CN113301615B - GSM-R handover method based on multi-source information fusion train positioning - Google Patents

Abstract

The invention discloses a GSM-R handover method based on multi-source information fusion train positioning, which introduces a Beidou-based multi-source information fusion train positioning technology into a GSM-R handover judgment mechanism and provides a GSM-R handover method suitable for a high-speed railway.

Description

GSM-R handover method based on multi-source information fusion train positioning

Technical Field

The invention relates to the field of railway communication, in particular to a GSM-R handover method based on multi-source information fusion train positioning.

Background

The railway in China starts to carry out the GSM-R technical system since 2002, and realizes the gradual and orderly transition of the railway wireless communication base platform from the 450MHz analog wireless train dispatching system to the GSM-R system. At present, the high-speed railways at home and abroad mostly adopt GSM-R as the main technology of the train-ground wireless communication system, and in the future, the GSM-R is still the dominant railway mobile communication system. The GSM-R system is used as an important means for guaranteeing the safe production of railway transportation, effectively improves the transportation efficiency and plays a great role in the economic and social development. The comprehensive bearing service, especially train control information transmission, has high requirements on quality of service (QoS), such as transmission reliability and real-time performance.

The running speed of high-speed railways in China is 300-350 km/h currently, and along with the increase of the running mileage of high-speed railways and the formation of high-speed railway networks, the requirement of improving the highest running speed is also increasing. The handover is classified into normal handover, emergency handover, load handover, fast movement handover, concentric handover, etc. according to the condition of handover trigger, and the current train decides whether to perform the handover mainly by detecting the received cell signal strength and signal quality. However, the improvement of the moving speed of the train causes a certain change of the radio wave propagation characteristics, especially the influence of the Doppler effect is further increased, the larger Doppler frequency shift causes signal distortion, the communication quality is deteriorated, the channel is caused to have obvious time-varying characteristics, and the performance of processing algorithms such as channel estimation, equalization and the like is further deteriorated. The degradation of the channel condition directly causes the decrease of SINR (Signal to Interference plus Noise Ratio ) value, the rapid change of wireless signal receiving intensity and the like, which affects the judgment condition of the handover, possibly causes the poor handover position, and causes the terminal to lose connection with the service cell before the handover is not finished, thereby generating service interruption; or because the triggering condition of the handover is unreasonable, the ping-pong handover is generated, thereby affecting the service quality of the GSM-R system and seriously affecting the normal communication between vehicles and places. Thus, there is a need to develop a more reliable train location based GSM-R handoff method.

The high-speed rail in current operation mainly comprises the steps of dividing a section, constructing a track circuit by taking a railway rail as a conductor to judge the occupation condition of the railway section, and reading information of a line positioning reference transponder (LRBG for short) by a vehicle-mounted transponder reader to realize the position and speed measurement of a train. The positioning accuracy of the method cannot meet the requirement of auxiliary handover. With the third generation Beidou navigation satellite system (BeidouNavigation Satellite System) completing global coverage in 2020, the real-time performance, reliability and convenience of satellite positioning are greatly improved. However, the high-speed train has high running speed and complex positioning scene, and the precision can not meet the requirement when only a commercial Beidou positioning system is used for positioning the train. Meanwhile, when the train moves at a high speed, the Doppler effect generated by the relative motion of the satellite and the high-speed train (comprising the rotation of the satellite relative to the earth and the translation of the satellite relative to the train) generates frequency offset, so that the carrier frequency of satellite navigation signals is seriously influenced, and the positioning precision is reduced. The high-speed rail is easily affected by weather, electromagnetic interference, buildings and other factors in the running process, and the accuracy of satellite signal positioning can be obviously reduced. Therefore, it is necessary to study a stable high-speed train accurate positioning method to support the GSM-R handover method based on the train position.

Disclosure of Invention

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a GSM-R handover method based on multi-source information fusion train positioning that overcomes or at least partially solves the above problems.

