KR102249583B1 - Method and apparatus for generating circular layer modulation constellation - Google Patents

Abstract

Disclosed are a method and device for generating a circular layer modulation constellation. The method for generating the circular layer modulation constellation includes the steps of: (a) generating an initial constellation including the M number of signal points, wherein the initial constellation is a circular quadrature amplitude modulation signal constellation and M is a natural number; and (b) rearranging at least a plurality of signal points so that the number of signal points disposed in each quadrant in the initial constellation is the same, thereby having excellent performance in terms of the error probability of an HP bit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention Method and apparatus for generating circular layer modulation constellation

The present invention relates to a method and apparatus for generating a circular hierarchical modulation constellation.

Hierarchical modulation is a method of applying different modulation schemes in one channel, and is composed of a base layer and an enhancement layer according to the degree of protection of data. In this case, the HP (high-priority) bit containing relatively important data is allocated to the base layer with high degree of protection, and the LP (low-priority) bit containing relatively less important data is reinforced with low protection level. It is assigned to a layer, and hierarchical modulation makes it possible to selectively receive some or all of these data according to the reception environment.

Recently, as interest in digital video broadcasting (DVB) and multimedia services increases, interest in hierarchical modulation is also increasing. Hierarchical modulation is adopted and used by various standards such as DVB-T and DVB-H. In general, a quadrature phase shift keying (QPSK) is used as a base layer, that is, a square based on SQAM (Square QAM) with two HPs. Type 4/M-QAM hierarchical modulation is mainly used. In this regard, the academic world has been conducting research on hierarchical modulation performance analysis and application of hierarchical modulation in various systems.

(01) Korean Registered Patent Publication No. 10-1648569 (2016.08.09.)

An object of the present invention is to provide a method and apparatus for generating a circular hierarchical modulation constellation.

In addition, the present invention is to provide a circular hierarchical modulation constellation generation method and apparatus having excellent performance in terms of the error probability of HP bits.

In addition, the present invention is to provide a method and apparatus for generating a circular hierarchical modulation constellation that can be effectively used in recent wireless communication and broadcasting systems requiring large-capacity data transmission.

According to an aspect of the present invention, a method for generating a circular hierarchical modulation constellation is provided.

According to an embodiment of the present invention, (a) generating an initial constellation including M (M is a natural number) signal points-the initial constellation is a circular orthogonal amplitude modulated signal constellation; And (b) rearranging at least a plurality of signal points such that the number of signal points disposed in each quadrant in the initial constellation is the same.

Prior to step (b), the step of setting a candidate signal point at an adjacent empty position of each signal point in the initial constellation diagram may be further included.

In step (b), some of the signal points of some quadrants from the initial constellation map may be removed, and some of the candidate signal points of other adjacent quadrants may be set as new signal points.

The step (b) may include determining whether the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants; If the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, removing a signal point having the largest magnitude among signal points in each of the odd-numbered quadrants; And setting a candidate signal point having the smallest magnitude among candidate signal points in each of the even-numbered quadrants as a new signal point.

In the step (b), if the number of signal points in the odd-numbered quadrants is smaller than the number of signal points in the even-numbered quadrants, the signal point having the largest magnitude among the signal points in each of the even-numbered quadrants is removed. step; And setting a candidate signal point having the smallest magnitude among candidate signal points in each of the odd-numbered quadrants adjacent to the even-numbered quadrant as a new signal point.

According to another aspect of the present invention, a constellation generating apparatus for generating a circular hierarchical modulation constellation is provided.

According to an embodiment of the present invention, an initial constellation including M (M is a natural number) signal points is an initial constellation generator-the initial constellation is a circular orthogonal amplitude modulated signal constellation; And a signal point rearrangement unit for rearranging at least a plurality of signal points such that the number of signal points arranged in each quadrant in the initial constellation map is the same.

The signal point rearrangement unit may set a candidate signal point at an adjacent empty position of each signal point in the initial constellation diagram.

The signal point rearrangement unit may remove some of the signal points of some quadrants from the initial constellation and set some of the candidate signal points of the other adjacent quadrants as new signal points.

The signal point rearrangement unit determines whether the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, and if the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, each of the odd-numbered quadrants The signal point having the largest magnitude among the signal points of may be removed, and a candidate signal point having the smallest magnitude among the candidate signal points of each of the even-numbered quadrants may be set as the new signal point.

