CN108964738B - Vehicle-mounted antenna system for rail transit vehicle-ground wireless system - Google Patents
Vehicle-mounted antenna system for rail transit vehicle-ground wireless system Download PDFInfo
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- CN108964738B CN108964738B CN201810720052.4A CN201810720052A CN108964738B CN 108964738 B CN108964738 B CN 108964738B CN 201810720052 A CN201810720052 A CN 201810720052A CN 108964738 B CN108964738 B CN 108964738B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0805—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching
- H04B7/0808—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching comparing all antennas before reception
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0805—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching
- H04B7/0814—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with single receiver and antenna switching based on current reception conditions, e.g. switching to different antenna when signal level is below threshold
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0834—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection based on external parameters, e.g. subscriber speed or location
Abstract
The invention relates to the field of train wireless communication, and particularly discloses a vehicle-mounted antenna system for a rail transit train-ground wireless system, which comprises the following components: the vehicle-mounted antenna module is provided with a plurality of pairs of vehicle-mounted antennas arranged on the train; the signal detection module is used for periodically acquiring the received signal strength of each vehicle-mounted antenna; the train positioning system is used for acquiring a geographical coordinate signal of a train; the setting module is used for configuring a signal detection mode; the antenna selection module is used for selecting the corresponding vehicle-mounted antenna for communication according to the configured mode; the vehicle-mounted combiner is used for respectively controlling the on-off of the plurality of auxiliary vehicle-mounted antennas; and the connection control module is used for controlling the vehicle-mounted combiner to be switched to the selected vehicle-mounted antenna to be accessed into the vehicle-mounted access unit according to the vehicle-mounted antenna selected by the antenna selection module. The invention can select the optimal antenna or the optimal antenna combination for receiving and transmitting the wireless signals, improves the signal quality of the vehicle-mounted access unit, and improves the data transmission rate and the performance of the whole vehicle-ground wireless system.
Description
Technical Field
The invention belongs to the field of train wireless communication, and particularly relates to a vehicle-mounted antenna system for a rail transit train-ground wireless system.
Background
In rail transit, a train in operation needs to transmit data with the ground, and the method comprises the following steps: train control signal service, emergency text, train status information, video surveillance, passenger information systems, and vehicle-mounted fire information, among others. And the train and the ground data transmission is realized through a train-ground wireless system. In 2016, a train-ground wireless system is generally built by adopting a WLAN technology, and with the application of a TD-LTE wireless mobile communication technology in an industrial market and the distribution of private network frequency, a train-ground wireless system is built by adopting the TD-LTE technology on a newly-built rail transit line after 2016.
In rail transit, some lines are all underground lines, and some lines are composed of underground sections and ground sections. Due to the characteristics of the track, the train-ground wireless system is not suitable for covering the track by adopting the antenna, and generally adopts the leaky cable to cover the track, so that the leaky cable has the characteristics of small loss, suitability for linear deployment and the like.
The underground tunnel is generally provided with the leaky cable at the top of the tunnel and at the position with the height consistent with that of the roof of the tunnel, and the leaky cable at the overhead section of the ground is generally arranged at the position close to the bottom of the vehicle.
When the mounting positions of the leaky cable of the underground tunnel and the ground elevated section are inconsistent, antennas need to be simultaneously mounted on the roof and two sides of the train. If only a roof antenna is installed on a train, a leaky cable needs to be erected to be 3.8 meters above a rail surface in an overhead section, and the implementation is difficult, so that a train side antenna is used in the overhead section. In addition, the train still needs to turn back in the operation process, so the antenna must be installed on the left side and the right side of the train. Generally, shark fin antennas (two pairs of shark fin antennas) are installed on the roof of a vehicle, dual-polarized panel antennas are installed on two sides of the vehicle, and then signals of the three antennas are combined through a vehicle-mounted combiner and then connected to a vehicle-mounted access unit (TAU).
However, the above antenna design has the following problems:
firstly, the vehicle-mounted antenna combiner is a passive device, a 2-layer combiner (as shown in fig. 1) needs to be designed in the existing scheme, the loss is large, the attenuation of the whole vehicle-mounted antenna combiner reaches 7-8dB, namely 80% of wireless signals pass through the vehicle-mounted antenna combiner and are wasted, and useful signals are only 20%.
