JP2008148134A - Mobile communication system, base station apparatus, and mobile radio terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication system, a base station apparatus, and a mobile radio terminal device which make the most use of infrastructure resources of an old system, have a great affinity with the old system, and are capable of utilizing a new system without deterioration of user's convenience in the old system. <P>SOLUTION: The mobile communication system comprises: a base station CS1 capable of communicating in both a first communication system equivalent to the new system and a second communication system equivalent to the old system; a base station CS2 for communicating in the second communication system; and a mobile radio terminal device 100 capable of communicating in the first communication system and the second communication system. When the mobile radio terminal device 100 waits for an incoming call in the second communication system, and a flag is received through a control channel from the standby base station, the base station is recognized as the base station CS1 corresponding to the first communication system as well, and switched to the first communication system to wait for an incoming call. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile communication system including two communication systems, for example, a new communication system called an existing PHS (Personal Handyphone System) and a next generation PHS (Personal Handyphone System).

  As is well known, mobile communication systems, such as mobile phone systems and PHS, have a large number of base stations and a mobile radio terminal device carried by the user communicates wirelessly. You can communicate from any location.

  Recently, with the spread of mobile phones, higher-speed communication services have been required, and new technologies such as HSDPA (High Speed Data Packet Access) and EV-DO (Evolution-Data Optimized) have been introduced. Development of next generation mobile communication systems is underway. Even in PHS, development of a new system called next-generation PHS that adopts new technologies such as OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multi-Input Multi-Output) is underway (for example, non- Patent Document 1).

However, the new system must be operated in an environment mixed with the old system, and the convenience of the user of the existing old system must not be impaired. There is also a demand for telecommunications carriers to minimize the cost of infrastructure renewal and to utilize the infrastructure assets of the old system as much as possible.
Wireless Communications Week at YRP, 2006.3.28-30, published by Ministry of Internal Affairs and Communications, Internet <http://www.wcw2006.jp/pdf/28_2.MIC.pdf#search='%EF%BC%A9%EF% BC% B4% EF% BC% B5% EF% BC% 8D% EF% BC% B2% 20% EF% BC% B3% EF% BC% A7% EF% BC% 98% 20BWA% 20% E6% AC% A1% E4% B8% 96% E4% BB% A3PHS '＞.

  The new mobile communication system must be operated in an environment mixed with the old system, and the convenience of the user of the existing old system must not be impaired. There is also a demand for telecommunications carriers to minimize the cost of infrastructure renewal and to utilize the infrastructure assets of the old system as much as possible.

  The present invention has been made in response to the above-mentioned demands. It utilizes the infrastructure assets of the old system as much as possible, has high compatibility with the old system, and can use the new system without impairing the convenience of users of the old system. An object of the present invention is to provide a mobile communication system, a base station apparatus, and a mobile radio terminal apparatus.

  In order to achieve the above object, the present invention provides a first base station capable of wireless communication using the first communication method and wireless communication using the second communication method, and a second base capable of wireless communication using the second communication method. A mobile communication system comprising a mobile radio terminal apparatus capable of accommodating a station in a network and capable of wireless communication by the first communication method and wireless communication by the second communication method, wherein the first base station is The mobile wireless terminal device includes a first communication unit that wirelessly communicates with the first base station using the first communication method, and includes a transmission unit that transmits identification information indicating that the first communication method can be used. Means, second communication means for wirelessly communicating with the first base station or the second base station by the second communication method, detection means for detecting identification information from the received signal of the second communication means, and second communication means Waiting for an incoming call When the detection means if detecting the identification information, to listen for incoming at the first communication means instead of the second communication means, and to configure and control means for controlling the first communication means.

  As described above, in the present invention, the first base station capable of wireless communication using the first communication method and the wireless communication using the second communication method, and the second base station capable of wireless communication using the second communication method are provided. The first base station transmits identification information indicating that the first communication method can be used by the second communication method, and the mobile radio terminal device receives an incoming call by the second communication method. If the identification information is detected while waiting, an incoming call is awaited by the first communication method instead of the second communication method.

  Therefore, according to the present invention, even when waiting for an incoming call by the second communication method, the mobile wireless terminal device can recognize that the first communication method can be used through the wireless signal of the second communication method. Switches to the first communication method and waits, so even if the two communication methods coexist, the first communication method can be actively used by utilizing the second communication method. In addition, since the mobile radio terminal apparatus that supports only the second communication system can also communicate through the first base station, it does not impair the convenience of the user of the mobile radio terminal apparatus and supports two communication systems. In the mobile radio terminal apparatus, both the first base station and the second base station can be used, the infrastructure assets of the two communication methods can be utilized, and a mobile communication system with high affinity can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of a mobile communication system according to an embodiment of the present invention. This mobile communication system accommodates, in a mobile communication network NW, a base station CS1 that performs both wireless communication by the first communication method and wireless communication by the second communication method, and a base station CS2 that performs only wireless communication by the second communication method. Then, the mobile radio terminal apparatus 100 and the mobile radio terminal apparatus 100 wirelessly communicate with each other using the first communication system or the second communication system, thereby providing a mobile communication service to the user.

  As the first communication method, a communication method adopted by the next-generation PHS using a communication technology such as OFDM or MIMO is assumed. On the other hand, as the second communication method, TDMA-TDD (Time Division Multiple Access-Time) is used. The communication method adopted by the existing PHS using Division Duplex) is assumed.

