Optical communication system and optical communication method

Abstract

The present application discloses an optical communication system and an optical communication method. The optical communication system comprises a first device, an optical splitter, and a plurality of second devices. The first device is used for sending a first optical signal, the first optical signal is split by the optical splitter and then transmitted to the plurality of second devices, and the first optical signal carries an analog radio-frequency signal. The plurality of second devices are used for respectively sending second optical signals, the plurality of second optical signals pass through the optical splitter and are then transmitted to the first device, and each second optical signal carries an analog radio-frequency signal. The optical signals communicated between the first device and the second devices carry the analog radio-frequency signals, the analog radio-frequency signals do not need to be converted into digital signals, encapsulated into an optical protocol frame format and then modulated into optical signals, and the communication between the first device and the second devices therefore does not involve an optical protocol conversion process of encapsulation and decapsulation in an optical protocol frame format, so that the service latency of the system is reduced, the structure of the system is simpler, and the power consumption and costs are reduced.

Description

An optical communication system and an optical communication method

[0001] The present application claims priority to the Chinese patent application No. 202411392962.6, filed on September 30, 2024, and entitled "An optical communication system and an optical communication method", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of optical communication, and in particular to an optical communication system and an optical communication method. BACKGROUND

[0003] In recent years, the fiber to the room (FTTR) technology is increasingly accepted by the majority of users due to its good coverage and good user experience. The traditional FTTR architecture adopts a point to multi-point (P2MP) digital networking technology. A master device is connected to multiple slave devices through an optical splitter and an optical fiber. The master device and the slave devices communicate with each other based on a digital protocol and transfer digital signals. The master device transmits digital signals to all slave devices in the downlink direction through broadcasting. Each slave device transmits digital signals to the master device in time division multiplexing (TDMA) mode. The master device and the slave devices interact through a determined protocol and data frame format. The master device centrally manages and controls the slave devices. The master device and the slave devices can provide independent Wi-Fi access services.

[0004] Analysis of the data flow of the entire network shows that the master device is the entrance and exit of the entire network data. In the downlink direction, part of the entrance data is directly given to the Wi-Fi module of the master device for transceiving processing, and the other part of the entrance data is encapsulated into an optical protocol frame format, then carried and sent to the slave device by the optical link. After receiving the optical protocol frame format, the slave device parses the data carried by the frame format and transmits it to the Wi-Fi module of the slave device for transceiving processing. The exit processing flow of the uplink data is just the opposite of the above process. The master device forwards the data received by the entire network to the network of the upper layer through the uplink optical port.

[0005] From the above data flow analysis result, it can be seen that the optical link in the FTTR scenario carries digital signals. The master device and the slave device involve an optical protocol conversion process of encapsulation and decapsulation of the optical protocol frame format, which increases the service delay of the system, the system structure is relatively complex, and the power consumption and cost are increased. SUMMARY

[0006] The present application provides an optical communication system and an optical communication method, which reduces the service delay of the system, the system structure is simpler, and the power consumption and cost are reduced.

[0007] In a first aspect, the present application provides an optical communication system, comprising a first device, an optical splitter and a plurality of second devices. The first device is configured to transmit a first optical signal, the first optical signal carrying an analog radio frequency signal, and the first optical signal is split by the optical splitter and transmitted to the plurality of second devices respectively. The plurality of second devices are configured to transmit a second optical signal respectively, each of the second optical signals carrying an analog radio frequency signal, and the plurality of second optical signals are transmitted to the first device after passing through the optical splitter, and the plurality of second optical signals have the same wavelength.

[0008] In this embodiment, the optical signal communicated between the first device and the second device carries an analog radio frequency signal, and the analog radio frequency signal does not need to be converted into a digital signal and encapsulated into an optical protocol frame format before being modulated into an optical signal. Therefore, the communication between the first device and the second device does not involve the optical protocol conversion process of optical protocol frame encapsulation and decapsulation, which reduces the service latency of the system, simplifies the structure of the system, and reduces the power consumption and cost. In addition, the optical communication system adopts a point to multi-point (P2MP) communication system, which is beneficial to reduce the deployment cost.

[0009] In some possible embodiments, the first device comprises a first baseband module, a first radio frequency module and a first bidirectional optical sub-assembly (BOSA). The first baseband module is configured to transmit a first baseband signal. The first radio frequency module is configured to generate a first radio frequency signal according to the first baseband signal, and the first radio frequency signal is an analog signal. The first BOSA is configured to generate a first optical signal according to the first radio frequency signal and transmit the first optical signal. The specific embodiment of the first device transmitting the first optical signal carrying the analog radio frequency signal is introduced herein, which ensures the realizability of the present application.

[0010] In some possible embodiments, the first device further comprises a coupler and a first antenna module, and a part of the first radio frequency signal after passing through the coupler is transmitted to the first BOSA, and another part of the first radio frequency signal after passing through the coupler is transmitted to the first antenna module. That is, the Wi-Fi access service of the first device and the Wi-Fi access service of the plurality of second devices share the baseband capability provided by the first baseband module, which not only ensures that the first device and the plurality of second devices both have the Wi-Fi access service, but also helps to reduce the structural complexity and power consumption of the first device.

[0011] In some possible implementation manners, the first device further includes a second baseband module, a second radio frequency module and a second antenna module. The second baseband module is configured to send a second baseband signal. The second radio frequency module is configured to generate a second radio frequency signal according to the second baseband signal, and transmit the second radio frequency signal to the second antenna module, the second radio frequency signal being an analog signal. That is, the first baseband module of the first device provides baseband capability for Wi-Fi access services of a plurality of second devices, and the second baseband module of the first device provides baseband capability for Wi-Fi access services of the first device itself, so that the Wi-Fi access services of the first device and the second devices can both enjoy better baseband capability.

[0012] In some possible implementation manners, the second radio frequency signal has the same frequency as the first radio frequency signal, that is, the first device can transmit two radio frequency signals of the same frequency, one of which is used for Wi-Fi access services of the first device itself, and the other of which is used for Wi-Fi access services of a plurality of second devices, and the two radio frequency signals of the same frequency are generated according to baseband signals provided by different baseband modules, which expands the implementation manners of the present solution and facilitates flexible division of a baseband pool of the first device according to actual needs.