When the train is underground, the roof antenna is close to the leaky cable and is mainly used for receiving and transmitting signals through the roof antenna; the signals transmitted by the antennas on both sides of the vehicle are wasted and interference signals are also received.
When the train is on the ground, the antenna on one side of the train is close to the leaky cable, signals are received and transmitted mainly through the antenna on one side, signals transmitted by the antenna on the other side and the roof antenna are wasted, and interference signals can be received.
Disclosure of Invention
The invention aims to provide a vehicle-mounted antenna system for a rail transit vehicle-ground wireless system, so that the defects that the relative position of a train and a leaky cable is uncertain and the power of signals is lost when a multi-surface antenna transmits or receives simultaneously are overcome.
To achieve the above object, the present invention provides a vehicle-mounted antenna system for a rail transit vehicle-ground wireless system, comprising:
the vehicle-mounted antenna module is provided with a plurality of pairs of vehicle-mounted antennas arranged on the train;
the signal detection module is connected with the vehicle-mounted antenna module and is used for periodically acquiring the received signal strength of each pair of vehicle-mounted antennas in the vehicle-mounted antenna module;
the train positioning system is used for acquiring a corresponding geographic coordinate signal and sending the geographic coordinate signal to the antenna selection module when a train passes through a preset geographic coordinate point according to the preset geographic coordinate point;
the device comprises a setting module, a signal detection module, a geographic coordinate detection module and a comprehensive detection module, wherein the setting module is used for configuring one of a signal detection mode, a geographic coordinate detection mode and a comprehensive detection mode;
the antenna selection module is respectively connected with the setting module, the signal detection module and the train positioning system, and selects the current specific vehicle-mounted antenna according to the detection mode configured by the setting module;
the vehicle-mounted combiner is respectively connected with the plurality of pairs of vehicle-mounted antennas and the vehicle-mounted access unit and is used for respectively controlling the on-off of the plurality of pairs of vehicle-mounted antennas; and
and the connection control module is respectively connected with the antenna selection module and the vehicle-mounted combiner and is used for controlling the vehicle-mounted combiner to switch the selected vehicle-mounted antenna to be accessed into the vehicle-mounted access unit according to the vehicle-mounted antenna selected by the antenna selection module.
Preferably, in the above technical solution, the module is configured to set a periodic interval measured by the signal detection module.
Preferably, in the above technical scheme, an antenna switching trigger point is set according to geographical position characteristics along the train track, and when the train passes through the antenna switching trigger point of the train track, the train positioning system sends the corresponding geographical coordinate signal to the antenna selection module.
Preferably, in the above technical solution, when the setting module configures a signal detection mode, the antenna selection module selects the vehicle-mounted antenna with the strongest signal detected by the signal detection module.
Preferably, in the above technical solution, when the setting module configures a geographic coordinate detection mode, the antenna selection module acquires a corresponding vehicle-mounted antenna according to the geographic coordinate signal.
Preferably, in the above technical solution, when the setting module configures the comprehensive detection mode, the antenna selection module compares the vehicle-mounted antenna with the strongest signal detected by the signal detection module with the vehicle-mounted antenna obtained according to the geographic coordinate signal, and selects the vehicle-mounted antenna with the strongest signal detected by the signal detection module when the vehicle-mounted antenna and the vehicle-mounted antenna are consistent, and selects the vehicle-mounted antenna corresponding to the geographic coordinate signal when the vehicle-mounted antenna and the vehicle-mounted antenna are inconsistent.
Preferably, in the above technical solution, the antenna selection module selects a pair of vehicle-mounted antennas with the strongest signals as the working antennas at that time.
Preferably, in the foregoing technical solution, when configuring a signal detection mode or a comprehensive detection mode, the step of selecting, by the antenna selection module, according to the received signal strengths of the multiple pairs of vehicle-mounted antennas sent by the signal detection module includes:
let SnThe received signal strength of the vehicle-mounted antenna with the number n; the signal intensity difference value when the multiple vehicle-mounted antennas are selected is Δ;
setting the received signal intensity sequence of the plurality of pairs of vehicle-mounted antennas after one-time signal detection as follows: s2>S1>S3；
When S is2-S1>Selecting the vehicle-mounted antenna S2As a working antenna;
when S is2-S1<∆、S2-S3>When it is, select the vehicle-mounted antenna S2And a vehicle-mounted antenna S1As a working antenna;
when S is2-S1<∆、S2-S3<When it is, select the vehicle-mounted antenna S 1Vehicle-mounted antenna S2And vehicle S3As an operating antenna.
