CN104967484B - Rail transit wireless MIMO communication transmission system with signals bidirectionally fed into leaky cables - Google Patents

Abstract

The invention relates to a rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables, comprising a first remote radio frequency unit, a second remote radio frequency unit, a first multi-port combiner, and a second multi-port combiner , radio frequency electro-optical converter, optical fiber, radio frequency photoelectric converter, delay compensation module, third multi-port combiner, fourth multi-port combiner, single bidirectional leaky cable, at least one first redundant backup remote radio frequency unit, at least one second redundant backup remote radio frequency unit. The system is applied to rail transit communication to realize multi-stream signal transmission, which can reduce the number of leaky cable laying by half, and has efficient MIMO performance, which greatly reduces engineering costs and simplifies construction and maintenance. It meets the needs of uplink and downlink communication, is suitable for frequency division duplex and time division duplex communication, can be used for MIMO signal coverage of rail transit communication systems, and supports multi-frequency redundant networking.

Description

Rail transit wireless MIMO communication transmission system with signals bidirectionally fed into leaky cables

technical field

The invention relates to a rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables, and belongs to the technical field of communication and electronics.

Background technique

The urban rail transit system is an important means to solve the pressure of urban transportation at present, and it is laid on a large scale in densely populated cities. The wireless communication transmission methods used in rail transit communication systems mainly include free antennas and leaky cables. Leaky cables are widely used because of their good uniform radiation characteristics, which greatly improve the safety and reliability of wireless communication. As the evolution direction of the next-generation rail transit communication system, MIMO technology will bring higher reliability, stability, throughput and the possibility of carrying multiple services to the system.

The main scenarios of rail transit communication are linear coverage scenarios such as tunnels, and satisfy the uplink and downlink communication of time division duplex or frequency division duplex. The rail transit communication network mostly adopts multi-frequency redundant networking. When the coverage of the current communication system fails, the servo system working in another frequency band can still guarantee communication. This dual-network coverage method improves the reliability of the vehicle-ground communication system. reliability. Considering the safety and reliability of rail transit communication, the deployment of MIMO communication transmission system will bring greater challenges.

At present, in the leaky cable MIMO communication transmission system used in rail transit, multiple signals are respectively fed into multiple leaky cables. The base station side converts the frequency of each signal after the baseband digital signal processing and then feeds it to the respective single leaky cable through the feeder. The antenna array is composed of multiple leaky cables in the tunnel, and realizes MIMO system communication with the vehicle antenna array. However, the laying of multiple leaky cables will inevitably bring a lot of cost investment, and the corresponding difficulty of construction and deployment will also be greatly increased.

Contents of the invention

In order to solve the high cost and construction expenses caused by the laying of multiple leaky cables in the existing rail transit MIMO communication transmission system, and realize the situation of multi-frequency redundant networking and duplex communication, the purpose of the present invention is to provide a two-way signal feed-in Rail transit wireless MIMO communication transmission system with leaky cables. The system reduces the traditional leaky cable MIMO signal transmission from two leaky cables to a single one, or reduces the number of multiple leaky cables (even numbers greater than two) by half, and has efficient MIMO performance. It meets the needs of uplink and downlink communication, is suitable for frequency division duplex and time division duplex communication, can be used for MIMO signal coverage of rail transit communication systems, and supports multi-frequency redundant networking.

To achieve the above object, the present invention adopts the following technical solutions:

A rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables, including a first remote radio frequency unit, a second remote radio frequency unit, a first multi-port combiner, a second multi-port combiner, radio-frequency electro-optic Converter, optical fiber, radio-frequency optical-to-electrical converter, delay compensation module, third multi-port combiner, fourth multi-port combiner, single bidirectional leaky cable, at least one first redundant backup remote radio unit, at least A second redundant backup remote radio frequency unit; the left end of the single bidirectional leakage cable is connected to the output of the first multi-port combiner, and the right end is connected to the output of the second multi-port combiner; the first remote radio frequency _One of the two-way signals with a unit output frequency of f1 is connected to the delay compensation module and the input of the first multi-port combiner in turn, and the other signal is connected to the input of the third multi-port combiner; one or more of the One of the two-way signals output by the first redundant backup remote radio frequency unit is sequentially connected to the delay compensation module and the input of the first multi-port combiner, and the other is connected to the input of the third multi-port combiner; the third The output of the multiport combiner is connected to the radio frequency electro-optical converter, the optical fiber, the radio frequency photoelectric converter, and the second multiport combiner in turn to form a lower closed loop; the output frequency of the _second remote radio frequency unit is a dual One of the signals is sequentially connected to the delay compensation module and the input of the second multi-port combiner, and the other signal is connected to the input of the fourth multi-port combiner; one or more of the second redundant backup remote radio frequency One of the two-way signals output by the unit is sequentially connected to the delay compensation module and the input of the second multi-port combiner, and the other is connected to the input of the fourth multi-port combiner; the output of the fourth multi-port combiner is in turn Connect the radio frequency electro-optic converter, the optical fiber, the radio frequency photoelectric converter, and the first multi-port combiner to form an upper closed loop.

