JP2006332753A - Mobile communication system, mobile station apparatus, and access control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication system, a mobile station apparatus, and an access control method for decreasing a time until a call is connected after a call request by building up a contrivance whereby a mobile station selects an optimum base station and can be connected thereto. <P>SOLUTION: The mobile station apparatus decides a congestion state on the basis of notice information transmitted from mobile station apparatuses (access points A to D) and makes a call to an optimum base station apparatus on the basis of a result of the decision. Further, the mobile station apparatus uses a transmission capacity being a requested load and a transmission rate for decision criteria of the congestion state and reserves a transmission path required for communication in advance to carry out the communication. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mobile communication system, a mobile station apparatus, and an access control method in an environment where service areas of base stations for mobile stations overlap.

  FIG. 9 shows a configuration example of a mobile communication system in an environment in which base stations are densely placed, that is, a so-called pico cell service area is constructed. As is clear from FIG. 9, service areas are overlapped by a plurality of base stations (BS). For this reason, the mobile stations scattered in the area must select a base station (BS) as a connection destination from a plurality of base stations (BS).

By the way, a plurality of base station radio devices are arranged under the control of the base station control device, and a plurality of communication channels are provided that enable simultaneous transmission from a plurality of mobile terminals within the service area covered by each base station radio device. In a mobile communication system in which one call channel is assigned to a base station radio device every time a call from the mobile terminal occurs, a call response to a call request from the mobile terminal to the first candidate base station radio device If the mobile terminal does not return, the mobile terminal determines the next candidate base station radio apparatus as a neighboring station with a call response wait timeout, and transmits a call request to the determined next candidate base station radio apparatus. A communication system is known (see, for example, Patent Document 1).
JP 2003-224882 A

  However, according to the technique disclosed in Patent Document 1 described above, the mobile station notifies the mobile station of its own congestion state by not returning a call response within a response waiting time (timeout). In order to know the state of the base station, it is necessary to make a call first. Therefore, when there are many congested base stations, it takes time to complete the call connection and a waiting time is generated, which causes trouble for the user.

  The present invention has been made in view of the above circumstances, and under the circumstances described above, by constructing a mechanism that allows a mobile station to select and connect to an optimal base station for connection, it is possible to change from a call request to a connection. It is an object of the present invention to provide a mobile communication system, a mobile station apparatus, and an access control method that improve the service by shortening the time required.

  In order to solve the above-described problems, the present invention provides a mobile communication system in an environment in which service areas of a base station for a mobile station overlap, and means for detecting a congestion status in the own station, and the detected congestion A base station device comprising: means for determining a state according to at least one threshold to generate congestion determination information; means for transmitting the congestion determination information in broadcast information to a mobile station; and transmitting from a plurality of base station devices Means for receiving the broadcast information, means for determining a congestion state from the broadcast information according to at least one threshold, and means for calling the base station apparatus selected according to the determination result And a mobile station apparatus.

  Further, the present invention provides a mobile communication system in an environment where service areas of a base station for a mobile station overlap with each other, the means for detecting a congestion state in the own station, and the detected congestion state as at least one threshold value Base station apparatus comprising means for generating congestion determination information by determining according to the above, means for incorporating the congestion determination information into broadcast information and transmitting the information to a mobile station, and broadcast information transmitted from the plurality of base station apparatuses. A means for receiving, a means for determining at least one threshold according to a transmission capacity required by the own station, a congestion state obtained from the received broadcast information and the determined threshold are compared, and the requested transmission band of the own station And a mobile station device comprising means for selecting a base station that can be secured and making a call to the base station.

