WO2019042025A1

WO2019042025A1 - Anti-interference method and apparatus for wireless communication system of rail transit

Info

Publication number: WO2019042025A1
Application number: PCT/CN2018/095588
Authority: WO
Inventors: 印翀; 余刚
Original assignee: 武汉虹信通信技术有限责任公司
Priority date: 2017-08-30
Filing date: 2018-07-13
Publication date: 2019-03-07
Also published as: CN107396403A

Abstract

Provided are an anti-interference method and apparatus for a wireless communication system of rail transit. According to the characteristics that a moving trajectory of an on-board terminal of a train is fixed, and the mobility has a fixed rule, frequency bands of edge users in adjacent cells are dynamically staggered by means of monitoring the number of users residing in an adjacent cell or the frequency bands of the edge users in the adjacent cells are regularly staggered according to a moving rule of the train. Dynamically staggering the frequency bands of the edge users in the adjacent cells by means of monitoring the number of users residing in the adjacent cell comprises: a base station monitoring the number of users residing in a current cell and the number, fed back by the adjacent cell, of users residing in the adjacent cell, and carrying out periodical update, and if the number of users residing in the current cell is greater than 0 and the number of users residing in the adjacent cell is greater than 0, starting joint scheduling or ICIC with the adjacent cell to stagger the frequency bands of the users of both sides. The present invention is simple to implement, is efficient and accurate, does not need extra hardware investment, has an important market value, and is of great significance in making related industries in China take the leading position internationally.

Description

Anti-interference method and device for rail transit wireless communication system

Technical field

The present invention relates to the field of wireless communication technologies, and more particularly, to a technical solution for anti-interference of a wireless communication system in an LTE rail transit scenario.

Background technique

As an important means and effective measure to solve the traffic problems in big cities, urban rail transit system has the advantages of large volume, fast speed, safety, punctuality and comfort, and can drive the comprehensive development and utilization of urban land resources, which is of great significance to the long-term development of the city. . At the same time, with the rapid development of information and communication technology to broadband, the demand for rail transit information construction has also been continuously improved. The rail transit vehicle wireless communication system is mainly used as a key system for rail transit informationization to establish a two-way, stable, reliable and high-speed wireless data transmission channel between the train and the ground, and to provide a basic bearer network for other services of rail transit. The system is mainly composed of two parts: base station and vehicle subsystem. Referring to Figure 1, the on-board equipment of the subway train itself can receive and transmit data through the vehicle-mounted UE.

At present, the wireless communication system for rail transit vehicles has adopted LTE as the air interface transmission technology. The use of LTE for communication in the rail transit field is a relatively new wireless communication scheme. LTE can provide high-speed broadband connection, single base station. Coverage can be up to 48km. LTE adopts a cellular mobile communication system, and the communication network is composed of a plurality of base stations. There is a problem of co-channel interference between users at the edge of the adjacent base station, which is also a very common problem in the LTE communication system.

In the rail transit scene, when the train travels in a single direction independent track, such as a subway tunnel, the two rails coming and going are in different tunnels. In this case, there will be a big difference between the two trains in a single direction. Segment distance, so there is no interference problem with the communication terminal between the two cars. However, there are still many scenes, such as the outdoor elevated track section, where the two rails coming and going are in the same space, so that there will be two trains traveling in the same direction and meeting each other. When the two trains are in the adjacent community and are close to each other, Because the two trains belong to the same network and the frequency bands used are coincident, the problem of co-channel interference between the two vehicles will become more serious, which will seriously affect the quality of communication. Referring to FIG. 2, the vehicle A is set on the train A, and the vehicle B is set on the train B. The base station A and the base station B respectively provide services. When the two vehicles are at the edge of the adjacent base station, the distance is very close and belongs to different cells, which may cause Co-channel interference.

Technically, as long as the two vehicles use different frequency bands, this problem can be solved. ICIC technology is usually used to solve the problem of cell edge user interference, that is, at the edge of the neighboring cell, the UEs in the two cells cannot use all the frequency bands but only Some bands that are different from each other can be used. If the ICIC function is enabled, the interference problem of the above scenario can be solved, but since the number of resources scheduled by the UE is reduced, the throughput of the UE is also affected, especially in the rail transit scenario, and in most cases, the ICIC is not required. It is only needed in a few cases where the train meets. In this case, if the ICIC is turned on all the way, it will inevitably cause waste of the frequency band resources. Therefore, according to the characteristics of the rail transit scene, it is necessary to propose a more efficient method to solve the problem between trains. Interference problem.