Preferably, in the above technical scheme, the signal strength difference is set by the setting module.
Compared with the prior art, the invention has the following beneficial effects:
1. the vehicle-mounted antenna system for the rail transit vehicle-ground wireless system is characterized in that in the running process of a train, the vehicle-mounted antenna selected by the accurate measurement of the position of the train and the vehicle-mounted antenna with the optimal signal selected by the signal detection module are comprehensively or independently judged by combining a train positioning system, the vehicle-mounted antenna system is triggered to automatically adopt the preset optimal vehicle-mounted antenna or the vehicle-mounted antenna with the optimal signal for receiving and transmitting the wireless signal, and other unselected station antennas are bypassed by the vehicle-mounted combiner, namely are not connected to the vehicle-mounted access unit. The vehicle-mounted antenna system improves the strength of receiving useful signals, avoids losing transmitting power and receiving interference signals, reduces the loss power to the minimum, and improves the data transmission rate and the performance of the whole vehicle-ground wireless system.
2. The invention can select one or more vehicle-mounted antennas with the best signals for receiving and transmitting wireless signals according to the requirements, thereby not only reducing the power consumption, but also improving the strength of receiving useful signals.
Drawings
Fig. 1 is a structural diagram of a conventional on-vehicle combiner.
Fig. 2 is a configuration diagram of the arrangement of the vehicle-mounted antenna system according to the present invention.
Fig. 3 is a block diagram of a vehicle antenna system for a rail transit vehicle-to-ground wireless system according to the present invention.
Fig. 4 is a structural diagram of an in-vehicle combiner according to the present invention.
Description of the main reference numerals:
1-vehicle antenna, 2-leaky cable.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Fig. 3 shows a block diagram of a vehicle-mounted antenna system for a rail transit vehicle-to-ground wireless system according to a preferred embodiment of the present invention.
As shown in fig. 3, the vehicle-mounted antenna system for a rail transit vehicle-to-ground wireless system includes: the train-mounted antenna system comprises a vehicle-mounted antenna module 10, a signal detection module 20, a train positioning system 30, an antenna selection module 40, a setting module 80, a connection control module 60 and a vehicle-mounted combiner 50.
The vehicle-mounted antenna module 10 has a plurality of pairs of vehicle-mounted antennas disposed on the train, and the plurality of pairs of vehicle-mounted antennas are respectively connected to the vehicle-mounted combiner 50. Specifically, the number of the vehicle-mounted antennas can be two aiming at the positions of leaky cables of the trains which are all on the ground elevated section, and the two pairs of the vehicle-mounted antennas are respectively arranged on two sides of the trains; furthermore, aiming at the tracks combined by the underground tunnel and the ground elevated sections, the vehicle-mounted antennas are four pairs, the two pairs of vehicle-mounted antennas are respectively arranged on two sides of the train, and the two pairs of vehicle-mounted antennas are arranged on the top of the train. Each vehicle-mounted antenna can work independently to receive and transmit wireless signals. The antennas can also be connected through a vehicle-mounted combiner, and the received signals are superposed or the transmitting signal is branched to each vehicle-mounted antenna for transmitting.
The signal detection module 20 is connected with the vehicle-mounted antenna module 10 and is used for periodically acquiring the signal intensity of each vehicle-mounted antenna in the vehicle-mounted antenna module 10; specifically, during the operation of the system, each vehicle-mounted antenna keeps normal signal reception, and the strength of the useful signal received by each vehicle-mounted antenna is measured and recorded through the signal detection module 20. The measurement process is preferably performed periodically, and the period is configurable, such as once detection in 5-7 seconds; further, arithmetic average processing may also be performed on the measurement results of the plurality of measurements.
The train positioning system 30 is configured to obtain a corresponding geographic coordinate signal according to a preset geographic coordinate point of a geographic position of the train on the track when the train passes through the preset geographic coordinate point, and send the geographic coordinate signal to the antenna selection module; specifically, an antenna switching trigger point is set according to the geographical position characteristics along the train track, and when a train passes through the antenna switching trigger point of the train track, the train positioning system can automatically send the current geographical coordinate signal to the antenna selection module.
