Method and system for accelerating communication network

Abstract

The invention discloses an acceleration method and system for a communication network, and the method comprises the steps: distributing small signals, which need higher receiving power, of a recovered signal to a plurality of optical network units of which the power margin sequence is closest to the top, and distributing large signals, which need relatively lower receiving power, of the recovered signal to the remaining optical network units. The power margin of all optical network units is fully utilized, and the overall transmission rate of a communication network is improved. Moreover, the large signal and the small signal are superposed and coded to generate the NOMA signal, the NOMA signal is transmitted to the optical network unit side through the optical fiber channel, and the time domain feature of the small signal is disordered through scrambling operation on the optical line terminal side, so that the feature of the small signal in the time domain is similar to that of Gaussian white noise. The NOMA signal obtained by superposition coding with the large signal can meet the eye pattern template of the original speed signal, namely the large signal; therefore, according to a signal distribution result, a small signal and a large signal are respectively recovered from the NOMA signal of the receiving end by using the corresponding optical network unit.

Description

Technical Field

[0001] The present invention relates to a transmission technology of an optical communication network, and in particular to a speed-increasing method and system for a communication network. Background Art

[0002] With the rapid development of information technology, users are increasingly demanding bandwidth for optical access. With the completion of standardization, 50G passive optical networks (PONs), a key solution for next-generation optical access, have become a hot topic of research. Differentiating PON rates is a key approach to enhancing product competitiveness. Because the fiber lengths and number of optical splitters between the central office and different optical network units (ONUs) vary, the attenuation of different links also varies. While each ONU typically operates at the same rate, the corresponding optical power budget is greater than or equal to the maximum link attenuation. However, the power margin of most ONUs is underutilized.

[0003] In addition to increasing the sampling rate, existing speed-up technologies generally achieve rate increases by power-division multiplexing the original-speed signal or increasing the wavelength to couple in the optical domain to obtain a NOMA signal. However, these solutions either fail to meet the eye diagram template of the original-speed signal or the performance cost of the original-speed signal and the speed-up signal is too high. Summary of the Invention

[0004] One of the technical problems to be solved by the present invention is to provide a method for increasing the speed of a communication network to solve the problem in the prior art that it is difficult to meet the original speed signal eye diagram template at a low performance cost while increasing the speed.

[0005] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] like Figure 1 and Figure 2 As shown, a method for increasing the speed of a communication network is characterized by comprising:

[0007] Step S1: On the optical network unit side, measure the power budget of the original speed signal and the link attenuation between each optical network unit (ONU) and the optical line terminal (OLT) on the optical network unit side to calculate the power margin of each optical network unit;

[0008] Step S2: At the optical line terminal side, according to the power margin of each optical network unit, an original speed signal and a speed-up signal to be transmitted to the optical network unit side are allocated, and the original speed signal with larger power is recorded as a large signal, and the speed-up signal with smaller power is recorded as a small signal. Specifically, the steps include:

[0009] Step S2-1, obtaining the power margin of each optical network unit calculated in step S1, and sorting the optical network units from large to small according to the power margin;

[0010] Step S2-2: first distribute the small signal to several optical network units with the highest power margin ranking, and then distribute the large signal to the remaining optical network units, so that all optical network units evenly distribute the small signal and the large signal; for example: assuming that the data volume of the small signal and the large signal are 6G and 50G respectively, and there are 56 optical network units on the optical network unit side, then each optical network unit should evenly distribute the signal with a data volume of 1G, that is: each optical network unit is sorted from large to small according to the power margin and numbered 1 to 56, then in step S2-2, the small signal should first be divided into 6 parts and then distributed to optical network units No. 1 to 6 in sequence, and then the large signal should be divided into 50 parts and then distributed to optical network units No. 7 to 56 in sequence.

[0011] Step S3: On the optical line terminal side, based on the power ratio and clipping ratio of the small signal, a NOMA signal (i.e., non-orthogonal multiple access signal) is generated by superimposing and encoding the large signal and the scrambled small signal, and the NOMA signal is converted into a transmitting end optical signal after shaping and filtering to be transmitted to the optical network unit side via the optical fiber.

[0012] Step S4: On the optical network unit side, the transmitting end optical signal is restored to a NOMA signal, which is recorded as the receiving end NOMA signal;

[0013] Step S5: According to the signal allocation result of step S2, the optical network unit allocated to the large signal recovers the large signal from the receiving end NOMA signal through continuous interference cancellation of hard decision;

[0014] Among them, since the power of the large signal is greater than that of the small signal, the small signal is regarded as interference noise when the NOMA signal is directly hard-determined at the receiving end, and the hard decision is the large signal.

[0015] Moreover, step S5 can be stopped after recovering the large signal. On the one hand, this is because the small signal is not the signal required by the optical network unit allocated to the large signal, and the small signal can be discarded; on the other hand, stopping to recover the small signal from the NOMA signal at the receiving end can avoid wasting DSP resources.

[0016] Step S6: According to the signal allocation result of step S2, the optical network unit allocated to the small signal recovers the small signal from the receiving end NOMA signal.

[0017] Therefore, the present invention prioritizes allocating small signals that require greater received power to restore the signal to the optical network units with the highest power margin, and then allocates large signals that require relatively smaller received power to restore the signal to the remaining optical network units, so as to fully utilize the power margin of all optical network units and improve the overall transmission rate of the communication network.

[0018] In addition, the present invention superimposes and encodes the large signal and the small signal to generate a NOMA signal and transmits it to the optical network unit side via the optical fiber channel. Since the time domain characteristics of the small signal are disrupted by the scrambling operation on the optical line terminal side, the characteristics of the small signal in the time domain are similar to Gaussian white noise, and thus the NOMA signal obtained by superimposing and encoding it with the large signal can meet the eye diagram template of the original speed signal, that is, the large signal; thus, according to the signal allocation result, the small signal and the large signal are respectively recovered from the NOMA signal at the receiving end using the corresponding optical network unit;

[0019] In summary, the present invention can improve the overall transmission rate of the communication network while meeting the eye diagram template of the original rate signal at a lower performance cost.