  The present invention is also a mobile communication system in which a centralized management station assigns different channels to the respective base stations in an environment where service areas of the base stations for the mobile stations overlap. Means for detecting a congestion state, means for determining the detected congestion state according to at least one predetermined threshold and generating congestion determination information, and means for incorporating the congestion determination information into broadcast information and transmitting the information to a mobile station A base station apparatus comprising: means for receiving the broadcast information transmitted from the plurality of base station apparatuses; means for determining a congestion state from the broadcast information according to at least one threshold; and selected according to the determination result An interference state from a mobile station device comprising means for making a call to a base station device and congestion determination information transmitted from the plurality of base station devices A central control station apparatus comprising: means for calculating a channel arrangement that minimizes the interference; and means for transmitting the channel allocation to instruct each of the base stations. It is characterized by.

  Further, the present invention provides a mobile station apparatus in an environment where service areas of the base station for the mobile station overlap, and is obtained by determining a congestion state detected in the base station according to at least one threshold value Means for receiving broadcast information incorporating determination information from each of the base stations; means for determining a congestion state from the received broadcast information according to at least one threshold; and a base station selected according to the determination result And means for making a call.

  Further, the present invention is an access control method in a mobile communication system in an environment where service areas of a base station for a mobile station overlap, and the base station apparatus detects a congestion state in the own station and detects the detected state. A step of generating congestion determination information by determining a congestion state according to at least one threshold, and transmitting the congestion determination information to broadcast information, and transmitting the information to a mobile station; Receiving the broadcast information, determining a congestion state from the broadcast information according to at least one threshold value, and making a call to a base station apparatus selected according to the determination result, To do.

  The present invention is also an access control method in a mobile station apparatus in an environment where service areas of the base station for the mobile station overlap, wherein the congestion state detected in the base station is determined according to at least one threshold value. Receiving the broadcast information incorporating the congestion determination information obtained from each of the base stations, determining the congestion state from the received broadcast information according to at least one threshold, and depending on the determination result Making a call to a selected base station.

  According to the present invention, the mobile station apparatus determines the congestion state from the broadcast information transmitted from the base station apparatus, and makes a call to the optimal base station based on the determination result, so the time required for connection can be shortened, Connection service can be improved. In addition, the mobile station apparatus has a reduced probability of connection rejection due to congestion. Furthermore, by using the transmission capacity and transmission speed, which are required loads, as the determination conditions, it is possible to establish a transmission path necessary for communication in advance and to perform communication, and it is possible to construct a good mobile communication system.

  FIG. 1 is a diagram showing an example of a connection configuration of a mobile communication system according to the present invention. In FIG. 1, reference numeral 1 is a mobile station (SS), reference numeral 2 is a base station (BS), and reference numeral 3 is a centralized management station (CS). A client PC (# 1 to # 6), an access point (A to D), and a centralized management server 5 are illustrated. The access point (A to D) and the central management server 5 are connected by a router 4. As is apparent from the figure, it can be seen that the service areas overlap and congestion occurs at the access points B, C, and D. Details will be described later.

  FIG. 2 is a base station apparatus, FIG. 3 is a mobile station apparatus, and FIG. 4 is a block diagram showing the expanded functions of the internal configuration of the centralized management station apparatus.

In FIG. 2, the base station apparatus (access points A to D) includes a congestion state detection unit 21, a threshold TBL22 (table), a congestion state determination unit 23, a congestion state information incorporation unit 24, and a broadcast information generation unit 25. And a notification information transmission unit 26.
The congestion state detection unit 21 has a function of detecting the congestion state in the own station, and the congestion state detected here is supplied to the congestion state determination unit 23. The congestion state determination unit 23 is also supplied with threshold data from the threshold value TBL22, and is compared with the detected congestion state. As a result of the determination, the congestion state is supplied to the congestion state information incorporation unit 24 as load information. To do. On the other hand, the broadcast information generation unit 25 embeds load information (load indicator) supplied via the congestion state information incorporation unit 24 in known broadcast information including a base station ID and the like via the broadcast information transmission unit 26. Transmit to mobile station apparatuses (client PCs # 1 to # 6). FIG. 5 shows an example of the frame structure of the broadcast information described above.

