CN113079549A - Cell switching method and device - Google Patents
Cell switching method and device Download PDFInfo
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- CN113079549A CN113079549A CN202010006313.3A CN202010006313A CN113079549A CN 113079549 A CN113079549 A CN 113079549A CN 202010006313 A CN202010006313 A CN 202010006313A CN 113079549 A CN113079549 A CN 113079549A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0055—Transmission or use of information for re-establishing the radio link
- H04W36/0058—Transmission of hand-off measurement information, e.g. measurement reports
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
- H04W36/0085—Hand-off measurements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
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Abstract
The embodiment of the invention provides a cell switching method and a device, wherein the method comprises the following steps: receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter; measuring according to the measurement control information and generating a measurement report; and reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report. According to the cell switching method and device provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a cell switching method and apparatus.
Background
In the traffic systems such as railways, tracks, high-speed magnetic levitation and the like, the train-ground wireless system bears key information such as train operation control, positioning data, voice scheduling and the like on the safe operation of the trains, and the information has high requirements on transmission reliability, time delay and the like.
In the prior art, a train-ground wireless communication system typically adopts a redundant structure, and a head train and a tail train work by adopting two sets of completely same vehicle-mounted terminal equipment so as to ensure the performance of the system
However, after the transmission delay of the LTE wireless communication system for rail transit is optimized, the transmission delay can reach about 5ms when there is no handover, the transmission delay of about 5ms can meet the system requirements, and the average transmission delay is 40-100ms when there is handover. The transmission delay of 40-100ms cannot meet the system requirements. Therefore, when the head car and the tail car do not carry out wireless cell switching, the time delay can meet the requirement; on the switching overlapping band between cells, only one terminal is switched, and in addition, the service time delay of the terminal without switching can also meet the requirement; however, when both terminals are in handover, the time delay cannot meet the requirement, especially for the 5ms time delay of high-speed magnetic levitation, so that the safety and reliability of the system are reduced.
Disclosure of Invention
The embodiment of the invention provides a cell switching method and a cell switching device, which are used for solving the technical problems in the prior art.
In order to solve the foregoing technical problem, in one aspect, an embodiment of the present invention provides a cell handover method, including:
receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter;
measuring according to the measurement control information and generating a measurement report;
and reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
Further, the performing measurement according to the measurement control information and generating a measurement report specifically includes:
acquiring an actual measurement result of an adjacent cell;
if the terminal is a tail car terminal, determining a delay measurement result of an adjacent cell according to the actual measurement result and the switching delay parameter;
and if the delay measurement result meets the switching event triggering condition, generating a measurement report.
Further, the delay measurement is equal to the actual measurement minus the handover delay parameter.
Further, the actual measurement result is included in the measurement report.
Further, before determining the delay measurement result of the neighboring cell, the method further includes:
and judging whether the terminal is a tail car terminal or not according to the number of the carriage where the terminal is positioned in the train formation, the train direction and the running direction of the train.
Further, the performing measurement according to the measurement control information and generating a measurement report specifically includes:
acquiring an actual measurement result of an adjacent cell;
if the terminal is a head-mounted terminal, judging whether the actual measurement result meets a switching event triggering condition;
and if the actual measurement result meets the switching event triggering condition, generating a measurement report.
In another aspect, an embodiment of the present invention provides a cell handover method, including:
measurement control information issued to a target terminal; the measurement control information comprises a switching delay parameter;
receiving a measurement report reported by the target terminal, wherein the measurement report is generated after the target terminal performs measurement according to the measurement control information;
and carrying out cell switching judgment according to the measurement report.
In another aspect, an embodiment of the present invention provides a terminal, including:
the receiving module is used for receiving the measurement control information issued by the source base station; the measurement control information comprises a switching delay parameter;
the measurement module is used for measuring according to the measurement control information and generating a measurement report;
and the reporting module is used for reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
In another aspect, an embodiment of the present invention provides a base station, including:
the issuing module is used for issuing the measurement control information to the target terminal; the measurement control information comprises a switching delay parameter;
a receiving module, configured to receive a measurement report reported by the target terminal, where the measurement report is generated by the target terminal performing measurement according to the measurement control information;
and the switching judgment module is used for judging cell switching according to the measurement report.
In another aspect, an embodiment of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the above method when executing the computer program.
