Dual-frequency digital optical fiber repeater capable of simultaneously transmitting digital and analog signals

Abstract

The utility model provides a dual-frequency digital optical fiber repeater capable of simultaneously transmitting digital and analog signals, which comprises a near-end machine and a plurality of far-end machines, wherein the input end of the near-end machine is provided with a first radio frequency bidirectional port and a second radio frequency bidirectional port, and the output end of the near-end machine is provided with four optical fiber bidirectional interfaces; one input end of the far-end machine is provided with an optical fiber bidirectional interface corresponding to the near-end machine, and the far-end machine and the near-end machine are connected; and the other input end of the far-end machine is connected with one input end of the other far-end machine. The system has the advantages that after the near-end machine is connected with the far-end machine through the output bidirectional port of the far-end machine, the far-end machine is connected with the other far-end machine, and the like, so that a network topology structure is formed, the layout scene can be expanded, optical fiber and leaky coaxial cable resources along a railway can be fully utilized, dual-band signals including 450MHz analog signals and 400MHz digital signals can be transmitted at the same time, and the system can be widely applied to the field of railway communication. The layout cost is reduced, and economic benefits are achieved.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic repeater communication, and in particular to a dual-frequency digital fiber optic repeater that simultaneously transmits 450 MHz analog train control signals and 400 MHz digital intercom signals for railways. Background Technology

[0002] Fiber optic repeaters are radio transmitters that enhance signals during wireless communication transmission. They are widely used to eliminate localized signal shadows or weak signal areas caused by tall buildings, mountainous terrain, and other obstacles. Installing fiber optic repeaters not only improves coverage but also significantly reduces the cost of investing in base stations.

[0003] A fiber optic repeater is a device that uses software-defined radio technology to extend radio frequency coverage. It consists of a near-end unit and at least one far-end unit. The near-end unit digitizes the signal from the system's wireless interface and converts it into a CPRI standard interface, which is then transmitted to the far-end unit via optical fiber. The far-end unit receives the data through the CPRI standard interface and, after digital-to-analog conversion, regenerates and amplifies the radio frequency signal to achieve extended coverage of the base station signal.

[0004] In my country's train wireless dispatching communication system, particularly on branch lines and mountainous railways, 450MHz analog intercom technology is still used. This is my country's first-generation dedicated mobile communication system, primarily used on conventional railways for communication between station staff, assistant staff, and train drivers. The 450MHz analog train dispatching system is severely outdated, with most systems having been in service for over 10 years, and needs to be upgraded to a 400MHz digital train wireless communication system. To ensure the stable operation of the train dispatching system, both 450MHz analog and 400MHz digital systems will coexist for a period of time.

[0005] Meanwhile, due to the poor signal of the public railway network in mountainous areas, and the inability of 450MHz analog train dispatching to be used for maintenance and repair work such as engineering, power supply, and power supply along the railway line, there is an urgent need to build a digital intercom system based on 400MHz.

[0006] Signal coverage along mountain railway lines mainly includes two parts: stations and surrounding areas, and tunnels and cuttings along the route. The former is covered by station tower antennas, while the latter is covered by fiber optic repeaters and leaky cable. Currently, the fiber optic repeaters in use only support the transmission of one analog signal or one digital signal. If it is necessary to transmit analog and digital signals of different frequency bands simultaneously, two sets of fiber optic repeaters and twice the amount of fiber optic resources are required.

[0007] Therefore, how to provide a digital fiber optic repeater that can transmit signals in two frequency bands simultaneously has become an urgent problem to be solved. Utility Model Content

[0008] This invention provides a dual-frequency digital fiber optic repeater for simultaneous transmission of digital and analog signals, in order to solve the problems in the prior art.

[0009] To achieve the above objectives, this utility model provides a dual-frequency digital fiber optic repeater for simultaneous transmission of digital and analog signals, comprising a near-end unit and a far-end unit: the near-end unit has a first RF bidirectional port and a second RF bidirectional port at its input end, and four fiber optic bidirectional interfaces at its output end; one input end of the far-end unit has a fiber optic bidirectional interface corresponding to that of the near-end unit, and the two are connected; the other input end of the far-end unit is connected to an input end of another far-end unit.

[0010] As a preferred embodiment of the above technical solution, preferably, the remaining output fiber optic bidirectional interfaces of the near-end unit are connected to the input ends of different far-end units via fiber optic cables.

[0011] As a preferred embodiment of the above technical solution, preferably, another input terminal of the other remote unit is connected to other remote units via an optical fiber cable.

[0012] As a preferred option of the above technical solution, the remote unit is preferably located in a signal blind spot.

[0013] As a preferred embodiment of the above technical solution, the remote unit is preferably located in a signal-blocking area.

[0014] As a preferred embodiment of the above technical solution, the other remote units are preferably located in signal blind spots or signal blocking areas.

