CN109756275B - Demodulation method and demodulation device - Google Patents
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Abstract
A demodulation method and a demodulation device comprise: dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8 Quadrature Amplitude Modulation (QAM) modulated input signal; and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the log-likelihood ratio (LLR) of the information bit according to an LLR calculation formula corresponding to the region to which the input signal belongs. The method reduces the introduction of errors, reduces the performance loss of soft decoding and simplifies the computational complexity.
Description
Technical Field
The present disclosure relates to, but not limited to, digital signal processing, and more particularly, to a demodulation method and a demodulation apparatus.
Background
With the development of optical communication technology, the capacity of single-channel optical communication systems has been developed from 10 gigabytes per second (Gb/s) in the 90 s to 100Gb/s in 2010. While a global mainstream manufacturer promotes the global deployment of a 100Gb/s system, the pre-research work of 400Gb/s and 1Tb/s is actively carried out; among them, high-order Modulation is an important means for bringing high symbol utilization rate, Quadrature Amplitude Modulation (QAM) becomes a hot Modulation scheme of the next generation optical communication system, and the focus is to design a Modulation and demodulation method with low complexity.
The previous application with the application number of CN105991508A provides an 8QAM modulation method and a system thereof, provides a new 8QAM bit constellation point mapping, increases the Euclidean distance between constellation points, and improves the transmission performance; this scheme simplifies the modulation method but does not provide an efficient demodulation method.
The prior application with the application number of CN103916216A proposes a multilevel quasi-cyclic low-density parity check (QC-LDPC) coding modulation method based on an 8QAM modulation scheme in an optical communication system, and proposes to use a set partitioning scheme to encode a first bit and a second bit with different code rates, so as to achieve lower computational complexity and higher Net Coding Gain (NCG); meanwhile, different calculation methods are adopted for three bits when the Log-Likelihood ratio (LLR) is calculated by the scheme, and the calculation complexity of the last two bits is reduced.
Compared with the calculation method based on the maximum likelihood, the LLR calculation method has the advantages that errors are introduced due to simplified calculation, and the large soft decoding performance loss is caused.
Disclosure of Invention
The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.
Embodiments of the present invention provide a demodulation method and a demodulation apparatus, which can reduce the introduction of errors and reduce the performance loss of soft decoding.
The embodiment of the invention provides a demodulation method, which comprises the following steps:
dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8 Quadrature Amplitude Modulation (QAM) modulated input signal;
and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs.
Optionally, the average energy of the received 8QAM modulated input signal is normalized to a210, noise power σ2The time constellation point mapping mode comprises the following steps:
wherein i is a positive integer.
Optionally, for a first information bit of the input signal, dividing the constellation diagram of the information bit into one or more regions according to a preset policy includes:
dividing a part of a constellation diagram virtual coordinate of the information bit, which is greater than or equal to 3, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is greater than or equal to-3 and less than-1, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is less than or equal to-3, into a region;
for a second information bit of the input signal, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram with the real coordinate of the information bit more than or equal to 3 into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-3 and less than-1, into a region;
and dividing the part of the constellation diagram with the real coordinate of the information bit less than or equal to-3 into a region.
For a third information bit of the input signal, dividing the constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram with the real coordinate of the information bit more than or equal to 3 into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-3 and less than-1, into a region;
and dividing the part of the constellation diagram with the real coordinate of the information bit less than or equal to-3 into a region.
Optionally, for each information bit, the region to which the input signal belongs is determined according to a preset policy, and the LLR of the information bit is calculated according to the log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs:
for the first information bit of the input signal, judging the region to which the input signal belongs according to the imaginary coordinates of the input signal, wherein the LLR calculation formula comprises:
for the second information bit of the input signal, judging the region to which the input signal belongs according to the real coordinates of the input signal, wherein the LLR calculation formula comprises:
for the third information bit of the input signal, judging the region to which the input signal belongs according to the real coordinates of the input signal, wherein the LLR calculation formula comprises the following steps:
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
Optionally, the average energy of the received 8QAM modulated input signal is normalized to
Noise power of sigma2The time constellation point mapping mode comprises the following steps:
wherein i is a positive integer.
Optionally, for a first information bit of the input signal, dividing a constellation diagram of the information bit into a region;
for a second information bit of the input signal, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy respectively includes:
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than or equal to
And is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than
Is a region;
for a third information bit of the input signal, the dividing the constellation diagram of the information bit into one or more regions according to a preset strategy respectively includes:
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than or equal to
And is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than
Is a region;
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
Optionally, for each information bit, determining a region to which the input signal belongs according to a preset policy, and calculating an LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs:
for a first information bit of the input signal, the LLR calculation formula includes:
for a second information bit of the input signal, as a function of the real part of the input signal and the imaginary part of the input signal
And judging the region to which the input signal belongs, wherein the LLR calculation formula comprises the following steps:
for a third information bit of the input signal as a function of the real part of the input signal and the imaginary part of the input signal
And judging the region to which the input signal belongs, wherein the LLR calculation formula comprises the following steps:
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
On the other hand, an embodiment of the present invention further provides a demodulation apparatus, including: the device comprises a dividing unit and a judging and calculating unit; wherein,
the dividing unit is used for: dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8QAM modulated input signal;
the judging and calculating unit is used for: and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs.