Related terms:

Summary of the invention

The technical problem to be solved by the present invention is that in the LTE rail transit scenario, in order to solve the co-channel interference between neighboring cells, the ICIC is turned on, but the user throughput is degraded, and the service indicators cannot meet the demand, thereby affecting the user service experience.

The technical solution adopted by the invention is an anti-interference method for a rail transit wireless communication system. According to the fixed trajectory of the train vehicle terminal, the mobility has a fixed regularity, and the phase is dynamically staggered by monitoring the number of users in the neighboring cell. The frequency band of the user at the edge of the neighboring cell, or the frequency band of the user of the neighboring cell edge is periodically offset according to the law of train movement.

The system dynamically monitors the frequency band of the neighboring cell edge user by monitoring the number of neighboring cell users, including monitoring, by the base station, the number of neighboring cell users and the neighboring cell user camped by the neighboring cell, and performing periodic update if When the number of resident users of the cell is >0 and the number of resident users of the neighboring cell is >0, the joint scheduling with the neighboring cell or the ICIC is turned on to offset the frequency bands of the users on both sides;

The frequency band of the neighboring cell edge user is periodically offset according to the train movement rule, and the base station compares the current train occurrence time with the neighboring cell train occurrence time to identify all coincident time periods.

Moreover, when the frequency band of the neighboring cell edge user is dynamically staggered by monitoring the number of neighboring cell users, the base station measures the number of resident users of the jurisdictional cell, determines whether the number of resident users is 0 or 1, and places the resident The number of users left is fed back to each neighborhood.

Moreover, when the frequency band of the neighboring cell edge user is dynamically staggered by monitoring the number of neighboring cell users, the implementation manner includes the following steps:

1) The base station measures the number of resident users of its jurisdiction cell, determines whether the number of resident users is 0 or 1, and feeds back the number of resident users in the cell to each neighboring cell;

2) The base station maintains the number of users in the cell, and periodically updates according to the measurement result; the base station maintains the number of neighboring cell users that are fed back in the neighboring cell, and performs periodic update; as long as the number of users in any neighboring cell is non-zero , then the number of neighboring resident users is set to 1;

3) The base station determines whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

4) If the judgment result is satisfied in step 3), the joint scheduling with the neighboring cell or the ICIC is turned on to stagger the frequency bands of the users on both sides;

5) The base station determines whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

6) If the result of the determination in step 5) is not satisfied, the joint scheduling or ICIC with the neighboring cell is closed.

Moreover, when the frequency band of the user of the neighboring cell edge is periodically offset according to the law of train movement, the implementation manner includes the following steps:

1) According to the timetable of the orbital operation, the time period of the following vehicles of each base station is counted;

2) Compare the occurrence time of the train in the residential area with the occurrence time of the train in the neighboring cell, and identify all coincident time periods;

3) The base station performs interference coordination according to the identified coincidence period, and starts joint scheduling or ICIC with the neighboring area during the running to the corresponding time period.

Moreover, joint scheduling with the neighboring cell or ICIC is initiated according to the type supported by the rail transit vehicle wireless communication system.

The invention also provides an anti-interference device for a rail transit wireless communication system, which is characterized in that the operation track of the train vehicle terminal is fixed and the mobility has a fixed regularity, and the neighbors are dynamically shifted by monitoring the number of resident users of the neighboring cell. The frequency band of the user at the edge of the cell, or the frequency band of the user of the neighboring cell edge is periodically offset according to the law of train movement, including the following modules,

The resident judging module is configured to dynamically shift the frequency band of the neighboring cell edge user by monitoring the number of neighboring cell users, including monitoring, by the base station, the number of the user of the cell and the neighboring cell user camped by the neighboring cell, and Perform periodic update. If the number of users in the cell is >0 and the number of neighbors in the neighboring cell is >0, the joint scheduling with the neighboring cell or ICIC is enabled to stagger the frequency bands of the users on both sides;

The time period judging module is configured to periodically shift the frequency bands of the neighboring cell edge users according to the train movement rule, and the base station compares the present train occurrence time with the neighboring cell train occurrence time to identify all coincident time periods.

