Fractional order digital-analog hybrid forward pass method and system

Abstract

The invention provides a fractional order digital-analog hybrid forward transmission method and system, and the method comprises the steps: a signal processing and transmitting step: at a transmitting end, splitting a wireless signal into two parts, carrying out different-order digital-analog hybrid modulation on the two parts, and then carrying out frequency division multiplexing to realize fractional-multiple bandwidth expansion; and a signal receiving and processing step: at a receiving end, demodulating the two parts of different-order digital-analog hybrid radio-over-fiber signals, and recovering a wireless signal. According to the invention, by adopting fractional order digital-analog hybrid modulation, the problem that general digital-analog hybrid modulation can only realize integral multiple bandwidth expansion is solved, and the effect of improving the flexibility of a forward transmission system is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of digital analog hybrid fronthaul, and in particular to a fractional-order digital analog hybrid fronthaul method and system. Background Art

[0002] Mobile fronthaul ensures the connection between the optical core network and the wireless mobile network. Its purpose is to transmit wireless signals between the baseband processing unit and the remote wireless unit. In order to meet the large capacity and high fidelity requirements of the fronthaul link, signal-to-noise ratio and spectrum efficiency are key performance indicators for measuring wireless over fiber technology. Hybrid digital-analog wireless over fiber technology achieves a good compromise between signal-to-noise ratio and spectrum efficiency by splitting the wireless signal into two parts, digital and analog signals, and multiplexing them for transmission. However, it lacks flexibility. How to flexibly adjust the bandwidth expansion of the wireless signal according to the bandwidth of the actual optical fiber system is still an important issue.

[0003] Patent document CN117061005A (application number: 202311070264.X) discloses a digital analog fronthaul system. This method places the modulated digital symbols and analog symbols alternately in time, and uses the damage estimated from the digital symbols at the receiving end to directly compensate for the damage of the analog signal, thereby improving the ability to compensate for the damage of the analog signal. However, this patent can only achieve integer multiple bandwidth expansion, and cannot be adjusted according to the actual bandwidth of the optical fiber transmission system. It lacks flexibility and cannot completely solve the above technical problems. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a fractional-order digital analog hybrid forward transmission method and system.

[0005] The fractional-order digital analog hybrid forward transmission method provided by the present invention includes:

[0006] Signal processing and transmission steps: At the transmitting end, the wireless signal is split into two parts, the two parts are modulated with different orders of digital-analog hybrid, and then frequency-division multiplexed to achieve fractional bandwidth expansion;

[0007] Signal reception and processing steps: At the receiving end, the two parts of the mixed digital-analog optical wireless signals of different orders are demodulated to restore the wireless signal.

[0008] Preferably, the signal processing and transmitting step comprises:

[0009] Step 1: Perform frequency domain carrier aggregation on wireless signals from different channels in the frequency domain and normalize them to obtain aggregated wireless sampling point signals;

[0010] Step 2: Split the aggregated wireless sampling point signal into a first part and a second part of wireless signals;

[0011] Step 3: Perform N1-order and N2-order digital-analog mixed modulation on the first part and the second part of the wireless signal respectively, and perform time division multiplexing on each of them to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal;

[0012] Step 4: pulse shaping the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, scaling the N1-order digital-analog mixed signal, and then frequency division multiplexing the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal to obtain a fractional-order digital-analog mixed signal;

[0013] Step 5: The fractional-order digital-analog mixed signal is subjected to electro-optical conversion, and then the fractional-order digital-analog mixed optical signal is transmitted through an optical fiber.

[0014] Preferably, the signal receiving and processing step comprises:

[0015] Step 6: The fractional-order digital-analog mixed optical signal after optical fiber transmission is subjected to photoelectric conversion through a photodiode to obtain an electrical signal, and then the electrical signal is sampled to obtain a fractional-order digital-analog mixed signal with noise at the receiving end;

[0016] Step 7: normalize and frequency divide and multiplex the fractional-order digital-analog mixed signal with noise at the receiving end to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal with noise at the receiving end;

[0017] Step 8: Time division multiplexing is performed on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal with noise at the receiving end, and the first part and the second part of the wireless signal of the receiving end are obtained by N1-order and N2-order digital-analog mixed demodulation;

[0018] Step 9: recombining the first part and the second part of the wireless signal of the receiving end to recover the aggregated wireless sampling point signal;

[0019] Step 10: Carrier de-aggregate the aggregated wireless sampling point signals and allocate them to corresponding channels.