When the number of signal points in the odd-numbered quadrants is smaller than the number of signal points in the even-numbered quadrants, the signal point rearrangement unit removes the signal point having the largest magnitude among the signal points in the even-numbered quadrants, and the even-numbered quadrant A candidate signal point having the smallest magnitude among candidate signal points in each of the odd-numbered quadrants adjacent to the fourth quadrant may be set as a new signal point.

By providing a method and apparatus for generating a circular layer modulation constellation according to an embodiment of the present invention, it has excellent performance in terms of the error probability of HP bits, and thus, is effectively used in recent wireless communication and broadcasting systems that require large-capacity data transmission. Can be used.

1 is a flowchart illustrating a method of generating a circular hierarchical modulation constellation according to an embodiment of the present invention.
2 is a flow chart showing a signal point relocation method according to an embodiment of the present invention.
3 is a diagram illustrating a signal point and a candidate signal point according to an embodiment of the present invention.
4 is a block diagram schematically showing an internal configuration of an apparatus for generating a constellation diagram according to an embodiment of the present invention.
5 is a diagram illustrating a circular hierarchical modulation constellation according to an embodiment of the present invention.
6 is a diagram illustrating bit mapping according to an embodiment of the present invention.
7 to 9 are graphs comparing the performance of the present invention with a conventional bit error probability.

Singular expressions used in the present specification include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various elements or various steps described in the specification, and some of the elements or some steps It may not be included, or it should be interpreted that it may further include additional components or steps. In addition, terms such as "... unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart showing a method of generating a circular hierarchical modulation constellation according to an embodiment of the present invention, FIG. 2 is a flow chart showing a signal point relocation method according to an embodiment of the present invention, and FIG. A diagram illustrating a signal point and a candidate signal point according to an exemplary embodiment.

In step 110, the constellation generating apparatus 100 generates an initial constellation including M (M is a natural number) signal points.

-QAM)을 기반으로 초기 성상도를 생성하는 것을 가정하기로 한다. M-ary CTQAM을 기반으로 초기 성상도를 생성하는 방법 자체는 당업자에게는 자명한 사항이므로 이에 대한 별도의 설명은 생략하기로 한다. In an embodiment of the present invention, M-ary CTQAM (circular

-QAM) to create an initial constellation. The method of generating the initial constellation based on the M-ary CTQAM itself is obvious to those skilled in the art, so a separate description thereof will be omitted.

In step 115, the constellation generating apparatus 100 rearranges some of the signal points so that the number of signal points located in each quadrant in the initial constellation is the same.

Hereinafter, a process of rearranging some signal points will be described in more detail with reference to FIG. 2.

In step 210, the constellation generating apparatus 100 counts the number of even-numbered and odd-numbered signal points of the constellation.

라 정의하며, 짝수번째 사분면들에 위치한 신호점들의 개수를

라 정의하기로 한다. For convenience, the number of signal points located in the odd quadrants

Is defined as, and the number of signal points located in the even quadrants

It will be defined as.

Also, the set of signal points included in each quadrant of the initial constellation is defined as Sn.

It will be described with reference to FIG. 3.

3 illustrates signal points and candidate signal points included in an initial constellation generated based on 64-ary CTQAM.

로 표기할 수 있다. 여기서, n이 홀수일 때

이고, n이 짝수일 때

이다. In designating the index of signal points included in each quadrant, the index can be designated by increasing the number from left to right and top to bottom of each quadrant. For example, as shown in Fig. 2, the signal points in each quadrant are in the order of left to right and top to bottom.

It can be expressed as Here, when n is odd

And when n is even

to be.

In step 215, the constellation generating apparatus 100 sets candidate signal points in the initial constellation.

Candidate signal points may be set as empty spaces (positions) adjacent to signal points included in the signal constellation. As shown in FIG. 3, candidate signal points may be set on the outer periphery of signal points included in the constellation diagram as a result.

으로 표기하기로 한다. 또한, n이 홀수일 때,

이고, n이 짝수일 때

이다. 또한,

는 홀수번째 사분면들에 위치한 후보 신호점들의 개수로 정의하기로 하며,

는 짝수번째 사분면들에 위치한 후보 신호점들의 개수로 정의하기로 한다. For convenience, the indexes of the candidate signal points are also left to right and top to bottom.

It will be marked as. Also, when n is odd,

And when n is even

to be. Also,

Is defined as the number of candidate signal points located in odd-numbered quadrants,

Is defined as the number of candidate signal points located in the even-numbered quadrants.

