Interleaving scheme for an LDPC coded 32 APSK system
AssigneeAvailink, Inc.
InventorsJuntan Zhang, Zhiyong Wu, Peng Gao, Fengwen Sun
Life of this patent
Estimating the term…
Abstract
An approach is provided for interleaving low density parity check (LDPC) encoded bits in 32APSK modulation systems. By assigning the bits determining modulation symbols based on different bit degrees, one can efficiently find the desirable tradeoff between error performance and error floor provided by the LDPC codes in use.
Claims2
A digital communications transmitter, including a processor, interleaving LDPC encoded bits in a 32APSK modulation system based on a rule:
- b
- ~
- i
- +
- j
- =
- b
- (
- i
- 5
- +
- 32
- ×
- N
- offset
- +
- 3072
- ×
- j
- )
-
- modN
- ldpc_bits
- -
- (
- i
- 5
- )
-
- mod
-
-
- 256
- +
- (
- i
- 5
-
- mod
-
-
- 8
- )
- ×
- 32
- +
- ⌊
- i
- 40
- ⌋
-
- mod
-
-
- 32
- for iε{i|0≦i≦Nldpc—bits−1, and i mod 5=0} and j=0, 1, 2, 3, 4, where └x┘ is the floor function which returns the largest integer that is less than or equal to x, Nldpc—bits=15360 is the codeword length of the LDPC code in use, and the offset values NOffset for different code rates are defined as:
- Rate
- Noffset
- 3/4
- 72
- 4/5
- 80
- 5/6
- 120
- 13/15
- 160
- 9/10
- 192.
A digital communications receiver employing an LDPC decoder for decoding interleaved LDPC encoded bits in a 32ASPK modulation system based on a rule:
- b
- ~
- i
- +
- j
- =
- b
- (
- i
- 5
- +
- 32
- ×
- N
- offset
- +
- 3072
- ×
- j
- )
-
- modN
- ldpc_bits
- -
- (
- i
- 5
- )
-
- mod
-
-
- 256
- +
- (
- i
- 5
-
- mod
-
-
- 8
- )
- ×
- 32
- +
- ⌊
- i
- 40
- ⌋
-
- mod
-
-
- 32
- for iε{i|0≦i≦Nldpc—bits−1, and i mod 5=0} and j=0, 1, 2, 3, 4, where └x┘ is the floor function which returns the largest integer that is less than or equal to x, Nldpc—bits=15360 is the codeword length of the LDPC code in use, and the offset values NOffset for different code rates are defined as:
- Rate
- Noffset
- 3/4
- 72
- 4/5
- 80
- 5/6
- 120
- 13/15
- 160
- 9/10
- 192.
Dependencies are inferred from the claim text.