Digital-analog front-haul system

Abstract

The application discloses a digital-analog front transmission system, which comprises a DSP transmitting end, a DSP receiving end and a time-interleaved digital-analog wireless front transmission architecture. The DSP transmitting end quantitatively modulates a wireless signal to be modulated to obtain a modulated digital symbol and an analog symbol, and performs time-domain interleaving on the modulated digital symbol and the analog symbol through the time-interleaved digital-analog wireless front transmission architecture to obtain an interleaved digital symbol and an analog symbol, wherein the digital symbol and the analog symbol are alternately placed in the time-interleaved digital-analog wireless front transmission architecture. The DSP receiving end performs decision recovery on the interleaved digital symbol and the analog symbol to obtain a wireless signal. Since the digital symbol and the analog symbol are alternately placed and time-domain interleaved through the time-interleaved digital-analog wireless front transmission architecture, the damage estimated from the digital symbol can be directly used for compensating the damage of the analog signal to obtain the wireless signal in the DSP receiving end, so that dynamic damage compensation of the analog symbol is realized.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and more particularly to a digital-analog fronthaul system. Background Technology

[0002] With the rapid development of fifth-generation (5G) mobile communication, for mobile fronthaul networks, Radio over Fiber (RoF) technology can be used to transmit wireless signals from the baseband unit (BBU) to the remote radio unit (RRU), supporting multiple mobile users. Traditional fronthaul solutions include: Analog-RoF (A-RoF), Phase Modulation (PM)-based Digital RoF (PM-A-RoF), and DSP-based Hybrid Digital-Analog RoF (DA-RoF). However, these solutions improve the signal-to-noise ratio at the expense of spectral efficiency and capacity.

[0003] To improve the capacity of RoF systems, a dual-biased quadrature amplitude modulation coherent detection system is typically used to increase the modulation dimension of DA-RoF. Although the modulation dimension of DA-RoF is increased, dynamic impairments such as phase noise and dynamic polarization rotation still exist.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a digital analog fronthaul system that addresses the technical problem that existing dual-biased orthogonal amplitude modulation coherent detection systems, while increasing the modulation dimension of DA-RoF, still suffer from dynamic impairments such as phase noise and dynamic polarization rotation.

[0006] To achieve the above objectives, the present invention provides a digital analog fronthaul system, which includes: a DSP transmitter, a DSP receiver, and a time-interleaved digital-analog wireless fronthaul architecture.

[0007] The DSP transmitter is used to quantize and modulate the wireless signal to be modulated when it receives the wireless signal to be modulated, so as to obtain the modulated digital symbols and analog symbols.

[0008] The time-interleaved digital-analog wireless fronthaul architecture is used to perform time-domain interleaving of the modulated digital symbols and analog symbols to obtain interleaved digital symbols and analog symbols, wherein digital symbols and analog symbols are placed alternately in the time-interleaved digital-analog wireless fronthaul architecture;

[0009] The DSP receiver is used to make a decision and recover the interleaved digital and analog symbols to obtain the wireless signal.

[0010] Optionally, the time-interleaved digital-analog wireless fronthaul architecture includes alternating combinations of multiple digital symbols and multiple combinations of analog symbols.

[0011] Optionally, when the time-interleaved analog-digital wireless fronthaul architecture is a high-order architecture, the high-order digital symbols and high-order analog symbols generated by separating the analog symbols of the previous order are placed alternately.

[0012] Optionally, the DSP transmitter is further configured to perform quantization on the wireless signal to be modulated to obtain modulated digital symbols, the process of which is as follows:

[0013] S Tx =Q ro (S Tx );

[0014] Among them, Q ro S is a quantization factor quantized using the rounding principle. Tx For the wireless signal to be modulated, D Tx The modulated digital symbol.

