A method, device, storage medium and program product for reducing out-of-band emission of a multicarrier signal

Abstract

This invention discloses a method, device, storage medium, and program product for reducing out-of-band leakage of multi-carrier signals. By mapping frozen bits to both ends of the frequency band and selecting the optimal bit combination, out-of-band leakage of the signal can be effectively suppressed without affecting the receiving performance. It does not require changes to the existing communication system and standards. The transmitting end only needs to add a simple sorter, and the receiving end needs to perform desorting processing.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to a method, apparatus, storage medium, and program product for reducing out-of-band leakage of multi-carrier signals. Background Technology

[0002] Currently, standardization work on the sixth-generation mobile communication system (6G) has begun, with large-scale commercial use expected by 2030. Unlike the fifth-generation mobile communication system (5G), 6G will support six typical scenarios: immersive communication, ultra-large-scale connectivity, ultra-reliable low-latency communication, convergence of artificial intelligence and communication, convergence of sensing and communication, and ubiquitous connectivity. From the current standardization process, 6G still uses multi-carrier modulation technology based on orthogonal frequency division multiplexing (OFDM) for the air interface, and uses polar codes and low-density parity-check codes (LDPC) as channel coding schemes.

[0003] Traditional OFDM baseband signals use rectangular time-domain window functions, resulting in high sidelobes on frequency-domain subcarriers. The superposition of sidelobes from multiple subcarriers causes severe out-of-band (OOB) leakage, interfering with adjacent frequency bands. While time-domain windowing can reduce sidelobes, this reduces subcarrier orthogonality, introducing inter-carrier interference (ICI). Therefore, 5G NR uses a guard band, comprising approximately 5-10% of the total bandwidth, on both sides of the signal, without modulating any signal to reduce OOB leakage. However, since the guard band carries no useful information, it reduces the system's spectral efficiency. Future 6G technologies will employ larger bandwidths and more subcarriers, placing even greater demands on reducing OOB leakage and improving spectral efficiency. Summary of the Invention

[0004] Purpose of the invention: This invention provides a method, device, storage medium, and program product for reducing out-of-band leakage of multi-carrier signals. By mapping polar code frozen bits to both ends of the frequency band and selecting the optimal combination, out-of-band leakage of the signal can be effectively reduced without affecting the receiving performance.

[0005] Technical solution: The method for reducing out-of-band leakage of multi-carrier signals according to the present invention includes the following steps:

[0006] Step 1: The system is given a coding rate R and a modulation order q, and is configured to transmit an information bit sequence of length N on L subcarriers. ;

[0007] Step 2, the sending end according to The encoded block length is calculated to be M. Given MN different combinations of frozen bits, there are a total of... There are several combinations, and p is set as the index of each combination, with an initial value of 1;

[0008] Step 3: The sending end selects the p-th combination of frozen bits and combines it with... The input is a polar code encoder, and the output is a sequence of encoded information bits of length M. ;

[0009] Step 4, The sorter sorts the split channels in descending order of quality. Rearranging the elements in the result ;

[0010] Step 5: Follow the system requirements Modulate adjacent elements in the matrix to obtain ,in ;

[0011] Step 6, The first K elements are mapped to the subcarriers in the middle of the transmitted signal. The last LK elements are mapped sequentially to the subcarriers on both sides. Above, among which ;

[0012] Step 7: Calculate the total power of the sidelobes The results are then combined with the corresponding frozen bits and stored. For coefficients;

[0013] Step 8: Set p = p + 1, then jump to step 3;

[0014] Step 9: Select the smallest The result of the value is sent.

[0015] Furthermore, in step 1, the information bit sequence N is the length.

[0016] Furthermore, in step 4, the p-th encoded and sorted bit sequences are respectively and M is the length of the encoded block, and p is the sequence number of each combination.

[0017] Furthermore, in step 5, the modulation symbol sequence And assume that q is divisible by M and N.