  For this reason, the base station CS2 is assumed to be a base station already provided. On the other hand, the base station CS1 is a base station newly established with the operation of the next-generation PHS, and adopts the first communication method as well as the existing user terminal devices adopting the second communication method. Wireless communication is also possible with next-generation PHS terminal devices. In other words, the existing user can use both the base station CS1 and the base station CS2 by the first communication method.

  Since the mobile radio terminal device 100 described later supports both the first communication method and the second communication method, the user can use both the base station CS1 and the base station CS2. In FIG. 1, one base station CS1 and one base station CS2 are shown, but many of them are installed in a wide range.

  As described above, the base station CS1 can communicate with the mobile radio terminal apparatus 100 by the second communication method similarly to the base station CS2, but the signal transmitted from the base station CS1 by the second communication method is the base station CS2. Unlike the signal of the second communication method transmitted from the CS2, it includes identification information indicating that the signal is transmitted from the base station CS1 that can also support the first communication method. This identification information is transmitted through the broadcast channel (BCCH) of the second communication method, for example. More specifically, a flag corresponding to the identification information is transmitted through a broadcast channel (BCCH).

  The mobile communication network NW incorporates an IP network in addition to a public network such as an ISDN (Integrated Services Digital Network) network, and depending on the type of service contracted by the user, a public network such as an ISDN network or other communication Communication through the network or IP communication through the IP network is performed. The base station CS2 can use either a public network or an IP network. Also, the base station CS1 can use either a public network or an IP network regardless of the communication method.

  The mobile radio terminal device 100 includes a first communication unit 10, a second communication unit 20, a voice processing unit 30, a display unit 40, an operation unit 50, a notification unit 60, a storage unit 70, and a control unit 80. And.

  The first communication unit 10 wirelessly communicates with the base station CS1 by the first communication method, and performs communication through the mobile communication network NW or the IP network via the base station CS1. The second communication unit 20 wirelessly communicates with the base stations CS1 and CS2 by the second communication method, and performs communication through the mobile communication network NW and the IP network via these base stations.

  In addition, the second communication unit 20 has a function of detecting the flag from the received signal in order to distinguish between the signal transmitted from the base station CS1 and the signal transmitted from the base station CS2. And the 1st communication part 10 and the 2nd communication part 20 are provided with the function to detect the level of a received signal, respectively.

  The audio processing unit 30 decodes the encoded audio data among the data demodulated by the first communication unit 10 or the second communication unit 20 to reproduce the audio signal, and outputs the sound from the built-in speaker 31. Thereby, the transmitted voice from the call partner station is transmitted to the user. The audio processing unit 30 encodes the audio signal input from the built-in microphone 32 to generate encoded audio data, and supplies the encoded audio data to the first communication unit 10 or the second communication unit 20 through the control unit 80.

  The display unit 40 is a display device using an LCD (Liquid Crystal Display) or the like, and displays various visual information such as text and images to the user. The operation unit 50 includes a plurality of key switches and the like and receives user requests. The notification unit 60 notifies the user of an incoming call by sound.

  The storage unit 70 stores the control program, control data, and application software of the control unit 80, and stores phone book data in which image data such as a phone number, a name, and a face photograph is associated, and transmitted / received mail data.

  The control unit 80 controls each unit of the mobile radio terminal apparatus 100 in an integrated manner, and operates according to a control program and control data stored in the storage unit 70. For example, the control unit 80 controls the first communication unit 10 or the second communication unit 20 to receive an incoming signal from a base station (CS1 or CS2) according to a predetermined communication protocol, and receives the incoming signal. In this case, the display unit 40 and the notification unit 60 are controlled to notify the occurrence of an incoming call, and a signal responding to the incoming call is sent to the first communication unit 10 or the second communication by the user's response operation through the operation unit 50. And an incoming call control function for establishing a communication link for performing voice communication and data communication.

  In addition, the control unit 80 executes application software stored in the storage unit 70, controls the first communication unit 10 or the second communication unit 20 to connect to the Internet, and browses the web such as a home page, e-mail, etc. And a function for displaying information (Web and e-mail) acquired by communication through the Internet in this way on the display unit 40, a function for displaying still images and moving images on the display unit 40, and the like.

  Further, the control unit 80 operates one or both of the first communication unit 10 and the second communication unit, receives a radio signal transmitted from the base station CS1 or the base station CS2, and based on this Then, carrier sense processing for searching for a base station that can obtain better communication quality is performed. This carrier sense process is performed during standby and during communication.

Next, the operation of the mobile communication system configured as described above will be described. In the following description, the carrier sense process will be described in detail.
First, carrier sense processing at the time of waiting for an incoming call will be described. FIG. 2 is a flowchart for explaining this process. The processing shown in this figure is realized by the control unit 80 operating according to the control program and control data stored in the storage unit 70, and starts when the incoming call waiting state is entered.

  First, in step 2a, the control unit 80 activates the first communication unit 10 (if it has already been activated), the control channel radio signal transmitted from the base station CS1 that can communicate with the first communication method. The base station CS1 is searched for, and the process proceeds to step 2b.

  In step 2b, the control unit 80 can detect whether or not the control channel transmitted from the base station CS1 in the first communication scheme has been received by the base station search in step 2a, that is, whether the base station using the first communication scheme has been detected. Determine whether or not. Here, when the base station (CS1) using the first communication method can be detected, the process proceeds to step 2c. On the other hand, when the base station cannot be detected, the process proceeds to step 2e.