[0015] Optionally, the DSP transmitter is further configured to subtract the modulated wireless signal from the modulated digital symbol to obtain the modulated analog symbol, the process of which is as follows:

[0016] A Tx =S Tx -D Tx ;

[0017] Among them, S Tx For the wireless signal to be modulated, D Tx A is the modulated digital symbol. Tx The modulated analog symbol.

[0018] Optionally, the DSP receiver is further configured to perform symbol decision on the interleaved digital symbols to obtain the decided digital signal;

[0019] The DSP receiver is also used to perform damage compensation on the interleaved analog symbols to obtain a compensated analog signal.

[0020] Optionally, the DSP receiver is further configured to add the decided digital signal and the compensated analog signal to obtain the recovered wireless signal, the process of which is as follows:

[0021] S Rx =A Rx +D Rx ;

[0022] Among them, D RxA is the digital signal following the judgment. Rx For the compensated analog signal, S Rx This is the restored wireless signal.

[0023] Optionally, the time-interleaved analog-digital wireless fronthaul architecture is further configured to perform high-order separation on the previous-order analog symbols to obtain high-order digital symbols and high-order analog symbols, and to perform time-domain interleaving on the high-order digital symbols and the high-order analog symbols to obtain interleaved digital symbols and analog symbols.

[0024] Optionally, the DSP receiver is further configured to add the higher-order digital symbols and the higher-order analog symbols to obtain the recovered wireless signal, the process of which is as follows:

[0025] S Rx_N =A Rx +D Rx_1 +D Rx_2 +…+D Rx_N ;

[0026] Among them, D Rx_1 D is the digital signal after the first-order decision. Rx_2 D is the digital signal after the second-order decision. Rx_N Let A be the digital signal after the Nth-order decision. Rx For the compensated analog signal, S Rx_N This is the restored wireless signal.

[0027] Optionally, the DSP receiver and the DSP transmitter are implemented based on a coherent receiver, which includes a PIN detector and a photodetector with transimpedance amplification.

[0028] This invention proposes a digital-analog fronthaul system, comprising: a DSP transmitter, a DSP receiver, and a time-interleaved digital-analog wireless fronthaul architecture. The DSP transmitter, upon receiving a wireless signal to be modulated, performs quantization modulation on the signal to obtain modulated digital and analog symbols. The time-interleaved digital-analog wireless fronthaul architecture performs time-domain interleaving on the modulated digital and analog symbols to obtain interleaved digital and analog symbols, wherein the digital and analog symbols are alternately placed in the time-interleaved digital-analog wireless fronthaul architecture. The DSP receiver performs decision recovery on the interleaved digital and analog symbols to obtain the wireless signal. Because this invention uses a time-interleaved digital-analog wireless fronthaul architecture to alternately place digital and analog symbols for time-domain interleaving, the impairment estimated from the digital symbols can be directly used at the DSP receiver to compensate for impairment in the analog signal to obtain the wireless signal, thus achieving dynamic impairment compensation for the analog symbols. Attached Figure Description

[0029] Figure 1 This is a structural block diagram of the first embodiment of the digital analog fronthaul system of the present invention;

[0030] Figure 2 This is a schematic diagram of the architecture of the digital analog fronthaul system based on a coherent communication system in the first embodiment of the digital analog fronthaul system of the present invention.

[0031] Figure 3 This is a schematic diagram of the digital and analog symbol arrangement of a modified first-order time-interleaved digital-analog wireless fronthaul architecture in the second embodiment of the digital-analog fronthaul system of the present invention.

[0032] Figure 4 This is a schematic diagram of the digital and analog symbol arrangement of a modified high-order time-interleaved digital-analog wireless fronthaul architecture in the second embodiment of the digital-analog fronthaul system of the present invention.

[0033] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0034] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0035] This invention provides a digital analog fronthaul system, referring to... Figure 1 , Figure 1 This is a structural block diagram of the first embodiment of the digital analog fronthaul system of the present invention.