According to the cell switching method and device provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Drawings
Fig. 1 is a schematic diagram of a cell handover method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a system according to an embodiment of the present invention;
fig. 3 is a schematic diagram of signaling interaction in a handover process according to an embodiment of the present invention;
fig. 4 is a logic flow diagram of terminal type determination provided in the embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a principle of determining a terminal type according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a cell handover method according to another embodiment of the present invention;
fig. 7 is a schematic diagram of a terminal according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a base station according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
In the traffic systems such as railways, tracks, high-speed magnetic levitation and the like, a train-ground wireless system transmits key information such as train operation control, positioning data and the like, wherein the information has high requirements on transmission reliability, time delay and the like.
The existing train-ground communication system adopts A, B dual-network design, and A, B dual-network are mutually physically independent and work in parallel. The network A is used for the transmission of safety data, and the network B is used for the transmission of comprehensive bearing service. And the train positioning data and the operation control data are transmitted in the network A and the network B simultaneously. The operation control cluster voice, train operation data, train diagnosis data, passenger information service and additional service information are only transmitted in the B network.
The control center is respectively provided with core network equipment of a network A and core network equipment of a network B. The access of each service system is realized through the central switch, and the isolation among different services and the network security requirements are realized simultaneously. The LTE vehicle-mounted terminal is respectively arranged at the head and the tail of the train and comprises a vehicle-mounted access unit, an antenna feeder system and the like. The train head and the train tail are respectively provided with a vehicle-mounted terminal, one vehicle-mounted terminal is connected to the A network to transmit train positioning data and operation control data, and the other vehicle-mounted terminal is connected to the B network to transmit train positioning data, operation control cluster voice, train operation data, train diagnosis data, passenger information service and additional service information.
When the train moves, the vehicle-mounted terminal of the network service is switched from one cell to another cell, and the system enables the terminal to select a proper working cell on the basis of considering the signal intensity or quality of the cell so as to ensure the performance of data transmission between a user and a network.
In the handover of the existing wireless system, there are several ways to determine whether the terminal needs cell handover:
1. depending on the received signal carrier level decision. When the signal carrier level is below a threshold level (e.g., -100 dBm), a handoff is performed. This approach is the main decision approach, and in 2G, 3G and 4G systems, various switching criteria are derived from the signal strength:
criterion 1: relative signal criteria. The base station with the strongest received signal is selected at any time. The disadvantages of this criterion are: too many unnecessary cell handovers can be initiated if the signal strength of the original base station still meets the requirements.
Criterion 2: with a threshold specified relative signal strength criterion. The mobile subscriber is only allowed to perform a handover if the signal of the current base station is weak enough (below a certain threshold) and the signal of the target base station is stronger than the signal of the source base station.
Criterion 3: a relative signal strength criterion with a hysteresis margin. The terminal is only allowed to perform a handover in case the signal strength of the target base station is much stronger than the signal strength of the original base station (i.e., greater than the hysteresis margin). This technique can prevent the mobile station from repeatedly switching back and forth between two base stations due to signal fluctuations, i.e., the "ping-pong effect".
Criterion 4: with hysteresis margin and threshold specified relative signal strength criteria. The terminal is only allowed to perform a handover when the signal level of the current base station is below a prescribed threshold and the signal strength of the target base station is above the current base station by a given hysteresis margin.
2. Based on the signal-to-noise ratio of the received signal. And when the signal-to-noise ratio is lower than a given value, switching.
3. The handover is performed using the location information of the terminal and the base station. Including obtaining location externally, predicting location based on motion status, obtaining distance via maps, etc., and then making handover decisions in conjunction with both signal strength and location.
4. And in the switching process, the factors such as cell load, service capacity, service type and the like are considered to carry out decision switching.
In the switching scheme in the prior art, only the switching control of a single terminal is aimed at, and an LTE wireless communication system for rail transit and a train-ground wireless system bear key information of safe operation such as train operation control and positioning, and the information has high requirements on the reliability, time delay and the like of transmitted data, for example, the time delay of positioning data required by high-speed magnetic levitation is less than 5ms, and the time delay of voice scheduling is less than 50 ms. The transmission delay of the LTE system is 40-100ms when switching is performed, and can be optimized to be within 5ms when switching is not performed.
Therefore, the train is respectively provided with a vehicle-mounted terminal on the head train and the tail train, and when the train-ground wireless system works and the head train terminal and the tail train terminal do not carry out wireless cell switching, the time delay can meet the requirement; on the switching overlapping band between cells, only one terminal is switched, and the service delay can also meet the requirement under the condition that the other terminal is not switched; however, when both terminals are switched, the delay cannot meet the requirement, especially for the 5ms delay of high-speed magnetic levitation.
