Urban rail transit LTE-M network system and fault monitoring method

Abstract

The invention discloses an urban rail transit LTE-M network system and a fault monitoring method. The system comprises an LTE network layer and a vehicle-mounted access layer, the LTE network layer comprises an A core network, a B core network, base station equipment and a combiner. Transmission data is transmitted to the combiner through the dual-core network and the base station device. The vehicle-mounted access layer comprises a TAU arranged on a train and used for data transmission between a train and a dual-core network. More than two TAUs are respectively arranged in a head carriage anda tail carriage of the train, a part of TAUs in each carriage are connected with one core network, the other part of TAUs in each carriage are connected with the other core network, and parallel datatransmission is carried out between each TAU in each carriage and the dual-core network. The method has the advantages that the structure is simple, the cost is low, the redundancy is high, single-point faults such as a combiner can be reduced, the influence on train operation under the extreme network fault working condition is reduced, and safety and reliability are achieved.

Description

technical field [0001] The invention relates to the technical field of urban rail transit communication, in particular to an urban rail transit LTE-M network system and a fault monitoring method. Background technique [0002] LTE (Long Term Evolution, Long Term Evolution) is a long-term evolution wireless communication technology, its goal is to establish a high transmission rate, low delay, support for enhanced multimedia broadcast multicast service (e-MBMS), based on optimization An evolvable wireless access architecture, LTE-M is a TD-LTE system aimed at the comprehensive service bearing requirements of urban rail transit, to meet the application requirements of urban rail transit interconnection and information transmission integrated service bearer. The LTE-M system works in the dedicated frequency band of 1785MHz to 1805MHz to meet the needs of urban rail transit vehicle-to-ground communication services. On the basis of ensuring the communication-based train control sy...

AI Technical Summary

Problems solved by technology

[0006] (1) Single point failures such as combiners cannot be avoided

Since the RRUs of different networks are fed into the leaky cable after being combined by a combiner, if the combiner fails, or the jumper connecting the combiner and the RRU fails, or the corresponding joint is damaged due to construction technology or other cleaning operations Waterproof damage or loose joint failures will cause abnormal standing waves or even wireless link interruptions. Since the data of the A / B network is combined into the leaky coaxial cable by a combiner at the same time through a combiner, the combined In a very long section where the router is the midpoint, there will be a wireless coverage blind area, that is, the A / B dual network has no wireless signal in this area and there will be a short-term interruption, and because only one TAU is installed at the front and rear of the train , the front and rear of the train can only access the data of one network respectively. When the train passes through the coverage blind zone, the network interruption of the front TAU ​​will occur, resulting in a long-term interruption of the wireless communication between the train and the ground. The community obtains the data of one network, which cannot guarantee the reliable communication of the train

[0007] (2) When one of the LTE-M redundant dual networks fails completely and the RRU of the other network fails, the coverage blind area of ​​the entire cell will also appear. When the TAU is connected to the B network, when the A network fails and a RRU in the B network fails, the TAU at the front of the vehicle will experience continuous network interruption, and when the rear of the vehicle passes through the coverage area of ​​the faulty RRU, the network will also be interrupted, causing long-term wireless communication between the vehicle and the ground. If the network is disconnected in time, the communication link will be interrupted, which may even lead to emergency shutdown

[0008] (3) Low reliability in scenarios such as fully automatic driving

In the unmanned driving scenario, after the train is dormant, since the wake-up command can only be transmitted from one end through the on-board TAU, and the switch connected to the head and tail TAU of the vehicle is not powered in this mode, if the wake-up TAU fails, it will directly Affect the efficiency of the fully automatic operation of the vehicle, and even affect the normal entry and exit of the vehicle and the main line operation

[0009] To sum up, when a single point of failure occurs in the existing LTE-M system (such as the above-mentioned combiner failure, complete failure of one network and RRU single point failure of the other network, etc.), the network will be interrupted for a long time. , and problems such as low reliability in fully automatic driving scenarios

If the leaky cables are overlapped at the trackside RRU, the length of the radio frequency jumper will be very long, resulting in a large signal attenuation, and it is not conducive to construction, and the feasibility is poor

[0010] In order to improve the reliability of the vehicle-to-ground wireless network, some practitioners have proposed further redundancy settings based on the LET-M dual-network redundancy, but these are usually designed for the redundancy of the vehicle-to-ground wireless network architecture, or to the vehicle-to-ground wireless network architecture. Redundancy of signal and system equipment, PIS service transmission channels, etc. For example, Chinese patent application 201110414160.7 discloses a multiple redundant processing method for vehicle-to-ground data transmission in rail transit, which is to directly perform redundant configuration for WLAN networks. This type of redundant setting The method still cannot solve the above-mentioned problems of single point of failure, reliability in fully automatic driving scenarios, etc.

If you directly consider setting up redundant units for the TAUs in the train, the way of setting up backup equipment is usually adopted, that is, one TAU is used as the main TAU and the other is used as the backup TAU. When the main TAU fails, the backup TAU is activated, but the backup TAU is used. , the front and rear of the car can still only access the data of one network respectively, and still cannot solve the above-mentioned single point of failure problem and low reliability in fully automatic driving scenarios.

Images