  In step 2c, the control unit 80 synchronizes the reception timing of the first communication unit 10 with the reception timing of the control channel based on the control channel of the first communication method received in step 2a, and at a predetermined cycle. Control for intermittently receiving the control channel to be transmitted is started in accordance with the cycle, and the process proceeds to step 2d. Further, the first communication unit 10 detects the reception level of the control channel of the first communication method that has been intermittently received thereafter.

  When the control unit 80 detects an incoming signal addressed to the mobile radio terminal device 100 from the control channel by the intermittent reception, the control unit 80 controls the display unit 40 and the notification unit 60 to notify the user of the occurrence of the incoming call. When the user performs an operation to respond to an incoming call through the operation unit 50, a response process such as transmitting a response signal to the base station CS1 is performed. Here, the process up to the call following the response process is Description is omitted.

  In step 2d, the control unit 80 determines whether or not the reception level of the control channel of the first communication method received by the intermittent reception started in step 2c is equal to or lower than a preset level, that is, the necessity for handover occurs. It is determined whether or not. Here, when the necessity for the handover occurs, the process proceeds to step 2a. On the other hand, when the necessity for the handover does not occur, the occurrence of the necessity for the handover is monitored again at step 2d.

In step 2e, the control unit 80 stops the first communication unit 10 activated in step 2a to enter a sleep state (reception stop), and proceeds to step 2f.
In step 2f, the control unit 80 activates the second communication unit 20 (if it has already been activated), and controls the radio signal of the control channel transmitted from the base station (CS1 or CS2) by the second communication method. Attempt to receive, search for base station, and go to step 2g.

  In step 2g, the control unit 80 determines whether or not the control channel transmitted from the base station by the second communication method has been received by the base station search in step 2f, that is, whether or not the base station using the second communication method has been detected. Determine whether. Here, when the base station (CS1 or CS2) using the second communication method can be detected, the process proceeds to step 2h. On the other hand, when the base station cannot be detected, the process proceeds to step 2j.

  In step 2h, the control unit 80 synchronizes the reception timing of the second communication unit 20 with the reception timing of the control channel based on the control channel of the second communication method received in step 2f, and at a predetermined cycle. Control to intermittently receive the control channel to be transmitted is started in accordance with the cycle, and the process proceeds to step 2i. Further, the second communication unit 20 detects the reception level of the control channel of the second communication method that has been intermittently received thereafter.

  When the control unit 80 detects an incoming signal addressed to the mobile radio terminal device 100 from the control channel by the intermittent reception, the control unit 80 controls the display unit 40 and the notification unit 60 to notify the user of the occurrence of the incoming call. When the user performs an operation to respond to an incoming call through the operation unit 50, a response process such as transmitting a response signal to the base station is performed. Here, the process up to the call following the response process will be described. Is omitted.

  In step 2i, the control unit 80 determines whether or not the control channel received by the intermittent reception started in step 2f includes identification information (flag) indicating that the transmission source is the base station CS1, that is, It is determined whether or not the transmission source of the received control channel is the base station CS1. Here, when the transmission source is the base station CS1, the process proceeds to step 2k. On the other hand, when the transmission source is not the base station CS1, the process proceeds to step 2j.

  In step 2j, the control unit 80 determines whether or not the reception level of the control channel of the second communication method received by the intermittent reception started in step 2f is equal to or lower than a preset level, that is, the necessity for handover occurs. It is determined whether or not. Here, when the necessity for the handover occurs, the process proceeds to step 2f. On the other hand, when the necessity for the handover does not occur, the occurrence of the necessity for the handover is monitored again at step 2k.

  In step 2k, the control unit 80 activates the first communication unit 10 (if it is already activated), receives the control channel radio signal transmitted from the base station CS1 that can communicate with the first communication method. To search for the base station CS1 and move to step 2l. Here, the control unit 80 counts the loop number n in step 2k and steps 2l and 2m described later.

  In step 2l, the control unit 80 can detect whether or not the control channel transmitted from the base station CS1 in the first communication scheme has been received by the base station search in step 2k, that is, whether the base station using the first communication scheme has been detected. Determine whether or not. Here, when the base station (CS1) using the first communication method can be detected, the process proceeds to step 2o. On the other hand, when the base station cannot be detected, the process proceeds to step 2m.

  In step 2m, the control unit 80 determines whether or not the loop number n has exceeded a preset threshold value N. Here, if the number of loops n exceeds a preset threshold value N, the process proceeds to step 2n. On the other hand, if the number of loops n does not exceed the preset threshold value N, the process proceeds to step 2k. To do.

  In step 2n, the control unit 80 continues the intermittent reception by the second communication unit 20 (except when not passing through step 2h), waits for a certain time to elapse, and if the certain time elapses, the loop number n Is reset to “0”, the process proceeds to step 2k, and the search for the base station CS1 by the first communication method is performed again.

  When the number of loops reaches the threshold value in this way, there is a possibility that the loop operation will be repeated thereafter. In this case, the search is stopped for a certain time, so that battery waste can be prevented. Further, when a handover occurs in the second communication method while waiting for a certain time, the processing may be resumed from step 2f by exiting from this loop.

In step 2o, the control unit 80 stops the second communication unit 20 activated in step 2f to enter a sleep state (reception stop), and proceeds to step 2a.
Next, an operation in which the first communication unit 10 and the second communication unit 20 receive intermittently by the above-described carrier sense processing at the time of waiting for an incoming call will be described. 3 to 6 show an example thereof.

