JP2008085525A - Base station device selection method, wireless communication system, portable terminal device, and base station device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a user to quickly perform high-speed packet communication by selecting and connecting a base station device having a light communication load at the start of communication. <P>SOLUTION: This base station device selection method is composed as follows. A portable terminal device 110 makes a connection request to a communicable base station device 120. The base station device which receives the connection request, transmits channel information and the number of available slots. The portable terminal device receives the channel information and the number of available slots. When the number of available slots exceeds a threshold preset in the portable terminal device, the base station device is selected as a wireless communication party so as to perform wireless communication with the selected base station device via a channel indicated in the channel information. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio communication system including a mobile terminal device and a plurality of base station devices that perform radio communication with the mobile terminal device, and in particular, a base station device that performs radio communication with the mobile terminal device is selected. The present invention relates to a base station device selection method, a wireless communication system, a mobile terminal device, and a base station device.

  When performing a voice call in a mobile terminal device such as a mobile phone, the mobile terminal device first attempts wireless communication with a plurality of base station devices spread around a number of points as the end of a communication network. A wireless communication is established through a channel assigned to the base station apparatus, and a voice call is started. In packet communication, a channel opened to each mobile terminal device in a voice call can be further time-divided, and the divided time slots can be assigned to different mobile terminal devices.

  Whether the desired communication is a voice call or packet communication, the mobile terminal device first searches the electric field strength of the surrounding base station device by a method called open search in order to ensure its own wireless communication quality, A base station apparatus with strong electric field strength is selected. In addition, the mobile terminal device continuously monitors the electric field strength of the surrounding base station device while continuing wireless communication with the selected base station device, and the base station device that is in communication with the movement of the mobile terminal device or a change in the communication status When the radio wave from is weakened, the connection is switched to another base station apparatus (handover), and communication is continued.

  As described above, when the handover of the base station apparatus is performed based only on the electric field strength, communication connections are concentrated on the base station apparatus with strong radio waves, in other words, the base station apparatus with good installation conditions. As a result, the communication load of the base station apparatus also increases, and the communication speed with each mobile terminal apparatus decreases significantly.

However, in the conventional wireless communication system, there is no way of grasping such a decrease in communication speed, and it is forced to perform packet communication while maintaining the low speed, and it is assumed that the packet communication is progressing at a low speed. I had to do it. In order to alleviate such a problem, a technique for switching a connection destination from a base station apparatus in communication to a base station apparatus having a light communication load is known (for example, Patent Document 1).
JP 2002-159038 A

  However, in such a technique, the amount of communication is constantly calculated in all base station devices, and the amount of communication must be periodically transmitted to neighboring base station devices, and the base station device in communication must notify the information. I had to. Further, every time the information is acquired, the mobile terminal device side has to measure the electric field strength of the base station device again, which increases the processing load.

  In addition, this technique is a technique related to handover of a base station apparatus, and the problem that communication connections concentrate on a specific base station apparatus at the start of communication has not been solved.

  The present invention has been made in view of the above-described problems of the conventional wireless communication system, and an object of the present invention is to select and connect a base station apparatus having a light communication load from the start of communication by the mobile terminal apparatus. Accordingly, a new and improved base station apparatus selection method, radio communication system, portable terminal apparatus, and base station apparatus capable of quickly performing high-speed packet communication are provided.

  Further, another object of the present invention is to minimize the processing load of the base station device by investigating and selecting a base station device with a light communication load in an independent and real-time manner by the mobile terminal device. It is to provide a new and improved base station apparatus selection method, radio communication system, portable terminal apparatus, and base station apparatus that can reduce the operation cost.

  In order to solve the above problems, according to an aspect of the present invention, there is provided a base station apparatus selection method for selecting a base station apparatus that performs radio communication with a mobile terminal apparatus from a plurality of communicable base station apparatuses, A connection request step in which the mobile terminal device makes a connection request to a communicable base station device, channel information indicating a channel to which the base station device that has received the connection request can connect, and a current empty slot in the base station device Information transmitting step for transmitting the number, an information receiving step for the mobile terminal device to receive the channel information and the number of empty slots, and the mobile terminal device having an empty slot number equal to or greater than a preset threshold in the mobile terminal device If so, a base station selection step of selecting the base station device as a wireless communication partner, and the mobile terminal device performs wireless communication with the base station device selected via the channel indicated in the channel information. Characterized in that it comprises a portable radio communication step of performing, a base station apparatus selection method is provided.