[0013] In some possible implementation manners, the second device includes a second BOSA, a third antenna module and an amplifier. The third antenna module is configured to receive a third radio frequency signal, the third radio frequency signal being an analog signal. The amplifier is configured to amplify the third radio frequency signal. The second BOSA is configured to generate a second optical signal according to the amplified third radio frequency signal, and send the second optical signal. Here, a specific implementation manner in which the second device transmits a second optical signal carrying an analog radio frequency signal is introduced, which ensures the realizability of the present solution.

[0014] In some possible implementation manners, the optical communication system is applied to a fiber to the room (FTTR) scenario, the first device is a main fiber unit (MFU), and the second device is a sub fiber unit (SFU). That is, the present solution can be directly applied to the FTTR scenario, without changing the P2MP system architecture, so as to effectively reduce the service latency, power consumption and cost of the system.

[0015] In some possible implementation manners, if the frequency of the beat signal is close to the frequency of the analog radio frequency signal carried on the second optical signal after the plurality of second optical signals are combined by the optical splitter, the first device is configured to inform at least one second device to adjust the wavelength of the transmitted second optical signal. That is, considering that the wavelengths of the second optical signals transmitted by the plurality of second devices are the same, if there is a small wavelength difference Δλ between the wavelengths of the plurality of second optical signals, a beat component generated by the beat of the optical signals will appear in the spectrum after the plurality of second optical signals are combined, thereby causing obvious interference. Therefore, if the beat signal interference is found, the first device informs at least one second device to fine-tune the wavelength of the transmitted second optical signal, so that the wavelengths of the plurality of second optical signals are further staggered, thereby avoiding the interference of the beat signal.

[0016] In some possible implementation manners, the first device comprises a first BOSA, a filter, a detector, a comparator and a processor. The first BOSA is configured to convert the combined optical signal into an electrical signal. The filter is configured to filter the electrical signal to filter out the analog radio frequency signal carried on the second optical signal. The detector is configured to perform power detection on the filtered electrical signal. The comparator is configured to compare the power detection level with a reference level. If the absolute value of the power detection level is greater than or equal to the absolute value of the reference level, the processor is configured to inform at least one second device to adjust the wavelength of the transmitted second optical signal. For example, if the reference level and the power detection level are both positive numbers, the power detection level should be greater than or equal to the reference level. For another example, if the reference level and the power detection level are both negative numbers, the power detection level should be less than or equal to the reference level. Here, a specific way of dealing with beat interference is provided. The first device can find in advance that the frequency of the beat signal is close to the frequency of the analog radio frequency signal carried on the second optical signal by processing the received signal, so that effective response can be made before the beat signal actually causes interference, thereby improving the quality of the received signal of the first device.

[0017] In some possible implementation manners, the processor is specifically configured to control the first BOSA to suspend light emission, which means that if the second device finds that the first optical signal is not received, it is determined that the wavelength of the transmitted second optical signal needs to be fine-tuned. Here, a specific way of informing the second device to fine-tune the wavelength by the first device is provided, and the implementation is relatively simple.

[0018] In some possible implementation manners, the processor is specifically configured to modulate a pulse signal onto the first optical signal, and the pulse signal is used to instruct at least one second device to adjust the wavelength of the transmitted second optical signal. Here, another specific way of informing the second device to fine-tune the wavelength by the first device is provided, which enriches the implementation manners of the present solution.

[0019] In some possible implementation manners, the first device is specifically configured to convert the combined optical signal into an electrical signal, acquire a signal quality parameter of the electrical signal, and determine whether the frequency of the beat frequency signal is close to the frequency of the analog radio frequency signal carried on the second optical signal according to the signal quality parameter. Another specific manner for dealing with the beat frequency interference is provided herein. The first device determines whether the beat frequency signal interference has occurred by processing the received signal, which is equivalent to an effective response to the problem of the beat frequency signal interference when the problem actually occurs, so as to improve the quality of the signal received by the first device.

[0020] In some possible implementation manners, the signal quality parameter includes, but is not limited to, at least one of a received signal strength indication (RSSI), a modulation and coding scheme (MCS), and a packet error rate (PER).

[0021] In some possible implementation manners, the plurality of second devices transmit the second optical signals in time division, that is, the time periods in which any two second devices transmit the second optical signals are different. In this way, the plurality of second optical signals naturally do not generate the beat frequency signal due to simultaneous transmission, which is equivalent to avoiding the generation of the beat frequency signal from the source, so as to improve the quality of the signal received by the first device.

[0022] In a second aspect, an optical communication method is provided in the embodiments of the present application, and the optical communication method is applied to an optical communication system. The optical communication system includes a first device, an optical splitter, and a plurality of second devices. The method includes the following steps: transmitting, by the first device, a first optical signal, the first optical signal carrying an analog radio frequency signal, and the first optical signal being transmitted to the plurality of second devices after being split by the optical splitter; and transmitting, by the plurality of second devices, a plurality of second optical signals, each second optical signal carrying an analog radio frequency signal, and the plurality of second optical signals being transmitted to the first device after being split by the optical splitter, the plurality of second optical signals having the same wavelength.

[0023] In some possible implementation manners, the first device includes a first baseband module, a first radio frequency module, and a first BOSA. Transmitting, by the first device, the first optical signal includes the following steps: transmitting, by the first baseband module, a first baseband signal; generating, by the first radio frequency module, a first radio frequency signal according to the first baseband signal, the first radio frequency signal being an analog signal; and generating, by the first BOSA, the first optical signal according to the first radio frequency signal, and transmitting the first optical signal.

[0024] In some possible implementation, the first device further includes a coupler and a first antenna module, and a part of the first radio frequency signal after passing through the coupler is transmitted to the first BOSA, and another part of the first radio frequency signal after passing through the coupler is transmitted to the first antenna module.