[0036] With the rapid development of fifth-generation (5G) mobile communication, mobile fronthaul networks can utilize Radio over Fiber (RoF) technology to transmit wireless signals from the baseband unit (BBU) to the remote radio unit (RRU), supporting multiple mobile users. Traditional fronthaul solutions include the following:

[0037] 1. Analog RoF (A-RoF) is used; however, analog signals are susceptible to inter-symbol interference and nonlinear distortion, which require compensation in digital signal processing (DSP). One approach is to use a nonlinear equalizer for nonlinear compensation. However, the signal-to-noise ratio (SNR) of A-RoF based on a nonlinear equalizer is limited to approximately 22-25 dB. It can only support a maximum of 64-QAM, which is lower than the 32 dB SNR requirement for supporting 1024-QAM specified in the latest 3GPP standard.

[0038] 2. The A-ROF (PM-A-RoF) scheme based on phase modulation (PM) improves the signal-to-noise ratio at the expense of spectral efficiency. For every halving of spectral efficiency, the signal-to-noise ratio increases by 6 dB.

[0039] 3. The DSP-based hybrid digital-analog RoF (DA-RoF) scheme achieves a signal-to-noise ratio gain of over 10 dB while sacrificing half of the spectral efficiency, surpassing the 6 dB gain of the PM-A-RoF scheme.

[0040] However, the above-mentioned schemes improve the signal-to-noise ratio at the expense of spectral efficiency and capacity. To further improve the capacity of RoF systems, a common approach is to use a dual-biased quadrature amplitude modulation (DQAM) coherent detection system to increase the modulation dimension of DA-RoF by four times. However, dynamic impairments such as phase noise and dynamic polarization rotation still exist in coherent communication systems. To mitigate this problem, there are currently two approaches: one is a pilot-based approach, which can estimate dynamic channel impairments. However, pilots increase the PAPR of the transmitted signal, making it more susceptible to channel noise. The second approach uses co-source homodyne coherent signaling, which, under the premise of phase matching, can perfectly eliminate the influence of phase noise. This approach requires an additional polarization controller to control the co-transmitting local oscillator for coherent reception, increasing the hardware complexity of the system.

[0041] Therefore, this invention proposes a digital analog fronthaul system that can perform dynamic damage tracking and compensation without increasing hardware complexity or using pilot signals, thereby realizing an ultra-high capacity RoF system to meet the fronthaul needs of the post-5G and 6G era.

[0042] In this embodiment, the digital-analog fronthaul system includes: a DSP transmitter, a DSP receiver, and a time-interleaved digital-analog wireless fronthaul architecture;

[0043] The DSP transmitter is used to quantize and modulate the wireless signal to be modulated when it receives the wireless signal to be modulated, so as to obtain the modulated digital symbols and analog symbols.

[0044] The time-interleaved digital-analog wireless fronthaul architecture is used to perform time-domain interleaving of the modulated digital symbols and analog symbols to obtain interleaved digital symbols and analog symbols, wherein digital symbols and analog symbols are placed alternately in the time-interleaved digital-analog wireless fronthaul architecture;

[0045] The DSP receiver is used to make a decision and recover the interleaved digital and analog symbols to obtain the wireless signal.

[0046] It should be noted that the DSP transmitter refers to the transmitting part of a Digital Signal Processing (DSP) system. In wireless communication, the main function of the DSP transmitter is to convert digital information into analog signals suitable for wireless transmission and perform necessary modulation, encoding, and filtering operations.

[0047] Understandably, a DSP receiver refers to the receiving section of a digital signal processing system. In wireless communication, the main function of a DSP receiver is to receive and process analog signals transmitted from the wireless channel, converting them into digital signals for subsequent processing and decoding.

[0048] It should be understood that the time-interleaved analog-digital wireless fronthaul architecture is a novel time-interleaved DA-RoF (TI-DA-RoF) architecture proposed in this embodiment. Based on the realization of a high-capacity fronthaul system, compared to existing solutions, it can estimate and compensate for dynamic impairments without pilot assistance or self-coherent architectures. In the time-interleaved analog-digital wireless fronthaul architecture, digital and analog symbols are alternately placed. The impairments estimated from the digital symbols can be directly used to compensate for analog signal impairments through the DSP receiver, thereby achieving dynamic impairment compensation for the analog portion.