[0020] Preferably, the step 2 comprises:

[0021] Step 2.1: Select a target bandwidth expansion factor and use R t Indicates that R t is a rational number greater than 2 and is a non-integer;

[0022] Step 2.2: According to the target bandwidth expansion multiple, the ratio of the sequence length of the first part and the second part of the wireless signal to the sequence length of the entire aggregated wireless sampling point signal is:

[0023]

[0024] Wherein, p represents the ratio of the sequence length of the first part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, q represents the ratio of the sequence length of the second part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, It means to round a number to an integer less than or equal to itself. Indicates rounding a number to an integer greater than or equal to itself;

[0025] Step 2.3: According to the calculated ratios p and q of the sequence lengths of the first and second parts of the wireless signals to the sequence lengths of the entire aggregated wireless sampling point signal, the aggregated wireless sampling point signal is divided into two parts to obtain the first and second parts of the wireless signals.

[0026] Preferably, the step 3 comprises:

[0027] Step 3.1: According to the target bandwidth extension multiple, the digital-analog hybrid modulation orders N1 and N2 of the first and second wireless signals are calculated, and the expressions are as follows:

[0028]

[0029] Step 3.2: Perform N1-order digital-analog hybrid modulation on the first part of the wireless signal, that is, divide the first part of the wireless signal into N1 segments of digital signals and 1 segment of analog signals through N1 rounding operations, and then perform time-division multiplexing on the N1+1 segments of signals to obtain an N1-order digital-analog hybrid signal; perform N2-order digital-analog hybrid modulation on the second part of the wireless signal, that is, divide the second part of the wireless signal into N2 segments of digital signals and 1 segment of analog signals through N2 rounding operations, and then perform time-division multiplexing on the N2+1 segments of signals to obtain an N2-order digital-analog hybrid signal.

[0030] The fractional-order digital analog hybrid fronthaul system provided by the present invention comprises:

[0031] Signal processing and transmission module: At the transmitting end, the wireless signal is split into two parts, which are modulated with different orders of digital-analog hybrid modulation and then frequency-division multiplexed to achieve fractional bandwidth expansion;

[0032] Signal receiving and processing module: At the receiving end, the two parts of the mixed digital-analog optical wireless signals of different orders are demodulated to restore the wireless signal.

[0033] Preferably, the signal processing and transmitting module includes:

[0034] Module M1: Perform frequency domain carrier aggregation on wireless signals from different channels in the frequency domain and normalize them to obtain aggregated wireless sampling point signals;

[0035] Module M2: splitting the aggregated wireless sampling point signal into a first part and a second part of wireless signals;

[0036] Module M3: performing N1-order and N2-order digital-analog mixed modulation on the first and second wireless signals respectively, and performing time division multiplexing on each of them to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal;

[0037] Module M4: pulse shaping the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, scaling the N1-order digital-analog mixed signal, and then frequency division multiplexing the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal to obtain a fractional-order digital-analog mixed signal;

[0038] Module M5: converts the fractional-order digital-analog mixed signal into an electro-optical signal, and then transmits the fractional-order digital-analog mixed optical signal through an optical fiber.