Because the train line can be kept unchanged for a long time after being built, for example, a tunnel entrance and a train return line are fixed and unchanged, the used vehicle-mounted antenna can be set according to the geographical position of the train line, for example, when a train runs on the ground, the right vehicle-mounted antenna close to a ground leaky cable is used for the best working performance, when the train enters the tunnel from the ground, the leaky cable is installed at the top of the tunnel, and at the moment, the vehicle-mounted antenna on the roof is used for the best working performance.
During the operation of the subway, the train positioning system 30 can obtain the geographical coordinate signal of the precise position of the track where the train is located. Thus, in the above method, the signal detection module 20 may be replaced with an input to the antenna selection module 40 based on the geographic coordinate signal provided by the train positioning system 30.
The setting module 80 is configured to configure one of a signal detection mode, a geographic coordinate detection mode and a comprehensive detection mode, and the setting module 80 is preferably in a manual setting mode, and can manually set an antenna receiving mode of a train on the track line according to the type of the railway.
The antenna selection module 40 is respectively connected with the setting module 80, the signal detection module 20 and the train positioning system 30, and is used for selecting the vehicle-mounted antenna with the strongest signal detected by the signal detection module 20 when the signal detection mode is configured; when a geographic coordinate detection mode is configured, acquiring a corresponding vehicle-mounted antenna according to a geographic coordinate signal; when the comprehensive detection mode is configured, the vehicle-mounted antenna with the strongest signal detected by the signal detection module 20 is compared with the vehicle-mounted antenna obtained according to the geographic coordinate signal, when the vehicle-mounted antenna with the strongest signal detected by the signal detection module 20 is consistent with the vehicle-mounted antenna obtained according to the geographic coordinate signal, the vehicle-mounted antenna corresponding to the geographic coordinate signal is selected when the vehicle-mounted antenna with the strongest signal detected by the signal detection module 20 is inconsistent with the vehicle-mounted antenna obtained according to the geographic coordinate signal.
Wherein the antenna selection module 40 performs the selection process based on the following logic:
1. selecting a pair of vehicle-mounted antennas with strongest received signals;
2. if the useful signals of the plurality of vehicle-mounted antennas are corresponding, the plurality of vehicle-mounted antennas can be simultaneously selected; for example, in a parking lot, the base station signal is transmitted through the directional antenna, and the 3-plane vehicle-mounted antenna works simultaneously to achieve the best effect. Further, when the signal detection mode or the comprehensive detection mode is configured, the algorithm for judging the signal strength of the multiple onboard antennas received by the signal detection mode, namely comparing and selecting the signal strength of the multiple onboard antennas sent by the signal detection module by the antenna selection module, is as follows:
suppose SnReceived signal strength for antenna number n; the signal strength difference when the link is selected by multiple antennas is set in advance by the user in the setting module 80.
The signal strength sequence of 3 pairs of vehicle-mounted antennas after a certain signal detection is executed is as follows: s2>S1>S3；
When S is2-S1>Selecting the vehicle-mounted antenna S2As a working antenna;
when S is2-S1<∆、S2-S3>When a vehicle antenna S is selected2And a vehicle-mounted antenna S1As a working antenna;
when S is2-S1<∆、S2-S3<When a vehicle antenna S is selected2Vehicle-mounted antenna S1And a vehicle-mounted antenna S3As an operating antenna.
3. When the train is configured in the geographic coordinate detection mode, for example, when a train runs from the ground to a tunnel entrance, the train positioning system 30 senses an antenna switching trigger point of a preset geographic coordinate, the train positioning system 30 triggers a geographic coordinate signal (such as line coordinate information) to the antenna selection module 40, based on the information, the antenna selection module 40 learns that the train enters the underground vehicle-mounted antenna from the ground, and the vehicle-side antenna used originally does not match any more because the position of a leaky cable in the tunnel is high, so that the antenna selection module 40 selects the vehicle-mounted antenna corresponding to the geographic coordinate signal acquired by the train positioning system 30 as a working antenna, and triggers the connection control module 60 to select the vehicle-mounted antenna on the roof of the train to work.