[0015] As a preferred embodiment of the above technical solution, preferably, each of the near-end units and each of the far-end units has an integrated power amplifier and a duplexer.

[0016] This utility model provides a dual-frequency digital fiber optic repeater for simultaneous transmission of digital and analog signals, including a near-end unit and a far-end unit: the near-end unit has a BS1 RF bidirectional port and a BS2 RF bidirectional port at its input end, and four fiber optic bidirectional interfaces at its output end; one of the input ends of the far-end unit has a fiber optic bidirectional interface corresponding to the near-end unit, and the two output bidirectional ports of the far-end unit are equipped with corresponding integrated power amplifier devices; each of the integrated power amplifier devices is equipped with a duplexer.

[0017] The advantage of this invention is that by using the bidirectional output port of the remote unit to connect the near-end unit to the remote unit, and then connecting the remote unit to another remote unit, and so on, a network topology can be formed. This can expand the deployment scenarios, make full use of the optical fiber and leaky cable resources along the railway line, and transmit dual-band signals including 450MHz analog signals and 400MHz digital signals at the same time, thereby reducing deployment costs and having great economic benefits. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the internal structure of the near-end unit in a dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission provided by this utility model.

[0020] Figure 2 This is a schematic diagram of the internal structure of the remote unit in a dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission provided by this utility model.

[0021] Figure 3 This is a schematic diagram of the network structure of a dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission based on the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] The structure provided by this utility model will now be described, such as... Figure 1 and Figure 2 As shown.

[0024] Figure 1 The input end of the near-end unit 1 shown has a first radio frequency bidirectional port BS1 and a second radio frequency bidirectional port BS2, which are used to transmit and receive 450MHz analog base station and 400MHz digital base station signals, respectively; the output end has four fiber optic bidirectional interfaces OP1, OP2, OP3 and OP4, which can be connected to different remote units 2 in different areas through fiber optic cables.

[0025] Figure 2 The remote unit 2 shown has a first bidirectional input port OP-1 and a second bidirectional input port OP-2. The first bidirectional input port OP-1 is connected to one of the fiber optic bidirectional interfaces OP1, OP2, OP3 and OP4 of the near-end unit 1. The second bidirectional input port OP-2 is used to cascade the fiber optic bidirectional interfaces of other remote units 2 inputs to form a network structure.

[0026] The remote unit 2 has two bidirectional output ports and an integrated power amplifier 22 that is matched with the AD / DA 21. Each integrated power amplifier is equipped with a duplexer 23.

[0027] Remote units are installed in signal blind spots or signal-blocked areas such as mountainous areas, tunnels, and road cuts, so that the network structure can enhance and cover signals in these areas with weak signals.

[0028] The following is a description of the near-end unit 1 and the far-end unit 2 used to implement the technical solution of this utility model. This description is based on the near-end unit with model number VIG-R0400-MU and the far-end unit with model number VIG-R0400-RU:

[0029] The first RF bidirectional port BS1 of near-end unit 1 receives the downlink signal from 450MHz analog base station A, and the second RF bidirectional port BS2 receives the downlink signal from 400MHz digital base station B. Inside near-end unit 1, frequency shifting, A / D conversion, digitization, and conversion to CPRI standard interface signal are performed sequentially. The signal is then converted into an optical signal and sent to far-end unit 2. Far-end unit 2 performs digital signal conversion, D / A conversion, signal amplification, and sends the received optical signal to the bidirectional interface antennas MS1 and MS2 of far-end unit 2 via a duplexer for transmission.

[0030] The bidirectional interface MS1 of remote unit 2 receives the uplink signal from mobile station C at 450MHz, and the bidirectional interface MS2 receives the uplink signal from mobile station D at 400MHz. Inside remote unit 2, these signals are input via duplexer 24 and sequentially amplified, converted to an A / D converter, digitized, and converted to a CPRI standard interface signal before being transmitted to near unit 1 via the fiber optic OP-1 interface. Near unit 1 receives the optical signal from remote unit 2 and sequentially performs digital signal processing, D / A conversion, and frequency shift amplification. The 450MHz signal is transmitted via the antenna of the first RF bidirectional port BS1, and the 400MHz signal is transmitted via the antenna of the second RF bidirectional port BS2. Both bidirectional interfaces MS1 and MS2 of remote unit 2 have both transmission and reception capabilities.

[0031] Further integration Figure 1 and Figure 2 The structure shown illustrates the technical solution of this utility model: This utility model provides a dual-frequency digital fiber optic repeater for simultaneous transmission of digital and analog signals, consisting of a near-end unit and one or more far-end units, capable of simultaneously transmitting downlink signals from a base station and uplink signals from a mobile station in two different frequency bands.