[0020] Preferably, the step S3 specifically includes:

[0021] Step S3-1: First, the bit sequence of the large signal and the bit sequence of the small signal are respectively subjected to LDPC encoding and then bit-to-symbol mapping to obtain a large signal symbol and a small signal symbol;

[0022] Secondly, the small signal symbol is repeated several times so that the data length of the repeated small signal symbol is consistent with that of the large signal symbol. For example, assuming that the small signal symbol is [1 -1 1 1], its data length is 4, and the data length of the large signal symbol is 12, the small signal symbol needs to be repeatedly encoded three times, and the repeated small signal symbol is [11 1 -1-1 -1 1 1 1 1 1 1].

[0023] Secondly, the repeated small signal symbols are scrambled to disrupt their time domain characteristics;

[0024] Secondly, the scrambled small signal symbol is amplitude-adjusted so that the power ratio between the large signal symbol and the amplitude-adjusted small signal symbol is equal to the power ratio between the large signal and the small signal;

[0025] Secondly, the NOMA signal is obtained by superimposing the small signal symbol after adjusting the amplitude and the large signal symbol;

[0026] Finally, the NOMA signal is filtered and output as a digital signal at the transmitting end;

[0027] Step S3-2: resample, digital-to-analog convert, and electro-optical modulate the transmitting end digital signal in sequence to convert it into the transmitting end optical signal.

[0028] Preferably, in step S3-1, the method for scrambling the repeated small signal symbols is as follows: according to the modulation format of the small signal, a group of random π / 2 phases or a group of random ±1 sequences are selected to multiply the small signal symbols to achieve scrambling of the small signal symbols, thereby disrupting the time domain characteristics of the small signal, so that the characteristics of the small signal in the time domain are similar to Gaussian white noise.

[0029] Wherein, the step S4 specifically includes:

[0030] Step S4-1, performing photoelectric detection, analog-to-digital conversion, and resampling on the transmitting end optical signal in sequence to obtain a receiving end digital signal;

[0031] Step S4-2: performing channel equalization on the receiving end digital signal after matched filtering to recover the receiving end NOMA signal.

[0032] Preferably, the step S6 recovers the small signal by any one of the following two methods:

[0033] Method 1: The optical network unit assigned to the small signal first performs a hard decision on the receiving end NOMA signal, then performs bit-symbol mapping to obtain a reconstructed large signal, and finally subtracts the receiving end NOMA signal from the reconstructed large signal to recover the small signal;

[0034] Method 2: The optical network unit assigned to the small signal first makes a soft decision on the receiving end NOMA signal, then performs LDPC iterative decoding (LDPC stands for low-density parity check), and then obtains the corrected large signal through bit-symbol mapping. Finally, the receiving end NOMA signal is subtracted from the corrected large signal to recover the small signal. Therefore, due to the continuous interference cancellation assisted by LDPC, a more accurate corrected large signal can be reconstructed to reduce the noise generated by large signal decision errors, thereby improving the performance of the recovered small signal and reducing the performance cost of the small signal.

[0035] The second technical problem to be solved by the present invention is to provide a speed-up system for a communication network to solve the problem in the prior art that it is difficult to meet the original speed signal eye diagram template at a low performance cost while improving the speed.

[0036] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0037] like Figure 3As shown, a communication network speed-up system is characterized by comprising: a speed-up sending system and a speed-up receiving system;

[0038] The speed-up sending system includes:

[0039] A speed-up signal generating unit is configured to generate a NOMA signal from the original speed signal and the speed-up signal, which can pass through the eye diagram template of the original speed signal, and the NOMA signal is output to the transmitter through shaping filtering to become a digital signal;

[0040] A digital-to-analog converter, configured to convert the digital signal from the transmitting end into an analog signal through digital-to-analog conversion;

[0041] an electro-optical modulator, configured to electro-optically modulate the analog signal and convert it into a transmitting optical signal so as to be transmitted to the optical network unit side via an optical fiber;

[0042] Wherein, the speed-up signal generating unit includes:

[0043] The optical network unit power margin calculation subunit is used to measure the power budget of the original speed signal and the link attenuation between each optical network unit (ONU) and the optical line terminal (OLT) on the optical network unit side to calculate the power margin of each optical network unit;

[0044] The optical network unit allocation subunit is used to allocate an original speed signal and a speed-up signal that need to be transmitted to the optical network unit side according to the power margin of each optical network unit on the optical line terminal side, and record the original speed signal with larger power as a large signal and the speed-up signal with smaller power as a small signal; wherein the specific method of signal allocation is as follows: first, obtain the power margin of each optical network unit calculated in step S1, and sort the optical network units from large to small according to the power margin; then, first allocate the small signal to several optical network units with the highest power margin, and then allocate the large signal to the optical network units. The numbers are distributed to the remaining optical network units so that all optical network units evenly distribute the small signal and the large signal; for example: assuming that the data volume of the small signal and the large signal are 6G and 50G respectively, and there are 56 optical network units on the optical network unit side, each optical network unit should evenly distribute the signal with a data volume of 1G, that is: the optical network units are sorted from large to small according to the power margin and numbered 1 to 56, then in step S2-2, the small signal should first be evenly divided into 6 parts and then distributed to optical network units No. 1 to 6 in sequence, and then the large signal should be evenly divided into 50 parts and then distributed to optical network units No. 7 to 56 in sequence.