  The portable terminal device grasps the communication permission status of the base station device at the start of communication and during communication, and selects and connects a base station device with a light communication load. With this configuration, high-speed and stable packet communication can be performed from the start of communication. In addition, the mobile terminal device actively searches and selects such a base station device with a light communication load in real time, so that the processing load of the base station device can be minimized, and the introduction cost and operation cost It is also possible to reduce this.

  The mobile terminal device further includes an electric field strength measurement step for measuring electric field strength with a communicable base station device, and the connection request step sequentially performs connection requests in the order of strong electric field strength measured in the electric field strength measurement step, In the base station selection step, the base station device may be selected as a wireless communication partner when the number of empty slots sequentially received in the information reception step becomes equal to or greater than a preset threshold value.

  In the portable terminal device, a desired value of the number of empty slots is set in advance as a threshold value, and when the empty slot becomes equal to or greater than the threshold value, that is, at a communication speed at which packet communication is performed comfortably, immediately with the base station device. Connecting. Since the portable terminal device can acquire the number of empty slots by an existing connection request, it is possible to realize high-speed packet communication with almost no new processing load.

  When there is no base station apparatus in which the number of empty slots is equal to or greater than the threshold, the connection request process, the information transmission process, and the information reception process may be repeated. Moreover, it is good also as reducing each threshold value preset in the portable terminal device and repeating each process.

  By repeating such a process, it is possible to reliably select a base station apparatus having an empty slot equal to or greater than a threshold value. Further, by repeating each step with the threshold lowered, it is possible to select a base station apparatus that has the best communication permission status at present.

  The portable terminal device further includes a retransmission request step for periodically requesting transmission of the number of empty slots to the base station device performing wireless communication. When the received number of empty slots falls below a threshold value, the electric field strength measuring step, connection The request process, the information transmission process, and the information reception process may be executed again.

  The communication permission status of the base station device changes according to the communication status with other mobile terminal devices. Therefore, it is monitored whether or not it is maintained above the threshold even during wireless communication, and if it is not maintained, a new base station device is selected. In this way, the number of empty slots is always maintained above the threshold value, and the mobile terminal device can maintain high-speed packet communication.

  Moreover, it is good also as including the threshold value change process which changes a threshold value according to a user's request | requirement.

  With this configuration, the user can freely set a threshold, and can give priority to either time or certainty of communication according to his / her convenience and the capacity of a packet to be transmitted. For example, the threshold value is increased when priority is given to speed even if certainty is sacrificed, and the threshold value is decreased when priority is given to certainty.

  The portable terminal device further includes an electric field strength measurement step for measuring electric field strength with a communicable base station device, and the connection request step includes all base station devices whose electric field strength measured in the electric field strength measurement step is equal to or higher than a predetermined level. The base station selection step may select the base station apparatus having the largest number of empty slots as the wireless communication partner among all the empty slots received in the information receiving step.

  Instead of requesting connection in order of increasing electric field strength, the present invention makes a connection request to all base station devices whose electric field strength is equal to or higher than a predetermined level, and selects a base station device having the largest number of empty slots. Connect. In such a configuration, processing is increased in that connection requests are made to a plurality of base station apparatuses. However, since the packet communication can be performed with the base station apparatus having the largest number of empty slots at that time, a higher speed can be achieved. Packet communication can be realized.

  In order to solve the above problems, according to another aspect of the present invention, a wireless communication system including a mobile terminal device and a plurality of base station devices that perform wireless communication with the mobile terminal device, the mobile terminal device Is a connection request unit that makes a connection request to a communicable base station device among a plurality of base station devices, channel information indicating channels that can be connected from the base station device that has made a connection request, and the number of empty slots. If the information receiving unit to receive, the number of empty slots is equal to or greater than a preset threshold in the mobile terminal device, the base station selecting unit that selects the base station device as a wireless communication partner, and the channel indicated in the channel information A mobile wireless communication unit that performs wireless communication with the base station device selected via the base station device, and the base station device, in response to the connection request, obtains channel information and the current number of empty slots in the base station device. Information transmitting unit for signal, characterized in that it comprises a wireless communication system is provided.

  Also provided are a mobile terminal device and a base station device used in the wireless communication system.

  The components corresponding to the dependent claims in the base station device selection method described above and the description thereof can be applied to the wireless communication system, the mobile terminal device, and the base station device.

