4g / 5g signal home coverage system based on rof analog optical transmission and pon network

Abstract

The embodiment of the present specification provides a 4G / 5G signal household coverage system based on ROF analog optical transmission and PON network, comprising: a ROF analog optical transmission subsystem, a passive optical network (PON) broadband access subsystem and a plurality of first multiplexers / demultiplexers; the PON broadband access subsystem comprises an OLT device, a plurality of ODN networks and a plurality of ONU devices, the OLT device comprises a plurality of OLT optical ports, each OLT optical port corresponds to each ODN network one by one; the ROF analog optical subsystem comprises a base station and a plurality of user terminals (UE), the base station comprises a 4G / 5G dual-mode BBU unit, an expansion unit (EU) and a plurality of remote units which are sequentially optically connected; the expansion unit (EU) comprises a first ROF module, the first ROF module comprises a plurality of ROF optical ports, each ROF optical port and each OLT optical port are simultaneously optically connected to a first multiplexer / demultiplexer. The system effectively improves the system utilization, reduces the network upgrade and maintenance cost.

Description

Technical Field

[0001] This manual relates to the field of wireless communication and optical access network convergence, and in particular to a 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network. It is especially suitable for large-scale coverage of buildings, communities, and homes, FTTR+5G convergence, and parallel coverage scenarios in multiple areas. Background Technology

[0002] Currently, indoor mobile communication coverage mainly relies on traditional indoor distribution systems, digital fiber optic repeaters, and Radio over Fire (RoF) systems. However, these solutions all have varying degrees of shortcomings in actual deployment and operation. First, traditional indoor distribution systems require separate RF feeders or cables, which are complex and time-consuming to construct. Furthermore, due to the large number of passive components and connectors involved, the retrofit cost is high, making it difficult to adapt to rapidly changing indoor environments. Second, while digital fiber optic repeaters offer high bandwidth transmission capabilities, their equipment costs are high, power consumption is high, and they introduce significant signal processing latency, making them less suitable for low-latency services (such as 5G uRLLC scenarios). Third, existing RoF systems are mostly single-output architectures with limited coverage capacity, unable to meet the dense deployment needs of large buildings, stadiums, and other multi-user, high-traffic environments. Additionally, external wavelength division multiplexing (WDM) demultiplexers are typically required at the entry point, increasing the number of network nodes, introducing additional insertion loss, and raising the probability of failure. Furthermore, most existing equipment only supports single-mode (e.g., only 4G or only 5G), making it impossible to simultaneously cover both 4G and 5G signals using the same equipment, resulting in redundant construction during network upgrades. Finally, current indoor mobile communication coverage solutions are difficult to seamlessly reuse with the widely deployed Passive Optical Network (PON) systems of operators, failing to fully utilize existing fiber optic infrastructure, leading to resource waste and low deployment efficiency.

[0003] Therefore, it is desirable to provide a 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network, which can cover multiple independent areas or buildings through a single system, support 4G and 5G dual-mode integrated coverage, and be compatible with existing networks and newly built networks at the same time, effectively improving system utilization and reducing network upgrade and maintenance costs. Summary of the Invention

[0004] This specification provides one or more embodiments of a 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network, including: an ROF analog optical subsystem, a PON broadband access subsystem, and multiple first multiplexers / demultiplexers; the PON broadband access subsystem includes an optical line terminal (OLT) device, a multi-channel passive optical distribution (ODN) network, and multiple optical network unit (ONU) devices, the OLT device includes multiple OLT optical ports, each OLT optical port corresponds one-to-one with one of the passive optical distribution (ODN) networks, and each OLT optical port is optically connected to one of the first multiplexers / demultiplexers; The ROF analog photonic system includes a base station and multiple user terminals (UEs). The base station includes a 4G / 5G dual-mode BBU unit, an extension unit (EU), and multiple remote units connected in sequence optically. Each extension unit (EU) includes a first ROF module with multiple ROF optical ports, and each ROF optical port and an OLT optical port are simultaneously optically connected to a first multiplexer / demultiplexer. Each remote unit includes a second multiplexer / demultiplexer module and a second ROF module, wherein: In the downlink direction, the 4G / 5G dual-mode BBU unit transmits the obtained dual-mode baseband digital signal to the extended unit EU. After obtaining multiple downlink dual-mode radio frequency signals, it sends them to the first ROF module to convert the downlink dual-mode radio frequency signals into multiple first downlink optical signals with the same first wavelength. These signals are then output in parallel through the multiple ROF optical ports. After being combined with the second downlink optical signals with the second wavelengths output in parallel through the multiple OLT optical ports, they are multiplexed through multiple first multiplexers and demultiplexers. Finally, they are multiplexed through multiple passive optical distribution network (ODN) networks and transmitted sequentially to multiple remote units and multiple user terminals (UEs). In the uplink direction, for any of the remote units, after the uplink dual-mode radio frequency signal transmitted by the user terminal UE is converted by the second ROF module, it is combined with the second uplink optical signal of the fourth wavelength of the optical network unit ONU device through the second multiplexing and demultiplexing module, and then multiplexed through the passive optical distribution network (ODN) to be transmitted to the first multiplexer and demultiplexer for demultiplexing. Finally, it is sent by the first ROF module to the 4G / 5G dual-mode BBU unit.

