JP3987673B2 - Mobile communication system, mobile station and base station - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile communication system, and more particularly, to a mobile communication system that enables switching of transmission lines that can provide different communication speeds while performing communication.
[0002]
The present invention also relates to a mobile station and a base station used in such a mobile communication system.
[0003]
[Prior art]
Conventionally, in a mobile communication system using a mobile phone or the like, after a transmission path is set and communication between a mobile station and a base station is started, the set transmission path cannot be changed until the end of the communication. The communication procedure between the mobile device and the base station is performed as shown in FIG. 16, for example.
[0004]
In FIG. 16, the mobile station makes a call setup request to the base station by calling (101). The base station that has received the call setting request notifies the mobile station that the call setting request has been received (102), and issues a setting request for activation of a radio channel (transmission path) for connecting the call. (103). Thereafter, transmission / reception of a control signal for establishing a radio channel is performed between the mobile station and the base station (104).
[0005]
When the radio channel is established between the mobile station and the base station, the mobile station notifies the base station of completion of establishment of the radio channel (105). Thereafter, the base station calls the connection destination terminal (106) and responds to the connection destination terminal (107) from the base station to the mobile station through the established radio channel.
[0006]
When the mobile station receives the response of the connected terminal, the mobile station transmits the response confirmation to the base station (108). Thereafter, communication through the established radio channel is performed between the mobile station and the base station. (109). Communication between the mobile station and the base station is performed at a communication speed determined by a radio channel.
[0007]
The radio channel (transmission path) used for communication between the mobile station and the base station as described above is changed until the release signal is transmitted from the mobile station to the base station (110) when the call is completed. There is nothing. After the release signal is transmitted / received between the mobile station and the base station, the control signal is transmitted / received according to the release procedure of the transmission path between the mobile station and the base station, and the communication ends. (111 to 114).
[0008]
[Problems to be solved by the invention]
In the conventional mobile communication system as described above, the communication speed determined by the set transmission path is not changed from the start to the end of communication. For this reason, when the propagation situation between the mobile station and the base station deteriorates, such a countermeasure cannot be performed even though the disconnection due to the deterioration of the communication quality can be avoided by reducing the communication speed. In addition, when the propagation situation between the mobile station and the base station is improved, such measures cannot be taken even though the communication service quality can be improved by increasing the communication speed.
[0009]
Accordingly, a first problem of the present invention is to provide a mobile communication system that can maintain better communication between a mobile station and a base station.
[0010]
The second object of the present invention is to provide a mobile station used in such a mobile communication system.
[0011]
Furthermore, the third object of the present invention is to provide a base station used in such a mobile communication system.
[0012]
[Means for Solving the Problems]
In order to solve the first problem, the present invention provides a mobile communication system in which a wireless transmission path is set between a mobile station and a base station to communicate with each other. In the system, when communication is performed between the mobile station and the base station, communication quality determination means for determining the state of the communication quality, and the mobile station and the base according to the determination result in the communication quality determination means Transmission path switching control means for switching a wireless transmission path used for communication with a station to another wireless transmission path that provides a communication speed different from the communication speed provided by the wireless transmission path. The transmission path switching control means can transmit power even when the error rate is equal to or higher than a threshold in a mobile station that is communicating on a high-speed transmission path, and even when the error rate is lower than the threshold. Radio transmission used for communication between a mobile station and a base station in response to a request to change to a low-speed transmission path transmitted by a mobile station when an instruction for further increase from the maximum value is given for a predetermined time. If the base station that is switching the path and communicating on the high-speed transmission path receives a request for changing to a low-speed transmission path from the mobile station, the error rate is the threshold value when the uplink interference measurement value is greater than the threshold value. When it becomes larger, the wireless transmission line used for communication between the mobile station and the base station is switched according to the change setting instruction to the low-speed transmission line transmitted by the base station, and communication is performed on the low-speed transmission line. At the mobile station Is not controlled at the maximum value for a predetermined period of time, regardless of the transmission power control value, if the error rate becomes smaller than the threshold value, a request to change to the high-speed transmission line transmitted by the mobile station is made. When the wireless transmission path used for communication between the mobile station and the base station is switched accordingly, and the base station that is communicating on the low-speed transmission path receives a change request from the mobile station to the high-speed transmission path When the uplink interference amount measurement value is smaller than the threshold value, or when the error rate is smaller than the threshold value, between the mobile station and the base station according to the change setting instruction to the high-speed transmission path transmitted by the base station. The wireless transmission path used for communication Configured as follows.
[0013]
In such a mobile communication system, a wireless transmission path having a different communication speed is switched according to the communication quality while maintaining a communication state between the mobile station and the base station. As a result, when the propagation state (communication quality) between the mobile station and the base station deteriorates, it is possible to avoid disconnection of the wireless transmission path due to communication quality deterioration by switching to a wireless transmission path with a lower communication speed. . In spite of this, such a countermeasure cannot be performed. Also, when the propagation state (communication quality) between the mobile station and the base station is improved, the quality of communication service can be improved by switching to a wireless transmission path with a higher communication speed.
[0014]
The communication quality determination means can be provided in the mobile station as described in claim 2 or can be provided in the base station as described in claim 3.
[0015]
The communication quality determination means is configured to determine the state of communication quality based on an error rate of a signal transmitted and received in communication between a mobile station and a base station, for example, as described in claim 4 can do. In this case, when the error rate increases, the wireless transmission path can be switched to a lower speed, and when the error rate decreases, the wireless transmission path can be switched to a higher speed.
[0016]
Further, as described in claim 5, the communication quality determination means can be configured to determine the state of communication quality based on the uplink interference amount. In this case, when the uplink interference amount increases, the wireless transmission path is switched to a lower speed, and when the uplink interference amount decreases, the wireless transmission path is switched to a higher speed.
[0017]
There is a mobile communication system in which an instruction to increase transmission power is given from a base station to a mobile station when reception quality at the base station is poor. From the viewpoint that the communication state can be easily determined in such a mobile communication system, the present invention provides the mobile communication system as described in claim 6, wherein the communication quality determination means is a mobile station. In the state where the transmission power is controlled at the maximum value, whether or not the base station is instructed to increase the transmission power continuously for a predetermined time, the communication quality state in the communication between the mobile station and the base station is determined. It can comprise so that it may have the 1st transmission power control determination means obtained as a determination result.
[0018]
From the same point of view, according to the present invention, as described in claim 7, in each of the mobile communication systems, the communication quality determination unit continues the transmission power to a value other than the maximum value for a predetermined time. The second transmission power control determining means for obtaining the determination result of the communication quality state in the communication between the mobile station and the base station.