The function of the radio frequency electro-optic converter, the optical fiber, and the radio frequency photoelectric converter is to reduce the loss and transmission time delay of long-distance signal transmission, and the function of the radio frequency electro-optic converter is to convert the electrical signal of radio frequency into an optical signal, so that the optical fiber can carry out For transmission, the function of the radio-frequency photoelectric converter is to convert optical signals into radio-frequency electrical signals. The function of the delay compensation module is to reduce the transmission delay and ensure the orthogonality of the MIMO signals bidirectionally fed by the leaky cable. The value of the time delay compensation in the time delay compensation module is determined by the fixed time delay generated by the radio frequency electro-optic converter, the optical fiber and the radio frequency photoelectric converter.

Further, the system also includes a plurality of single bidirectional leaky cables, a first multi-channel remote radio frequency unit, and a second multi-channel remote radio frequency unit; the first multi-channel remote radio frequency unit and the second multi-channel remote radio The radio frequency unit includes multiple radio frequency output ports, and the signals output by the multi-channel radio frequency output ports are multi-channel data signals that satisfy the orthogonality between signals, or have multiple data signals that can be separated by the receiver; multiple upper closed loops The loop and the lower closed loop are connected to a first multi-channel remote radio unit and a second multi-channel remote radio unit, and a sufficient distance is set between the single bidirectional leakage cables on each loop to keep different single bidirectional cables. Uncorrelation between leaky cable radiated signals.

Further, the system also includes one or more first multi-path redundant backup remote radio frequency units, and a second multi-path redundant backup remote radio frequency unit; the one or more first multi-path redundant backup remote radio units One of the multi-channel signals output by the radio frequency unit is sequentially connected to the delay compensation module and the input of the first multi-port combiner, and the other signal is connected to the third multi-port combiner; the one or more second multiple redundant One of the multiple signals output by the redundant backup remote radio frequency unit is sequentially connected to the delay compensation module and the input of the second multi-port combiner, and the other signal is connected to the fourth multi-port combiner.

The first redundant backup remote radio frequency unit provides a redundant backup function that is identical to the output data signal of the first remote radio frequency unit and has a frequency difference; the second redundant backup remote radio frequency unit provides the same The output data signal of the second remote radio frequency unit is exactly the same, and the redundant backup function of the frequency difference.

Compared with the prior art, the present invention has the following prominent substantive features and remarkable advantages:

The invention is a rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables. It is applied to rail transit communications to realize multi-channel signal transmission, has efficient MIMO performance, can reduce the number of leaky cables laid by half, and greatly reduces engineering costs. , Simplify construction and maintenance. It meets the needs of uplink and downlink communication, is suitable for frequency division duplex and time division duplex communication, can be used for MIMO signal coverage of rail transit communication systems, and supports multi-frequency redundant networking.

Description of drawings

Fig. 1 is a structural diagram of a multi-frequency redundant MIMO communication transmission system in the present invention that adopts two-way signal feed into a single leaky cable.

Fig. 2 is a structural diagram of a MIMO communication transmission system in which multiple signals are bidirectionally fed into multiple leaky cables according to the present invention.

Fig. 3 is an example diagram of a dual-frequency redundant communication transmission system using MIMO signals bidirectionally fed into a single leaky cable, which is applied to rail transit wireless communication.

Fig. 4 is an example diagram of a dual-frequency redundant communication transmission system using MIMO signals bidirectionally fed into dual leaky cables applied to rail transit wireless communication.

detailed description

Embodiments of the present invention will be described more fully below with reference to the accompanying drawings. The rail transit multi-frequency redundant MIMO communication transmission system described in this embodiment uses at least two remote radio frequency units for multi-channel redundant backup data transmission, and sets sufficient guard intervals between different frequencies to ensure no inter-frequency interference. The rail transit system supports uplink and downlink duplex communication, including time division duplex and frequency division duplex. The leaky cables are leaky cables with dual ports that can bidirectionally feed MIMO signals. The single-channel, dual-channel, and multi-channel are respectively represented as single-channel, dual-channel, and multi-channel MIMO signal data, wherein the multi-channel MIMO signal data is even-numbered MIMO signal data greater than two-channel. The adopted MIMO transmission modes are all space division multiplexing, using different MIMO signals to transmit different data streams.