  First, as shown in FIG. 3, the control unit 80 activates the first communication unit 10 to search for the base station CS1 (step 2a). If the base station CS1 cannot be detected (step 2b), the first communication unit 10 (Step 2e), instead, the second communication unit 20 is activated to try to receive the radio signal of the control channel transmitted from the base station (CS1 or CS2) by the second communication method. Is searched (step 2f).

  When the control unit 80 detects the base station by the second communication method (step 2g), the control unit 80 determines the reception timing of the second communication unit 20 based on the control channel of the second communication method received by this detection. Then, control is started to intermittently receive the control channel transmitted in a predetermined cycle in synchronization with the reception timing (step 2h).

  And the control part 80 determines whether the identification information (flag) which shows that the transmission origin is base station CS1 is not contained in the control channel received by the said intermittent reception (step 2i). Here, since the flag is not included (the reception is not from the base station CS1 but from the base station CS2), the second communication unit 20 performs the intermittent reception as it is and monitors the necessity for handover. (Step 2k), waiting for an incoming call from the base station CS2.

  Next, as shown in FIG. 4, when the control unit 80 performs intermittent reception by the second communication unit 20 and is waiting for an incoming call from the base station CS2, the reception level of the control channel of the second communication method is When the occurrence of the necessity of handover is detected at a level lower than the preset level (step 2k), the control channel transmitted from the base station (CS1 or CS2) again by the second communication method by the second communication unit 20 is detected. Attempts to receive a radio signal and search for a base station (step 2f).

  When a new base station is detected by the second communication method (step 2g), the control unit 80 receives the reception timing of the second communication unit 20 based on the control channel of the second communication method received by this detection. Is synchronized with the reception timing of the control channel, and control for intermittently receiving the control channel transmitted in a predetermined cycle is started (step 2h).

  And the control part 80 determines whether the identification information (flag) which shows that the transmission origin is base station CS1 is not contained in the control channel received by intermittent reception (step 2i).

  Here, since the flag is included (the base station CS1), the control unit 80 stops the second communication unit 20 to enter the sleep state (reception stop) (step 2j), and again performs the first communication. When the base station CS1 is searched by activating the unit 10 (step 2a) and the base station CS1 can be detected (step 2b), the reception timing of the first communication unit 10 is set based on the control channel of the first communication method. In synchronization with the reception timing of the control channel, control for intermittently receiving the control channel transmitted in a predetermined cycle is started (step 2c).

  Subsequently, as shown in FIG. 5, the control unit 80 receives the control channel of the first communication method when intermittent reception is performed by the first communication unit 10 and waiting for an incoming call from the base station CS1. When the level becomes equal to or lower than the preset level and it is detected that the necessity for handover has occurred (step 2d), the first communication unit 10 again sets the control channel transmitted from the base station CS1 by the first communication method. A base station is searched by trying to receive a radio signal (step 2a).

  Then, when the new base station CS1 or the original base station CS1 is detected again by the first communication method (step 2b), the control unit 80 performs the first communication based on the control channel of the first communication method. The control unit 10 synchronizes the reception timing of the unit 10 with the reception timing of the control channel, and starts control to intermittently receive a control channel transmitted at a predetermined cycle (step 2c).

  On the other hand, instead of FIG. 5, for example, transition as shown in FIG. 6 is also conceivable. That is, the control unit 80 detects that the necessity of handover has occurred (step 2d), and searches for the base station CS1 by the first communication method again by the first communication unit 10 (step 2a). This is a case where it was not found (step 2b).

  In this case, the control unit 80 stops the reception of the first communication unit 10 (step 2e), activates the second communication unit 20 instead, and transmits from the base station (CS1 or CS2) by the second communication method. The base station is searched by trying to receive the radio signal of the control channel to be executed (step 2f).

  When the base station is detected by the second communication method (step 2g), the control unit 80 sets the reception timing of the second communication unit 20 to the reception timing of the control channel based on the control channel of the second communication method. Then, the control for intermittently receiving the control channel transmitted at a predetermined cycle is started in accordance with the cycle (step 2h).

  And the control part 80 determines whether the identification information (flag) which shows that the transmission origin is base station CS1 is not contained in the control channel received by intermittent reception (step 2i). Here, since the flag is not included (the reception is not from the base station CS1 but from the base station CS2), the intermittent reception by the second communication unit 20 is continuously performed as it is, and the necessity of handover is required. Is monitored (step 2k) while waiting for an incoming call from the base station CS2.

  Next, carrier sense processing during communication will be described. FIG. 7 is a flowchart for explaining this process. The processing shown in this figure is realized by the control unit 80 operating according to the control program and control data stored in the storage unit 70, and starts when communication is started.

  First, in step 7a, the control unit 80 determines whether the started communication is based on the first communication system or the second communication system. Here, if the started communication is based on the first communication method, the process proceeds to step 7b. On the other hand, if the initiated communication is based on the second communication system, the process proceeds to step 7h.

  In step 7b, the control unit 80 activates the second communication unit 20 in parallel with the first communication unit 10 already used in the communication using the first communication method, and enables a base station that can communicate using the second communication method ( Attempt to receive a radio signal of the control channel transmitted from CS1 or CS2), search for a base station, and proceed to Step 7c.

  Note that the base station search in step 7b is a second transmission from the other base station CS1 or base station CS2 than the radio signal of the second communication method transmitted from the base station CS1 used for communication at this time. Search for radio signals of two communication schemes preferentially. This is because the radio signal of the second communication method transmitted from the base station CS1 used for communication is very likely to decrease in the same manner when the reception level of the first communication method during communication decreases. Because.