Mobile communication system.
[0019]
As described above, from the viewpoint that communication can be performed at an appropriate communication speed according to communication quality, the present invention provides the transmission path switching control means in each mobile communication system as described in claim 8. Is a wireless transmission path used for communication between the mobile station and the base station when the communication quality determination means obtains a determination result that the communication quality has deteriorated from a predetermined standard. And a speed reduction control unit that switches to another wireless transmission path that provides a communication speed lower than the communication speed provided by the transmission path.
[0020]
Further, from the same viewpoint, as described in claim 9, according to the present invention, in each of the mobile communication systems, the transmission path switching control means has the communication quality judging means to improve the communication quality from a predetermined standard. When a determination result is obtained indicating that the mobile station and the base station are in a different state, another wireless that provides a communication speed higher than the communication speed provided by the wireless transmission path is used for communication between the mobile station and the base station. It can be configured to have an acceleration control means for switching to a transmission line.
[0021]
From the viewpoint that communication after switching can be performed reliably, the present invention provides, in each of the mobile communication systems described above, the transmission path switching control means is a mobile station. Provided in , Having a switchability determination means for determining whether or not communication with the base station is possible on the wireless transmission path after switching, and communication is possible on the wireless transmission path after switching by the switchability determination means The wireless transmission path can be switched when it is determined that it is possible.
[0022]
For example, as described in claim 11, the switching possibility determination unit can perform communication on the wireless transmission path after switching based on whether or not signal synchronization can be established on the wireless transmission path after switching. It can be configured to determine whether or not.
[0023]
In order to solve the second problem, the present invention provides a mobile station that establishes a wireless transmission path with a base station and communicates with the base station, as described in claim 12. Communication quality determining means for determining the state of the communication quality when communication is being performed, and a wireless transmission path used for communication with the base station according to the determination result of the communication quality determining means Transmission path change request means for requesting the base station to switch to another communication transmission path that provides a communication speed different from the communication speed provided by the wireless transmission path, The transmission path change request means is configured to transmit power from the maximum value even when the error rate is equal to or greater than a threshold value and when the error rate is smaller than the threshold value when performing communication on a high-speed transmission path. Further, when an increase instruction is continuously made for a predetermined time, a request for changing to a low-speed transmission path is transmitted to the base station, and when communication is performed on the low-speed transmission path, the transmission power is the maximum value. When the uncontrolled state continues for a predetermined time, regardless of the control value of transmission power, when the error rate becomes smaller than the threshold, a change request to the high-speed transmission path is transmitted to the base station, The radio transmission path used for communication between the mobile station and the base station is switched in accordance with a request from the transmission path change request means to the base station.
[0024]
Furthermore, in order to solve the third problem described above, the present invention provides a base station in which a wireless transmission path is set up with a mobile station to communicate with each other as described in claim 21. Communication quality determination means for determining the communication quality state when communication is performed with the mobile station, and used for communication between the mobile station according to the determination result of the communication quality determination means A transmission path change setting instruction means for instructing the mobile station to switch the wireless transmission path to another wireless transmission path that provides a communication speed different from the communication speed provided by the wireless transmission path; When the transmission path change setting instruction means receives a change request from the mobile station to the low-speed transmission path when performing communication on the high-speed transmission path, when the uplink interference amount measurement value is larger than the threshold value, When the error rate is greater than the threshold, a change setting instruction to the low-speed transmission path is sent to the mobile station, and when communication is performed on the low-speed transmission path, a change request from the mobile station to the high-speed transmission path is issued. When received, when the uplink interference measurement value is smaller than the threshold, when the error rate is smaller than the threshold, a change setting instruction to the high-speed transmission path is transmitted to the mobile station, A radio transmission path used for communication between the mobile station and the base station is switched in accordance with an instruction from the transmission path change setting instruction means to the mobile station.
[0025]
Furthermore, in order to solve the third problem, the present invention provides a base for communicating with each other by setting a wireless transmission path with a mobile station, as described in claim 22. The station receives a request from the mobile station to switch the wireless transmission path used for communication with the mobile station to another wireless transmission path that provides a communication speed different from the communication speed provided by the wireless transmission path. A transmission path change setting instruction means for instructing the mobile station to switch the wireless transmission path, When the transmission path change setting instruction means receives a change request from the mobile station to the low-speed transmission path when performing communication on the high-speed transmission path, when the uplink interference amount measurement value is larger than the threshold value, When the error rate is greater than the threshold, a change setting instruction to the low-speed transmission path is sent to the mobile station, and when communication is performed on the low-speed transmission path, a change request from the mobile station to the high-speed transmission path is issued. When received, when the uplink interference measurement value is smaller than the threshold, when the error rate is smaller than the threshold, a change setting instruction to the high-speed transmission path is transmitted to the mobile station, A radio transmission path used for communication between the mobile station and the base station is switched in accordance with an instruction from the transmission path change setting instruction means to the mobile station.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0027]
The basic configuration of a mobile communication system according to an embodiment of the present invention is as shown in FIG.
[0028]
In FIG. 1, a mobile station (for example, a mobile phone) 10 located in the service area Es (wireless zone) of the base station 20 performs wireless communication with the base station 20. The base station 20 is connected to a predetermined network via the switching center 30, and the mobile station 10 communicates (calls and data communication) with the counterpart terminal via the base station 20, the switching center 30 and the predetermined network. .
[0029]
The mobile station 10 is configured as shown in FIG. 2, for example. FIG. 2 conceptually shows portions of the mobile station 10 related to the present invention, and other portions are omitted.
[0030]
In FIG. 2, the mobile station 10 includes a control unit 11 and a radio unit 12. The wireless unit 12 includes a transmission / reception unit 121 and a wireless measurement unit 122. The transmission / reception unit 121 transmits and receives signals to and from the base station 20 by wireless communication. The wireless measurement unit 122 measures the transmission path state based on the received signal from the transmission / reception unit 121. Specifically, the level of the received signal is measured, and an error rate (FER: Frame Error Rate) as described later is measured.
[0031]
The control unit 11 includes a timer control unit 111 and a determination unit 112. The determination unit 112 determines whether to switch the connected transmission line between high speed and low speed based on the transmission line state measured by the wireless measurement unit 122. The determination result of the transmission line switching obtained by the determination unit 112 is sent to the transmission / reception unit 121, and the transmission / reception unit 121 transmits a control signal (transmission path change request) based on the determination result. The timer control unit 111 provides timer information used for determination processing performed by the determination unit 112.