In order to solve the above technical problems in the prior art, fig. 1 is a schematic diagram of a cell handover method according to an embodiment of the present invention, and as shown in fig. 1, an embodiment of the present invention provides a cell handover method, an execution subject of which is a vehicle-mounted terminal. The method comprises the following steps:
step S101, receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter.
Specifically, the source base station first sends measurement control information to the terminal, where the measurement control information includes a measurement target, a measurement quantity, a measurement reporting criterion, and the like.
For example, the measurement control information in the LTE system includes a measConfig cell in the rrcconnectionreconfiguration message, and includes an object to be measured by the UE, a cell list, a reporting mode, a measurement identifier, an event parameter, and the like.
In the embodiment of the present invention, the measurement control information sent by the base station to the terminal further includes a handover delay parameter Qdelay, where the Qdelay is used to delay the handover of the terminal.
And the terminal receives measurement control information which is issued by the source base station and contains the switching delay parameter.
And step S102, measuring according to the measurement control information and generating a measurement report.
Specifically, after receiving measurement control information issued by a source base station, a terminal performs measurement according to the measurement control information, and generates a measurement report when a measurement result meets a measurement report condition.
For example, in the LTE system, the terminal needs to measure the neighboring cells in the cell list according to the cell list in the measurement control information, then judge whether the measurement result meets the event trigger condition according to the event parameter and the handover delay parameter in the measurement control information, and generate a measurement report when the event trigger condition is met.
And step S103, reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
Specifically, after generating the measurement report, the terminal reports the measurement report to the source base station. And the source base station receives the measurement report reported by the terminal.
And after receiving the measurement report reported by the terminal, the source base station carries out cell switching judgment according to the measurement report.
And if the network side allows the switching, the source base station sends a switching request message to the target base station to which the target cell belongs. The source base station may directly send the handover request message to the target base station, or may forward the handover request message through a wireless network device, such as an SGSN of a 3G network, an MSC, an MME in a 4G network, or the like.
And after receiving the switching request message, the target base station sends a switching request response message to the source base station, wherein the switching request response message carries information such as switching resource allocation and the like.
And after receiving the switching request response message, the source base station sends a switching command to the terminal to instruct the terminal to switch to the target cell.
And the terminal establishes a link with the target cell according to the instruction of the switching command and sends a switching completion message to the target cell.
After the terminal accesses the target cell, the target base station sends a resource release request to the source base station, and the source base station releases the resource allocated to the terminal after receiving the resource release request.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Based on any one of the above embodiments, further, the performing measurement according to the measurement control information and generating a measurement report specifically includes:
acquiring an actual measurement result of an adjacent cell;
if the terminal is a tail car terminal, determining a delay measurement result of an adjacent cell according to the actual measurement result and the switching delay parameter;
and if the delay measurement result meets the switching event triggering condition, generating a measurement report.
Specifically, in the embodiment of the present invention, the specific steps of performing measurement according to the measurement control information and generating the measurement report are as follows:
first, the terminal measures the neighboring cells and obtains actual measurement results of the neighboring cells.
And then, the terminal reports the measurement report according to the type of the terminal.
In a normal traffic system, the operation control system transmits information that the terminal car 1 is in the direction of kilometer scale increase/decrease and the train running direction is mileage increase/decrease to the vehicle-mounted terminal of the train-ground wireless system.
In the embodiment of the invention, the vehicle-mounted wireless terminals are divided into a head vehicle terminal and a tail vehicle terminal.
A head-up terminal: if the vehicle-mounted terminal is positioned in the direction that the terminal car 1 and the terminal car 1 increase in kilometers, and the train running direction is the direction that the mileage increases; or the terminal is positioned in the direction that the number of the end cars n and 1 is smaller in kilometer scale, and the running direction of the train is the direction that the mileage is reduced.
A tail car terminal:
if the terminal is located at the end car 1, the terminal is a tail car terminal if one of the following conditions is met:
a. the end car 1 is in the direction of increasing kilometers and the train running direction is in the direction of decreasing mileage,
b. the end car 1 is in the direction of decreasing kilometer posts and the train running direction is the direction of increasing mileage.