  In step 7c, the control unit 80 synchronizes the reception timing of the second communication unit 20 with the reception timing of the control channel based on the control channel of the second communication method received in step 7b, and at a predetermined cycle. Control for intermittently receiving the control channel to be transmitted is started in accordance with a constant multiple of the period, and the process proceeds to step 7d.

  In step 7d, the control unit 80 determines whether or not the reception level of the first communication unit 10 performing communication has become equal to or lower than a preset level, that is, whether or not there is a need for handover in communication. . Here, when the necessity of handover occurs in the communication, the process proceeds to step 7e. On the other hand, when the necessity of handover does not occur in the communication, the necessity of handover is again generated in step 7d. Monitor.

  In step 7e, the control unit 80 controls the first communication unit 10 to try to receive a radio signal of the control channel transmitted from the base station (original CS1 or other CS1) that can communicate with the first communication method. The base station CS1 is searched, and the reception level is detected, and the process proceeds to step 7f.

  In step 7f, the control unit 80 determines whether or not the base station CS1 capable of obtaining a reception level suitable for handover can be detected by the base station search in step 7e. Here, when the base station CS1 capable of obtaining a reception level suitable for handover can be detected, the process proceeds to step 7g. On the other hand, when the base station CS1 cannot be detected, the process proceeds to step 7l.

  In step 7g, the control unit 80 controls the first communication unit 10 to perform a process of handing over to the base station CS1 detected by the base station search in step 7e, and proceeds to step 7b.

  On the other hand, in step 7h, the control unit 80 determines whether or not the control channel received during communication in the second communication scheme includes identification information (flag) indicating that the transmission source is the base station CS1, that is, Then, it is determined whether or not the base station used for communication is the base station CS1. Here, when the base station used for communication is the base station CS1, the process proceeds to step 7e. On the other hand, when the base station used for communication is not the base station CS1, the process proceeds to step 7i.

  In step 7i, the control unit 80 determines whether or not the reception level of the second communication unit 20 performing communication is equal to or lower than a preset level, that is, whether or not a need for handover has occurred in communication. . Here, when the necessity for handover occurs in the communication, the process proceeds to step 7j. On the other hand, when the necessity for handover does not occur in the communication, the necessity for handover is again generated in step 7i. Monitor.

  In step 7j, the control unit 80 controls the second communication unit 20 to receive the radio signal of the control channel transmitted from the base station (original CS2, other CS2 or CS1) that can communicate with the second communication method. Attempt to search for a base station and detect its reception level, then go to step 7k.

  Here, if the process has shifted from step 7f to step 7j, the second communication unit 20 has already received the second communication unit 20 based on the control channel of the second communication method received in step 7b in step 7c. Since the reception timing is synchronized with the reception timing of the control channel, the base station can be quickly detected by searching for the base station with this synchronization timing.

  In step 7k, the control unit 80 determines whether or not a base station capable of obtaining a reception level suitable for handover can be detected by the base station search in step 7j. If a base station capable of obtaining a reception level suitable for handover can be detected, the process proceeds to step 7l. On the other hand, if the base station cannot be detected, the process proceeds to step 7j. A base station that can obtain a reception level suitable for handover is searched.

  In step 7l, the control unit 80 determines whether or not the control channel received by the base station search in step 7j includes identification information (flag) indicating that the transmission source is the base station CS1, that is, in step 7k. It is determined whether or not the base station detected in step CS1 is CS1. Here, if the base station detected in step 7k is CS1, the process proceeds to step 7e, whereas if it is not CS1, the process proceeds to step 7m.

  In step 7m, the control unit 80 controls the second communication unit 20 to perform a process of handing over to the base station CS2 detected by the base station search in step 7j, and proceeds to step 7i.

  Next, an operation when one of the first communication unit 10 and the second communication unit 20 is communicating by the above-described carrier sense processing during communication will be described. 8 to 11 show an example thereof.

  First, as shown in FIG. 8, when an incoming signal arrives through the control channel by the first communication method and the first communication unit 10 receives this signal, the control unit 80 controls the display unit 40 and the notification unit 60, Inform the user of the incoming call. On the other hand, when the user operates the operation unit 50 to indicate the intention to respond to the incoming call, the control unit 80 that has detected this controls the first communication unit 10 to communicate with the base station CS1. A communication link is established between them and communication is started.

  Thereafter, the first communication unit 10 is controlled by the control unit 80 so as to receive the control channel and the dedicated information channel assigned to the mobile radio terminal apparatus 100 through the control channel as a downlink. For uplink, the control unit 80 controls the first communication unit 10 to perform transmission (not shown) on the dedicated information channel assigned to the mobile radio terminal apparatus 100 through the control channel.

  When communication is started in this way, the control unit 80 determines that the started communication is the first communication method (step 7a), and in parallel with the first communication unit 10 already used for communication. Then, the second communication unit 20 is activated to try to receive a control channel radio signal transmitted from a base station (CS1 or CS2) that can communicate with the second communication method, and searches for a base station (step 7b).

  The base station search here is a second signal transmitted from another base station CS1 or base station CS2 rather than a radio signal of the second communication method transmitted from the base station CS1 used for communication at this time. Search for a wireless signal of a communication method preferentially. This is because the radio signal of the second communication method transmitted from the base station CS1 used for communication is very likely to decrease in the same manner when the reception level of the first communication method during communication decreases. Because.