4. When the integrated detection mode is configured, for example, when a train runs from the ground to a tunnel entrance, the train positioning system 30 senses a preset geographic coordinate trigger point, the train positioning system 30 triggers a geographic coordinate signal (e.g., line coordinate information) to the antenna selection module 40, based on the information, the antenna selection module 40 learns that the train will enter the underground vehicle-mounted antenna from the ground, and the vehicle-mounted antenna that is originally used is not matched any more because the position of a leaky cable in the tunnel is high, and at this time, if the signal detection module 20 fails to acquire the vehicle-mounted antenna with the strongest signal in time periodically, the vehicle-mounted antenna with the strongest signal detected by the signal detection module 20 is inconsistent with the vehicle-mounted antenna corresponding to the geographic coordinate signal acquired by the train positioning system 30, so that the antenna selection module 40 selects the vehicle-mounted antenna corresponding to the geographic coordinate signal acquired by the train positioning system 30 as the communication antenna, the trigger connection control module 60 selects the operation of the roof on-board antenna of the train. And then when the train stably runs in the tunnel, the train positioning system and the vehicle-mounted antenna detected by the signal detection module are consistent, and communication is carried out according to the vehicle-mounted antenna obtained by the signal detection module 20.
The connection control module 60 is respectively connected to the vehicle-mounted combiner 50 and the antenna selection module 40, and is configured to control the vehicle-mounted combiner 50 to switch to the selected vehicle-mounted antenna according to the vehicle-mounted antenna selected by the antenna selection module 40. The on-board combiner 50 may connect the currently selected working antenna and disconnect other antennas according to the disconnection information provided by the connection control module 60.
The vehicle-mounted access unit 70 (vehicle-mounted terminal) is connected to the vehicle-mounted combiner 50 to access the selected vehicle-mounted antenna. After the connection control is executed, the current optimal vehicle-mounted antenna system can be provided to transmit and receive signals for the vehicle-mounted access unit, and the whole vehicle-mounted antenna system is minimally damaged and achieves the optimal signal intensity. Because the antennas in the antenna system work independently, the on-off of each pair of vehicle-mounted antennas can be controlled, and a part of the vehicle-mounted antennas do not work during working, so that the signal loss can be reduced.
Next, an application implementation of the vehicle-mounted antenna system in the embodiment will be described in detail to make the concept of the present invention more apparent to those skilled in the art.
As shown in fig. 2, the selected subway line has underground sections and ground sections, which are limited by the deployment limitation of the leaky cable, the leaky cable 2 is deployed at the position of 3.8 meters on the top of the tunnel at the underground sections, and the leaky cable 2 can only be installed on the supports with the height of 1 meter on both sides of the track at the ground sections.
Because the train is large in size, if only the roof antenna is installed, the signal of the leaky cable on the ground section can be shielded by the train body, and the receiving effect of the roof antenna is greatly influenced. Therefore, the antenna must be mounted on the vehicle side. The vehicle-mounted antenna module 10 is finally determined. The vehicle-mounted antenna 1 is composed of a roof vehicle-mounted antenna, a left side vehicle-mounted antenna, and a right side vehicle-mounted antenna.
The comprehensive detection mode is used as the detection mode of the antenna through the manual setting of the setting module, the train starts to run, the vehicle-mounted antenna system is powered on, the three-side vehicle-mounted antenna is connected to the signal detection module 20, the signal detection module 20 simultaneously measures useful signals received by the three-side vehicle-mounted antenna, and the signal intensity of the three-side vehicle-mounted antenna is respectively recorded.
The period for which signal measurements are made may be set based on the speed at which the train is moving, e.g. a measurement may be made in 5 seconds for a line designed to have a speed of 100km/h and in 6 seconds for a line designed to have a speed of 80 km/h. To avoid errors caused by single measurement inaccuracies, the signal detection module 20 may perform an arithmetic average process on the measurements of multiple measurements. The signal detection module 20 sends each vehicle antenna measurement to the antenna selection module 40.
