JP6785682B2 - Wireless communication system - Google Patents

Description

The present invention relates to a wireless communication system such as a train radio system that performs wireless communication between a mobile station on a mobile body and a plurality of base stations, and particularly a wireless communication system having a function of the mobile station automatically switching the wireless system. It is about.

The train is equipped with and operated a wireless communication system (hereinafter, also referred to as "train radio system") as a means of contacting the operation command center and arranging relief in an emergency. In the train radio system, the frequency used for wireless communication is assigned to each line section divided within a certain range, and when the train travels across the line sections, the wireless communication channel corresponds to the frequency of each line section. I'm switching to one.

In the conventional train radio system, when a train passes through a point where the radio communication channel is switched, the train crew manually switches the radio communication channel, but there is a concern about human error such as omission of switching. Therefore, there is a need for a system that automatically switches wireless communication channels.

Patent Document 1 is a wireless communication system that performs wireless communication between a mobile station on a mobile body (train) and a base station on the ground, and a switching base station that transmits a switching signal is newly installed on the ground. A wireless communication system capable of automatically switching wireless communication channels is disclosed.

More specifically, the above-mentioned wireless communication system is a wireless communication system capable of automatically switching wireless communication channels by using two types of switching base stations (notice base station and fixed base station). Wireless communication when the mobile station receives the switching signal (confirmed signal) transmitted by the confirmed base station after receiving the switching signal (notice signal) transmitted by the advance notice base station near the switching point of the wireless communication channel. It is a wireless communication system that switches channels.

The technique described in Patent Document 1 cannot cope with a case where a mobile station cannot receive at least one of a warning signal and a confirmation signal due to some adverse effect such as a device failure, and a wireless communication channel switching omission occurs. Therefore, Patent Document 2 discloses a wireless communication system capable of suppressing omission of switching of a wireless communication channel by using a forced base station in addition to the advance notice base station and the fixed base station. In the technique described in Patent Document 2, the mobile station forcibly switches the wireless communication channel when it receives the switching signal (forced signal) transmitted by the forced base station.

Further, in the techniques described in Patent Document 1 and Patent Document 2, wireless communication is performed without increasing the radio frequency used by transmitting a normal signal and a switching signal used for the operation purpose of a train radio system in a time-divided manner. The channel switching is realized. This time division is realized by allocating the switching signal to one frame in the super frame by utilizing the fact that the mobile station and the base station are synchronized in a unit frame consisting of multiple frames (also called "super frame"). doing.

In the above train radio system, when a train travels across lines with different frequencies, the mobile station can automatically switch the wireless communication channel while suppressing the omission of switching the wireless communication channel. ..

JP-A-2010-10865 JP 2015-159389

In recent years, the number of railway operators that are shifting the wireless system of train radio systems from analog systems to digital systems is increasing, and on routes that operate across multiple railway operators, the management section for each railway operator The wireless system may differ depending on the type. Further, even in the management section of the same railway company, there are cases where the wireless system is a mixture of analog system lines and digital system lines. Since the analog wireless system and the digital wireless system are independent wireless standards, the wireless system of the mobile station must be switched when the train travels across different wireless system lines. Therefore, there is a demand for a wireless communication system having a function of automatically switching the wireless system. However, since the conventional wireless communication system is a system for switching wireless communication channels, there is a problem that it cannot support switching of wireless systems.

Therefore, the present invention has been made to solve the above-mentioned problems, and automatically switches the wireless system in a mobile station on a mobile body that moves in a place where two wireless systems coexist. It is an object of the present invention to provide a wireless communication system capable of performing.

The wireless communication system according to the present invention is a wireless communication system that performs wireless communication between a mobile station on a mobile body and a plurality of base stations. The plurality of base stations include a first normal base station, a second normal base station, and a plurality of switching base stations. The first normal base station transmits and receives normal signals to and from the mobile station by the first wireless system in the first communication area. The second normal base station transmits / receives a normal signal to and from the mobile station in the second communication area by a second radio system different from the first radio system. The plurality of switching base stations transmit a plurality of switching signals, respectively. When the mobile station receives a plurality of switching signals in a normal manner, the mobile station switches between the first radio system and the second radio system for transmitting and receiving normal signals. The plurality of switching base stations include a first forced base station and a second forced base station that transmit a first forced signal and a second forced signal as switching signals, respectively. When the mobile station receives the first forced signal when the wireless system is the first wireless system, the mobile station switches the wireless system to the second wireless system, and when the wireless system is the second wireless system, the second forced signal. Is received, the wireless system is switched to the first wireless system. The first compulsory base station transmits a first compulsory signal and a first synchronization signal for the mobile station to perform wireless communication by the first radio system in the second communication area by the first radio system. The second compulsory base station transmits a second compulsory signal and a second synchronization signal for the mobile station to perform wireless communication by the second radio system within the first communication area by the second radio system. The mobile station receives the first forced signal using the first sync signal transmitted by the first forced base station in the second communication area, and the second sync transmitted by the second forced base station in the first communication area. The second forced signal is received using the signal.

According to the wireless communication system of the present invention, when a mobile station receives a plurality of switching signals transmitted from a plurality of switching base stations in a normal manner, the mobile station transmits and receives a normal signal as the first radio. Switch between the system and the second wireless system. As a result, the wireless system can be automatically switched in the mobile station on the mobile body that moves in a place where the two wireless systems coexist.

It is a figure which shows the whole structure of the wireless communication system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the mobile station which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the communication frame which concerns on Embodiment 1 of this invention. It is a flowchart which shows the operation which the mobile station which concerns on Embodiment 1 of this invention switches a wireless system. It is a figure which shows the whole structure of the wireless communication system which concerns on Embodiment 2 of this invention. It is a flowchart which shows the operation which the mobile station which concerns on Embodiment 2 of this invention switches a wireless system. It is a figure which shows the whole structure of the wireless communication system which concerns on Embodiment 3 of this invention. It is a figure which shows the structure of the communication frame which concerns on Embodiment 3 of this invention. It is a figure which shows the whole structure of the wireless communication system which concerns on Embodiment 4 of this invention. It is a figure which shows the structure of the communication frame which concerns on Embodiment 4 of this invention. It is a figure for demonstrating the state transition of the mobile station which is restricted in the interference zone which concerns on Embodiment 5 of this invention. It is a figure which shows the state transition of the mobile station in the interference zone 1d which concerns on Embodiment 5 of this invention. It is a figure which shows the state transition of the mobile station in the interference zone 1e which concerns on Embodiment 5 of this invention. It is a flowchart which shows the operation which the mobile station which concerns on Embodiment 5 of this invention switches a wireless system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
<Overall configuration of wireless communication system>
FIG. 1 is a diagram showing an example of the overall configuration of the wireless communication system 100A according to the first embodiment of the present invention. The wireless communication system 100A includes a mobile station 21 on the mobile body 2, a first normal base station 30, a first notice base station 31, a first fixed base station 32, a second notice base station 51, and a second fixed base station 52. Is a system for wireless communication. In the present embodiment, the wireless communication system 100A is a train radio system, and the mobile body 2 is a train traveling on the line 1. In the example of FIG. 1, the moving body 2 travels on the route 1 toward the right or left of the figure.