In still another aspect, an embodiment of the present invention further provides a computer storage medium, where computer-executable instructions are stored in the computer storage medium, and the computer-executable instructions are used to execute the foregoing demodulation method.
In another aspect, an embodiment of the present invention further provides a terminal, where the terminal includes: a memory and a processor; wherein,
the processor is configured to execute program instructions in the memory;
the program instructions read on the processor to perform the following operations:
dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8QAM modulated input signal;
and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs.
Compared with the related art, the technical scheme of the application comprises the following steps: dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8 Quadrature Amplitude Modulation (QAM) modulated input signal; and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs. The method reduces the introduction of errors and reduces the performance loss of soft decoding.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.
FIG. 1 is a flow chart of a demodulation method according to an embodiment of the present invention;
FIG. 2 is a constellation point map of an input signal according to an alternative embodiment of the present invention;
FIG. 3 is a schematic diagram of zoning an alternative embodiment of the present invention;
FIG. 4 is a schematic view of a partition according to another alternative embodiment of the present invention;
FIG. 5 is a schematic illustration of zoning in accordance with yet another alternative embodiment of the present invention;
fig. 6 is a constellation point map of an input signal according to another alternative embodiment of the present invention;
FIG. 7 is a schematic illustration of zoning another alternative embodiment of the present invention;
FIG. 8 is a schematic view of a further alternative embodiment of the present invention for zoning;
FIG. 9 is a graph of performance loss versus demodulation method;
fig. 10 is a block diagram of a demodulation apparatus according to the embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.
The steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.
Fig. 1 is a flowchart of a demodulation method according to an embodiment of the present invention, as shown in fig. 1, including:
the input signals of the embodiment of the invention can comprise two types; a first input signal is illustrated below, fig. 2 is a constellation point mapping diagram of an input signal according to an alternative embodiment of the present invention, and as shown in fig. 2, an embodiment of the present invention normalizes average energy of a received 8QAM modulated input signal to a210, noise power σ2The time constellation point mapping mode comprises the following steps:
wherein i is a positive integer.
It should be noted that, the embodiments of the present invention may adjust the constellation point mapping of the input signal, including but not limited to adjusting by using an adjusting method known to those skilled in the art; for example, scaling, adjustment, mirroring, information bit order conversion, and other processing are performed, and the constellation point mapping processed in the above manner is still applicable to the embodiment of the present invention, and only the corresponding processing is performed when the LLR is calculated.
Fig. 3 is a schematic diagram of region division according to an alternative embodiment of the present invention, and as shown in fig. 3, for a first information bit of the input signal shown in fig. 3, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram virtual coordinate of the information bit, which is greater than or equal to 3, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is greater than or equal to-3 and less than-1, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is less than or equal to-3, into a region;
in the figure, the respective regions are distinguished by a dotted line.
Fig. 4 is a schematic diagram of region division according to another alternative embodiment of the present invention, and as shown in fig. 4, for a second information bit of the input signal shown in fig. 4, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram with the real coordinate of the information bit more than or equal to 3 into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-3 and less than-1, into a region;
and dividing the part of the constellation diagram with the real coordinate of the information bit less than or equal to-3 into a region.
Fig. 5 is a schematic diagram of dividing regions according to yet another alternative embodiment of the present invention, and as shown in fig. 5, for a third information bit of the input signal shown in fig. 5, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram with the real coordinate of the information bit more than or equal to 3 into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-3 and less than-1, into a region;
and dividing the part of the constellation diagram with the real coordinate of the information bit less than or equal to-3 into a region.
Optionally, the determining, according to a preset policy, a region to which the input signal belongs for each information bit, and calculating an LLR of the information bit according to an LLR calculation formula corresponding to the region includes:
for the first information bit of the input signal shown in fig. 3, the region to which the input signal belongs is determined according to the imaginary coordinates of the input signal, and the LLR calculation formula includes:
for the second information bit of the input signal shown in fig. 4, the region to which the input signal belongs is determined according to the real coordinates of the input signal, and the LLR calculation formula includes:
for the third information bit of the input signal shown in fig. 5, the region to which the input signal belongs is determined according to the real coordinates of the input signal, and the LLR calculation formula includes:
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
For the second input signal, the following embodiments are used to describe the region division and LLR calculation;
FIG. 6 is a constellation point mapping diagram of an input signal according to another alternative embodiment of the present invention, as shown in FIG. 6, the average energy of the received 8QAM modulated input signal is normalized
Noise power of sigma2Time constellation point mapping methodThe formula comprises:
wherein i is a positive integer.