[0032]
On the other hand, the base station 20 is configured as shown in FIG. 3, for example. FIG. 3 conceptually shows portions of the base station related to the present invention, and other portions are omitted.
[0033]
In FIG. 3, the base station 20 includes a control unit 21 and a radio unit 22. The wireless unit 22 includes a transmission / reception unit 221 and a wireless measurement unit 222. The transmission / reception unit 221 transmits / receives signals to / from the mobile station 10 described above by wireless communication. The radio measurement unit 222 measures the transmission path state based on the downlink signal from the mobile station 10 received by the transmission / reception unit 221. Specifically, measurement of the received signal level, measurement of uplink interference (UI), measurement of error rate (FER), and the like as described later are performed.
[0034]
The control unit 21 has a determination unit 211. This determination unit 211 performs high-speed transmission on the connected transmission path based on the transmission path state measured by the wireless measurement section 222 and the control signal related to the transmission path change request from the mobile station 10 received by the transmission / reception section 221. Whether to switch to low speed or low speed is determined. The transmission / reception unit 121 transmits a control signal (transmission path change setting) based on the determination result.
[0035]
In the process of performing wireless communication between the mobile station 10 and the base station 20 configured as described above, the mobile station 10 (mainly the determination unit 112 in the control unit 11) follows, for example, the procedure shown in FIG. The processing is done.
[0036]
In FIG. 4, for example, a downlink transmission path measured by the wireless measurement unit 122 in the process of performing communication (701) between the mobile station 10 and the base station 20 in a state where a high-speed transmission path is set (701). It is determined whether or not the error rate FER is smaller than a preset threshold FER_Low (702). When the error rate FER is smaller than the threshold value FER_Low (YES in 702), it is determined whether the transmission power controlled by the transmission / reception unit 121 is the maximum value (MAX) (703). When the transmission power is not controlled to the maximum value (MAX) (NO in 703), the communication on the high-speed transmission line is performed while the error rate FER determination (702) and the transmission power determination (703) are repeatedly performed. (701) is continued.
[0037]
In the process of performing communication on this high-speed transmission line, if the transmission line condition deteriorates and the error rate FER becomes equal to or greater than the threshold value FER_Low (NO in 702), the determination unit 112 requests the change to the low-speed transmission line. A transmission instruction is output to the transmission / reception unit 121 (709). As a result, the transmission / reception unit 121 transmits a request for changing to the low-speed transmission path to the base station 20. Then, the mobile station 10 maintains the communication state (710, 711).
[0038]
On the other hand, when the transmission rate is controlled to the maximum value (MAX) while the error rate FER is smaller than the threshold value FER_Low (YES in 703), the determination unit 112 outputs a timer start command to the timer control unit 111. (704). Thereafter, it is determined again whether or not the error rate FER is smaller than the threshold FER_Low (705), and whether or not there is an instruction to increase the transmission power from the base station 10 due to deterioration of the reception state in the base station 10 (706). In a state where there is no instruction to increase the transmission power from the base station 10 (NO in 706), a timer stop command is output to the timer control unit 111 (707), and the processes in the above steps (702 to 707) are repeated. Communication on the high-speed transmission path is maintained.
[0039]
In this state, when the error rate FER is equal to or higher than the threshold FER_Low (NO in 705), the determination unit 112 transmits a transmission request for a change request to the low-speed transmission path, as in the case described above (in the case of 702). (709), and the transmission / reception unit 121 transmits a request for changing to the low-speed transmission path to the base station 10 based on the instruction. Even if the error rate FER is smaller than the threshold FER_Low (YES in 705), if the base station 10 gives an instruction to increase the transmission power (YES in 708), the transmission power is already at the maximum value (MAX). ) And the reception state at the base station 10 cannot be improved. Therefore, it is determined whether the timer has timed out (expired) (708), and the determination processes (705, 706, 708). ) Is executed repeatedly.
[0040]
In this state, when the determination unit 112 receives a timer timeout report from the timer control unit 111 (YES in 708), the reception state at the base station 10 cannot be improved by communication on the high-speed transmission path as described above. Therefore, a transmission request for a change request to the low-speed transmission path is output to the transmission / reception unit 121 (709), and a change request to the low-speed transmission path is transmitted from the transmission / reception unit 121 to the base station 10 based on the instruction. Then, the timer stop process (710) is performed, and the mobile station 10 maintains the communication state (710, 711).
[0041]
As described above, in the mobile station 10 that communicates with the base station 20 through the high-speed transmission path, when the error rate FER is equal to or higher than the threshold value FER_Low (NO in 702 and NO in 705), the error rate FER is the threshold value. Even if the transmission power is instructed to increase further from the maximum value (MAX) for a predetermined time (YES at 706, YES at 708) even in a state smaller than FER_Low, the low-speed transmission path is triggered by those conditions. The change request to is transmitted to the base station 10.
[0042]
The base station 20 that communicates with the mobile station 10 that performs the above-described processing through the high-speed transmission path performs processing according to the procedure illustrated in FIG. 5, for example.
[0043]
In FIG. 5, the determination unit 211 determines whether or not a transmission path change request has been made from the mobile station 10 while performing communication with the mobile station 10 via a high-speed transmission path (801, 805). Then, determination is made as to whether or not the uplink interference amount measurement value UI obtained by the wireless measurement unit 222 has become larger than a predetermined threshold ThUI_Low (803), and the error rate FER obtained by the wireless measurement unit 222 is predetermined. It is repeatedly determined whether or not the threshold value FER_Low has been exceeded. In the process, when the change request to the low-speed transmission path is received from the mobile station 10 as described above (YES in 802), the determination unit 211 sends the transmission request for the change setting instruction to the low-speed transmission path. (806). Then, processing related to the transmission path change is executed (807).
[0044]
In addition, when the uplink interference measurement value UI is larger than the threshold ThUI_Low (YES in 803), or when the error rate FER is larger than the threshold FER_Low (YES in 804), the determination unit 211 is similar to the above. Outputs a transmission request for a change setting instruction to the low-speed transmission path to the transmission / reception unit 221 (806), and processing related to the transmission path change is executed (807).
[0045]
As described above, when the base station 20 that communicates with the mobile station 10 through the high-speed transmission path receives a change request from the mobile station 10 to the low-speed transmission path (YES in 802), the uplink interference amount measurement value UI is If the error rate FER is greater than the threshold FER_Low (YES in 803) when the threshold ThUI_Low is exceeded (YES in 803), a change setting instruction for a low-speed transmission path is transmitted to the mobile station 10 using those conditions as a trigger. To do.