As shown in FIG. 1, the wireless communication system 100A has a first communication area 1a and a second communication area 1b. The first communication area 1a is a normal signal (a signal used for operational purposes such as communication with an operation command center) transmitted by the first normal base station 30 in the first wireless system. Hereinafter, it is also referred to as a "first normal signal". Indicates the communication area where (call) reaches. The second communication area 1b is a normal signal (a signal used for operational purposes such as communication with an operation command center) transmitted by the second normal base station 50 by the second radio system. Hereinafter, it is also referred to as a "second normal signal". Indicates the communication area where (call) reaches.

The first communication area 1a and the second communication area 1b partially overlap each other, and the third communication area 1c, which is the overlapping area, is the first normal signal and the second normal signal transmitted by the first normal base station 30. It is a communication area where both the second normal signal transmitted by the normal base station 50 can reach. The first wireless system and the second wireless system are independent wireless systems having different wireless standards, and the first wireless system and the second wireless system are, for example, analog and digital wireless systems, respectively.

Line 1 straddles the first communication area 1a, the third communication area 1c, and the second communication area 1b, and the mobile body 2 passes from the first communication area 1a through the third communication area 1c to the second communication area 1b. Alternatively, it moves from the second communication area 1b through the third communication area 1c to the first communication area 1a. Therefore, in the wireless communication system 100A according to the present embodiment, the mobile station 21 on the mobile body 2 sets a wireless system for transmitting and receiving a normal signal according to a communication area between the first wireless system and the second wireless system. It has a function to switch automatically.

The first normal base station 30 is systematically synchronized with the first notice base station 31 and the first fixed base station 32 via the first line 3D. The first notice base station 31 transmits the first notice signal 421 to the area 31a in the first communication area 1a by the first radio system. The first fixed base station 32 transmits the first fixed signal 422 to the area 32a in the first communication area 1a by the first radio system.

Each of the first warning signal 421 and the first confirmation signal 422 is a switching signal for switching the wireless system in which the mobile station 21 transmits / receives a normal signal from the first wireless system to the second wireless system. Is also called a "first switching signal". Further, each of the first notice base station 31 and the first fixed base station 32 is a switching base station that transmits a first switching signal, and each of them is also referred to as a "first switching base station" below.

The second normal base station 50 is systematically synchronized with the second notice base station 51 and the second fixed base station 52 via the second line 5D. The second notice base station 51 transmits the second notice signal 413 to the area 51a in the second communication area 1b by the second radio system. The second fixed base station 52 transmits the second fixed signal 412 to the area 52a in the second communication area 1b by the second radio system.

Each of the second warning signal 413 and the second confirmation signal 412 is a switching signal for switching the wireless system in which the mobile station 21 transmits / receives a normal signal from the second wireless system to the first wireless system. Is also called a "second switching signal". Further, each of the second advance notice base station 51 and the second fixed base station 52 is a switching base station that transmits a second switching signal, and each of them is also referred to as a "second switching base station" below.

The mobile station 21 normally uses the first switching signals 421 and 422 transmitted from the first switching base stations 31 and 32 and the second switching signals 413 and 412 transmitted from the second switching base stations 51 and 52, respectively. When the signal is received in the above mode, the wireless system for transmitting and receiving the normal signal is switched between the first wireless system and the second wireless system. Specifically, when the mobile station 21 receives the first confirmation signal 422 after receiving the first notice signal 421, the mobile station 21 switches the radio system for transmitting and receiving the normal signal from the first radio system to the second radio system. .. Further, when the mobile station 21 receives the second confirmation signal 412 after receiving the second warning signal 413, the mobile station 21 switches the radio system for transmitting and receiving the normal signal from the second radio system to the first radio system.

As described above, the mobile station 21 switches the radio system when the first warning signal 421 and the first confirmation signal 422 or the second warning signal 413 and the second confirmation signal 412 are received in the normal order, so that the mobile station 21 is a mobile station. The area where each switching signal is transmitted is appropriately set so that the 21 can switch the wireless system according to the communication area.

For example, the area 31a in which the first warning signal 421 is transmitted and the area 32a in which the first confirmation signal 422 is transmitted are compared with the wireless switching point (near the third communication area 1c) in the first communication area 1a. It is set to a close position. Further, in the areas 31a and 32a, the mobile station 21 on the mobile body 2 moving from the first communication area 1a to the second communication area 1b sends the first warning signal 421 and the first confirmation signal 422 in that order. It is set to a position where it can be received.

On the other hand, the area 51a in which the second warning signal 413 is transmitted and the area 52a in which the second confirmation signal 412 is transmitted are set at positions relatively close to the switching point of the wireless system in the second communication area 1b. Further, in the areas 51a and 52a, the mobile station 21 on the mobile body 2 moving from the second communication area 1b toward the first communication area 1a sends the second warning signal 413 and the second confirmation signal 412 in that order. It is set to a position where it can be received. In the example of FIG. 1, the area 32a and the area 52a are set in the third communication area 1c, but the positions of the area 32a and the area 52a are not limited to this.

The first normal base station 30, the first notice base station 31, and the first fixed base station 32, which perform wireless communication by the first wireless system, each transmit signals at frequency f1, but the respective base stations are synchronized. Taking advantage of this, each signal is transmitted separately in time and space, so there is no interference. Further, although each of the second normal base station 50, the second notice base station 51, and the second fixed base station 52, which perform wireless communication by the second wireless system, transmit signals at the frequency f2, the respective base stations Utilizing the fact that they are synchronized, each signal is transmitted separately in time and space, so that there is no interference. Since the frequencies f1 and f2 have different frequencies, the signal of the first radio system and the signal of the second radio system do not interfere with each other.

<Mobile station configuration>
FIG. 2 is a block diagram showing an example of the configuration of the mobile station 21 according to the first embodiment of the present invention. As shown in FIG. 2, the mobile station 21 has a first mobile station 21a capable of receiving a first normal signal and a first switching signal (hereinafter, also referred to as a “first signal”), a second normal signal, and a second normal signal. It has a second mobile station 21b capable of receiving two switching signals (hereinafter, also referred to as “second signal”). As a result, the mobile station 21 is in a state where it can always receive both the first signal and the second signal, but for operation (that is, transmission / reception of a normal signal), either the first mobile station 21a or the second mobile station 21b Use only one.

