A communication system, apparatuses and methods

Abstract

The application discloses a communication system, related equipment and method. The communication system comprises a CO device and a plurality of RRHs. The plurality of RRHs form a ring network through optical fibers, and the CO device is connected to the ring network. The CO device is used for modulating a baseband signal onto N first optical carriers generated by the CO device to obtain N second optical carriers, and transmitting the N second optical carriers to the ring network through a first optical fiber. Any one of the plurality of RRHs is used for obtaining a target optical carrier from the received second optical carrier, converting the target optical carrier into an electrical signal, and transmitting the electrical signal as a downlink signal. The embodiment of the application realizes an all-optical communication system through the layout of optical devices on the architecture and through the optical ring network topology, and the communication system has a self-healing protection function.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a communication system, related equipment and methods. Background Technology

[0002] In the current mainstream wireless base station architecture, distributed base stations are the norm. The ramote radio head (RRH) and baseband unit (BBU) are primarily deployed via radio frequency extension. The interface between the BBU and RRH is called the fronthaul interface, which carries the traffic from the RRH to the BBU. There are several mainstream methods for carrying fronthaul traffic, such as the Common Public Radio Interface (CPRI), the Enhanced Common Public Radio Interface (eCPRI), and Radioover Fiber (ROF). These methods control traffic by adjusting functional deployment. Furthermore, different numbers of TRXs can lead to significant differences in fronthaul traffic. Changes in traffic between the BBU and RRH are the most important factor influencing future architectural changes.

[0003] From 2G and 3G to 4G, 5G, and the upcoming 6G, each generation of communication technology has continuously increased the demands on baseband computing power, and the requirements for transmission bandwidth and latency between BBUs are also higher. Due to the dramatic increase in fronthaul traffic, large-scale MIMO in the future will limit the current CPRI interface, necessitating consideration of new split points or even integrated base stations, or the introduction of low-cost optical technologies. In addition, current electronic components have reached a certain bottleneck in meeting the high bandwidth and computing demands of the future. The combination of wireless base stations and optical technologies is a key direction with huge potential and flexibility for future improvement.

[0004] ROF technology modulates an RF carrier onto an optical wave, which is then transmitted through optical fiber to the receiver. At the receiver, a photodetector performs photoelectric conversion to obtain the radio frequency signal, which is finally transmitted to the user terminal via an antenna. Figure 1 As shown, the ROF base station consists of two parts: the central office (CO) equipment and the RRH (Remote Radio Headquarters), which are connected by optical fiber. The modulation module, analog-to-digital converter (ADC), and digital-to-analog converter (DAC) of the radio frequency module are integrated into the CO equipment.

[0005] However, ROF base stations only transmit wireless signals over optical fibers. Most of the parts other than transmission still use electrical signal processing methods. CO equipment uses key electrical components such as DACs and ADCs. The processing of the critical mid-frequency radio frequency part still uses the processing methods of electrical components, which brings problems such as high cost, high power consumption, and limited bandwidth. Summary of the Invention

[0006] This application provides a communication system, related equipment, and method. This application implements an all-optical communication system by arranging optical devices in the architecture and using an optical ring network topology. The communication system also has a self-healing protection function.

[0007] In a first aspect, embodiments of this application provide a communication system, including a central office (CO) device and multiple ramote radio heads (RRHs), wherein the multiple RRHs form a ring network through optical fibers, and the CO device is connected to the ring network through at least two optical fibers; optionally, the at least two optical fibers include a first optical fiber and a second optical fiber.

[0008] A CO device is used to generate N first optical carriers, each with a different wavelength; and modulates a baseband signal onto the N first optical carriers to obtain N second optical carriers; and transmits the N second optical carriers to a ring network through a first optical fiber, so that the N second optical carriers are transmitted along a first direction on the ring network, where N is an integer greater than 0.

[0009] Any one of the multiple RRHs is used to obtain the target optical carrier from the received second optical carrier, transmit the optical carriers other than the target optical carrier in the received second optical carrier back to the ring network, convert the target optical carrier into an electrical signal, and transmit the electrical signal as a downlink signal.

[0010] Optionally, multiple RRHs can be connected end-to-end via optical fibers to form a ring network. Specifically, multiple RRHs can be connected end-to-end via optical fibers to form a closed ring network.

[0011] The baseband signal is the unmodulated signal emitted by the source; each of the N first optical carriers carries a radio frequency signal. The modulation module modulates the baseband signal onto the N first optical carriers to obtain N second optical carriers. Specifically, the modulation module modulates the baseband signal onto the radio frequency signal of each of the N first optical carriers to obtain N second optical carriers.

[0012] Optionally, the wavelength of the target optical carrier of the RRH is the same as the wavelength of the optical carrier required by the RRH, or the wavelength is obtained by the RRH from the received second optical carrier based on the wavelength selection information.

[0013] Optionally, the first direction is either clockwise or counterclockwise.

[0014] The architecture proposed in this application enables the redistribution of distributed base station functions. Compared to the existing BBU and RRU architecture, the baseband signal processing function of the BBU and the baseband signal mixing function of the RRU are processed on the CO device side. The RRH retains a few functions, such as signal transmission and reception, achieving high bandwidth, low cost, and low power consumption. At the same time, the CO device and RRH are implemented based on optical devices, which can eliminate the dependence of traditional base stations on high-performance electrical components.

[0015] In one feasible embodiment, the CO device is also used to transmit N second optical carriers to the ring network via a second optical fiber when a first optical fiber failure is detected.

[0016] When the first fiber fails, the second fiber is used as a backup fiber to replace the first fiber, thus achieving a self-healing function.

[0017] In one feasible embodiment, any two adjacent RRHs among multiple RRHs can be connected by one optical fiber or by two optical fibers to achieve bidirectional transmission of uplink and downlink signals. Connecting by two optical fibers can avoid interference between uplink and downlink optical signals.

[0018] In a feasible embodiment, any RRH is also used to obtain a seed optical signal based on the target optical carrier, modulate the received uplink signal onto the seed optical signal to obtain a third optical carrier, and transmit the third optical carrier to the CO device through a processing module.

[0019] The seed optical signal is obtained based on the target optical carrier, and the uplink signal is modulated onto the seed optical signal. Since the seed optical signal has the same frequency as the first optical carrier, the uplink and downlink optical carrier frequencies are synchronized through the same light source.

[0020] In one feasible embodiment, the CO device further includes: the processing module is connected to the CO device via a first optical fiber and a second optical fiber, and to a ring network;

[0021] The processing module is also used to control N second optical carriers to transmit in the ring network along a first direction and a second direction when an optical fiber fault is detected in the ring network, wherein the second direction is either clockwise or counterclockwise, and the first direction and the second direction are different.

[0022] Optionally, the above processing module can be an optical coupler.

[0023] By introducing a processing module, when a ring network fails, the optical carrier is transmitted in both clockwise and counterclockwise directions on the ring network, so that all RRHs on the ring network can receive the optical carrier, thus assisting in the self-healing function.

[0024] Secondly, embodiments of this application provide a CO device, including a microwave photon generation module, a modulation module, a multiplexing module, a first optical circulator, a first optical switch, a demultiplexing module, and a receiving array.

[0025] Among them, the microwave photon generation module is connected to the multiplexing module through the modulation module, the multiplexing module is connected to the first port of the first optical circulator, the second port of the first optical circulator is connected to the first port of the first optical switch, the third port of the first optical circulator is connected to the receiving array through the demultiplexing module, and the second or third port of the first optical switch is the input / output port of the CO device.

[0026] A microwave photon generation module is used to generate N first optical carriers and transmit the N first optical carriers to a modulation module; the wavelengths of the N first optical carriers are all different; N is an integer greater than 0;

[0027] The modulation module is used to modulate the baseband signal onto N first optical carriers to obtain N second optical carriers, and transmit the N second optical carriers to the multiplexing module. Each of the N second optical carriers carries the baseband signal.

[0028] The multiplexing module is used to converge N second optical carrier signals onto a single optical path, input them to the first port of the first optical circulator, and input them from the second port of the first optical circulator to the first port of the first optical switch, and then output them through the second or third port of the first optical switch.

[0029] The demultiplexing module is used to demultiplex the third optical carrier and transmit the demultiplexed optical carrier to the receiving array. The third optical carrier is input through the second or third port of the first optical switch, passes through the first port of the first optical switch, is input from the second port of the first optical circulator, and is output from the third port of the first optical circulator to the demultiplexing module.

[0030] Optionally, the aforementioned power divider module can be an optical power divider, an optical coupler, or other device that can split an optical signal into two.