이며, 2d는 인접한 신호점간의 유클리드 거리이다. That is, in FIG. 3, signal points of 64-ary CTQAM and candidate signal points for rearrangement of the signal points are illustrated. In Figure 3

And 2d is the Euclidean distance between adjacent signal points.

인지 여부를 판단한다. In step 220, the constellation generating device 100

Determine whether or not.

이면, 단계 225에서 성상도 생성 장치(100)는 홀수번째 사분면에서 짝수번째 사분면으로 신호점 일부가 재배치된다. if

Then, in step 225, the constellation generating apparatus 100 rearranges some of the signal points from the odd-numbered quadrant to the even-numbered quadrant.

That is, the signal point having the largest magnitude among the signal points included in the first and third quadrants is removed, and a candidate signal point having the smallest magnitude among the candidate signal points included in the second and fourth quadrants is newly added. It is additionally set as a signal point.

라 정의하기로 하며, 후보 신호점들 중 매그니튜드가 가장 작은 신호점을

이라 가정하기로 한다. For example, among the signal points in each quadrant, the signal point with the largest magnitude

Is defined as, and among the candidate signal points, the signal point with the smallest magnitude is

Let's assume it is.

이라 하고, 후보 신호점들을

로 정의하기로 한다. For example, among the signal points in each of the first and third quadrants, the signal point with the largest magnitude

And the candidate signal points

It will be defined as.

,

라 하면, 성상도 생성 장치(100)는 제1 사분면, 제3 사분면에서

,

인 신호점을 각각 제거한다. The signal point with the largest magnitude among the signal points in the first and third quadrants is selected, respectively.

,

In the first quadrant and the third quadrant, the constellation generating device 100

,

Remove each signal point.

,

라 칭하기로 한다. 성상도 생성 장치(100)는 제1 사분면, 제3 사분면에 인접한 제2 사분면, 제4 사분면의

,

를 신규 신호점으로 설정한다. The candidate signal points having the smallest magnitude among the candidate signal points set in the second and fourth quadrants are respectively

,

It will be called as. The constellation generating device 100 includes a first quadrant, a second quadrant adjacent to the third quadrant, and a fourth quadrant.

,

Is set as a new signal point.

이 제거된 후 이에 대응하여 제2 사분면 또는 제4 사분면의

,

중 어느 하나가 신규 신호점으로 재설정될 수 있다. 이와 같은 경우, 제3 사분면의

이 제거된 후 제2 사분면 또는 제4 사분면의

,

중 다른 하나가 신규 신호점으로 재설정될 수 있다. For convenience of understanding and explanation, it is assumed that the signal points in the first quadrant and the candidate signal points in the second quadrant are rearranged, and the candidate signal points in the third and fourth quadrants are rearranged. of

Of the second or fourth quadrants correspondingly after is removed.

,

Either of them can be reset to a new signal point. In this case, the third quadrant

Of the second quadrant or the fourth quadrant after is removed

,

The other can be reset to a new signal point.

이면, 단계 230에서 성상도 생성 장치(100)는 짝수번째 사분면에서 홀수번째 사분면으로 신호점이 재배치된다. But what if

Then, in step 230, the constellation generating apparatus 100 rearranges the signal points from the even-numbered quadrant to the odd-numbered quadrant.

이라 하고, 제4 사분면의 신호점들 중 매그니튜드가 가장 큰 신호점을

라 칭하기로 한다. For example, among the signal points in the second quadrant, the signal point with the largest magnitude

And the signal point with the largest magnitude among the signal points in the fourth quadrant

It will be called as.

이라 하고, 제3 사분면의 후보 신호점들 중 매그니튜드가 가장 작은 후보 신호점들을

라 칭하기로 한다. Also, among the candidate signal points in the first quadrant, the candidate signal point with the smallest magnitude is selected.

And, among the candidate signal points in the third quadrant, the candidate signal points with the smallest magnitude

It will be called as.

,

을 제거한다. 이어, 성상도 생성 장치(100)는 제1 사분면과 제3 사분면의

과

을 신규 신호점으로 설정한다. The signal constellation generating device () is the second and fourth quadrants.

,

Remove. Subsequently, the constellation map generating device 100 includes the first and third quadrants.

and

Is set as a new signal point.

The constellation generating apparatus 100 repeats the process of FIG. 2 until the number of signal points of each quadrant becomes the same.