[0025] In some possible implementation, the first device further includes a second baseband module, a second radio frequency module and a second antenna module, and the method further includes: transmitting, by the second baseband module, a second baseband signal. Generating, by the second radio frequency module, a second radio frequency signal according to the second baseband signal, and transmitting the second radio frequency signal to the second antenna module, the second radio frequency signal being an analog signal.

[0026] In some possible implementation, the frequency of the second radio frequency signal is the same as the frequency of the first radio frequency signal.

[0027] In some possible implementation, the second device includes a second BOSA, a third antenna module and an amplifier, and the method further includes: receiving, by the third antenna module, a third radio frequency signal, the third radio frequency signal being an analog signal. Amplifying, by the amplifier, the third radio frequency signal. Generating, by the second BOSA, a second optical signal according to the amplified third radio frequency signal, and transmitting the second optical signal.

[0028] In some possible implementation, the optical communication system is applied to an FTTR scene, the first device is an MFU, and the second device is an SFU.

[0029] In some possible implementation, the method further includes: if the frequency of the beat signal after the plurality of second optical signals passing through the optical coupler is close to the frequency of the analog radio frequency signal carried on the second optical signal, notifying, by the first device, at least one second device to adjust the wavelength of the transmitted second optical signal.

[0030] In some possible implementation, the first device includes a first BOSA, a filter, a detector, a comparator and a processor. The method further includes: converting, by the first BOSA, the combined optical signal into an electrical signal; filtering, by the filter, the electrical signal to filter out the analog radio frequency signal carried on the second optical signal; performing power detection on the filtered electrical signal by the detector; comparing, by the comparator, the power detection level value with a reference level value; and if the absolute value of the power detection level value is greater than or equal to the absolute value of the reference level value, notifying, by the processor, at least one second device to adjust the wavelength of the transmitted second optical signal.

[0031] In some possible implementation, notifying, by the processor, at least one second device to adjust the wavelength of the transmitted second optical signal includes: controlling, by the processor, the first BOSA to suspend light emission.

[0032] In some possible implementation, the informing, by the processor, the at least one second device to adjust the wavelength of the transmitted second optical signal comprises: modulating, by the processor, a pulse signal onto the first optical signal, the pulse signal being used to instruct the at least one second device to adjust the wavelength of the transmitted second optical signal.

[0033] In some possible implementation, the method further comprises: converting, by the first device, the combined optical signal into an electrical signal, and acquiring a signal quality parameter of the electrical signal, and determining whether the frequency of the beat signal is close to the frequency of the analog radio frequency signal carried on the second optical signal according to the signal quality parameter.

[0034] In some possible implementation, the signal quality parameter comprises, but is not limited to, at least one of the following parameters: RSSI, MCS and PER.

[0035] In some possible implementation, the plurality of second devices transmit the second optical signal in time division, that is, the time periods in which any two second devices transmit the second optical signal are different.

[0036] In the present application, the optical communication system comprises a first device, an optical splitter and a plurality of second devices. In the downlink direction, the first device is configured to transmit a first optical signal, the first optical signal is split by the optical splitter and transmitted to the plurality of second devices, wherein the first optical signal carries an analog radio frequency signal. In the uplink direction, the plurality of second devices are configured to transmit a plurality of second optical signals, and the plurality of second optical signals are transmitted to the first device after passing through the optical splitter, wherein each of the plurality of second optical signals carries an analog radio frequency signal. As can be seen, the optical signals communicated between the first device and the second devices carry analog radio frequency signals, and there is no need to convert the analog radio frequency signals into digital signals and encapsulate them into optical protocol frame formats before modulating them into optical signals. Therefore, the communication between the first device and the second devices does not involve the optical protocol conversion process of optical protocol frame format encapsulation and decapsulation, thereby reducing the service latency of the system, simplifying the structure of the system, and reducing the power consumption and cost. In addition, the optical communication system adopts a P2MP communication system, which is conducive to reducing the deployment cost. BRIEF DESCRIPTION OF DRAWINGS

[0037] FIG. 1 is a schematic diagram of the system architecture of FTTH;

[0038] FIG. 2 is a schematic diagram of the system architecture of FTTR;

[0039] FIG. 3 is a schematic diagram of one architecture of the optical communication system in the present application;

[0040] FIG. 4 is a schematic diagram of another architecture of the optical communication system in the present application;

[0041] FIG. 5 is a schematic diagram of the beat frequency interference of the multiple uplink optical signals in the present application;

[0042] Fig. 6 is another architecture of the optical communication system according to an embodiment of the present application;

[0043] Fig. 7 is another architecture of the optical communication system according to an embodiment of the present application;

[0044] Fig. 8 is an embodiment of the optical communication method according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] The present application provides an optical communication system and an optical communication method. The optical communication system is a point to multi-point (P2MP) communication system, and specifically includes a first device and a plurality of second devices. The optical signal communicated between the first device and the second devices carries analog radio frequency signals, and the analog radio frequency signals do not need to be converted into digital signals and encapsulated into optical protocol frame formats before being modulated into optical signals. Therefore, the communication between the first device and the second devices does not involve optical protocol conversion processes of encapsulation and decapsulation of optical protocol frame formats, which reduces the service latency of the system, simplifies the structure of the system, and reduces the power consumption and cost. In addition, the P2MP communication system is also conducive to reducing the deployment cost.

[0046] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and are not intended to limit a specific order or sequence. It should be understood that the above terms can be interchanged under appropriate circumstances, so that the embodiments described in the present application can be implemented in an order other than that described in the present application. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] It should be understood that the optical communication system provided by the embodiments of the present application can be applied in various P2MP optical communication scenarios. For example, in a fiber to the home (FTTH) scenario, the first device is an optical line terminal (OLT), and the second device is an optical network unit (ONU). For another example, in a fiber to the room (FTTR) scenario, the first device is a master gateway, and the second device is a slave gateway. The master gateway can also be referred to as a main fiber unit (MFU), and the slave gateway can also be referred to as a sub fiber unit (SFU). For another example, in a radio over fiber (ROF) scenario, the first device is a baseband unit (BBU), and the second device is a remote radio unit (RRU). For another example, in a distributed Wi-Fi scenario, the first device is a distributed access point (DAP), and the second device is an optic remote unit (ORU). The optical communication system provided by the embodiments of the present application can be mainly applied in the FTTR scenario, and the FTTR scenario will be described in detail below.