Moreover, the resident determination module includes the following units,

The first unit is configured to measure, by the base station, the number of resident users of the jurisdiction cell, determine whether the number of the resident users is 0 or 1, and feed back the number of the resident users in the cell to each neighboring cell;

The second unit is used by the base station to maintain the number of users in the cell, and periodically updates according to the measurement result; the base station maintains the number of neighboring cell users that are fed back in the neighboring cell, and performs periodic update; as long as any neighboring area resides The number of users is not 0, then the number of neighboring users is set to 1;

The third unit is used by the base station to determine whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

The fourth unit is configured to: if the judgment result of the third unit is satisfied, start joint scheduling with the neighboring cell or ICIC to stagger the frequency bands of the two users;

The fifth unit is used by the base station to determine whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

The sixth unit is configured to close the joint scheduling or ICIC with the neighboring cell if the fifth unit determines that the result is not satisfied.

Moreover, the time period judging module includes the following units,

a first unit, configured to calculate a time period of occurrence of the following vehicles in each base station according to a timetable of the orbit operation;

The second unit is configured to compare the occurrence time of the train in the local area with the occurrence time of the train of the neighboring cell, and identify all coincident time periods;

The third unit is configured to perform interference coordination by the base station according to the identified coincidence period, and start joint scheduling or ICIC with the neighboring area during the running to the corresponding time period.

The invention proposes a solution for solving the problem of co-channel interference caused by the approach of the trains of adjacent cells in the LTE rail transit communication scenario. According to the fixed trajectory of the train vehicle terminal, the mobility has a very fixed regularity. By monitoring the number of users in the neighboring cell, the frequency band of the user of the neighboring cell is dynamically staggered, or the train timetable is imported for statistically. The frequency band of the user at the edge of the neighboring cell. It avoids the waste of frequency resources caused by frequency resource limitation of users throughout the whole process, and is a more efficient method for solving interference problems.

The advantages of the invention are:

1. Using the monitoring of the number of users in the neighboring cell to dynamically shift the frequency band of the user of the neighboring cell edge;

2. Using the imported train schedule to perform statistics to periodically shift the frequency band of the user of the adjacent cell edge;

3. Intersect between adjacent base stations, and notify the neighbor base stations of the respective user conditions and scheduling policies.

The invention is simple, efficient and precise, does not require additional hardware investment, has important market value, and is of great significance to the leading position of related industries in the world.

DRAWINGS

1 is a schematic diagram of a prior art rail transit vehicle communication system;

2 is a schematic diagram of switching in the prior art;

FIG. 3 is a flowchart of processing a user occupancy number of a neighboring cell according to an embodiment of the present invention.

4 is a flow chart showing the process of using the imported train schedule in accordance with an embodiment of the present invention.

Figure 5 is a schematic diagram of an embodiment of the present invention.

Detailed ways

The above-mentioned objects, features, and advantages of the embodiments of the present invention will become more apparent and understood. For further details.

Referring to FIG. 5, the present invention provides an anti-interference scheme for a wireless communication system for a rail transit: the base station monitors the resident status of the user in the local cell and the neighboring cell or identifies the interference risk period according to the user movement rule; and performs the monitoring result or the risk period according to the monitoring result or the risk period. It is determined that if the condition satisfies the dynamic open anti-interference strategy; if the condition does not satisfy the open condition, it returns to the normal resource allocation strategy.

Preferably, the interference risk period is identified according to the user movement rule in advance, including statistics by importing the train schedule, and the frequency band of the neighboring cell edge user can be conveniently and regularly timed when the scene is used. If there is no pre-statistical period, the base station monitors the resident status of the user and the neighboring cell in real time when the scenario is used.

Embodiment 1: Dynamically staggering the frequency bands of adjacent small and user-edge users by monitoring the number of users in the neighboring cell, see Figure 3:

2) The base station maintains the number of users in the cell, and performs periodic update according to the measurement result. As long as the number of the resident users in the cell is not 0, the number of the resident users in the cell is set to 1; and the neighboring cell user that the base station feeds back to the neighboring cell The number of hosts is maintained and periodically updated; as long as the number of resident users in any neighboring cell is non-zero, the number of neighboring resident users is set to 1.

3) The base station determines whether the data it maintains meets the following two conditions:

The number of users in this cell >0

Neighbor cell user resident number>0

4) If the above conditions are met, the joint scheduling with the neighboring cell or the ICIC is opened to stagger the frequency band joint scheduling of the users on both sides for the same frequency band resource, and the edge users of the adjacent two cells are uniformly allocated, which is a dynamic scheduling. In the process, after a frequency band is occupied by the previous UE, the UE can only use the remaining frequency bands.