If the terminal is located at the end car n and one of the following conditions is met, the terminal is a tail car terminal:
a. the direction of the end car 1 is the direction of the increase of the kilometer post and the running direction of the train is the direction of the increase of the mileage
b. The end car 1 is in the direction of decreasing kilometer posts and the train running direction is the direction of decreasing mileage.
The vehicle-mounted terminal determines whether the terminal is a head car terminal or a tail car terminal according to the position of the end car 1, the running direction of the train, the information of the position of the end car 1or the information of the position of the end car, the position of the end car.
And if the terminal is the tail vehicle terminal, the terminal determines the delay measurement result of the adjacent cell according to the actual measurement result and the switching delay parameter.
And finally, judging whether the delay measurement result of the adjacent cell meets the switching event triggering condition, and generating a measurement report when the delay measurement result meets the switching event triggering condition.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Based on any one of the above embodiments, further, the performing measurement according to the measurement control information and generating a measurement report specifically includes:
acquiring an actual measurement result of an adjacent cell;
if the terminal is a head-mounted terminal, judging whether the actual measurement result meets a switching event triggering condition;
and if the actual measurement result meets the switching event triggering condition, generating a measurement report.
Specifically, in the embodiment of the present invention, the specific steps of performing measurement according to the measurement control information and generating the measurement report are as follows:
first, the terminal measures the neighboring cells and obtains actual measurement results of the neighboring cells.
And then, the terminal reports the measurement report according to the type of the terminal.
If the terminal is a head-to-vehicle terminal, the terminal directly judges whether the actual measurement result of the adjacent cell meets the trigger condition of the switching event.
And finally, when the actual measurement result meets the switching event triggering condition, generating a measurement report.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Based on any of the above embodiments, further, the delay measurement result is equal to the actual measurement result minus the handover delay parameter.
Specifically, in the embodiment of the present invention, the delay measurement result of the neighboring cell is equal to the actual measurement result minus the handover delay parameter.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Based on any of the above embodiments, further, the actual measurement result is included in the measurement report.
Specifically, in the embodiment of the present invention, the measurement report includes the actual measurement result of the target cell.
In other words, the handover method provided in the embodiment of the present invention does not change the decision of the base station for cell handover.
When the terminal is a head-up terminal, the triggering of the switching event is completed according to the actual measurement result of the target cell, the measurement report comprises the actual measurement result of the target cell, and the source base station performs switching judgment according to the actual measurement result of the target cell.
When the terminal is a tail-end terminal, the triggering of the switching event is completed according to the delay measurement result of the target cell, the measurement report comprises the actual measurement result of the target cell, and the source base station carries out switching judgment according to the actual measurement result of the target cell. The switching event is triggered by adopting the delay measurement result, so that the switching is delayed, the source base station still carries out switching judgment according to the actual measurement result of the target cell, the switching is delayed, the switching judgment of the source base station is not influenced, the simultaneous switching of two terminals on a train is avoided, and the compatibility of the system is improved.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Based on any of the foregoing embodiments, further before determining the delay measurement result of the neighboring cell, the method further includes:
and judging whether the terminal is a tail car terminal or not according to the number of the carriage where the terminal is positioned in the train formation, the train direction and the running direction of the train.
Specifically, in the embodiment of the present invention, before generating the measurement report, the terminal further needs to determine whether the terminal is a tail car terminal according to the number of the car in which the terminal is located in the train formation, the train direction, and the running direction of the train.
After the vehicle-mounted terminal is loaded into the train, the information that the position Pself in the train is at the end train 1or the last end train can be obtained. Pself ═ 1 indicates at the end car 1, and Pself ═ 0 indicates at the end car.
The operation control unit periodically sends the position information of the vehicle to the vehicle-mounted terminal. These include the direction of travel RunDir and the train heading PosDir.
RunDir ═ 1, which indicates that the train running direction is the increasing direction of the kilometer sign of the line; RunDir ═ 0, indicates that the train running direction is the line kilometer sign reduction direction.
PosDir ═ 1, which indicates that the end car 1 is increasing in the direction of the road kilometer post as viewed from the center of the vehicle; and PosDir is 0, and the end car 1 decreases in the direction of the line kilometer scale.
In the case of Pself ═ 0, hdelay ═ 1 is set if RunDir ═ 1 and PosDir ═ 1, or RunDir ═ 0 and PosDir ═ 0, and hdelay ═ 0 otherwise. The terminal is denoted as a tail terminal by hdelay ═ 1, and the terminal is denoted as a head terminal by hdelay ═ 0.