[0039] Preferably, the signal receiving and processing module comprises:

[0040] Module M6: converts the fractional-order digital-analog mixed optical signal after optical fiber transmission into an electrical signal through a photodiode, and then samples the electrical signal to obtain a fractional-order digital-analog mixed signal with noise at the receiving end;

[0041] Module M7: normalize and frequency-demultiplex the fractional-order digital-analog mixed signal with noise at the receiving end to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal with noise at the receiving end;

[0042] Module M8: performing time division multiplexing on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal with noise at the receiving end, and performing N1-order and N2-order digital-analog mixed demodulation to obtain the first part and the second part of the wireless signal at the receiving end;

[0043] Module M9: recombines the first part and the second part of the wireless signal of the receiving end to recover the aggregated wireless sampling point signal;

[0044] Module M10: Carrier de-aggregation of the aggregated wireless sampling point signals and allocation to corresponding channels.

[0045] Preferably, the module M2 comprises:

[0046] Module M2.1: Select the bandwidth expansion multiple of a certain target, using R t Indicates that R t is a rational number greater than 2 and is a non-integer;

[0047] Module M2.2: According to the target bandwidth expansion multiple, the ratio of the sequence length of the first part and the second part of the wireless signal to the sequence length of the entire aggregated wireless sampling point signal is:

[0048]

[0049] Wherein, p represents the ratio of the sequence length of the first part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, q represents the ratio of the sequence length of the second part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, It means to round a number to an integer less than or equal to itself. Indicates rounding a number to an integer greater than or equal to itself;

[0050] Module M2.3: According to the calculated ratios p and q of the sequence lengths of the first and second parts of the wireless signals to the sequence lengths of the entire aggregated wireless sampling point signal, the aggregated wireless sampling point signal is divided into two parts to obtain the first and second parts of the wireless signals.

[0051] Preferably, the module M3 comprises:

[0052] Module M3.1: According to the target bandwidth expansion multiple, the digital-analog hybrid modulation orders N1 and N2 of the first and second wireless signals are calculated, and the expressions are as follows:

[0053]

[0054] Module M3.2: Perform N1-order digital-analog mixed modulation on the first part of the wireless signal, that is, divide the first part of the wireless signal into N1 segments of digital signals and 1 segment of analog signals through N1 rounding operations, and then perform time-division multiplexing on the N1+1 segments of signals to obtain an N1-order digital-analog mixed signal; perform N2-order digital-analog mixed modulation on the second part of the wireless signal, that is, divide the second part of the wireless signal into N2 segments of digital signals and 1 segment of analog signals through N2 rounding operations, and then perform time-division multiplexing on the N2+1 segments of signals to obtain an N2-order digital-analog mixed signal.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] (1) The present invention solves the problem that general digital-analog hybrid modulation can only achieve integer multiple bandwidth expansion by adopting fractional-order digital-analog hybrid modulation, thereby achieving the effect of improving the flexibility of the fronthaul system;

[0057] (2) The present invention solves the problem of low efficiency of signal-to-noise ratio as bandwidth increases by optimizing the power of two parts of different-order digital-analog mixed signals, and achieves an effect of approximately linear signal-to-noise ratio growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0059] Figure 1 This is the flow chart of the transmitter of the fractional-order digital analog hybrid fronthaul system;

[0060] Figure 2 This is the flow chart of the receiving end of the fractional-order digital analog hybrid fronthaul system;

[0061] Figure 3 It is the spectrum diagram of fractional-order digital-analog mixed signal. DETAILED DESCRIPTION

[0062] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0063] Example 1

[0064] The present invention provides a fractional-order digital analog hybrid forward transmission method, comprising:

[0065] Signal processing and transmission steps: At the transmitting end, the wireless signal is split into two parts, the two parts are modulated with different orders of digital-analog hybrid, and then frequency-division multiplexed to achieve fractional bandwidth expansion;

[0066] Signal reception and processing steps: At the receiving end, the two parts of the mixed digital-analog optical wireless signals of different orders are demodulated to restore the wireless signal.