Meanwhile, specific position points of the train track, where antenna switching is required, are measured in advance, for example, a position where the train enters an underground tunnel from the ground, a position where the train enters the ground from the underground tunnel, a position where the train turns back from a left line to a right line, a position where the train turns back from the right line to the left line, and the like, and are specifically shown in table 1. The location information is stored in the train positioning system 30, and once the train positioning system determines that the train is moving to the location point, the train positioning system sends an instruction to the antenna selection module 40 to perform antenna switching.
Table 1: the particular location and corresponding optimal antenna selection in this embodiment
| Line coordinate | Location description | Optimal antenna selection |
| DK00.100 | The left line is turned back to the right line | Right side vehicle antenna |
| DK10.234 | Ground entering underground tunnel | Top vehicle-mounted antenna |
| DK16.432 | Underground tunnel enters ground | Right side vehicle antenna |
| DK22.789 | The right line is folded back to the left line | Left side vehicle antenna |
In this embodiment, the train first runs on the ground, and the leaky cable is installed beside the right track in the running direction of the train. The signal detection module sets a measurement period of 5 seconds, and obtains the signal intensity of each sub-antenna after arithmetic averaging of 10 measurement results: roof antenna-100 dBm, right side-60 dBm, left side-105 dBm.
Because the train does not reach the next antenna switching specific geographical position point for a long time after passing through the antenna switching specific geographical position point DK00.100, the train positioning system 30 is consistent with the vehicle-mounted antenna selected by the signal detection module 20, and based on the signal strength of each vehicle-mounted antenna measured by the signal detection module 20 (roof vehicle-mounted antenna-100 dBm, right vehicle-mounted antenna-60 dBm, left vehicle-mounted antenna-105 dBm), the antenna selection module 40 selects the right vehicle-mounted antenna with the best signal as the working antenna according to the strength of the useful signal.
The antenna selection module 40 sends the selection result (the vehicle-mounted antenna on the right side of the vehicle) to the connection control module 60, and the connection control module 60 controls the connection relationship of the plurality of vehicle-mounted antennas in the vehicle-mounted combiner 50, so that only the selected vehicle-mounted antenna on the right side of the vehicle is connected with the vehicle-mounted access unit, and the vehicle-mounted antenna on the top side of the vehicle and the vehicle-mounted antenna on the left side of the vehicle are bypassed.
As shown in fig. 4, a plurality of on-off switches are disposed on the internal connection line of the vehicle-mounted combiner 50, in this embodiment, the antenna selection module 40 selects the right-side antenna as the working antenna, and at this time, the connection control module 60 controls the switch No. 1/2/3/4 in the vehicle-mounted combiner 50 to be turned off and the switch No. 5/6 to be turned on.
The train starts to enter the underground tunnel along with the running of the train, and the underground tunnel leaky cable is arranged beside the top of the tunnel. At this time, the signal detection module 20 measures the period according to the set 6 seconds, but if the measurement period of 6 seconds is not passed immediately when the train enters the tunnel, the detection of the antenna signal cannot be performed immediately, at this time, the train has already run to DK10.234, the train positioning system 30 determines that the train position is the same as the set trigger point, and then the position information (DK 10.234) is sent to the antenna selection module 40 in the vehicle-mounted antenna system, and at this time, the vehicle-mounted antenna with the strongest signal is inconsistent with the train positioning system 30 because the signal detection module 20 does not reach the next measurement period of 6 seconds, so the antenna selection module 40 selects the vehicle-mounted antenna selected by the train positioning system 30.
The antenna selection module 40 also stores the above table, and based on this location information (DK 10.234), knows that the train will enter the underground tunnel from the ground, and the best antenna at this time is the top car antenna. The antenna selection module 40 sends the selection result (top vehicle-mounted antenna) to the connection control module 60, and the connection control module 60 controls the connection relationship of the plurality of sub-antennas in the vehicle-mounted combiner 50, so that only the selected top vehicle-mounted antenna is connected with the vehicle-mounted access unit, and the left vehicle-mounted antenna and the right vehicle-mounted antenna which are not selected are bypassed.
When the signal detection module reaches the next 6-second measurement period, the signal intensity measurement of each vehicle-mounted antenna is executed, and the signal intensity of each vehicle-mounted antenna is obtained after the arithmetic average is carried out on the 10 measurement results: roof antenna-50 dBm, right side antenna-102 dBm, left side antenna-104 dBm.