[0045] A NOMA signal generation subunit is configured to generate, on the optical line terminal side, a NOMA signal (i.e., a non-orthogonal multiple access signal) obtained by superimposing and encoding the large signal and the scrambled small signal based on the power ratio and clipping ratio of the small signal;

[0046] The speed-up receiving system comprises:

[0047] The photoelectric detector is used to perform photoelectric detection on the optical network unit side on the sending end optical signal transmitted from the optical line terminal side through the optical fiber to obtain the receiving end analog electrical signal;

[0048] An analog-to-digital converter, configured to convert the analog electrical signal of the receiving end into a digital signal of the receiving end;

[0049] A speed-up signal recovery unit, configured to recover a large signal and a small signal from the receiving end digital signal;

[0050] Wherein, the speed-up signal recovery unit includes:

[0051] A NOMA signal recovery subunit, configured to sequentially perform matched filtering and channel equalization on the receiving end digital signal to recover a receiving end NOMA signal;

[0052] The large signal recovery subunit is configured to recover the large signal from the receiving-end NOMA signal by performing continuous interference elimination through hard decision according to the signal allocation result of the optical network unit allocation subunit. Since the power of the large signal is greater than that of the small signal, the small signal is treated as interference noise when the receiving-end NOMA signal is directly hard-determined, and the hard decision is the large signal. Furthermore, step S5 can be stopped after recovering the large signal. On the one hand, this is because the small signal is not the signal required by the optical network unit allocated to the large signal and can be discarded. On the other hand, stopping the recovery of the small signal from the receiving-end NOMA signal can avoid wasting DSP resources.

[0053] The small signal recovery subunit is used to recover the small signal from the receiving end NOMA signal of the optical network unit allocated to the small signal according to the signal allocation result of the optical network unit allocation subunit.

[0054] Therefore, the present invention prioritizes allocating small signals that require greater received power to restore the signal to the optical network units with the highest power margin, and then allocates large signals that require relatively smaller received power to restore the signal to the remaining optical network units, so as to fully utilize the power margin of all optical network units and improve the overall transmission rate of the communication network.

[0055] In addition, the present invention superimposes and encodes the large signal and the small signal to generate a NOMA signal and transmits it to the optical network unit side via the optical fiber channel. Since the time domain characteristics of the small signal are disrupted by the scrambling operation on the optical line terminal side, the characteristics of the small signal in the time domain are similar to Gaussian white noise, and thus the NOMA signal obtained by superimposing and encoding it with the large signal can meet the eye diagram template of the original speed signal, that is, the large signal; thus, according to the signal allocation result, the small signal and the large signal are respectively recovered from the NOMA signal at the receiving end using the corresponding optical network unit;

[0056] In summary, the present invention can improve the overall transmission rate of the communication network while meeting the eye diagram template of the original rate signal at a lower performance cost.

[0057] Preferably, the NOMA signal generating subunit generates the NOMA signal in the following manner:

[0058] First, the bit sequence of the large signal and the bit sequence of the small signal are respectively subjected to LDPC encoding and then bit-to-symbol mapping to obtain large signal symbols and small signal symbols;

[0059] Secondly, the small signal symbol is repeated several times so that the data length of the repeated small signal symbol is consistent with that of the large signal symbol. For example, assuming that the small signal symbol is [1 -1 1 1], its data length is 4, and the data length of the large signal symbol is 12, the small signal symbol needs to be repeatedly encoded three times, and the repeated small signal symbol is [11 1 -1-1 -1 1 1 1 1 1 1].

[0060] Secondly, the repeated small signal symbols are scrambled to disrupt their time domain characteristics;

[0061] Secondly, the scrambled small signal symbol is amplitude-adjusted so that the power ratio between the large signal symbol and the amplitude-adjusted small signal symbol is equal to the power ratio between the large signal and the small signal;

[0062] Finally, the NOMA signal is obtained by superimposing and encoding the small signal symbol after adjusting the amplitude and the large signal symbol.

[0063] Preferably, the method for scrambling the repeated small signal symbols is as follows: according to the modulation format of the small signal, a group of random π / 2 phases or a group of random ±1 sequences are selected to multiply the small signal symbols to achieve scrambling of the small signal symbols, thereby disrupting the time domain characteristics of the small signal, so that the characteristics of the small signal in the time domain are similar to Gaussian white noise.

[0064] Preferably, the small signal recovery subunit recovers the small signal by any one of the following two methods:

[0065] Method 1: The optical network unit assigned to the small signal first performs a hard decision on the receiving end NOMA signal, then performs bit-symbol mapping to obtain a reconstructed large signal, and finally subtracts the receiving end NOMA signal from the reconstructed large signal to recover the small signal;

[0066] Method 2: The optical network unit assigned to the small signal first makes a soft decision on the receiving end NOMA signal, then performs LDPC iterative decoding (LDPC stands for low-density parity check), and then obtains the corrected large signal through bit-symbol mapping. Finally, the receiving end NOMA signal is subtracted from the corrected large signal to recover the small signal. Therefore, due to the continuous interference cancellation assisted by LDPC, a more accurate corrected large signal can be reconstructed to reduce the noise generated by large signal decision errors, thereby improving the performance of the recovered small signal and reducing the performance cost of the small signal.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] First, the present invention prioritizes allocating small signals that require greater received power to restore the signal to the optical network units with the highest power margin, and then allocates large signals that require relatively less received power to the remaining optical network units, so as to fully utilize the power margin of all optical network units and improve the overall transmission rate of the communication network.

[0069] In addition, the present invention superimposes and encodes the large signal and the small signal to generate a NOMA signal and transmits it to the optical network unit side via the optical fiber channel. Since the time domain characteristics of the small signal are disrupted by the scrambling operation on the optical line terminal side, the characteristics of the small signal in the time domain are similar to Gaussian white noise, and thus the NOMA signal obtained by superimposing and encoding it with the large signal can meet the eye diagram template of the original speed signal, that is, the large signal; thus, according to the signal allocation result, the small signal and the large signal are respectively recovered from the NOMA signal at the receiving end using the corresponding optical network unit;

[0070] In summary, the present invention can improve the overall transmission rate of the communication network while meeting the eye diagram template of the original rate signal at a lower performance cost.