[0031] By using all-optical devices to construct CO equipment, the electrical noise and interference caused by using electrical mixers can also be avoided.

[0032] In one feasible embodiment, the CO device further includes a monitoring module connected to the control port of the first optical switch;

[0033] The monitoring module is configured to, if no optical signal is detected on the first optical switch when the first and second ports of the first optical switch are connected and the first and third ports of the first optical switch are disconnected, control the first and second ports of the first optical switch to disconnect and connect them, so that N second carriers are output through the third port of the first optical switch; or, if no optical signal is detected when the first and second ports of the first optical switch are disconnected and the first and third ports of the first optical switch are connected, control the first and second ports of the first optical switch to connect and disconnect them, so that N second carriers are output through the second port of the first optical switch.

[0034] The first monitoring module detects whether there is an optical signal passing through the first optical switch, thereby determining whether the optical fiber connected to the second or third port is working properly; if any one of the optical fibers fails, it switches to the other optical fiber to work, thereby realizing the network's self-healing function.

[0035] Optionally, the multiplexing module is an arrayed waveguide grating (AWG).

[0036] In one feasible embodiment, the modulation module includes N modulators, and the i-th modulator among the N modulators is used to modulate the baseband signal onto the i-th first optical carrier among the N first optical carriers to obtain the i-th second optical carrier among the N second optical carriers; where i = 1, 2, 3, ..., N.

[0037] Thirdly, embodiments of this application provide an RRH, including: a wavelength selection circuit, a signal processing circuit, and a transmitting and receiving circuit.

[0038] The first and second ports of the wavelength selection circuit are respectively the first and second ports of the RRH, the third and fourth ports of the wavelength selection circuit are respectively connected to the first and second ports of the signal processing circuit, and the third port of the signal processing circuit is connected to the input and output ports of the transmitting and receiving circuit.

[0039] A wavelength selection circuit is used to obtain a target optical carrier from the second optical carrier received at port 1, and output the optical carriers other than the target optical carrier from the received second optical carrier at port 2. Port 1 is either the first port or the second port of the wavelength selection circuit, and port 2 is either the first port or the second port of the wavelength selection circuit. Port 1 and port 2 are not the same.

[0040] The signal processing circuit is used to split the optical carrier input from the first port into a first target optical carrier and a second target optical carrier, convert the first target optical carrier into an electrical signal and transmit it to the transmitting and receiving circuit; erase the baseband signal in the second target optical carrier to obtain a seed optical signal, and modulate the uplink signal received by the transmitting and receiving circuit onto the seed optical carrier to obtain a third optical carrier; and output the signal through the second port of the signal processing circuit to the wavelength selection circuit.

[0041] Transmitting and receiving circuits are used to transmit electrical signals obtained from the signal processing circuit; and to receive uplink signals.

[0042] A wavelength selection circuit is used to output the received third optical carrier through port 1.

[0043] By erasing the baseband signal carried in the first target optical carrier, a seed optical signal is obtained; and the uplink signal is modulated onto the seed optical signal. Since the wavelength of the seed optical signal is the same as the wavelength of the first optical carrier, frequency synchronization of the uplink and downlink optical carriers is achieved by using the same light source, thus avoiding the electrical noise and interference caused by the use of electrical mixers.

[0044] In one feasible embodiment, the wavelength selection circuit includes a second optical circulator, a first wavelength selection control module, a second wavelength selection control module, and a second optical switch.

[0045] The first and third ports of the second optical circulator are respectively the first and second ports of the wavelength selection circuit. The second and fourth ports of the second optical circulator are respectively connected to the first and second ports of the second optical switch through the first and second wavelength selection control modules. The third and fourth ports of the second optical switch are respectively the third and fourth ports of the wavelength selection circuit.

[0046] When the second optical carrier is input from the first port of the second optical circulator and output to the first wavelength selection control module through the second port of the second optical circulator,

[0047] The first wavelength selection control module is used to obtain the target optical carrier from the received second optical carrier, output the target optical carrier to the first port of the second optical switch, and then output it from the third port of the second optical switch; and output the optical carriers other than the target optical carrier from the received second optical carrier to the second port of the second optical circulator, and then output them from the third port of the second optical circulator.

[0048] The second optical circulator is used to output the third optical carrier, which is input from the fourth port and the second port of the second optical switch and input to the fourth port of the second optical circulator via the second wavelength selection module, from the fourth port of the second optical circulator.

[0049] When the second optical carrier is input from the third port of the second optical circulator and output to the second wavelength selection control module through the fourth port of the second optical circulator,

[0050] The second wavelength selection control module is used to obtain the target optical carrier from the received second optical carrier, output the target optical carrier to the second port of the second optical switch, and then output it from the third port of the second optical switch; and output the optical carriers other than the target optical carrier from the received second optical carrier to the fourth port of the second optical circulator, and output them from the first port of the second optical circulator.

[0051] The second optical circulator is used to output the third optical carrier, which is input from the fourth port and the first port of the second optical switch and then input to the second port of the second optical circulator via the first wavelength selection module, from the third port of the second optical circulator.

[0052] By introducing optical devices, the electrical noise and interference caused by using electrical mixers are avoided, thus avoiding the need for costly correction schemes when using electrical mixers.

[0053] In one feasible embodiment, the wavelength selection circuit further includes a second monitoring module, which is connected to the control terminal of the second optical switch.

[0054] The second monitoring module is used to detect whether there is an optical signal passing through the second optical switch, and to control the connection and disconnection between the ports of the second optical switch according to the detection result;

[0055] If no optical signal is detected when the first and third ports of the second optical switch are connected and the second and fourth ports are connected, the first and fourth ports of the second optical switch are connected and the second and third ports are connected.

[0056] The on / off state of each port of the switch is controlled by detecting whether there is a light signal passing through the second optical switch, thereby enabling normal input and output of light signals.

[0057] In one feasible embodiment, the wavelength selection circuit further includes: a configuration module, wherein a first port of the configuration module is connected to a second port of the second optical circulator, and the second port of the configuration module is connected to a first wavelength selection control module and a second wavelength selection control module;

[0058] The configuration module is used to obtain a common optical carrier from the optical carrier output from the second port of the second optical circulator, and to parse wavelength selection information from the common optical carrier; and to transmit the wavelength selection information to the first wavelength selection control module and the second wavelength selection control module, so that the first wavelength selection control module or the second wavelength selection control module obtains the target optical carrier from the received second optical carrier according to the wavelength selection information.

[0059] By introducing wavelength selection information, it is possible to ensure that different RRHs select different wavelength optical carriers, thereby achieving automatic management of RRH wavelength selection.

[0060] In one feasible embodiment, the wavelength of the target optical carrier is the same as the wavelength of the optical carrier required for the RRH.

[0061] In one feasible embodiment, the signal processing circuitry includes: a power divider module, a reflective semiconductor optical amplifier (RSOA), a low-noise amplifier (LNA), a photodiode (PD), and an optical isolator.

[0062] In this circuit, the input port of the power divider module and the inverting terminal of the optical isolator are the first and second ports of the signal processing circuit, respectively. The first output port of the power divider module is connected to the first port of the RSOA, the second output port of the power divider module is connected to the first port of the PD, the second port of the RSOA is connected to the first port of the LNA, the third port of the RSOA is connected to the non-inverting terminal of the optical isolator, and the second ports of the LNA and the PD constitute the third port of the signal processing circuit.

[0063] The power splitter module is used to split the target optical carrier input from its input port into a first target optical carrier and a second target optical carrier, and output the first target optical carrier and the second target optical carrier to RSOA and PD respectively through the first output port and the second output port;

[0064] The PD is used to convert the second target optical carrier into an electrical signal and output it from the second port of the PD.

[0065] The RSOA is used to erase the baseband signal carried in the first target optical carrier to obtain the seed optical signal; and modulate the uplink signal input from the second port of the RSOA onto the seed optical signal to obtain the third optical carrier, which is then output through the optical isolator.

[0066] The uplink signal is transmitted from the second port of the LNA through its first port to the second port of the RSOA.

[0067] Fourthly, embodiments of this application provide a communication method applied to a communication system, the communication system including multiple RRHs, including:

[0068] The baseband signal is modulated onto N generated first optical carriers to obtain N second optical carriers, wherein the wavelengths of the N first optical carriers are different and N is an integer greater than 0; the target optical carrier is obtained from the second optical carriers received by any RRH among the multiple RRHs, the target optical carrier is converted into an electrical signal, and the electrical signal is transmitted as a downlink signal.

[0069] In one feasible embodiment, the method of this implementation further includes:

[0070] The seed optical signal is obtained based on the target optical carrier; the received uplink signal is modulated onto the seed optical signal to obtain the third optical carrier.