  A computer can also provide a program that functions as the mobile terminal device or the base station device.

  As described above, according to the present invention, since a base station apparatus with a light communication load is selected and connected from the start of communication, high-speed packet communication can be quickly performed. By investigating and selecting a lightly loaded base station device in real time by the mobile terminal device, it becomes possible to minimize the processing load on the base station device and reduce the introduction cost and operation cost. . Furthermore, by distributing the communication load among a plurality of base station devices, the communication load is not concentrated on a specific base station device, and the communication efficiency of the entire wireless communication system can be improved.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

(Wireless communication system 100)
First, the configuration of each device in the wireless communication system 100 according to the present embodiment and the relationship thereof will be described.

  FIG. 1 is a block diagram illustrating a schematic configuration of a wireless communication system 100. The wireless communication system 100 includes a mobile terminal device 110, a base station device 120, a communication network 130, and a management server 140.

  The mobile terminal device 110 includes electronic devices capable of wireless communication, such as a PHS (Personal Handyphone System) terminal, a mobile phone, a PDA (Personal Digital Assistant), and a notebook personal computer, and uses the mobile terminal device 110. Voice data and packet data are transmitted and received based on user requests.

  The base station device 120 is arranged at many points (electric poles, building rooftops, telephone boxes, subway platforms, company building ceilings, etc.) as the end of the communication network 130, and is capable of wireless communication with the mobile terminal device 110 and the communication network 130. The communication between the mobile terminal device 110 and the communication network 130 is relayed. Further, the base station apparatus 120 has a plurality of channels (for example, 3 channels and 7 channels) for performing wireless communication with the mobile terminal apparatus 110, and a plurality of slots (for example, one channel for each channel). 4 slots) are provided.

  The communication network 130 is formed by a dedicated network or the Internet network, and supports communication between the base station apparatuses 120 to be connected for communication under the management of the management server 140.

  When voice communication is performed using the wireless communication system 100 described above, the mobile terminal device 110 attempts wireless communication with a plurality of base station devices 120 that are spread around multiple points as the end of the communication network 130, The base station apparatus 120 is selected, wireless communication is established with the base station apparatus 120 through the allocated channel, and a voice call is started.

  In addition, the mobile terminal device 110 always monitors the electric field strength of the surrounding base station device 120 while communicating with the selected base station device 120, and is in communication with the movement of the mobile terminal device 110 or a change in communication status. When the radio wave from the device 120 weakens, the connection is switched to another base station device 120 (handover), and communication is continued.

  In packet communication, a channel that is opened to each mobile terminal device 110 in a voice call is further time-divisioned, and time division multiplex communication (TDMA: Time) in which the divided slots (time slots) are assigned to different mobile terminal devices. Division Multiple Access) is used. By such time division multiplex communication, radio waves of one frequency can be used by a plurality of mobile terminal apparatuses 110, and the base station apparatus 120 can perform wireless communication simultaneously with the plurality of mobile terminal apparatuses 110.

  For example, in the base station apparatus 120 capable of accommodating 3 channels for communication and storing 4 slots in one channel, a total of 12 slots can be used. For this base station apparatus 120, six mobile terminal apparatuses When 110 performs packet communication at the same time, the remaining six slots become the number of empty slots “6”. When the mobile terminal device 110 is connected to only one slot, for example, when the communication speed is 8 kbps, and one channel is occupied, 4 channels (3 channels) at a communication speed of 32 kbps for 4 slots. When + CCH (Control Channels 1 channel) is occupied, packet communication can be performed at a communication speed of 128 kbps.

  With such a wireless communication system 100, a user can use not only a voice call such as a fixed telephone but also a service through transmission / reception of e-mails and the Web. It has come to be applied to a wide range of services.

  However, in the packet communication, if the base station device 120 is selected based on only the electric field strength, communication connections are concentrated on the base station device 120 with good installation conditions, and accordingly, the communication load of the base station device 120 increases. Thus, the communication speed with each portable terminal device 110 is significantly reduced.

  In the wireless communication system 100 according to the embodiment of the present invention, the mobile terminal device 110 can quickly perform high-speed packet communication by selecting and connecting the base station device 120 with a light communication load from the start of communication. In addition, the mobile terminal device 110 actively searches and selects the base station device 120 with a light communication load in real time, thereby minimizing the processing load of the base station device 120 and reducing the introduction cost and the operation cost. It is possible to plan.