[0005] In some embodiments, the expansion unit EU further includes: a standard digital optical port, a digital-to-analog converter module, and an RF power distribution module; the standard digital optical port is used to transmit the dual-mode baseband digital signal of the 4G / 5G dual-mode BBU unit to the expansion unit EU; the digital-to-analog converter module is used to convert the dual-mode baseband digital signal into the downlink dual-mode RF signal and then send it to the RF power distribution module; the RF power distribution module is used to divide the downlink dual-mode RF signal into multiple dual-mode baseband RF signals and then send them to the first ROF module.

[0006] In some embodiments, the standard digital optical port includes one of eCPRI, CPRI, and ORAN standard digital optical ports.

[0007] In some embodiments, the multi-path passive optical distribution ODN network includes a beam splitter, and the plurality of remote units are optically connected to the extension unit EU through the beam splitter.

[0008] In some embodiments, the beam splitter is a beam splitter capable of satisfying at least one of the beam splitting ratios of 1:8, 1:32, and 1:64.

[0009] In some embodiments, each of the remote units further includes a 4G / 5G broadband linear amplification module and a wireless interface; the wireless interface is used to realize wireless communication between the remote unit and the user terminal UE; the 4G / 5G broadband linear amplification module is used to amplify the downlink dual-mode radio frequency signal generated by the second ROF module after photoelectric conversion and then transmit it to the wireless interface.

[0010] In some embodiments, both the first multiplexing / splitting module and the second multiplexing / splitting module are multiplexing / splitting modules employing WDM wavelength division multiplexing technology.

[0011] In some embodiments, the number of the plurality of ROF optical ports is less than or equal to 8.

[0012] In some embodiments, the first wavelength, the second wavelength, the third wavelength, and the fourth wavelength are all different, and the third wavelength is a tunable wavelength of 1410nm ± 0.2nm.

[0013] In some embodiments, for the first downlink optical signal output from each of the ROF optical ports: The first downlink optical signal and a second downlink optical signal of the second wavelength output from the OLT optical port are combined by a corresponding first multiplexer / demultiplexer to generate a third downlink optical signal. This third downlink optical signal is then multiplexed through a corresponding passive optical distribution network (ODN) and transmitted to a remote unit. After being demultiplexed by the second multiplexing / demultiplexing module of the remote unit, the signal is transmitted to the connected optical network unit (ONU) and the second ROF module. The second ROF module then converts the first downlink optical signal obtained after demultiplexing into a downlink dual-mode radio frequency signal and sends it to the user terminal (UE).

[0014] The present invention has the following beneficial effects: 1. The first ROF module of the expansion unit EU of this system includes multiple ROF optical ports. The multiple ROF optical ports adopt multi-channel ROF parallel output. This system can cover multiple independent coverage areas or buildings, and the coverage capability is increased to many times that of the existing single-channel output solution, which is suitable for large-scale deployment scenarios.

[0015] 2. This system is equipped with a 4G / 5G dual-mode BBU unit, which supports integrated coverage of 4G and 5G dual modes. One system can be compatible with existing networks (such as 4G networks) and newly built networks (such as 5G networks) at the same time, effectively improving equipment utilization and reducing network upgrade and maintenance costs.

[0016] 3. The baseband signal of this system is converted into a radio frequency signal in real time in the extension unit EU. After being processed by the first ROF module, it is transmitted in ROF analog light. The end-to-end delay can be controlled within 300 nanoseconds, and the system has excellent real-time performance.