[0067] like Figure 1 , the signal processing and transmitting steps include:

[0068] Step 1: Perform frequency domain carrier aggregation on wireless signals from different channels in the frequency domain and normalize them to obtain aggregated wireless sampling point signals;

[0069] Step 2: Split the aggregated wireless sampling point signal into a first part and a second part of wireless signals;

[0070] Step 3: Perform N1-order and N2-order digital-analog mixed modulation on the first part and the second part of the wireless signal respectively, and perform time division multiplexing on each of them to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal;

[0071] Step 4: pulse shaping the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, scaling the N1-order digital-analog mixed signal, and then frequency division multiplexing the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal to obtain a fractional-order digital-analog mixed signal;

[0072] Step 5: The fractional-order digital-analog mixed signal is subjected to electro-optical conversion, and then the fractional-order digital-analog mixed optical signal is transmitted through an optical fiber.

[0073] like Figure 2 , the signal receiving and processing steps include:

[0074] Step 6: The fractional-order digital-analog mixed optical signal after optical fiber transmission is subjected to photoelectric conversion through a photodiode to obtain an electrical signal, and then the electrical signal is sampled to obtain a fractional-order digital-analog mixed signal with noise at the receiving end;

[0075] Step 7: normalize and frequency divide and multiplex the fractional-order digital-analog mixed signal with noise at the receiving end to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal with noise at the receiving end;

[0076] Step 8: Time division multiplexing is performed on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal with noise at the receiving end, and the first part and the second part of the wireless signal of the receiving end are obtained by N1-order and N2-order digital-analog mixed demodulation;

[0077] Step 9: recombining the first part and the second part of the wireless signal of the receiving end to recover the aggregated wireless sampling point signal;

[0078] Step 10: Carrier de-aggregate the aggregated wireless sampling point signals and allocate them to corresponding channels.

[0079] The step 2 comprises the following steps:

[0080] Step 2.1: Select a target bandwidth expansion factor and use R t Indicates that R t is a rational number greater than 2 and is a non-integer;

[0081] Step 2.2: According to the target bandwidth expansion multiple, the ratio of the sequence length of the first part and the second part of the wireless signal to the sequence length of the entire aggregated wireless sampling point signal is:

[0082]

[0083] Wherein, p represents the ratio of the sequence length of the first part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, q represents the ratio of the sequence length of the second part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, It means to round a number to an integer less than or equal to itself. Indicates rounding a number to an integer greater than or equal to itself;

[0084] Step 2.3: According to the calculated ratios p and q of the sequence lengths of the first and second parts of the wireless signals to the sequence lengths of the entire aggregated wireless sampling point signal, the aggregated wireless sampling point signal is divided into two parts to obtain the first and second parts of the wireless signals.

[0085] The step 3 comprises the following steps:

[0086] Step 3.1: According to the target bandwidth extension multiple, the digital-analog hybrid modulation orders N1 and N2 of the first and second wireless signals are calculated, and the expressions are as follows:

[0087]

[0088] Step 3.2: Perform N1-order digital-analog hybrid modulation on the first part of the wireless signal, that is, divide the first part of the wireless signal into N1 segments of digital signals and 1 segment of analog signals through N1 rounding operations, and then perform time-division multiplexing on the N1+1 segments of signals to obtain an N1-order digital-analog hybrid signal; perform N2-order digital-analog hybrid modulation on the second part of the wireless signal, that is, divide the second part of the wireless signal into N2 segments of digital signals and 1 segment of analog signals through N2 rounding operations, and then perform time-division multiplexing on the N2+1 segments of signals to obtain an N2-order digital-analog hybrid signal.

[0089] Figure 3 The spectrum of the fractional-order digital-analog mixed signal after frequency division multiplexing is presented. The power of the two subcarriers is optimized. The first subcarrier is a 1st-order digital-analog mixed signal, and the second subcarrier is a 2nd-order digital-analog mixed signal.

[0090] Example 2

[0091] The present invention also provides a fractional-order digital analog hybrid fronthaul system, which can be implemented by executing the process steps of the fractional-order digital analog hybrid fronthaul method, that is, technical personnel in this field can understand the fractional-order digital analog hybrid fronthaul method as a preferred implementation of the fractional-order digital analog hybrid fronthaul system.