[0071] Second, step S6 of the present invention recovers the small signal through method 2. Since continuous interference elimination is performed with the assistance of LDPC, a more accurate large signal after correction can be reconstructed to reduce the noise generated by large signal judgment errors, thereby improving the performance of the recovered small signal and reducing the performance cost of the small signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0073] Figure 1 Schematic diagram of the speed-up method of the present invention;

[0074] Figure 2 is a flow chart of the speed-up method of the present invention;

[0075] Figure 3 It is a structural schematic diagram of the speed-up system of the present invention;

[0076] Figure 4 The probability density function diagram of the NOMA signal described in step S3-1 of the present invention;

[0077] Figure 5 The eye diagram of the NOMA signal in step S3-1 of the present invention;

[0078] Figure 6 This is a graph showing the power ratio between the large signal and the small signal obtained using hard-decision continuous interference cancellation and LDPC-assisted continuous interference cancellation, respectively, and the original rate signal, versus the received optical power difference, when a discrete multi-tone (DMT) signal is used as the small signal and the number of repetitions n=8, at a clipping ratio of -3dB.

[0079] Figure 7 This is a diagram showing the power ratio between the large signal and the small signal obtained by using hard-decision continuous interference cancellation and LDPC-assisted continuous interference cancellation and the original rate signal, respectively, when an on-off keying (OOK) signal is used as the small signal and the number of repetitions n=8 in the present invention - the received optical power difference. DETAILED DESCRIPTION

[0080] The present invention is described in detail below in conjunction with the embodiments and the accompanying drawings to help those skilled in the art better understand the inventive concept of the present invention. However, the scope of protection of the claims of the present invention is not limited to the following embodiments. For those skilled in the art, all other embodiments obtained without creative work without departing from the inventive concept of the present invention shall fall within the scope of protection of the present invention.

[0081] Example 1

[0082] like Figure 1 and Figure 2 As shown, the present invention discloses a method for increasing the speed of a communication network, comprising:

[0083] Step S1: On the optical network unit side, measure the power budget of the original speed signal and the link attenuation between each optical network unit (ONU) and the optical line terminal (OLT) on the optical network unit side to calculate the power margin of each optical network unit;

[0084] Step S2: At the optical line terminal side, according to the power margin of each optical network unit, an original speed signal and a speed-up signal to be transmitted to the optical network unit side are allocated, and the original speed signal with larger power is recorded as a large signal, and the speed-up signal with smaller power is recorded as a small signal. Specifically, the steps include:

[0085] Step S2-1, obtaining the power margin of each optical network unit calculated in step S1, and sorting the optical network units from large to small according to the power margin;

[0086] Step S2-2: first distribute the small signal to several optical network units with the highest power margin ranking, and then distribute the large signal to the remaining optical network units, so that all optical network units evenly distribute the small signal and the large signal; for example: assuming that the data volume of the small signal and the large signal are 6G and 50G respectively, and there are 56 optical network units on the optical network unit side, then each optical network unit should evenly distribute the signal with a data volume of 1G, that is: each optical network unit is sorted from large to small according to the power margin and numbered 1 to 56, then in step S2-2, the small signal should first be divided into 6 parts and then distributed to optical network units No. 1 to 6 in sequence, and then the large signal should be divided into 50 parts and then distributed to optical network units No. 7 to 56 in sequence.

[0087] Step S3: On the optical line terminal side, based on the power ratio and clipping ratio of the small signal, a NOMA signal (i.e., non-orthogonal multiple access signal) is generated by superimposing and encoding the large signal and the scrambled small signal, and the NOMA signal is converted into a transmitting end optical signal after shaping and filtering to be transmitted to the optical network unit side via the optical fiber.

[0088] Preferably, the step S3 specifically includes:

[0089] Step S3-1: First, the bit sequence of the large signal and the bit sequence of the small signal are respectively subjected to LDPC encoding and then bit-to-symbol mapping to obtain a large signal symbol and a small signal symbol;

[0090] Secondly, the small signal symbol is repeated several times so that the data length of the repeated small signal symbol is consistent with that of the large signal symbol. For example, assuming that the small signal symbol is [1 -1 1 1], its data length is 4, and the data length of the large signal symbol is 12, the small signal symbol needs to be repeatedly encoded three times, and the repeated small signal symbol is [11 1 -1-1 -1 1 1 1 1 1 1].

[0091] Secondly, the repeated small signal symbols are scrambled to disrupt their time domain characteristics;

[0092] Preferably, the method for scrambling the repeated small signal symbols is as follows: according to the modulation format of the small signal, a group of random π / 2 phases or a group of random ±1 sequences are selected to multiply the small signal symbols to achieve scrambling of the small signal symbols, thereby disrupting the time domain characteristics of the small signal, so that the characteristics of the small signal in the time domain are similar to Gaussian white noise.

[0093] Secondly, the scrambled small signal symbol is amplitude-adjusted so that the power ratio between the large signal symbol and the amplitude-adjusted small signal symbol is equal to the power ratio between the large signal and the small signal;

[0094] Secondly, the NOMA signal is obtained by superimposing the small signal symbol after adjusting the amplitude and the large signal symbol;

[0095] Finally, the NOMA signal is filtered and output as a digital signal at the transmitting end;

[0096] Step S3-2: resample, digital-to-analog convert, and electro-optical modulate the transmitting end digital signal in sequence to convert it into the transmitting end optical signal.

[0097] Step S4: On the optical network unit side, the transmitting end optical signal is restored to a NOMA signal, which is recorded as the receiving end NOMA signal;

[0098] Wherein, the step S4 specifically includes:

[0099] Step S4-1, performing photoelectric detection, analog-to-digital conversion, and resampling on the transmitting end optical signal in sequence to obtain a receiving end digital signal;

[0100] Step S4-2: performing channel equalization on the receiving end digital signal after matched filtering to recover the receiving end NOMA signal.

[0101] Step S5: According to the signal allocation result of step S2, the optical network unit allocated to the large signal recovers the large signal from the receiving end NOMA signal through continuous interference cancellation of hard decision;

[0102] Among them, since the power of the large signal is greater than that of the small signal, the small signal is regarded as interference noise when the NOMA signal is directly hard-determined at the receiving end, and the hard decision is the large signal.