[0032] For ease of description, in this embodiment, dual frequency refers to the 450MHz band and the 400MHz band respectively. In actual application, it can be changed according to the frequency used. For specific modification methods and frequency bands, please refer to the instruction manual of the actual device.

[0033] like Figure 1 As shown, the near-end unit 1 has two bidirectional radio frequency ports, namely BS1 and BS2, which serve as input terminals. The first bidirectional radio frequency port BS1 is connected to the radio frequency signal of the 450MHz band analog base station A, and the second bidirectional radio frequency port BS2 is connected to the radio frequency signal of the 400MHz band digital base station B.

[0034] The near-end unit 1 is model VIG-R0400-MU, in which the FPGA digital processing unit (chip) 24 is model XC7A35T, the AD / DA (unit) 21 is model ECR8668, the optical transmission unit 25 is model H6GBT2R3-L2DT, the TRX1 module 26 is model PALNA468 / 458, and the TRX2 module 27 is model PALNA414 / 404.

[0035] Remote unit 2 is model VIG-R0400-RU, whose FPGA digital processing unit (chip) 24 is model XC7A35T, AD / DA (unit) 21 is model ECR8668, and optical transmission unit is model H6GBT2R3-L2DT. The base station downlink signal flows from near-end unit 1 to remote unit 2, and the mobile station uplink signal flows from remote unit 2 to near-end unit 1.

[0036] Specifically:

[0037] For the downlink signal of the base station, the radio frequency signal from the first radio frequency bidirectional port BS1 is processed by the frequency shifting of the TRX1 module 26 and then sent to the AD / DA unit 21 for conversion, which converts the analog radio frequency signal into a digital signal; similarly, the radio frequency signal from the second radio frequency bidirectional port BS2 is processed by the frequency shifting of the TRX2 module 27 and then sent to the AD / DA unit 21 for conversion, which converts the analog radio frequency signal into a digital signal; the two digital signals are then digitized by the FPGA digital processing unit (chip) 21 and converted into CPRI standard interface signals, which are then converted into optical signals by the optical transmission unit 25 and transmitted to the digital fiber optic remote unit 2; the output end of the near-end unit 1 has a total of 4 fiber optic bidirectional interfaces OP-1, OP-2, OP-3 and OP-4, which can transmit to the digital fiber optic remote unit 2 in 4 directions at the same time.

[0038] When the optical transmission unit 25 of the near-end unit 1 receives the CPRI standard interface signal from the far-end unit from the optical fiber bidirectional interface, the FPGA digital processing unit (chip) 21 (model XC7A35T) inside it converts it into digital signals of different frequency bands and sends them to the corresponding D / A 21 (model ECR8668) for conversion. The D / A 21 converts the digital signals into analog signals. The 450MHz band signal is frequency-shifted and amplified by the TRX1 module 26 and sent to the first RF bidirectional port BS1 interface antenna for transmission. The 400MHz band signal is frequency-shifted and amplified by the TRX2 module 27 and sent to the second RF bidirectional port BS2 interface antenna for transmission.

[0039] like Figure 2 As shown, the remote unit 2 has two bidirectional RF output ports: bidirectional interface MS1 and bidirectional interface MS2. The bidirectional interface MS1 is connected to the RF signal of the 450MHz band mobile station, and the bidirectional interface MS2 is connected to the RF signal of the 400MHz band mobile station.

[0040] For the base station downlink signal, the optical transmission unit 25 receives the CPRI standard interface signal from the remote unit 2 via the fiber optic bidirectional interface OP-1. On one hand, it can forward the signal from the fiber optic bidirectional interface OP-2 to the next remote unit 2 connected via fiber optic cable. On the other hand, it sends the CPRI standard interface signal to the FPGA digital processing unit (chip) 24 (model XC7A35T) to convert it into digital signals of different frequency bands, and then sends it to the corresponding AD / DA 21 (model ECR8668) for conversion. This converts the digital signal into an analog signal, and the 450MHz band signal is then processed by the integrated power amplifier 22 (…). Figure 2 The upper and middle parts of the signal are processed and amplified before being passed through a duplexer 23. Figure 2 The upper-middle section is transmitted via the MS1 interface antenna, and the 400MHz band is transmitted through the integrated power amplifier 22 ( Figure 2 The lower half of the signal is processed and amplified before being passed through a duplexer 23. Figure 2 The lower half of the signal is transmitted via the MS2 interface antenna.

[0041] For the mobile station uplink signal, duplexer 23 ( Figure 2 The upper-middle section receives RF signals from the MS1 bidirectional port and transmits them via the integrated power amplifier 22. Figure 2 The upper half of the signal is processed and amplified before being sent to a DA / AD converter (model ECR8668) to convert the analog radio frequency signal into a digital signal; similarly, the duplexer 23 ( Figure 2 The lower half of the receiver receives RF signals from the MS2 bidirectional port and transmits them via the integrated power amplifier 22. Figure 2The lower half of the signal is processed and amplified before being sent to the AD / DA21 converter, which converts the analog radio frequency signal into a digital signal. The two digital signals are then digitized by the FPGA digital processing unit 24 and converted into CPRI standard interface signals. The optical transmission unit 25 converts them into optical signals and transmits them to the near-end unit 1 through the op-1 interface.