As shown in Figure 1, a multi-frequency redundant MIMO communication transmission system using two-way signal feed into a single leaky cable, including a first remote radio unit 1, a second remote radio unit 2, a first multi-port Combiner 3, second multi-port combiner 13, radio frequency electro-optic converter 4, optical fiber 5, radio frequency photoelectric converter 6, delay compensation module 7, third multi-port combiner 8, fourth multi-port combiner 9, a single bidirectional leaky cable 10, at least one first redundant backup remote radio frequency unit 11, at least one second redundant backup remote radio frequency unit 12; the left end of the single bidirectional leaky cable 10 is connected to the first multiple The output of the port combiner 3, the right end is connected to the output of the second multi-port combiner 13; the output frequency of the first remote radio frequency unit 1 is the _one -way signal S2 of the two-way signal _{of f1, and f1} is sequentially connected with time delay The input of the compensation module 7 and the first multi-port combiner 3, another signal S _{1, f1} is connected to the input of the third multi-port combiner 8; one or more of the first redundant backup remote radio frequency units 11 One of the output dual-channel signals is sequentially connected to the input of the delay compensation module 7 and the first multiport combiner 3, and the other is connected to the input of the third multiport combiner 8; the third multiport combiner 8 The output of the radio frequency electro-optic converter 4 is connected successively, the optical fiber 5, the radio frequency photoelectric converter 6, the second multi-port combiner 13, forms a closed loop; the second remote radio frequency unit 2 output frequency is a dual frequency f ₂ A signal S ₁ of the road signal, f2 is connected to the input of the delay compensation module 7 and the second multi-port combiner 13 in turn, and another signal S _{2, f2} is connected to the input of the fourth multi-port combiner 9; one or more One of the two-way signals output by the second redundant backup remote radio frequency unit 12 is sequentially connected to the delay compensation module 7 and the input of the second multi-port combiner 13, and the other is connected to the fourth multi-port combiner 9 input; the output of the fourth multiport combiner 9 is sequentially connected to the radio frequency electro-optical converter 4, the optical fiber 5, the radio frequency photoelectric converter 6, and the first multiport combiner 3 to form an upper closed loop. The one first redundant backup remote radio frequency unit 11 outputs two-way signals S _{1, f3 and} S _{2, f3} with frequency f3, and the outputs of multiple first redundant backup remote radio frequency units 11 are different from all the above frequencies other frequency signals; the one second redundant backup remote radio frequency unit 12 outputs dual-channel signals S _{1, f4 and} S _{2, f4} with frequency f4, and multiple second redundant backup remote radio frequency units 12 output Different from other frequency signals of all the above-mentioned frequencies; the number of the delay compensation module 7 is equal to the first remote radio unit 1, the second remote radio unit 2, the first redundant backup remote radio unit 11 and the second redundant The sum of the numbers of backup remote radio frequency units 12.

The first remote radio frequency unit 1 and the second remote radio frequency unit 2 respectively generate two different data signals, the signals are multi-channel data signals that satisfy the orthogonality between signals, or have multiple data signals that can be separated by the receiver Signal. The two ends of a single bidirectional leaky cable 10 are fed with data signals at frequencies f1, f2, f3, f4, etc., and the data signals at each frequency point include the first remote radio frequency unit 1 and the second remote radio frequency unit 1. Two different data signals generated by unit 2 respectively. Different signals are radiated from different slots of a single bidirectional leaky cable 10, and receive multiple signals at the receiving end to form a multi-frequency two-transmission MIMO system. Since different data information has experienced different directional leakage channels in the cable, enough channel differences are achieved to satisfy the channel space gain. The radio frequency electro-optical converter 4, the optical fiber 5, and the radio frequency photoelectric converter 6 are used to reduce the loss and transmission time delay of long-distance signal transmission, and the radio frequency electro-optic converter 4 is used to convert the electrical signal of radio frequency into an optical signal , so that the optical fiber 5 can transmit, and the function of the radio frequency photoelectric converter 6 is to convert the optical signal into a radio frequency electrical signal. The function of the delay compensation module 7 is to reduce the transmission delay and ensure the orthogonality of the MIMO signals bidirectionally fed by the leaky cable. The value of time delay compensation in the time delay compensation module 7 is determined by the fixed time delay generated by the radio frequency electro-optic converter 4 , the optical fiber 5 and the radio frequency photoelectric converter 6 . The system meets the requirements of uplink communication at the same time, and the uplink data signal received by a single bidirectional leaky cable 10 can be received by the remote radio frequency unit through the time delay compensation module 7, the radio frequency photoelectric converter 6, the optical fiber 5, and the radio frequency electro-optic converter 4 . The multi-frequency redundant MIMO communication transmission system described in Figure 1 adopts the dual-channel signal bidirectionally fed into a single leaky cable to realize the dual-transmission MIMO communication with redundant backup of dual base stations in a rail transit system with a single leaky cable.