[0103] Moreover, step S5 can be stopped after recovering the large signal. On the one hand, this is because the small signal is not the signal required by the optical network unit allocated to the large signal, and the small signal can be discarded; on the other hand, stopping to recover the small signal from the NOMA signal at the receiving end can avoid wasting DSP resources.

[0104] Step S6: According to the signal allocation result of step S2, the optical network unit allocated to the small signal recovers the small signal from the receiving end NOMA signal.

[0105] Preferably, the step S6 recovers the small signal by any one of the following two methods:

[0106] Method 1: The optical network unit assigned to the small signal first performs a hard decision on the receiving end NOMA signal, then performs bit-symbol mapping to obtain a reconstructed large signal, and finally subtracts the receiving end NOMA signal from the reconstructed large signal to recover the small signal;

[0107] Method 2: The optical network unit assigned to the small signal first makes a soft decision on the receiving end NOMA signal, then performs LDPC iterative decoding (LDPC stands for low-density parity check), and then obtains the corrected large signal through bit-symbol mapping. Finally, the receiving end NOMA signal is subtracted from the corrected large signal to recover the small signal. Therefore, due to the continuous interference cancellation assisted by LDPC, a more accurate corrected large signal can be reconstructed to reduce the noise generated by large signal decision errors, thereby improving the performance of the recovered small signal and reducing the performance cost of the small signal.

[0108] Therefore, the present invention prioritizes allocating small signals that require greater received power to restore the signal to the optical network units with the highest power margin, and then allocates large signals that require relatively smaller received power to restore the signal to the remaining optical network units, so as to fully utilize the power margin of all optical network units and improve the overall transmission rate of the communication network.

[0109] In addition, the present invention superimposes and encodes the large signal and the small signal to generate a NOMA signal and transmits it to the optical network unit side via the optical fiber channel. Since the time domain characteristics of the small signal are disrupted by the scrambling operation on the optical line terminal side, the characteristics of the small signal in the time domain are similar to Gaussian white noise, and thus the NOMA signal obtained by superimposing and encoding it with the large signal can meet the eye diagram template of the original speed signal, that is, the large signal; thus, according to the signal allocation result, the small signal and the large signal are respectively recovered from the NOMA signal at the receiving end using the corresponding optical network unit;

[0110] In summary, the present invention can improve the overall transmission rate of the communication network while meeting the eye diagram template of the original rate signal at a lower performance cost.

[0111] The following experiments are conducted using an OOK signal as the large signal and a DMT signal or an OOK signal or other signals as the small signal to illustrate the technical effects of the present invention:

[0112] Figure 4 The figure shows the probability density function of the NOMA signal without shaping filtering in step S3-1. As can be seen from the figure:

[0113] The probability density function of the small signal superimposed on the large signal is similar to Gaussian white noise, and the probability density function of the obtained NOMA signal still presents an OOK distribution. Therefore, the time domain characteristics of the small signal are disrupted by the scrambling operation, presenting a distribution characteristic similar to Gaussian white noise, making the small signal not easily detected by a third party, thereby achieving the purpose of private speedup.

[0114] Figure 5 The figure shows the eye diagram of the NOMA signal without shaping filtering described in step S3-1. As can be seen in the figure:

[0115] Since the frequency domain scrambling of the small signal in step S3-1 disrupts the time domain characteristics of the small signal, the characteristics of the small signal in the time domain are similar to Gaussian white noise. The eye diagram of the obtained NOMA signal conforms to the OOK eye diagram template, which can achieve the purpose of private speedup.

[0116] Figure 6 The figure shows the power ratio between the large signal and the small signal obtained by using hard decision continuous interference cancellation and LDPC-assisted continuous interference cancellation and the original rate signal, when the number of repetitions n is 8 and the clipping ratio is -3dB, and the received optical power difference is shown in the figure. As can be seen in the figure:

[0117] When the power ratio is optimized at 11dB, the received optical power difference between the large signal and the original rate signal obtained using hard-decision continuous interference cancellation is 2dB, and the received optical power difference between the small signal and the original rate signal is 4.4dB. Furthermore, using LDPC-assisted continuous interference cancellation, the received optical power difference between the small signal and the original rate signal is 2.9dB. The received optical power difference, or performance penalty, refers to the difference in received optical power required for the bit error rate (BER) of the NOMA signal (a large-signal superimposed small signal) to reach the 20% soft-decision forward error correction threshold compared to the original rate signal under the same channel conditions. LDPC-assisted continuous interference cancellation improves the decision accuracy of large signals through LDPC iterative decoding, reduces the noise generated by large signal decision errors, and thus improves the decision accuracy of small signals, thereby reducing the performance penalty for small signals. This demonstrates that the present invention can achieve private speedup at a low performance cost and can optimize the performance penalty between large and small signals in NOMA and the original rate signal by adjusting the clipping ratio and power ratio. The system bit error rate curve demonstrates the feasibility of the above system.

[0118] Figure 7The figure shows the power ratio between the large signal and the small signal obtained by using hard decision continuous interference cancellation and LDPC-assisted continuous interference cancellation and the original rate signal when the OOK signal is used as the repetition number n=8, which is a graph of the received optical power difference. As can be seen in the figure:

[0119] When the power ratio is preferably 9dB, there is a 2.7dB difference in received optical power between the large signal and the original rate signal obtained by using the continuous interference cancellation of hard decision, and a 4.4dB difference in received optical power between the small signal and the original rate signal. Further, there is a 3dB difference in received optical power between the small signal and the original rate signal obtained by using the continuous interference cancellation assisted by LDPC. LDPC-assisted continuous interference cancellation improves the decision accuracy of large signals through LDPC iterative decoding, reduces the noise generated by errors in large signal decisions, and thus improves the decision accuracy of small signals, achieving the purpose of reducing the performance cost of small signals. This shows that the present invention can achieve the purpose of private speed-up at a lower performance cost and can optimize the performance cost between large signals and small signals and the original rate signal in NOMA by adjusting the clipping ratio and power ratio. The system bit error rate curve shows that the above system is indeed feasible.