[0071] In one feasible embodiment, the wavelength of the target optical carrier acquired by any RRH is the same as the wavelength of the optical carrier required by any RRH, or the target optical carrier acquired by any RRH is obtained from the received second optical carrier according to wavelength selection information.

[0072] In one feasible embodiment, the communication system further includes a CO device, which is connected to a ring network composed of multiple RRHs via optical fibers through a first optical fiber and a second optical fiber. The method of this embodiment includes:

[0073] When a fault is detected in the first optical fiber, the optical carrier is transmitted between the CO device and the ring network via the second optical fiber.

[0074] In one feasible embodiment, the method further includes:

[0075] When a fiber optic failure occurs between two adjacent RRHs in a ring network, N second optical carriers are controlled to transmit in the ring network along a first direction and a second direction, wherein the first direction and the second direction are not the same.

[0076] Fifthly, embodiments of this application provide a communication method, including:

[0077] The baseband signal is modulated onto N generated first optical carriers to obtain N second optical carriers. The wavelengths of the N first optical carriers are all different, and N is an integer greater than 0. The N second optical carriers are multiplexed onto a single optical path and output through the first optical fiber.

[0078] In one feasible embodiment, the method of this embodiment further includes:

[0079] The third optical carrier is obtained through the first optical fiber, and the third optical carrier carries the uplink signal; the third optical carrier is demultiplexed.

[0080] In one feasible embodiment, the method of this embodiment further includes:

[0081] When a fault is detected in the first fiber, the system switches to the second fiber for optical carrier transmission.

[0082] Sixthly, embodiments of this application provide a communication method, including:

[0083] The target optical carrier is obtained from the received second optical carrier, and the first target optical carrier and the second target optical carrier are obtained based on the target optical carrier. Both the first target optical carrier and the second target optical carrier carry baseband signals. The first target optical carrier is converted into an electrical signal and transmitted as a downlink signal. The baseband signal in the second target optical carrier is erased to obtain a seed optical signal. The received uplink signal is modulated onto the seed optical signal to obtain a third optical carrier.

[0084] In one feasible embodiment, the wavelength of the target optical carrier is the same as the wavelength of the optical carrier required for the RRH.

[0085] In one feasible embodiment, obtaining the target optical carrier from the received second optical carrier includes:

[0086] The target optical carrier is obtained from the received second optical carrier based on the wavelength selection information.

[0087] In a seventh aspect, embodiments of this application provide a computer storage medium including computer instructions that, when executed on an electronic device, cause the electronic device to perform part or all of the methods described in the fourth, fifth, or sixth aspects.

[0088] Eighthly, embodiments of this application provide a computer program product that, when run on a computer, causes the computer to perform part or all of the methods described in the fourth, fifth, or sixth aspects.

[0089] The proposed solution firstly achieves a re-segmentation of distributed base station functions. Compared to the existing BBU and RRU architecture, the baseband signal processing function of the BBU and the baseband signal mixing function of the RRU are moved to the CO equipment side for processing. The RRH retains only a few functions, such as signal transmission and reception, achieving high bandwidth, low cost, and low power consumption, while also achieving fault self-healing and solving the problem of fiber optic faults. Secondly, the CO equipment and RRH are implemented based on optical devices, eliminating the dependence on high-performance electrical devices in traditional base stations. Finally, the RSOA in the RRH erases the baseband signal carried in the first target optical carrier to obtain the seed optical signal and modulates the uplink signal onto the seed optical signal. Since the wavelength of the seed optical signal is the same as the wavelength of the first optical carrier, frequency synchronization of the uplink and downlink optical carriers is achieved using the same light source, avoiding the electrical noise and interference caused by the use of electrical mixers, and thus avoiding the costly correction scheme required by using electrical mixers.

[0090] These or other aspects of this application will become more apparent in the following description of the embodiments. Attached Figure Description

[0091] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0092] Figure 1 This is a schematic diagram of the structure of a distributed base station in the prior art;

[0093] Figure 2 This application provides a schematic diagram of the structure of a communication system according to an embodiment of the present application.

[0094] Figure 3 A schematic diagram illustrating the working principle of the CO device in the event of a fiber optic failure between the device and the ring network;

[0095] Figure 4 This is a schematic diagram illustrating the working principle of a ring network in the event of a fiber optic failure.

[0096] Figure 5 This is a schematic diagram of the structure of a CO device provided in an embodiment of this application;

[0097] Figure 6 A schematic diagram of an RRH structure provided in an embodiment of this application;

[0098] Figure 7 This is a schematic diagram of another RRH structure provided in an embodiment of this application;

[0099] Figure 8 This is a schematic diagram of another RRH structure provided in an embodiment of this application;

[0100] Figure 9 This is an interactive flowchart illustrating a communication method provided in an embodiment of this application. Detailed Implementation

[0101] The embodiments of this application will now be described with reference to the accompanying drawings.

[0102] See Figure 2 , Figure 2 This is a schematic diagram of the structure of a communication system provided in an embodiment of this application. Figure 2 As shown, the distributed base station includes a CO device 100 and N RRH 200s, where N is an integer greater than 1. The N RRH 200s are connected end to end by optical fibers to form a ring network. The CO device 100 is connected to the ring network through at least two optical fibers. Optionally, the at least two optical fibers include a first optical fiber and a second optical fiber.

[0103] CO device 100 generates N first optical carriers, each with a different wavelength, and modulates the baseband signal onto these N first optical carriers to obtain N second optical carriers, such as... Figure 2 As shown, the N second optical carriers are represented as: λ1,…,λ N CO device 100 transmits N second optical carriers to the ring network through the first optical fiber; the N second optical carriers are transmitted along the first direction on the ring network, optionally, the first direction is clockwise or counterclockwise; each of the N RRH 200s obtains its corresponding target optical carrier from the received second optical carriers, and transmits the second optical carriers excluding the target optical carrier back to the ring network.

[0104] Optionally, the wavelength of the target optical carrier acquired by RRH is the same as the wavelength of the optical carrier required by RRH.

[0105] like Figure 2 As shown, for RRH1 in N RRH 200, from the second optical carrier λ1,…,λ N Select the second optical carrier λ1 as the target optical carrier corresponding to RRH1, and transmit the second optical carrier to λ2,…,λ N Return to the ring network so that it continues to propagate along the first direction within the ring network; for N RRHs... k From the second optical carrier λ k ,…,λ N Select the second optical carrier as λ k For RRH k The corresponding target optical carrier, and transmit the second optical carrier λk+1 ,…,λ N The data is transmitted back to the ring network and continues to be transmitted in the ring network along the first direction, which is counterclockwise.

[0106] For example, suppose the CO device outputs optical carrier A and optical carrier B with wavelength ratios of X and Y; the wavelength of the optical carrier required by RRHA in the ring network is X, and the wavelength of the optical carrier required by RRHB is Y; then the target optical carrier of RRHA is optical carrier A, and the target optical carrier of RRHB is optical carrier B.

[0107] In one feasible embodiment, while generating N first optical carriers, the CO device 100 also generates a common optical carrier for carrying wavelength selection information. The CO device 100 transmits the common optical carrier and N second optical carriers to the processing module 300 through a first optical fiber or a second optical fiber. The processing module transmits the common optical carrier and N second optical carriers together to the ring network and controls the common optical carrier and N second optical carriers to transmit along a first direction in the ring network.

[0108] After receiving the common optical carrier and the second optical carrier, each of the N RRH 200s parses the wavelength selection information from the common optical carrier. Based on the wavelength selection information, the RRH 200 obtains the target optical carrier from the received second optical carrier. After obtaining the target optical carrier, the RRH 200 transmits the common optical carrier and the second optical carriers received (excluding the target optical carrier) back to the ring network.

[0109] Each of the N RRH 200s converts the corresponding target optical carrier into an electrical signal and transmits the electrical signal as a downlink signal; each RRH 200 receives the uplink signal and modulates the uplink signal onto a seed optical signal obtained based on the target optical carrier to obtain an uplink optical carrier; the uplink optical carrier is transmitted along the second direction in the ring network and transmitted to the CO device 100 through the first optical fiber, wherein the seed optical signal is obtained based on the target optical carrier.

[0110] like Figure 2 As shown, for N RRHs, RRH N After obtaining the uplink optical carrier λ N After that, the uplink optical carrier λ N Transmitted into the ring network, along the second direction; for N RRHs, RRHs... k After obtaining the uplink optical carrier λ k After that, the uplink optical carrier λ k The data is transmitted to the ring network, along the second direction, and finally to CO device 100. The first and second directions are not the same.