As shown in Figure 2, a structure diagram of a MIMO communication transmission system using multi-channel signal bidirectionally fed into multiple leaky cables, including a first multi-channel remote radio frequency unit 14, a second multi-channel remote radio frequency unit 15, a first multi-channel remote radio frequency unit 15, Multiport combiner 3, second multiport combiner 13, radio frequency electro-optic converter 4, optical fiber 5, radio frequency photoelectric converter 6, delay compensation module 7, at least one single bidirectional leaky cable 10, the second bidirectional Leaky cables16. The left end of the single bidirectional leakage cable 10 is connected to the output of the first multi-port combiner 3, and the right end is connected to the output of the second multi-port combiner 13; the output frequency of the first multi-way remote radio frequency unit 14 is f ₁ multi-channel signals S _{1-1, f1} , S _{1-2, f1} , S _{1-3, f1} , S _{1-4, f1} , etc., the output frequency of the second multi-channel remote radio frequency unit 15 is f ₂ The multi-channel signals S _{2-1, f2} , S _{2-2, f2} , S _{2-3, f2} , S _{2-4, f2} etc. different from the first multi-channel remote radio frequency unit 14; One signal S _{1-1, f1} output by a multi-channel remote radio frequency unit 14 is sequentially connected to the delay compensation module 7 and the input of the first multi-port combiner 3, and the other signal S _{1-2, f1} is sequentially connected to the radio frequency electro-optic The converter 4, the optical fiber 5, the radio frequency photoelectric converter 6, and the input of the second multi-port combiner 13 form a lower closed loop; the signal S _{2-2, f2} The delay compensation module 7 and the input of the second multi-port combiner 13 are connected in turn, and the other signal S _{2-1, f2} is sequentially connected to the radio frequency electro-optic converter 4, the optical fiber 5, the radio frequency photoelectric converter 6, the first multi-port combiner The input of circuit device 3 forms an upper closed loop. The two channels S _{1-3, f1} , S _{1-4, f1} of the other signals output by the first multi-channel remote radio frequency unit 14 and the other signals output by the second multi-channel remote radio frequency unit 15 The two paths S _{2-3, f2} , S _{2-4, f2} in the above-mentioned lower closed loop and upper closed loop form the second lower closed loop and the second upper closed loop with the second bidirectional leakage cable 16 Close the loop. One or more of the second lower closed loop and the second upper closed loop are respectively connected to the multi-channel output ports of the first multi-channel remote radio frequency unit 14 and the second multi-channel remote radio frequency unit 15 .

The signals output by the multi-channel radio frequency output ports of the first multi-channel remote radio frequency unit 14 and the second multi-channel remote radio frequency unit 15 are multi-channel data signals that satisfy the orthogonality between signals, or have the ability to be separated by the receiver. The multi-channel data signal; the multi-channel MIMO signal described in this legend represents an even number of multiple signals, and the MIMO method is space division multiplexing; the single bidirectional leaky cable 10 and one or more second bidirectional leaky cables 16 maintain Sufficient spacing ensures that the single bidirectional leaky cable 10 and the second bidirectional leaky cable 16 and multiple single bidirectional leaky cables 10 have no correlation between the radiation signals, so as to achieve efficient MIMO performance; the first multi-port combiner 3 All possess three ports with the second multi-port combiner 13; Described radio frequency electro-optical converter 4, optical fiber 5, radio frequency photoelectric converter 6, the effect of time delay compensation module 7 is described in Fig. 1 and adopts two-way signal bidirectional feed The corresponding equipment in the multi-frequency redundant MIMO communication transmission system entering a single leaky cable has the same effect. The two ends of one or more single bidirectional leaky cables 10 are fed into the dual-frequency dual-channel data signals that include frequencies f1 and f2, and the two ends of the second bidirectional leaky cable 16 are fed into dual frequency signals that include frequencies f1 and f2. Frequency dual data signal. Different signals radiate at different slot points of one or more single bidirectional leaky cables 10 and the second bidirectional leaky cable 16, and are radiated by one or more single bidirectional leaky cables 10 and the second bidirectional leaky cables 16 and the multi-antenna at the receiving end The structure forms a MIMO dual-frequency redundant system; as an extension of the dual-transmission structure of a single leaky cable, the multi-transmission structure of multiple leaky cables realizes the real MIMO communication of the rail transit system.