[0048] FIG. 1 is a schematic diagram of a system architecture of FTTH. The OLT is connected with a network side device (such as a switch or a router) at an upper layer, and is connected with one or more optical distribution networks (ODNs) at a lower layer. The ODN includes a passive optical splitter for optical power distribution, a trunk fiber connected between the passive optical splitter and the OLT, and branch fibers connected between the passive optical splitter and the ONUs. When transmitting data downward, the ODN transmits data transmitted downward by the OLT to each ONU through the optical splitter, and the ONU selectively receives the downward data carrying its own identifier. When transmitting data upward, the ODN combines optical signals transmitted by the N ONUs into one optical signal and transmits the optical signal to the OLT. The ONU provides a user side interface for terminal access and is connected with the ODN.

[0049] On the basis of FTTH, in order to solve the problem of Wi-Fi coverage of a home network, the optical fiber can be further extended to a room of a household, and the ONU is installed in the room. This application scenario is referred to as FTTR.

[0050] Fig. 2 is a schematic diagram of a system architecture of FTTR. The FTTR network and the FTTH network can be regarded as two-level systems. The OLT in the first-level system (FTTH) is deployed in the central machine room, and the ONU is deployed in the information box of the home. The master gateway in the second-level system (FTTR) can be deployed in the information box of the home instead of the ONU in the FTTH, which has similar functions as the OLT in the FTTH scenario, and also has similar functions as the ONU in the FTTH scenario. That is to say, the master gateway in the FTTR is a device with OLT and ONU functions, which can be used as a network device that connects FTTH and FTTR. The slave gateway in the FTTR can be deployed in each room of the home for connection with the terminal, which is essentially the same type of network device as the ONU in the FTTH. The difference is that the ONU in the FTTH is generally deployed in the information box, and there is usually an access point (AP) between the terminal and the ONU. The slave gateway in the FTTR enters each room and has the function of the AP, and can directly connect with the terminal through Wi-Fi. Specifically, the master gateway transmits downlink optical signals to all slave gateways through broadcast in the downlink direction, each slave gateway transmits uplink optical signals to the master gateway through time division multiple access (TDMA) in time division manner, the master gateway centrally manages and controls the slave gateways, and the master gateway and the slave gateways can provide independent Wi-Fi access services respectively.

[0051] It should be understood that multiple slave gateways can be deployed in the FTTR, and each slave gateway is connected to the branch port of the corresponding optical splitter. Moreover, the number of optical splitters in the FTTR is not limited by the present application, and the master gateway is connected to the optical splitters in a cascading manner. The master gateway can realize unified management and configuration of all slave gateways. For example, the master gateway as the control center of the home network can configure the Wi-Fi hotspots of the whole house as a unified network, optimize the channel to avoid interference, and control the roaming and switching of the terminal to reduce the network switching time and improve the user experience.

[0052] FIG. 3 is a schematic diagram of an architecture of an optical communication system according to an embodiment of the present application. As shown in FIG. 3, the optical communication system includes a first device, an optical splitter, and a plurality of second devices. The present application does not limit the number of second devices, and FIG. 3 shows two second devices as an example. In the downstream transmission direction, the first device transmits a first optical signal, and the first optical signal is split by the optical splitter and transmitted to the plurality of second devices. In the upstream transmission direction, the plurality of second devices respectively transmit second optical signals, and the plurality of second optical signals are transmitted to the first device after passing through the optical splitter. It should be understood that the plurality of second optical signals have the same wavelength, for example, the wavelength of the second optical signal is 1310 nm; and the first optical signal and the second optical signal have different wavelengths, for example, the wavelength of the first optical signal is 1490 nm.

[0053] It should be noted that the first optical signal and the second optical signal both carry analog radio frequency signals, rather than digital radio frequency signals. That is, the first device modulates the downstream analog radio frequency signal onto an optical carrier to obtain the first optical signal, and the second device modulates the upstream analog radio frequency signal onto an optical carrier to obtain the second optical signal. In this way, neither the upstream transmission direction nor the downstream transmission direction needs to convert the analog radio frequency signal into a digital signal and encapsulate it into an optical protocol frame format before modulating it into an optical signal. Therefore, the communication between the first device and the second device does not involve the optical protocol conversion process of optical protocol frame format encapsulation and decapsulation, which reduces the service latency of the system, simplifies the system structure, and reduces power consumption and cost. The specific embodiments of the upstream transmission direction and the downstream transmission direction in the optical communication system are described in detail below.

[0054] As shown in FIG. 3, in the downlink transmission direction, the first baseband module 11 in the first device transmits a first baseband signal, where the first baseband signal can be an analog signal or a digital signal, which is not limited herein. The first radio frequency module 12 generates a first radio frequency signal according to the first baseband signal, where the first radio frequency signal is an analog signal, and if the first baseband signal is a digital signal, the first radio frequency module 12 converts the first baseband signal into an analog signal to generate the first radio frequency signal. The first bidirectional optical sub-assembly (BOSA) 14 generates a first optical signal according to the first radio frequency signal and transmits the first optical signal. The first BOSA 14 includes a laser diode (LD) 141 and a photoelectric diode (PD) 142, and in the downlink transmission direction, the switch 13 in the first device is in communication with the LD 141, and the first radio frequency signal is modulated onto the optical carrier emitted by the LD 141 to form the first optical signal. The first optical signal is split by the optical splitter and transmitted to a plurality of second devices. Taking one of the second devices as an example, the second BOSA 21 in the second device includes an LD 211 and a PD 212, and the PD 212 converts the first optical signal into a first radio frequency signal. The first radio frequency signal is amplified by the power amplifier (PA) 25 and sent to the third antenna module 22, and the third antenna module 22 emits the first radio frequency signal to facilitate the station (STA) to receive. In the downlink transmission direction, the switch 23 in the second device is in communication with the PA 25.