In order to solve the technical problems, the embodiment of the application discloses the following technical scheme:

the embodiment discloses a GSM-R handover method based on multi-source information fusion train positioning, which comprises the following steps:

s100, determining an optimal switching position as a reference switching position according to all-line field intensity coverage test data and service quality test data;

s200, fusing the multi-source information to obtain train positioning information;

s300, the mobile station measures the downlink received signal level and quality of the current cell and the received signal strength information from surrounding cells;

s400, the mobile station generates a measurement report message and sends the measurement report message to a base station where the mobile station is currently located, the content of the measurement report is modified, and the position information and the speed information of the train are added in the measurement report reported by the train mobile station;

s500, the base station monitors the uplink receiving level and quality of each served mobile station, generates a measurement report, and sends the measurement report and the measurement result of the mobile station to the base station controller;

s600, the base station controller combines the reference switching position, the real-time measured train position and the running speed according to the measurement results reported by the mobile station and the base station, assists the switching starting mechanism to make a decision, optimizes the switching position and performs switching;

s700, if the handover is judged to be needed, the base station controller performs handover triggering, sends a channel activation message to the new cell, requires the new cell to provide a TCH channel for receiving handover, and if the new cell provides an idle TCH, sends back a confirmation character message to the base station controller;

s800, the base station controller sends a switching command message to the current base station through FACCH, and the current base station sends the command to the mobile station;

s900, the mobile station adjusts the frequency to a new frequency, and then sends a switching access burst pulse to a new cell through a FACCH channel;

s1000, after receiving the burst pulse, the new base station returns time advance information to the mobile station through the FACCH;

s1100, the mobile station sends switching completion information to a base station controller through a new base station;

s1200, the base station controller informs the original base station of releasing the TCH channel.

Further, S200 specifically includes:

s201, continuously receiving Beidou satellite signals in the running process of the train, and acquiring high-speed train coordinate data through the Beidou satellite signals;

s202, judging the occupation condition of a railway section of the train by utilizing a track circuit, reading data of a positioning reference transponder along the line by a vehicle-mounted transponder reader, and calibrating the accumulated error of the train position;

s203, current train running data are measured through wheel sensors, and the relative displacement of the train is calculated through counting the number of wheel revolutions;

s204, the multisource information fusion positioning system fuses the Beidou positioning data, the track circuit occupation information, the vehicle-mounted transponder reader acquired along-line positioning reference information, the wheel sensor information and other information;

s205, carrying out linearization analysis on the motion states of the trains at a plurality of moments, realizing the joint estimation of the train positions, ensuring that the trains always obtain reliable positioning results in a changeable environment, reducing the positioning errors of the high-speed trains and obtaining high-precision positioning coordinates.

Further, in S400, the mobile station transmits a measurement report message to the base station where it is currently located, once every multiframe space time over SACCH.

Further, in S600, the starting mechanism decision specifically includes:

s601, calculating a handover optimal interval according to the train speed and a reference handover position, wherein the handover optimal interval is defined as [ X+/-vt, X ], wherein X is the reference handover position, v is the train speed, t is the time of one-time handover, and when the running direction is the large mileage direction, the number is subtracted; when the running direction is the small mileage direction, a plus sign is taken;

s602, if the field intensity of the current cell is measured to be weakened, the field intensity of the target cell is measured to be strengthened, the signal intensity or the signal quality of the target base station reaches a preset threshold, and meanwhile, the position of the train relative to the current base station and the target base station is in a switching optimal interval, triggering the handover, otherwise, not triggering the handover.

Further, in S600, the starting mechanism decision specifically further includes: s603, triggering the handover if the signal strength does not reach the handover threshold value, but the train position reaches the handover optimal interval threshold value, namely the reference handover position.

Further, in S800, the handover command message includes at least: frequency, time slot and transmit power parameters of the new channel.

Further, the GSM-R handover method based on multi-source information fusion train positioning further comprises the following steps:

s1300, if the switching is unsuccessful, returning to the original channel, and continuing to judge until the mobile station can reside in the cell meeting the requirement.

The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:

the invention discloses a GSM-R handover method based on multi-source information fusion train positioning, which introduces a Beidou-based multi-source information fusion train positioning technology into a GSM-R handover judgment mechanism and provides a GSM-R handover method suitable for a high-speed railway.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:

fig. 1 is a flowchart of a GSM-R handover method based on multi-source information fusion train positioning in embodiment 1 of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In order to solve the problems in the prior art, the embodiment of the invention provides a GSM-R handover method based on multi-source information fusion train positioning.

