JP2007019627A - System and method for radio communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a mobile station to continue communication without a break even when moving to a place where it is difficult to maintain a connection with a base station. <P>SOLUTION: In frequency band priority determination processing that the base station takes the initiative in, the mobile station 2 measures the location of itself by LCS and transmits the information on the position measurement to the base station 3. The base station 3 calculates the position of the mobile station 2 based upon the information on the position measurement from the mobile station 2, determines the priority of a frequency band that the mobile station 2 uses based upon the calculation result, and transmits it to the mobile station 2. The mobile station 2 determines the frequency band to be used based upon the priority of the frequency band that the base station 3 specifies. Consequently, the mobile station 2 in a place where a connection of communication is apt to be broken can preferentially select a frequency of the band advantageous in the communication, so the mobile station can communicate with the base station 3 without a break. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication system including a mobile station such as a mobile phone and a base station that performs wireless communication with the mobile station, and a wireless communication method of the system.

As a conventional wireless communication system, a mobile station measures the strength of reception levels of broadcast signals from a plurality of base stations, and base stations having a reception level equal to or higher than a predetermined value are candidates for communication, thereby improving communication reliability. A technique for enhancing the content has been proposed (see, for example, Patent Document 1).
JP 2004-128636 A

  By the way, as one method for further improving the reliability of communication, a method of selecting a frequency band to be used for communication between the mobile station and the base station based on the reception level of the broadcast signal can be considered. However, it is considered that a radio communication system employing such a method has the following problems.

  That is, as is well known, the propagation characteristics of the frequency differ depending on the band. In particular, the higher the frequency, the more difficult the radio wave travels to the back side of the building, and the phenomenon that communication between the base station and the mobile station is easily interrupted occurs. Therefore, regardless of the location of the mobile station, if the frequency band is specified based on the strength of the reception level, even if communication can be performed at the location where the mobile station uses the frequency specified for communication, the mobile station specified at this time When the frequency is a frequency in a high frequency band of, for example, 1.7 GHz band, even if the mobile station moves a little, the radio wave is difficult to go around and communication may be interrupted.

  The present invention has been made in view of the above points, and even when a mobile station moves to a place where it is difficult to maintain a connection with a base station, a wireless communication system and a wireless communication system that can continuously communicate without interruption An object is to provide a communication method.

(1) In a base station of a radio communication system, position acquisition means for acquiring position information of the mobile station of the radio communication system, and the mobile station based on the position information of the mobile station acquired by the position acquisition means Frequency band designation means for determining the priority of the frequency band used by the mobile station and designating it to the mobile station, and broadcast information for transmitting the priority of the frequency band designated by the use frequency band designation means as broadcast information And a transmission means.

  According to this configuration, the base station determines the priority of the frequency band suitable for use at the position according to the position of the mobile station and designates it to the mobile station. A mobile station in a complex location can be preferentially assigned a frequency in the low frequency band such as the 800 MHz band, and even if the mobile station moves to a location where it is difficult to maintain a connection with the base station, it is interrupted. It is possible to continue communication without any problems.

(2) In a mobile station of a wireless communication system, when broadcast information indicating the priority of a frequency band used by the own station is transmitted from a base station of the wireless communication system, it is used for communication based on the broadcast information A configuration including a use frequency band determining means for determining a frequency band is adopted.

  According to this configuration, since the mobile station receives the broadcast information transmitted from the base station and determines the frequency band to be used based on the broadcast information, for example, a place where there are many buildings or where the terrain is complicated If the mobile station is in a location, broadcast information indicating the priority of the frequency band in which radio waves can wrap around the building is sent from the base station to a location where it is difficult for the mobile station to maintain a connection with the base station. Even then, it is possible to continue communication without interruption.

(3) A configuration including the base station described in (1) above and the mobile station described in (2) above is adopted.

  According to this configuration, it is possible to provide a wireless communication system capable of continuing communication without interruption even when the mobile station moves to a place where it is difficult to maintain a connection with the base station.

(4) In a base station of a radio communication system, a use frequency band designating unit for designating a priority of a frequency band used for communication by a mobile station of the radio communication system in association with a position, and the use frequency band designating unit A configuration is provided that includes broadcast information transmission means for transmitting, as broadcast information, the correspondence between the designated position and the priority of the frequency band.

