonal Frequency Division Multiplexing (OFDM) based receiver using a buffer pointer random access memory (RAM) and circular pointer logic, a first lookup table to obtain delay buffer sizes for various carriers and interleaving lengths for a given OFDM transmission layer, and a second lookup table to obtain buffer base address and interleaving lengths for a given OFDM transmission layer, said method comprising:
reading a pointer value for a corresponding carrier from said buffer pointer RAM;
incrementing the read pointer value;
retrieving a buffer size value for said corresponding carrier from said first lookup table;
calculating intra buffer offset for a carrier by comparing said buffer size with said incremented pointer value;
retrieving a buffer base address value for corresponding carrier from said second lookup table;
adding calculated intra buffer offset to said buffer base address to calculate a memory address to store carrier data bits of the corresponding carrier; and
storing said carrier data bits at said calculated memory address.
8. The method of claim 7 , wherein said buffer pointer RAM comprises 96 stored pointer values.
9. The method of claim 7 , wherein the first and second lookup tables are implemented as a read-only memory (ROM).
10. The method of claim 7 , wherein the first and second lookup tables are implemented using dynamic arithmetic calculations.
11. The method of claim 7 , wherein the delay buffer sizes and buffer base addresses are obtained for various carriers and interleaving lengths for a given OFDM transmission layer from the first and second lookup table respectively.
12. The method of claim 7 , wherein said receiver comprises a mobile television receiver.
13. The method of claim 7 , wherein said receiver comprises an Integrated Services Digital Broadcasting Terrestrial (ISDB-T) receiver.
14. A system for de-interleaving interleaved data on a deinterleaver memory component in an Orthogonal Frequency Division Multiplexing (OFDM) based receiver using a buffer pointer random access memory (RAM) and circular pointer logic, a first lookup table to obtain delay buffer sizes for various carriers and interleaving lengths for a given OFDM transmission layer, and a second lookup table to obtain buffer base address and interleaving lengths for a given OFDM transmission layer, said system comprising:
means for reading a pointer value for a corresponding carrier from said buffer pointer RAM;
means for incrementing the read pointer value;
means for retrieving a buffer size value for said corresponding carrier from said first lookup table;
means for calculating intra buffer offset for a carrier by comparing said buffer size with said incremented pointer value;
means for retrieving a buffer base address value for corresponding carrier from said second lookup table;
means for adding calculated intra buffer offset to said buffer base address to calculate a memory address to store carrier data bits of the corresponding carrier; and
means for storing said carrier data bits at said calculated memory address.
15. The system of claim 14 , wherein said buffer pointer RAM comprises 96 stored pointer values.
16. The system of claim 14 , wherein the first and second lookup tables are implemented as a read-only memory (ROM).
17. The system of claim 14 , wherein the first and second lookup tables are implemented using dynamic arithmetic calculations.
18. The system of claim 14 , wherein the delay buffer sizes and buffer base addresses are obtained for various carriers and interleaving lengths for a given OFDM transmission layer from the first and second lookup table respectively.
19. The system of claim 14 , wherein said receiver comprises a mobile television receiver.
20. The system of claim 14 , wherein said receiver comprises an Integrated Services Digital Broadcasting Terrestrial (ISDB-T) receiver.