[0049] It should be noted that the wireless signal to be modulated refers to the original signal before digital modulation. This original signal can be digital data, voice signals, or other types of information. Digital symbols are used in modulation to represent different signal states or waveforms of digital information. Analog symbols are discrete representations of analog signals used in modulation to transmit them. Because signals change continuously in analog communication, they need to be discretized into a series of discrete analog symbols for processing and transmission in digital systems.

[0050] In its implementation, when the DSP transmitter receives the wireless signal to be modulated, it performs quantization modulation on the signal to obtain modulated digital symbols and modulated analog symbols. Then, through the time-interleaved digital-analog wireless fronthaul architecture, the modulated digital and analog symbols are alternately interleaved in the time domain. This allows the system impairments to be estimated using the modulated digital symbols and applied to adjacent modulated analog symbols for impairment compensation in the analog portion. Finally, the DSP receiver performs decision recovery on the interleaved digital and analog symbols to obtain the wireless signal. This method of estimating impairments based on the digital portion and then directly compensating for the analog portion enables blind equalization of link impairments, provides some tracking capability for dynamic impairments, increases the practicality of the link system, and achieves high-fidelity transmission of wireless signals.

[0051] For ease of understanding, the explanation focuses on the hardware implementation process, but does not limit the scope of this solution. (References) Figure 2 , Figure 2 This is a schematic diagram of the architecture of a digital-analog fronthaul system based on a coherent communication system, as shown in the first embodiment of the digital-analog fronthaul system of the present invention. Figure 2 As shown, the lower part is the hardware foundation, including: a dual-biased IQ modulator, a coherent receiver, a laser, and a local oscillator laser; the dual-biased IQ modulator performs analog-to-digital conversion and digital-to-analog conversion during signal transmission. Here, a first-order time-interleaved analog-to-digital wireless fronthaul architecture is selected to modulate the wireless signal to be transmitted using TI-DA-RoF. The signal is received using a coherent receiver, and the impairments are compensated for by polarization rotation, frequency offset estimation, and carrier phase recovery through the transmitter's DSP and receiver's DSP. Then, the wireless signal is restored by demodulating the TI-DA-RoF signal. The specific modulation and demodulation processes in the fronthaul link are as follows: modulation is performed through an Nρ-QAM quantizer to obtain a digital signal amplified by α times and an analog signal amplified by β times. Then, the modulated digital symbols and modulated analog symbols are alternately placed in the time-interleaved analog-to-digital wireless fronthaul architecture to perform time-domain interleaving. Thus, the system impairments can be estimated using the modulated digital symbols and applied to adjacent modulated analog symbols to compensate for the impairments in the analog part. Finally, the digital symbols are subjected to symbol determination, and then restored by 1 / α and 1 / β times to obtain the wireless signal.

[0052] In the time-interleaved analog-digital fronthaul architecture proposed above, high-fidelity wireless signal transmission can be achieved. In a channel with an actual signal-to-noise ratio of 21 dB, an equivalent signal-to-noise ratio exceeding 32 dB can be achieved, meeting the transmission requirements of 1024-QAM. Compared to existing pilot-assisted and zero-difference self-coherent schemes, this embodiment can achieve carrier recovery based on blind phase search of digital signals. Compared to pilot-assisted schemes, this scheme simplifies the DSP process at the transmitter and avoids the increase in peak-to-average power ratio caused by pilot insertion. A larger peak-to-average power ratio increases quantization noise during DAC conversion. Compared to zero-difference self-coherent schemes, this scheme does not require additional fiber optic links (for transmitting co-source local oscillators, LOs) and additional polarization controllers (for controlling the polarization direction of the LOs), thus reducing hardware complexity and power consumption.