[0018] Furthermore, in step 6, the intermediate subcarrier numbers are respectively The 0th subcarrier does not carry any data; the subcarrier numbers on both sides are respectively... K represents the first K elements.

[0019] Furthermore, in step 7, assuming the guard bands on both sides of the signal are B, the subcarrier indices outside the band are respectively... The coefficient is calculated by the following formula:

[0020]

[0021] in, This represents the frequency of the i-th subcarrier; Indicates the bandwidth of the subcarrier; express The subcarrier mapped by the l-th element in the middle, This indicates the modulo operation.

[0022] Furthermore, in step 9, since the polar code has MN frozen bits, it will generate After calculating several different combinations, we get... indivual The system selects the minimum value from these values. Value As a transmitted signal, that is:

[0023]

[0024] in, This indicates the sequence number of the frozen bit combination that can produce the minimum value.

[0025] Accordingly, a device for reducing out-of-band leakage of multi-carrier signals includes: one or more processors;

[0026] Storage device for storing one or more programs or user data;

[0027] When the one or more programs are executed by one or more processors, the one or more processors implement a method for reducing out-of-band leakage of multicarrier signals.

[0028] Accordingly, a storage medium for reducing out-of-band leakage of multi-carrier signals is provided, wherein a computer program is stored thereon, which, when executed by a processor, implements a method for reducing out-of-band leakage of multi-carrier signals.

[0029] Accordingly, a program product for reducing out-of-band leakage of multi-carrier signals includes a computer program that, when executed by a processor, implements a method for reducing out-of-band leakage of multi-carrier signals.

[0030] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: by mapping the frozen bits to both ends of the frequency band and selecting the optimal bit combination, the out-of-band leakage of the signal can be effectively suppressed without reserving a protective subcarrier; the present invention only performs data exchange in the frequency domain, which will not lead to a decrease in the orthogonality between subcarriers; in addition, the present invention does not require changes to the existing communication system and standards, the transmitting end only needs to add a simple sorter, and the receiving end needs to perform desorting processing. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0032] Figure 2 This is a diagram of the polar code encoding structure with a code length of 8 in this invention.

[0033] Figure 3 This is a schematic diagram of subcarrier mapping in this invention. Detailed Implementation

[0034] like Figure 1 As shown, a method for reducing out-of-band leakage of multi-carrier signals includes the following steps:

[0035] Step 1: The system is given a coding rate R and a modulation order q, and is configured to transmit an information bit sequence of length N on L subcarriers. ;

[0036] Step 2, the sending end according to The encoded block length is calculated to be M. Given MN different combinations of frozen bits, there are a total of... There are several combinations, and p is set as the index of each combination, with an initial value of 1;

[0037] Step 3: The sending end selects the p-th combination of frozen bits and combines it with... The input is a polar code encoder, and the output is a sequence of encoded information bits of length M. ;

[0038] Step 4, The sorter sorts the split channels in descending order of quality. Rearranging the elements in the result ;

[0039] Step 5: Follow the system requirements Modulate adjacent elements in the matrix to obtain ,in ;

[0040] Step 6, The first K elements are mapped to the subcarriers in the middle of the transmitted signal. The last LK elements are mapped sequentially to the subcarriers on both sides. Above, among which ;

[0041] Step 7, Calculation The results are then combined with the corresponding frozen bits and stored. For coefficients;

[0042] Step 8: Set p = p + 1, then jump to step 3;

[0043] Step 9: Select the smallest The result of the value is sent.

[0044] Among them, the information bit sequence The p-th encoded and sorted bit sequences are respectively and Modulation symbol sequence And assume that q is divisible by M and N. The intermediate subcarrier indices are respectively Subcarrier number 0 carries no data. The subcarrier numbers on both sides are... Assuming the guard bands on both sides of the signal are B, then the out-of-band subcarrier indices are respectively... The coefficients in step 7 are calculated using the following formula:

[0045]

[0046] in, This represents the frequency of the i-th subcarrier; Indicates the bandwidth of the subcarrier; express The subcarrier mapped by the l-th element. Additionally, This indicates the modulo operation.