[0017] 4. Each remote unit of this system has a built-in second multiplexing / splitting module based on WDM wavelength division multiplexing technology, which enables direct single-fiber access and plug-and-play functionality, reducing external optical nodes and connection failure points, and improving the reliability of this system.

[0018] 5. This system can fully reuse the operator's existing PON network infrastructure without the need to lay new fiber optic cables or modify existing lines, which can greatly reduce construction and deployment costs.

[0019] 6. In the uplink direction, the first uplink optical signal of this system adopts a tunable wavelength of 1410nm±0.2nm, which supports multiple users accessing at the same time without wavelength conflict and is suitable for large-scale point-to-multipoint coverage scenarios.

[0020] 7. The remote unit of this system is lightweight, low power consumption and configuration-free, and can be directly deployed in user-side environments such as homes and corridors, making installation convenient.

[0021] 8. The entire system is under the unified management of the operator, ensuring that signal quality, transmission delay, synchronization accuracy and anti-interference performance are manageable and controllable. Attached Figure Description

[0022] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein: Figure 1 This is a schematic diagram of a 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network, as shown in some embodiments of this specification. Figure 2 This is a block diagram illustrating the overall architecture of a ROF-simulated photonic system based on some embodiments shown in this specification. Figure 3 This is a block diagram illustrating the signal processing and output principle of an expansion unit EU using 8 ROF optical ports, as shown in some embodiments of this specification. Figure 4 This is a flowchart illustrating the downlink and uplink workflow of the remote unit according to some embodiments of this specification.

[0023] Labeling Explanation: 110, 4G / 5G Dual-Mode BBU Unit; 120, Extended Unit (EU); 120-1, First ROF Module; 130, Optical Line Terminal (OLT) Equipment; 140, First Multiplexer / Demultiplexer; 150, Passive Optical Distribution Network (ODN); 160, Remote Unit; 170, Optical Network Unit (ONU) Equipment; 180, User Terminal (UE). Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] Figure 1 This is a schematic diagram of a 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network, as shown in some embodiments of this specification. Figure 2 This is a block diagram illustrating the overall architecture of a ROF-simulated photonic system based on some embodiments of this specification. Figure 3 This is a block diagram illustrating the signal processing and output principle of an expansion unit EU using 8 ROF optical ports, as shown in some embodiments of this specification. Figure 4This is a flowchart illustrating the downlink and uplink workflow of the remote unit according to some embodiments of this specification.

[0026] In some embodiments, such as Figure 1 As shown, the 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network (hereinafter referred to as the system) includes an ROF (Radio over Fiber) analog optical transmission subsystem, a passive optical network (PON) broadband access subsystem, and multiple first multiplexers / splitters 140.

[0027] In some embodiments, the PON broadband access subsystem includes an optical line terminal (OLT) device 130, a multi-channel passive optical distribution network (ODN) 150, and multiple optical network units (ONU) devices 170. The OLT device includes multiple OLT optical ports, and each OLT optical port corresponds one-to-one with one passive optical distribution network (ODN).

[0028] In some embodiments, the ROF analog photonic system includes a base station and multiple user equipment (UE) units 180. The base station includes a 4G / 5G dual-mode BBU (Baseband Unit) unit 110, an extension unit (EU) 120, and multiple remote units 160, which are optically connected in sequence. The extension unit EU 120 includes a first ROF module 120-1, which includes multiple ROF optical ports. Each ROF optical port and an OLT optical port are optically connected to a first multiplexer / demultiplexer. Each remote unit includes a second multiplexer / demultiplexer module and a second ROF module, wherein: In the downlink direction, the 4G / 5G dual-mode BBU unit 110 transmits the obtained dual-mode baseband digital signal to the extension unit EU 120. After digital-to-analog conversion and RF power division, multiple downlink dual-mode RF signals are obtained and sent to the first ROF module 120-1. The first ROF module 120-1 converts the multiple downlink dual-mode RF signals into multiple first downlink optical signals with the same first wavelength. After being output in parallel through multiple ROF optical ports, each first downlink optical signal is output through one ROF optical port. For each first downlink optical signal output by the ROF optical port: The first downlink optical signal and the second downlink optical signal of the second wavelength output from one OLT optical port are combined by a corresponding first multiplexer / demultiplexer 140 to generate a third downlink optical signal. This third downlink optical signal is then multiplexed by a corresponding passive optical distribution network (ODN) and transmitted to a remote unit. After being demultiplexed by the second multiplexer / demultiplexer module of the remote unit, the signal is transmitted to the connected optical network unit (ONU) and the second ROF module. The second ROF module then converts the first downlink optical signal obtained after demultiplexing into a downlink dual-mode radio frequency signal and sends it to the user terminal (UE). In the uplink direction, for any remote unit, the uplink dual-mode radio frequency signal transmitted by the user terminal UE is converted into a first uplink optical signal with a third wavelength by the second ROF module. This signal is then combined with the second uplink optical signal with a fourth wavelength from the optical network unit (ONU) by the second multiplexing / demultiplexing module to generate a third uplink optical signal. This third uplink optical signal is then multiplexed through the passive optical distribution network (ODN) and transmitted to the first multiplexer / demultiplexer. After being demultiplexed by the first multiplexer / demultiplexer, the signal is transmitted to the first ROF module and the OLT device, respectively. The first ROF module then converts the first uplink optical signal obtained after demultiplexing into an uplink dual-mode radio frequency signal and sends it to the 4G / 5G dual-mode BBU unit.