[0120] Therefore, by Figures 4 to 7 The results shown can prove that a communication network speed-up method of the present invention can meet the original speed signal eye diagram template at a lower performance cost while increasing the rate, thereby achieving the purpose of private speed-up, and can optimize the performance cost between large signals and small signals in NOMA and the original speed signal by adjusting the clipping ratio and power ratio.

[0121] The above-mentioned experiments have proved that a method for increasing the speed of a communication network of the present invention can achieve the function of satisfying the original speed signal eye diagram template at a lower performance cost while increasing the speed by rationally utilizing the optical network unit with sufficient power margin. Therefore, the scrambling operation of the small signal at the transmitting end of the present invention disrupts the time domain characteristics of the small signal, so that the characteristics of the small signal in the time domain are similar to Gaussian white noise, and the NOMA signal can pass the original speed signal eye diagram template. LDPC-assisted continuous interference elimination technology is adopted at the receiving end, and a small number of LDPC iterative decoding of the large signal is performed to improve the accuracy of the reconstructed large signal, reduce the noise generated by the error in the judgment of the large signal, and thus improve the accuracy of the small signal judgment and reduce the performance cost. Therefore, a method for increasing the speed of a communication network of the present invention can satisfy the original speed signal eye diagram template at a lower performance cost while increasing the speed.

[0122] Example 2

[0123] like Figure 3 As shown, the present invention also discloses a communication network speed-up system, comprising: a speed-up sending system and a speed-up receiving system;

[0124] The speed-up sending system includes:

[0125] A speed-up signal generating unit is configured to generate a NOMA signal that can pass through the eye diagram template of the original speed signal from the original speed signal and the speed-up signal, and the NOMA signal is output as a transmitting end digital signal after shaping filtering;

[0126] A digital-to-analog converter, configured to convert the digital signal from the transmitting end into an analog signal through digital-to-analog conversion;

[0127] an electro-optical modulator, configured to electro-optically modulate the analog signal and convert it into a transmitting optical signal so as to be transmitted to the optical network unit side via an optical fiber;

[0128] Wherein, the speed-up signal generating unit includes:

[0129] The optical network unit power margin calculation subunit is used to measure the power budget of the original speed signal and the link attenuation between each optical network unit (ONU) and the optical line terminal (OLT) on the optical network unit side to calculate the power margin of each optical network unit;

[0130] The optical network unit allocation subunit is used to allocate an original speed signal and a speed-up signal that need to be transmitted to the optical network unit side according to the power margin of each optical network unit on the optical line terminal side, and record the original speed signal with larger power as a large signal and the speed-up signal with smaller power as a small signal; wherein the specific method of signal allocation is as follows: first, obtain the power margin of each optical network unit calculated in step S1, and sort the optical network units from large to small according to the power margin; then, first allocate the small signal to several optical network units with the highest power margin, and then allocate the large signal to the optical network units. The numbers are distributed to the remaining optical network units so that all optical network units evenly distribute the small signal and the large signal; for example: assuming that the data volume of the small signal and the large signal are 6G and 50G respectively, and there are 56 optical network units on the optical network unit side, each optical network unit should evenly distribute the signal with a data volume of 1G, that is: the optical network units are sorted from large to small according to the power margin and numbered 1 to 56, then in step S2-2, the small signal should first be evenly divided into 6 parts and then distributed to optical network units No. 1 to 6 in sequence, and then the large signal should be evenly divided into 50 parts and then distributed to optical network units No. 7 to 56 in sequence.

[0131] A NOMA signal generation subunit is configured to generate, on the optical line terminal side, a NOMA signal (i.e., a non-orthogonal multiple access signal) obtained by superimposing and encoding the large signal and the scrambled small signal based on the power ratio and clipping ratio of the small signal;

[0132] Preferably, the NOMA signal generating subunit generates the NOMA signal in the following manner:

[0133] First, the bit sequence of the large signal and the bit sequence of the small signal are respectively subjected to LDPC encoding and then bit-to-symbol mapping to obtain large signal symbols and small signal symbols;

[0134] Secondly, the small signal symbol is repeated several times so that the data length of the repeated small signal symbol is consistent with that of the large signal symbol. For example, assuming that the small signal symbol is [1 -1 1 1], its data length is 4, and the data length of the large signal symbol is 12, the small signal symbol needs to be repeatedly encoded three times, and the repeated small signal symbol is [11 1 -1-1 -1 1 1 1 1 1 1].

[0135] Secondly, the repeated small signal symbols are scrambled to disrupt their time domain characteristics;

[0136] Preferably, the method for scrambling the repeated small signal symbols is as follows: according to the modulation format of the small signal, a group of random π / 2 phases or a group of random ±1 sequences are selected to multiply the small signal symbols to achieve scrambling of the small signal symbols, thereby disrupting the time domain characteristics of the small signal, so that the characteristics of the small signal in the time domain are similar to Gaussian white noise.

[0137] Secondly, the scrambled small signal symbol is amplitude-adjusted so that the power ratio between the large signal symbol and the amplitude-adjusted small signal symbol is equal to the power ratio between the large signal and the small signal;

[0138] Finally, the NOMA signal is obtained by superimposing and encoding the small signal symbol after adjusting the amplitude and the large signal symbol.