Optionally, in the embodiment of the present invention, when the first information bit of the input signal shown in fig. 6 is the same as that shown in fig. 6, for the first information bit of the input signal, a constellation diagram of the information bit is divided into an area;
dividing a constellation diagram of information bits into a region;
fig. 7 is a schematic diagram of dividing regions according to yet another alternative embodiment of the present invention, as shown in fig. 7, for a second information bit of the input signal shown in fig. 7, the dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than or equal to
And is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than
Is a region;
fig. 8 is a schematic diagram of region division according to yet another alternative embodiment of the present invention, as shown in fig. 8, for a third information bit shown in fig. 8, the dividing a constellation diagram of the information bit into one or more regions according to a preset policy includes:
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than or equal to
And is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than
Is a region;
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
Optionally, for each information bit, determining a region to which the input signal belongs according to a preset policy, and calculating an LLR of the information bit according to an LLR calculation formula of the corresponding region includes:
for the first information bit of the input signal shown in fig. 6, the LLR calculation formula includes:
for the second information bit of the input signal shown in fig. 7, as a function of the real part of the input signal and the imaginary part of the input signal
And judging the region to which the input signal belongs, wherein the LLR calculation formula comprises the following steps:
for the third information bit of the input signal shown in fig. 8, as a function of the real part of the input signal and the imaginary part of the input signal
And judging the region to which the input signal belongs, wherein the LLR calculation formula comprises the following steps:
according to the embodiment of the invention, the constellation diagram is divided into one or more than one area to be prepared; in addition, if the constellation diagram division region rules of two or more information bits are consistent, the LLRs of two or more information bits can be calculated at the same time, and repeated determination is not required, thereby further reducing the calculation complexity.
In the related art, a maximum a posteriori probability algorithm (Max-Log-MAP) calculation formula based on a maximum approximation in a logarithmic domain is as follows:
wherein s isi(1)、si(0) A set of transmission symbols corresponding to bits bi of 1 and 0.
Compared with the method based on the Max-Log-MAP, the method for calculating the LLR by the demodulation method avoids multiplication operation and reduces calculation complexity on the premise of no obvious performance loss (generally less than 0.2 decibel (db)). Fig. 9 is a performance loss comparison diagram of a demodulation method, as shown in fig. 9, a soft-decision coding and decoding with a code word length of 64800 and a code rate of 5/6 is performed on an input signal according to an embodiment of the present invention, and a curve 1 and a curve 2 respectively represent a performance loss comparison of LLR calculation performed on a first input signal by using a method according to an embodiment of the present invention and a Max-Log-MAP-based method; a curve 3 and a curve 4 respectively represent the comparison of the performance loss of LLR calculation of the second input signal by adopting the method of the embodiment of the invention and the method based on Max-Log-MAP; the performance loss of the embodiment of the invention is less than 0.1db, so that a large number of multiplication operations are avoided, and the calculation complexity is reduced.
Fig. 10 is a block diagram of a demodulation apparatus according to the embodiment of the present invention, and as shown in fig. 10, the demodulation apparatus includes: the device comprises a dividing unit and a judging and calculating unit; wherein,
the dividing unit is used for: dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8QAM modulated input signal;
the judging and calculating unit is used for: and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs.
The embodiment of the invention also provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used for executing the demodulation method.
An embodiment of the present invention further provides a terminal, including: a memory and a processor; wherein,
the processor is configured to execute program instructions in the memory;
the program instructions read on the processor to perform the following operations:
dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8QAM modulated input signal;
and for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs.
It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by a program instructing associated hardware (e.g., a processor) to perform the steps, and the program may be stored in a computer readable storage medium, such as a read only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, each module/unit in the above embodiments may be implemented in hardware, for example, by an integrated circuit to implement its corresponding function, or in software, for example, by a processor executing a program/instruction stored in a memory to implement its corresponding function. The present invention is not limited to any specific form of combination of hardware and software.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. A demodulation method, comprising:
dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8 Quadrature Amplitude Modulation (QAM) modulated input signal;
for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs;
for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating the LLR of the information bit according to the LLR calculation formula corresponding to the region comprises:
for the first information bit of the input signal, judging the region to which the input signal belongs according to the imaginary coordinates of the input signal, wherein the LLR calculation formula comprises:
for the second information bit of the input signal, judging the region to which the input signal belongs according to the real coordinates of the input signal, wherein the LLR calculation formula comprises:
for the third information bit of the input signal, judging the region to which the input signal belongs according to the real coordinates of the input signal, wherein the LLR calculation formula comprises the following steps:
wherein x is the real coordinate of the input signal, and y is the imaginary coordinate of the input signal;
the determining, for each information bit, a region to which an input signal belongs according to a preset policy, and calculating an LLR of the information bit according to an LLR calculation formula corresponding to the region to which the input signal belongs, further includes:
for a first information bit of the input signal, the LLR calculation formula includes:
for a second information bit of the input signal, as a function of the real part of the input signal and the imaginary part of the input signal
And judging the region to which the input signal belongs, wherein the LLR calculation formula comprises the following steps:
for a third information bit of the input signal as a function of the real part of the input signal and the imaginary part of the input signal
And judging the region to which the input signal belongs, wherein the LLR calculation formula comprises the following steps:
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
2. Demodulation method according to claim 1, characterized in that the average energy of the received 8QAM modulated input signal is normalized to a210, noise power σ2The time constellation point mapping mode comprises the following steps:
wherein i is a positive integer.