[0029] The 4G / 5G dual-mode BBU unit can be used to perform baseband processing on 4G / 5G user data (such as voice, video, web pages, etc.) within the base station, obtaining dual-mode baseband digital signals, and then performing resource scheduling and data interaction. Baseband processing refers to encapsulating user data into 4G and 5G dual-mode baseband digital signals that conform to 4G / 5G standards. Dual-mode baseband digital signals are digital signals that can carry both 4G and 5G information. Resource scheduling refers to dynamically allocating time, frequency, power, etc., for the 4G and 5G dual-mode baseband digital signals. For example, resource scheduling includes allocating the time for transmitting 4G and 5G baseband digital signals.

[0030] The user terminal (UE) can be used to transmit 4G and 5G radio frequency signals.

[0031] In some embodiments, the number of ROF optical ports on the first ROF module is equal to the number of OLT optical ports on the optical line terminal (OLT) device. For example, the number of ROF optical ports and the number of OLT optical ports can both be one of 2, 4, 6, 8, etc.

[0032] In some embodiments, the number of multiple ROF optical ports is less than or equal to 8. The first ROF module is allowed to output a maximum of 8 first downlink optical signals in parallel.

[0033] In some embodiments, the first, second, third, and fourth wavelengths are all different. For example, the first and second wavelengths in the downlink direction can be 1370nm and 1490nm respectively, the third wavelength in the uplink direction can be 1410nm, and the fourth wavelength can be 1310nm. This allows the ROF analog optical system and the PON broadband access subsystem to use the same passive optical distribution ODN network for optical signal transmission across different wavelength ranges, ensuring no crosstalk or interference between the optical signals of the ROF analog optical system and the PON broadband access subsystem.

[0034] In some embodiments, the third wavelength can also be a tunable wavelength of 1410nm ± 0.2nm. By using a tunable wavelength of 1410nm ± 0.2nm for the first uplink optical signal, wavelength conflict-free access for multiple users simultaneously is supported, making it suitable for large-scale point-to-multipoint coverage scenarios. In this case, multiple ROF optical ports use a fixed wavelength of 1370nm in the downlink direction; and the first uplink optical signal uses a tunable wavelength of 1410nm ± 0.2nm in the uplink direction. This ensures complete wavelength isolation between the optical signals transmitted on the ROF analog optical system and the PON broadband access subsystem, enabling shared fiber transmission of optical signals between the PON broadband access subsystem and the ROF analog optical system via WDM. Furthermore, the system employs a unified synchronization method to ensure time delay consistency among multiple remote units. In some embodiments, the extension unit EU further includes: a standard digital optical port, a digital-to-analog converter module, and an RF power distribution module; the standard digital optical port is used to transmit the dual-mode baseband digital signal of the 4G / 5G dual-mode BBU unit to the extension unit EU; the digital-to-analog converter module is used to convert the dual-mode baseband digital signal into a downlink dual-mode RF signal and then send it to the RF power distribution module; the RF power distribution module is used to divide the downlink dual-mode RF signal into multiple dual-mode baseband RF signals and then send them to the first ROF module.

[0035] In some embodiments, the standard digital optical port includes one of the following: eCPRI (enhanced Common Public Radio Interface), CPRI (Common Public Radio Interface), and ORAN (Open Radio Access Network) standard digital optical ports.