In step 120, the constellation generating apparatus 100 generates a circular hierarchical modulated signal constellation by applying the constellation parameter to the constellation in which the signal points are rearranged.

일 수 있다. Here, the constellation parameter is

Can be

4 is a block diagram schematically showing an internal configuration of an apparatus for generating a constellation diagram according to an embodiment of the present invention, and FIG. 5 is a diagram illustrating a circular hierarchical modulation constellation according to an embodiment of the present invention. 6 is a diagram illustrating bit mapping according to an embodiment of the present invention, and FIGS. 7 to 9 are graphs comparing the performance of the present invention with a conventional bit error probability.

Referring to FIG. 4, a constellation generating apparatus 100 according to an embodiment of the present invention includes an initial constellation generating unit 410, a signal point rearranging unit 420, a memory 430, and a processor 440. It is composed of.

-QAM)을 기반으로 초기 성상도를 생성할 수 있다. The initial constellation generator 410 generates an initial constellation. Here, the initial constellation generating unit 410 is an M-ary CTQAM (circular

-QAM) can generate an initial constellation.

Since this is the same as already known, a redundant description will be omitted.

The signal point rearrangement unit 420 rearranges some of the signal points until the number of signal points in each quadrant is the same in the initial constellation diagram.

The signal point rearrangement unit 420 first sets a candidate signal point at an empty position adjacent to the signal point included in each quadrant in order to rearrange some of the signal points of some quadrants to other quadrants. The positions of the candidate signal points may be empty positions adjacent to the signal point in which the signal point is not generated based on the M-ary CTQAM, but the signal point based on the M-ary CTQAM is not generated.

When the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, the signal point rearrangement unit 420 may rearrange some signal points from the odd-numbered quadrant to the even-numbered quadrant.

For example, a signal point having the largest magnitude among signal points in the first and third quadrants is removed, and a candidate signal point having the smallest magnitude among the signal points in the second and fourth quadrants is set as a new signal point. I can.

Also, when the number of signal points in the odd-numbered quadrants is smaller than the number of signal points in the even-numbered quadrants, the signal point rearrangement unit 420 may rearrange some signal points from the even-numbered quadrant to the odd-numbered quadrant.

For example, a signal point having the largest magnitude among signal points in the second and fourth quadrants is removed, and a candidate signal point having the smallest magnitude among the signal points in the first and third quadrants is set as a new signal point. I can.

The signal point rearrangement unit 420 may repeatedly perform until the number of signal points in each quadrant becomes the same. That is, until the number of signal points in each quadrant becomes the same, the signal point rearrangement unit 420 repeats the process of relocating the signal points from some quadrants to other quadrants after setting candidate signal points adjacent to the signal points. You can do it. Since this is the same as already described above, a redundant description will be omitted.

The memory 430 stores instructions (program codes) necessary to perform the method of generating a circular hierarchical modulation constellation according to an embodiment of the present invention, data derived from this process, and the like.

The processor 440 includes internal components of the constellation generating apparatus 100 according to an embodiment of the present invention (eg, an initial constellation generating unit 410, a signal point rearranging unit 420, and a memory 430). ), etc.).

In addition, the processor 440 generates a final constellation by applying the constellation parameter to the constellation in which the signal point relocation has been completed.

=60°이고 α=2 일 때, 변조 차수 M=64, 128, 256, 512, 1024, 2048에 대한 원형의 계층 변조 신호 성상도를 도시한 도면이다. 이 때, 설계된 성상도는

에 따라 다양한 격자 구조를 갖고 QPSK를 기본 계층으로 가지며, 변조 차수가 증가할수록 전체적인 형태가 원형이 되므로 이를 4/M-circular

-QAM (4/M-CTQAM)으로 명명하기로 한다. In Figure 5

When =60° and α=2, a diagram showing a constellation of a circular hierarchical modulation signal for modulation orders M=64, 128, 256, 512, 1024, and 2048. At this time, the designed constellation

It has various lattice structures and has QPSK as the base layer, and the overall shape becomes circular as the modulation order increases, so this is 4/M-circular.

It will be named -QAM (4/M-CTQAM).

For bit mapping of 4/M-CTQAM, a known layer labeling algorithm may be used. At this time, 4/M-CTQAM having QPSK as the base layer has two HP bits, so after allocating these HP bits to the most significant bit, that is, 00, 10, After allocating 11 and 01 to the most significant bit, the remaining bits can be mapped using a layer labeling algorithm. As an example, FIG. 6 is a diagram illustrating bit mapping of 4/64-CTQAM.