[0046]
In the process in which the mobile station 10 and the base station 20 communicate with each other through the high-speed transmission path by the processing in the mobile station 10 and the base station 20 described above, the mobile station 10 is triggered by the above various conditions as a trigger to the low-speed transmission path. A change request is transmitted to the base station 20, and the base station 20 transmits to the mobile station 10 a change setting instruction for a low-speed transmission path triggered by the various conditions described above.
[0047]
On the other hand, the mobile station 10 that communicates with the base station 10 through the low-speed transmission path performs processing according to the procedure shown in FIG. 6, for example.
[0048]
In FIG. 6, an error in the downlink transmission path measured by the wireless measurement unit 122 in the process of performing communication in a state where a low-speed transmission path is set between the mobile station 10 and the base station 20 (1101). It is determined whether or not the rate FER is smaller than a preset threshold FER_high (1102). If the error rate FER is not smaller than the threshold FER_high (NO in 1102), it is determined whether the transmission power controlled by the transmission / reception unit 121 is the maximum value (MAX) (1103). In a state where the transmission power is controlled to the maximum value (MAX) (YES in 1103), the communication on the low-speed transmission path is performed while the error rate FER determination (1102) and the transmission power determination (1103) are repeatedly executed. (1101) is continued.
[0049]
Even if the error rate FER is equal to or higher than the threshold value FER_high (NO in 1120), the transmission power is not controlled to the maximum value (MAX), and it is possible to compensate for the communication quality deterioration in the high-speed communication service. If NO (1103: NO), the determination unit 112 outputs a timer start command to the timer control unit 111 (1104). Thereafter, it is determined again whether or not the error rate FER is smaller than the threshold value FER_high (705) and whether or not the transmission power is controlled to the maximum value (MAX) (1106). If the transmission power is in a state controlled to the maximum value (MAX) (1106), the determination unit 112 instructs the timer control unit 111 to stop the timer (1107) and performs communication on the low-speed transmission path. (1101), the above determination processing (1102, 1103) is repeatedly executed.
[0050]
On the other hand, if the state where the transmission power is not controlled at the maximum value (MAX) is maintained (NO in 1106), it is further determined whether or not the timer has timed out (expired) (1108). At the same time, the above determination processes (1105, 1106) are repeatedly executed.
[0051]
In this state, when the error rate FER is smaller than the threshold FER_high (YES in 1105), the determination unit 112 outputs a transmission request for a change request to the high-speed transmission path to the transmission / reception unit 121 (1109), and based on the instruction A request for changing to a high-speed transmission path is transmitted from the transceiver 121 to the base station 20. Then, the timer is stopped (1110), and the mobile station 10 maintains the communication state (1110).
[0052]
In addition, it is determined whether or not the error rate FER is smaller than the threshold FER_high (1105), whether or not the transmission power is controlled to the maximum value (MAX) (1106), and the timer has timed out (expired). If the timer times out during the process of repeatedly determining whether or not (1108) (YES in 1108), it can be determined that the reception state at the base station 20 is improved as described above. The unit 112 outputs a transmission request for a change request to the high-speed transmission path to the transmission / reception unit 121 (1109), and the transmission / reception unit 121 transmits a change request to the high-speed transmission path to the base station 20 based on the instruction. The Then, the timer is stopped (1110), and the mobile station 10 maintains the communication state (1111).
[0053]
Further, as described above, while the transmission power is controlled at the maximum value (MAX) (YES in 1103), the error rate FER is determined in the process of determining the repetition error rate FER (1102). Is smaller than the threshold value FER_high, it is determined that the transmission path state is good, and the determination unit 112 outputs a transmission request for a change request to the high-speed transmission path to the transmission / reception unit 122 (1109). A request for changing to a high-speed transmission path is transmitted from 121 to the base station 20.
[0054]
As described above, in the mobile station 10 that communicates with the base station 20 through the low-speed transmission path, the transmission power is not controlled at the maximum value (MAX) (NO in 1103, NO in 1106) for a predetermined time. In the case (YES in 1108), regardless of the transmission power control value (YES in 1103 or NO in 1106), if the error rate FER is smaller than the threshold FER_high (YES in 1102 and YES in 1105), A request for changing to a high-speed transmission path is transmitted to the base station 10 using the above condition as a trigger.
[0055]
The base station 20 that communicates with the mobile station 10 that performs the above-described processing through the low-speed transmission path performs processing according to the procedure illustrated in FIG. 7, for example.
[0056]
In FIG. 7, the determination unit 211 determines whether or not a transmission path change request has been made from the mobile station 10 while communicating with the mobile station 10 via a low-speed transmission path (1201, 1205). Then, determination is made as to whether or not the uplink interference amount measurement value UI obtained by the radio measurement unit 222 has become smaller than a predetermined threshold ThUI_high (1203), and the error rate FER obtained by the radio measurement unit 222 is predetermined. The determination as to whether or not the threshold value FER_high has been reached is repeatedly performed. In the process, when a request for changing to a high-speed transmission path is received from the mobile station 10 as described above (YES in 1202), the determination unit 211 uses a radio resource (for example, a radio transmission path) for setting the high-speed transmission path. It is determined whether or not there is (capacity) (1206). If there is such a radio resource (YES in 1206), a transmission request for a change setting instruction for a high-speed transmission path is output to the transmission / reception unit 221 (1207). Then, processing related to transmission path change is executed (1208). On the other hand, if there are many mobile stations 10 in communication within the service area Es of the base station 20 and there is no such radio resource, the communication state on the low-speed transmission path is maintained (1205).
[0057]
Similarly, when the uplink interference measurement value UI is smaller than the threshold ThUI_high (YES in 1203) or the error rate FER is smaller than the threshold FER_high (YES in 1204), the determination unit 211 similarly Then, the presence / absence of a radio resource for setting a high-speed transmission path is determined (1206). If there is such a radio resource, a transmission request for a change setting instruction to the high-speed transmission path is output to the transmission / reception unit 221 (1207). ), Processing related to the transmission path change is executed (807).
[0058]
As described above, when the base station 20 that communicates with the mobile station 10 through the high-speed transmission path receives a change request from the mobile station 10 to the high-speed transmission path (YES in 1202), the uplink interference amount measurement value UI is When the error rate FER is smaller than the threshold value FER_high (YES in 1203) when the threshold value ThUI_high is smaller (YES at 1203), the mobile station 10 is sent a change setting instruction to the high-speed transmission path using those conditions as a trigger. To do.