[0036] In some embodiments, the multi-path passive optical distribution ODN network includes a splitter, and multiple remote units are optically connected to the extension unit EU120 via the splitter. In some embodiments, each passive optical distribution ODN network also includes one optical fiber, and multiple optical fibers are optically connected to the splitter.

[0037] In some embodiments, the beam splitter is capable of satisfying at least one beam splitting ratio among 1:8, 1:32, and 1:64. In some embodiments, the beam splitter is preferably a beam splitter with a 1:8 beam splitting ratio. The beam splitter configuration enables the system to meet single-port multi-user coverage requirements.

[0038] In some embodiments, each remote unit further includes a 4G / 5G broadband linear amplifier module and a wireless interface. The wireless interface is used to enable wireless communication between the remote unit and the user terminal (UE). The 4G / 5G broadband linear amplifier module amplifies the downlink dual-mode radio frequency signal generated by the second ROF module after photoelectric conversion and then transmits it to the wireless interface.

[0039] In some embodiments, both the first and second multiplexing / splitting modules employ WDM (Wavelength Division Multiplexing) technology. The remote unit uses a single-fiber-to-the-home (SIP) access method and integrates a second multiplexing / splitting module using WDM technology. In the downlink direction, the remote unit directly separates a first downlink optical signal with a wavelength of 1370nm through the second multiplexing / splitting module. This first downlink optical signal undergoes photoelectric conversion by the second ROF module within the remote unit, generating a downlink dual-mode RF signal. This signal is then amplified by a 4G / 5G broadband linear amplifier module before being output to the wireless interface. In the uplink direction, the remote unit uses a 1410nm±0.2nm tunable optical transmitter module. Each remote unit has a unique wavelength offset to avoid interference from multiple users. The entire remote unit employs a low-power design and requires no complex configuration. Each remote unit in this system uses a built-in second multiplexing / splitting module based on WDM wavelength division multiplexing technology to achieve direct single-fiber access and plug-and-play functionality, reducing external optical nodes and connection failure points and improving the reliability of the system.

[0040] like Figure 2 As shown, considering specific application scenarios (e.g., tunable wavelengths of 1370nm, 1490nm, and 1410nm ± 0.2nm for the first, second, and third wavelengths respectively), the working principle of the ROF simulated photonic system is as follows: In the downlink direction, the 4G / 5G dual-mode BBU unit transmits the obtained dual-mode baseband digital signal to the standard digital optical interface. After baseband signal processing by the extension unit EU, multiple downlink dual-mode RF signals are obtained and sent to the first ROF module for ROF processing. The first ROF module converts the multiple downlink dual-mode RF signals into eight first downlink optical signals with a wavelength of 1370nm each. These signals are then output in parallel through eight ROF optical ports. For each first downlink optical signal output from an ROF optical port: the first downlink optical signal is combined with a second downlink optical signal with a wavelength of 1490nm output from one OLT optical port of the optical line terminal (OLT) device. After WDM multiplexing and demultiplexing by a corresponding first multiplexer / demultiplexer based on WDM technology, a third downlink optical signal is generated. This third downlink optical signal is then multiplexed through a corresponding passive optical distribution network (ODN) and transmitted to a remote unit. After demultiplexing by the second multiplexer / demultiplexer module of the remote unit, the signals are transmitted to the connected optical network unit (ONU) device and the second ROF module. The module converts the first downlink optical signal obtained after wavelength division into a downlink dual-mode radio frequency signal and sends it to the user terminal UE. In the uplink direction, for any remote unit, the uplink dual-mode radio frequency signal transmitted by the user terminal UE is converted into a first uplink optical signal with a tunable wavelength of 1410nm±0.2nm by the second ROF module. This first uplink optical signal is then combined with the second uplink optical signal with a wavelength of 1310nm by the optical network unit (ONU) by the second multiplexing / demultiplexing module to generate a third uplink optical signal. This third uplink optical signal is then multiplexed through the passive optical distribution network (ODN) and transmitted to the first multiplexer / demultiplexer. After being demultiplexed by the first multiplexer / demultiplexer, the signal is transmitted to the first ROF module and the OLT device, respectively. The first ROF module converts the first uplink optical signal obtained after demultiplexing into an uplink dual-mode baseband digital signal and sends it to the 4G / 5G dual-mode BBU unit.