  Then, the control unit 80 synchronizes the reception timing of the second communication unit 20 with the reception timing of the control channel based on the received control channel of the second communication method, and transmits the control signal at a predetermined cycle. Control for intermittent reception of the channel is started in accordance with a cycle that is a constant multiple of the cycle (twice in the example of FIG. 8) (step 7c). Thereby, the mobile radio terminal apparatus 100 intermittently receives the control channel of the second communication method at a predetermined cycle by the second communication unit 20 while performing communication using the first communication unit 10.

  After that, as shown in FIG. 9, when the reception level of the control channel of the first communication method falls below a preset level and the necessity of handover occurs, and the control unit 80 detects this (step 7d), The control unit 80 tries to receive the radio signal of the control channel transmitted from the base station (original CS1 or other CS1) by the first communication method again by the first communication unit 10 and searches for the base station CS1. (Step 7e). In the example shown in FIG. 9, when another base station CS1 is detected (step 7f), the control unit 80 hands over to the base station CS1 (step 7g) and continues communication by the first communication unit 10. To do.

  On the other hand, when the base station CS1 cannot be detected as in the example illustrated in FIG. 10, the control unit 80 performs the second communication at the synchronization timing at which the second communication unit 20 is already synchronized in Step 7c. The base station (original CS2, other CS2 or CS1) is searched by receiving the radio signal of the system (step 7j).

  When a base station that can obtain a reception level suitable for handover can be detected by this base station search (step 7k), the control unit 80 indicates the base station CS1 in the control channel received from this base station. It is determined whether or not a flag is included (step 7l).

  In the example shown in FIG. 10, since the received control channel does not include the flag indicating the base station CS1, the control unit 80 hands over to the detected base station CS2 (step 7m) and performs the second communication. Communication using the unit 20 is performed.

  After that, as shown in FIG. 11, during the communication by the second communication unit 20, the reception level of the control channel of the second communication method becomes equal to or lower than the preset level, and the necessity of handover occurs, and this is controlled. When the unit 80 detects (step 7i), the control unit 80 uses the second communication unit 20 to retransmit the control channel radio signal transmitted from the base station (original CS2, other CS2 or CS1) using the second communication method. To search for a base station (step 7j).

  When a base station that can obtain a reception level suitable for handover can be detected by this base station search (step 7k), the control unit 80 indicates the base station CS1 in the control channel received from this base station. It is determined whether or not a flag is included (step 7l).

  In the example illustrated in FIG. 11, since the flag is included, the control unit 80 recognizes that the transmission source of the received control channel is the base station CS1. Therefore, the control unit 80 tries to receive the control channel radio signal transmitted from the base station CS1 by the first communication method by the first communication unit 10 and searches for the base station CS1 (step 7e). Thereby, since the base station CS1 is detected (step 7f), the control unit 80 hands over to the base station CS1 (step 7g), and the first communication unit 10 continues communication.

  Then, the control unit 80 activates the second communication unit 20 in parallel with the first communication unit 10 that has started communication in this way, and can communicate with the second communication method (other CS1 or CS2). The base station is searched by trying to receive the radio signal of the control channel transmitted from (step 7b).

  The base station search here is a second signal transmitted from another base station CS1 or base station CS2 rather than a radio signal of the second communication method transmitted from the base station CS1 used for communication at this time. Search for a wireless signal of a communication method preferentially. This is because the radio signal of the second communication method transmitted from the base station CS1 used for communication is very likely to decrease in the same manner when the reception level of the first communication method during communication decreases. Because.

  Then, the control unit 80 synchronizes the reception timing of the second communication unit 20 with the reception timing of the control channel based on the received control channel of the second communication method, and transmits the control signal at a predetermined cycle. Control for intermittent reception of the channel is started in accordance with a cycle that is a constant multiple of the cycle (twice in the example of FIG. 11) (step 7c).

  Thereby, the mobile radio terminal apparatus 100 receives the control channel of the second communication method intermittently at a predetermined cycle by the second communication unit 20 while performing communication using the first communication unit 10 again. In preparation for handover from the base station CS1 of the first communication system to the base station of the second communication system.

  As described above, in the mobile communication system configured as described above, the base station CS1 capable of communication using both the first communication method corresponding to the new system and the second communication method corresponding to the old system, and the second communication method described above. When the mobile radio terminal apparatus 100 includes a base station CS2 that communicates with the mobile radio terminal apparatus 100 that can communicate with the first communication system and the second communication system, and the mobile radio terminal apparatus 100 is waiting for an incoming call using the second communication system, it is used for standby When a flag is received from a base station through a control channel, the base station recognizes that it is a base station CS1 that also supports the first communication method, and switches to the first communication method to wait for an incoming call. .

  Therefore, according to the mobile communication system having the above configuration, the mobile radio terminal apparatus 100 recognizes that the first communication method can be used through the control channel of the second communication method even when waiting for an incoming call by the second communication method. In this case, since the standby is performed by switching to the first communication method, even if the two communication methods coexist, the new system can be actively used by utilizing the old system.

  In addition, since a user using a mobile radio terminal apparatus that supports only the second communication method can also communicate through the base station CS1, the convenience of the user of the old system is not impaired, while the mobile radio terminal apparatus 100 Can use both the base station CS1 and the base station CS2 for communication, so the infrastructure assets of the old system can be utilized and the affinity is high.

  In the mobile communication system configured as described above, when the mobile radio terminal apparatus 100 performs communication using the second communication method, when the flag is received from the base station used for communication through the control channel, the base station Recognizing that the base station CS1 also supports one communication method, the communication is performed by switching to the first communication method.