[0055] As shown in FIG. 3, in the uplink transmission direction, the switch 23 in the second device is in communication with the low noise amplifier (LNA) 24 and the third antenna module 22, the third antenna module 22 receives a third radio frequency signal from the STA, and the third radio frequency signal is an analog signal. The third radio frequency signal is amplified by the LNA 24 and transmitted to the second BOSA 21, and the third radio frequency signal is modulated onto the optical carrier emitted by the LD 211 to form a second optical signal. The second optical signals from a plurality of second devices are transmitted to the first device after being split by the optical splitter. In the uplink transmission direction, the switch 13 in the first device is in communication with the PD 142, and the PD 142 converts the input second optical signal into an analog radio frequency signal. The analog radio frequency signal is converted into a baseband signal by the first radio frequency module 12 and sent to the first baseband module 11 for processing.

[0056] In some possible implementation manners, the first device can also provide independent Wi-Fi access services, and the second baseband module 15 of the first device sends a second baseband signal. The second radio frequency module 16 generates a second radio frequency signal according to the second baseband signal, where the second radio frequency signal is an analog signal. The second antenna module 17 sends the second radio frequency signal, so as to be received by the STA. That is, the baseband pool of the first device can include one or more baseband modules, and the specific number of the divided baseband modules in the first device depends on actual application requirements, which is not limited here. Taking FIG. 3 as an example, the first baseband module 11 of the first device provides baseband capability for Wi-Fi access services of the plurality of second devices, and the second baseband module 15 of the first device provides baseband capability for Wi-Fi access services of the first device itself.

[0057] FIG. 4 is another architecture diagram of an optical communication system in an embodiment of the present application. Different from the architecture shown in FIG. 3, as shown in FIG. 4, in the downlink transmission direction, the first baseband module 11 in the first device sends a first baseband signal, and the first radio frequency module 12 generates a first radio frequency signal according to the first baseband signal. Part of the first radio frequency signal after passing through the coupler 18 is transmitted to the first BOSA 14, and another part of the first radio frequency signal after passing through the coupler 18 is transmitted to the first antenna module 19. That is, the Wi-Fi access services of the first device itself and the Wi-Fi access services of the plurality of second devices share the baseband capability provided by the first baseband module 11.

[0058] It should be noted that in the embodiments shown in FIG. 3 and FIG. 4, the embodiments of the present application do not limit the frequency of the radio frequency signal emitted by each radio frequency module in the first device. In one possible scenario, the frequencies of the radio frequency signals emitted by all the radio frequency modules in the first device are the same, for example, all the radio frequency modules in the first device emit a radio frequency signal of 5 GHz or emit a radio frequency signal of 2 GHz. In another possible scenario, the frequencies of the radio frequency signals emitted by different radio frequency modules in the first device are different, for example, part of the radio frequency modules in the first device emit a radio frequency signal of 5 GHz, and another part of the radio frequency modules in the first device emit a radio frequency signal of 2 GHz. Wherein, the radio frequency module in the first device can be a radio frequency front end module (FEM).

[0059] It should be noted that in the embodiments shown in FIG. 3 and FIG. 4, the switch 13 in the first device can be controlled by the first radio frequency module 12, as shown by the dashed arrow between the first radio frequency module 12 and the switch 13 in FIG. 3 and FIG. 4. In this case, the switch 13 is in communication with the PD 142 by default, i.e., the first device is in the uplink receiving mode by default. When the first radio frequency module 12 receives the first baseband signal from the first baseband module 11, it indicates that the first device is to switch to the downlink transmitting mode, and then the first radio frequency module 12 sends a control signal to the switch 13 to control the switch 13 to switch to communication with the LD 141.

[0060] FIG. 5 is a schematic diagram of the beat frequency generated by multiple uplink optical signals in the embodiments of the present application. It should be understood that although multiple second devices are required to send second optical signals with the same wavelength, the actual wavelengths of the second optical signals sent by the second devices can have some errors. If multiple second optical signals are sent to the first device at the same time, and there is a very small wavelength difference Δλ between the wavelengths of the multiple second optical signals, then after the multiple second optical signals are combined by the optical splitter, a beat frequency component generated by the beat frequency of the optical signals will appear in the frequency spectrum. Taking the case of two second optical signals as an example, as shown in FIG. 5, the wavelength of one of the second optical signals is λ, and the wavelength of the other second optical signal is λ+Δλ. When Δλ << λ, the frequency of the beat frequency signal is f = (c / λ 2 )Δλ. When the amplitudes of the two second optical signals are close and Δλ is small, the frequency of the beat frequency signal can be close to the frequency of the analog radio frequency signal carried on the second optical signal, and the strength of the beat frequency signal can be close to or even stronger than the analog radio frequency signal carried on the second optical signal, so that the beat frequency signal will bring obvious interference. For example, the frequency of the analog radio frequency signal carried on the second optical signal is 5.8 GHz, and the wavelength of the second optical signal is 1310 nm. Due to differences in the factory batch, the actual working wavelengths of the second optical signals from different second devices have a deviation of 2 nm, and the working wavelength of the second optical signal also changes with temperature. In actual operation, if the working wavelengths of two or more second optical signals are very close, and the frequency of the beat frequency signal generated after the combination falls within 6 GHz, then the Wi-Fi signal quality will be severely affected. Therefore, the embodiments of the present application provide several specific ways to cope with the interference of the beat frequency signal, which will be described in detail below.

[0061] In a first possible implementation, the first device can discover in advance that the frequency of the beat frequency signal is close to the frequency of the analog radio frequency signal carried on the second optical signal by processing the received signal, and then the first device notifies at least one second device to fine-tune the wavelength of the emitted second optical signal, so that the wavelengths of the multiple second optical signals are further staggered. In this way, effective countermeasures can be taken before the beat frequency signal actually causes interference, and the quality of the signal received by the first device is improved.