Application examples

Figure 3 shows an example diagram of a dual-frequency redundant communication transmission system that uses MIMO signals bidirectionally fed into a single leaky cable, which is applied to rail transit wireless communication. Not limited to the above-mentioned dual-frequency redundant networking situation, the communication transmission system can be expanded to a redundant backup structure of multiple remote radio frequency units, supporting multi-frequency redundant networking; the communication transmission system has a dual-channel MIMO transmission structure , the MIMO method is space division multiplexing;

The communication transmission system includes a first remote radio unit 1, a second remote radio unit 2, a first redundant backup remote radio unit 11, a second redundant backup remote radio unit 12, a first multi-port combination 3, a second multi-port combiner 13, a radio frequency electro-optic converter 4, an optical fiber 5, a radio frequency photoelectric converter 6, a delay compensation module 7, a single bidirectional leaky cable 10, multiple baseband processing units 17, a transmission network 18. Upper layer core equipment 19. The first remote radio frequency unit 1, the first redundant backup remote radio frequency unit 11, and the baseband processing unit 17 form the first base station end of the rail transit communication system; by the second remote radio frequency unit 2, the second Two redundant backup far-end radio frequency units 12, baseband processing unit 17 have formed the second base station end of rail traffic communication system; The length of described single bidirectional leaky cable 10 and optical fiber 5 is several hundred meters to several kilometers, is laid on Between two remote radio units. The left end of the single bidirectional leakage cable 10 is connected to the output of the first multiport combiner 3, and the right end is connected to the output of the second multiport combiner 13; the output frequency of the first remote radio frequency unit ₁ is f1 One signal S2 of the _{two-way signal, f1} is connected to the input of the time delay compensation module 7 and the first multi-port combiner 3 in turn, and the other signal S1 _{, f1} is connected to the input of the third multi-port combiner 8; The first redundant backup remote radio unit 11 outputs one signal S2 of the two-way signal whose frequency is _{f3 , and f3} is sequentially connected to the delay compensation module 7 and the input of the first multi-port combiner ₃ , and the other signal S1 _{, f3} is connected to the input of the third multiport combiner 8; the output of the third multiport combiner 8 is connected to the radio frequency electro-optic converter 4, the optical fiber 5, the radio frequency photoelectric converter 6, and the second multiport combiner 13, forming a lower closed loop; the second remote radio frequency unit 2 outputs one signal S1 of the _two -way signal whose frequency is _{f2, and f2} is sequentially connected to the delay compensation module 7 and the second multi-port combiner 13 Input, another signal S _{2, f2} is connected to the input of the fourth multi-port combiner 9; the second redundant backup remote radio frequency unit 12 outputs one signal S _{1, f4} of the two-way signal whose frequency is f ₄ in turn Connect the input of the time delay compensation module 7 and the second multiport combiner 13, and another signal S _{2, f4} connects the input of the fourth multiport combiner 9; the output of the fourth multiport combiner 9 is sequentially Connect the radio frequency electro-optical converter 4, the optical fiber 5, the radio frequency photoelectric converter 6, and the first multi-port combiner 3 to form an upper closed loop. The upper core device 19 is connected to different baseband processing units 17 through the transmission network 18; one of the two outputs of the baseband processing unit 17 is connected to the first remote radio frequency unit 1, and the other is connected to the first redundant backup remote The radio frequency unit 11 ; one of the two outputs of the other baseband processing unit 17 is connected to the second remote radio frequency unit 2 , and the other is connected to the second redundant backup remote radio frequency unit 12 .