[0111] like Figure 3 As shown, when the CO device 100 detects a fault in the first optical fiber, the CO device 100 transmits N second optical carriers to the ring network through the second optical fiber.

[0112] In one feasible embodiment, the communication system further includes a processing module 300, which is connected between the CO device 100 and the ring network, and the processing module 300 is connected to the CO device 100 via the aforementioned at least two optical fibers;

[0113] When the processing module 300 detects a fiber optic fault in the ring network, it controls N second optical carriers to transmit along a first direction and a second direction on the ring network. The first direction is either clockwise or counterclockwise, and the second direction is either counterclockwise or clockwise, and the first and second directions are not the same. Each of the N RRH200s acquires its corresponding target optical carrier in the above manner and performs subsequent processing.

[0114] like Figure 4 As shown, RRHs out of N RRHs k-1 and RRH k In the event of a fiber optic fault, the processing module 300 controls N second optical carriers λ1,…,λ N Transmitted along the first direction and the second direction on the ring network respectively; the first direction is counterclockwise and the second direction is clockwise; for RRH1 and RRH k-1 For each of the RRHs in the first direction, the second optical carrier transmitted from the first direction is input from the first port of that RRH. The RRH obtains the target optical carrier corresponding to that RRH from the received second optical carrier and transmits the obtained uplink optical carrier along the second direction, and transmits it to the CO device 100 through the processing module 300 and the first optical fiber; for each RRH... k With RRH N In each of the RRHs and the RRHs between them, the second optical carrier transmitted from the second direction is input from the second port of the RRH. The RRH obtains the target optical carrier corresponding to the RRH from the received second optical carrier, and transmits the obtained uplink optical carrier along the first direction, and transmits it to the CO device 100 through the processing module 300 and the first optical fiber.

[0115] Optionally, the processing module 300 can be an optical coupler.

[0116] In one feasible embodiment, any two adjacent RRHs among multiple RRHs can be connected by one optical fiber, two optical fibers, or even more than two optical fibers to achieve bidirectional transmission of uplink and downlink signals. Connecting with two optical fibers can avoid interference between uplink and downlink optical signals.

[0117] The specific structure and working principle of CO device 100 are described below.

[0118] like Figure 5 As shown, the CO device 100 includes a microwave photon generation module 101, a modulation module 102, a multiplexing module 103, a first optical circulator 104, a first optical switch 105, a demultiplexing module 106, and a receiving array 107.

[0119] The microwave photon generation module 101 is connected to the multiplexing module 103 via the modulation module 102. The multiplexing module 103 is connected to the first port of the first optical circulator 104. The second port of the first optical circulator 104 is connected to the input port of the first optical switch 105. The third port of the first optical circulator 104 is connected to the receiving array 107 via the demultiplexing module 106. When an optical carrier is input from the first port of the first optical circulator 104, the optical carrier is output from the second port of the first optical circulator 104. The second or third port of the first optical switch 105 is the output port of the CO device 100. The second port of the first optical switch 105 is connected to one end of the first optical fiber, and the third port of the first optical switch 105 is connected to one end of the second optical fiber. When an optical carrier is input from the second port of the first optical circulator 104, the optical carrier is output from the third port of the first optical circulator 104.

[0120] The microwave photon generation module 101 is used to generate N first optical carriers, each of which has a different wavelength; N is an integer greater than 1.

[0121] The modulation module 102 is used to modulate the baseband signal onto N first optical carriers to obtain N second optical carriers, each of the N second optical carriers carrying the aforementioned baseband signal; optionally, the modulation module 102 includes N modulators, and for the i-th modulator among the N modulators, the input baseband signal is modulated onto the i-th first optical carrier among the N optical carrier signals to obtain the i-th second optical carrier, i = 1, 2, ..., N;

[0122] The multiplexing module 103 is used to converge N second optical carriers onto a single optical path, input them to the first port of the first optical circulator 104, and output them from the second port of the first optical circulator 104 to the first port of the first optical switch 105.

[0123] The first port and the second port of the first optical switch 105 are connected, and N second optical carriers are output from the second port of the first optical switch 105 and then output to the processing module 300 through the first optical fiber.

[0124] The demultiplexing module 106 is used to demultiplex the third optical carrier and transmit the demultiplexed optical carrier to the receiving array 107. The third optical carrier is input from the second port of the first optical switch 105, passes through the first port of the first optical switch 105, and is input from the second port of the first optical circulator 104 and output from the third port of the first optical circulator 104 to the demultiplexing module 106.

[0125] Among them, the first optical switch 105 can be a 1*2 optical switch, the multiplexing module 103 can be a 1*N multiplexing device, such as an AWG device, and the demultiplexing module 106 can be a 1*N demultiplexer.

[0126] It should be noted that the N first optical carriers generated by the microwave photonics generation module 101 contain radio frequency signals. The modulation module 102 modulates the baseband signal onto the N first optical carriers to obtain N second optical carriers. Specifically, the modulation module 102 modulates the baseband signal onto the radio frequency signals of the N first optical carriers to obtain N second optical carriers.

[0127] Optionally, the CO device 100 also generates a common optical carrier for carrying wavelength selection information, which is transmitted to the ring network together with N second optical carriers.

[0128] Optionally, the CO device 100 also includes a first monitoring module 108, which is connected to the control port of the first optical switch 105;

[0129] The first monitoring module 108 is used to detect whether there is an optical signal between the first port and the second port of the first optical switch 105, or between the second port and the third port of the first optical switch 105, and to control the first port and the second port or the third port of the first optical switch 105 to be connected or disconnected according to the detection result.

[0130] If no optical signal is detected when the first port and the second port of the first optical switch 105 are connected and the first port and the third port of the first optical switch 105 are disconnected, then it is determined that the optical fiber connected to the second port of the first optical switch 105 is faulty, and the first port and the second port of the first optical switch 105 are disconnected, and the first port and the third port of the first optical switch 105 are connected.

[0131] If no optical signal is detected when the first port and the third port of the first optical switch 105 are connected and the first port and the second port of the first optical switch 105 are disconnected, then the optical fiber connected to the third port of the first optical switch 105 is determined to be faulty. The first port and the second port of the first optical switch 105 are then connected, and the first port and the third port of the first optical switch 105 are then disconnected.

[0132] like Figure 3 As shown, when the first port and the second port of the first optical switch 105 are connected and the first port and the third port are disconnected, the CO device 100 and the processing module 300 transmit optical signals through the first optical fiber. When the first optical fiber fails, the first monitoring module 108 does not detect an optical signal between the first port and the second port of the first optical switch 105. The first monitoring module 108 controls the first port and the third port of the first optical switch 105 to be connected and the first port and the second port to be disconnected, so that the CO device 100 and the processing module 300 transmit optical signals through the second optical fiber.

[0133] The monitoring module detects whether there is an optical signal passing through the first optical switch 105 to determine whether the optical fiber connected to the first optical switch 105 is faulty. When a fault is detected, the optical switch is controlled to switch the path, thereby realizing the system's self-healing function.

[0134] Redundant fiber optic protection is used between the CO device 100 and the processing module 300, such as Figure 3 As shown, when the first optical fiber malfunctions, the first monitoring module 108 of the CO device 100 monitors whether the optical power on the first optical switch 105 is abnormal. The first monitoring module 108 of the CO device 100 determines whether there is an abnormality in the optical fiber's transmission by listening to whether the optical power on the first optical switch 105 is abnormal. Once an abnormality is detected, the first optical switch 105 will be triggered to automatically switch to the second optical fiber for normal transmission. An abnormality refers to a fault in the corresponding optical fiber causing an abnormality in the optical path, resulting in abnormal transmission and reception at the remote RRH.

[0135] The specific structure and working principle of RRH are described below.

[0136] Each of the above N RRHs includes: a wavelength selection circuit 21, a signal processing circuit 22, and a transmitting and receiving circuit 23. The first port and the second port of the wavelength selection circuit 21 are the first port and the second port of the RRH, respectively. The third port and the fourth port of the wavelength selection circuit 21 are connected to the first port and the second port of the signal processing circuit 22, respectively. The third port of the signal processing circuit 22 is connected to the input and output ports of the transmitting and receiving circuit 23.

[0137] Wavelength selection circuit 21 is used to obtain the target optical carrier from the second optical carrier received from port 1, and output the optical carrier other than the target optical carrier from the received second optical carrier from port 2. Port 1 is the first port or the second port of wavelength selection circuit 21, and port 2 is the first port or the second port of wavelength selection circuit 21. Port 1 and port 2 are not the same.