[0062] Fig. 6 is another schematic diagram of the optical communication system in the embodiment of the present application. As shown in Fig. 6, the first device further comprises a coupler 100, a filter 101, a detector 102, a comparator 103 and a processor 104. Specifically, the first BOSA 14 receives the combined optical signal from the optical combiner, and the PD 142 converts the combined optical signal into an electrical signal, wherein the electrical signal includes the electrical signal corresponding to the beat signal and the analog RF signal carried on each of the second optical signals if the beat signal is generated. A part of the electrical signal after the coupler 100 is transmitted to the switch 13 and further transmitted to the first RF module 12 and the first baseband module 11. Another part of the electrical signal after the coupler 100 is transmitted to the filter 101. The filter 101 filters the input electrical signal to filter out the analog RF signal carried on each of the second optical signals, so that the detector 102 detects the electrical signal corresponding to the beat signal. For example, if the frequency of the analog RF signal carried on the second optical signal is 5.8 GHz, the filter 101 can filter out the input signal with a frequency within 6 GHz. The detector 102 detects the power of the filtered electrical signal and outputs the level value to the comparator 103. The comparator 103 compares the level value output by the detector 102 with the reference level value and outputs 0 or 1 to the processor 104 according to the decision result. If the absolute value of the power detection level value is greater than or equal to the absolute value of the reference level value, the comparator 103 outputs 1, which means that the frequency of the beat signal has approached the frequency of the analog RF signal carried on the second optical signal, and the processor 104 needs to inform at least one second device to fine-tune the wavelength of the transmitted second optical signal. If the absolute value of the power detection level value is less than or equal to the absolute value of the reference level value, the comparator 103 outputs 0, which means that the frequency of the beat signal is quite different from the frequency of the analog RF signal carried on the second optical signal, and there is no problem of beat signal interference.

[0063] It should be noted that the processor 104 can specifically control the LD 141 to notify at least one second device to fine-tune the wavelength of the emitted second optical signal, as shown by the dashed arrow between the processor 104 and the LD 141 in FIG. 6. It should be understood that the second device can fine-tune the wavelength of the emitted second optical signal according to a pre-designed rule after receiving the notification from the first device, and the rule can specify the direction and size of the wavelength adjustment, for example, the rule can determine to increase the wavelength or decrease the wavelength, and the amplitude of the change is more than 0.1 nm, which is not limited here. In actual applications, if the beat signal interference problem is found, as long as at least one second device fine-tunes the wavelength of the emitted second optical signal, if multiple second devices fine-tune the wavelength, a certain rule can also be designed to further stagger the wavelengths of the multiple second optical signals, which is not limited here. The present application does not limit the specific implementation of the second device fine-tuning the wavelength of the emitted second optical signal, for example, the wavelength of the second optical signal can be fine-tuned by adjusting the operating temperature or bias current of the LD 211.

[0064] As an example, if the processor 104 determines that there is a beat signal interference problem according to the output result of the comparator 103, the processor 104 controls the LD 141 to suspend light emission, at this time, all second devices do not receive the downlink first optical signal. In order to further determine which second device needs to fine-tune the wavelength, some decision mechanisms can also be designed for the second device, which are not limited here. For example, if the downlink first optical signal is not received, some second devices will trigger the light to be on, and some second devices will not trigger the light to be on, and the second device that triggers the light to be on needs to fine-tune the wavelength of the emitted second optical signal.

[0065] As another example, if the processor 104 determines that there is a beat signal interference problem according to the output result of the comparator 103, the processor 104 controls the LD 141 to modulate a pulse signal onto the first optical signal, wherein the pulse signal has a small amplitude and a low frequency. The second device can detect the pulse signal through demodulation and filtering operations after receiving the first optical signal, and the second device can determine that the wavelength of the emitted second optical signal needs to be fine-tuned. Similar to the previous example, in order to further determine which second device needs to fine-tune the wavelength, some decision mechanisms can also be designed for the second device, which are not limited here. For example, if the pulse signal is detected, some second devices will trigger the light to be on, and some second devices will not trigger the light to be on, and the second device that triggers the light to be on needs to fine-tune the wavelength of the emitted second optical signal.

[0066] In the second possible implementation, the first device determines whether the beat signal interference has occurred by processing the received signal. Then, the first device notifies at least one second device to fine tune the wavelength of the transmitted second optical signal, so that the wavelengths of the multiplexed second optical signals are further staggered. That is, unlike the prevention mechanism introduced in the first implementation above, the second implementation is an effective response when the beat signal interference has actually occurred, to improve the quality of the received signal of the first device.

[0067] Fig. 7 is another architecture of the optical communication system in the embodiments of the present application. Specifically, the first BOSA 14 receives the combined optical signal from the optical combiner, and the PD 142 converts the combined optical signal into an electrical signal. The electrical signal is transmitted to the switch 13, and further transmitted to the first baseband module 11 through the first radio frequency module 12. The first baseband module 11 detects the input electrical signal, and specifically can detect parameters related to signal quality, which are affected by the beat signal interference and have some obvious characteristics. These parameters include, but are not limited to, at least one of received signal strength indication (RSSI), packet error rate (PER), and modulation and coding scheme (MCS). For example, if at least one of the characteristics that RSSI is always large, PER is always large, and MCS is continuously reduced occurs, it can be determined that the beat signal interference has occurred. At this time, the first baseband module 11 can specifically control the LD 141 to notify at least one second device to fine tune the wavelength of the transmitted second optical signal, as shown by the dashed arrow between the first baseband module 11 and the LD 141 in Fig. 7. It should be understood that the second device can fine tune the wavelength of the transmitted second optical signal according to the pre-designed rules after receiving the notification of the first device, which can be referred to the related introduction of the embodiment shown in Fig. 6, and will not be repeated here. It should also be understood that the first baseband module 11 controls the LD 141 in a similar manner to the processor 104 controlling the LD 141 in the embodiment shown in Fig. 6, which can be referred to the related introduction of the embodiment shown in Fig. 6, and will not be repeated here.