The ICIC is that two neighboring cells use only a part of the total frequency band to the respective edge UEs, and the frequency resources used by the two sides of the UE are not coincident. The two frequency bands are usually agreed in advance.

These two schemes are staggered by the user band of the neighboring cell. ICIC is simpler and more common, and the joint scheduling implementation is more complicated. In the specific implementation, the specific implementation is implemented according to the type supported by the wireless communication system of the rail transit vehicle, and usually the ICIC is easier to implement.

Joint scheduling can achieve greater performance gains, but implementation is more difficult than ICIC.

5) The base station determines whether the data it maintains meets the following two conditions:

The number of users in this cell >0

Neighbor cell user resident number>0

6) If not, close the joint scheduling or ICIC with the neighboring cell, and perform a common resource allocation scheme, that is, all frequency bands of the cell can be allocated to the UE, without limitation.

Embodiment 2: periodically shifting the frequency band of the user of the neighboring cell edge by counting the timetable of the train

In the rail transit scene, due to the fixed trajectory and time of the train, according to the train schedule, the train will be at a fixed position at the corresponding time. If the base station masters this law, then it can accurately meet the time of the train encounter. Timing to initiate joint scheduling or ICIC with neighbors. Referring to Figure 4, the specific steps are as follows:

1) According to the timetable of the orbital operation, the time period of the following vehicles of each base station is counted.

2) Compare the occurrence time of the train in the residential area with the occurrence time of the train in the neighboring cell, and identify all coincident time periods. These time periods indicate that there are trains in the two adjacent cells, and there is the possibility of interference. Interference coordination is needed during these time periods.

3) The base station performs interference coordination according to the coincident time period identified in the previous two steps, and starts joint scheduling or ICIC with the neighboring area when the clock runs to the corresponding time period.

In a specific implementation, the method provided by the present invention can realize an automatic operation process based on software technology, and can also implement a corresponding device in a modular manner: an anti-interference device for a rail transit wireless communication system, which is used for running according to a train vehicle terminal The trajectory is fixed, and the mobility has a fixed regularity. The frequency band of the neighboring cell edge user is dynamically staggered by monitoring the number of neighboring cell users, or the frequency band of the neighboring cell edge user is regularly timed according to the train movement law, including the following modules. ,

Further, the resident determination module includes the following units,

The number of users in this cell >0

Neighbor cell user resident number>0

The number of users in this cell >0

Neighbor cell user resident number>0

Further, the period determining module includes the following units,

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and modifications made without departing from the spirit and scope of the present invention. Simplification should be an equivalent replacement and is included in the scope of the present invention.

Claims

An anti-interference method for a rail transit wireless communication system, characterized in that: according to the fixed trajectory of the train vehicle terminal, the mobility has a fixed regularity, and dynamically shifts the edge of the adjacent cell by monitoring the number of resident users of the neighboring cell. The frequency band of the user, or the frequency band of the user of the neighboring cell edge is periodically shifted according to the law of train movement,

The system dynamically monitors the frequency band of the neighboring cell edge user by monitoring the number of neighboring cell users, including monitoring, by the base station, the number of neighboring cell users and the neighboring cell user camped by the neighboring cell, and performing periodic update if When the number of resident users of the cell is >0 and the number of resident users of the neighboring cell is >0, the joint scheduling with the neighboring cell or the ICIC is turned on to offset the frequency bands of the users on both sides;

The frequency band of the neighboring cell edge user is periodically offset according to the train movement rule, and the base station compares the current train occurrence time with the neighboring cell train occurrence time to identify all coincident time periods.
The anti-interference method for a rail transit wireless communication system according to claim 1, wherein when the frequency band of the neighboring cell edge user is dynamically staggered by monitoring the number of neighboring cell users, the base station measures the jurisdiction of the cell. The number of resident users is determined, and the number of resident users is 0 or 1, and the number of resident users in the cell is fed back to each neighboring cell.
The anti-interference method for a rail transit wireless communication system according to claim 2, wherein when the frequency band of the neighboring cell edge user is dynamically shifted by monitoring the number of neighboring cell users, the implementation manner includes the following steps:

1) The base station measures the number of resident users of its jurisdiction cell, determines whether the number of resident users is 0 or 1, and feeds back the number of resident users in the cell to each neighboring cell;