The mobile station 21 further includes a switching unit 21c, a determination unit 21d, and a storage unit 21e. After receiving the first signal and demodulating it, the first mobile station 21a inputs the first switching signal as the first switching data 21ad to the determination unit 21d. After receiving the second signal and demodulating it, the second mobile station 21b inputs the second switching signal as the second switching data 21bd to the determination unit 21d. The determination unit 21d determines the method to be used for the operation of the wireless communication system by referring to the information of the first switching data 21ad and the second switching data 21bd and the parameters stored in the storage unit 21e, and determines the result. Input to the switching unit 21c.

When the determination unit 21d inputs the result that the method used for operation is the first wireless method, the switching unit 21c inputs the enable signal 21ce to the first mobile station 21a. On the other hand, when the result that the method used for operation is the second radio method is input from the determination unit 21d, the switching unit 21c inputs the enable signal 21ce to the second mobile station 21b.

When the enable signal 21ce is input to the first mobile station 21a, the first mobile station 21a processes the first normal signal as an operation signal of the wireless communication system, and the second mobile station to which the enable signal 21ce is not input is processed. 21b does not process the operation signal. On the other hand, when the enable signal 21ce is input to the second mobile station 21b, the second mobile station 21b processes the second normal signal as an operation signal of the wireless communication system, and the first enable signal 21ce is not input. The mobile station 21a does not process the operation signal. The mobile station 21 is in a state where it can always receive the signals of the first wireless system and the second wireless system, but by processing the normal signal of either wireless system as an operation signal, the wireless system is automatically set. It is possible to switch.

<Communication frame configuration>
FIG. 3 is a diagram showing an example of the configuration of the communication frame according to the first embodiment of the present invention. In FIG. 3, the mobile body 2 is in the first communication area 1a, and the communication performed between the first mobile station 21a and the first normal base station 30 and the first switching base stations 31 and 32 is performed. Shows the configuration of the communication frame. Further, FIG. 3 also shows a block diagram showing the configuration of the first mobile station 21a.

As described above, since the first normal base station 30 and the first switching base stations 31 and 32 transmit signals at the same frequency f1 in the same space, interference occurs unless the signals are time-divided. To do. Therefore, as shown in FIG. 3, the configuration of the communication frame in the communication performed between the first mobile station 21a, the first normal base station 30, and the first switching base stations 31 and 32 includes a plurality of frames F1 to. It has a super frame structure in which communication is performed using a super frame SF composed of FN as a unit frame.

In this configuration, the first switching signal is assigned to one frame Fj1 in the super frame SF, and the first normal signal composed of the first operation signal and the first synchronization signal is assigned to the other frames. Timing control is performed so that these signals do not interfere with each other. Since the first normal base station 30 is synchronized with the first switching base stations 31 and 32 on the first line 3D, the start timing SFt of the super frame SF in each base station matches, and the first normal signal The timing control between and the first switching signal is accurate.

The first mobile station 21a has a first operation signal processing unit 21a1 that processes the first operation signal, a first synchronization signal processing unit 21a2 that processes the first synchronization signal, and a first switching signal that processes the first switching signal. It has a processing unit 21a3. If the first mobile station 21a cannot receive the first synchronization signal, it cannot perform superframe synchronization with each of the first normal base station 30, the first notice base station 31, and the first fixed base station 32, and communicates with each other. Cannot be established. That is, the first mobile station 21a can receive the first switching signal only when it is in the first communication area 1a where the first normal signal from the first normal base station 30 can be received. Similarly, in the second radio system, the second mobile station 21b can receive the second switching signal only when it is in the second communication area 1b.

The configuration of the second mobile station 21b and the configuration of the communication frame in the communication between the second mobile station 21b and the second normal base station 50 and the second switching base stations 51 and 52 by the second radio system are as described above. In the description, since it is the same as the one in which "first 1" is replaced with "second", the illustration and detailed description will be omitted.

<Wireless system switching operation>
FIG. 4 is a flowchart showing an operation in which the mobile station 21 according to the first embodiment of the present invention switches the wireless system. Hereinafter, with reference to the figure, a procedure of switching processing in which the mobile station 21 receives each switching signal and transmits / receives a normal signal is switched between the first wireless system and the second wireless system.

First, in step S0, step S1 is executed when the initial operating state of the mobile station 21, that is, the state of the mobile station 21 at the start of operation is the first operating state in which the wireless system is the first wireless system. .. On the other hand, when the initial operating state of the mobile station 21 is the second operating state in which the wireless system is the second wireless system, step S2 is executed. The initial operation state of the mobile station 21 is manually set by, for example, a user (when the mobile body 2 is a train as in the present embodiment, its crew), and step S1 or step S2 is performed based on the setting contents. Will be executed.

In the following, for convenience of explanation, the wireless system for starting the operation of the mobile station 21 is the first wireless system, and the mobile body 2 moves in the direction from the first communication area 1a to the second communication area 1b, and the mobile station 21 The case where the wireless system is switched from the first wireless system to the second wireless system will be described.

As described above, since the mobile station 21 is in the first wireless system at the start of operation, step S1 is executed after step S0. In step S1, the mobile station 21 enters the first standby state in which the first normal signal is processed as an operation signal. Then, in step S5, the determination unit 21d determines whether or not the mobile station 21 has received the first warning signal 421. In the determination unit 21d, for example, when the first switching data 21ad is input from the first mobile station 21a, the mobile station 21 is first set based on the first switching data 21ad and the parameters stored in the storage unit 21e. It is determined whether or not the warning signal 421 has been received.

In step S5, when it is determined that the mobile station 21 has received the first warning signal 421, step S7 is executed. On the other hand, if it is determined that the mobile station 21 has not received the first warning signal 421, step S1 is executed again. Until it is determined in step S5 that the mobile station 21 has received the first warning signal 421, the processes of steps S1 and S5 are repeatedly executed, for example, at predetermined time intervals.

In step S7, the state of the mobile station 21 transitions to the first confirmed signal standby state that waits for the first confirmed signal 422. Then, in step S11, the determination unit 21d determines whether or not the mobile station 21 has received the first confirmation signal 422. For example, when the first switching data 21ad is input from the first mobile station 21a, the determination unit 21d outputs the first confirmation signal 422 based on the first switching data 21ad and the parameters stored in the storage unit 21e. Determine if it has been received.

In step S11, when it is determined that the mobile station 21 has received the first confirmation signal 422, step S13 is executed. On the other hand, if it is determined that the mobile station 21 has not received the first confirmation signal 422, step S1 is executed again, and the state of the mobile station 21 returns to the first standby state.

In step S13, the mobile station 21 switches the wireless system from the first wireless system to the second wireless system. Specifically, when the switching unit 21c inputs the enable signal 21ce to the second mobile station 21b, the mobile station 21 switches the wireless system for transmitting and receiving normal signals from the first wireless system to the second wireless system. Then, in step S2, the mobile station 21 enters the second standby state in which the second normal signal is processed as an operation signal. The processing of steps S2, S6, S8, S12, and S14 is the same as the case where "first" is replaced with "second" in the processing of steps S1, S5, S7, S11, and S13 described above, respectively. Therefore, detailed description will be omitted.