  FIG. 2 is an explanatory diagram for explaining the concept of the wireless communication system 100 of the present embodiment. In FIG. 2, three base station apparatuses 120A, 120B, and 120C are installed at different positions, and the mobile terminal apparatus 110 is positioned therebetween. Under such circumstances, if there is no obstacle between the base station devices 120A, 120B, 120C and the mobile terminal device 110, the electric field strength has a value corresponding to the distance D between them.

  In FIG. 2, the mobile terminal device 110 is located in the communication areas 150A and 150B among the communication areas 150A, 150B, and 150C of the base station devices 120A, 120B, and 120C, but is in the communication area 150C. Absent. Accordingly, communication with the base station device 120C is disabled.

  Here, considering only a voice call, the mobile terminal apparatus 110 should be connected to the base station apparatus 120A having a strong electric field strength, that is, a short interval D. However, according to the present embodiment, a new parameter such as the number of empty slots is provided, and the base station apparatus to be connected is not determined only by the interval D. For example, when the mobile terminal device 110 desires the base station device 120 having 10 or more empty slots, if the empty slot of the base station device 120A is 4 and the empty slot of the base station device 120B is 12, the electric field strength Regardless, the base station apparatus 120B is selected as the wireless communication partner.

  Hereinafter, the mobile terminal device 110 and the base station device 120 that constitute the wireless communication system according to the present embodiment will be described in detail.

(Mobile terminal device 110)
FIG. 3 is a configuration block diagram illustrating a schematic configuration related to the hardware of the mobile terminal device 110. The portable terminal device 110 includes a terminal control unit 210, a terminal storage unit 212, a display unit 214, an operation unit 216, a voice input unit 218, a voice output unit 220, a portable wireless communication unit 222, and an antenna unit. 224 and an electric field strength measuring unit 226.

  The terminal control unit 210 manages and controls the entire portable terminal device 110 by a semiconductor integrated circuit including a central processing unit (CPU). The terminal control unit 210 uses the program stored in the terminal storage unit 212 and naturally performs a call function and an e-mail distribution function using the mobile terminal device 110. However, a connection request unit 310, an information reception unit 312 described later, It also functions as a base station selection unit 314 and a retransmission request unit 316.

The terminal storage unit 212 includes ROM, RAM, E ² PROM, nonvolatile RAM, flash memory, HDD (Hard Disk Drive), and the like, and is used by the program processed by the terminal control unit 210 and the portable terminal device 110. Store possible terminal information and the like.

  The display unit 214 is configured by a color or monochrome display, and is stored in the terminal storage unit 212 or provided from an application server (not shown) via a communication network. User Interface) can be displayed. It is also possible to refer to the setting of the mobile terminal device 110 and the terminal information.

  The operation unit 216 includes switches such as a keyboard, a cross key, and a joystick, and receives a user operation input. The operation unit 216 also functions as a threshold value changing unit 318 described later.

  The voice input unit 218 includes a device such as a microphone that can acquire the voice of the called party, and converts the voice of the user input during voice call into a voice signal.

  The voice output unit 220 is composed of a device such as a speaker that can output voice, and converts the voice signal of the caller into voice and outputs the voice. Further, a ring tone, an operation sound by the operation unit 216, an alarm sound, and the like can be output.

  The mobile wireless communication unit 222 performs wireless communication with the base station apparatus 120 in the mobile phone network, and transmits and receives voice signals or packet signals via the communication network. Such voice signals and packet signals can realize voice calls between users and transmission / reception of electronic data through the communication network 130.

  The antenna unit 224 converts an audio signal or a packet signal from the mobile wireless communication unit 222 into a radio signal, and converts the radio signal from the base station device 120 into an electrical signal that can be used by the mobile terminal device 110. The antenna unit 224 may have two antennas. In this case, the reception state of radio waves is monitored, and an antenna having a good reception state is selected and used (diversity method).

  The field strength measuring unit 226 measures the field strength of a plurality of base station devices 120 that can communicate via the antenna unit 224, particularly the field strength in received radio waves, as an index for selecting the base station device 120 to be connected for communication. To do.

  As described above, the mobile terminal device 110 according to the present embodiment performs voice communication and packet communication while establishing communication with the base station device 120. Hereinafter, a specific operation of the mobile terminal device 110 will be described in detail with respect to packet communication.