  According to this configuration, since the base station transmits the broadcast information in which the priority of the frequency band used for communication by the mobile station is associated with the position, the mobile station uses it for communication at the current position based on the broadcast information. The frequency band to be used can be determined. As a result, for example, when the mobile station is in a place where there are many buildings or where the terrain is complex, notification information indicating the priority of the frequency band in which radio waves can wrap around the building is sent from the base station. Thus, it is possible to continuously communicate with the base station without interruption.

(5) In the mobile station of the wireless communication system, position information acquisition means for acquiring the position information of the own station, and broadcast information indicating the correspondence between the position and the priority of the frequency band are transmitted from the base station of the wireless communication system. Then, a configuration is employed that includes a used frequency determining unit that determines a frequency band to be used based on the notification information and the position information acquired by the position information acquiring unit.

  According to this configuration, since broadcast information and position information are used to determine a frequency band, an optimal frequency band can be determined at the current position of the mobile station, and the rate at which communication with the base station is interrupted can be further reduced. Can be suppressed.

(6) The mobile station described in (5) above includes communication state information acquisition means for acquiring information about the communication state of the local station, and the used frequency determination means is acquired by the communication state information acquisition means. Frequency band used for communication based on the communication status information, the position information acquired by the position information acquisition means, and the broadcast information indicating the correspondence between the position specified by the base station and the priority of the frequency band The structure which determines is taken.

  According to this configuration, the broadcast information, the position information, and the communication state of the mobile station are used for determining the frequency band, so that a more optimal frequency band can be determined at the current position of the mobile station, The rate at which communication is interrupted can be kept lower than that of the invention (5).

(7) A configuration including the base station described in (4) above and the mobile station described in (5) or (6) above is adopted.

  According to this configuration, it is possible to provide a wireless communication system capable of continuing communication without interruption even when the mobile station moves to a place where it is difficult to maintain a connection with the base station.

(8) In a wireless communication method of a wireless communication system including a base station and a mobile station, the base station acquires position information of the mobile station, and a frequency band used by the mobile station based on the position information When the information indicating the priority of the frequency band used by the mobile station is specified from the base station, the mobile station uses it for communication based on the information. The frequency band to be determined is determined.

  According to this method, the base station determines the priority of the frequency band suitable for use at the position according to the position of the mobile station and designates it to the mobile station. A mobile station in a complex location can be preferentially assigned a frequency in the low frequency band such as the 800 MHz band, and even if the mobile station moves to a location where it is difficult to maintain a connection with the base station, it is interrupted. It is possible to continue communication without any problems.

(9) In a wireless communication method of a wireless communication system including a base station and a mobile station, the base station specifies a priority of a frequency band used for communication by the mobile station in association with a position to the mobile station. The mobile station acquires its own location information, and when broadcast information indicating the correspondence between the position and the priority of the frequency band is designated from the base station, the mobile station is based on the broadcast information and the location information. Determine the frequency band to use.

  According to this method, since broadcast information and position information are used to determine a frequency band, an optimal frequency band can be determined at the current position of the mobile station, and the rate at which communication with the base station is interrupted can be further reduced. Can be suppressed.

(10) In a wireless communication method of a wireless communication system including a base station and a mobile station, the base station specifies a priority of a frequency band used for communication by the mobile station in association with a position to the mobile station. The mobile station acquires its own position information and its own communication state information, and when the broadcast information indicating the correspondence between the position and the priority of the frequency band is designated from the base station, the broadcast information and A frequency band to be used is determined based on the position information and the communication state information.

  According to this method, since the broadcast information, the position information, and the communication state of the mobile station are used for determining the frequency band, it is possible to determine a more optimal frequency band at the current position of the mobile station, and The rate at which communication is interrupted can be kept lower than that of the invention (9).

  According to the present invention, since the priority of the frequency band suitable for use at the position is determined according to the position of the mobile station, the base station and the base station can be disconnected without interruption even in places where there are many buildings such as urban areas. Communication can be performed with a mobile station.