[0042] The technical solution of this utility model will be illustrated in detail below with specific embodiments. A railway has a 450 MHz analog train dispatching system and a 400 MHz digital intercom system. The station has a 450 MHz analog base station and a 400 MHz digital base station. Since the base station can only cover the area around the station, dual-frequency digital fiber optic repeaters are needed to extend the coverage of the base station signals in the mountainous areas E and F along the route between the stations, so as to ensure that there are no communication coverage blind spots along the railway and realize the smooth operation of the two communication systems along the entire line.

[0043] Fiber optic repeater near-end unit 1 is deployed at the station, and fiber optic repeater far-end units 2 are deployed in mountainous areas E and F respectively. Figure 3 As shown.

[0044] The RF signal of the 450 MHz analog base station A placed in the station is connected to the first RF bidirectional port BS1 of the near-end unit via coupler a. The RF signal of the 400 MHz digital base station B placed in the station is connected to the second RF bidirectional port BS2 of the same near-end unit via coupler b. The near-end unit is connected to the optical port OP-1 of the remote unit in mountainous area E through port OP1. The remote unit in mountainous area E is connected to the optical port OP-1 of the remote unit in mountainous area F through port OP2.

[0045] The downlink signals from the 450 MHz analog base station A and the 400 MHz digital base station B are sequentially processed by frequency shifting, A / D conversion, digitization, and conversion into CPRI standard interface signals within the near-end unit 1. These signals are then converted into optical signals and transmitted to the remote units 2 in mountainous areas E and F, respectively. The remote units 2 sequentially convert the received optical signals into digital signals, perform D / A conversion, amplify the signals, and transmit them via a duplexer to the MS1 and MS2 interface antennas. In this way, the 450 MHz mobile station receives the downlink signal from the station's 450 MHz analog base station, and the 400 MHz mobile station receives the downlink signal from the station's 400 MHz digital base station B.

[0046] Remote unit 2 in mountainous areas E and F receives the 450 MHz mobile station uplink signal via its MS1 port and the 400 MHz mobile station uplink signal via its MS2 port. Internally, the remote units sequentially amplify the signal, perform A / D conversion, digitize the signal, and convert it to a CPRI standard interface signal. Remote unit E transmits the signal to the near-end unit via the fiber optic OP-1 interface, while remote unit 2 in mountainous area F transmits the signal to remote unit E's OP-2 interface via the fiber optic OP-1 interface, and then transmits it to the near-end unit via its own OP-1 interface. The near-end unit receives the optical signal from the remote units and sequentially performs digital signal processing, D / A conversion, and frequency shift amplification. The 450 MHz signal is transmitted via the first RF bidirectional port BS1 interface antenna, and the 400 MHz signal is transmitted via the second RF bidirectional port BS2 interface antenna. Thus, the 450 MHz analog base station receives the 450 MHz mobile station uplink signal, and the 400 MHz digital base station receives the 400 MHz mobile station uplink signal.

[0047] With the dual-frequency digital fiber optic repeater provided by this utility model, the signals of the 450 MHz analog train dispatching system and the 400 MHz digital intercom system can be extended from the station coverage to the mountainous area, and can be transmitted simultaneously without affecting each other.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission, characterized in that, Includes near-end units and several remote units: The near-end unit has a first radio frequency bidirectional port and a second radio frequency bidirectional port at its input end, and four optical fiber bidirectional interfaces at its output end. One of the input terminals of the remote unit has a corresponding bidirectional fiber optic interface that connects the two to the near unit. The other input terminal of the remote unit is connected to an input terminal of another remote unit.

2. The dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission according to claim 1, characterized in that, The remaining output fiber optic bidirectional interfaces of the near-end unit are connected to the input terminals of different far-end units via fiber optic cables.

3. The dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission according to claim 1, characterized in that, The other input terminal of the other remote unit is connected to other remote units via fiber optic cable.

4. The dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission according to claim 1, characterized in that, The remote unit is located in a signal blind spot.

5. The dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission according to claim 1, characterized in that, The remote unit is located in a signal-blocking area.

6. The dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission according to claim 4 or 5, characterized in that, The other input terminal of the other remote unit is connected to other remote units via fiber optic cable, and the other remote units are located in signal dead zones or signal blocking areas.

7. The dual-frequency digital fiber optic repeater for simultaneous digital and analog signal transmission according to claim 1, characterized in that, Each of the near-end units and each of the far-end units contains an integrated power amplifier and a duplexer.

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