  FIG. 4 is a functional block diagram illustrating schematic functions of the mobile terminal device 110. The mobile terminal device 110 includes a connection request unit 310, an information reception unit 312, a base station selection unit 314, a retransmission request unit 316, and a threshold change unit 318.

  Based on the electric field strengths of the plurality of base station devices 120 measured by the electric field strength measuring unit 226, the connection requesting unit 310 makes a connection request to the base station device 120 in descending order of the electric field strength.

  The information receiving unit 312 receives channel information indicating a connectable channel and the current number of empty slots in the base station device 120 from the base station device 120 to which the connection request unit 310 has requested connection.

  The base station selection unit 314 uses the base station device 120 in which the number of empty slots received from the base station device 120 is equal to or greater than a threshold (for example, “10”) set in advance in the mobile terminal device 110 as a wireless communication partner. select. And the portable radio | wireless communication part 222 starts radio | wireless communication with the base station apparatus 120 selected by the base station selection part 314 through the channel shown by channel information.

  In portable terminal device 110, when a desired value of the number of empty slots is preset as a threshold and the number of empty slots is equal to or greater than the threshold, that is, when a communication speed at which packet communication can be performed comfortably can be achieved, the base station Immediately connects to device 120. Since the mobile terminal device 110 can acquire the number of empty slots by an existing connection request, it is possible to realize high-speed packet communication with almost no new processing load.

  When there is no base station apparatus in which the number of empty slots is equal to or greater than the threshold value, connection requests and information reception by the connection request unit 310 and the information reception unit 312 are repeated. Alternatively, the threshold value set in advance in the mobile terminal device 110 may be somewhat lowered and each step may be repeated.

  By repeating such a process, it is possible to surely select a base station apparatus whose number of empty slots is equal to or greater than a threshold value, and by repeating each process with a lower threshold value, the most allowable communication status is currently A good base station apparatus can be selected.

  In addition, the base station selection unit 314 has the number of empty slots equal to or greater than the threshold even after the comparison of all the empty slots of all the communicable base station devices 120 and the thresholds in the communication terminal device. If there is not, the connection request or information reception may be repeated from the base station apparatus 120 with the strongest electric field strength, or the search for the number of empty slots is given up here, and the base station apparatus 120 with the strongest electric field strength is given here. The communication may be forcibly started.

  After the base station device 120 is selected and communication is started, the retransmission request unit 316 periodically makes a transmission request for the number of empty slots to the base station device 120 that is performing wireless communication. Then, when the number of empty slots received from the base station device 120 becomes less than the threshold, the connection request unit 310, the information reception unit 312 and the base station selection unit 314 are caused to execute the base station device selection of this embodiment again.

  The communication permission status of the base station device 120 changes according to the communication status with other mobile terminal devices 110. Therefore, it is monitored whether or not it is maintained at a threshold value or higher even during wireless communication, and when it is not maintained, a new base station device 120 is selected. In this way, the number of empty slots is always kept above the threshold, and the mobile terminal device 110 can maintain high-speed packet communication.

  The threshold value changing unit 318 changes the threshold value according to a user request. The threshold value described above is defined by default (for example, “10”) at the time of shipment of the mobile terminal device 110, but the threshold value can be changed afterwards. The user can freely set the threshold value by using the threshold value changing unit 318, and give priority to either time or certainty of communication according to his / her convenience and the capacity of the packet to be transmitted. For example, when speed is prioritized even at the expense of certainty, the threshold is increased, and when certainty is prioritized, the threshold is decreased.

(Base station apparatus 120)
FIG. 5 is a configuration block diagram showing a schematic configuration of base station apparatus 120. The base station apparatus 120 includes a base station control unit 410, a base station storage unit 412, a base station radio communication unit 414, and a communication network connection unit 416.

  The base station control unit 410 manages and controls the entire base station apparatus 120 using a semiconductor integrated circuit including a central processing unit (CPU, DSP). The base station control unit 410 relays the mobile terminal device 110 and the communication network 130 using a program stored in the base station storage unit 412. In addition, the base station control unit 410 may serve as an information transmission unit that transmits channel information indicating connectable channels and the current number of empty slots in the base station device 120 in response to a connection request from the mobile terminal device 110. Function.

The base station storage unit 412 includes a ROM, RAM, E ² PROM, nonvolatile RAM, flash memory, HDD (Hard Disk Drive), and the like, and stores programs processed by the base station control unit 410.