2) The base station maintains the number of users in the cell, and periodically updates according to the measurement result; the base station maintains the number of neighboring cell users that are fed back in the neighboring cell, and performs periodic update; as long as the number of users in any neighboring cell is non-zero , then the number of neighboring resident users is set to 1;

3) The base station determines whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

4) If the judgment result is satisfied in step 3), the joint scheduling with the neighboring cell or the ICIC is turned on to stagger the frequency bands of the users on both sides;

5) The base station determines whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

6) If the result of the determination in step 5) is not satisfied, the joint scheduling or ICIC with the neighboring cell is closed.
The anti-interference method for a rail transit wireless communication system according to claim 1, wherein when the frequency band of the neighboring cell edge user is periodically shifted according to the train movement rule, the implementation manner includes the following steps:

1) According to the timetable of the orbital operation, the time period of the following vehicles of each base station is counted;

2) Compare the occurrence time of the train in the residential area with the occurrence time of the train in the neighboring cell, and identify all coincident time periods;

3) The base station performs interference coordination according to the identified coincidence period, and starts joint scheduling or ICIC with the neighboring area during the running to the corresponding time period.
The anti-interference method for a rail transit wireless communication system according to claim 1 or 2 or 3 or 4, characterized in that the joint scheduling or ICIC with the neighboring cell is turned on according to the type supported by the rail transit vehicle wireless communication system.
An anti-jamming device for a wireless communication system for rail transit, characterized in that: according to the fixed trajectory of the train vehicle terminal, the mobility has a fixed regularity, and dynamically shifts the adjacent by monitoring the number of resident users of the neighboring cell. The frequency band of the user at the edge of the cell, or the frequency band of the user of the neighboring cell edge is periodically offset according to the law of train movement, including the following modules,

The resident judging module is configured to dynamically shift the frequency band of the neighboring cell edge user by monitoring the number of neighboring cell users, including monitoring, by the base station, the number of the user of the cell and the neighboring cell user camped by the neighboring cell, and Perform periodic update. If the number of users in the cell is >0 and the number of neighbors in the neighboring cell is >0, the joint scheduling with the neighboring cell or ICIC is enabled to stagger the frequency bands of the users on both sides;

The time period judging module is configured to periodically shift the frequency bands of the neighboring cell edge users according to the train movement rule, and the base station compares the present train occurrence time with the neighboring cell train occurrence time to identify all coincident time periods.
The anti-interference device for a rail transit wireless communication system according to claim 6, wherein when the frequency band of the neighboring cell edge user is dynamically staggered by monitoring the number of neighboring cell users, the base station measures the jurisdiction of the cell The number of resident users is determined, and the number of resident users is 0 or 1, and the number of resident users in the cell is fed back to each neighboring cell.
The anti-jamming device for a rail transit wireless communication system according to claim 7, wherein the resident judging module comprises the following unit,

The first unit is configured to measure, by the base station, the number of resident users of the jurisdiction cell, determine whether the number of the resident users is 0 or 1, and feed back the number of the resident users in the cell to each neighboring cell;

The second unit is used by the base station to maintain the number of users in the cell, and periodically updates according to the measurement result; the base station maintains the number of neighboring cell users that are fed back in the neighboring cell, and performs periodic update; as long as any neighboring area resides The number of users is not 0, then the number of neighboring users is set to 1;

The third unit is used by the base station to determine whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

The fourth unit is configured to: if the judgment result of the third unit is satisfied, start joint scheduling with the neighboring cell or ICIC to stagger the frequency bands of the two users;

The fifth unit is used by the base station to determine whether the maintained data meets the following two conditions simultaneously:

The number of users in this cell >0

Neighbor cell user resident number>0

The sixth unit is configured to close the joint scheduling or ICIC with the neighboring cell if the fifth unit determines that the result is not satisfied.
The anti-interference device for a rail transit wireless communication system according to claim 6, wherein the time period judging module comprises the following unit,

a first unit, configured to calculate a time period of occurrence of the following vehicles in each base station according to a timetable of the orbit operation;

The second unit is configured to compare the occurrence time of the train in the local area with the occurrence time of the train of the neighboring cell, and identify all coincident time periods;

The third unit is configured to perform interference coordination by the base station according to the identified coincidence period, and start joint scheduling or ICIC with the neighboring area during the running to the corresponding time period.
The anti-jamming device for a rail transit wireless communication system according to claim 6 or 7 or 8 or 9, wherein the joint scheduling or ICIC with the neighboring cell is turned on according to the type supported by the rail transit vehicle wireless communication system.