[0138] Signal processing circuit 22 is used to split the optical carrier input from the first port into a first target optical carrier and a second target optical carrier, convert the first target optical carrier into an electrical signal and transmit it to the transmitting and receiving circuit 23; erase the baseband signal in the second target optical carrier to obtain a seed optical signal, and modulate the uplink signal received by the transmitting and receiving circuit 23 onto the seed optical carrier to obtain a third optical carrier; and output it to wavelength selection circuit 21 through the second port of signal processing circuit 22.

[0139] Transmitter / receiver circuit 23 is used to transmit the electrical signal obtained by signal processing circuit 22 and to receive uplink signals.

[0140] Wavelength selection circuit 21 is used to output the received third optical carrier through port 1.

[0141] In one feasible embodiment, such as Figure 6 As shown, the wavelength selection circuit 21 includes a second optical circulator 201, a first wavelength selection control module 202, a second wavelength selection control module 203, and a second optical switch 204.

[0142] The first and third ports of the second optical circulator 201 are the first and second ports of the wavelength selection circuit 21, respectively. The second and fourth ports of the second optical circulator 201 are connected to the first and second ports of the second optical switch 204 through the first wavelength selection control module 202 and the second wavelength selection control module 203, respectively. The third and fourth ports of the second optical switch 204 are the third and fourth ports of the wavelength selection circuit 21, respectively.

[0143] When the second optical carrier is input from the first port of the second optical circulator 201 and output to the first wavelength selection control module 202 through the second port of the second optical circulator 201,

[0144] The first wavelength selection control module 202 is used to obtain the target optical carrier from the received second optical carrier, output the target optical carrier to the first port of the second optical switch 204, and then output it from the third port of the second optical switch 204; and output the optical carriers other than the target optical carrier from the received second optical carrier to the second port of the second optical circulator 201, and output them from the third port of the second optical circulator 201.

[0145] The second optical circulator 201 is used to output the third optical carrier, which is input from the fourth port and the second port of the second optical switch 204 and input to the fourth port of the second optical circulator 201 via the second wavelength selection module, from the first port of the second optical circulator 201.

[0146] When the second optical carrier is input from the third port of the second optical circulator 201 and output to the second wavelength selection control module 203 through the fourth port of the second optical circulator 201,

[0147] The second wavelength selection control module 203 is used to obtain the target optical carrier from the received second optical carrier, output the target optical carrier to the second port of the second optical switch 204, and then output it from the third port of the second optical switch 204; and output the optical carriers other than the target optical carrier from the received second optical carrier to the fourth port of the second optical circulator 201, and output them from the first port of the second optical circulator 201.

[0148] The second optical circulator 201 is used to output the third optical carrier, which is input from the fourth port and the first port of the second optical switch 204 and input to the second port of the second optical circulator 201 via the first wavelength selection module, from the third port of the second optical circulator 201.

[0149] In one feasible embodiment, such as Figure 7 As shown, the wavelength selection circuit 21 also includes a second monitoring module 213, which is connected to the control terminal of the second optical switch 204.

[0150] The second monitoring module 213 is used to detect whether there is an optical signal passing through the second optical switch 204, and to control the connection and disconnection between the ports of the second optical switch 204 according to the detection result;

[0151] If no optical signal is detected when the first port and the third port of the second optical switch 204 are connected and the second port and the fourth port are connected, the first port and the fourth port of the second optical switch 204 are connected and the second port and the third port are connected; if no optical signal is detected when the first port and the fourth port of the second optical switch 204 are connected and the second port and the third port are connected, the first port and the third port of the second optical switch 204 are connected and the second port and the fourth port are connected.

[0152] In one feasible embodiment, such as Figure 8 As shown, the wavelength selection circuit 21 further includes: a configuration module 214, the first port of the configuration module 214 is connected to the second port of the second optical circulator 201, and the second port of the configuration module 214 is connected to the first wavelength selection control module 202 and the second wavelength selection control module 203.

[0153] The configuration module 214 is used to obtain a common optical carrier from the optical carrier output from the second port of the second optical circulator 201, and to parse wavelength selection information from the common optical carrier; and to transmit the wavelength selection information to the first wavelength selection control module 202 and the second wavelength selection control module 203, so that the first wavelength selection control module 202 or the second wavelength selection control module 203 obtains the target optical carrier from the received second optical carrier according to the wavelength selection information.

[0154] In one feasible embodiment, the wavelength of the target optical carrier is the same as the wavelength of the optical carrier required for the RRH.

[0155] In one feasible embodiment, such as Figure 6 As shown, the signal processing circuit 22 includes: a power divider module 205, an RSOA 206, an LNA 208, a PD 207, and an optical isolator 210.

[0156] In this circuit, the input port of the power divider module 205 and the inverting terminal of the optical isolator 210 are the first and second ports of the signal processing circuit 22, respectively. The first output port of the power divider module 205 is connected to the first port of the RSOA 206, the second output port of the power divider module 205 is connected to the first port of the PD 207, the second port of the RSOA 206 is connected to the first port of the LNA 208, the third port of the RSOA 206 is connected to the non-inverting terminal of the optical isolator 210, and the second ports of the LNA and the PD 207 constitute the third port of the signal processing circuit 22.

[0157] The power splitter module 205 is used to split the target optical carrier input from its input port into a first target optical carrier and a second target optical carrier, and output the first target optical carrier and the second target optical carrier to RSOA 206 and PD 207 respectively through the first output port and the second output port;

[0158] PD 207 is used to convert the second target optical carrier into an electrical signal and output it from the second port of PD 207;

[0159] RSOA 206 is used to erase the baseband signal carried in the first target optical carrier to obtain a seed optical signal; and to modulate the uplink signal input from the second port of RSOA 206 onto the seed optical signal to obtain a third optical carrier, which is then output through optical isolator 210.

[0160] The uplink signal is transmitted from the second port of LNA 208 through its first port to the second port of RSOA 206.

[0161] It should be noted that the power divider module 205 divides the target optical carrier into a first target optical carrier and a second target optical carrier according to a preset division ratio in terms of power; the power ratio of the first target optical carrier to the power of the second target optical carrier is the preset division ratio mentioned above.

[0162] The transmitting and receiving circuit 23 includes a duplexer 209 and an antenna 211. The electrical signal converted from the first target optical carrier is transmitted through the duplexer 209 and then through the antenna 211. The uplink signal is input to the signal processing circuit 22 through the antenna 211 and the duplexer 209.

[0163] The following is an overview of the structure and functions of the RRH 200.

[0164] like Figure 6 As shown, each of the above N RRHs includes: a second optical circulator 201, a first wavelength selection control module 202, a second wavelength selection control module 203, a second optical switch 204, a power divider module 205, a ROSA 206, a PD 207, an LNA 208, a duplexer 209, an optical isolator 210, and an antenna 211;

[0165] Specifically, the first and third ports of the second optical circulator 201 are respectively the first and second ports of the aforementioned RRH. The second and fourth ports of the second optical circulator 201 are connected to the first and second ports of the second optical switch 204 via the first wavelength selection control module 202 and the second wavelength selection control module 203, respectively. The third port of the second optical switch 204 is connected to the input port of the power divider module 205. The first output port of the power divider module 205 is connected to the first port of the RSOA 206. The second output port of the power divider module 205 is connected to the duplexer 209 via the PD 207. The second port of the RSOA 206 is connected to the duplexer via the LNA 208. The third port of the RSOA 206 is connected to the forward end of the optical isolator 210. The reverse end of the optical isolator 210 is connected to the fourth port of the second optical switch 204. The duplexer 209 is connected to the antenna 211.

[0166] Among them, the second optical switch 204 is a 2*2 optical switch.

[0167] Optionally, the power divider module 205 can be an optical power divider, an optical coupler, or other device that has the function of splitting an optical signal into two.

[0168] It should be noted that the second optical circulator 201 serves as a routing module. An optical circulator is one method of implementing routing; other devices can also be used. Uplink and downlink connections in a ring network can be achieved via shared fiber or non-shared fiber connections; the difference lies only in the connection method of the routing modules.

[0169] In a feasible embodiment, when the second optical carrier is input from the first port of the RRH (i.e., the first port of the second optical circulator 201 of the RRH) and output to the first wavelength selection control module 202 through the second port of the second optical circulator 201 of the RRH, the first wavelength selection control module 202 obtains the target optical carrier from the received second optical carrier, outputs the target optical carrier to the first port of the second optical switch 204, and outputs the optical carriers other than the target optical carrier from the received second optical carrier to the second port of the second optical circulator 201, and then outputs them from the third port of the second optical circulator 201 to the downstream RRH of the RRH;

[0170] The first port and the third port of the second optical switch 204 are connected, and the second port and the fourth port are connected. The target optical carrier is output from the third port of the second optical switch 204 to the input port of the power divider module 205.