  Therefore, according to the mobile communication system configured as described above, when the mobile radio terminal apparatus 100 recognizes that the first communication method can be used through the control channel even when the communication is performed using the second communication method. Since the communication is switched to the first communication method, the new system can be actively used by utilizing the old system even if the two communication methods coexist.

  In addition, when communicating with the first communication method, in preparation for handover, the base station is searched for with the second communication method, and synchronization is established to communicate with the base station using the second communication method. I have to. For this reason, even if the handover in the first communication scheme cannot be performed and the handover to the base station in the second communication scheme is performed, the influence on the communication due to the handover can be minimized.

  Furthermore, when communicating with the first communication method, the base station of the second communication method that searches for handover in advance gives priority to the base station that is not used for communication over the base station that is used for communication. I'm trying to explore. For this reason, even if the handover in the first communication method cannot be performed and the handover to the base station in the second communication method is performed, the synchronized base station in the second communication method is also insufficient for the handover. You can avoid falling.

  In addition, when communicating using the first communication method, the control channel is received from the base station of the second communication method that has been searched for in advance for handover in a cycle that is a constant multiple of the cycle in which the control channel is transmitted. I am doing so. For this reason, by increasing the period, it is possible to reduce the power consumption in preparation for the handover to the base station of the second communication method.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. Further, for example, a configuration in which some components are deleted from all the components shown in the embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.

  As an example, for example, the present invention is described as an example because it is suitable for a conventional PHS and a next-generation PHS. However, the present invention can be applied to a combination of other communication systems, and the same effect can be obtained. Play.

  In the above embodiment, the case where the base station CS1 capable of both the first communication method and the second communication method and the base station CS2 capable of only the communication using the second communication method are exemplified. It is not limited. For example, when the base station CS1 is installed in the vicinity of the base station CS2, the base station CS1 is configured to be capable of only communication using the first communication method, and the base station CS2 transmits a flag through the control channel, You may make it alert | report to the mobile radio | wireless terminal apparatus 100 from base station CS2 that the 1st communication system can be performed by base station CS1. As described above, even when the base station of the first communication scheme and the base station of the second communication scheme have different system configurations, the same effect is obtained.

  In this case, the base station CS1 and the base station CS2 can be synchronized with each other by operating in synchronization with a common reference signal supplied from the wired network, and smooth handover can be realized. Further, synchronization may be established by radio communication between the base station CS1 and the base station CS2.

In addition, when control information needs to be exchanged between the base station CS1 and the base station CS2, the control information may be exchanged via a center device on the network in the same manner as well-known handover control. In addition, control information may be exchanged by radio communication between the base station CS1 and the base station CS2.
In addition, it goes without saying that the present invention can be similarly implemented even if various modifications are made without departing from the gist of the present invention.

The circuit block diagram which shows the structure of one Embodiment of the mobile communication system concerning this invention. The flowchart for demonstrating the operation | movement at the time of the incoming call waiting of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of the incoming call waiting of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of the incoming call waiting of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of the incoming call waiting of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of the incoming call waiting of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The flowchart for demonstrating the operation | movement at the time of communication of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of communication of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of communication of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of communication of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG. The figure for demonstrating the operation | movement at the time of communication of the mobile radio | wireless terminal apparatus of the mobile communication system shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... 1st communication part, 20 ... 2nd communication part, 30 ... Audio | voice processing part, 31 ... Speaker, 32 ... Microphone, 40 ... Display part, 50 ... Operation part, 60 ... Notification part, 70 ... Memory | storage part, 80 ... Control unit, 100 ... mobile radio terminal, CS1 ... base station, CS2 ... base station, NW ... network.

Claims (15)