In the case of Pself ═ 1, hdelay ═ 1 is set if RunDir ═ 1 and PosDir ═ 0, or RunDir ═ 0 and PosDir ═ 1, and hdelay ═ 0 otherwise.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
The method in the above embodiment is described below by a specific example:
fig. 2 is a schematic structural diagram of a system according to an embodiment of the present invention, and as shown in fig. 2, the system includes an operation control unit, a vehicle-mounted terminal, a base station, and a core network. The vehicle-mounted terminal comprises an operation control interface unit, a wireless signaling transceiving unit, a measuring unit, a switching judging unit, a switching executing unit and the like.
1. And an operation control unit. The operation and control unit provides the information of the position of the end car 1 and the running direction of the train for the vehicle-mounted terminal.
2. And the vehicle-mounted terminal operation control interface unit. The vehicle-mounted terminal determines whether the terminal is a head car terminal or a tail car terminal according to the position of the end car 1, the running direction of the train, the information of the position of the end car 1or the information of the position of the end car, the position of the end car.
3. And the vehicle-mounted terminal wireless signaling transceiving unit. And the base station is responsible for receiving and transmitting wireless signaling between the terminal base stations. The unit sends the parameters (such as measurement carrier, measurement object, etc.) of the measurement control information to the measurement unit and the switching decision unit, and interacts with the switching execution unit to complete the receiving and sending of the switching related signaling.
4. And a vehicle-mounted terminal measuring unit. And according to the measurement parameters received from the wireless signaling transceiving unit, performing measurement and sending the measurement result to the switching judgment unit in a periodic mode or an event mode.
5. A handover determination unit. And the switching judgment unit adjusts the adjacent cell measurement value reported by the measurement unit according to the terminal attribute and then uses the adjusted measurement value. And then decides the algorithm and the decision parameter according to the event in the measurement control message. To determine whether to send a measurement report and trigger a handover.
6. And the vehicle-mounted terminal switching execution unit. And the terminal switching execution unit is matched with the network to complete the switching of the cell.
Fig. 3 is a schematic diagram of signaling interaction in a handover process according to an embodiment of the present invention, and as shown in fig. 3, a system has the following working flow:
1. and the vehicle-mounted terminal determines whether the attribute of the vehicle-mounted terminal is a head vehicle terminal or a tail vehicle terminal according to the information of the operation control unit, and sets a switching delay attribute.
Fig. 4 is a logic flow chart of terminal type determination provided in the embodiment of the present invention, and as shown in fig. 4, after the vehicle-mounted terminal is loaded into a train, information about whether the position Pself in the train is at the end car 1or the last end car is obtained. Pself ═ 1 indicates at the end car 1, and Pself ═ 0 indicates at the end car.
The operation control unit periodically sends the position information of the vehicle to the vehicle-mounted terminal. These information include the direction of travel (RunDir) and the train orientation (PosDir).
RunDir ═ 1, which indicates that the train running direction is the increasing direction of the kilometer sign of the line; RunDir ═ 0, indicates that the train running direction is the line kilometer sign reduction direction.
PosDir ═ 1, which indicates that the end car 1 is increasing in the direction of the road kilometer post as viewed from the center of the vehicle; and PosDir is 0, and the end car 1 decreases in the direction of the line kilometer scale.
Fig. 5 is a schematic diagram illustrating a principle of determining a terminal type according to an embodiment of the present invention, where, as shown in fig. 5, when Pself is equal to 0, if RunDir is 1 and PosDir is 1 (scene (a) in fig. 5), or RunDir is 0 and PosDir is 0 (scene (b) in fig. 5), hdelay is set to 1, otherwise hdelay is 0.
In the case of Pself 1, if RunDir 1 while PosDir 0 (scene (c) in fig. 5) or RunDir 0 while PosDir 1 (scene (d) in fig. 5), hdelay 1 is set, otherwise hdelay 0.
2. The base station sends a measurement control message to the vehicle-mounted terminal, wherein the message comprises a measured object, a measured quantity, a measurement reporting criterion and the like, and also comprises a Qdelay parameter. The specific contents of different system messages are different, and the invention takes an LTE system as an example, but the invention is not influenced to be applied to other wireless systems.
The measurement message of LTE includes the measConfig cell in the rrcconnectionreconfiguration message, includes the object to be measured by the UE, the cell list, the reporting mode, the measurement identifier, the event parameter, and the like, and also includes the Qdelay parameter in the present invention.