Example 1

A GSM-R handover method based on multi-source information fusion train positioning, as shown in figure 1, comprises the following steps:

s100, determining an optimal switching position as a reference switching position according to all-line field intensity coverage test data and service quality test data;

s200, fusing the multi-source information to obtain train positioning information; specifically, in this embodiment, the multi-source information is fused to obtain the train positioning information, which specifically includes:

s201, continuously receiving Beidou satellite signals in the running process of the train, and acquiring high-speed train coordinate data through the Beidou satellite signals;

s202, judging the occupation condition of a railway section of the train by utilizing a track circuit, reading data of a positioning reference transponder along the line by a vehicle-mounted transponder reader, and calibrating the accumulated error of the train position;

s203, current train running data are measured through wheel sensors, and the relative displacement of the train is calculated through counting the number of wheel revolutions;

s204, the multisource information fusion positioning system fuses the Beidou positioning data, the track circuit occupation information, the vehicle-mounted transponder reader acquired along-line positioning reference information, the wheel sensor information and other information;

s205, carrying out linearization analysis on the motion states of the trains at a plurality of moments, realizing the joint estimation of the train positions, ensuring that the trains always obtain reliable positioning results in a changeable environment, reducing the positioning errors of the high-speed trains and obtaining high-precision positioning coordinates.

S300, the mobile station measures the downlink received signal level and quality of the current cell and the received signal strength information from surrounding cells.

S400, the mobile station generates a measurement report message and sends the measurement report message to the base station where the mobile station is currently located, the content of the measurement report is modified, and the train position information and the speed information of the train are added in the measurement report reported by the train mobile station. In this embodiment, the mobile station sends a measurement report message to the currently located base station every multiframe space time over SACCH.

S500, the base station monitors the uplink receiving level and quality of each served mobile station, generates a measurement report, and sends the measurement report and the measurement result of the mobile station to the base station controller;

s600, the base station controller combines the reference switching position, the real-time measured train position and the running speed according to the measurement results reported by the mobile station and the base station, assists the switching starting mechanism to make a decision, optimizes the switching position and performs the switching.

In this embodiment S600, the startup mechanism decision specifically includes:

s601, calculating a handover optimal interval according to the train speed and a reference handover position, wherein the handover optimal interval is defined as [ X+/-vt, X ], wherein X is the reference handover position, v is the train speed, t is the time of one-time handover, and when the running direction is the large mileage direction, the number is subtracted; when the running direction is the small mileage direction, a plus sign is taken;

s602, if the field intensity of the current cell is measured to be weakened, the field intensity of the target cell is measured to be strengthened, the signal intensity or the signal quality of the target base station reaches a preset threshold, and meanwhile, the position of the train relative to the current base station and the target base station is in a switching optimal interval, triggering the handover, otherwise, not triggering the handover.

In some preferred embodiments, the initiating the mechanism decision, in particular further comprises: s603, triggering the handover if the signal strength does not reach the handover threshold value, but the train position reaches the handover optimal interval threshold value, namely the reference handover position.

S700, if the handover is judged to be needed, the base station controller performs handover triggering, sends a channel activation message to the new cell, requires the new cell to provide a TCH channel for receiving handover, and if the new cell provides an idle TCH, sends back a confirmation character message to the base station controller;

s800, the base station controller sends a switching command message to the current base station through FACCH, and the current base station sends the command to the mobile station;

s900, the mobile station adjusts the frequency to a new frequency, and then sends a switching access burst pulse to a new cell through a FACCH channel;

s1000, after receiving the burst pulse, the new base station returns time advance information to the mobile station through the FACCH;

s1100, the mobile station sends switching completion information to a base station controller through a new base station;

s1200, the base station controller informs the original base station of releasing the TCH channel.

In some preferred embodiments, a GSM-R handoff method based on multi-source information fusion train positioning further comprises:

s1300, if the switching is unsuccessful, returning to the original channel, and continuing to judge until the mobile station can reside in the cell meeting the requirement.

According to the GSM-R handover method based on multi-source information fusion train positioning, a Beidou-based multi-source information fusion train positioning technology is introduced into a GSM-R handover judgment mechanism, and the GSM-R handover method suitable for high-speed railways is provided.

It should be understood that the specific order or hierarchy of steps in the processes disclosed are examples of exemplary approaches. Based on design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate preferred embodiment of this invention.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. The processor and the storage medium may reside as discrete components in a user terminal.

For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. These software codes may be stored in memory units and executed by processors. The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

The foregoing description includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, as used in the specification or claims, the term "comprising" is intended to be inclusive in a manner similar to the term "comprising," as interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean "non-exclusive or".