[0059]
In the process in which the mobile station 10 and the base station 20 communicate with each other through the low-speed transmission path by the processing in the mobile station 10 and the base station 20 described above, the mobile station 10 is switched to the high-speed transmission path by using the various conditions as a trigger. A change request is transmitted to the base station 20, and the base station 20 transmits a change setting instruction to the high-speed transmission path to the mobile station 10 triggered by the above various conditions.
[0060]
Furthermore, as described above, the mobile station 10 transmits to the base station 20 a request for changing the transmission path used for communication with the base station 20 according to the state of the transmission path (error rate FER). The mobile station 10 further performs processing for transmission path change control based on the request, for example, according to the procedure shown in FIG.
[0061]
In FIG. 8, in the state (1301) in which communication is performed with the base station 20 through either the low-speed transmission line or the high-speed transmission line, the determination unit 112 satisfies the transmission line change trigger condition as described above. (1302 in FIG. 4 or 1102 to 1108 in FIG. 6) is determined (1302). When the transmission path change / change trigger condition is satisfied (YES in 1302, NO in 702 in FIG. 4, NO in 705, YES in 708, YES in 1102 in FIG. 5, YES in 1105) As described above, a transmission path change request is transmitted from the mobile station 10 to the base station 20 (1303, corresponding to 709 in FIG. 4 or 1109 in FIG. 5).
[0062]
Thus, when the mobile station 10 requests the base station 20 to change to the high-speed transmission path or to change to the low-speed transmission path, the determination unit 112 of the mobile station 10 A timer start request is made (1304). In response to this request, the timer control unit 111 starts the operation of the timer. In this state, the determination unit 112 determines whether or not the timer has timed out (expired) (1305) and whether or not the transmission path change setting signal is received from the base station 20 (1306). . If the transmission path change setting signal is not received from the base station 20 before the timer times out (NO in 1306), the determination unit 112 stops the timer (1310) and then maintains the current communication state. (1301), the above processing (1302-1306) is repeatedly executed.
[0063]
On the other hand, if the transmission path change setting signal (transmitted at 806 in FIG. 5 or 1207 in FIG. 7) is received from the base station 20 before the timer times out (YES in 1306), the timer is stopped (1307). Then, it is determined whether or not synchronization can be established in the changed transmission path (1308). When synchronization is established in the changed transmission path (successful in 1308), the determination unit 112 outputs a transmission path change setting response signal transmission instruction to the transmission / reception section 121 (1309), and transmits / receives according to the instruction. A transmission path change setting response signal is transmitted from unit 121 to base station 20. On the other hand, if synchronization cannot be established on the changed transmission line (failed in 1308), the current transmission line recovery process is performed (1311), and the communication state on the transmission line is maintained.
[0064]
In the base station 20 that communicates with the mobile station 10 that performs the above-described processing, for example, the process is performed according to the procedure shown in FIG.
[0065]
In FIG. 9, in the state (1401) in which the mobile station 10 communicates with either the low speed transmission path or the high speed transmission path, the determination unit 211 changes the transmission path from the mobile station 10 as described above. Determination of whether or not the request signal has been received (processing in 802 in FIG. 5 or processing in 1202 in FIG. 7) and determination of whether or not the conditions of the transmission path change setting trigger are satisfied (in FIG. 5) The processing at 803 and 804 or the processing at 1203 and 1204 in FIG. 7) is repeatedly executed (1402, 1403). As a result of the determination process, when a transmission path change request is received from the mobile station 10 (YES in 1402) or the transmission path change setting trigger condition is satisfied (YES in 1403), as described above. A transmission path change setting signal is transmitted from the base station 20 to the mobile station 10 (corresponding to 1404, 806 in FIG. 5 or 1206, 1207 in FIG. 7).
[0066]
When the transmission path change setting signal is transmitted from the base station 20 to the mobile station 10 in this way, the determination unit 211 of the base station 20 starts a timer operation (1405). In this state, the determination unit 211 determines whether or not synchronization can be established on the changed transmission path (1406). When synchronization can be established on the transmission path after the change, the determination unit 211 further determines whether or not a transmission path change setting response signal (transmitted in 1309 in FIG. 8) has been received from the mobile station 10. (1407) and determination (1408) of whether or not the timer has timed out (expired) is repeatedly executed. In the process, when a transmission path change setting response signal is received from the mobile station 10 (YES in 1407), the timer is stopped (1410), and communication is continued on the changed transmission path (1411).
[0067]
On the other hand, if the timer has timed out (NO in 1408) without receiving the transmission path change setting response signal from the mobile station 10 (NO in 1407), the current transmission path recovery process that is not changed is performed. (1409). If the transmission path change setting signal is transmitted from the base station 20 to the mobile station 10 (1404), and synchronization cannot be established in the changed transmission path (NO in 1406), the determination unit 211 determines that the timer Similarly to the time-out, the current transmission path recovery process that is not changed is performed (1409).
[0068]
As described above, communication is continued between the mobile station 10 and the base station 20 on either the high-speed transmission path or the low-speed transmission path, and depending on the transmission status between the mobile station 10 and the base station 20 Switching to a high-speed transmission path or a low-speed transmission path is performed.
[0069]
As a result of the mobile station 10 and the base station 20 communicating with each other performing the processing as described above, the transmission path is changed between the mobile station 10 and the base station 20 according to the procedure shown in FIGS. Is done.
[0070]
FIG. 10 shows a procedure for changing from a high-speed transmission path to a low-speed transmission path by a trigger from the mobile station 10. In FIG. 10, in the process in which the mobile station 10 and the base station 20 communicate with each other through a high-speed transmission path (201), it is difficult for the mobile station 10 to maintain communication on the high-speed transmission path (for example, error rate). If it is determined that the FER is equal to or greater than the threshold FER_Low (203), a request for changing to a low-speed transmission path (notification of difficulty in maintaining quality) is transmitted from the mobile station 10 to the base station 20 (203). The base station 20 that has received the request for changing to the low-speed transmission path transmits a transmission path change setting instruction serving as a message for changing to the low-speed transmission path to the mobile station 10 (204). Receiving this instruction, the mobile station 10 confirms the establishment of synchronization in the instructed low-speed transmission path and changes to the low-speed transmission path (205).
[0071]
After the transmission path is changed in this way, the mobile station 10 transmits a transmission path change setting response signal that becomes a transmission path change completion notification to the base station 20 (206). Thereafter, communication on the newly set low-speed transmission path is started between the mobile station 10 and the base station 20 (207).
