JP2003111133A - Mobile communication system and method of controlling its traffic - Google Patents

Mobile communication system and method of controlling its traffic

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Publication number
JP2003111133A
JP2003111133A JP2001295984A JP2001295984A JP2003111133A JP 2003111133 A JP2003111133 A JP 2003111133A JP 2001295984 A JP2001295984 A JP 2001295984A JP 2001295984 A JP2001295984 A JP 2001295984A JP 2003111133 A JP2003111133 A JP 2003111133A
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JP
Japan
Prior art keywords
base station
control
traffic
station
mobile
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2001295984A
Other languages
Japanese (ja)
Inventor
Narihira Takemura
Sunao Yamamoto
直 山本
成平 竹村
Original Assignee
Nec Microsystems Ltd
エヌイーシーマイクロシステム株式会社
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Publication date
Application filed by Nec Microsystems Ltd, エヌイーシーマイクロシステム株式会社 filed Critical Nec Microsystems Ltd
Priority to JP2001295984A priority Critical patent/JP2003111133A/en
Publication of JP2003111133A publication Critical patent/JP2003111133A/en
Pending legal-status Critical Current

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Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02DCLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THIR OWN ENERGY USE
    • Y02D70/00Techniques for reducing energy consumption in wireless communication networks

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of inexecutable communication when mobile stations are unevenly distributed. SOLUTION: The control zone CZi of a base station BSi which controls mobile stations 1 is divided into partial zones PZi1-PZij and the base station BSi collects the information on the numbers and states (busy, standby, power supply disconnected after location registration) of mobile stations respectively existing in the partial zones PZi1-PZij at every zone PZi1-PZij. An upper-rank control station 2 grasps the limit of traffic density of the base station BSi, by receiving communication traffic information from the station BSi and standardize the traffic of the station BSi based on the information. Consequently, the loss probability is reduced even when the mobile stations 1 are unevenly distributed in the control zone CZi.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system and a traffic control method therefor, and more particularly to a mobile communication system and a traffic control method therefor for reducing the incommunicable state when mobile stations are partially distributed. Regarding

[0002]

2. Description of the Related Art In general, the number of mobile stations and their communication traffic has increased steadily in recent years, when mobile communication systems represented by mobile phones and the like have become widespread. It is being appreciated.

On the other hand, in urban areas and the like, communication traffic may be explosively generated depending on the time zone, and the call loss rate in each control zone often becomes so large that it cannot be ignored.

Therefore, at present, for example, JP-A-6-1017 is used.
As described in Japanese Patent Laid-Open No. 01-101, a directional antenna device capable of varying output electric field strength in an arbitrary direction at a plurality of levels is provided for each base station, and each base station is provided with a directional antenna device. A method and means for suppressing the call loss rate as low as possible by adjusting the antenna device and changing the control zone so that the call loss rate of each base station can be equalized are adopted.

However, in such conventional methods and means, the current position of the mobile station is specified only in units of control zones of each base station, and only the potential traffic density between adjacent base stations is compared. Therefore, when the mobile stations are unevenly distributed in a part of the zone, there is a situation in which the actual call loss ratio cannot be leveled.

FIGS. 8 (a) and 8 (b) are a system configuration diagram before control and a system configuration diagram after control in a traffic control for explaining an example of the related art, respectively. Figure 8
As shown in (a), for example, four radio base stations BS1 to BS1
When the system is configured by BS4, the area where each radio base station is responsible for controlling the mobile station is defined as the control zone C.
In the system before control, it is assumed that the centralized zone 4a of the mobile station exists in the control zone CZ2.

In order to alleviate the traffic in the mobile station central zone 4a existing in the control zone CZ2, conventionally,
It is controlled by a control method of equal burden on adjacent zones. That is, as shown in FIG. 8 (b), when the mobile station central zone 4a exists in the control zone CZ2, it is assumed that the mobile stations are evenly present in the entire control zone CZ2, and the adjacent base stations BS1, BS1. Control is carried out by trying to share evenly from BS3 and BS4. As a result, although the mobile station central zone 4a is reduced in the control zone CZ2, the base station BS3 bears most of it, and this time, the base station BS3 needs to be controlled.

9 (a) and 9 (b) are a system configuration diagram before control and a system configuration diagram after control, respectively, for explaining another conventional example. Figure 9
As shown in (a), it is assumed that the mobile station central zone 4b occurs in a plurality of control zones CZ2, CZ4 before traffic control.

Also at this time, as shown in FIG. 9B, control is performed between the base stations BS2 and BS4 and the adjacent base station only by comparing the potential traffic density according to the information before the output change. . For this reason, the base station BS3 bears a large burden on the mobile station central zone 4b of both the base station BS2 and the base station BS4. Therefore, also in this case, the concentration is eased in the control zones CZ2 and CZ4, but the base station BS3 exceeds the control limit.

[0010]

In the above-mentioned conventional mobile communication system and its traffic control method, when the mobile stations are unevenly distributed in a part, the control zone in which the mobile station concentrated zone exists Although the degree of concentration can be relaxed, there is a drawback that traffic congestion occurs in any control zone and a communication-disabled state occurs in any control zone.

An object of the present invention is to provide a mobile communication system and a traffic control method therefor capable of reducing the incommunicable state even when the mobile stations are partially distributed.