3. Distribution of measurement control message parameters
The signaling transceiving unit of the vehicle-mounted terminal sends information such as a measured object, a cell list, a measurement identifier and the like to the measuring unit, and sends data such as the measured object, the cell list, a reporting mode, the measurement identifier, an event parameter and the like to the switching judging unit.
4. The measurement unit updates the list of measurements based on the received measurement configuration, and starts measurement-related operations on the measurement object using the new measurement list and the measurement start conditions. The measurement unit sends the measured value Qmeas of the serving cell filtered by the layer 3 and the measured values Qnmeas, i of all the adjacent cells (i is 1 … n, n is the number of the adjacent cells) to the handover decision unit.
5. The handover decision unit receives the measurement units Qmeas and Qnmeas, i.
If hdelay is 1, adjusting all the measurement results which are not the current service cell, Qnadj.i is Qnmeas, i-Qdelay;
if hdelay is 0, qnadj.i is not adjusted.
Qsmeas is used as the measured value of the current service cell, Qnadj, i is used as the measured value of the ith adjacent cell, and the parameter used for event judgment is from the configuration message sent by the network and sent to the switching judgment unit through the terminal signaling receiving and sending unit.
Taking LTE as an example, the determination unit takes Qnadj, i as the actual measurement value Mn and Qsmeas as Ms, and performs the determination of the subsequent handover. The criteria for the determination include, but are not limited to, the following:
eventA 3: the quality of the neighbor cell is above a threshold than the serving cell.
Event entry conditions: Mn-Offset-Hys > Ms; event leaving conditions: Mn-Offset + Hys < Ms.
Wherein: offset is a3-Offset + Ofs + Ocs-off-Ocn.
Mn: measurement results of neighbor cells.
Ofn: the neighbor frequency specific offset (i.e., offsetFreq is defined in measObjectEUTRA as the frequency corresponding to the neighbor)
And Ocn: the cell specific offset for that neighbor (i.e., celllndivudulanoffset is defined in measObjectEUTRA as the frequency corresponding to the neighbor) is set to zero if not configured for the neighbor.
Ms: the measurement results for the serving cell under no bias are calculated.
Ofs: is a frequency specific offset on the serving frequency (i.e. offsetFreq is defined in measObjectEUTRA as corresponding to the serving frequency).
And Ocs: the cell specific offset for the serving cell (i.e. celllndividualoffset is defined in measObjectEUTRA as corresponding to the serving frequency) is set to 0 if not configured for the serving cell.
Hys: is the hysteresis parameter for the event (i.e., hysteres is the parameter defined for the event in reportConfigEUTRA).
3-Offset: is the Offset parameter for the event (i.e., a3-Offset is the parameter defined for the event within reportConfigEUTRA).
Ofn, Ocn, Ofs, Ocs, Hys, and Off are in dB.
eventA 4: the quality of the neighbor cell is above an absolute threshold.
Event entry conditions: mn + Offset-Hys > Thresh; event leaving conditions: mn + Offset + Hys < Thresh.
Wherein Offset is Ofn + Ocn.
eventA 5: the serving cell quality is below an absolute threshold of 1 and the neighbor cell quality is above an absolute threshold of 2.
Event entry conditions: ms + Hys < Thresh1& Mn + Offset-Hys > Threah 2.
Event leaving conditions: Ms-Hys > Thresh1orMn + Offset + Hys < Thresh2 where Offset is off + Ocn.
If the measurement report condition is met, the switching judgment unit sends measurement report information to the switching execution unit, and the measurement result information in the message is the measured value of the adjacent cell output by the measurement unit, but not the measured value of the adjacent cell after adjustment.
6. And executing the switching. The terminal switching execution unit sends a measurement report message to the base station to request switching. And if the network allows, performing the switching process between the terminal and the base station.
6.1 the source cell switching execution unit sends the switching request message to the target cell. The source cell handover performing unit sends the handover request message to the target cell, which may be directly performed, or may be forwarded through a wireless network device, such as an SGSN of a 3G network, an MSC, an MME of a 4G network, and the like.
6.2 the target cell sends a switching request response message to the switching execution unit of the source cell, and the switching request response message carries information such as switching resource allocation.
6.3 the target cell sends a switching request message to the switching optimization unit, carrying the identification and signal intensity of the source cell and the identification and signal intensity of the target cell.
6.4 the source cell switching execution unit sends a switching command to instruct the terminal to switch to the target cell.