[0053] In this embodiment, when the DSP transmitter receives the wireless signal to be modulated, it quantizes and modulates the signal to obtain modulated digital symbols and modulated analog symbols. Then, through a time-interleaved analog-digital fronthaul architecture, the modulated digital and analog symbols are alternately placed and interleaved in the time domain. This allows the system impairment to be estimated using the modulated digital symbols and applied to adjacent modulated analog symbols for impairment compensation in the analog portion. Finally, the DSP receiver performs decision recovery on the interleaved digital and analog symbols to obtain the wireless signal. Because this invention uses a time-interleaved analog-digital fronthaul architecture to alternately place digital and analog symbols for time domain interleaving, impairment estimation based on the digital portion is directly applied to compensate for the analog portion. This enables blind equalization of link impairments and achieves dynamic impairment compensation for analog symbols.

[0054] Based on the first embodiment described above, a second embodiment of the digital analog fronthaul system of the present invention is proposed.

[0055] In this embodiment, the DSP transmitter is also used to perform quantization operations on the wireless signal to be modulated to obtain modulated digital symbols. The process is as follows:

[0056] D Tx =Q ro (S Tx );

[0057] Among them, Q ro S is a quantization factor quantized using the rounding principle. Tx For the wireless signal to be modulated, D Tx The modulated digital symbol.

[0058] In a specific implementation, at the DSP transmitter, the wireless signal S to be modulated is... Tx By performing quantization, a precisely magnified digital symbol D can be obtained. Tx .

[0059] Furthermore, in this embodiment, the DSP transmitter is also used to obtain a modulated analog symbol by subtracting the wireless signal to be modulated from the modulated digital symbol, the process of which is as follows:

[0060] A Tx =S Tx -D Tx ;

[0061] Among them, S Tx For the wireless signal to be modulated, D Tx A is the modulated digital symbol. Tx The modulated analog symbol.

[0062] In the specific implementation, the quantization noise is then obtained by subtracting the wireless signal to be modulated from the quantized digital symbol, thus obtaining the precise modulated analog symbol A. Tx .

[0063] Furthermore, in this embodiment, the DSP receiver is also used to perform symbol decision on the interleaved digital symbols to obtain the decided digital signal;

[0064] The DSP receiver is also used to perform damage compensation on the interleaved analog symbols to obtain a compensated analog signal.

[0065] Furthermore, in this embodiment, the DSP receiver is also used to add the decided digital signal and the compensated analog signal to obtain the recovered wireless signal. The process is as follows:

[0066] S Rx =A Rx +D Rx ;

[0067] Among them, D Rx A is the digital signal following the judgment. Rx For the compensated analog signal, S Rx This is the restored wireless signal.

[0068] In the specific implementation, at the DSP receiver, the digital signal D after the decision is processed. Rx and the analog signal A after damage compensation Rx The summation restores the wireless signal.

[0069] Furthermore, considering the architecture of multiple symbol combinations, this embodiment proposes a modified time-interleaved digital-analog wireless fronthaul architecture that combines N digital and N analog symbols in the time domain. For example... Figure 3 As shown, Figure 3 This is a schematic diagram illustrating the arrangement of digital and analog symbols in a modified first-order time-interleaved analog-digital wireless fronthaul architecture according to a second embodiment of the digital-analog fronthaul system of the present invention. The time-interleaved analog-digital wireless fronthaul architecture in this embodiment includes alternating placement of multiple combinations of digital symbols and multiple combinations of analog symbols.

[0070] It should be noted that in the field of communications, an OFDM Symbol (and CP) is a time unit for transmitting data in OFDM multicarrier modulation technology. It consists of multiple subcarriers and achieves efficient spectrum utilization and anti-interference capability through orthogonal modulation.