[0041] like Figure 3 As shown, considering specific application scenarios (e.g., using an 8-channel ROF optical port expansion unit EU), the working principle of signal processing and output of the expansion unit EU is as follows: In the downlink direction, the extension unit (EU) interfaces with the 4G / 5G dual-mode BBU unit via a standard digital optical port. After receiving the dual-mode baseband digital signal from the 4G / 5G dual-mode BBU unit, the EU sequentially performs digital demodulation and baseband processing, 4G / 5G dual-mode up-conversion, RF power division into eight dual-mode RF signals, and eight ROF optical modulations to obtain eight first downlink optical signals with a wavelength of 1370nm. These first downlink optical signals are then output in parallel through the eight ROF optical ports. Digital demodulation refers to recovering the original digital baseband IQ data from the CPRI or eCPRI data stream, while simultaneously extracting the timing and frame synchronization information of the digital baseband IQ data. The CPRI or eCPRI data stream is the data stream obtained after the dual-mode baseband digital signal passes through the standard digital optical port. Baseband processing can involve signal format conversion, filtering, or gain adjustment of the digital baseband IQ data. 4G / 5G dual-mode upconversion can convert the processed dual-mode baseband digital signal into a dual-mode baseband RF signal. RF power distribution to eight dual-mode RF signals can be performed in the RF power distribution module of the 4G / 5G dual-mode BBU unit, dividing the dual-mode baseband RF signal into eight equally distributed dual-mode baseband RF signals with the same frequency and phase. Eight-channel ROF optical modulation can be achieved through the first ROF module, loading the eight dual-mode baseband RF signals onto eight optical waves, each transmitting a first downlink optical signal with a wavelength of 1370nm.

[0042] like Figure 4 As shown, considering specific application scenarios (e.g., the remote unit includes a built-in second multiplexing / splitting module based on WDM wavelength division multiplexing technology), the working principle of a remote unit in the downlink and uplink directions is as follows: In the downlink direction of the remote unit, after receiving a single fiber-to-the-home signal, the signal is split by the built-in second multiplexing / demultiplexing module based on WDM wavelength division multiplexing technology to obtain a first downlink optical signal with a wavelength of 1370nm. This signal is then transmitted to the second ROF module for ROF photoelectric conversion to obtain a downlink dual-mode radio frequency signal. After being amplified by the 4G / 5G broadband linear amplification module in the remote unit, the signal is transmitted to the wireless interface on the remote unit to radiate the amplified 4G / 5G downlink dual-mode radio frequency signal for the user terminal UE to receive. In the uplink direction of the remote unit, after receiving the uplink dual-mode RF signal transmitted by the user terminal UE through the wireless interface, the remote unit amplifies the uplink dual-mode RF signal through RF LAN and transmits it to the second ROF module for ROF photoelectric conversion to obtain a first uplink photoelectric signal with a tunable wavelength of 1410±0.2nm. Then, it sends the second uplink optical signal with a wavelength of 1310nm from the optical network unit ONU device through the built-in second multiplexing and demultiplexing module based on WDM wavelength division multiplexing technology, and generates a third uplink optical signal for backhaul.

[0043] The first ROF module of the expansion unit EU in this system includes multiple ROF optical ports. These ports employ multi-path ROF parallel output, allowing a single expansion unit EU to cover multiple independent coverage areas or buildings. This significantly enhances coverage capabilities compared to existing single-path output solutions, making it suitable for large-scale deployment scenarios (e.g., building, community, and residential coverage, FTTR+5G convergence, multi-area coverage, etc.). The baseband signal is converted to a radio frequency signal in real-time within the expansion unit EU. After processing by the first ROF module, it undergoes ROF analog optical transmission, achieving end-to-end latency controllable to within 300 nanoseconds, resulting in excellent real-time system performance. The system also features a 4G / 5G dual-mode BBU unit, supporting integrated 4G and 5G dual-mode coverage. A single system can simultaneously support existing networks (e.g., 4G networks) and newly built networks (e.g., 5G networks), effectively improving equipment utilization and reducing network upgrade and maintenance costs. This system can fully reuse the operator's existing PON network infrastructure without the need to lay new fiber optic cables or modify existing lines, which can greatly reduce construction and deployment costs.