[0047] Consider an OFDM system that uses polar codes as the channel encoder to transmit a binary information bit sequence of length N. Assuming that MN bits are frozen bits, the encoded code rate is... The system first sets the value of the freeze bit and sends it along with the information bits to the polar code encoder, outputting a binary encoded sequence of length M. ,in Assuming MN is 3, then There are 8 possible combinations, and the values ​​of the 3 frozen bits are shown in the table below:

[0048] Table 1 Different combinations of three frozen bits 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1

[0049] The system needs to iterate through all 8 possible frozen bits to obtain 8 possible results. .

[0050] During channel polarization, the encoder can calculate the reliability of each polarization channel using methods such as the Bhattacharyya parameter or density evolution, and then rank the channels according to their reliability from highest to lowest. Higher reliability equates to a better channel, and vice versa. The encoder then transmits data on the N best channels based on the coding rate R. Furthermore, frozen bits are placed on the worst-case MN channels. Unlike traditional OFDM systems, the proposed scheme requires the encoded bit sequence to be... Input sorter, such as Figure 1 As shown. The sorter sorts the channels according to their quality. Rearranging the elements in the result For example, consider a polar code with M=8, whose encoding structure is as follows: Figure 2 As shown. Among them, Let represent the channel after the i-th polarization. Assuming the Parseltongue parameter method is used, by calculating the reliability of each channel, the encoder obtains the polarization channels in descending order of reliability as follows: If R=1 / 2, the encoder operates on the best N=4 channels, i.e. , , and Send separately , , and Freeze bits are placed on the remaining 4 bad channels to obtain Next, the sorter re-sorts the channels according to their quality. The elements in the sorted array are obtained as follows:

[0051] (1)

[0053] In the modulation stage, the system modulates the signal according to the given modulation order q. The adjacent elements in the matrix are modulated using a constellation diagram, where q is divisible by both M and N. In the example above, assuming q=1, the BPSK modulation can be obtained as follows:

[0054] (2)

[0056] If QPSK modulation with q=2 is used, the example above would be:

[0057] (3)

[0058] Where j represents the imaginary unit.

[0059] Unlike traditional subcarrier mapping, the proposed scheme requires... The first K elements are mapped to the middle subcarrier of the transmitted signal frequency band, that is, mapped to the subcarrier with sequence number . On the subcarrier, among which Since subcarrier number 0 is a DC component, it typically does not carry any data. The last LK elements are mapped sequentially to the subcarriers on both sides of the signal bandwidth, that is, mapped to the subcarriers with sequence numbers... On the subcarriers. To prevent sidelobes from interfering with the frequencies of adjacent systems, guard bands (B) are typically provided on both sides of the signal bandwidth. In this case, the subcarrier numbers within the guard band are: Taking q=1 as an example, the first K=4 elements represent good channels, placed at sequence number... On the subcarrier, the last four elements are placed sequentially on both sides with the following sequence numbers. On the subcarrier. Assuming the guard bands on both sides of the signal consist of 2 subcarriers, i.e., B=2, then the out-of-band subcarrier numbers are... ,like Figure 3 As shown.

[0060] To reduce interference to adjacent systems, the total power within the sidelobes needs to be reduced. Since different combinations of frozen bits will output different coded bits without affecting performance, the combination of frozen bits with the lowest total sidelobe power can be selected to generate the signal for transmission, thereby effectively reducing interference to adjacent channels. Because OFDM signals typically use a rectangular window in the time domain, the total power within the sidelobes after the p-th change of the frozen bits can be calculated using the following formula:

[0061] (4)

[0062] in, This represents the modulo operation. The coefficients in formula (4) are:

[0063] (5)

[0064] in, This represents the frequency of the i-th subcarrier; Indicates the bandwidth of the subcarrier; express The subcarrier mapped by the l-th element in the code. Since the polar code has MN frozen bits, it will produce... After calculating several different combinations, we get... indivual The system selects the minimum value from these. Value As a transmitted signal, that is:

[0065] (6)

[0066] in, This indicates the sequence number of the frozen bit combination that can produce the minimum value.