A first base station capable of wireless communication using the first communication method and wireless communication using the second communication method, and a second base station capable of wireless communication using the second communication method are accommodated in a network, and A mobile communication system comprising a mobile wireless terminal device capable of wireless communication by a first communication method and wireless communication by the second communication method,
The first base station is
Transmission means for transmitting identification information indicating that the first communication method can be used by the second communication method;
The mobile radio terminal device
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the first base station or the second base station by the second communication method;
Detecting means for detecting the identification information from the received signal of the second communication means;
When the detection means detects identification information while waiting for an incoming call by the second communication means, the first communication means is controlled so that the first communication means waits for an incoming call instead of the second communication means. A mobile communication system. A first base station capable of wireless communication using the first communication method and wireless communication using the second communication method, and a second base station capable of wireless communication using the second communication method are accommodated in a network, and A mobile communication system comprising a mobile wireless terminal device capable of wireless communication by a first communication method and wireless communication by the second communication method,
The first base station is
Transmission means for transmitting identification information indicating that the first communication method can be used by the second communication method;
The mobile radio terminal device
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the first base station or the second base station by the second communication method;
Detecting means for detecting the identification information from the received signal of the second communication means;
When the detection means detects identification information when communication is being performed by the second communication means, the first communication means is controlled to communicate with the first communication means instead of the second communication means. A mobile communication system comprising a control means. A first base station capable of wireless communication using the first communication method and wireless communication using the second communication method, and a second base station capable of wireless communication using the second communication method are accommodated in a network, and A mobile communication system comprising a mobile wireless terminal device capable of wireless communication by a first communication method and wireless communication by the second communication method,
The first base station is
Transmission means for transmitting identification information indicating that the first communication method can be used by the second communication method;
The mobile radio terminal device
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the first base station or the second base station by the second communication method;
Synchronization control means for performing synchronization for communicating with the first base station or the second base station using the second communication means when communicating by the first communication means;
When the communication is performed by the first communication unit, when the handover is necessary, the second communication unit is configured such that the synchronization control unit performs handover to the synchronized base station and continues the communication by the second communication unit. A mobile communication system comprising control means for controlling the means.   The said synchronization control means gives priority to base stations other than the 1st base station which is communicating by the said 1st communication means, and performs the synchronization for communicating with this base station, It is characterized by the above-mentioned. Mobile communication system.   The synchronization control means receives a synchronization signal wirelessly communicated by the first base station or the second base station at a predetermined cycle at a constant multiple of the cycle, and synchronizes for communicating with the base station The mobile communication system according to claim 3, wherein: A mobile communication system comprising a first base station capable of wireless communication using the first communication method and a wireless communication using the second communication method, and a second base station capable of wireless communication using the second communication method accommodated in a network. Mobile radio terminal equipment used in
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the first base station or the second base station by the second communication method;
Detecting means for detecting identification information indicating that the first communication method transmitted from the first base station can be used, from a received signal of the second communication means;
When the detection means detects identification information while waiting for an incoming call by the second communication means, the first communication means is controlled so that the first communication means waits for an incoming call instead of the second communication means. A mobile radio terminal apparatus comprising: A mobile communication system comprising a first base station capable of wireless communication using the first communication method and a wireless communication using the second communication method, and a second base station capable of wireless communication using the second communication method accommodated in a network. Mobile radio terminal equipment used in
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the first base station or the second base station by the second communication method;
Detecting means for detecting identification information indicating that the first communication method transmitted from the first base station can be used, from a received signal of the second communication means;
When the detection means detects identification information when communication is being performed by the second communication means, the first communication means is controlled to communicate with the first communication means instead of the second communication means. And a mobile wireless terminal apparatus. A mobile communication system comprising a first base station capable of wireless communication using the first communication method and a wireless communication using the second communication method, and a second base station capable of wireless communication using the second communication method accommodated in a network. Mobile radio terminal equipment used in
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the first base station or the second base station by the second communication method;
Synchronization control means for performing synchronization for communicating with the first base station or the second base station using the second communication means when communicating by the first communication means;
When the communication is performed by the first communication unit, when the handover is necessary, the second communication unit is configured such that the synchronization control unit performs handover to the synchronized base station and continues the communication by the second communication unit. A mobile radio terminal apparatus comprising: control means for controlling the means.   9. The synchronization control means prioritizes a base station other than the first base station communicating with the first communication means, and performs synchronization for communication with the base station. Mobile radio terminal equipment.   The synchronization control means receives a synchronization signal wirelessly communicated by the first base station or the second base station at a predetermined cycle at a constant multiple of the cycle, and synchronizes for communicating with the base station The mobile radio terminal apparatus according to claim 8, wherein: A base station apparatus used in a mobile communication system including a first base station that wirelessly communicates with a mobile radio terminal apparatus using a first communication method.
First communication means for wirelessly communicating with the mobile wireless terminal device by the first communication method;
A second communication means for wirelessly communicating with the mobile wireless terminal device by the second communication method;
A base station apparatus comprising: a transmission control unit that transmits identification information indicating that the second communication method can be used by the first communication method. A first base station capable of wireless communication according to the first communication method and a second base station capable of wireless communication according to the second communication method are accommodated in a network, and wireless communication according to the first communication method is provided. A mobile communication system comprising a mobile radio terminal device capable of radio communication by the second communication method,
The second base station is
Transmission means for transmitting identification information indicating that the first communication method can be used by the second communication method;
The mobile radio terminal device
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the second base station by the second communication method;
Detecting means for detecting the identification information from the received signal of the second communication means;
When the detection means detects identification information while waiting for an incoming call by the second communication means, the first communication means is controlled so that the first communication means waits for an incoming call instead of the second communication means. A mobile communication system. A first base station capable of wireless communication according to the first communication method and a second base station capable of wireless communication according to the second communication method are accommodated in a network, and wireless communication according to the first communication method is provided. A mobile communication system comprising a mobile radio terminal device capable of radio communication by the second communication method,
The second base station is
Transmission means for transmitting identification information indicating that the first communication method can be used by the second communication method;
The mobile radio terminal device
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the second base station by the second communication method;
Detecting means for detecting the identification information from the received signal of the second communication means;
When the detection means detects identification information when communication is being performed by the second communication means, the first communication means is controlled to communicate with the first communication means instead of the second communication means. A mobile communication system comprising a control means. A mobile radio terminal apparatus used in a mobile communication system including a first base station capable of radio communication according to a first communication scheme and a second base station capable of radio communication according to the second communication scheme accommodated in a network. There,
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the second base station by the second communication method;
Detecting means for detecting identification information indicating that the first communication method transmitted from the first base station can be used, from a received signal of the second communication means;
When the detection means detects identification information while waiting for an incoming call by the second communication means, the first communication means is controlled so that the first communication means waits for an incoming call instead of the second communication means. A mobile radio terminal apparatus comprising: A mobile radio terminal apparatus used in a mobile communication system including a first base station capable of radio communication according to a first communication scheme and a second base station capable of radio communication according to the second communication scheme accommodated in a network. There,
First communication means for wirelessly communicating with the first base station by the first communication method;
A second communication means for wirelessly communicating with the second base station by the second communication method;
Detecting means for detecting identification information indicating that the first communication method transmitted from the first base station can be used, from a received signal of the second communication means;
When the detection means detects identification information when communication is being performed by the second communication means, the first communication means is controlled to communicate with the first communication means instead of the second communication means. And a mobile wireless terminal apparatus.

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