[0171] The power splitter module 205 is used to split the target optical carrier input from its input port into a first optical carrier and a second optical carrier, and output the first target optical carrier and the second target optical carrier to the first port of RSOA 206 and PD207 respectively through the first output port and the second output port;

[0172] PD 207 is used to convert the second target optical carrier into an electrical signal and transmit the electrical signal through duplexer 209 and antenna 211; wherein, the power of the first target optical carrier and the second target optical carrier may be the same or different;

[0173] RSOA 206 is used to erase the baseband signal carried in the first optical carrier to obtain a seed optical signal; modulate the uplink signal from antenna 211, duplexer 209 and LNA 208 onto the seed optical signal to obtain a third optical carrier; and transmit the third optical carrier to the fourth port of the second optical circulator 201 through optical isolator 210, the fourth port and the second port of the second optical switch 204 and the second wavelength selection control module 203, and output it from the first port of the second optical circulator 201.

[0174] In a feasible embodiment, when the second optical carrier is input from the third port of the RRH (i.e., the second port of the second optical circulator 201 of the RRH) and output to the second wavelength selection control module 203 through the fourth port of the second optical circulator 201 of the RRH, the second wavelength selection control module 203 obtains the target optical carrier from the received second optical carrier, outputs the target optical carrier to the first port of the second optical switch 204, and outputs the optical carriers other than the target optical carrier from the received second optical carrier to the second port of the second optical circulator 201, and then outputs them from the third port of the second optical circulator 201 to the downstream RRH of the RRH;

[0175] The first port and the fourth port of the second optical switch 204 are connected, and the second port and the third port are connected. The target optical carrier is output from the third port of the second optical switch 204 to the input port of the power divider module 205.

[0176] The power splitter module 205 is used to split the target optical carrier input from its input port into a first optical carrier and a second optical carrier, and output the first target optical carrier and the second target optical carrier to the first port of RSOA 206 and PD 207 respectively through the first output port and the second output port;

[0177] PD 207 is used to convert the second target optical carrier into an electrical signal and send the electrical signal through duplexer 209 and antenna 211; wherein, the power of the first target optical carrier and the second target optical carrier may be the same or different;

[0178] RSOA 206 is used to erase the baseband signal carried in the first target wave to obtain a seed optical signal; the uplink signal from antenna 211, duplexer 209 and LNA 208 is modulated onto the seed optical signal to obtain a third optical carrier; the third optical carrier is transmitted to the second port of the second optical circulator 201 through the optical isolator, the fourth port and the first port of the second optical switch 204 and the first wavelength selection control module 202, and output from the third port of the second optical circulator 201.

[0179] It should be noted that RSOA 206 operates in the saturation region. When operating in the saturation region, RSOA 206 erases the baseband signal in the first target optical carrier to obtain the seed optical signal.

[0180] Optionally, the RRH also includes a power amplifier (PA) 212. The input port of PA 212 is connected to the output port of PD 207, and the output port of PA 212 is connected to a duplexer 209. PA 212 amplifies the electrical signal output by PD 207 and transmits it to antenna 211 for transmission through duplexer 209, thus avoiding the problem that the power of the electrical signal output by PD 207 is too low to meet the transmission requirements.

[0181] Optionally, the RRH 200 also includes a second monitoring module 213, which is connected to the control port of the second optical switch 204.

[0182] The second monitoring module 213 is used to detect whether an optical signal passes through the second optical switch 204; if no optical signal is detected passing through the second optical switch 204 when the first port and the third port of the second optical switch 204 are connected and the second port and the fourth port are connected, then the second optical switch 204 is controlled to connect between the second port and the third port and between the first port and the fourth port; Figure 7 As shown;

[0183] If no optical signal is detected passing through the second optical switch 204 when the first and fourth ports are connected and the second and third ports are connected, then the first and third ports of the second optical switch 204 are connected, and the second and fourth ports are connected. Figure 6 As shown.

[0184] like Figure 6 As shown, the first and third ports of the second optical switch 204 are connected, and the second and fourth ports are also connected. The second monitoring module 213 does not detect any optical signal passing through the second optical switch 204. At this time, the second monitoring module 213 controls the first and fourth ports of the second optical switch 204 to be connected, and the second and fourth ports to be connected, as shown. Figure 7 As shown; the second optical carrier λ1,…,λ k The second wavelength selection control module 203 receives input from the third port of the second optical circulator 201 and outputs from the fourth port of the second optical circulator 201; the second wavelength selection control module 203 receives input from the second optical carrier λ1,…,λ k Select the target optical carrier λ k The second wavelength selection control module 203 outputs the second optical carrier λ1,…,λ through its first port. k-1 The second optical carrier λ1,…,λ k-1 The signal is input through the fourth port of the second optical circulator 201 and output through the third port to be transmitted to the next RRH;

[0185] Target optical carrier λ k The signal is transmitted through the second and third ports of the second optical switch 204 to the input port of the power divider module 205. The power divider module 205 splits the target optical carrier into a first target optical carrier and a second target optical carrier, and outputs them to RSOA 206 and PD 207 through the first and second output ports, respectively. PD 207 converts the second target optical carrier into an electrical signal and transmits it to antenna 211 for transmission through a duplexer. RSOA 206 operates in the saturation region. In the saturation region, RSOA 206 erases the baseband signal on the radio frequency signal of the first target optical carrier to obtain a seed optical signal. The uplink signal received by antenna 211 is input to LNA 208 through duplexer 209. LNA 208 amplifies the uplink signal, and RSOA 206 modulates the amplified uplink signal onto the radio frequency signal of the seed optical signal to obtain the third optical carrier λ. k ′, the third optical carrier λ k The output is through the third port of RSOA 206, and then through the optical isolator 210 to the fourth port of the second optical switch 204; after passing through the second optical switch 204 and the first wavelength selection control module 202, it is output to the second port of the second optical circulator 201, and then output from the third port of the second optical circulator 201.

[0186] Optionally, such as Figure 8 As shown, the above-mentioned RRH also includes a configuration module 214. The first port of the configuration module 214 is connected to the second port of the second optical circulator 201, and the second port of the configuration module 214 is connected to the control terminal of the first wavelength selection control module 202 and the control terminal of the second wavelength selection control module 203.

[0187] Configuration module 214 obtains a common optical carrier from the optical carrier output from the second port of the second optical circulator 201, and parses wavelength selection information from the common optical carrier; first wavelength selection control module 202 obtains a target optical carrier from the received second optical carrier according to the wavelength selection information, and second wavelength selection control module 203 obtains a target optical carrier from the received second optical carrier according to the wavelength selection information.

[0188] After the first wavelength selection and control module 202 in the RRH selects the target optical carrier, the configuration module 214 records the optical carrier selected by the RRH and ensures that different RRHs select different wavelength optical carriers, thereby realizing automatic management of RRH wavelength selection.

[0189] It should be noted that the second port of the second optical circulator 201 is connected to the configuration module 214 and the first wavelength selection control module 202 via a 1*2 optical switch. The input port of the optical switch is connected to the second port of the second optical circulator 201, and the first output port and the second output port of the optical switch are respectively connected to the configuration module 214 and the first wavelength selection control module 202. When the second port of the second optical circulator 201 outputs a common optical carrier, the input port and the first output port of the aforementioned 1*2 optical switch are connected, allowing the common optical carrier to be transmitted to the configuration module 214. After the common optical carrier passes through the optical switch, the input port and the second port of the optical switch are connected, allowing the second optical carrier to be transmitted to the first wavelength selection control module 202.

[0190] As can be seen, the solution in this application achieves the deployment of an all-optical base station by using optical devices and a network deployment architecture; the use of RSOA technology enables the uplink and downlink of the base station to use the same optical carrier, that is, the same optical carrier is used as the mixing signal for microwave signals in the optical domain, thus achieving frequency synchronization and avoiding the electrical noise and interference caused by using electrical mixers, which require costly correction schemes; the use of RSOA and wavelength selection control devices achieves the non-discriminatory deployment of remote RRHs, solving some limitations of traditional electrical devices. For example, the larger the bandwidth and the higher the specifications of traditional base stations using electrical devices, the higher the cost and the more complex the structure of the base station. The solution provided in this application has more advantages.