As described above, in the wireless communication system 100A according to the present embodiment, when the mobile station 21 whose wireless system is the first wireless system receives the first warning signal 421 and then the first confirmation signal 422. , The wireless system for transmitting and receiving normal signals is switched from the first wireless system to the second wireless system. Further, when the mobile station 21 whose wireless system is the second wireless system receives the second confirmation signal 412 after receiving the second warning signal 413, the wireless system for transmitting and receiving the normal signal is changed from the second wireless system. Switch to the first wireless system. As a result, when the mobile body 2 moves across the communication areas of the two wireless systems, the mobile station 21 can automatically switch the wireless system.

<Embodiment 2>
Hereinafter, the wireless communication system according to the second embodiment of the present invention will be described. The wireless communication system according to the present embodiment can receive at least one of the first notice signal 421 and the first confirmation signal 422, and can also receive at least one of the second notice signal 413 and the second confirmation signal 412. It has a function to suppress omission of switching of the wireless system when it is not present.

FIG. 5 is a diagram showing an example of the overall configuration of the wireless communication system 100B according to the second embodiment of the present invention. As shown in FIG. 5, the wireless communication system 100B according to the present embodiment has a first compulsory base station 54 and a second compulsory base station 54 as compared with the wireless communication system 100A according to the first embodiment shown in FIG. A base station 34 is further provided. In the present embodiment, the mobile station 21 that has received the forced signal transmitted from each of the first forced base station 54 and the second forced base station 34 forcibly switches the wireless system. The same components as those described in the above-mentioned figures in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted. The same applies to the following figures.

The first forced base station 54 is systematically synchronized with the second notice base station 51 and the second fixed base station 52 via the second line 5D. The first forced base station 54 transmits the first forced signal 423 to the area 54a in the second communication area 1b by the second radio system. Since the first mobile station 21a cannot receive the first synchronization signal transmitted from the first normal base station 30 in the second communication area 1b, it is possible to establish super frame synchronization by the first radio system. The switching signal cannot be received by the first wireless system. On the other hand, in the second communication area 1b, the second synchronization signal transmitted from the second normal base station 50 can be received by the second mobile station 21b. Therefore, the first forced base station 54 enables communication with the mobile station 21 by transmitting the first forced signal 423 by the second radio system in the second communication area 1b.

The second forced base station 34 is systematically synchronized with the first notice base station 31 and the first fixed base station 32 via the first line 3D. Similar to the first forced base station 54, the second forced base station 34 communicates with the mobile station 21 by transmitting the second forced signal 411 to the area 34a in the first communication area 1a by the first radio system. It enables communication. At this time, since the first forced base station 54 transmits signals by the same wireless method as the second notice base station 51 and the second fixed base station 52, it is necessary to shift the transmission area so that the signals do not interfere with each other. There is. Further, since the second forced base station 34 transmits signals by the same wireless method as the first notice base station 31 and the first fixed base station 32, it is necessary to shift the transmission area so that the signals do not interfere with each other. is there.

The first forced signal 423 is a switching signal for switching the wireless system in which the mobile station 21 transmits and receives a normal signal from the first wireless system to the second wireless system, and is also referred to as a "first switching signal" below. Further, the first forced base station 54 is a switching base station that transmits a first switching signal, and is also referred to as a "first switching base station" below. Further, the second forced signal 411 is a switching signal for switching the wireless system in which the mobile station 21 transmits / receives a normal signal from the second wireless system to the first wireless system, and is also referred to as a "second switching signal" below. Call. Further, the second forced base station 34 is a switching base station that transmits a second switching signal, and is also referred to as a "second switching base station" below.

When the mobile station 21 receives the first forced signal 423 when the wireless system for transmitting and receiving the normal signal is the first wireless system, the mobile station 21 changes the wireless system for transmitting and receiving the normal signal from the first wireless system to the first wireless system. 2 Switch to wireless system. Further, when the mobile station 21 receives the second forced signal 411 when the wireless system for transmitting and receiving the normal signal is the second wireless system, the mobile station 21 uses the second wireless system as the wireless system for transmitting and receiving the normal signal. To switch to the first wireless system.

In the present embodiment, the first forced signal 423 is used in order to cope with the omission of switching from the first radio system to the second radio system by the first warning signal 421 and the first confirmation signal 422. Further, the second forced signal 411 is used in order to cope with the omission of switching from the second radio system to the first radio system by the second warning signal 413 and the second confirmation signal 412.

Therefore, the area where the first forced signal 423 and the second forced signal 411 are transmitted is appropriately set so that the mobile station 21 can switch the wireless system according to the communication area. For example, the area 54a in which the first forced signal 423 is transmitted is located relatively close to the wireless system switching point (near the boundary between the first communication area 1a and the second communication area 1b) in the second communication area 1b. Set. Further, the area 54a is a position where the moving body 2 moving from the first communication area 1a to the second communication area 1b can receive the first warning signal 421, the first confirmation signal 422, and the first forced signal 423 in that order. Is set to.

On the other hand, the area 34a in which the second forced signal 411 is transmitted is set, for example, at a position relatively close to the switching point of the wireless system in the first communication area 1a. Further, the area 34a is a position where the moving body 2 moving from the second communication area 1b toward the first communication area 1a can receive the second warning signal 413, the second confirmation signal 412, and the second forced signal 411 in that order. Is set to.

FIG. 6 is a flowchart showing an operation in which the mobile station 21 according to the second embodiment of the present invention switches the wireless system. As shown in FIG. 6, steps S3, S4, S9, and S10 are further provided as compared with the flowchart shown in FIG. 4 in the first embodiment.

First, in step S0, if the initial operating state of the mobile station 21 is the first operating state, Tep S1 is executed. On the other hand, when the initial operating state of the mobile station 21 is the second operating state, step S2 is executed.

In the following, for convenience of explanation, the wireless system for starting the operation of the mobile station 21 is the first wireless system, and the mobile body 2 moves in the direction from the first communication area 1a to the second communication area 1b, and the mobile station 21 The case where the wireless system is switched from the first wireless system to the second wireless system will be described.

As described above, since the mobile station 21 is in the first wireless system at the start of operation, step S1 is executed after step S0. In step S1, the mobile station 21 is in the first standby state. Then, in step S3, the determination unit 21d determines whether or not the mobile station 21 has received the first forced signal 423. In the determination unit 21d, for example, when the first switching data 21ad is input from the first mobile station 21a, the mobile station 21 is first set based on the first switching data 21ad and the parameters stored in the storage unit 21e. It is determined whether or not the forced signal 423 has been received.

