High-performance LDPC coding for digital communications in a multiple-input, multiple-output environment
Transceiver circuitry for use in a multiple-input, multiple-output (MIMO), orthogonal frequency-division multiplexing (OFDM), communications environment, is disclosed. Error correction coding according to a fixed-block size code, such as low density parity check (LDPC) coding, is implemented. A specific LDPC code with excellent error rate performance is disclosed.
1. A method of transmitting coded communications comprising the steps of:
receiving a block of payload data;
applying a low density parity check (LDPC) code to the block of payload data to encode the received block of payload data into a codeword, the LDPC code represented by a macro matrix arranged in block rows and block columns and in which each entry corresponds to either an 81×81 zero-valued matrix or corresponds to an 81×81 circularly shifted identity matrix to define a parity check matrix, wherein the columns of the parity check matrix correspond to input nodes and the rows of the parity check matrix correspond to parity check sums, wherein the macro matrix is represented by an ordering of rows and columns from an arrangement of:
57
50
11
50
79
3
28
0
55
7
30
24
37
56
14
62
53
53
3
35
40
20
66
22
28
0
8
42
50
8
69
79
79
56
52
65
38
57
72
27
64
14
52
30
32
45
70
0
77
9
2
56
57
35
12
24
61
60
27
51
16
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
in which numerical values correspond to the shifts of the identity diagonal in each of the circularly shifted identity matrices, and in which blank matrix entries correspond to a zero-valued matrix;
modulating at least one carrier signal to produce a signal stream having symbols corresponding to the codeword; and
transmitting the signal stream over a communications channel.
2. The method of claim 1 , further comprising:
separating the codeword into a plurality of datastreams;
wherein the modulating step comprises:
modulating at least one carrier signal to produce each of a plurality of signal streams having symbols corresponding to an associated encoded datastream;
and wherein the transmitting step comprises:
transmitting the plurality of signal streams over a communications channel.
3. The method of claim 1 , wherein the modulating step modulates a plurality of subchannel carrier signals for each of the plurality of signal streams.
4. A transceiver for transmitting an encoded signal stream, comprising:
encoder circuitry, for encoding payload data according to a low density parity check (LDPC) code to the block of payload data to encode the received block of payload data into a codeword, the LDPC code represented by a macro matrix arranged in block rows and block columns and in which each entry corresponds to an 81×81 zero-valued matrix or corresponds to an 81×81 circularly shifted identity matrix to define a parity check matrix, wherein the columns of the parity check matrix correspond to input nodes and the rows of the parity check matrix correspond to parity check sums, wherein the macro matrix is represented by an ordering of rows and columns from an arrangement of:
57
50
11
50
79
1
0
3
28
0
55
7
0
0
30
24
37
56
14
0
0
62
53
53
3
35
0
0
40
20
66
22
28
0
0
0
8
42
50
8
0
0
69
79
79
56
52
0
0
0
65
38
57
72
27
0
0
64
14
52
30
32
0
0
45
70
0
77
9
0
0
2
56
57
35
12
0
0
24
61
60
27
51
16
1
0
in which numerical values correspond to the shifts of the identity diagonal in each of the circularly shifted identity matrices, and in which blank matrix entries correspond to a zero-valued matrix;
a modulator, for modulating at least one carrier signal to produce a signal stream having symbols corresponding to the codeword; and
circuitry, for transmitting the modulated signal stream over a communications channel.
5. The transceiver of claim 4 , further comprising:
parser circuitry for separating the encoded codeword into a plurality of datastreams; and
a plurality, of antennae;
wherein the modulator modulates at least one carrier signal according to each of the plurality of datastreams;
and wherein the transmitting circuitry comprises:
RF circuitry, for transmitting, modulated signals for each of the multiple datastreams over a corresponding one of the plurality of antennae, the modulated signals corresponding to codewords for the respective datastreams generated by the encoder circuitry.
6. The transceiver of claim 5 , wherein the modulator comprises:
modulation circuitry, for modulating a plurality of subchannel carriers for each of the multiple datastreams according to the codewords.
7. A method of decoding coded communications, comprising the steps of:
demodulating a received signal; to produce a datastream;
decoding the datastream with an error correcting code by applying the error correcting code to sequences of codewords in the datastream wherein the error correcting code is a low density parity check (LDPC) represented by a macro matrix arranged in block rows and block columns and in which each entry corresponds to an 81×81 zero-valued matrix or corresponds to an 81×81 circularly shifted identity matrix to define a parity check matrix, wherein the columns of the parity check matrix correspond to input nodes and the rows of the parity check matrix correspond to parity check sums, wherein the macro matrix is represented by an ordering of rows and columns from an arrangement of:
57
50
11
50
79
1
0
3
28
0
55
7
0
0
30
24
37
56
14
0
0
62
53
53
3
35
0
0
40
20
66
22
28
0
0
0
8
42
50
8
0
0
69
79
79
56
52
0
0
0
65
38
57
72
27
0
0
64
14
52
30
32
0
0
45
70
0
77
9
0
0
2
56
57
35
12
0
0
24
61
60
27
51
16
1
0
in which numerical values correspond to the shifts of the identity diagonal in each of the circularly shifted identity matrices, and in which blank matrix entries correspond to a zero-valued matrix; and
forwarding the decoded datastream to a destination.
8. The method of claim 7 , wherein the signal is received at each of a plurality of antennae;
wherein the demodulating, step comprises:
demodulating a signal received at each of a plurality, of antennae; to produce a plurality of demodulated datastreams;
and further comprising after the demodulating step:
combining the plurality of demodulated datastreams into a datastream, arranged as a sequence of codewords, each codeword including information and parity portions.
9. A transceiver for receiving and decoding an encoded signal stream, comprising:
a demodulator, for demodulating at least one carrier signal to produce a signal stream having symbols corresponding to codewords; and
decoder circuitry, for decoding payload data from the codewords according to a low density parity check (LDPC) code, the LDPC code represented by a macro matrix arranged in block rows and block columns and in which each entry corresponds to either an 81×81 zero-valued matrix or corresponds to an 81×81 circularly shifted identity matrix to define a parity check matrix, wherein the columns of the parity check matrix correspond to input nodes and the rows of the parity check matrix correspond to parity check sums, wherein the macro matrix is represented by an ordering of rows and columns from an arrangement of:
57
50
11
50
79
1
0
3
28
0
55
7
0
0
30
24
37
56
14
0
0
62
53
53
3
35
0
0
40
20
66
22
28
0
0
0
8
42
50
8
0
0
69
79
79
56
52
0
0
0
65
38
57
72
27
0
0
64
14
52
30
32
0
0
45
70
0
77
9
0
0
2
56
57
35
12
0
0
24
61
60
27
51
16
1
0
in which numerical values correspond to the shifts of the identity diagonal in each of the circularly shifted identity matrices, and in which blank matrix entries correspond to a zero-valued matrix.
10. The transceiver of claim 9 , further comprising:
interface circuitry, coupled to a plurality of antennae to receive signals from each of the antennae;
wherein the demodulator comprises:
demodulating circuitry for demodulating a signal received from each of the plurality of antennae; to produce a plurality of demodulated datastreams;
and further comprising;
circuitry, coupled to the demodulating circuitry, for combining the plurality of demodulated datastreams into the datastream applied to the decoder circuitry, the datastream arranged as a sequence of codewords, each codeword including information and parity portions.