[0139] The speed-up receiving system comprises:

[0140] The photoelectric detector is used to perform photoelectric detection on the optical network unit side on the sending end optical signal transmitted from the optical line terminal side through the optical fiber to obtain the receiving end analog electrical signal;

[0141] An analog-to-digital converter, configured to convert the analog electrical signal of the receiving end into a digital signal of the receiving end;

[0142] A speed-up signal recovery unit, configured to recover a large signal and a small signal from the receiving end digital signal;

[0143] Wherein, the speed-up signal recovery unit includes:

[0144] A NOMA signal recovery subunit, configured to sequentially perform matched filtering and channel equalization on the receiving end digital signal to recover a receiving end NOMA signal;

[0145] The large signal recovery subunit is configured to recover the large signal from the receiving-end NOMA signal by performing continuous interference elimination through hard decision according to the signal allocation result of the optical network unit allocation subunit. Since the power of the large signal is greater than that of the small signal, the small signal is treated as interference noise when the receiving-end NOMA signal is directly hard-determined, and the hard decision is the large signal. Furthermore, step S5 can be stopped after recovering the large signal. On the one hand, this is because the small signal is not the signal required by the optical network unit allocated to the large signal and can be discarded. On the other hand, stopping the recovery of the small signal from the receiving-end NOMA signal can avoid wasting DSP resources.

[0146] The small signal recovery subunit is used to recover the small signal from the receiving end NOMA signal of the optical network unit allocated to the small signal according to the signal allocation result of the optical network unit allocation subunit.

[0147] Preferably, the small signal recovery subunit recovers the small signal by any one of the following two methods:

[0148] Method 1: The optical network unit assigned to the small signal first performs a hard decision on the receiving end NOMA signal, then performs bit-symbol mapping to obtain a reconstructed large signal, and finally subtracts the receiving end NOMA signal from the reconstructed large signal to recover the small signal;

[0149] Method 2: The optical network unit assigned to the small signal first makes a soft decision on the receiving end NOMA signal, then performs LDPC iterative decoding (LDPC stands for low-density parity check), and then obtains the corrected large signal through bit-symbol mapping. Finally, the receiving end NOMA signal is subtracted from the corrected large signal to recover the small signal. Therefore, due to the continuous interference cancellation assisted by LDPC, a more accurate corrected large signal can be reconstructed to reduce the noise generated by large signal decision errors, thereby improving the performance of the recovered small signal and reducing the performance cost of the small signal.

[0150] Therefore, the present invention prioritizes allocating small signals that require greater received power to restore the signal to the optical network units with the highest power margin, and then allocates large signals that require relatively smaller received power to restore the signal to the remaining optical network units, so as to fully utilize the power margin of all optical network units and improve the overall transmission rate of the communication network.

[0151] In addition, the present invention superimposes and encodes the large signal and the small signal to generate a NOMA signal and transmits it to the optical network unit side via the optical fiber channel. Since the time domain characteristics of the small signal are disrupted by the scrambling operation on the optical line terminal side, the characteristics of the small signal in the time domain are similar to Gaussian white noise, and thus the NOMA signal obtained by superimposing and encoding it with the large signal can meet the eye diagram template of the original speed signal, that is, the large signal; thus, according to the signal allocation result, the small signal and the large signal are respectively recovered from the NOMA signal at the receiving end using the corresponding optical network unit;

[0152] In summary, the present invention can improve the overall transmission rate of the communication network while meeting the eye diagram template of the original rate signal at a lower performance cost.

[0153] The experiment described in the above embodiment 1 using the OOK signal as the large signal and the DMT signal or OOK signal and other signals as the small signal, its experimental process and experimental results are also applicable to the communication network speed-up system of the present invention, and will not be repeated here.

[0154] The present invention is not limited to the above-mentioned specific implementation methods. According to the above content, in accordance with the common technical knowledge and customary means in this field, without departing from the above-mentioned basic technical ideas of the present invention, the present invention can also make other various forms of equivalent modifications, replacements or changes, all of which fall within the scope of protection of the present invention.

Claims

1. A method for increasing the speed of a communication network, characterized in that: include: Step S1: On the optical network unit side, measure the power budget of the optical network unit for the original speed signal and the link attenuation between each optical network unit on the optical network unit side and the optical line terminal to calculate the power margin of each optical network unit; Step S2: At the optical line terminal side, according to the power margin of each optical network unit, an original speed signal and a speed-up signal to be transmitted to the optical network unit side are allocated, and the original speed signal with larger power is recorded as a large signal, and the speed-up signal with smaller power is recorded as a small signal. Specifically, the steps include: Step S2-1, obtaining the power margin of each optical network unit calculated in step S1, and sorting the optical network units from large to small according to the power margin; Step S2-2: first distribute the small signal to several optical network units with the highest power margin ranking, and then distribute the large signal to the remaining optical network units, so that all optical network units evenly distribute the small signal and the large signal; Step S3: On the optical line terminal side, based on the power ratio and clipping ratio of the small signal, a NOMA signal is generated by superimposing and encoding the large signal and the scrambled small signal, and the NOMA signal is converted into a transmitting end optical signal after shaping and filtering to be transmitted to the optical network unit side via the optical fiber. Step S4: On the optical network unit side, the transmitting end optical signal is restored to a NOMA signal, which is recorded as the receiving end NOMA signal; Step S5: According to the signal allocation result of step S2, the optical network unit allocated to the large signal recovers the large signal from the receiving end NOMA signal through continuous interference cancellation of hard decision; Step S6: According to the signal allocation result of step S2, the optical network unit allocated to the small signal recovers the small signal from the receiving end NOMA signal.

2. The method for increasing the speed of a communication network according to claim 1, wherein: The step S3 specifically includes: Step S3-1: First, the bit sequence of the large signal and the bit sequence of the small signal are respectively subjected to LDPC encoding and then bit-to-symbol mapping to obtain a large signal symbol and a small signal symbol; Secondly, the small signal symbol is repeated several times so that the data length of the repeated small signal symbol is consistent with that of the large signal symbol; Secondly, the repeated small signal symbols are scrambled to disrupt their time domain characteristics; Secondly, the scrambled small signal symbol is amplitude-adjusted so that the power ratio between the large signal symbol and the amplitude-adjusted small signal symbol is equal to the power ratio between the large signal and the small signal; Secondly, the NOMA signal is obtained by superimposing the small signal symbol after adjusting the amplitude and the large signal symbol; Finally, the NOMA signal is filtered and output as a digital signal at the transmitting end; Step S3-2: resample, digital-to-analog convert, and electro-optical modulate the transmitting end digital signal in sequence to convert it into the transmitting end optical signal.