[0068] In a third possible implementation, it can be considered that the multiple second devices send the second optical signals in time division, that is, the time periods for any two second devices to send the second optical signals are different. In this way, the multiple second optical signals will not naturally combine to generate the beat frequency signal due to simultaneous transmission, which is equivalent to avoiding the generation of the beat frequency signal from the source. Specifically, the second device can select whether to turn on the LD 211 according to the actual time of receiving the third radio frequency signal from the STA, rather than always turning on the LD 211, which is equivalent to that the second device can flexibly control the time of sending the second optical signal according to the actual scene. In a possible scenario, taking FIG. 3 as an example, if the two second devices do not receive the third radio frequency signal from the STA at the same time, each second device can turn on the LD 211 at the same time of receiving the third radio frequency signal, and the two second devices naturally send the second optical signals in time division, and will not generate the beat frequency signal. In another possible scenario, taking FIG. 3 as an example, if the two second devices receive the third radio frequency signal from the STA at the same time, the two second devices need to turn on the LD 211 of each second device in time division, so that the two second devices also send the second optical signals in time division, and will not generate the beat frequency signal.

[0069] The embodiment of the present application also provides an optical communication method. The optical communication method is applied to any optical communication system introduced in the above embodiments. FIG. 8 is a schematic diagram of an embodiment of an optical communication method provided by the embodiment of the present application. In this embodiment, the optical communication method comprises the following steps.

[0070] 1. A first device sends a first optical signal carrying an analog radio frequency signal.

[0071] Specifically, the first optical signal is transmitted to the multiple second devices after being branched by the optical splitter, and then the second optical signal is optoelectronically converted by the second device to obtain the analog radio frequency signal. Further, the analog radio frequency signal is amplified by the second device and sent into the antenna module for emission, so as to be received by the STA.

[0072] In some possible implementations, the first device can also provide independent Wi-Fi access services, that is, the analog radio frequency signal can be sent into the antenna module for emission by the first device, so as to be received by the STA. As an example, the analog radio frequency signal carried on the first optical signal and the analog radio frequency signal sent into the antenna module for emission can share the baseband capability provided by the same baseband module in the first device. As another example, the analog radio frequency signal carried on the first optical signal and the analog radio frequency signal sent into the antenna module for emission respectively adopt the baseband capability provided by different baseband modules in the first device.

[0073] 2. The multiple second devices respectively send second optical signals carrying analog radio frequency signals.

[0074] Specifically, the second optical signals from the plurality of second devices are transmitted to the first device after passing through the optical splitter, and then the combined optical signals are converted into analog radio frequency signals by the first device, and further converted into baseband signals for processing.

[0075] In some possible implementations, considering that the plurality of second optical signals will generate a beat frequency component in the spectrum after being combined, obvious interference will be caused. As an example, the first device can process the received signals, so that it can be found in advance that the frequency of the beat frequency signal is close to the frequency of the analog radio frequency signal carried on the second optical signal, and then the first device can notify at least one second device to fine-tune the wavelength of the transmitted second optical signal, so that the wavelengths of the plurality of second optical signals are further staggered. For details, reference can be made to the related description of the embodiment shown in FIG. 6, which will not be repeated here. As another example, the first device can process the received optical signals, so as to determine whether the beat frequency signal interference problem has occurred, and then the first device can notify at least one second device to fine-tune the wavelength of the transmitted second optical signal, so that the wavelengths of the plurality of second optical signals are further staggered. For details, reference can be made to the related description of the embodiment shown in FIG. 7, which will not be repeated here. As yet another example, the plurality of second devices can be configured to transmit the second optical signals in time division mode, that is, the time periods for transmitting the second optical signals by any two second devices are different. In this way, the plurality of second optical signals will not generate beat frequency signals due to simultaneous transmission, which is equivalent to avoiding the generation of beat frequency signals from the source.

[0076] In one possible scenario, the first device can suspend light emission, so that the second device cannot receive the downlink first optical signal, and the second device can determine that the wavelength of the transmitted second optical signal needs to be fine-tuned. In another possible scenario, the first device can modulate a pulse signal onto the first optical signal, and the second device can detect the pulse signal through demodulation and filtering after receiving the first optical signal, and the second device can determine that the wavelength of the transmitted second optical signal needs to be fine-tuned.

[0077] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; even though the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application. The embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An optical communication system, characterized by, The application relates to an optical communication system. The system comprises a first device, a splitter and a plurality of second devices. The first device is configured to send a first optical signal, the first optical signal carrying an analog radio frequency signal, the first optical signal being transmitted to the plurality of second devices via the splitter. The plurality of second devices are configured to send a second optical signal respectively, each of the second optical signals carrying an analog radio frequency signal, the plurality of second optical signals being transmitted to the first device via the splitter, the plurality of second optical signals having the same wavelength.

2. The optical communication system of claim 1, wherein, The first device comprises a first baseband module, a first radio frequency module and a first bidirectional optical subassembly (BOSA). The first baseband module is configured to send a first baseband signal. The first radio frequency module is configured to generate a first radio frequency signal based on the first baseband signal, the first radio frequency signal being an analog signal. The first BOSA is configured to generate the first optical signal based on the first radio frequency signal and send the first optical signal.

3. The optical communication system of claim 2, wherein, The first device further comprises a coupler and a first antenna module, a part of the first radio frequency signal after passing through the coupler is transmitted to the first BOSA, and another part of the first radio frequency signal after passing through the coupler is transmitted to the first antenna module.

4. The optical communication system of claim 2 or 3, wherein, The first device further comprises a second baseband module, a second radio frequency module and a second antenna module. The second baseband module is configured to send a second baseband signal. The second radio frequency module is configured to generate a second radio frequency signal based on the second baseband signal and transmit the second radio frequency signal to the second antenna module, the second radio frequency signal being an analog signal.

5. The optical communication system of claim 4, wherein, The second radio frequency signal has the same frequency as the first radio frequency signal.

6. The optical communication system of any of claims 1 to 5, wherein, The second device comprises a second BOSA, a third antenna module and an amplifier. The third antenna module is configured to receive a third radio frequency signal, the third radio frequency signal being an analog signal. The amplifier is configured to amplify the third radio frequency signal. The second BOSA is configured to generate the second optical signal based on the amplified third radio frequency signal and send the second optical signal.