[0191] For example, when an optical fiber in a ring network fails, the RRH design can automatically switch over, interrupting signal transmission in the ring network and switching it to tree-like transmission to achieve bidirectional data transmission. Figure 4 As shown, when RRH k-1 and RRH k After the fiber optic cable fault, i.e., RRH k-1 and RRH k The intermediate fiber optic link was interrupted, from RRH1 to RRH k-1 Uplink and downlink communication links will not be affected, RRH1 to RRH k-1 It will be transmitted in the original manner, RRH k To RRH N Due to fiber optic cable interruption, no downlink signal can be received. RRH k To RRH N After the second monitoring module 213 detects an abnormal optical receiving power (i.e., no optical signal is detected), it activates the second optical switch 204 to switch. The working principle of the second monitoring module 213 in the RRH is the same as that of the first monitoring module in the CO device. It determines whether there is an abnormality in the optical power in the optical fiber. If an abnormality is found, it will activate the switching of the optical switch. Figure 7As shown, for RRH k The downlink signal (i.e., the second optical carrier) is input from the third port of the second optical circulator 201 and output from the fourth port; the uplink signal (i.e., the third optical carrier) is input through the second port of the second optical circulator 201 after passing through the second optical switch 204, and is output from the third port of the second optical circulator 201 to be transmitted in the optical fiber.

[0192] See Figure 9 , Figure 9 This is an interactive flowchart illustrating a communication method provided in an embodiment of this application. The method is applied to a base station, which includes a CO device, a processing module, and multiple RRHs, wherein the multiple RRHs form a ring network via optical fibers. Figure 9 As shown, the method includes:

[0193] The S901 and CO devices generate N first optical carriers and modulate the baseband signal onto the N first optical carriers to obtain N second optical carriers.

[0194] Among them, the wavelengths of the N first optical carriers are all different.

[0195] Specifically, each of the N first optical carriers contains a radio frequency signal. The baseband signal is modulated onto the N first optical carriers to obtain N second optical carriers. Specifically, the baseband signal is modulated onto the video signal of each of the N first optical carriers to obtain N second optical carriers.

[0196] The S902 and CO devices transmit N second optical carriers to the processing module.

[0197] Specifically, the CO device is connected to the processing module via a first optical fiber and a second optical fiber; the transmission of the optical carrier between the CO device and the processing module is achieved through either the first optical fiber or the second optical fiber; when the optical fiber fails, the optical carrier is transmitted between the CO device and the processing module through the other optical fiber.

[0198] S903, the processing module transmits N second optical carriers to RRH.

[0199] The processing module is coupled to a ring network consisting of multiple RRHs. Specifically, the processing module transmits N second optical carriers to the RRHs by transmitting the N second optical carriers to the ring network.

[0200] When the optical fiber between two adjacent RRHs in the ring network is working normally, the processing module controls N second optical carriers to transmit along the first direction in the ring network. When the optical fiber between any two adjacent RRHs in the ring network is malfunctioning, the processing module controls N second optical carriers to transmit along the first direction and the second direction in the ring network. The first direction can be clockwise or counterclockwise, and the second direction can be clockwise or counterclockwise. The first direction and the second direction are not the same.

[0201] S904 and RRH obtain the target optical carrier from the received second optical carrier, and obtain the first target optical carrier and the second target optical carrier based on the target optical carrier. The first target optical carrier is converted into an electrical signal for transmission, and the data in the second target optical carrier is erased to obtain the seed optical signal. The received uplink signal is modulated onto the seed optical signal to obtain the third optical carrier.

[0202] In an optional embodiment, the wavelength of the target optical carrier acquired by the RRH is the same as the wavelength of the optical carrier required by the RRH, or the RRH acquires the target optical carrier from the received second optical carrier according to wavelength selection information.

[0203] S905 and RRH transmit the third optical carrier to the processing module.

[0204] S906, the processing module transmits the third optical carrier to the CO device.

[0205] Specifically, after receiving the third optical carrier, the CO device demultiplexes the received third optical carrier.

[0206] It should be noted that the specific functions of the aforementioned CO equipment, processing module, and RRH can be found in the above description. Figures 2-8 The descriptions of CO device 100, processing module 300 and RRH 200 are not repeated here.

[0207] It should be noted that the solution of this application integrates optical technology and wireless technology. The architecture and protection scheme of this application can be used in the optical technology field, such as wavelength division multiplexing (WDM) networking architecture.

[0208] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A communication system, characterized in that, The communication system includes: a central office (CO) device and multiple remote radio heads (RRHs), wherein the multiple RRHs form a ring network through optical fibers, and the CO device is connected to the ring network through a first optical fiber and a second optical fiber. The CO device is used to modulate a baseband signal onto N first optical carriers generated by the CO device to obtain N second optical carriers, and to transmit the N second optical carriers to the ring network through the first optical fiber, so that the N second optical carriers are transmitted along a first direction on the ring network; the wavelengths of the N first optical carriers are all different, and N is an integer greater than 0; the CO device is also used to transmit the N second optical carriers to the ring network through a second optical fiber when the first optical fiber fails; Any one of the plurality of RRHs is used to obtain a target optical carrier from the received second optical carrier, transmit the optical carriers other than the target optical carrier from the received second optical carrier back to the ring network; convert the target optical carrier into an electrical signal, and transmit the electrical signal as a downlink signal; the RRH includes a configuration module, which is used to obtain a common optical carrier and parse wavelength selection information from the common optical carrier, the wavelength selection information being used to obtain the target optical carrier from the received second optical carrier; Any of the RRHs is further configured to obtain a seed optical signal based on the target optical carrier, modulate the received uplink signal onto the seed optical signal to obtain a third optical carrier, and transmit the third optical carrier to the CO device; The communication system further includes a processing module connected between the CO device and the ring network, and the processing module is connected to the CO device via the first optical fiber and the second optical fiber. The processing module is used to control the N second optical carriers to transmit along the first and second directions in the ring network when a fiber optic failure occurs between two adjacent RRHs in the ring network. The first direction and the second direction are different.

2. The communication system according to claim 1, characterized in that, Any two adjacent RRHs among the plurality of RRHs are connected by one or two optical fibers.

3. A central office CO device, characterized in that, The CO device is applied to the communication system according to claim 1 or 2, and the CO device includes: a microwave photon generation module, a modulation module, a multiplexing module, a first optical circulator, a first optical switch, a demultiplexing module, and a receiving array; The microwave photon generation module is connected to the multiplexing module through the modulation module. The multiplexing module is connected to the first port of the first optical circulator. The second port of the first optical circulator is connected to the first port of the first optical switch. The third port of the first optical circulator is connected to the receiving array through the demultiplexing module. The second or third port of the first optical switch is the input / output port of the CO device. The second port of the first optical switch is connected to one end of the first optical fiber, and the third port of the first optical switch is connected to one end of the second optical fiber. The CO device is configured to be located outside the ring network composed of multiple remote radio heads (RRHs) and is connected to the processing module through the other ends of the first and second optical fibers. The microwave photon generation module is used to generate N first optical carriers and transmit the N first optical carriers to the modulation module; the wavelengths of the N first optical carriers are all different; N is an integer greater than 0. The modulation module is used to modulate the baseband signal onto the N first optical carriers to obtain N second optical carriers, and transmit the N second optical carriers to the multiplexing module, wherein each of the N second optical carriers carries the baseband signal; The multiplexing module is used to converge the N second optical carrier signals onto a single optical path, input them to the first port of the first optical circulator, input them from the second port of the first optical circulator to the first port of the first optical switch, and then output them through the second or third port of the first optical switch. The demultiplexing module is used to demultiplex the third optical carrier and transmit the demultiplexed optical carrier to the receiving array. The third optical carrier is input through the second or third port of the first optical switch, passes through the first port of the first optical switch, is input from the second port of the first optical circulator, and is output from the third port of the first optical circulator to the demultiplexing module. The CO device also includes a first monitoring module, which is connected to the control port of the first optical switch. The first monitoring module is used to detect whether there is an optical signal between the first port and the second port of the first optical switch, or between the first port and the third port of the first optical switch; If no optical signal is detected when the first port and the second port of the first optical switch are connected and the first port and the third port of the first optical switch are disconnected, then the first port and the second port of the first optical switch are disconnected and the first port and the third port of the first optical switch are connected, so that the N second optical carriers are output through the third port of the first optical switch. If no optical signal is detected when the first port and the third port of the first optical switch are connected and the first port and the second port of the first optical switch are disconnected, then the first port and the second port of the first optical switch are connected and the first port and the third port of the first optical switch are disconnected, so that the N second optical carriers are output through the second port of the first optical switch.

4. The CO device according to claim 3, characterized in that, The multiplexing module is an arrayed waveguide grating (AWG).