3. The method for increasing the speed of a communication network according to claim 2, wherein: In step S3-1, the repeated small signal symbols are scrambled by selecting a set of random π / 2 phases or a set of random ±1 sequences to multiply the small signal symbols according to the modulation format of the small signal to achieve scrambling of the small signal symbols.

4. The method for increasing the speed of a communication network according to any one of claims 1 to 3, characterized in that: The step S4 specifically includes: Step S4-1, performing photoelectric detection, analog-to-digital conversion, and resampling on the transmitting end optical signal in sequence to obtain a receiving end digital signal; Step S4-2: performing channel equalization on the receiving end digital signal after matched filtering to recover the receiving end NOMA signal.

5. The method for increasing the speed of a communication network according to any one of claims 1 to 3, characterized in that: Step S6 recovers the small signal by any one of the following two methods: Method 1: The optical network unit assigned to the small signal first performs a hard decision on the receiving end NOMA signal, then performs bit-symbol mapping to obtain a reconstructed large signal, and finally subtracts the receiving end NOMA signal from the reconstructed large signal to recover the small signal; Method 2: The optical network unit assigned to the small signal first makes a soft decision on the receiving end NOMA signal, then performs LDPC iterative decoding, and then obtains the corrected large signal through bit-symbol mapping. Finally, the receiving end NOMA signal is subtracted from the corrected large signal to restore the small signal.

6. A communication network speed-up system, characterized in that: include: Speed-up sending system and speed-up receiving system; The speed-up sending system includes: A speed-up signal generating unit is configured to generate a NOMA signal that can pass through the eye diagram template of the original speed signal from the original speed signal and the speed-up signal, and the NOMA signal is output as a transmitting end digital signal after shaping filtering; A digital-to-analog converter, configured to convert the digital signal from the transmitting end into an analog signal through digital-to-analog conversion; an electro-optical modulator, configured to electro-optically modulate the analog signal and convert it into a transmitting optical signal so as to be transmitted to the optical network unit side via an optical fiber; Wherein, the speed-up signal generating unit includes: The optical network unit power margin calculation subunit is used to measure the power budget of the original speed signal and the link attenuation between each optical network unit and the optical line terminal on the optical network unit side, so as to calculate the power margin of each optical network unit; The optical network unit allocation subunit is used to allocate, on the optical line terminal side, an original speed signal and a speed-up signal that need to be transmitted to the optical network unit side according to the power margin of each optical network unit, and record the original speed signal with larger power as a large signal and the speed-up signal with smaller power as a small signal; wherein the specific method of signal allocation is as follows: first, obtain the power margin of each optical network unit calculated in step S1, and sort the optical network units from large to small according to the power margin; then, first allocate the small signal to several optical network units with the highest power margin, and then allocate the large signal to the remaining optical network units, so that all optical network units evenly distribute the small signal and the large signal; A NOMA signal generating subunit is configured to generate, at the optical line terminal side, a NOMA signal obtained by superimposing and encoding the large signal and the scrambled small signal based on the power ratio and clipping ratio of the small signal; The speed-up receiving system comprises: The photoelectric detector is used to perform photoelectric detection on the optical network unit side on the sending end optical signal transmitted from the optical line terminal side through the optical fiber to obtain the receiving end analog electrical signal; An analog-to-digital converter, configured to convert the analog electrical signal of the receiving end into a digital signal of the receiving end; A speed-up signal recovery unit, configured to recover a large signal and a small signal from the receiving end digital signal; Wherein, the speed-up signal recovery unit includes: A NOMA signal recovery subunit, configured to sequentially perform matched filtering and channel equalization on the receiving end digital signal to recover a receiving end NOMA signal; A large signal recovery subunit is configured to recover the large signal from the receiving end NOMA signal by performing continuous interference cancellation of hard decision on the optical network unit allocated to the optical network unit according to the signal allocation result of the optical network unit allocation subunit; The small signal recovery subunit is used to recover the small signal from the receiving end NOMA signal of the optical network unit allocated to the small signal according to the signal allocation result of the optical network unit allocation subunit.

7. The communication network speed-up system according to claim 6, characterized in that: The NOMA signal generating subunit generates the NOMA signal in the following manner: First, the bit sequence of the large signal and the bit sequence of the small signal are respectively subjected to LDPC encoding and then bit-to-symbol mapping to obtain large signal symbols and small signal symbols; Secondly, the small signal symbol is repeated several times so that the data length of the repeated small signal symbol is consistent with that of the large signal symbol; Secondly, the repeated small signal symbols are scrambled to disrupt their time domain characteristics; Secondly, the scrambled small signal symbol is amplitude-adjusted so that the power ratio between the large signal symbol and the amplitude-adjusted small signal symbol is equal to the power ratio between the large signal and the small signal; Finally, the NOMA signal is obtained by superimposing and encoding the small signal symbol after adjusting the amplitude and the large signal symbol.

8. The communication network speed-up system according to claim 7, characterized in that: The method of scrambling the repeated small signal symbols is as follows: according to the modulation format of the small signal, a group of random π / 2 phases or a group of random ±1 sequences are selected to multiply the small signal symbols to achieve scrambling of the small signal symbols.

9. The communication network speed-up system according to any one of claims 6 to 8, characterized in that: The small signal recovery subunit recovers the small signal in any one of the following two ways: Method 1: The optical network unit assigned to the small signal first performs a hard decision on the receiving end NOMA signal, then performs bit-symbol mapping to obtain a reconstructed large signal, and finally subtracts the receiving end NOMA signal from the reconstructed large signal to recover the small signal; Method 2: The optical network unit assigned to the small signal first makes a soft decision on the receiving end NOMA signal, then performs LDPC iterative decoding, and then obtains the corrected large signal through bit-symbol mapping. Finally, the receiving end NOMA signal is subtracted from the corrected large signal to restore the small signal.

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