[0072]
FIG. 11 shows a procedure for changing from a low-speed transmission path to a high-speed transmission path by a trigger from the mobile station 10. In FIG. 11, in the process in which the mobile station 10 and the base station 20 are communicating on the low-speed transmission path (401), the mobile station 10 can use the high-speed transmission path (for example, the error rate FER is If it is determined that it is smaller than the threshold FER_high (402), a change request to the high-speed transmission path (notification of high-speed communication possible) is transmitted from the mobile station 10 to the base station 20 (403). The base station 20 that has received the request for changing to the high-speed transmission path confirms whether or not the communication state in the service area is in a state where a high-speed transmission path can be set for the mobile station 10, and changes to the high-speed transmission path. A transmission path change setting instruction serving as a message for transmission is transmitted to the mobile station 10 (404). Receiving this instruction, the mobile station 10 confirms establishment of synchronization in the instructed high-speed transmission line and changes the high-speed transmission line (405).
[0073]
After the transmission path is changed in this way, the mobile station 10 transmits a transmission path change setting response signal to be a transmission path change completion notification to the base station 20 (406). Thereafter, communication on the newly set high-speed transmission path is started between the mobile station 10 and the base station 20 (407).
[0074]
FIG. 12 shows a procedure for changing from a high-speed transmission path to a low-speed transmission path by a trigger from the base station 20. In FIG. 12, in the process in which the mobile station 10 and the base station 20 are communicating on the high-speed transmission path (301), the base station 20 has sufficient quality to maintain the communication on the high-speed transmission path. If it is determined that it cannot be secured (uplink interference amount UI is greater than threshold ThUI_low, error rate FER is greater than threshold FER_Low, etc.) (302), a transmission path that becomes a message for changing the transmission path to a low-speed transmission path A change setting instruction is transmitted from the base station 20 to the mobile station 10 (303). Receiving this instruction, the mobile station 10 confirms the establishment of synchronization in the instructed low-speed transmission path and changes the low-speed transmission path (304).
[0075]
After the transmission path is changed in this way, the mobile station 10 transmits a transmission path change setting response signal to be a transmission path change completion notification to the base station 20 (405). Thereafter, communication on the newly set low-speed transmission path is started between the mobile station 10 and the base station 20 (406).
[0076]
FIG. 13 shows a procedure for changing from a low-speed transmission path to a high-speed transmission path by a trigger from the base station 20. In FIG. 13, in the process in which the mobile station 10 and the base station 20 are communicating on the low speed transmission path (501), the reception reception quality in the communication on the low speed transmission path is improved, and the communication on the high speed transmission path is performed. If it is determined that sufficient quality can be ensured to maintain (uplink interference amount UI is smaller than threshold ThUI_high, error rate FER is smaller than threshold FER_high) (502), the transmission line is changed to a high-speed transmission line. A transmission path change setting instruction serving as a message for transmission is transmitted from the base station 20 to the mobile station 10 (503). The mobile station 10 that has received this instruction performs confirmation of establishment of synchronization in the instructed high-speed transmission path and changes to the high-speed transmission path (504).
[0077]
After the transmission path is changed in this way, the mobile station 10 transmits a transmission path change setting response signal to be a transmission path change completion notification to the base station 20 (505). Thereafter, communication on the newly set high-speed transmission path is started between the mobile station 10 and the base station 20.
[0078]
An example in which the transmission path used for communication between the mobile station 10 and the base station 20 as described above is changed is shown in FIG. In this case, in the service area Es of the base station 20, communication in the high-speed transmission path is ensured between the mobile station 10 and the base station 20 in the region Es1 that is relatively close to the base station 20. Further, in the area Es2 that is the periphery of the service area Es, communication on the low-speed transmission path is guaranteed between the mobile station 10 and the base station 20. When the mobile station 10 moves from the area Es1 to the area Es2 while communicating with the base station 20, the transmission path used for communication between the mobile station 10 and the base station 20 is high-speed at the boundary. The transmission line is changed to a low-speed transmission line. Conversely, when the mobile station 10 moves from the area Es2 to the area Es1, the transmission path used for communication between the mobile station 10 and the base station 20 changes from the low-speed transmission path to the high-speed transmission path at the boundary. Changed to
[0079]
Another example in which a transmission path used for communication between the mobile station 10 and the base station 20 is changed is shown in FIG. In this case, the number of mobile stations residing in the service area Es1 of the base station 20 (1) is different from the number of mobile stations residing in the service area Es2 of the base station 20 (2), and is allowed in the service area Es1. The maximum communication speed is greater than the maximum communication speed allowed in the service area Es2. In such a situation, when the mobile station 10 moves from the service area Es1 to the service area Es2 (handover), a high-speed transmission path is used when the mobile station 10 communicates with the base station 20 (1). When 10 communicates with the base station 20 (2), the transmission path used is changed to a low-speed transmission path. Conversely, when the mobile station 10 moves from the service area Es2 to the service area Es1, the low-speed transmission path is used when the mobile station 10 communicates with the base station 20 (2), and the mobile station 10 receives the base station 20 ( When communicating with 1), the transmission path used is changed to a high-speed transmission path.
[0080]
In the mobile communication system as described above, when the transmission path state deteriorates while the mobile station 10 and the base station 20 continue communication, the transmission path to be used is changed from the high-speed transmission path to the low-speed transmission path. . Conversely, when the transmission path state is improved, the transmission path used can be changed from the low-speed transmission path to the high-speed transmission path.
[0081]
In the above example, the processing in steps 702, 705, 705 and 708 shown in FIG. 4, the processing in steps 803 and 804 in FIG. 5, the processing in steps 1102, 1105, 1106 and 1108 shown in FIG. The processing in steps 1203 and 1204 shown corresponds to the communication quality determination means, and the processing shown in FIGS. 8 and 9 corresponds to the transmission path switching control means. The processing in step 1308 shown in FIG. 8 and the processing in step 1406 shown in FIG. 9 correspond to the switchability determination unit.
[0082]
【The invention's effect】
As described above, according to the mobile communication system of the present invention described in claims 1 to 11, communication is performed according to the communication quality while maintaining the communication state between the mobile station and the base station. Since switching of wireless transmission paths with different speeds is performed, communication in a better state can be maintained between the mobile station and the base station. According to the present invention of claims 12 to 21, a mobile station used in the mobile communication system as described above can be provided. Furthermore, according to the present invention of claims 22 to 29, a base station used in the mobile communication system as described above can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration example of a mobile communication system according to an embodiment of the present invention.