The baseband processing unit 17 generates a dual baseband MIMO signal, and simultaneously sends the generated dual MIMO signal to the first remote radio unit 1, the second remote radio unit 2, and the first redundant backup remote radio Unit 11, the second redundant backup remote radio unit 12; the baseband processing unit 17 sends the same two-way MIMO signal to the first remote radio unit 1 and the first redundant backup remote radio unit 11, the Another baseband processing unit 17 sends the second remote radio unit 2 and the second redundant backup remote radio unit 12 to be the same dual-channel MIMO signal; the function of the remote radio unit is to input the baseband processing unit 17 The two-way baseband signal is radio-frequency modulated and output in two ways; the first multi-port combiner 3 and the second multi-port combiner 13 are four-port combiners, and the third multi-port combiner 8 and the second multi-port combiner Four multi-port combiners 9 all possess three ports; the radio frequency electro-optic converter 4, the optical fiber 5, and the radio frequency photoelectric converter 6 are used to reduce the loss and transmission time delay of long-distance signal transmission, and the radio frequency electro-optic converter 4 The function of the radio frequency electrical signal is converted into an optical signal so that the optical fiber 5 can be transmitted, and the function of the radio frequency photoelectric converter 6 is to convert the optical signal into a radio frequency electrical signal; the function of the time delay compensation module 7 is to reduce the transmission time delay, and guarantee the orthogonality of the MIMO signal bidirectionally fed by the leaky cable. The value of time delay compensation in the time delay compensation module 7 is determined by the fixed time delay generated by the radio frequency electro-optic converter 4 , the optical fiber 5 and the radio frequency photoelectric converter 6 . The system meets the requirements of uplink communication at the same time, and the uplink data signal received by a single bidirectional leaky cable 10 can be received by the remote radio frequency unit through the time delay compensation module 7, the radio frequency photoelectric converter 6, the optical fiber 5, and the radio frequency electro-optic converter 4 . This application example is aimed at the wireless MIMO communication coverage scenario of rail transit, which reduces the number of leaky cables in the traditional dual leaky cable MIMO signal communication transmission system to one, and has efficient MIMO performance. It meets the needs of uplink and downlink communication, is suitable for frequency division duplex and time division duplex communication, can be used for MIMO signal coverage of rail transit communication systems, and supports multi-frequency redundant networking.

Figure 4 shows an example diagram of a dual-frequency redundant communication transmission system that uses MIMO signals bidirectionally fed into dual leaky cables for rail transit wireless communication. Not limited to the above-mentioned dual-frequency redundant networking situation, the communication transmission system can be expanded to a redundant backup structure of multiple remote radio frequency units, supporting multi-frequency redundant networking; not limited to the above-mentioned double leaky cable communication situation, all The communication transmission system can be extended to a MIMO communication structure of multiple leaky cables; the communication transmission system has a four-way MIMO transmission structure, and the MIMO mode is space division multiplexing;