[0044] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0045] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A 4G / 5G signal home coverage system based on ROF analog optical transmission and PON network, characterized in that... Includes: ROF analog photonic system, PON broadband access subsystem and multiple first multiplexers / demultiplexers; The PON broadband access subsystem includes an optical line terminal (OLT) device, a multi-channel passive optical distribution (ODN) network, and multiple optical network units (ONU) devices. The OLT device includes multiple OLT optical ports, and each OLT optical port corresponds one-to-one with one of the passive optical distribution (ODN) networks. The ROF analog photonic system includes a base station and multiple user terminals (UEs). The base station includes a 4G / 5G dual-mode BBU unit, an extension unit (EU), and multiple remote units (ROFs) connected optically in sequence. Each extension unit (EU) includes a first ROF module with multiple ROF optical ports, a standard digital optical port, a digital-to-analog converter (DAC), and a radio frequency (RF) power distribution module. Each ROF optical port and an OLT optical port are optically connected to a first multiplexer / demultiplexer (DMP). The standard digital optical port transmits the dual-mode baseband digital signal from the 4G / 5G dual-mode BBU unit to the extension unit (EU). The DAC converts the dual-mode baseband digital signal into a downlink dual-mode RF signal and then sends it to the RF power distribution module. The RF power distribution module divides the downlink dual-mode RF signal into multiple dual-mode baseband RF signals and then sends them to the first ROF module. Each of the remote units includes a second multiplexing / splitting module and a second ROF module, wherein: In the downlink direction, the 4G / 5G dual-mode BBU unit transmits the obtained dual-mode baseband digital signal to the extension unit EU to obtain multiple downlink dual-mode radio frequency signals. Then, it sends the signal to the first ROF module to convert the multiple downlink dual-mode radio frequency signals into multiple first downlink optical signals with the same first wavelength. These signals are then output in parallel through the multiple ROF optical ports. After being combined with the second downlink optical signals with the second wavelengths output in parallel through the multiple OLT optical ports, the signals are multiplexed through multiple first multiplexers and demultiplexers. Finally, the signals are multiplexed through multiple passive optical distribution network (ODN) networks and transmitted sequentially to multiple remote units and multiple user terminals (UEs). In the uplink direction, for any of the remote units, after the uplink dual-mode radio frequency signal transmitted by the user terminal UE is converted into a first uplink optical signal of the third wavelength by the second ROF module, it is combined with the second uplink optical signal of the fourth wavelength of the optical network unit ONU device by the second multiplexing and demultiplexing module, and then multiplexed through the passive optical distribution network (ODN) to be transmitted to the first multiplexer and demultiplexer for demultiplexing. Finally, it is sent by the first ROF module to the 4G / 5G dual-mode BBU unit.

2. The system according to claim 1, characterized in that, The standard digital optical port includes one of eCPRI, CPRI, and ORAN standard digital optical ports.

3. The system according to claim 1, characterized in that, The multi-path passive optical distribution ODN network includes a beam splitter, and the plurality of remote units are optically connected to the extension unit EU through the beam splitter.

4. The system according to claim 3, characterized in that, The beam splitter is capable of satisfying at least one of the beam splitting ratios of 1:8, 1:32, and 1:

64.

5. The system according to claim 1, characterized in that, Each of the remote units also includes a 4G / 5G broadband linear amplifier module and a wireless interface; The wireless interface is used to enable wireless communication between the remote unit and the user terminal (UE). The 4G / 5G broadband linear amplification module is used to amplify the downlink dual-mode radio frequency signal generated by the second ROF module after photoelectric conversion, and then transmit it to the wireless interface.

6. The system according to claim 1, characterized in that, Both the first multiplexer and the second multiplexer / demultiplexer module employ WDM (Wavelength Division Multiplexing) technology.

7. The system according to claim 1, characterized in that, The number of the multiple ROF optical ports is less than or equal to 8.

8. The system according to claim 1, characterized in that, The first wavelength, the second wavelength, the third wavelength, and the fourth wavelength are all different, and the third wavelength is a tunable wavelength of 1410nm ± 0.2nm.

9. The system according to claim 1, characterized in that, For the first downlink optical signal output from each of the ROF optical ports: The first downlink optical signal and a second downlink optical signal of the second wavelength output from the OLT optical port are combined by a corresponding first multiplexer / demultiplexer to generate a third downlink optical signal. This third downlink optical signal is then multiplexed through a corresponding passive optical distribution network (ODN) and transmitted to a remote unit. After being demultiplexed by the second multiplexing / demultiplexing module of the remote unit, the signal is transmitted to the connected optical network unit (ONU) and the second ROF module. The second ROF module then converts the first downlink optical signal obtained after demultiplexing into a downlink dual-mode radio frequency signal and sends it to the user terminal (UE).

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