In step S3, when it is determined that the mobile station 21 has received the first forced signal 423, step S13 is executed. In step S13, the mobile station 21 switches the wireless system from the first wireless system to the second wireless system.

On the other hand, if it is determined that the mobile station 21 has not received the first forced signal 423, step S5 is executed. In step S5, when it is determined that the mobile station 21 has received the first warning signal 421, step S7 is executed. On the other hand, if it is determined that the mobile station 21 has not received the first warning signal 421, step S1 is executed again. Steps S1, S3, S5 until it is determined in step S3 that the mobile station 21 has received the first forced signal 423 or in step S5 it is determined that the mobile station 21 has received the first warning signal 421. Is repeatedly executed, for example, at predetermined time intervals.

In step S7, the state of the mobile station 21 transitions to the first fixed signal standby state. Then, in step S9, the determination unit 21d determines whether or not the mobile station 21 has received the first forced signal 423. Since the content of the process in step S9 is the same as that in step S3, detailed description thereof will be omitted.

In step S9, when it is determined that the mobile station 21 has received the first forced signal 423, step S13 is executed. On the other hand, if it is determined that the mobile station 21 has not received the first forced signal 423, step S11 is executed.

In step S11, the determination unit 21d determines whether or not the mobile station 21 has received the first confirmation signal 422. In step S11, when it is determined that the mobile station 21 has received the first confirmation signal 422, step S13 is executed. On the other hand, if it is determined that the mobile station 21 has not received the first confirmation signal 422, step S1 is executed again, and the state of the mobile station 21 returns to the first standby state.

In step S13, the mobile station 21 switches the wireless system from the first wireless system to the second wireless system. Then, in step S2, the mobile station 21 is in the second standby state. In the processes of steps S2, S4, S6, S8, S10, S12, and S14, respectively, in the processes of steps S1, S3, S5, S7, S9, S11, and S13 described above, "first" is changed to "second." Since it is the same as the case of replacing with "~", detailed explanation is omitted.

As described above, in the wireless communication system 100B according to the present embodiment, when the mobile station 21 whose wireless system is the first wireless system receives the first forced signal 423 transmitted from the first forced base station 54. Forcibly switches the wireless system for transmitting and receiving normal signals from the first wireless system to the second wireless system. Further, when the mobile station 21 whose wireless system is the second wireless system receives the second forced signal 411 transmitted from the second forced base station 34, the wireless system that transmits / receives a normal signal is the second wireless system. Forcibly switches to the first wireless system. Therefore, even when at least one of the first warning signal 421 and the first confirmation signal 422 cannot be received, or at least one of the second warning signal 413 and the second confirmation signal 412 cannot be received, the wireless system is used. Switching omission can be suppressed.

<Embodiment 3>
Hereinafter, the wireless communication system according to the third embodiment of the present invention will be described. In the wireless communication system according to the present embodiment, the wireless system of the first switching base station that transmits the first switching signal is unified with the first wireless system, and the wireless system of the second switching base station that transmits the second switching signal. Is a wireless communication system unified with the second wireless system.

FIG. 7 is a diagram showing an example of the overall configuration of the wireless communication system 100C according to the third embodiment of the present invention. As shown in FIG. 7, in the wireless communication system 100C according to the present embodiment, the first forced base station 54 is replaced with the wireless communication system 100B according to the second embodiment shown in FIG. The forced base station 33 is provided, and the second forced base station 53 is provided in place of the second forced base station 34.

The first normal base station 30, the first notice base station 31, the first fixed base station 32, and the first forced base station 33 are systematically synchronized on the first line 3D. The first forced base station 33 transmits the first forced signal 423 to the area 33a in the second communication area 1b by the first radio system. Further, the second normal base station 50, the second notice base station 51, the second fixed base station 52, and the second forced base station 53 are systematically synchronized on the second line 5D. The second forced base station 53 transmits the first forced signal 423 to the area 53a in the first communication area 1a by the second radio system.

FIG. 8 is a diagram showing an example of the configuration of the communication frame according to the third embodiment of the present invention. FIG. 8 shows a configuration of a communication frame for communication between the first mobile station 21a, the first normal base station 30, the first notice base station 31, the first fixed base station 32, and the first forced base station 33. Shown. Further, FIG. 8 also shows a block diagram showing the configuration of the first mobile station 21a.

As shown in FIG. 8, the configuration of the communication frame in the communication between the first mobile station 21a and the first normal base station 30, the first notice base station 31 and the first fixed base station 32 in the present embodiment is , The same as in the first embodiment, the mobile station 21 receives the first synchronization signal from the first normal base station 30 in the first communication area 1a, and receives the first normal base station 30 and the first notice base station. The signal is received by superframe synchronization with each of 31 and the first fixed base station 32.

On the other hand, since the first forced base station 33 transmits the first forced signal 423 outside the first communication area 1a, the mobile station 21 is the first from the first normal base station 30 in the area where the first forced signal 423 reaches. 1 The synchronization signal cannot be received. Therefore, the mobile station 21 cannot receive the first forced signal 423 by performing superframe synchronization using the first synchronization signal from the first normal base station 30.

Therefore, in the present embodiment, as shown in FIG. 8, the first forced base station 33 transmits the first synchronization signal and the first operation dummy signal at a timing other than the frame Fj1 for transmitting the first switching signal. The first synchronization signal transmitted by the first forced base station 33 is the same as the first synchronization signal transmitted by the first normal base station 30, and the mobile station 21 is the first synchronized signal transmitted by the first forced base station 33. By receiving the 1 synchronization signal, superframe synchronization can be performed with the first forced base station 33 by the first radio system even outside the first communication area 1a. The first operation dummy signal is a dummy signal transmitted by the first forced base station 33 instead of the first operation signal transmitted by the first normal base station 30, and the mobile station 21 receives the first operation dummy signal. However, it is not processed as an operation signal.

The second compulsory base station 53 is in the first communication area 1a in the second radio system, as in the case where the "first" and "second" are replaced in the description of the first compulsory base station 33. The second forced signal 411, the second synchronization signal, and the second operation dummy signal are transmitted to the region 53a of the above. By receiving the second synchronization signal transmitted by the second forced base station 53, the mobile station 21 superframe synchronizes with the second forced base station 53 in the second wireless system even outside the second communication area 1b. can do.

As described above, in the wireless communication system 100C according to the present embodiment, the first forced base station 33 can transmit a signal by a wireless system different from that of the second advance notice base station 51 and the second fixed base station 52. It becomes. Further, the second forced base station 53 can transmit a signal by a radio system different from that of the first notice base station 31 and the first fixed base station 32. Therefore, it is not necessary to shift the positions of these base stations. Further, the switching of the unidirectional wireless system (switching from the first wireless system to the second wireless system or switching from the second wireless system to the first wireless system) can be realized by one type of wireless system.