[0092] The fractional-order digital-analog hybrid fronthaul system provided by the present invention includes: a signal processing and transmitting module: at the transmitting end, the wireless signal is split into two parts, the two parts are subjected to different orders of digital-analog hybrid modulation, and then frequency division multiplexing is performed to achieve fractional bandwidth expansion; a signal receiving and processing module: at the receiving end, the two parts of different orders of digital-analog hybrid optical wireless signals are demodulated to restore the wireless signal.

[0093] The signal processing and transmission module includes: module M1: performing frequency domain carrier aggregation on wireless signals from different channels in the frequency domain, and performing normalization to obtain aggregated wireless sampling point signals; module M2: performing signal splitting on the aggregated wireless sampling point signals, and dividing them into a first part and a second part of wireless signals; module M3: performing N1-order and N2-order digital-analog mixed modulation on the first part and the second part of the wireless signals, respectively, and performing time division multiplexing on each of them, to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal; module M4: performing pulse shaping on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, scaling the N1-order digital-analog mixed signal, and then performing frequency division multiplexing on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, to obtain a fractional-order digital-analog mixed signal; module M5: performing electro-optical conversion on the fractional-order digital-analog mixed signal, and then transmitting the fractional-order digital-analog mixed optical signal through optical fiber.

[0094] The signal receiving and processing module includes: module M6: performing photoelectric conversion on the fractional-order digital-analog mixed optical signal after optical fiber transmission through a photodiode to obtain an electrical signal, and then sampling the electrical signal to obtain a fractional-order digital-analog mixed signal with noise at the receiving end; module M7: normalizing and frequency-demultiplexing the fractional-order digital-analog mixed signal with noise at the receiving end to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal with noise at the receiving end; module M8: performing time-demultiplexing on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal with noise at the receiving end, and performing N1-order and N2-order digital-analog mixed demodulation to obtain the first part and the second part of the wireless signal at the receiving end; module M9: performing signal reorganization on the first part and the second part of the wireless signal at the receiving end to recover the aggregated wireless sampling point signal; module M10: performing carrier deaggregation on the aggregated wireless sampling point signal and assigning it to the corresponding channel.

[0095] The module M2 includes: Module M2.1: Select a bandwidth expansion multiple of a certain target, using R t Indicates that R t is a rational number greater than 2 and is a non-integer; Module M2.2: According to the target bandwidth expansion multiple, the ratio of the sequence length of the first part and the second part of the wireless signal to the sequence length of the entire aggregated wireless sampling point signal is: Wherein, p represents the ratio of the sequence length of the first part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, q represents the ratio of the sequence length of the second part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, It means to round a number to an integer less than or equal to itself. Indicates rounding a number to an integer greater than or equal to itself; Module M2.3: According to the calculated ratios p and q of the sequence lengths of the first and second parts of the wireless signal to the sequence lengths of the entire aggregated wireless sampling point signal, the aggregated wireless sampling point signal is divided into two parts to obtain the first and second parts of the wireless signal.

[0096] The module M3 includes: module M3.1: according to the target bandwidth expansion multiple, the digital-analog hybrid modulation orders N1 and N2 of the first and second wireless signals are calculated, and the expressions are as follows: Module M3.2: Perform N1-order digital-analog mixed modulation on the first part of the wireless signal, that is, divide the first part of the wireless signal into N1 segments of digital signals and 1 segment of analog signals through N1 rounding operations, and then perform time-division multiplexing on the N1+1 segments of signals to obtain an N1-order digital-analog mixed signal; perform N2-order digital-analog mixed modulation on the second part of the wireless signal, that is, divide the second part of the wireless signal into N2 segments of digital signals and 1 segment of analog signals through N2 rounding operations, and then perform time-division multiplexing on the N2+1 segments of signals to obtain an N2-order digital-analog mixed signal.

[0097] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0098] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A fractional-order digital analog hybrid forward transmission method, characterized in that: include: Signal processing and transmission steps: At the transmitting end, the wireless signal is split into two parts, the two parts are modulated with different orders of digital-analog hybrid, and then frequency-division multiplexed to achieve fractional bandwidth expansion; Signal reception and processing steps: At the receiving end, the two parts of the mixed digital-analog optical wireless signals of different orders are demodulated to restore the wireless signal.