Based on the signal intensity of each vehicle-mounted antenna measured by the signal detection module (roof vehicle-mounted antenna-50 dBm, right vehicle-mounted antenna-102 dBm, left vehicle-mounted antenna-104 dBm), the antenna selection module 40 selects the roof vehicle-mounted antenna with the best signal as the working antenna according to the intensity of the useful signal, and the working antenna is the same as the vehicle-mounted antenna selected by the vehicle-mounted control system, so that the antenna selection module 40 sends the selection result (roof vehicle-mounted antenna) to the connection control module 60, the connection control module 60 controls the connection relation of the plurality of vehicle-mounted antennas in the vehicle-mounted combiner 50, only the selected roof vehicle-mounted antenna is connected with the vehicle-mounted access unit, and the vehicle-right vehicle-mounted antenna and the vehicle-left vehicle-mounted antenna which are not selected are bypassed.
Similarly, when the train continues to run and runs to DK16.432, the train positioning system 30 determines that the train position is the same as the set trigger point, and sends the position information (DK 16.432) to the antenna selection module in the vehicle-mounted antenna system, and the antenna selection module knows that the train will enter the ground from the underground tunnel based on the position information (DK 16.432), and compares the position information with the strongest signal selected by the signal detection module 20, and uses the best antenna as the vehicle-mounted antenna on the right side of the train. The antenna selection module 40 sends the selection result (the vehicle-mounted antenna on the right side of the vehicle) to the connection control module 60, and the connection control module 60 controls the connection relationship of the plurality of vehicle-mounted antennas in the vehicle-mounted combiner 50, so that only the selected vehicle-mounted antenna on the right side of the vehicle is connected with the vehicle-mounted access unit, and the vehicle-mounted antenna on the right side of the vehicle and the vehicle-mounted antenna on the left side of the vehicle which are not selected are bypassed. When the train runs completely on the ground section, the train positioning system 30 is the same as the vehicle-mounted antenna selected by the signal detection module 20, so that the vehicle-mounted antenna can be selected according to the detection result of the signal detection module 20.
It should be noted that, when the signal detection mode is selected by the setting module 80, the train positioning system 30 does not operate, and completely operates in the signal detection mode 20, and the antenna selection module 40 selects the vehicle-mounted antenna with the strongest signal detected by the signal detection mode 20 as the communication antenna, and the method is consistent with the method of matching the signal detection mode 20 and the antenna selection module 40; when the setting module 80 selects the geographic coordinate detection mode, the signal detection mode 20 does not operate, and the train positioning system 30 completely operates, and the antenna selection module 40 acquires a corresponding vehicle-mounted antenna as a communication antenna from the geographic coordinate signal sent by the train positioning system 30, in a manner consistent with the manner of matching between the train positioning system 30 and the antenna selection module 40.
In conclusion, in the running process of the train, the train positioning system is combined to perform comprehensive judgment on the vehicle-mounted antenna selected by the train positioning system for accurate measurement of the position of the train and the vehicle-mounted antenna with the optimal signal selected by the signal detection module, and the vehicle-mounted antenna system is triggered to automatically adopt the preset optimal vehicle-mounted antenna for receiving and sending the wireless signal, so that the signal intensity of the vehicle-mounted antenna is improved, the loss of transmitting power of other vehicle-mounted antennas and the reception of interference signals are avoided, the loss of power is reduced to the minimum, and the data transmission rate and performance of the whole train-ground wireless system are improved.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (6)
1. A vehicle antenna system for a rail transit vehicle-to-ground wireless system, comprising:
the vehicle-mounted antenna module is provided with a plurality of pairs of vehicle-mounted antennas arranged on the train;
the signal detection module is connected with the vehicle-mounted antenna module and is used for periodically acquiring the received signal strength of each pair of vehicle-mounted antennas in the vehicle-mounted antenna module;
the train positioning system is used for acquiring a corresponding geographic coordinate signal and sending the geographic coordinate signal to the antenna selection module when a train passes through a preset geographic coordinate point according to the preset geographic coordinate point;