<Embodiment 4>
Hereinafter, the wireless communication system according to the fourth embodiment of the present invention will be described. In the wireless communication system according to the present embodiment, the function of the second switching base station that transmitted the second switching signal by the second wireless system in the third embodiment is changed to the first switching signal by the first wireless system. The number of switching base stations is reduced by integrating with the first switching base station to transmit.

FIG. 9 is a diagram showing an example of the overall configuration of the wireless communication system 100D according to the fourth embodiment of the present invention. As shown in FIG. 9, in the wireless communication system 100D according to the present embodiment, the second notice base station 51 and the second confirmation are compared with the wireless communication system 100C according to the third embodiment shown in FIG. It does not have a base station 52 and a second forced base station 53, and the functions of these base stations are integrated into the first forced base station 33, the first fixed base station 32, and the first notice base station 31, respectively. Has been done.

The first normal base station 30, the first notice base station 31, the first fixed base station 32, and the first forced base station 33 are systematically synchronized on the first line 3D. The first notice base station 31 transmits the first notice signal 421 and the second forced signal 411 by the first radio system. The first fixed base station 32 transmits the first fixed signal 422 and the second fixed signal 412 by the first wireless system. The first forced base station 33 transmits the first forced signal 423 and the second warning signal 413 by the first radio system.

Further, in the present embodiment, the switching signal is classified into either the first switching signal group 42 or the second switching signal group 41. The first switching signal group 42 is composed of a first warning signal 421, a first confirmation signal 422, and a first forced signal 423. The second switching signal group 41 is composed of a second warning signal 413, a second confirmation signal 412, and a second forced signal 411. Each of the first notice base station 31, the first fixed base station 32, and the first forced base station 33 alternately transmits a signal belonging to the first switching signal group 42 and a signal belonging to the second switching signal group 41. To do. The timing of transmitting this signal will be described below.

FIG. 10 is a diagram showing an example of the configuration of the communication frame according to the fourth embodiment of the present invention. In FIG. 10, a communication frame configuration for communication between the first mobile station 21a and the first normal base station 30, the first notice base station 31, the first fixed base station 32, and the first forced base station 33 is performed. Is shown. Further, FIG. 10 also shows a block diagram showing the configuration of the first mobile station 21a.

As shown in FIG. 10, the communication frame in the present embodiment has a super frame configuration, and is divided into a super frame SF1 and a super frame SF2. Each of the first normal base station 30, the first notice base station 31, the first fixed base station 32, and the first forced base station 33 alternately transmits superframe SF1 and superframe SF2. Since the first normal base station 30, the first notice base station 31, the first fixed base station 32, and the first forced base station 33 are synchronized by the first line 3D, the start timing SFt1 of the super frame SF1 is each. The base stations match, and the start timing SFt2 of the super frame SF2 also matches at each base station.

The first normal base station 30 transmits the first operation signal and the first synchronization signal as the first normal signal at both the timings of the super frame SF1 and the super frame SF2. Therefore, the mobile station 21 can receive the first operation signal and the first synchronization signal without considering the difference between the super frame SF1 and the super frame SF2, and the communication frame is the super frame SF1 and the super frame SF2. There is no problem in operation by dividing into and.

The first advance notice base station 31 transmits the first advance notice signal 421 belonging to the first switching signal group 42 in the frame Fj1 in the super frame SF1, and belongs to the second switching signal group 41 in the frame Fj2 in the super frame SF2. 2 The forced signal 411 is transmitted. The first fixed base station 32 transmits the first fixed signal 422 belonging to the first switching signal group 42 in the frame Fj1 in the super frame SF1, and belongs to the second switching signal group 41 in the frame Fj2 in the super frame SF2. 2 The confirmation signal 412 is transmitted.

As described in the third embodiment, the first forced base station 33 needs to transmit the first operation dummy signal and the first synchronization signal except when the switching signal is transmitted in order to perform superframe synchronization. Therefore, in the super frame SF1, the first forced signal 423 belonging to the first switching signal group 42 is transmitted in the frame Fj1, and the first operation dummy signal and the first synchronization signal are transmitted at other timings. Further, in the super frame SF2, the second warning signal 413 belonging to the second switching signal group 41 is transmitted in the frame Fj2, and the first operation dummy signal and the first synchronization signal are transmitted at other timings.

As described above, in the wireless communication system 100D according to the present embodiment, the function of the second switching base station that transmits the second switching signal by the second wireless system in the third embodiment is the function of the first wireless system. By integrating into the first switching base station that transmits one switching signal, the number of switching base stations can be halved as compared with the third embodiment.

Further, by alternately transmitting the super frame SF1 and the super frame SF2, it is possible to realize a wireless communication system having the above effect without increasing the frequency even in a single wireless system.

In the present embodiment, the case where the functions of the three second switching base stations are integrated into the three first switching base stations to make the number of switching base stations three is described as an example, but it is not necessarily 3 It is not necessary to integrate all the second switching base stations with the first switching base station.

<Embodiment 5>
As described above, in the wireless communication system 100D according to the fourth embodiment, the first advance notice base station 31, the first fixed base station 32, and the first forced base station 33 use the same frequency f1 as the mobile station 21. When there is a mobile body 2 in an interference zone where communication is performed but the signal from the first advance notice base station 31 and the signal from the first fixed base station 32 interfere with each other, or the signal from the first fixed base station 32 and the first 1 When the mobile body 2 is in an interference zone where the signal from the forced base station 33 interferes, the mobile station 21 randomly receives four types of switching signals transmitted from two adjacent base stations. there is a possibility.

In this case, the mobile station 21 may not be able to correctly switch the wireless system according to the communication area. Therefore, in the wireless communication system according to the fifth embodiment, by limiting the transition of the state of the mobile station 21 in a short time such that the mobile body 2 passes through the interference zone, the wireless system is used even when there is an influence of interference. Can be switched normally. Since the configuration of the base station in the wireless communication system according to the fifth embodiment is the same as that of the wireless communication system 100D according to the fourth embodiment, detailed description thereof will be omitted.

FIG. 11 is a diagram for explaining the state transition of the mobile station 21 limited in the interference zones 1d and 1e of the switching base station according to the fifth embodiment of the present invention. In FIG. 11, the interference zone 1d indicates a zone where the signal from the first advance notice base station 31 and the signal from the first fixed base station 32 interfere with each other. Further, the interference zone 1e indicates a zone where the signal from the first fixed base station 32 and the signal from the first forced base station 33 interfere with each other.

As the state transition of the mobile station 21 in the interference zone 1d, the state transition t1 receives the first confirmation signal 421 and then the first confirmation signal 422, and the state transition t2 receives the first confirmation signal 422 and then the second compulsion. When the signal 411 is received, the state transition t3 receives the first warning signal 421 after receiving the second forced signal 411, and the state transition t4 receives the first warning signal 421 after receiving the second confirmation signal 412. It shows the case where.