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

  FIG. 1 is a block diagram showing a schematic configuration of a radio communication system according to an embodiment of the present invention. In this figure, a wireless communication system 1 according to the present embodiment is a so-called mobile communication system, which includes a mobile station 2 and a base station 3, and performs communication between the mobile station 2 and the base station 3. Do. The mobile station 2 includes an LCS (LoCation Service) measurement unit 4 that acquires position information of the local station (mobile station 2), a radio transmission / reception unit 5 that performs transmission / reception of radio signals, a transmission / reception processing unit 6 that performs transmission / reception processing, A control unit (used frequency band determining means) 7 for controlling each part of the apparatus and a transmission / reception antenna 8 are provided. LCS is a location information acquisition method proposed by 3GPP (3rd Generation Partnership Project). The LCS measurement unit 4 corresponds to a position information acquisition unit. Moreover, the control part 7 respond | corresponds to a use frequency band determination means. The wireless transmission / reception unit 5 and the transmission / reception processing unit 6 constitute communication state information acquisition means.

  The base station 3 includes an LCS measurement unit 10 that acquires position information of the mobile station 2, a radio transmission / reception unit 11 that performs transmission / reception of radio signals, a transmission / reception processing unit 12 that performs transmission / reception processing, and a control unit 13 that controls each unit of the apparatus. And an antenna 14 for transmission / reception. The control unit 7 of the mobile station 2 and the control unit 13 of the base station 3 are both a CPU (central processing unit) (not shown), a program memory storing a control program for operating this CPU, and the operation of the CPU. And used work memory. The LCS measurement unit 10 corresponds to a position acquisition unit. The control unit 13 corresponds to a use frequency band specifying unit. Further, the wireless transmission / reception unit 11 and the transmission / reception processing unit 12 constitute notification information transmission means.

  Next, frequency band priority determination processing of the wireless communication system having the above configuration will be described. Here, the frequency band priority determination process will be described in order for each case, where the base station 3 is the lead and when the mobile station 2 is the lead.

<Baseband-led frequency band priority determination processing>
FIG. 2 is a flowchart showing an operation between the base station 3 and the mobile station 2 for explaining the frequency band priority determination process led by the base station. In this figure, first, the LCS measuring unit 4 of the mobile station 2 measures the position of the own station (mobile station 2) (step ST1). And after performing this position measurement, the information of position measurement is transmitted to the base station 3 (step ST2). In this case, the wireless transmission / reception unit 5 modulates the position measurement information, converts it into a wireless signal, and transmits it from the antenna 8.

  When the base station 3 receives the radio signal transmitted from the mobile station 2, the position measurement information is demodulated from the received radio signal, and the position of the mobile station 2 is determined based on the position measurement information at the demodulated mobile station 2. Calculate (step ST3). And the priority of the frequency band which the mobile station 2 uses based on the position of the calculated mobile station 2 is determined (step ST4). And the information of the priority of the frequency band which the mobile station 2 uses is transmitted to the mobile station 2 (step ST5). For example, when the mobile station 2 is in a place where there are many buildings or where the terrain is complicated, a frequency in a low frequency band such as the 800 MHz band is designated preferentially. On the other hand, when the mobile station 2 is in a place where there are few buildings or where the terrain is flat, a frequency in a high frequency band such as a 1.7 GHz band is designated preferentially.

  When the mobile station 2 receives the radio signal transmitted from the base station 3, it demodulates the frequency band priority information from the received radio signal, and the frequency to be used based on the frequency band priority obtained thereby. A band is determined (step ST6).

<Mobile station-led frequency band priority determination processing>
FIG. 3 is a flowchart showing an operation between the base station 3 and the mobile station 2 for explaining the mobile station-led frequency band priority determination process. In this figure, the control unit 13 of the base station 3 stores notification information indicating the priority of a frequency band to be used at each predetermined location, and the notification is performed when communicating with the mobile station 2 periodically. Information is transmitted to the mobile station 2 (step ST10). When the mobile station 2 receives the broadcast information transmitted from the base station 3 (step ST11), the LCS measurement unit 4 measures the position of the own station (step ST12). And the information of the measured position measurement is transmitted to the base station 3 (step ST13). When the position measurement information is transmitted from the mobile station 2, the base station 3 measures the position of the mobile station 2 using the LCS measurement unit 10 (step ST14). And the positional information which is a position measurement result is transmitted to the mobile station 2 (step ST15). When the mobile station 2 receives the location information transmitted from the base station 3, the mobile station 2 uses the frequency band priority of the previously received broadcast information and the location information of the mobile station 2 that has just been received. A priority is determined (step ST16).