2 is a block diagram conceptually showing a configuration example of a main part of a mobile station in the mobile communication system shown in FIG.
3 is a block diagram conceptually showing a configuration example of a main part of a base station in the mobile communication system shown in FIG.
FIG. 4 is a flowchart showing a processing example for switching from a high-speed transmission path to a low-speed transmission path in a mobile station.
FIG. 5 is a flowchart illustrating a processing example for switching from a high-speed transmission path to a low-speed transmission path in a base station.
FIG. 6 is a flowchart illustrating a processing example for switching from a low-speed transmission path to a high-speed transmission path in a mobile station.
FIG. 7 is a flowchart illustrating a processing example for switching from a low-speed transmission path to a high-speed transmission path in a base station.
FIG. 8 is a flowchart illustrating a processing example related to transmission path switching control in a mobile station.
FIG. 9 is a flowchart illustrating a processing example related to transmission path switching control in a base station.
FIG. 10 is a sequence diagram illustrating a communication procedure when a transmission path used for communication between a mobile station and a base station is changed from a high-speed transmission path to a low-speed transmission path by a trigger from the mobile station.
FIG. 11 is a sequence diagram showing a communication procedure when a transmission path used for communication between a mobile station and a base station is changed from a low-speed transmission path to a high-speed transmission path by a trigger from the mobile station.
FIG. 12 is a sequence diagram showing a communication procedure when a transmission path used for communication between a mobile station and a base station is changed from a high-speed transmission path to a low-speed transmission path by a trigger from the base station.
FIG. 13 is a sequence diagram showing a communication procedure when a transmission path used for communication between a mobile station and a base station is changed from a low-speed transmission path to a high-speed transmission path by a trigger from the base station.
FIG. 14 is a diagram illustrating an example of a case where a transmission path used for communication between a mobile station and a base station is switched.
FIG. 15 is a diagram illustrating another example when switching of a transmission path used for communication between a mobile station and a base station is performed.
FIG. 16 is a sequence diagram showing an example of a communication procedure in a conventional mobile communication system.
[Explanation of symbols]
10 Mobile station
11 Control unit
12 Radio section
20 base stations
21 Control unit
22 Radio section
30 exchange
111 Timer controller
112 judgment part
121 transceiver
122 Wireless measurement unit
211 determination unit
221 transceiver
222 Wireless measurement unit

Claims (28)

In a mobile communication system in which a wireless transmission path is set between a mobile station and a base station to communicate with each other,
Communication quality determination means for determining the state of communication quality when communication is performed between a mobile station and a base station;
Another radio transmission providing a communication speed different from the communication speed provided by the radio transmission path as a radio transmission path used for communication between the mobile station and the base station according to the determination result by the communication quality determination means A transmission path switching control means for switching to a path,
The transmission path switching control means has a maximum transmission power even when the error rate is equal to or greater than a threshold in a mobile station performing communication on a high-speed transmission path, and even when the error rate is smaller than the threshold. In response to a request to change to the low-speed transmission path transmitted by the mobile station, the wireless transmission path used for communication between the mobile station and the base station is switching,
When a base station communicating on a high-speed transmission path receives a request to change from a mobile station to a low-speed transmission path, if the uplink interference measurement value is greater than the threshold, the error rate is greater than the threshold. Switch the wireless transmission path used for communication between the mobile station and the base station according to the change setting instruction to the low-speed transmission path transmitted by the base station,
In a mobile station that is communicating on a low-speed transmission path, when the transmission power is not controlled at the maximum value for a predetermined time, or when the error rate is smaller than the threshold regardless of the transmission power control value In addition, the wireless transmission path used for communication between the mobile station and the base station is switched according to the change request to the high-speed transmission path transmitted by the mobile station,
When a base station communicating on a low-speed transmission path receives a request to change from a mobile station to a high-speed transmission path, if the uplink interference measurement value is smaller than the threshold, the error rate is smaller than the threshold. In this case, a mobile communication system that switches a wireless transmission path used for communication between a mobile station and a base station in response to a change setting instruction for a high-speed transmission path transmitted by the base station. The mobile communication system according to claim 1, wherein
The communication quality determination means is a mobile communication system provided in a mobile station. The mobile communication system according to claim 1, wherein
The communication quality determination means is a mobile communication system provided in a base station. The mobile communication system according to any one of claims 1 to 3,
The communication quality determination means is a mobile communication system in which a state of communication quality is determined based on an error rate of a signal transmitted and received in communication between a mobile station and a base station. The mobile communication system according to claim 3,
The mobile communication system, wherein the communication quality determination means determines the state of communication quality based on an uplink interference amount. The mobile communication system according to claim 2,
The communication quality determination means determines whether the mobile station and the base station are instructed to increase the transmission power continuously for a predetermined time from the base station while the mobile station is controlling the transmission power at the maximum value. The mobile communication system which has the 1st transmission power control determination means obtained as a determination result of the state of communication quality in communication between The mobile communication system according to claim 2 or 6,
The communication quality determination means obtains, as a determination result of the communication quality state in the communication between the mobile station and the base station, whether or not the mobile station continuously controls the transmission power to a value other than the maximum value for a predetermined time. A mobile communication system having second transmission power control determination means. The mobile communication system according to any one of claims 1 to 7,
The transmission path switching control unit is used for communication between the mobile station and the base station when the communication quality determination unit obtains a determination result that the communication quality has deteriorated from a predetermined standard. A speed reduction control means for switching a wireless transmission path to another wireless transmission path that provides a communication speed lower than the communication speed provided by the wireless transmission path. The mobile communication system according to any one of claims 1 to 8,
The transmission path switching control unit is used for communication between the mobile station and the base station when the communication quality determination unit obtains a determination result that the communication quality is improved from a predetermined standard. A high-speed control means for switching the wireless transmission path to another wireless transmission path that provides a higher communication speed than the communication speed provided by the wireless transmission path. The mobile communication system according to any one of claims 1 to 9,
The transmission path switching control means includes a switchability determination means that is provided in the mobile station and determines whether communication with the base station is possible on the wireless transmission path after switching. A mobile communication system configured to switch a wireless transmission path when it is determined that communication is possible on the wireless transmission path after switching by means. The mobile communication system according to claim 10, wherein
The switching enable / disable determining means determines whether or not communication is possible on the wireless transmission path after switching based on whether or not signal synchronization can be established on the wireless transmission path after switching. . In mobile stations that communicate with each other by setting a wireless transmission path with the base station,
Communication quality determination means for determining the state of communication quality when communication is being performed with a base station;
The wireless transmission path used for communication with the base station is switched to another communication transmission path that provides a communication speed different from the communication speed provided by the wireless transmission path according to the determination result of the communication quality determination means. A transmission path change request means for requesting the base station to