[0071] Furthermore, considering higher-order architectures, this embodiment proposes a modified higher-order time-interleaved analog-digital wireless fronthaul architecture. This involves further dividing the analog portion generated by the first-order architecture into digital and analog symbols, followed by time-domain interleaving; then, the analog portion generated by the second-order architecture is again divided into digital and analog symbols, followed by time-domain interleaving, and so on. Figure 4 As shown, Figure 4 This is a schematic diagram of the digital and analog symbol arrangement of a modified high-order time-interleaved analog-digital wireless fronthaul architecture in the second embodiment of the digital-analog fronthaul system of the present invention. In this embodiment, when the time-interleaved analog-digital wireless fronthaul architecture is a high-order architecture, the high-order digital symbols and high-order analog symbols generated by separating the analog symbols of the previous order are placed alternately.

[0072] It should be noted that the different arrangements of digital and analog symbols will affect the results of subsequent digital signal processing. An arrangement of one digital and one analog symbol is more conducive to channel impairment estimation and compensation, and the impairment compensation for the analog part will be more accurate. Since channel impairment estimation is based on the digital part, the analog part cannot be estimated for impairment. Furthermore, due to the slow-varying characteristics of system impairments, such as polarization state rotation and phase noise, when the impairment changes in adjacent symbols are not significant, the impairment estimation of the digital part can be used to compensate for adjacent analog signals.

[0073] In high-order time-interleaved analog-digital wireless fronthaul architectures, the larger the proportion of the digital component, the stronger the system's robustness. This is because the digital component can make decisions, which is a prerequisite for using digital signal processing algorithms. A larger proportion of the digital component is also more conducive to estimating and compensating for channel impairments. Thus, by estimating impairments based on the digital component and directly compensating for the analog component, blind equalization of link impairments can be achieved. Therefore, it can track dynamic impairments to some extent, increasing the practicality of the link system and enabling high-fidelity transmission of wireless signals.

[0074] Furthermore, the time-interleaved analog-digital wireless fronthaul architecture described in this embodiment is also used to perform high-order separation on the previous-order analog symbols to obtain high-order digital symbols and high-order analog symbols, and to perform time-domain interleaving on the high-order digital symbols and the high-order analog symbols to obtain interleaved digital symbols and analog symbols.

[0075] It should be noted that by extending the time-interleaved analog-to-digital wireless fronthaul architecture proposed in this embodiment to a higher-order time-interleaved analog-to-digital wireless fronthaul architecture, the analog signal generated by the first-order digital-to-analog conversion is separated into digital and analog components again using the first-order method. This allows for further analog-to-digital decomposition of the analog signal. A larger proportion of the digital component is more beneficial for estimating and compensating for channel impairments.

[0076] Furthermore, in this embodiment, the DSP receiver is also used to add the higher-order digital symbols and the higher-order analog symbols to obtain the recovered wireless signal. The process is as follows:

[0077] S Rx_N =A Rx +D Rx_1 +D Rx_2 +…+D Rx_N ;

[0078] Among them, D Rx_1 D is the digital signal after the first-order decision. Rx_2 D is the digital signal after the second-order decision. Rx_N Let A be the digital signal after the Nth-order decision. Rx For the compensated analog signal, S Rx_N This is the restored wireless signal.

[0079] In practical implementation, the analog signal generated by the first-order digital-to-analog converter is further separated into digital and analog components using the same first-order method. This allows for a second analog-to-digital decomposition of the analog signal, yielding higher-order digital and analog signals. A larger proportion of the digital component is more beneficial for estimating and compensating for channel impairments.

[0080] Furthermore, in this embodiment, the DSP receiver and the DSP transmitter are implemented based on a coherent receiver, which includes a PIN detector and a photodetector with transimpedance amplification.

