Method and apparatus for interleaving in a wireless communication system
View Patent ↗The method and apparatus in accordance with the present invention receives bits, writes the bits row-by-row in a matrix, reads the bits column-by-column from the matrix, groups and rotates the bits read column-by-column from the matrix so as to evenly separate the bits in position, frequency, space over one symbol period.
1. A method to process transmission data using a processor, comprising:
a) receiving bits;
b) writing said received bits row-by-row in a matrix;
c) reading said bits written row-by-row in said matrix column-by-column;
d) grouping a pre-determined number of said bits read column-by-column to form subsymbols;
e) grouping said subsymbols to form groups of subsymbols;
f) rotating said groups of subsymbols to form rotated groups of subsymbols;
g) transmitting said rotated groups of subsymbols over transmit paths using antennas;
wherein adjacent received bits in step a) are separated over frequency, position, and multiple streams when transmitted.
2. The method of claim 1 , wherein adjacent bits received in step a) are separated over frequency, position, and multiple streams, and over one symbol period when transmitted.
3. The method of claim 1 , wherein a size of said matrix (N′ CBPS ) is defined as:
N′ CBPS =N SS ×K×B;
wherein,
N SS is the number of streams;
K is the number of tones/stream and
B is the number of bits/tone.
4. The method of claim 1 , wherein a number of columns (r) in said matrix is greater than or equal to 17 and less than or equal to 47.
5. The method of claim 1 , wherein a number of columns (r) in said matrix is 24.
6. The method of claim 1 , step (d) further comprising the step of mapping adjacent received bits onto nonadjacent tones and non-adjacent streams using a first permutation.
7. The method of claim 6 , step (d) further comprising mapping adjacent received bits alternately onto less and more significant bits of a constellation using a second permutation.
8. The method of claim 7 , wherein said first permutation is defined as:
i
=
N
CBPS
′
r
(
k
mod
r
)
+
⌊
k
r
⌋
where
k
=
0
,
1
,
…
N
CBPS
′
-
1
;
and said second permutation is defined as:
j
=
s
⌊
i
s
⌋
+
(
i
+
N
CBPS
′
-
⌊
ri
N
CBPS
′
⌋
)
mod
s
where
i
=
0
,
1
…
N
CBPS
′
-
1
;
wherein,
r is the number of columns in the matrix;
k denotes the index of the bit before the first permutation;
i denotes the index after the first but before the second permutation;
j denotes the index after the second permutation; and
N′ CBPS is the number of coded bits per sub carrier.
9. The method of claim 1 , wherein at least four tones and one stream separation is introduced between adjacent bits received in step a) and transmitted in step g).
10. The method of claim 1 , wherein successive bits are modulated onto alternate streams.
11. The method of claim 1 , wherein in step d) said pre-determined number of bits is the number of bits per tone.
12. The method of claim 1 , wherein rotating said group of sub-symbols in step f) increases separation between adjacent bits.
13. A system to process transmission data comprising:
a) means for receiving bits;
b) means for writing said received bits row-by-row in a matrix;
c) means for reading said bits written row-by-row in said matrix column-by-column;
d) means for grouping a pre-determined number of said bits read column-by-column to form subsymbols;
e) means for grouping said subsymbols to form groups of subsymbols;
f) means for rotating said groups of subsymbols to form rotated groups of subsymbols;
g) means for transmitting said rotated groups of subsymbols over transmit paths;
wherein adjacent received bits are separated over frequency, position, and multiple streams when transmitted.
14. The system of claim 13 , wherein adjacent bits received are separated over frequency, position, and multiple streams, and over one symbol period when transmitted.
15. The system of claim 13 , wherein a size of said matrix (N′ CBPS ) is defined as:
N′ CBPS =N SS ×K×B;
wherein,
N SS is the number of streams;
K is the number of tones/stream and
B is the number of bits/tone.
16. The system of claim 13 , wherein a number of columns (r) in said matrix is greater than or equal to 17 and less than or equal to 47.
17. The system of claim 13 , wherein a number of columns (r) in said matrix is 24.
18. The system of claim 13 , further comprising means for introducing at least four tones and one stream separation between adjacent bits received when transmitted.
19. A system to process transmission data comprising:
a) a hardware module configured to receive bits;
b) a hardware module configured to write said received bits row-by-row in a matrix;
c) a hardware module configured to read said bits written row-by-row in said matrix column-by-column;
d) a hardware module configured to group a pre-determined number of said bits read column-by-column to form subsymbols;
e) a hardware module configured to group said subsymbols to form groups of subsymbols;
f) a hardware module configured to rotate said groups of subsymbols to form rotated groups of subsymbols;
g) a hardware module configured to transmit said rotated groups of subsymbols over transmit paths;
wherein adjacent received bits are separated over frequency, position, and multiple streams when transmitted.
20. The system of claim 19 , wherein adjacent received bits are separated over frequency, position, and multiple streams, and over one symbol period when transmitted.