Next, the flowchart shown in FIG. 4 shows details of the used frequency selection processing (step ST6 and step ST16) in both the base station-led frequency band priority determination processing and the mobile station-driven frequency band priority determination processing. Will be described with reference to FIG.
here,
n: Number of frequencies that the mobile station 2 can use for communication fj (1 ≦ j ≦ n): Frequency that the mobile station 2 can use for communication (f1>f2>...> fn in order of reception level of broadcast information. Suppose)
m: number of frequency bands that can be used by the mobile station 2 Fi (1 ≦ i ≦ m): frequency bands that can be used by the mobile station 2 (assuming that the priority is higher in the order of F1>F2>...> Fm).

  The mobile station 2 acquires priority level information (F1>...> Fm) of the frequency band to be used (step ST20). Next, “1” is substituted for i and j as initial values (step ST21). Next, it is determined whether the frequency fj that can be used for communication is included in the Fi band (step ST22). In this determination, when the frequency fj that can be used for communication is not included in the Fi band (No in step ST22), the mobile station 2 determines to perform communication at the frequency fj (step ST24). Further, when the frequency fj that can be used for communication is included in the Fi band (in the case of Yes in step ST22) and communication is possible in fj in step ST23 (in the case of Yes in step ST23), The mobile station 2 determines to communicate at the frequency fj (step ST24).

  On the other hand, when the frequency fj that can be used for communication by the mobile station 2 is included in the Fi band in Step ST22 (Yes in Step ST22), and the communication is not possible in fj in Step ST23. (In the case of No in step ST23), “1” is added to the value of j (step ST25), and the processing after step ST22 described above is performed on the frequency where the reception level of the broadcast information is weaker than fj (step ST26). In the case of Yes). Here, when there is no frequency at which the reception level of the broadcast information is weaker than fj, “1” is added to the value of i, and the value of j is set to “1” (step ST27), and the priority is lower than Fi. The processing after step ST22 described above is performed for the frequency band and the frequency with the highest reception level of the broadcast information (in the case of Yes in step ST28). Furthermore, in step ST28, when there is no frequency band having a lower priority than Fi, the processing after step ST20 described above is performed (in the case of No in step ST28).

  Thus, in the frequency band priority determination process led by the base station, the mobile station 2 measures the position of the mobile station 2 by the LCS measurement unit 4 and transmits the position measurement information to the base station 3. The station 3 calculates the position of the mobile station 2 based on the position measurement information from the mobile station 2, determines the priority of the frequency band used by the mobile station 2 based on the result, and transmits it to the mobile station 2 Then, the mobile station 2 determines the frequency band to be used based on the priority of the frequency band designated by the base station 3. On the other hand, in the frequency band priority determination process led by the mobile station, the base station 3 has information that has previously determined the priority of the frequency band to be used in each place, and uses this information as broadcast information for periodic communication with the mobile station 2 When the mobile station 2 receives the broadcast information, the LCS measurement unit 4 measures the position of the mobile station 2 and transmits the result to the base station 3. The position measurement information of the mobile station 2 is measured by the LCS measurement unit 4 and the result is transmitted to the mobile station 2. The mobile station 2 obtains the frequency obtained from the base station 3 first. The priority of the frequency band to be used is determined based on the priority of the band and the position information of the local station obtained now.

  Therefore, in any processing, the base station 3 determines the priority of the frequency band suitable for use at the position according to the position of the mobile station 2 and assigns it to the mobile station 2, so that, for example, A location where it is difficult for the mobile station 2 to maintain a connection with the base station 3 because it is possible to preferentially specify a frequency in a low frequency band such as the 800 MHz band for the mobile station 2 in many places or places with complicated terrain. Even if it moves to, it becomes possible to continue communication without interruption.

  In addition, by using broadcast information, position information, and the communication state of the mobile station to determine the frequency band, a more optimal frequency band can be determined at the current position of the mobile station, and communication with the base station can be performed. The rate of interruption can be further reduced.

  In the radio communication system according to the present embodiment, the position of the mobile station 2 is measured using the LCS measuring unit 4 or 10 in order to acquire the position information of the mobile station 2, but the base station It is also possible to acquire the position information of the mobile station 2 by determining in which sector of 3 the mobile station 2 is located.