7. The optical communication system of any of claims 1 to 6, wherein, The optical communication system is applied to a fiber to the room (FTTR) scenario, the first device is a master optical unit (MFU), and the second device is a slave optical unit (SFU).

8. The optical communication system of any of claims 1 to 7, wherein, If the frequency of a beat signal after the plurality of second optical signals are combined via the splitter is close to the frequency of the analog radio frequency signal carried by the second optical signal, the first device is configured to notify at least one of the second devices to adjust the wavelength of the second optical signal sent by the second device.

9. The optical communication system of claim 8, wherein, The first device comprises a first BOSA, a filter, a detector, a comparator and a processor. The first BOSA is configured to convert the combined optical signal into an electrical signal. The filter is configured to filter the electrical signal to filter out the analog radio frequency signal carried by the second optical signal. The detector is configured to detect the power of the filtered electrical signal. The comparator is configured to compare the level value of the power detection with a reference level value. If an absolute value of the power detection level value is greater than or equal to an absolute value of the reference level value, the processor is configured to inform at least one of the second devices to adjust a wavelength of the second optical signal transmitted.

10. The optical communication system of claim 9, wherein, The processor is specifically configured to control the first BOSA to suspend light emission.

11. The optical communication system of claim 9, wherein, The processor is specifically configured to modulate a pulse signal onto the first optical signal, and the pulse signal is used to instruct at least one of the second devices to adjust a wavelength of the second optical signal transmitted.

12. The optical communication system of claim 8, wherein, The first device is specifically configured to convert the combined optical signal into an electrical signal, acquire a signal quality parameter of the electrical signal, and determine whether a frequency of the beat signal is close to a frequency of the analog radio frequency signal carried on the second optical signal according to the signal quality parameter.

13. The optical communication system of claim 12, wherein, The signal quality parameter includes at least one of a received signal strength indication (RSSI), a modulation and coding scheme (MCS), and a packet error rate (PER).

14. The optical communication system of any of claims 1-13, wherein, Any two of the second devices transmit the second optical signal in different time periods.

15. A method of optical communication, the method comprising: The optical communication method is applied to an optical communication system, and the optical communication system includes a first device, an optical splitter, and a plurality of second devices. The first device transmits a first optical signal, the first optical signal carries an analog radio frequency signal, and the first optical signal is split by the optical splitter and transmitted to the plurality of second devices. The plurality of second devices respectively transmit second optical signals, each of the second optical signals carries an analog radio frequency signal, and the plurality of second optical signals are combined by the optical splitter and transmitted to the first device, and the plurality of second optical signals have the same wavelength.

16. The method of claim 15, wherein, The first device includes a first baseband module, a first radio frequency module, and a first bidirectional optical subassembly (BOSA), and the first device transmits the first optical signal by: The first baseband module transmits a first baseband signal. The first radio frequency module generates a first radio frequency signal according to the first baseband signal, and the first radio frequency signal is an analog signal. The first BOSA generates the first optical signal according to the first radio frequency signal and transmits the first optical signal.

17. The method of claim 16, wherein, The first device further includes a coupler and a first antenna module, and a part of the first radio frequency signal after passing through the coupler is transmitted to the first BOSA, and another part of the first radio frequency signal after passing through the coupler is transmitted to the first antenna module.

18. The method of claim 16 or 17, wherein, The first device further includes a second baseband module, a second radio frequency module, and a second antenna module, and the method further includes: The second baseband module transmits a second baseband signal. The second radio frequency module generates a second radio frequency signal according to the second baseband signal and transmits the second radio frequency signal to the second antenna module, and the second radio frequency signal is an analog signal.

19. The method of claim 18, wherein, The second radio frequency signal has the same frequency as the first radio frequency signal.

20. The method of any one of claims 15-19, wherein, The second device includes a second BOSA, a third antenna module, and an amplifier, and the method further includes: The third antenna module receives a third radio frequency signal, and the third radio frequency signal is an analog signal. amplify the third radio frequency signal by the amplifier; generate the second optical signal according to the amplified third radio frequency signal by the second BOSA, and transmit the second optical signal.

21. The method of any one of claims 15-20, wherein, The optical communication system is applied to a fiber to the room (FTTR) scenario, the first device is a master optical device (MFU), and the second device is a slave optical device (SFU).

22. The method of any one of claims 15-21, wherein, The method further includes: If the frequency of the beat signal after the plurality of second optical signals are combined by the optical splitter is close to the frequency of the analog radio frequency signal carried on the second optical signal, the first device informs at least one of the second devices to adjust the wavelength of the transmitted second optical signal.

23. The method of claim 20, wherein, The first device includes a first BOSA, a filter, a detector, a comparator, and a processor, and the method further includes: The first BOSA converts the combined optical signal into an electrical signal; The filter filters the electrical signal to filter out the analog radio frequency signal carried on the second optical signal; The detector detects the power of the filtered electrical signal; The comparator compares the level value of the power detection with a reference level value; If the absolute value of the level value of the power detection is greater than or equal to the absolute value of the reference level value, the processor of the first device informs at least one of the second devices to adjust the wavelength of the transmitted second optical signal.

24. The method of claim 23, wherein, The processor of the first device informs at least one of the second devices to adjust the wavelength of the transmitted second optical signal, including: The processor controls the first BOSA to suspend light emission.

25. The method of claim 23, wherein, The processor of the first device informs at least one of the second devices to adjust the wavelength of the transmitted second optical signal, including: The processor modulates a pulse signal onto the first optical signal, and the pulse signal is used to instruct at least one of the second devices to adjust the wavelength of the transmitted second optical signal.

26. The method of claim 22, wherein, The method further includes: The first device converts the combined optical signal into an electrical signal, acquires a signal quality parameter of the electrical signal, and determines whether the frequency of the beat signal is close to the frequency of the analog radio frequency signal carried on the second optical signal according to the signal quality parameter.

27. The method of claim 26, wherein, The signal quality parameter includes at least one of a received signal strength indication (RSSI), a modulation and coding scheme (MCS), and a packet error rate (PER).

28. The method of any one of claims 15-27, wherein, Any two of the plurality of second devices transmit second optical signals in different time periods.

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