In FIG. 3, the mobile station apparatus (client PCs # 1 to # 6) includes a plurality of broadcast information reception units 11, a congestion state determination unit 12, a threshold value TBL13, a threshold value determination unit 14, and a connection destination base station determination unit. 15 and a call control unit 16.
The broadcast information receiving unit 11 has a function of receiving broadcast information transmitted from a plurality of base station apparatuses (access points A to D), and the broadcast information received here is supplied to the congestion state determination unit 12. On the other hand, the threshold value determination unit 14 has a function of determining at least one threshold value according to a required load such as a transmission capacity or a transmission speed required by the own station, and the threshold value determined here is stored in the threshold value TBL13. Further, the congestion state determination unit 12 compares the load information obtained from the broadcast information received via the broadcast information reception unit 11 with the requested load, and supplies the result to the connection destination base station determination unit 15. The connection destination base station determination unit 15 selects a base station (access points A to D) that can secure the requested transmission band of the local station based on the output from the congestion determination unit 12 and activates the call control unit 16. Have. The call control unit 16 has a function of calling a selected base station.

In FIG. 4, the centralized management station apparatus (centralized management server 5) includes a plurality of base station list reception units 31, an area interference map creation unit 32, a load allocation control unit 33, a frequency allocation control unit 34, an area instruction. The transmitter 35 is configured.
The base station list receiving unit 31 has a function of receiving a receivable base station list transmitted from a plurality of base station devices (access points A to D), and the received list is supplied to the area interference map creating unit 32 Is done. The area interference map creation unit 32 creates an area interference map indicating an interference state between base stations from a list of receivable base stations transmitted from a plurality of base station devices (access points A to D), and a load allocation control unit 33 And supplied to the frequency allocation control unit 34. The load allocation control unit 33 and the frequency allocation control unit 34 grasp the interference state between the base stations from the information created by the area interference map creation unit 32, and the load allocation control unit 33 selects the base station optimal for the required load. The frequency allocation control unit 34 performs calculation for allocating an optimum channel to each base station. The load information and frequency information calculated and obtained here are transmitted to each base station (access points A to D) via the area instruction transmission unit 35.

FIGS. 6 to 8 are both cited for explaining the operation of the embodiment of the present invention. The concept of load assignment and frequency assignment control (FIG. 6), connection procedure 1 (FIG. 7), and connection procedure, respectively. Each of 2 (FIG. 8) is shown.
Hereinafter, the operation of the embodiment of the present invention shown in FIGS. 1 to 5 will be described in detail with reference to FIGS.

In FIG. 6, (a) shows an example of load assignment, and (b) shows an example of frequency assignment. In FIG. 6A, in the left frame, there is no mobile station under the base station A, the mobile station # 2 under the base station B, and the mobile stations # 1, # 3 under the base station C. , # 4, and # 5 are examples in which the mobile station # 6 exists under the base station D.
In this state, the load is concentrated on the base station C, so it is necessary to achieve load distribution as shown in the right frame. Specifically, since the mobile station # 3 is under the control of both the base station B and the base station C, the mobile station # 3 is controlled so as to be connected to the base station B. Control is performed so that mobile station # 5 is connected to base station D, leaving # 4. As a result, two base stations are accommodated and distributed. In the present invention, the above-described control is performed by broadcast information transmitted from the base station (access points A to D) or by controlling the base station (access points A to D) from the central management station device (central management server 5). It is something to execute.

After performing load distribution control as described above, frequency allocation control is performed according to the amount of traffic each has. Frequency allocation control is performed by the centralized management station device (centralized management server 5), which notifies the base station (access points A to D) and reconfigures the service area. This is shown in FIG. 6 (b).
That is, if the traffic volume of the base stations B, C, and D is the same, for example, when the required rate is low, for example, the frequency f1 is allocated, and the frequency resources can be effectively used by sharing them in time. Further, when the amount of information increases, another frequency f2 is allocated, and when the amount of information increases further, control is performed to allocate the frequencies f1, f2, and f3 to each. By controlling in this way, it is possible to assign one to three types of frequency resources depending on the information amount and transmission rate of what originally required three different frequency resources.