2. The fractional-order digital analog hybrid forward transmission method according to claim 1, characterized in that: The signal processing and transmitting steps include: Step 1: Perform frequency domain carrier aggregation on wireless signals from different channels in the frequency domain and normalize them to obtain aggregated wireless sampling point signals; Step 2: Split the aggregated wireless sampling point signal into a first part and a second part of wireless signals; Step 3: Perform N1-order and N2-order digital-analog mixed modulation on the first part and the second part of the wireless signal respectively, and perform time division multiplexing on each of them to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal; Step 4: pulse shaping the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, scaling the N1-order digital-analog mixed signal, and then frequency division multiplexing the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal to obtain a fractional-order digital-analog mixed signal; Step 5: The fractional-order digital-analog mixed signal is subjected to electro-optical conversion, and then the fractional-order digital-analog mixed optical signal is transmitted through an optical fiber.

3. The fractional-order digital analog hybrid forward transmission method according to claim 2, characterized in that: The signal receiving and processing steps include: Step 6: The fractional-order digital-analog mixed optical signal after optical fiber transmission is subjected to photoelectric conversion through a photodiode to obtain an electrical signal, and then the electrical signal is sampled to obtain a fractional-order digital-analog mixed signal with noise at the receiving end; Step 7: normalize and frequency divide and multiplex the fractional-order digital-analog mixed signal with noise at the receiving end to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal with noise at the receiving end; Step 8: Time division multiplexing is performed on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal with noise at the receiving end, and the first part and the second part of the wireless signal of the receiving end are obtained by N1-order and N2-order digital-analog mixed demodulation; Step 9: recombining the first part and the second part of the wireless signal of the receiving end to recover the aggregated wireless sampling point signal; Step 10: Carrier de-aggregate the aggregated wireless sampling point signals and allocate them to corresponding channels.

4. The fractional-order digital analog hybrid forward transmission method according to claim 3, characterized in that: The step 2 comprises: Step 2.1: Select a target bandwidth expansion factor and use R t Indicates that R t is a rational number greater than 2 and is a non-integer; Step 2.2: According to the target bandwidth expansion multiple, the ratio of the sequence length of the first part and the second part of the wireless signal to the sequence length of the entire aggregated wireless sampling point signal is: Wherein, p represents the ratio of the sequence length of the first part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, q represents the ratio of the sequence length of the second part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, It means to round a number to an integer less than or equal to itself. Indicates rounding a number to an integer greater than or equal to itself; Step 2.3: According to the calculated ratios p and q of the sequence lengths of the first and second parts of the wireless signals to the sequence lengths of the entire aggregated wireless sampling point signal, the aggregated wireless sampling point signal is divided into two parts to obtain the first and second parts of the wireless signals.

5. The fractional-order digital analog hybrid forward transmission method according to claim 4, characterized in that: The step 3 comprises: Step 3.1: According to the target bandwidth extension multiple, the digital-analog hybrid modulation orders N1 and N2 of the first and second wireless signals are calculated, and the expressions are as follows: Step 3.2: Perform N1-order digital-analog hybrid modulation on the first part of the wireless signal, that is, divide the first part of the wireless signal into N1 segments of digital signals and 1 segment of analog signals through N1 rounding operations, and then perform time-division multiplexing on the N1+1 segments of signals to obtain an N1-order digital-analog hybrid signal; perform N2-order digital-analog hybrid modulation on the second part of the wireless signal, that is, divide the second part of the wireless signal into N2 segments of digital signals and 1 segment of analog signals through N2 rounding operations, and then perform time-division multiplexing on the N2+1 segments of signals to obtain an N2-order digital-analog hybrid signal.

6. A fractional-order digital analog hybrid fronthaul system, characterized in that: include: Signal processing and transmission module: At the transmitting end, the wireless signal is split into two parts, which are modulated with different orders of digital-analog hybrid modulation and then frequency-division multiplexed to achieve fractional bandwidth expansion; Signal receiving and processing module: At the receiving end, the two parts of the mixed digital-analog optical wireless signals of different orders are demodulated to restore the wireless signal.