  The base station wireless communication unit 414 transmits and receives voice data, packet data, and the like by wireless communication with the mobile terminal device 110 under the control of the base station control unit 410. For example, in the above-described PHS base station apparatus, channels and slots are assigned to a plurality of mobile terminal apparatuses 110, and time division multiplex communication is executed with the mobile terminal apparatuses 110 respectively connected to the plurality of slots. .

  The communication network connection unit 416 performs wireless or wired communication with the communication network 130 under the control of the base station control unit 410.

  As described above, the mobile terminal device 110 and the base station device 120 of the present embodiment described above grasp the communication permission status of the base station device 120 at the start of communication and during communication, and select and connect a base station device with a light communication load. To do. With this configuration, high-speed and stable packet communication can be performed from the start of communication. In addition, the mobile terminal device actively searches and selects such a base station device with a light communication load in real time, so that the processing load of the base station device can be minimized, and the introduction cost and operation cost Can be reduced.

  A program that functions as the mobile terminal device 110 or the base station device 120 can also be provided by a computer.

(Base station device selection method)
Next, a base station device selection method for selecting a base station device that performs wireless communication with the mobile terminal device 110 from the above-described base station device 120 will be described in detail. Here, the base station apparatus selection method in mobile terminal apparatus 110 and the base station apparatus selection method in base station apparatus 120 are described separately.

  FIG. 6 is a flowchart showing the flow of the base station device selection method in the mobile terminal device 110. Before starting the base station apparatus selection method, the user can freely change the threshold set at the time of shipment. For example, when packet communication is attempted with the base station apparatus 120 having 10 or more empty slots, the threshold is set to “10” as the number of empty slots (S500).

  When starting packet communication, first, the field strength measuring unit 226 measures the field strength with the communicable base station device 120 (S502), and based on the result, whether there is a communicable base station device 120. It is determined whether or not (S504). If there is a communicable base station apparatus 120, all the base station apparatuses 120 are extracted, and the connection request unit 310 makes a connection request to the base station apparatus 120 having the strongest electric field strength (S506). If there is no communicable base station device 120, it is determined whether the number of retries has reached the upper limit (S508). If the upper limit is reached, packet communication is abandoned (S510), and if the upper limit is not reached. It repeats from an electric field strength measurement process (S502).

  When the base station apparatus 120 returns the channel information and the number of empty slots in response to the connection request (S506), the information receiving unit 312 receives the channel information and the number of empty slots (S512), and the base station selecting unit 314 Determines whether the number of empty slots is equal to or greater than a threshold value set in advance in the mobile terminal device 110 (S514). Here, if it is equal to or greater than the threshold value, the base station device 120 is selected as a wireless communication partner at that time (S516).

  Here, if it is not equal to or greater than the threshold value, it is determined whether or not the connection request step (S506) has been performed for all communicable base station devices 120 (S518). The process is repeated from the connection request step (S506) for the strong base station device 120 (S520). If all the steps are performed, the base station apparatus 120 having the strongest electric field strength is again targeted (S522), and the process is repeated from the connection request step (S506). In this connection request repeating step (S522), the threshold value may be lowered in order to perform the subsequent communication connection more reliably, for example, the empty slot may be decremented to “9” and repeated from the connection request step (S506). Further, communication may be forcibly started with the base station apparatus 120 having the strongest electric field strength.

  In this way, when the base station device 120 that is the wireless communication partner is selected, wireless communication with the selected base station device is started via the channel indicated in the channel information (S524). Even after the wireless communication is started in this manner, the retransmission request unit 310 periodically requests the base station apparatus 120 that is performing wireless communication to transmit the number of empty slots (S526), and the information receiving unit 312 The number of empty slots is received (S528), and it is determined whether or not the number of empty slots is equal to or greater than a threshold value (S530). Here, when the value is less than the threshold value, the wireless communication is continued and is executed again from the electric field strength measurement step (S502), and when the base station device 120 in which the number of empty slots is equal to or greater than the threshold value is found, Switching takes place.

  FIG. 7 is a flowchart showing a flow of a base station device selection method in the base station device 120. Here, it waits for a signal from the mobile terminal device 110 (S600), and when there is a connection request in the connection request step (S506), it checks the number of empty slots indicating the current communication permission status in its own station (S602). Then, the channel information and the number of empty slots of the own station are transmitted to the mobile terminal device 110 that has made the connection request (S604).