5. The CO device according to claim 3 or 4, characterized in that, The modulation module includes N modulators. The i-th modulator among the N modulators is used to modulate the baseband signal onto the i-th first optical carrier among the N first optical carriers to obtain the i-th second optical carrier among the N second optical carriers. Where i = 1, 2, 3, ..., N.

6. A wireless remote radio frequency head (RRH), characterized in that, The RRH is applied to the communication system as described in any one of claims 1-2, and the RRH includes: a wavelength selection circuit, a signal processing circuit, and a transmitting and receiving circuit. Wherein, the first port and the second port of the wavelength selection circuit are respectively the first port and the second port of the RRH, the third port and the fourth port of the wavelength selection circuit are respectively connected to the first port and the second port of the signal processing circuit, and the third port of the signal processing circuit is connected to the input and output ports of the transmitting and receiving circuit. The wavelength selection circuit is used to obtain the target optical carrier from the second optical carrier received from port 1, and output the optical carriers other than the target optical carrier from the received second optical carrier from port 2. Port 1 is the first port or the second port of the wavelength selection circuit, and port 2 is the first port or the second port of the wavelength selection circuit. Port 1 and port 2 are not the same. The signal processing circuit is used to split the optical carrier input from the first port of the signal processing circuit into a first target optical carrier and a second target optical carrier; convert the first target optical carrier into an electrical signal and transmit it to the transmitting and receiving circuit; erase the baseband signal in the second target optical carrier to obtain a seed optical signal; modulate the uplink signal received by the transmitting and receiving circuit onto the seed optical signal to obtain a third optical carrier; and output the third optical carrier to the wavelength selection circuit through the second port of the signal processing circuit. The transmitting and receiving circuit is used to transmit the electrical signal obtained by the signal processing circuit and to receive the uplink signal. The wavelength selection circuit is used to output the received third optical carrier through port 1; The wavelength selection circuit includes a second optical circulator, a first wavelength selection control module, a second wavelength selection control module, and a second optical switch. Wherein, the first port and the third port of the second optical circulator are respectively the first port and the second port of the wavelength selection circuit, the second port and the fourth port of the second optical circulator are respectively connected to the first port and the second port of the second optical switch through the first wavelength selection control module and the second wavelength selection control module, and the third port and the fourth port of the second optical switch are respectively the third port and the fourth port of the wavelength selection circuit. When the second optical carrier is input from the first port of the second optical circulator and output to the first wavelength selection control module through the second port of the second optical circulator, The first wavelength selection control module is used to obtain the target optical carrier from the received second optical carrier, output the target optical carrier to the first port of the second optical switch, and then output it from the third port of the second optical switch; and output the optical carriers other than the target optical carrier from the received second optical carrier to the second port of the second optical circulator, and then output them from the third port of the second optical circulator. The second optical circulator is used to output the third optical carrier, which is input from the fourth port and the second port of the second optical switch and input to the fourth port of the second optical circulator via the second wavelength selection control module, from the first port of the second optical circulator. When the second optical carrier is input from the third port of the second optical circulator and output to the second wavelength selection control module through the fourth port of the second optical circulator, The second wavelength selection control module is used to obtain the target optical carrier from the received second optical carrier, output the target optical carrier to the second port of the second optical switch, and then output it from the third port of the second optical switch; and output the optical carriers other than the target optical carrier from the received second optical carrier to the fourth port of the second optical circulator, and output them from the first port of the second optical circulator. The second optical circulator is used to output the third optical carrier, which is input from the fourth port and the first port of the second optical switch and input to the second port of the second optical circulator via the first wavelength selection control module, from the third port of the second optical circulator. The wavelength selection circuit further includes: a configuration module, wherein a first port of the configuration module is connected to a second port of the second optical circulator, and the second port of the configuration module is connected to the first wavelength selection control module and the second wavelength selection control module; The configuration module is used to obtain a common optical carrier from the optical carrier output from the second port of the second optical circulator, and to parse wavelength selection information from the common optical carrier; and to transmit the wavelength selection information to the first wavelength selection control module and the second wavelength selection control module, so that the first wavelength selection control module or the second wavelength selection control module obtains the target optical carrier from the received second optical carrier according to the wavelength selection information.

7. The RRH according to claim 6, characterized in that, The wavelength selection circuit further includes a second monitoring module, which is connected to the control terminal of the second optical switch. The second monitoring module is used to detect whether there is an optical signal passing through the second optical switch, and to control the connection and disconnection between the ports of the second optical switch according to the detection result; If no optical signal is detected when the first port and the third port of the second optical switch are connected and the second port and the fourth port are connected, the first port and the fourth port of the second optical switch are connected and the second port and the third port are connected. If no optical signal is detected when the first port and the fourth port of the second optical switch are connected and the second port and the third port are connected, the control switches to connect the first port and the third port and the second port and the fourth port.

8. The RRH according to claim 6 or 7, characterized in that, The signal processing circuit includes: a power divider module, a reflective semiconductor optical amplifier RSOA, a low-noise amplifier LNA, a photodiode PD, and an optical isolator. The input port of the power divider module and the inverting terminal of the optical isolator are respectively the first and second ports of the signal processing circuit. The first output port of the power divider module is connected to the first port of the RSOA, the second output port of the power divider module is connected to the first port of the PD, the second port of the RSOA is connected to the first port of the LNA, and the third port of the RSOA is connected to the non-inverting terminal of the optical isolator. The second port of the LNA and the second port of the PD constitute the third port of the signal processing circuit. The power splitter module is used to split the target optical carrier input from its input port into a first target optical carrier and a second target optical carrier, and output the first target optical carrier and the second target optical carrier to the RSOA and the PD respectively through the first output port and the second output port; The PD is used to convert the second target optical carrier into an electrical signal and output it from the second port of the PD; The RSOA is used to erase the baseband signal carried in the first target optical carrier to obtain a seed optical signal; and to modulate the uplink signal input from the second port of the RSOA onto the seed optical signal to obtain a third optical carrier, which is then output through the optical isolator. The uplink signal is transmitted from the second port of the LNA through its first port to the second port of the RSOA.

9. A communication method, characterized in that, Applied to the communication system as described in any one of claims 1-2, the communication system comprising a plurality of RRHs, the plurality of RRHs being connected by a ring network of optical fibers, comprising: The baseband signal is modulated onto N generated first optical carriers to obtain N second optical carriers, wherein the wavelengths of the N first optical carriers are all different, and N is an integer greater than 0; the N second optical carriers are transmitted in the ring network along a first direction; Obtain the target optical carrier from the second optical carrier received by any of the plurality of RRHs, convert the target optical carrier into an electrical signal, and transmit the electrical signal as a downlink signal; The method further includes: The seed light signal is obtained based on the target optical carrier; The received uplink signal is modulated onto the seed optical signal to obtain the third optical carrier; The communication system further includes a CO device, which is connected to the ring network via a first optical fiber and a second optical fiber. The method includes: When a fault is detected in the first optical fiber, the optical carrier is transmitted between the CO device and the ring network via the second optical fiber.

10. The method according to claim 9, characterized in that, The method further includes: When a fiber optic cable between two adjacent RRHs in the ring network fails, the N second optical carriers are controlled to transmit along the first and second directions in the ring network. The first direction and the second direction are different.

11. A communication method, characterized in that, The method is applied to the CO device as described in any one of claims 3-5, wherein the CO device is connected to the ring network via a first optical fiber and a second optical fiber, and multiple RRHs form the ring network via optical fibers, including: The baseband signal is modulated onto N generated first optical carriers to obtain N second optical carriers, wherein the wavelengths of the N first optical carriers are all different, and N is an integer greater than 0; The N second optical carriers are multiplexed onto a single optical path and output through the first optical fiber; When a fault is detected in the first optical fiber, the system switches to the second optical fiber for optical carrier transmission.

12. The method according to claim 11, characterized in that, The method further includes: A third optical carrier is obtained through the first optical fiber, and the third optical carrier carries an uplink signal; The third optical carrier is demultiplexed.

13. A communication method, characterized in that, The method is applied to the wireless remote radio head (RRH) as described in any one of claims 6-8, and the method includes: Obtain the target optical carrier from the received second optical carrier. A first target optical carrier and a second target optical carrier are obtained based on the target optical carrier; both the first target optical carrier and the second target optical carrier carry baseband signals; The first target optical carrier is converted into an electrical signal, and the electrical signal is transmitted as a downlink signal; The baseband signal in the second target optical carrier is erased to obtain a seed optical signal; and the received uplink signal is modulated onto the seed optical signal to obtain a third optical carrier. The step of obtaining the target optical carrier from the received second optical carrier includes: The target optical carrier is obtained from the received second optical carrier based on the wavelength selection information.

Images