[0081] This embodiment considers higher-order architectures and proposes a modified higher-order time-interleaved analog-digital wireless fronthaul architecture. This involves further dividing the analog portion generated by the first-order architecture into digital and analog symbols, followed by time-domain interleaving; then, the analog portion generated by the second-order architecture is again divided into digital and analog symbols, and time-domain interleaving is performed, and so on. The larger the proportion of the digital portion, the stronger the system's robustness. This is because the digital portion allows for decision-making, which is a prerequisite for using digital signal processing algorithms. A larger proportion of the digital portion is also more conducive to estimating and compensating for channel impairments. By estimating impairments based on the digital portion and then directly compensating for the analog portion, blind equalization of link impairments can be achieved. Therefore, it provides some tracking capability for dynamic impairments, increases the practicality of the link system, and enables high-fidelity transmission of wireless signals.

[0082] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0083] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0084] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory / random access memory, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0085] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A digital-analog fronthaul system, characterized in that, The digital-analog fronthaul system includes: a DSP transmitter, a DSP receiver, and a time-interleaved digital-analog wireless fronthaul architecture; The DSP transmitter is used to quantize and modulate the wireless signal to be modulated when it receives the wireless signal to be modulated, so as to obtain the modulated digital symbols and analog symbols. The time-interleaved digital-analog wireless fronthaul architecture is used to perform time-domain interleaving of the modulated digital symbols and analog symbols to obtain interleaved digital symbols and analog symbols; wherein, in the time-interleaved digital-analog wireless fronthaul architecture, digital symbols and analog symbols are placed alternately in the time domain as a single symbol or multiple symbols, so that the impairment estimated from the digital symbols is used to compensate for the impairment of adjacent analog symbols. The DSP receiver is used to make a decision and recover the interleaved digital and analog symbols to obtain the wireless signal.

2. The digital-analog fronthaul system as described in claim 1, characterized in that, When the time-interleaved analog-digital wireless fronthaul architecture is a high-order architecture, the high-order digital symbols and high-order analog symbols generated by separating the analog symbols of the previous order are placed alternately.

3. The digital-analog fronthaul system as described in claim 1, characterized in that, The DSP transmitter is also used to perform quantization operations on the wireless signal to be modulated to obtain modulated digital symbols. The process is as follows: ； in, The quantization factor is determined using the rounding principle. For the wireless signal to be modulated, The modulated digital symbol.

4. The digital-analog fronthaul system as described in claim 3, characterized in that, The DSP transmitter is also used to obtain a modulated analog symbol by subtracting the modulated wireless signal from the modulated digital symbol, the process of which is as follows: ； in, For the wireless signal to be modulated, The modulated digital symbols, The modulated analog symbol.

5. The digital-analog fronthaul system as described in claim 4, characterized in that, The DSP receiver is also used to perform symbol decision on the interleaved digital symbols to obtain the decided digital signal; The DSP receiver is also used to perform damage compensation on the interleaved analog symbols to obtain a compensated analog signal.

6. The digital-analog fronthaul system as described in claim 5, characterized in that, The DSP receiver is also used to add the decided digital signal and the compensated analog signal to obtain the recovered wireless signal, the process of which is as follows: ； in, The digital signal following the judgment. The compensated analog signal, This is the restored wireless signal.

7. The digital-analog fronthaul system as described in claim 2, characterized in that, The time-interleaved analog-digital wireless fronthaul architecture is further used to perform high-order separation on the previous-order analog symbols to obtain high-order digital symbols and high-order analog symbols, and to perform time-domain interleaving on the high-order digital symbols and the high-order analog symbols to obtain interleaved digital symbols and analog symbols.

8. The digital-analog fronthaul system as described in claim 7, characterized in that, The DSP receiver is also used to add the higher-order digital symbols and the higher-order analog symbols to obtain the recovered wireless signal. The process is as follows: ； in, The digital signal after the first-order decision. This is the digital signal after the second-order decision. The digital signal after the Nth-order decision. The compensated analog signal, This is the restored wireless signal.

9. The digital-analog fronthaul system as described in any one of claims 1-8, characterized in that, The DSP receiver and the DSP transmitter are implemented based on a coherent receiver, which includes a PIN detector and a photodetector with transimpedance amplification.

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