[0067] This invention proposes a method for reducing out-of-band leakage of polar-coded multicarrier signals. By mapping the polar code frozen bits to both ends of the frequency band and selecting the optimal combination, the out-of-band leakage of the signal can be effectively reduced without affecting the receiving performance. It does not conflict with existing systems, does not require additional components, and is simple to implement.

Claims

1. A method for reducing out-of-band leakage of multi-carrier signals, characterized in that, Includes the following steps: Step 1: The system is given a coding rate R and a modulation order q, and is configured to transmit an information bit sequence of length N on L subcarriers. ; Step 2, the sending end according to The encoded block length is calculated to be M. Given MN different combinations of frozen bits, there are a total of... There are several combinations, and p is set as the index of each combination, with an initial value of 1; Step 3: The sending end selects the p-th combination of frozen bits and combines it with... The input is a polar code encoder, and the output is a sequence of encoded information bits of length M. ; Step 4, The sorter sorts the split channels in descending order of quality. Rearranging the elements in the result ; Step 5: Follow the system requirements Modulate adjacent elements in the matrix to obtain ,in ; Step 6, The first K elements are mapped to the subcarriers in the middle of the transmitted signal. The last LK elements are mapped sequentially to the subcarriers on both sides. Above, among which ; Step 7: Calculate the total power of the sidelobes The results are then combined with the corresponding frozen bits and stored. For coefficients; Step 8: Set p = p + 1, then jump to step 3; Step 9: Select the smallest The result of the value is sent.

2. The method for reducing out-of-band leakage of multi-carrier signals as described in claim 1, characterized in that, In step 1, the information bit sequence N is the length.

3. The method for reducing out-of-band leakage of multi-carrier signals as described in claim 1, characterized in that, In step 4, the p-th encoded and sorted bit sequences are respectively and M is the length of the encoded block, and p is the sequence number of each combination.

4. The method for reducing out-of-band leakage of multi-carrier signals as described in claim 1, characterized in that, In step 5, the modulation symbol sequence And assume that q is divisible by M and N.

5. The method for reducing out-of-band leakage of multi-carrier signals as described in claim 1, characterized in that, In step 6, the intermediate subcarrier numbers are respectively The 0th subcarrier does not carry any data; the subcarrier numbers on both sides are respectively... K represents the first K elements.

6. The method for reducing out-of-band leakage of multi-carrier signals as described in claim 1, characterized in that, In step 7, assuming the guard bands on both sides of the signal are B, the subcarrier indices outside the band are respectively The coefficient is calculated by the following formula: in, This represents the frequency of the i-th subcarrier; Indicates the bandwidth of the subcarrier; express The subcarrier mapped by the l-th element in the middle, This indicates the modulo operation.

7. The method for reducing out-of-band leakage of multi-carrier signals as described in claim 1, characterized in that, In step 9, since the polar code has MN frozen bits, it will generate After calculating several different combinations, we get... indivual The system selects the minimum value from these values. Value As a transmitted signal, that is: in, This indicates the sequence number of the frozen bit combination that can produce the minimum value.

8. A device for reducing out-of-band leakage of multi-carrier signals, comprising: One or more processors; Storage device for storing one or more programs or user data; When the one or more programs are executed by one or more processors, the one or more processors implement the method for reducing out-of-band leakage of multicarrier signals as described in any one of claims 1 to 7.

9. A storage medium for reducing out-of-band leakage of multicarrier signals, wherein a computer program is stored thereon, which, when executed by a processor, implements the method for reducing out-of-band leakage of multicarrier signals as described in any one of claims 1 to 7.

10. A program product for reducing out-of-band leakage of multicarrier signals, comprising a computer program that, when executed by a processor, implements the method for reducing out-of-band leakage of multicarrier signals as described in any one of claims 1 to 7.

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