3. The demodulation method according to claim 2,
for a first information bit of the input signal, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram virtual coordinate of the information bit, which is greater than or equal to 3, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is greater than or equal to-3 and less than-1, into a region;
dividing a part of a constellation diagram virtual coordinate of the information bit, which is less than or equal to-3, into a region;
for a second information bit of the input signal, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram with the real coordinate of the information bit more than or equal to 3 into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-3 and less than-1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is less than or equal to-3, into a region;
for a third information bit of the input signal, dividing the constellation diagram of the information bit into one or more regions according to a preset strategy includes:
dividing a part of a constellation diagram with the real coordinate of the information bit more than or equal to 3 into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to 1 and less than 3, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-1 and less than 1, into a region;
dividing a part of a constellation diagram of information bits, of which the real coordinate is more than or equal to-3 and less than-1, into a region;
and dividing the part of the constellation diagram with the real coordinate of the information bit less than or equal to-3 into a region.
4. The demodulation method of claim 1 wherein the average energy of the received 8QAM modulated input signal is normalized to
Noise power of sigma2The time constellation point mapping mode comprises the following steps:
wherein i is a positive integer.
5. The demodulation method according to claim 4,
for a first information bit of the input signal, dividing a constellation diagram of the information bit into a region;
for a second information bit of the input signal, dividing a constellation diagram of the information bit into one or more regions according to a preset strategy respectively includes:
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than or equal to
And is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than
Is a region;
for a third information bit of the input signal, the dividing the constellation diagram of the information bit into one or more regions according to a preset strategy respectively includes:
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than or equal to
And is greater than
Is a region;
function of real and imaginary coordinates of constellation points in a constellation diagram for dividing information bits
Is less than
Is a region;
where x is the real coordinate of the input signal and y is the imaginary coordinate of the input signal.
6. A demodulating apparatus for performing the demodulating method of any one of claims 1 to 5, the demodulating apparatus comprising: the device comprises a dividing unit and a judging and calculating unit; wherein,
the dividing unit is used for: dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8QAM modulated input signal;
the judging and calculating unit is used for: for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs;
wherein, the judging and calculating unit is specifically configured to:
for the first information bit of the input signal, judging the region of the input signal according to the imaginary coordinate of the input signal, wherein an LLR calculation formula is shown as a formula (1);
for the second information bit of the input signal, judging the region of the input signal according to the real coordinate of the input signal, wherein an LLR calculation formula is shown as a formula (2);
for the third information bit of the input signal, judging the region of the input signal according to the real coordinate of the input signal, wherein an LLR calculation formula is shown as a formula (3);
the judging and calculating unit is further specifically configured to:
for the first information bit of the input signal, the LLR calculation formula is shown as formula (4);
for a second information bit of the input signal, as a function of the real part of the input signal and the imaginary part of the input signal
Judging the region to which the input signal belongs, wherein an LLR calculation formula is shown as a formula (5);
for a third information bit of the input signal as a function of the real part of the input signal and the imaginary part of the input signal
And (4) judging the region to which the input signal belongs, wherein the LLR calculation formula is shown as the formula (6).
7. A computer storage medium having stored therein computer-executable instructions for performing the demodulation method of any one of claims 1-5.
8. A terminal, the terminal comprising: a memory and a processor; wherein,
the processor is configured to execute program instructions in the memory;
program instructions to execute, on a processor, the demodulation method of any of claims 1 to 5, when read:
dividing a constellation diagram of each information bit into one or more regions according to a preset strategy for a received 8QAM modulated input signal;
for each information bit, judging the region to which the input signal belongs according to a preset strategy, and calculating LLR of the information bit according to a log-likelihood ratio LLR calculation formula corresponding to the region to which the input signal belongs;
wherein, the LLR is obtained by adopting a formula (1), a formula (2), a formula (3) or a formula (4), a formula (5) or a formula (6).
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