The communication transmission system includes a first multi-channel remote radio frequency unit 14, a second multi-channel remote radio frequency unit 15, a first redundant backup multi-channel remote radio unit 20, a second redundant backup multi-channel remote radio frequency Unit 21, first multiport combiner 3, second multiport combiner 13, radio frequency electro-optic converter 4, optical fiber 5, radio frequency photoelectric converter 6, delay compensation module 7, third multiport looper 8 , a fourth multi-port circulator 9 , a single bidirectional leaky cable 10 , a second bidirectional leaky cable 16 , multiple baseband processing units 17 , a transmission network 18 , and an upper layer core device 19 . By the first multi-path remote radio frequency unit 14, the first multi-path redundant backup remote radio frequency unit 20, and the baseband processing unit 17 form the first base station end of the rail transit communication system; by the second multi-path remote Terminal radio frequency unit 15, the second multi-channel redundant backup far-end radio frequency unit 21, baseband processing unit 17 has formed the second base station end of rail transit communication system; Described single two-way leaky cable 10, the second two-way leaky cable 16 and The length of the optical fiber 5 is several hundred meters to several kilometers, and is laid between the two above-mentioned first base station ends and the second base station ends. The left end of the single bidirectional leakage cable 10 is connected to the output of the first multi-port combiner 3, and the right end is connected to the output of the second multi-port combiner 13; the output of the first multi-channel redundant backup remote radio frequency unit 20 is Among the four signals with frequency _f3 , one signal S _{3-1, f3} is sequentially connected to the delay compensation module 7 and the input of the first multi-port combiner 3, and the other signal S _{3-2, f3} is connected to the third multi-port The input of the port combiner 8; the first multi-channel remote radio frequency unit 14 outputs one signal S _1-1 in the four-channel signal whose frequency is f ₁ , and f1 is connected to the time delay compensation module 7 and the first multi-port in turn The input of the combiner 3, another road signal S _{1-2, f1} is connected to the input of the third multiport combiner 8; the output of the fourth multiport combiner 9 is sequentially connected to the radio frequency electro-optic converter 4, the optical fiber 5 , RF photoelectric converter 6, the first multi-port combiner 3, forming the first upper closed loop; the second multi-channel redundant backup remote radio frequency unit 21 output frequency is one of the _four signals of f4 The signal S _{4-2, f4} is connected to the input of the delay compensation module 7 and the second multi-port combiner 13 in turn, and the other signal S _{4-1, f4} is connected to the input of the fourth multi-port combiner 9; the first Two multi-channel remote radio frequency unit 15 outputs one channel signal S _2-2 in the four-channel signal whose frequency is _{f2, and f2} is sequentially connected to the input of delay compensation module 7 and the second multi-port combiner 13, and the other channel signal S _{2-1, f2} is connected to the input of the fourth multiport combiner 9; the output of the third multiport combiner 8 is connected to the radio frequency electro-optic converter 4, the optical fiber 5, the radio frequency photoelectric converter 6, and the second multiport The combiner 13 forms a first lower closed loop. The other two signals S _{1-3, f1} , S _{1-4, f1} output by the first multi-channel remote radio frequency unit 14 and the other two signals S ₂ output by the second multi-channel remote radio frequency unit 15 _{-3, f2} , S _{2-4, f2} forms a second upper closed loop and a second lower closed loop with the second bidirectional leaky cable 16 according to the above-mentioned connection mode of the lower closed loop and the upper closed loop; A multi-channel redundant backup remote radio frequency unit 20 outputs one signal S3-3 in the four-channel signal whose frequency is _{f3 , and f3} is sequentially connected to the input of the delay compensation module 7 and the first multi-port combiner 3, and the other One signal S _{3-4, f3} is connected to the input of the third multi-port combiner 8; the second multiple redundant backup remote radio frequency unit 21 outputs one signal S _4- of the _four signals with frequency f4 _{4, f4} is sequentially connected to the delay compensation module 7 and the input of the second multi-port combiner 13, and another signal S _{4-3, f4} is connected to the input of the fourth multi-port combiner 9; the upper layer core device 19 passes The transmission network 18 is connected to different baseband processing units 17; one of the two outputs of the baseband processing unit 17 is connected to the first multi-channel remote radio frequency unit 14, and the other is connected to the first multi-channel redundant backup remote radio frequency unit 20 One of the two outputs of the other baseband processing unit 17 is connected to the second multi-channel remote radio frequency unit 15, and the other is connected to the second multi-channel redundant backup remote radio frequency unit 21.

The four baseband MIMO signals generated by the baseband processing unit 17 are sent to the first multi-channel remote radio frequency unit 14, the second multi-channel remote radio frequency unit 15, and the first multi-channel MIMO signal simultaneously. The redundant backup remote radio unit 20, the second multi-channel redundant backup remote radio unit 21; the baseband processing unit 17 sends the first multi-channel remote radio unit 14 and the first multi-channel redundant backup remote radio The unit 20 is the same four-way MIMO signal, and the other baseband processing unit 17 sends the same four-way MIMO signal to the second multi-way remote radio unit 15 and the second multi-way redundant backup remote radio unit 21; The function of the remote radio frequency unit is to carry out radio frequency modulation and two-way output of the four baseband signals input by the baseband processing unit 17; the first multi-port combiner 3 and the second multi-port combiner 13 are equipped with four port, the third multiport combiner 8 and the fourth multiport combiner 9 all have three ports; the radio frequency electro-optic converter 4, the optical fiber 5, and the radio frequency photoelectric converter 6 are used to reduce long-distance transmission of signals loss and transmission time delay, the effect of the radio frequency electro-optic converter 4 is to convert the electrical signal of the radio frequency into an optical signal, so that the optical fiber 5 transmits, and the effect of the radio frequency photoelectric converter 6 is to convert the optical signal into a radio frequency electrical signal; The function of the time delay compensation module 7 is to reduce the transmission time delay and ensure the orthogonality of the MIMO signal bidirectionally fed by the leakage cable; the value of the time delay compensation in the time delay compensation module 7 is determined by the radio frequency electro-optic 4. The fixed time delay generated by the optical fiber 5 and the radio-frequency photoelectric converter 6 is determined; the single bidirectional leaky cable 10 and the second bidirectional leaky cable 16 maintain a sufficient distance to ensure that the single bidirectional leaky cable 10 and the first bidirectional leaky cable The irrelevance between the radiated signals of the two bidirectional leaky cables 16 achieves efficient MIMO performance; the system meets the requirements of uplink communication at the same time, and the uplink data signals received by the single bidirectional leaky cable 10 and the second bidirectional leaky cable 16 can pass through The delay compensation module 7, the radio frequency photoelectric converter 6, the optical fiber 5, and the radio frequency electro-optical converter 4 are received by the remote radio unit. This application example is aimed at the wireless MIMO communication coverage scenario of rail transit, which reduces the number of leaky cables in the traditional four leaky cable MIMO signal communication transmission system by half, and has efficient MIMO performance. It meets the needs of uplink and downlink communication, is suitable for frequency division duplex and time division duplex communication, can be used for MIMO signal coverage of rail transit communication systems, and supports multi-frequency redundant networking.