6.5 the terminal establishes a link with the target cell according to the instruction of the switching command and sends a switching completion message to the target cell.
6.6 the target cell sends message to the switch optimization unit, and sends the switch success message carrying the switch source cell identification and the target cell identification.
In the cell switching method in the above example, the base station is used to issue the parameter of switching delay to control the two terminals of the head car and the tail car on the train to switch at different times, so as to ensure that at least one path of service data transmission can meet the requirement of transmission delay.
Based on any of the above embodiments, fig. 6 is a schematic diagram of a cell handover method according to another embodiment of the present invention, and as shown in fig. 6, an embodiment of the present invention provides a cell handover method, an execution subject of which is a base station, the method including:
step S601, measurement control information is issued to a target terminal; the measurement control information comprises a switching delay parameter.
Step S602, receiving a measurement report reported by the target terminal, where the measurement report is generated after the target terminal performs measurement according to the measurement control information.
And step S603, carrying out cell switching judgment according to the measurement report.
Specifically, the source base station first sends measurement control information to the terminal, where the measurement control information includes a measurement target, a measurement quantity, a measurement reporting criterion, and the like.
For example, the measurement control information in the LTE system includes a measConfig cell in the rrcconnectionreconfiguration message, and includes an object to be measured by the UE, a cell list, a reporting mode, a measurement identifier, an event parameter, and the like.
In the embodiment of the invention, the measurement control information sent by the base station to the terminal also comprises a switching delay parameter Qdelay. Qdelay is used to delay the handover of the terminal.
And the terminal receives measurement control information which is issued by the source base station and contains the switching delay parameter.
And after receiving the measurement control information issued by the source base station, the terminal carries out measurement according to the measurement control information, and generates a measurement report when the measurement result meets the measurement report condition.
For example, in the LTE system, the terminal needs to measure the neighboring cells in the cell list according to the cell list in the measurement control information, then judge whether the measurement result meets the event trigger condition according to the event parameter and the handover delay parameter in the measurement control information, and generate a measurement report when the event trigger condition is met.
And after the terminal generates the measurement report, reporting the measurement report to the source base station. And the source base station receives the measurement report reported by the terminal.
And after receiving the measurement report reported by the terminal, the source base station carries out cell switching judgment according to the measurement report.
And if the network allows the switching, the source base station sends a switching request message to the target base station to which the target cell belongs. The source base station may directly send the handover request message to the target base station, or may forward the handover request message through a wireless network device, such as an SGSN of a 3G network, an MSC, an MME in a 4G network, or the like.
And after receiving the switching request message, the target base station sends a switching request response message to the source base station, wherein the switching request response message carries information such as switching resource allocation and the like.
And after receiving the switching request response message, the source base station sends a switching command to the terminal to instruct the terminal to switch to the target cell.
And the terminal establishes a link with the target cell according to the instruction of the switching command and sends a switching completion message to the target cell.
After the terminal accesses the target cell, the target base station sends a resource release request to the source base station, and the source base station releases the resource allocated to the terminal after receiving the resource release request.
According to the cell switching method provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
It should be noted that: the LTE system in each of the above embodiments is described as an example, but the cell handover method in the above embodiments is not limited to the LTE system, and may be applied to other wireless mobile communication systems, such as GSM, CDMA, and WCDMA.
Based on any of the above embodiments, fig. 7 is a schematic diagram of a terminal provided in an embodiment of the present invention, and as shown in fig. 7, an embodiment of the present invention provides a terminal, which includes a receiving module 701, a measuring module 702, and a reporting module 703, where:
the receiving module 701 is configured to receive measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter; the measurement module 702 is configured to perform measurement according to the measurement control information and generate a measurement report; the reporting module 703 is configured to report the measurement report to a source base station, so that the source base station performs cell handover decision according to the measurement report.
According to the terminal provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Based on any of the above embodiments, fig. 8 is a schematic diagram of a base station provided in an embodiment of the present invention, and as shown in fig. 8, an embodiment of the present invention provides a base station, which includes an issuing module 801, a receiving module 802, and a handover decision module 803, where:
the issuing module 801 is used for issuing measurement control information to a target terminal; the measurement control information comprises a switching delay parameter; the receiving module 802 is configured to receive a measurement report reported by the target terminal, where the measurement report is generated by the target terminal performing measurement according to the measurement control information; the handover decision module 803 is configured to perform a cell handover decision according to the measurement report.