이고 변조 차수 M=64, 256, 1024 일 때, 본 발명의 일 실시예에 따른 원형 계층 변조 성상도(4/M-CTQAM)와 종래의 4/M-QAM의 HP 및 LP 비트의 비트 오류 확률(BER; Bit Error Rate) 성능을 각각 나타낸 그래프이다. 도 7 내지 도 9에서 보여지는 바와 같이, M = 64, 256, 1024 일 때, HP 비트의 경우 BER = 10-5에서 4/M-CTQAM이 4/M-QAM 보다 각각 0.5 dB, 0.8 dB, 0.9 dB의 성능 이득을 갖는 것을 확인할 수 있다.7, 8 and 9, in the AWGN channel

And modulation order M=64, 256, 1024, circular hierarchical modulation constellation (4/M-CTQAM) according to an embodiment of the present invention and bit error probability of HP and LP bits of conventional 4/M-QAM This is a graph showing the performance of (BER; Bit Error Rate). 7 to 9, when M = 64, 256, 1024, in the case of the HP bit, 4/M-CTQAM is 0.5 dB, 0.8 dB, respectively, than 4/M-QAM at BER = 10-5, It can be seen that it has a performance gain of 0.9 dB.

The apparatus and method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in the computer software field. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -Includes magneto-optical media and hardware devices specially configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like.

The above-described hardware device may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

So far, the present invention has been looked at around the embodiments. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from a descriptive point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

100: constellation generating device
410: initial constellation generator
420: signal point rearrangement unit
430: memory
440: processor

Claims (11)

(a) generating an initial constellation including M (M is a natural number) signal points-the initial constellation is a circular orthogonal amplitude modulated signal constellation;
(b) setting a candidate signal point at an adjacent empty position of each signal point in the initial constellation diagram;
(c) relocating at least some of the candidate signal points so that the number of signal points arranged in each quadrant in the initial constellation is the same,
The step (c),
Determining whether the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants;
If the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, removing a signal point having the largest magnitude among signal points in each of the odd-numbered quadrants; And
And setting a candidate signal point having the smallest magnitude among candidate signal points in each of the even-numbered quadrants as a new signal point.
delete The method of claim 1,
The step (c),
A method for generating a circular hierarchical modulation constellation, comprising removing some of the signal points of some quadrants from the initial constellation and setting some of the candidate signal points of other adjacent quadrants as new signal points.
delete The method of claim 1,
The step (c),
If the number of signal points in the odd-numbered quadrants is smaller than the number of signal points in the even-numbered quadrants, removing a signal point having the largest magnitude among the signal points in each of the even-numbered quadrants; And
And setting a candidate signal point having the smallest magnitude among candidate signal points of each of the odd-numbered quadrants adjacent to the even-numbered quadrant as a new signal point.
A computer-readable recording medium on which a program code for performing the method according to claim 1 is recorded.
An initial constellation generating unit for an initial constellation including M (M is a natural number) signal points-the initial constellation is a circular orthogonal amplitude modulated signal constellation; And
A signal point for setting a candidate signal point at an empty position adjacent to each signal point in the initial constellation and rearranging some of the candidate signal points so that the number of signal points arranged in each quadrant in the initial constellation is the same Including a relocation unit,
The signal point rearrangement unit,
It is determined whether the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, and if the number of signal points in the odd-numbered quadrants is greater than the number of signal points in the even-numbered quadrants, the signal points of each of the odd-numbered quadrants A constellation diagram generation characterized in that the signal point having the largest magnitude among them is removed, and the candidate signal point having the smallest magnitude among the candidate signal points in each of the even-numbered quadrants is set as a new signal point. Device.
delete The method of claim 7,
The signal point rearrangement unit,
And removing some of the signal points of some quadrants from the initial constellation map and setting some of the candidate signal points of other adjacent quadrants as new signal points.
delete The method of claim 7,
The signal point rearrangement unit,
If the number of signal points in the odd-numbered quadrants is less than the number of signal points in the even-numbered quadrants, the signal point having the largest magnitude among the signal points in each of the even-numbered quadrants is removed, and the signal point adjacent to the even-numbered quadrant is removed. A constellation generating apparatus, characterized in that, among candidate signal points of each odd-numbered quadrant, a candidate signal point having the smallest magnitude is set as a new signal point.

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