7. The fractional-order digital analog hybrid fronthaul system according to claim 6, characterized in that: The signal processing and transmitting module comprises: Module M1: Perform frequency domain carrier aggregation on wireless signals from different channels in the frequency domain and normalize them to obtain aggregated wireless sampling point signals; Module M2: splitting the aggregated wireless sampling point signal into a first part and a second part of wireless signals; Module M3: performing N1-order and N2-order digital-analog mixed modulation on the first and second wireless signals respectively, and performing time division multiplexing on each of them to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal; Module M4: pulse shaping the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal, scaling the N1-order digital-analog mixed signal, and then frequency division multiplexing the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal to obtain a fractional-order digital-analog mixed signal; Module M5: converts the fractional-order digital-analog mixed signal into an electro-optical signal, and then transmits the fractional-order digital-analog mixed optical signal through an optical fiber.

8. The fractional-order digital analog hybrid fronthaul system according to claim 7, characterized in that: The signal receiving and processing module comprises: Module M6: converts the fractional-order digital-analog mixed optical signal after optical fiber transmission into an electrical signal through a photodiode, and then samples the electrical signal to obtain a fractional-order digital-analog mixed signal with noise at the receiving end; Module M7: normalize and frequency-demultiplex the fractional-order digital-analog mixed signal with noise at the receiving end to obtain an N1-order digital-analog mixed signal and an N2-order digital-analog mixed signal with noise at the receiving end; Module M8: performing time division multiplexing on the N1-order digital-analog mixed signal and the N2-order digital-analog mixed signal with noise at the receiving end, and performing N1-order and N2-order digital-analog mixed demodulation to obtain the first part and the second part of the wireless signal at the receiving end; Module M9: recombines the first part and the second part of the wireless signal of the receiving end to recover the aggregated wireless sampling point signal; Module M10: Carrier de-aggregation of the aggregated wireless sampling point signals and allocation to corresponding channels.

9. The fractional-order digital analog hybrid fronthaul system according to claim 8, characterized in that: The module M2 comprises: Module M2.1: Select the bandwidth expansion multiple of a certain target, using R t Indicates that R t is a rational number greater than 2 and is a non-integer; Module M2.2: According to the target bandwidth expansion multiple, the ratio of the sequence length of the first part and the second part of the wireless signal to the sequence length of the entire aggregated wireless sampling point signal is: Wherein, p represents the ratio of the sequence length of the first part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, q represents the ratio of the sequence length of the second part of the wireless signal to the sequence length of the entire wireless sampling point signal after aggregation, It means to round a number to an integer less than or equal to itself. Indicates rounding a number to an integer greater than or equal to itself; Module M2.3: According to the calculated ratios p and q of the sequence lengths of the first and second parts of the wireless signals to the sequence lengths of the entire aggregated wireless sampling point signal, the aggregated wireless sampling point signal is divided into two parts to obtain the first and second parts of the wireless signals.

10. The fractional-order digital analog hybrid fronthaul system according to claim 9, characterized in that: The module M3 comprises: Module M3.1: According to the target bandwidth expansion multiple, the digital-analog hybrid modulation orders N1 and N2 of the first and second wireless signals are calculated, and the expressions are as follows: Module M3.2: Perform N1-order digital-analog mixed modulation on the first part of the wireless signal, that is, divide the first part of the wireless signal into N1 segments of digital signals and 1 segment of analog signals through N1 rounding operations, and then perform time-division multiplexing on the N1+1 segments of signals to obtain an N1-order digital-analog mixed signal; perform N2-order digital-analog mixed modulation on the second part of the wireless signal, that is, divide the second part of the wireless signal into N2 segments of digital signals and 1 segment of analog signals through N2 rounding operations, and then perform time-division multiplexing on the N2+1 segments of signals to obtain an N2-order digital-analog mixed signal.

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