Hereinafter, the connection procedure will be described. In FIG. 7, first, the base station apparatus (BS2) transmits broadcast information (pilot channel) to each mobile station apparatus (SS1) (S71). Broadcast information is generated by the congestion state detection unit 21 detecting the congestion state in its own station, and the congestion state information incorporation unit 24 generating the load information determined by the congestion state determination unit 23, here “LOW”. It is executed by embedding in the broadcast information such as the base station ID generated by the unit 25 and transmitting it.
In the mobile station apparatus (SS1), broadcast information is also received from other base stations via the broadcast information receiving unit 11, and an accessible base station list is created from the plurality of broadcast information received here (S72). . Here, it is assumed that the base stations BS # 1, BS # 2, and BS # 3 are listed, and the load information is “LOW” for all of them.

  On the other hand, in the mobile station apparatus (SS1), the congestion state determination unit 12 calculates the required load (transmission capacity) (S73), and the connection destination base station determination unit 15 calculates the connection destination from the previous accessible base station list and the request load. A base station is determined (S74). Then, a call is made to the connection destination base station via the call control unit 16. The base station (BS) that received the call determines whether or not access is possible based on the load state of the magnetic pole and the required load of the mobile station such as the required transmission capacity, and permits or denies access (S75). When access is permitted, communication is started between the mobile station apparatus (SS1) and the base station apparatus (BS2).

FIG. 8 shows a case where the mobile station device SS1 makes a call request to the base station device BS # 1 (2), the connection is temporarily refused, and the call request is transmitted to another base station device BS # 2 (2). It is the figure which showed the connection procedure of.
The difference from the example shown in FIG. 7 is that the load information incorporated in the broadcast information transmitted from the base station apparatus BS # 1 (2) is “HIGH”, and the mobile station apparatus (SS1) that has received this information. Is determined to be unable to satisfy the requested load calculated in the own station, and the other base station device BS # 2 listed in the created accessible base station list is called (S84). In the base station BS # 2 that has received the call request, access is permitted or denied by determining whether or not access is possible based on the load state of the magnetic pole and the requested load of the mobile station such as the requested transmission capacity. Communication is started between SS1 and BS2.
Note that the threshold check by the congestion state determination unit 23 in the base station apparatus (BS) and the threshold check by the congestion state determination unit 12 in the mobile station apparatus (SS) are not limited to one threshold, and are described above. The transmission capacity and transmission speed are checked in multiple stages.

  As described above, according to the present invention, in an environment where service areas of a plurality of base stations overlap, the longer the number of accessible base stations, the longer the time required for connection in connection rejection due to timeout of a conventional connection request. However, since the mobile station apparatus selects and connects an optimal base station in advance, connection can be made in a short time from a call request. Similarly, the probability of connection refusal due to congestion is reduced, and similarly, the transmission path necessary for communication is secured in advance by using the transmission capacity and transmission speed required by the mobile station as connection judgment conditions. Thus, a good mobile communication system can be constructed.

It is a figure which shows an example of the connection structure of the mobile communication system in this invention. It is the block diagram which expanded the function and showed the internal structure of the mobile station apparatus concerning embodiment of this invention. It is the block diagram which expanded the function and showed the internal structure of the base station apparatus concerning embodiment of this invention. It is the block diagram which expanded the function and showed the internal structure of the centralized management station apparatus concerning embodiment of this invention. It is a figure which shows an example of the flame | frame structure of the alerting | reporting information concerning embodiment of this invention. It is a figure which shows the concept of load allocation and frequency allocation control concerning embodiment of this invention. It is a figure which shows an example of the connection procedure concerning embodiment of this invention. It is a figure which shows the other example of the connection procedure concerning embodiment of this invention. It is a figure which shows an example of a structure of the mobile communication system in the environment which constructed | assembled the service area with the pico cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mobile station (SS), 2 ... Base station (BS), 3 ... Central management station (CS), 4 ... Router, 5 ... Central management server (central management station apparatus), 11 ... Broadcast information receiving part, 12 ... Congestion state determination unit, 13 ... threshold TBL, 14 ... threshold determination unit, 15 ... destination base station determination unit, 16 ... call control unit, 21 ... congestion state detection unit, 22 ... threshold TBL, 23 ... congestion state determination unit , 24 ... congestion state information incorporation unit, 25 ... broadcast information generation unit, 26 ... broadcast information transmission unit, 31 ... base station list reception unit, 32 ... area interference map creation unit, 33 ... load allocation control unit, 34 ... frequency allocation Control unit, 35 ... area instruction transmission unit