the device comprises a setting module, a signal detection module, a geographic coordinate detection module and a comprehensive detection module, wherein the setting module is used for configuring one of a signal detection mode, a geographic coordinate detection mode and a comprehensive detection mode;
the antenna selection module is respectively connected with the setting module, the signal detection module and the train positioning system, and selects the current specific vehicle-mounted antenna according to the detection mode configured by the setting module;
the vehicle-mounted combiner is respectively connected with the plurality of pairs of vehicle-mounted antennas and the vehicle-mounted access unit and is used for respectively controlling the on-off of the plurality of pairs of vehicle-mounted antennas; and
the connection control module is respectively connected with the antenna selection module and the vehicle-mounted combiner and is used for controlling the vehicle-mounted combiner to switch the selected vehicle-mounted antenna to be accessed into the vehicle-mounted access unit according to the vehicle-mounted antenna selected by the antenna selection module;
when the setting module is configured with a signal detection mode, the antenna selection module selects the vehicle-mounted antenna with the strongest signal detected by the signal detection module;
when the setting module is configured with a comprehensive detection mode, the antenna selection module compares the vehicle-mounted antenna with the strongest detection signal of the signal detection module with the vehicle-mounted antenna obtained according to the geographic coordinate signal, and selects the vehicle-mounted antenna with the strongest detection signal of the signal detection module when the vehicle-mounted antenna and the vehicle-mounted antenna are consistent, and selects the vehicle-mounted antenna corresponding to the geographic coordinate signal when the vehicle-mounted antenna and the vehicle-mounted antenna are inconsistent;
when a signal detection mode or a comprehensive detection mode is configured, the antenna selection module selects according to the received signal strength of the multiple vehicle-mounted antennas sent by the signal detection module, and the steps of:
let SnThe received signal strength of the vehicle-mounted antenna with the number n; delta is the signal intensity difference value when a plurality of pairs of vehicle-mounted antennas are selected;
setting the received signal intensity sequence of the plurality of pairs of vehicle-mounted antennas after one-time signal detection as follows: s2>S1>S3；
When S is2-S1>Δ, selecting the vehicle-mounted antenna S2As a working antenna;
when S is2-S1<Δ、S2-S3>Delta time, selecting the vehicle-mounted antenna S2And a vehicle-mounted antenna S1As a working antenna;
when S is2-S1<Δ、S2-S3<Delta time, selecting the vehicle-mounted antenna S1Vehicle-mounted antenna S2And vehicle S3As an operating antenna.
2. The vehicle antenna system for a rail transit vehicle-to-ground wireless system of claim 1, wherein the setting module is configured to set a periodic interval measured by the signal detection module.
3. The vehicle-mounted antenna system for a rail transit vehicle-to-ground wireless system as claimed in claim 1, wherein an antenna switching trigger point is set according to geographical location characteristics along a train track, and when a train passes through the antenna switching trigger point of the train track, the train positioning system transmits a corresponding geographical coordinate signal to the antenna selection module.
4. The vehicle-mounted antenna system for a rail transit vehicle-to-ground wireless system as claimed in claim 1, wherein when the setting module configures a geographic coordinate detection mode, the antenna selection module obtains the corresponding vehicle-mounted antenna according to the geographic coordinate signal.
5. The vehicle antenna system of claim 1, wherein the antenna selection module selects the pair of vehicle antennas with the strongest signal as the currently active antenna.
6. The vehicle antenna system of claim 1, wherein the signal strength difference Δ is set by the setting module.
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| CN2018103222882 | 2018-04-11 | ||
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| CN116437324A (en) * | 2019-08-05 | 2023-07-14 | 北京小米移动软件有限公司 | Antenna panel selection method, device and storage medium |
| CN111182500A (en) * | 2020-01-02 | 2020-05-19 | 中车株洲电力机车有限公司 | Communication method and system for rail transit |
| CN112389503B (en) * | 2020-11-26 | 2022-07-19 | 交控科技股份有限公司 | Communication system for tunnel rail transit and train control method |
| CN112389502B (en) * | 2020-11-26 | 2022-07-19 | 交控科技股份有限公司 | Communication system for ground rail transit and train control method |
| CN113949473B (en) * | 2021-11-22 | 2023-10-17 | 上海应用技术大学 | System and method for resisting co-channel interference in wireless communication of rail transit vehicle and ground |
| CN114513218A (en) * | 2022-02-15 | 2022-05-17 | 湖南中车时代通信信号有限公司 | Method and system for connecting 5G wireless terminal and train antenna |
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