(Another example of base station apparatus selection method)
Next, another example of the base station device selection method for selecting a base station device that performs wireless communication with the mobile terminal device 110 from the above-described base station device 120 will be described in detail. Here, instead of requesting connection in order of increasing electric field strength, a connection request is made to all base station devices 120 whose electric field strength is equal to or higher than a predetermined level, and the base station device 120 having the largest number of empty slots is extracted. And connect. Since the base station apparatus selection method in the base station apparatus 120 is substantially the same as the process described using FIG. 7, the description is omitted here, and the base station apparatus selection method in the mobile terminal apparatus 110 in which the processes are different. Only explained.

  FIG. 8 is a flowchart showing the flow of the base station device selection method in the mobile terminal device 110. As described above, before starting the base station apparatus selection method, the user can freely change the setting of the threshold set at the time of shipment (S700).

  When starting packet communication, first, the field strength measuring unit 226 measures the field strength with the communicable base station device 120 (S702), and based on the result, whether there is a communicable base station device 120. It is determined whether or not (S704). If there is a communicable base station apparatus 120, all the base station apparatuses 120 are extracted, and the connection request unit 310 requests connection to all base station apparatuses whose electric field strength measured by the electric field strength measuring unit 226 is equal to or higher than a predetermined level. (S706). Here, the predetermined level refers to a level at which wireless communication can be performed stably. If there is no communicable base station device 120, it is determined whether the number of retries has reached the upper limit (S708). If the upper limit has been reached, packet communication is abandoned (S710). It repeats from a measurement process (S702).

  When all the base station devices 120 return channel information and the number of empty slots in response to the connection request, the information receiving unit 312 receives the channel information and the number of empty slots (S712), and the base station selecting unit 314 Selects the base station device 120 having the largest number of empty slots among all the empty slots as a wireless communication partner (S716).

  Thus, when the base station device 120 to be a wireless communication partner is selected, wireless communication with the selected base station device is started via the channel indicated in the channel information (S724). Even after the wireless communication is started in this manner, the retransmission request unit 310 periodically makes a transmission request for the number of empty slots to the base station apparatus 120 that is performing wireless communication (S726), and the information receiving unit 312 The number of empty slots is received (S728), and it is determined whether or not the number of empty slots is maintained within a predetermined range (S730). Here, if it is determined that it is not maintained, the wireless communication is continued and is executed again from the electric field strength measurement step (S702), and when the base station device 120 in which the number of empty slots is equal to or greater than the threshold is found, Switching of the base station apparatus 120 is performed.

  In such a configuration, although processing related to acquisition of the number of empty slots has increased, packet communication can be performed with the base station apparatus having the largest number of empty slots at that time, so that higher-speed packet communication can be realized.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, a configuration in which one mobile terminal device selects one base station device and performs packet communication is described. However, the combination is not limited to this, for example, one device The mobile terminal device may be connected to a plurality of base station devices, and the divided packets may be transmitted / received to / from each base station device in parallel, and the base station according to the present embodiment is provided for each communication line of the divided packets. The station device selection method may be applied.

  In addition, each process in the base station apparatus selection method of this specification does not necessarily need to process in time series along the order described as a flowchart, and is a process (for example, parallel processing or individual execution) performed in parallel or individually. (Processing by object) may also be included.

  The present invention relates to a radio communication system including a mobile terminal device and a plurality of base station devices that perform radio communication with the mobile terminal device, and in particular, a base station that selects a base station device that performs radio communication with the mobile terminal device. The present invention is applicable to a station apparatus selection method, a wireless communication system, a mobile terminal apparatus, and a base station apparatus.

1 is a block diagram showing a schematic configuration of a wireless communication system. It is explanatory drawing for demonstrating the concept of the radio | wireless communications system of this embodiment. It is the block diagram which showed the schematic structure regarding the hardware of a portable terminal device. It is the functional block diagram which showed the schematic function of the portable terminal device. It is the block diagram which showed the schematic structure of the base station apparatus. It is the flowchart figure which showed the flow of the base station apparatus selection method in a portable terminal device. It is the flowchart figure which showed the flow of the base station apparatus selection method in a base station apparatus. It is the flowchart which showed the flow of the base station apparatus selection method in a portable terminal device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Wireless communication system 110 ... Portable terminal device 120 ... Base station apparatus 222 ... Portable wireless communication part 226 ... Electric field strength measurement part 310 ... Connection request part 312 ... Information receiving part 314 ... Base station selection part 316 ... Retransmission request part 318 ... threshold changing units S500 and S700 ... threshold changing steps S502 and S702 ... field strength measuring steps S506 and S706 ... connection requesting steps S512 and S712 ... information receiving steps S516 and S716 ... base station selecting steps S524 and S724 ... portable wireless communication step S530 , S730 ... retransmission request step S604 ... information transmission step