Claims (6)

1. The GSM-R handover method based on multi-source information fusion train positioning is characterized by comprising the following steps:

s100, determining an optimal switching position as a reference switching position according to all-line field intensity coverage test data and service quality test data;

s200, fusing the multi-source information to obtain train positioning information; s200 specifically comprises:

s201, continuously receiving Beidou satellite signals in the running process of the train, and acquiring high-speed train coordinate data through the Beidou satellite signals;

s202, judging the occupation condition of a railway section of the train by utilizing a track circuit, reading data of a positioning reference transponder along the line by a vehicle-mounted transponder reader, and calibrating the accumulated error of the train position;

s203, current train running data are measured through wheel sensors, and the relative displacement of the train is calculated through counting the number of wheel revolutions;

s204, the multisource information fusion positioning system fuses the Beidou positioning data, the track circuit occupation information, the vehicle-mounted transponder reader acquired along-line positioning reference information, the wheel sensor information and other information;

s205, carrying out linearization analysis on the motion states of the trains at a plurality of moments, realizing joint estimation of the train positions, ensuring that the trains always obtain reliable positioning results in a changeable environment, reducing positioning errors of the high-speed trains and obtaining high-precision positioning coordinates;

s300, the mobile station measures the downlink received signal level and quality of the current cell and the received signal strength information from surrounding cells;

s400, the mobile station generates a measurement report message and sends the measurement report message to a base station where the mobile station is currently located, the content of the measurement report is modified, and the position information and the speed information of the train are added in the measurement report reported by the train mobile station;

s500, the base station monitors the uplink receiving level and quality of each served mobile station, generates a measurement report, and sends the measurement report and the measurement result of the mobile station to the base station controller;

s600, the base station controller combines the reference switching position, the real-time measured train position and the running speed according to the measurement results reported by the mobile station and the base station, assists the switching starting mechanism to make a decision, optimizes the switching position and performs switching;

s700, if the handover is judged to be needed, the base station controller performs handover triggering, sends a channel activation message to the new cell, requires the new cell to provide a TCH channel for receiving handover, and if the new cell provides an idle TCH, sends back a confirmation character message to the base station controller;

s800, the base station controller sends a switching command message to the current base station through FACCH, and the current base station sends the command to the mobile station;

s900, the mobile station adjusts the frequency to a new frequency, and then sends a switching access burst pulse to a new cell through a FACCH channel;

s1000, after receiving the burst pulse, the new base station returns time advance information to the mobile station through the FACCH;

s1100, the mobile station sends switching completion information to a base station controller through a new base station;

s1200, the base station controller informs the original base station of releasing the TCH channel.

2. A GSM-R handover method based on multisource information fusion train positioning according to claim 1, characterized in that in S400 the mobile station sends a measurement report message to the currently located base station on SACCH every multiframe space time.

3. The GSM-R handover method based on multi-source information fusion train positioning of claim 1, wherein in S600, the starting mechanism decision specifically comprises:

s601, calculating a handover optimal interval according to the train speed and a reference handover position, wherein the handover optimal interval is defined as [ X+/-vt, X ], wherein X is the reference handover position, v is the train speed, t is the time of one-time handover, and when the running direction is the large mileage direction, the number is subtracted; when the running direction is the small mileage direction, a plus sign is taken;

s602, if the field intensity of the current cell is measured to be weakened, the field intensity of the target cell is measured to be strengthened, the signal intensity or the signal quality of the target base station reaches a preset threshold, and meanwhile, the position of the train relative to the current base station and the target base station is in a switching optimal interval, triggering the handover, otherwise, not triggering the handover.

4. The GSM-R handover method based on multi-source information fusion train positioning according to claim 1, wherein in S600, the starting mechanism decision, specifically further comprises: s603, triggering the handover if the signal strength does not reach the handover threshold value, but the train position reaches the handover optimal interval threshold value, namely the reference handover position.

5. A GSM-R handoff method based on multi-source information fusion train positioning according to claim 1, wherein in S800, the handoff command message comprises at least: frequency, time slot and transmit power parameters of the new channel.

6. A GSM-R handoff method based on multi-source information fusion train positioning according to claim 1, further comprising:

s1300, if the switching is unsuccessful, returning to the original channel, and continuing to judge until the mobile station can reside in the cell meeting the requirement.

Images