Overlapped multiplexing-based decoding method and device, and modulation and demodulation method and system
In an overlapped multiplexing-based decoding method and device, and modulation and demodulation method and system provided in this application, a convolution operation with a header and without a tail is split into group operations with both a header and a tail by using a slide group decoding scheme and based on association between adjacent symbols in an OvXDM system, and then each group of sequences is decoded by using a corresponding decoding algorithm.
1. An overlapped multiplexing-based decoding method, comprising:
step 1: setting a group sequence length based on a length of a multiplexing waveform in a received signal, and grouping receive sequences in the received signal;
step 2: converting a multiplexing waveform coefficient into a matrix form based on the group sequence length;
step 3: decoding a receive sequence of a current group by using a preset algorithm, to obtain a transmit sequence of the current group in an original signal;
step 4: if there is known information in the receive sequence of the current group, removing the known information; otherwise, proceeding to step 5;
step 5: sliding the receive sequence backward, and repeating step 3 and step 4, until all groups are decoded; and
step 6: outputting a decoding result after all the groups are decoded.
2. The method according to claim 1 , wherein when the multiplexing waveform coefficient is converted into the matrix form based on the group sequence length, a representation is:
[
h
0
0
0
0
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h
1
h
0
0
0
0
h
2
h
1
h
0
0
0
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0
0
h
K
-
1
h
K
-
2
⋯
h
0
0
0
h
K
-
1
h
K
-
2
⋯
h
0
]
M
×
M
wherein h is the multiplexing waveform coefficient, and M is the group sequence length.
3. The method according to claim 1 , wherein the preset algorithm is a gradient algorithm, a least squares algorithm, a steepest descent algorithm, a conjugate gradient algorithm, an accelerated conjugate gradient algorithm, or an accelerated Chebyshev algorithm.
4. The method according to claim 1 , wherein when the receive sequence of the current group is decoded by using the preset algorithm, the method further comprises: storing a non-variable in the preset algorithm, and calling the non-variable during decoding.
5. The method according to claim 4 , wherein the preset algorithm is a least squares algorithm, and the non-variable is (H T ×H) −1 ×H T , wherein H is a matrix obtained after conversion of the multiplexing waveform coefficient.
6. An overlapped multiplexing-based decoding device, comprising:
a grouping module, configured to set a group sequence length based on a length of a multiplexing waveform in a received signal, and group receive sequences in the received signal;
a conversion module, configured to convert a multiplexing waveform coefficient into a matrix form based on the group sequence length;
a decoding module, configured to decode a receive sequence of a current group by using a preset algorithm, to obtain a transmit sequence of the current group in an original signal;
a known information removal module, configured to: when there is known information in the receive sequence of the current group, remove the known information;
a sliding module, configured to slide the receive sequence backward, and control the decoding module and the known information removal module to repeatedly perform a decoding step, until all groups are decoded; and
an output module, configured to output a decoding result after all the groups are decoded.
7. The device according to claim 6 , wherein when the multiplexing waveform coefficient is converted into the matrix form based on the group sequence length, a representation is:
[
h
0
0
0
0
0
h
1
h
0
0
0
0
h
2
h
1
h
0
0
0
⋮
⋮
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0
0
h
K
-
1
h
K
-
2
⋯
h
0
0
0
h
K
-
1
h
K
-
2
⋯
h
0
]
M
×
M
wherein h is the multiplexing waveform coefficient, and M is the group sequence length.
8. The device according to claim 6 , wherein the preset algorithm is a gradient algorithm, a least squares algorithm, a steepest descent algorithm, a conjugate gradient algorithm, an accelerated conjugate gradient algorithm, or an accelerated Chebyshev algorithm.
9. The device according to claim 6 , further comprising a storage module, configured to store a non-variable in the preset algorithm, and the decoding module calls the non-variable during decoding.
10. The device according to claim 9 , wherein the preset algorithm is a least squares algorithm, and the non-variable is (H T ×H) −1 ×H T , wherein H is a matrix obtained after conversion of the multiplexing waveform coefficient.
11. An overlapped multiplexing-based modulation and demodulation method, comprising a modulation step and a demodulation step, wherein
the modulation step comprises:
generating an initial envelope waveform;
shifting the initial envelope waveform in a corresponding domain at a shift interval based on a quantity of times of overlapped multiplexing, to obtain shifted envelope waveforms at fixed intervals;
converting an input digital signal sequence into a signal symbol sequence represented by using positive and negative symbols;
multiplying the signal symbol sequence by offset shifted envelope waveforms at fixed intervals, to obtain modulated envelope waveforms;
superimposing the modulated envelope waveforms in the corresponding domain, to obtain a complex modulated envelope waveform carrying the digital signal sequence; and
transmitting the complex modulated envelope waveform; and
the decoding method used in the demodulation step comprises:
step 1: setting a group sequence length based on a length of a multiplexing waveform in a received signal, and grouping receive sequences in the received signal;
step 2: converting a multiplexing waveform coefficient into a matrix form based on the group sequence length;
step 3: decoding a receive sequence of a current group by using a preset algorithm, to obtain a transmit sequence of the current group in an original signal;
step 4: if there is known information in the receive sequence of the current group, removing the known information; otherwise, proceeding to step 5;
step 5: sliding the receive sequence backward, and repeating step 3 and step 4, until all groups are decoded; and
step 6: outputting a decoding result after all the groups are decoded.
12. The overlapped multiplexing-based modulation and demodulation method according to claim 11 , wherein when the multiplexing waveform coefficient is converted into the matrix form based on the group sequence length, a representation is:
[
h
0
0
0
0
0
h
1
h
0
0
0
0
h
2
h
1
h
0
0
0
⋮
⋮
⋮
0
0
h
K
-
1
h
K
-
2
⋯
h
0
0
0
h
K
-
1
h
K
-
2
⋯
h
0
]
M
×
M
wherein h is the multiplexing waveform coefficient, and M is the group sequence length.
13. The overlapped multiplexing-based modulation and demodulation method according to claim 11 , wherein the preset algorithm is a gradient algorithm, a least squares algorithm, a steepest descent algorithm, a conjugate gradient algorithm, an accelerated conjugate gradient algorithm, or an accelerated Chebyshev algorithm.
14. The overlapped multiplexing-based modulation and demodulation method according to claim 11 , wherein when the receive sequence of the current group is decoded by using the preset algorithm, the method further comprises: storing a non-variable in the preset algorithm, and calling the non-variable during decoding.
15. The overlapped multiplexing-based modulation and demodulation method according to claim 14 , wherein the preset algorithm is a least squares algorithm, and the non-variable is (H T ×H) −1 ×H T , wherein H is a matrix obtained after conversion of the multiplexing waveform coefficient.