Claims (10)

A base station device selection method for selecting a base station device that performs wireless communication with a mobile terminal device from a plurality of communicable base station devices,
A connection request step in which the mobile terminal device makes a connection request to the base station device;
The base station apparatus that has received the connection request transmits channel information indicating channels that can be connected and the current number of empty slots in the base station apparatus; and
An information receiving step in which the mobile terminal device receives the channel information and the number of empty slots;
If the mobile terminal device has a number of empty slots equal to or greater than a preset threshold in the mobile terminal device, a base station selection step of selecting the base station device as a wireless communication partner;
A portable wireless communication process in which the portable terminal device performs wireless communication with the selected base station device via the channel indicated in the channel information;
The base station apparatus selection method characterized by including. The portable terminal device further includes an electric field strength measurement step of measuring electric field strength with the communicable base station device,
In the connection request step, the connection request is sequentially performed in order of the electric field strength measured in the electric field strength measurement step,
The base station selecting step selects the base station device as a wireless communication partner when the number of empty slots sequentially received in the information receiving step becomes equal to or greater than a preset threshold value. Item 4. The base station apparatus selection method according to Item 1.   The base station apparatus selection method according to claim 2, wherein when there is no base station apparatus whose number of empty slots is equal to or greater than a threshold, the connection request process, the information transmission process, and the information reception process are repeated.   3. The base station according to claim 2, wherein when there is no base station apparatus in which the number of empty slots is equal to or greater than a threshold, the connection request process, the information transmission process, and the information reception process are repeated with the threshold decreased. Device selection method. The mobile terminal device further includes a retransmission request step of periodically making a transmission request for the number of empty slots to the base station device performing wireless communication,
5. The method according to claim 2, wherein when the number of received empty slots becomes less than a threshold value, the electric field strength measurement step, the connection request step, the information transmission step, the information reception step, and the base station selection step are executed again. The base station apparatus selection method according to any one of the above.   The base station apparatus selection method according to claim 1, further comprising a threshold value changing step of changing the threshold value according to a user request. The portable terminal device further includes an electric field strength measurement step of measuring electric field strength with the communicable base station device,
In the connection request step, a connection request is made to all the base station devices whose electric field strength measured in the electric field strength measurement step is a predetermined level or more,
The base station selecting step selects a base station device having the largest number of empty slots as a wireless communication partner among all the empty slots received in the information receiving step. The base station apparatus selection method described in 1. A wireless communication system including a mobile terminal device and a plurality of base station devices that perform wireless communication with the mobile terminal device,
The portable terminal device
A connection request unit that makes a connection request to a communicable base station device among the plurality of base station devices;
An information receiving unit for receiving channel information indicating connectable channels and the number of empty slots from the base station apparatus that has made the connection request;
If the number of empty slots is equal to or greater than a preset threshold in the mobile terminal device, a base station selection unit that selects the base station device as a wireless communication partner;
A portable wireless communication unit that performs wireless communication with the selected base station device via the channel indicated in the channel information;
With
The base station device
In response to the connection request, an information transmission unit that transmits channel information and the current number of empty slots in the base station device,
A wireless communication system comprising: A mobile terminal device that performs wireless communication with a plurality of base station devices,
A connection request unit that makes a connection request to a base station device capable of communication among the plurality of base station devices;
An information receiving unit for receiving channel information indicating connectable channels and the number of empty slots from the base station apparatus that has made the connection request;
If the number of empty slots is equal to or greater than a preset threshold in the mobile terminal device, a base station selection unit that selects the base station device as a wireless communication partner;
A portable wireless communication unit that performs wireless communication with the selected base station device via the channel indicated in the channel information;
A portable terminal device comprising: A base station device that performs wireless communication with a mobile terminal device,
In response to a connection request from the mobile terminal device, an information transmission unit that transmits channel information indicating a connectable channel and the current number of empty slots in the base station device;
A base station apparatus comprising:

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