Claims (6)

A mobile communication system in an environment where base station service areas for mobile stations overlap,
Means for detecting a congestion state in the own station, means for determining the detected congestion state according to at least one threshold and generating congestion determination information, means for incorporating the congestion determination information in broadcast information and transmitting the information to a mobile station A base station device comprising:
A means for receiving the broadcast information transmitted from the plurality of base station apparatuses; a means for determining a congestion state from the broadcast information according to at least one threshold; and a base station apparatus selected according to the determination result A mobile station device comprising means for calling
A mobile communication system comprising: A mobile communication system in an environment where base station service areas for mobile stations overlap,
Means for detecting a congestion situation in the own station, means for determining the detected congestion state according to at least one threshold and generating congestion determination information, means for transmitting the congestion determination information in broadcast information and transmitting the information to a mobile station A base station device comprising:
Means for receiving broadcast information transmitted from a plurality of base station apparatuses; means for determining at least one threshold according to a transmission capacity required by the own station; and a congestion state obtained from the received broadcast information and the determination A mobile station device comprising a means for selecting a base station that can secure the requested transmission band of the local station and making a call to the base station;
A mobile communication system comprising: A mobile communication system in which a centralized management station assigns different channels to the respective base stations in an environment where service areas of the base stations for the mobile stations overlap with each other,
Means for detecting the congestion status in the own station, means for determining the detected congestion state according to at least one predetermined threshold and generating congestion determination information, and transmitting the congestion determination information in broadcast information to the mobile station A base station device comprising means,
A means for receiving the broadcast information transmitted from the plurality of base station apparatuses; a means for determining a congestion state from the broadcast information according to at least one threshold; and a base station apparatus selected according to the determination result A mobile station device comprising means for calling
Means for determining an interference state from congestion determination information transmitted from a plurality of the base station devices, calculating a channel arrangement that minimizes the interference, and instructing the respective base stations to calculate the channel arrangement A centralized management station device comprising means for transmitting to
A mobile communication system comprising: A mobile station device in an environment where the base station service area for the mobile station overlaps,
Means for receiving from each of the base stations broadcast information incorporating congestion determination information obtained by determining the congestion state detected in the base station according to at least one threshold;
Means for determining a congestion state from the received broadcast information according to at least one threshold;
Means for calling a base station selected according to the determination result;
A mobile station apparatus in a mobile communication system, comprising: An access control method in a mobile communication system in an environment where base station service areas for mobile stations overlap,
In the base station device, the congestion status in the own station is detected, the detected congestion status is determined according to at least one threshold value to generate congestion determination information, and the congestion determination information is embedded in the broadcast information and transmitted to the mobile station Including steps,
In the mobile station device, the broadcast information transmitted from the plurality of base station devices is received, the congestion state is determined from the broadcast information according to at least one threshold, and the base station device selected according to the determination result An access control method in a mobile communication system comprising steps for making a call to a mobile communication system. An access control method in a mobile station apparatus in an environment where base station service areas for mobile stations overlap,
Receiving broadcast information incorporating congestion determination information obtained by determining a congestion state detected in the base station according to at least one threshold from each of the base stations;
Determining a congestion state from the received broadcast information according to at least one threshold;
Calling a base station selected according to the determination result;
An access control method in a mobile station apparatus characterized by comprising:

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