Further, as the state transition of the mobile station 21 in the interference zone 1e, the state transition t5 receives the second confirmation signal 413 and then receives the second confirmation signal 412, and the state transition t6 receives the second confirmation signal 412 and then receives the second confirmation signal. 1 When the forced signal 423 is received, the state transition t7 receives the first forced signal 423 and then the second warning signal 413, and the state transition t8 receives the first confirmed signal 422 and then the second warning signal 413. Is received.

Of the state transitions t1 to t8, the state transition required for correctly switching the radio system of the mobile station 21 in the interference zone 1d is the state transition t1, and the radio system of the mobile station 21 is correctly turned off in the interference zone 1e. The state transition required for the change is the state transition t5, and the state transitions t2 to t4 and t6 to t8 are unnecessary state transitions.

Therefore, in the wireless communication system according to the present embodiment, when the mobile station 21 randomly receives four types of switching signals, an interference zone is provided so that the wireless system of the mobile station 21 does not switch to an unintended system. The state transitions t2 to t4 in 1d and the state transitions t6 to t8 in the interference zone 1e are limited.

First, the state transition in the interference zone 1d will be described. FIG. 12 is a diagram showing a state transition of the mobile station 21 in the interference zone 1d according to the fifth embodiment of the present invention. When the mobile body 2 exists in the interference zone 1d, the mobile station 21 receives the signals from the first advance notice base station 31 and the first fixed base station 32 existing on both sides of the interference zone 1d, so that the mobile station 21 receives the first advance notice signal 421. , The second forced signal 411, the first confirmed signal 422, and the second confirmed signal 412 may be randomly received.

At this time, the state transition occurs in the mobile station 21 when the mobile station 21 is in the first standby state ST1 and receives the first warning signal 421 to receive the first confirmation signal standby, as shown in FIG. A case where the mobile station 21 transitions to the state ST7, a case where the mobile station 21 is in the first confirmed signal standby state ST7 and receives the first confirmed signal 422 and transitions to the second standby state ST2, and a case where the mobile station 21 is in the second standby state. In the state ST2, when the second forced signal 411 is received and transitions to the first standby state ST1, the mobile station 21 is in the second confirmed signal standby state ST8, and the second forced signal 411 or the second confirmed state. There are four cases of receiving the signal 412 and transitioning to the first standby state ST1.

Further, the state transition t1 indicates a case of transitioning from the first standby state ST1 to the first confirmed signal standby state ST7 and then to the second standby state ST2. The state transition t2 indicates a case of transitioning from the first confirmed signal standby state ST7 to the second standby state ST2 and then to the first standby state ST1. The state transition t3 shows a case where the transition from the second standby state ST2 to the first standby state ST1 and then to the first confirmation signal standby state ST7. The state transition t4 shows a case where the transition from the second confirmed signal standby state ST8 to the first standby state ST1 and then to the first confirmed signal standby state ST7.

In the state transitions t1 to t4 in which the state transitions occur two times in a row in a short time when the moving body 2 moving between the first communication area 1a and the second communication area 1b exists in the interference zone 1d. Only the state transition t1 that transitions from the first standby state ST1 to the first confirmed signal standby state ST7 and then to the second standby state ST2 is required to correctly switch the wireless system.

Next, the state transition in the interference zone 1e will be described. FIG. 13 is a diagram showing a state transition of the mobile station 21 in the interference zone 1e according to the fifth embodiment of the present invention. When the mobile body 2 is present in the interference zone 1e, the mobile station 21 receives the signals from the first fixed base station 32 and the first forced base station 33 existing on both sides of the interference zone 1e, so that the mobile station 21 receives the first fixed signal. There is a possibility that four types of switching signals, 422, the second confirmation signal 412, the first forced signal 423, and the second warning signal 413, are randomly received.

At this time, the state transition occurs in the mobile station 21 when the mobile station 21 is in the second standby state ST2 and receives the second warning signal 413 to receive the second confirmation signal standby, as shown in FIG. A case where the mobile station 21 transitions to the state ST8, a case where the mobile station 21 is in the second confirmed signal standby state ST8 and receives the second confirmed signal 412 and transitions to the first standby state ST1, and a case where the mobile station 21 is in the first standby state. In the state ST1, when the first forced signal 423 is received and the transition to the second standby state ST2 occurs, and when the mobile station 21 is in the first confirmed signal standby state ST7, the first forced signal 423 or the first confirmed state There are four cases of receiving the signal 422 and transitioning to the second standby state ST2.

Further, the state transition t5 indicates a case of transitioning from the second standby state ST2 to the second confirmed signal standby state ST8 and then to the first standby state ST1. The state transition t6 indicates a case of transitioning from the second confirmed signal standby state ST8 to the first standby state ST1 and then to the second standby state ST2. The state transition t7 shows a case where the transition from the first standby state ST1 to the second standby state ST2 and then to the second confirmation signal standby state ST8. The state transition t8 indicates a case of transitioning from the first confirmed signal standby state ST7 to the second confirmed signal standby state ST2 and then to the second confirmed signal standby state ST8.

In the state transitions t5 to t8 in which the state transitions occur two times in a row in a short time when the moving body 2 moving between the first communication area 1a and the second communication area 1b exists in the interference zone 1e. Only the state transition t5, which transitions from the second standby state ST2 to the second confirmed signal standby state ST8 and then to the first standby state ST1, is required to correctly switch the wireless system.

Therefore, in the wireless communication system according to the present embodiment, the state transitions t1 to t8 in which the state transitions shown in FIGS. 12 and 13 occur in succession in a short time when the mobile body 2 exists in the interference zone 1d or 1e. Of these, the state transitions t2 to t4 and t6 to t8 other than the state transitions t1 and t5 that correctly switch the wireless system are restricted.

FIG. 14 is a flowchart showing an operation in which the mobile station 21 according to the fifth embodiment of the present invention switches the wireless system. As shown in FIG. 14, steps S15 and S16 are further provided as compared with the flowchart of FIG. 6 described in the second embodiment.

The process of step S15 is a wait process of x seconds. Here, x is a time parameter representing a short time such that the moving moving body 2 exists in the interference zones 1d and 1e. The process of step S15 is inserted between the process of step S13 and the process of step S2. The process of step S16 is a wait process of y seconds. Here, y is a time parameter representing a short time such that the moving moving body 2 exists in the interference zones 1d and 1e. The process of step S16 is inserted between the process of step S14 and the process of step S1.

The above-mentioned state transitions t2 to t4 and t6 to t8 to be restricted are state transitions in which the first state transitions of the two consecutive state transitions all include the switching of the wireless system, so the wait processing is switched to the wireless system. By inserting after processing, weight processing will be included during the initial state transition. In this case, since the mobile station 21 does not receive the next switching signal in a short time, it does not shift to the second state transition. That is, the state transitions t2 to t4 and t6 to t8 are transition-restricted.