According to the base station provided by the embodiment of the invention, the switching delay parameter is contained in the measurement control information, the head train terminal is normally switched, and the tail train terminal performs switching delay processing according to the switching delay parameter, so that two vehicle-mounted terminals on a unified train are prevented from being switched simultaneously, and the safety and reliability of train data transmission are improved.
Fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 9, the electronic device includes: a processor (processor)901, a communication Interface (Communications Interface)902, a memory (memory)903 and a communication bus 904, wherein the processor 901, the communication Interface 902 and the memory 903 are communicated with each other through the communication bus 904. The processor 901 and the memory 902 communicate with each other via a bus 903. The processor 901 may call logic instructions in the memory 903 to perform the following method:
receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter; measuring according to the measurement control information and generating a measurement report; and reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
Or the following method:
measurement control information issued to a target terminal; the measurement control information comprises a switching delay parameter; receiving a measurement report reported by the target terminal, wherein the measurement report is generated after the target terminal performs measurement according to the measurement control information; and carrying out cell switching judgment according to the measurement report.
In addition, the logic instructions in the memory may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Further, embodiments of the present invention provide a computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the steps of the above-described method embodiments, for example, including:
receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter; measuring according to the measurement control information and generating a measurement report; and reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
Or the following method:
measurement control information issued to a target terminal; the measurement control information comprises a switching delay parameter; receiving a measurement report reported by the target terminal, wherein the measurement report is generated after the target terminal performs measurement according to the measurement control information; and carrying out cell switching judgment according to the measurement report.
Further, an embodiment of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the computer program implements the steps in the above method embodiments, for example, including:
receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter; measuring according to the measurement control information and generating a measurement report; and reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
Or the following method:
measurement control information issued to a target terminal; the measurement control information comprises a switching delay parameter; receiving a measurement report reported by the target terminal, wherein the measurement report is generated after the target terminal performs measurement according to the measurement control information; and carrying out cell switching judgment according to the measurement report.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A method of cell handover, comprising:
receiving measurement control information issued by a source base station; the measurement control information comprises a switching delay parameter;
measuring according to the measurement control information and generating a measurement report;
and reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
2. The cell switching method according to claim 1, wherein the performing measurement according to the measurement control information and generating a measurement report specifically includes:
acquiring an actual measurement result of an adjacent cell;
if the terminal is a tail car terminal, determining a delay measurement result of an adjacent cell according to the actual measurement result and the switching delay parameter;
and if the delay measurement result meets the switching event triggering condition, generating a measurement report.
3. The cell switching method of claim 2, wherein the delay measurement result is equal to the actual measurement result minus the handover delay parameter.
4. The cell switching method according to claim 2, wherein the measurement report includes the actual measurement result.
5. The cell switching method according to claim 2, wherein before determining the delay measurement result of the neighboring cell, further comprising:
and judging whether the terminal is a tail car terminal or not according to the number of the carriage where the terminal is positioned in the train formation, the train direction and the running direction of the train.
6. The cell switching method according to claim 1, wherein the performing measurement according to the measurement control information and generating a measurement report specifically includes:
acquiring an actual measurement result of an adjacent cell;
if the terminal is a head-mounted terminal, judging whether the actual measurement result meets a switching event triggering condition;
and if the actual measurement result meets the switching event triggering condition, generating a measurement report.
7. A method of cell handover, comprising:
measurement control information issued to a target terminal; the measurement control information comprises a switching delay parameter;
receiving a measurement report reported by the target terminal, wherein the measurement report is generated after the target terminal performs measurement according to the measurement control information;
and carrying out cell switching judgment according to the measurement report.
8. A terminal, comprising:
the receiving module is used for receiving the measurement control information issued by the source base station; the measurement control information comprises a switching delay parameter;
the measurement module is used for measuring according to the measurement control information and generating a measurement report;
and the reporting module is used for reporting the measurement report to a source base station so that the source base station can carry out cell switching judgment according to the measurement report.
9. A base station, comprising:
the issuing module is used for issuing the measurement control information to the target terminal; the measurement control information comprises a switching delay parameter;
a receiving module, configured to receive a measurement report reported by the target terminal, where the measurement report is generated by the target terminal performing measurement according to the measurement control information;
and the switching judgment module is used for judging cell switching according to the measurement report.
10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor when executing the computer program performs the steps of the cell handover method according to any of claims 1 to 7.
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