Claims (3)

1. A rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables, characterized in that it includes a first remote radio frequency unit (1), a second remote radio frequency unit (2), and a first multi-port combination device (3), second multiport combiner (13), radio frequency electro-optic converter (4), optical fiber (5), radio frequency photoelectric converter (6), delay compensation module (7), third multiport combiner (8), a fourth multi-port combiner (9), a single bidirectional leaky cable (10), at least one first redundant backup remote radio frequency unit (11), at least one second redundant backup remote A radio frequency unit (12); the left end of the single bidirectional leakage cable (10) is connected to the output of the first multi-port combiner (3), and the right end is connected to the output of the second multi-port combiner (13); the second A remote radio frequency unit (1) outputs two-way signals with frequency f1. One signal is connected to the delay compensation module (7) and the input of the first multi-port combiner (3) in turn, and the other signal is connected to the third multi-port The input of the combiner (8); one of the two-way signals output by one or more of the first redundant backup remote radio frequency units (11) is sequentially connected to the delay compensation module (7) and the first multi-port combiner The input of the device (3), the other is connected to the input of the third multi-port combiner (8); the output of the third multi-port combiner (8) is sequentially connected to the radio frequency electro-optic converter (4), the optical fiber (5 ), a radio frequency photoelectric converter (6), and a second multi-port combiner (13), forming a lower closed loop; the second remote radio frequency unit (2) outputs one signal of the two-way signal with frequency f2 in turn Connect the delay compensation module (7) and the input of the second multi-port combiner (13), and another signal is connected to the input of the fourth multi-port combiner (9); one or more of the second redundant backup One of the two-way signals output by the remote radio frequency unit (12) is sequentially connected to the delay compensation module (7) and the input of the second multi-port combiner (13), and the other is connected to the fourth multi-port combiner (9) input; the output of the fourth multiport combiner (9) is sequentially connected to the radio frequency electro-optic converter (4), the optical fiber (5), the radio frequency photoelectric converter (6), and the first multiport combiner (3) , forming an upper closed loop. 2. The rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables according to claim 1, characterized in that it also includes a plurality of single bidirectional leaky cables (10), the first multi-channel remote radio frequency unit ( 14), the second multi-channel remote radio frequency unit (15); the first multi-channel remote radio frequency unit (14) and the second multi-channel remote radio frequency unit (15) include multiple radio frequency output ports, and the multi-channel radio frequency The signal output by the output port is a multi-channel data signal that satisfies the orthogonality between signals, or has a multi-channel data signal that can be separated by the receiver; multiple upper closed loops and lower closed loops are connected in a first multiple On the remote radio frequency unit (14) and the second multi-channel remote radio frequency unit (15), a sufficient distance is set between the single bidirectional leakage cables (10) on each loop to keep different single bidirectional leakage cables ( 10) Uncorrelation between radiation signals. 3. The rail transit wireless MIMO communication transmission system in which signals are bidirectionally fed into leaky cables according to claim 1, further comprising one or more first multi-channel redundant backup remote radio frequency units (20), the second Two multiple redundant backup remote radio frequency units (21); one signal in each dual signal of the multiple data signals output by the one or more first multiple redundant backup remote radio units (20) in sequence Connect the delay compensation module (7) to the input of the first multi-port combiner (3), and connect another signal to the third multi-port combiner (8); the one or more second multiplex redundant backups Among the multiple data signals output by the remote radio frequency unit (21), one signal of each two-channel signal is sequentially connected to the delay compensation module (7) and the input of the second multi-port combiner (13), and the other signal is connected to A fourth multiport combiner (9).