The transmission path change request means is configured to transmit power from the maximum value even when the error rate is equal to or greater than a threshold value and when the error rate is smaller than the threshold value when performing communication on a high-speed transmission path. Further, when an increase instruction is made for a predetermined time, a change request to the low-speed transmission path is transmitted to the base station,
When communication is performed on a low-speed transmission path, when the transmission power is not controlled at the maximum value for a predetermined time, or when the error rate is smaller than the threshold value regardless of the transmission power control value. , Send a change request to the high-speed transmission path to the base station,
A mobile station in which a wireless transmission path used for communication between a mobile station and a base station is switched according to a request from the transmission path change request means to the base station. The mobile station according to claim 12,
The communication quality determining means is a mobile station that determines communication quality based on an error rate of a received signal from a base station. The mobile station according to claim 12,
The communication quality judging means determines whether or not an instruction to increase the transmission power is given from the base station for a predetermined time in a state where the transmission power is controlled at the maximum value, in communication with the base station. A mobile station comprising first transmission power control determination means obtained as a quality state determination result. The mobile station according to claim 12 or 14,
The second transmission power control means for obtaining, as a determination result of the state of communication quality in communication with the base station, whether or not the communication quality determination means continuously controls the transmission power to a value other than the maximum value for a predetermined time A mobile station having determination means. The mobile station according to any one of claims 12 to 15,
The transmission path change request means is a wireless transmission path used for communication with a base station when the communication quality determination means obtains a determination result that the communication quality has deteriorated from a predetermined standard. A mobile station having a transmission path speed reduction requesting means for requesting the base station to switch to another radio transmission path providing a communication speed lower than the communication speed provided by the wireless transmission path. The mobile station according to any one of claims 12 to 16,
The transmission path change requesting unit is a wireless transmission used for communication with a base station when the communication quality determining unit obtains a determination result that the communication quality is improved from a predetermined standard. A mobile station having a transmission path speed increase request unit that requests a base station to switch a path to another wireless transmission path that provides a higher communication speed than that provided by the wireless transmission path. The mobile station according to any one of claims 12 to 17,
Used to communicate with the base station when receiving a radio transmission path change setting instruction from the base station after requesting the base station to switch the radio transmission path from the transmission path change request means. A mobile station having transmission path switching control means for performing switching control of a wireless transmission path. The mobile station according to claim 18, wherein
The transmission path switching control means has switching possibility determination means for determining whether or not communication with the base station is possible in the wireless transmission path after switching, and the switching possibility determination means has A mobile station configured to perform switching control of a wireless transmission path when it is determined that communication is possible on the wireless transmission path. The mobile communication system according to claim 19,
The switching enable / disable determining means determines whether or not communication is possible on the switched wireless transmission path based on whether or not signal synchronization can be established on the switched wireless transmission path. In a base station configured to communicate with each other by setting a wireless transmission path with a mobile station,
Communication quality determination means for determining the communication quality state when communication is being performed with a mobile station;
The wireless transmission path used for communication with the mobile station is switched to another wireless transmission path that provides a communication speed different from the communication speed provided by the wireless transmission path according to the determination result of the communication quality determination means. A transmission path change setting instruction means for instructing the mobile station to
The transmission path change setting instruction means
In a mobile station communicating on a high-speed transmission path, an instruction to further increase the transmission power from the maximum value for a predetermined time even when the error rate is equal to or greater than the threshold and even when the error rate is smaller than the threshold. When continuously made, in response to the change request to the low-speed transmission path transmitted by the mobile station, a message for changing to the low-speed transmission path to the mobile station,
When communication is performed on a high-speed transmission path, when a change request to a low-speed transmission path is received from a mobile station, when an uplink interference measurement value is greater than a threshold value, or when an error rate is greater than a threshold value Next, send the change setting instruction to the low-speed transmission path to the mobile station,
In a mobile station that communicates on a low-speed transmission path, when the transmission power is not controlled at the maximum value for a predetermined time, or when the error rate is smaller than the threshold regardless of the transmission power control value In response to the change request to the high-speed transmission path transmitted by the mobile station, a message for changing to the high-speed transmission path is sent to the mobile station,
When communication is performed on a low-speed transmission path, when a change request from the mobile station to the high-speed transmission path is received, the uplink interference measurement value is smaller than the threshold value, or the error rate is smaller than the threshold value Then, send a change setting instruction to the high-speed transmission path to the mobile station,
A base station in which a wireless transmission path used for communication between a mobile station and a base station is switched in accordance with an instruction from the transmission path change setting instruction means to the mobile station. The base station according to claim 21,
  The base station configured to determine the state of communication quality based on an error rate of a signal received from a mobile station. The base station according to claim 21,
The base station system, wherein the communication quality determination means determines the state of communication quality based on an uplink interference amount. The base station according to any one of claims 21 to 23 ,
The transmission path change setting instruction means is a wireless transmission used for communication with a mobile station when the communication quality determination means obtains a determination result that the communication quality has deteriorated from a predetermined standard. A base station having a speed reduction instructing means for instructing to switch a path to another radio transmission path that provides a communication speed lower than the communication speed provided by the radio transmission path. The base station according to any one of claims 21 to 24 ,
The transmission path change setting instructing unit is a radio used for communication with a mobile station when the communication quality determining unit obtains a determination result that the communication quality is improved from a predetermined standard. High-speed instruction means for instructing to switch the transmission path to another wireless transmission path that provides a higher communication speed than the communication speed provided by the wireless transmission path
Base station with The base station according to any one of claims 21 to 25 ,
Transmission path switching control means for performing switching control of a wireless transmission path used for communication with the mobile station after the transmission path change setting instruction means instructs the mobile station to switch the wireless transmission path.
Base station with The base station according to claim 26 ,
When the transmission path switching control means receives an instruction to switch the wireless transmission path from the transmission path change setting instruction means to the mobile station, and receives a response to the instruction from the mobile station, Switchability determination means for determining whether or not communication between the two is possible on the wireless transmission path after switching
Have
A base station configured to perform switching control of a wireless transmission path when it is determined by the switching possibility determination means that communication is possible on the wireless transmission path after switching. The base station according to claim 27,
The base station configured to determine whether or not communication is possible on the wireless transmission path after switching based on whether or not signal synchronization can be established on the wireless transmission path after switching.

Images