On the other hand, since the state transitions t1 and t5 for correctly switching the wireless system are state transitions including the switching of the wireless system in the second state transition among the two continuous state transitions, the wait processing after the wireless system switching is in the state. It does not affect transitions t1 and t5. Therefore, as shown in FIG. 14, the state transition t1 is added by adding the x-second wait process in step S15 and the y-second wait process in step S16 after the switching operation of the radio system in step S13 and step S14, respectively. Of ~ t8, it is possible to limit only the state transitions t2 to t4 and t6 to t8 to be restricted.

As described above, in the wireless communication system according to the present embodiment, when the mobile body 2 exists in the interference zones 1d and 1e between the switching base stations, the mobile station 21 is randomly selected from the surrounding base stations. It is possible to suppress a phenomenon in which an unintended state transition occurs and the wireless system is not switched correctly when the signal of is received.

In the present invention, each embodiment can be freely combined, and each embodiment can be appropriately modified or omitted within the scope of the invention.

1 line, 1a 1st communication area, 1b 2nd communication area, 1c 3rd communication area, 1d, 1e interference zone, 2 mobile body, 3D 1st line, 5D 2nd line, 21 mobile station, 21a 1st mobile station , 21a1 1st operation signal processing unit, 21a2 1st synchronous signal processing unit, 21a3 1st switching signal processing unit, 21b 2nd mobile station, 21c switching unit, 21d judgment unit, 21e storage unit, 30 1st normal base station, 31 1st notice base station, 32 1st fixed base station, 33, 54 1st forced base station, 41 2nd switching signal group, 42 1st switching signal group, 50 2nd normal base station, 51 2nd notice base station , 52 2nd fixed base station, 53, 34 2nd forced base station, 411 2nd forced signal, 412 2nd fixed signal, 413 2nd notice signal, 421 1st notice signal, 422 1st fixed signal, 423 1st Forced signal, F1-FN, Fj1, Fj2 frame, SF, SF1, SF2 super frame.

Claims (6)

A wireless communication system that performs wireless communication between a mobile station on a mobile body and a plurality of base stations.
The plurality of base stations
In the first communication area, the first normal base station that transmits and receives normal signals to and from the mobile station by the first wireless system, and
In the second communication area, the mobile station and the second normal base station that transmit and receive the normal signal by a second radio system different from the first wireless system, and
Includes multiple switching base stations that transmit multiple switching signals, respectively.
When the mobile station receives the plurality of switching signals in a normal manner, the mobile station switches between the first radio system and the second radio system for transmitting and receiving the normal signal .
The plurality of switching base stations include a first forced base station and a second forced base station that transmit a first forced signal and a second forced signal as the switching signals, respectively.
The mobile station
When the first forced signal is received when the wireless system is the first wireless system, the wireless system is switched to the second wireless system.
When the second forced signal is received when the wireless system is the second wireless system, the wireless system is switched to the first wireless system.
The first forced base station is the first for the mobile station to perform the wireless communication in the second communication area by the first wireless system with the first forced signal. Send a sync signal and
The second forced base station has the second forced signal and the second for the mobile station to perform the wireless communication in the first communication area by the second wireless system. Send a sync signal and
The mobile station
In the second communication area, the first forced signal is received by using the first synchronous signal transmitted by the first forced base station.
Wherein the first communication area, that will receive the second force signal using the second synchronizing signal by the second forcing the base station transmits a radio communication system. A wireless communication system that performs wireless communication between a mobile station on a mobile body and a plurality of base stations.
The plurality of base stations
In the first communication area, the first normal base station that transmits and receives normal signals to and from the mobile station by the first wireless system, and
In the second communication area, the mobile station and the second normal base station that transmit and receive the normal signal by a second radio system different from the first wireless system, and
With multiple switching base stations that transmit multiple switching signals respectively
Including
When the mobile station receives the plurality of switching signals in a normal manner, the mobile station switches between the first radio system and the second radio system for transmitting and receiving the normal signal.
The plurality of switching base stations include a first forced base station and a second forced base station that transmit a first forced signal and a second forced signal as the switching signals, respectively.
The mobile station
When the first forced signal is received when the wireless system is the first wireless system, the wireless system is switched to the second wireless system.
When the second forced signal is received when the wireless system is the second wireless system, the wireless system is switched to the first wireless system.
The normal signal transmitted by the first normal base station includes a first synchronization signal for the mobile station to perform the radio communication in the first radio system.
The normal signal transmitted by the second normal base station includes a second synchronization signal for the mobile station to perform the radio communication in the second radio system.
The first forced base station transmits the first forced signal into the second communication area at a timing different from the normal signal by the second radio system.
The second forced base station transmits the second forced signal into the first communication area at a timing different from the normal signal by the first radio system.
The mobile station
In the second communication area, the first forced signal is received by using the second synchronization signal transmitted by the second normal base station.
A wireless communication system that receives the second forced signal using the first synchronization signal transmitted by the first normal base station in the first communication area. The wireless communication system according to claim 1 or 2 .
The plurality of switching base stations
A first notice base station and a first fixed base station that transmit a first notice signal and a first confirmation signal as the switching signals, respectively.
The switching signal includes a second warning base station and a second fixed base station that transmit a second warning signal and a second fixed signal, respectively.
The mobile station
When the first confirmation signal is received after receiving the first warning signal, the wireless system is switched from the first wireless system to the second wireless system.
A wireless communication system that switches the wireless system from the second wireless system to the first wireless system when the second definite signal is received after receiving the second warning signal. The wireless communication system according to any one of claims 1 to 3 .
The first wireless system and the second wireless system are wireless systems that perform the wireless communication in a unit frame composed of a plurality of frames.
A wireless communication system in which the normal signal and each of the plurality of switching signals transmitted by the same wireless system are assigned to different frames within the unit frame. The wireless communication system according to any one of claims 1 to 4 .
The switching base station that transmits the first switching signal, which is the switching signal for the mobile station to switch the wireless system from the first wireless system to the second wireless system, is set as the first switching base station.
The switching base station that transmits the second switching signal, which is the switching signal for the mobile station to switch the wireless system from the second wireless system to the first wireless system, is set as the second switching base station.
The first wireless system and the second wireless system are wireless systems that perform the wireless communication in a unit frame composed of a plurality of frames.
At least one of the plurality of first switching base stations and at least one of the plurality of second switching base stations are the same switching base stations.
The same base station is a wireless communication system in which the first switching signal and the second switching signal are alternately transmitted for each unit frame in the first wireless system or the second wireless system. The wireless communication system according to any one of claims 1 to 5 .
A wireless communication system in which the mobile station does not receive the plurality of switching signals within a predetermined time after performing the switching process of the wireless system.

Images