  Further, in the radio communication system according to the present embodiment, the determination of which frequency band the mobile station 2 should use preferentially is performed in sequence in the exchange between the mobile station 2 and the base station 3. However, for example, the frequency band to be used may be determined according to the state of communication such as during communication and standby. For example, a high priority is given to a frequency in a band advantageous for communication during communication, and a priority indicated by broadcast information is given during standby.

  The present invention is suitable for application to a wireless communication system such as a mobile communication system for mobile phones.

The block diagram which shows schematic structure of the radio | wireless communications system which concerns on one embodiment of this invention 7 is a flowchart for explaining frequency band priority determination processing led by a base station in a wireless communication system according to an embodiment; Flowchart for explaining frequency band priority determination processing led by a mobile station in a wireless communication system according to an embodiment The flowchart for demonstrating the selection method of the frequency used in both the frequency band priority determination process of the base station initiative of the radio | wireless communications system which concerns on one embodiment, and the frequency band priority decision process of a mobile station initiative

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication system 2 Mobile station 3 Base station 4, 10 LCS measurement part 5, 11 Wireless transmission / reception part 6, 12 Transmission / reception processing part 7, 13 Control part 8, 14 Transmission / reception antenna

Claims (10)

In a base station of a wireless communication system,
Position acquisition means for acquiring position information of a mobile station of the wireless communication system;
A used frequency band specifying means for determining the priority of the frequency band used by the mobile station based on the position information of the mobile station acquired by the position acquiring means and specifying the priority to the mobile station;
Broadcast information transmitting means for transmitting the priority of the frequency band specified by the used frequency band specifying means as broadcast information;
A base station. In a mobile station of a wireless communication system,
When broadcast information indicating the priority of the frequency band used by the own station is transmitted from the base station of the wireless communication system, use frequency band determining means for determining the frequency band used for communication based on the broadcast information Mobile station equipped. A base station according to claim 1;
A mobile station according to claim 2;
A wireless communication system comprising: In a base station of a wireless communication system,
Use frequency band specifying means for specifying the priority of the frequency band used for communication by the mobile station of the wireless communication system in association with the position;
Broadcast information transmitting means for transmitting, as broadcast information, the correspondence between the position designated by the use frequency band designating means and the priority of the frequency band;
A base station. In a mobile station of a wireless communication system,
Position information acquisition means for acquiring position information of the own station;
When broadcast information indicating a correspondence relationship between position and frequency band priority is transmitted from a base station of the wireless communication system, it is used based on the broadcast information and the position information acquired by the position information acquisition means. A use frequency determining means for determining a frequency band;
A mobile station comprising: Comprising communication state information acquisition means for acquiring information about the communication state of the own station;
The use frequency determining means includes communication status information acquired by the communication status information acquiring means, position information acquired by the position information acquiring means, position specified by the base station, and priority of frequency band. The mobile station according to claim 5, wherein a frequency band to be used for communication is determined based on broadcast information indicating a correspondence relationship. A base station according to claim 4;
A mobile station according to claim 5 or claim 6;
A wireless communication system comprising: In a wireless communication method of a wireless communication system comprising a base station and a mobile station,
The base station acquires position information of the mobile station, determines the priority of the frequency band used by the mobile station based on the position information, and designates the mobile station,
The wireless communication method for determining a frequency band to be used for communication based on the information when the mobile station designates information indicating a priority of a frequency band to be used by the base station from the base station. In a wireless communication method of a wireless communication system comprising a base station and a mobile station,
The base station associates the priority of the frequency band used for communication by the mobile station with the location and designates the mobile station,
The mobile station acquires its own location information, and when broadcast information indicating a correspondence relationship between position and frequency band priority is specified from the base station, the mobile station uses the broadcast information and the location information. A wireless communication method for determining a frequency band to be performed. In a wireless communication method of a wireless communication system comprising a base station and a mobile station,
The base station associates the priority of the frequency band used for communication by the mobile station with the location and designates the mobile station,
The mobile station acquires the location information of the local station and the communication state information of the local station, and when the broadcast information indicating the correspondence between the position and the priority of the frequency band is designated from the base station, the broadcast information and the mobile station A wireless communication method for determining a frequency band to be used based on position information and the communication state information.

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