[0012]

A mobile communication system of the present invention divides a control zone capable of supporting a mobile station into a plurality of part zones and controls the base stations; And a higher-order control station that collects communication traffic information in part zone units, the higher-order control station, based on the communication traffic information, so that the call loss rate between the plurality of base stations and the mobile station is minimized,
It comprises a means for supplying control information for adjusting the communication support range of each part zone unit to each of the plurality of base stations.

Further, each of the plurality of base stations according to the present invention measures the output electric field strength of the mobile station in units of the part zones to determine which base station and which part zone the mobile station is located in. Is formed.

Further, each of the plurality of base stations in the present invention can change the output electric field strength as a means for supplying control information for adjusting the communication support range of the part zone unit. It is formed by including a plurality of antenna devices.

Further, each of the plurality of base stations in the present invention comprises means for collecting communication traffic information between the base station and the mobile station in units of the part zones and transmitting the information to the upper control station. Formed.

Further, the upper control station in the present invention is
It is formed by including means for controlling the communication support range of each of the plurality of base stations as a group.

Further, the upper control station in the present invention is
Receiving communication traffic information between the base station and the mobile station in the part zone unit from each of the plurality of base stations, and to reduce the call loss rate in the base station unit, each base for each base station It is formed with means for issuing commands to adjust the radio coverage of the station.

The upper control station according to the present invention is
As the communication traffic information, by collecting each information of the number of mobile stations in use, the number of mobile stations in reception standby and the number of mobile stations in power off after position registration from the plurality of base stations, and weighting each state, It is formed by including means for calculating an output electric field strength required for each part zone unit so as to reduce the call loss rate for each base station unit.

Further, a traffic control method for a mobile communication system according to the present invention comprises: a plurality of base stations for dividing a control zone capable of supporting a mobile station into a plurality of part zones for control; An upper control station that collects communication traffic information in units of part zones, and the upper control station stores a control zone number, a part zone number, and mobile station status data given to each mobile station whose position is registered. The first storage means and the second storage means for storing the traffic amount information capable of controlling each base station, the part zone information of each base station, and the base station position information are provided, and the call loss rate of each base station is calculated. At the time of reduction, in calculating the output electric field strength required for each part zone unit, the traffic information collecting process and the trough are processed using the first and second storage means. Configured to perform click control process.

The upper control station according to the present invention is
The traffic information collecting process and the traffic control process are formed to be performed at arbitrary timings.

In the traffic information collecting process of the present invention, a search step for sequentially searching the communication traffic information of each base station, and the communication traffic information for each part zone is extracted based on the search result of the search step. Extraction step, and then, for each part zone, the number of mobile stations whose position is registered but currently powered off, the number of mobile stations that are powered on and in standby, and the number of mobile stations currently in use. And a counting step of counting the number of mobile stations.

In the traffic control process of the present invention, the potential traffic density of each base station is searched,
When a base station that needs to be shared is found in the limit search step for obtaining the limit of the potential traffic density that can tolerate the call loss rate, and when a base station that needs sharing is found in the limit search step, between each base station and a base station adjacent to that part zone, And a traffic leveling process step of leveling the traffic of the entire base station and outputting an output control signal from the upper control station to each base station. Is formed by.

In the traffic leveling process of the present invention, a search step of searching for a base station requiring control after initializing a search counter for a base station requiring control, and the control in the search step are performed. When there is no required base station, the processing is terminated depending on whether or not there is a change in the sharing of traffic, or while returning to the search step, when there is a base station that needs to be controlled in the search step, the search counter of the peripheral base station is initialized. , A search for peripheral base stations that can be shared, a determination step for determining the number of base stations that can be shared, and a data update step for updating the potential traffic density data by determining the share up to the shareable limit based on the result of the determination step. And updating the search counter of the base station requiring the control after the data updating step and repeating the searching step. It is formed in the Suyo.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION In the traffic control of a mobile communication system, the present invention further recognizes a range (control zone) controlled by each base station by further dividing into a plurality of ranges (part zones), For each part zone, the number of mobile stations existing inside the part zone and any of the states of "in use", "standby for reception", and "power off after location registration" for each mobile station (hereinafter, These pieces of information are collectively referred to as communication traffic information), and the communication traffic information is received from a base station and a plurality of base station groups, and the traffic volume of each base station is leveled based on the information. By having a higher-level control station with a control function, even if mobile stations in the control zone are unevenly distributed in a part without adding a base station, Traffic is to reduce the rate (call loss probability) of and the mobile station exceeds the control capabilities of the base station is incommunicable state.

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 (a) and 1 (b) are respectively a block diagram showing the outline of a communication system and a block diagram of its control zone for explaining an embodiment of the present invention. Figure 1
As shown in (a) and (b), the present embodiment is a radio base station BS that manages and controls a plurality of mobile stations 1, respectively.
1 to BSi and an upper control station 2 that controls these wireless base stations BS1 to BSi, and the upper control station 2 stores a memory 3 that stores information given to each mobile device whose position is registered, And storage means for storing information of each radio base station.

First, the radio base station BSi (i: arbitrary number)
Has a directional antenna device capable of varying the output electric field strength in an arbitrary direction at a plurality of levels, and manages the control zone CZi by dividing it into a plurality of part zones PZi1 to PZij. In addition, the mobile station 1 represented here is in the control zone CZi and is under the control of the base station BSi. The base station BSi collects communication traffic information of the mobile station 1 for each of the part zones PZi1 to PZij, and the collected information is handed over to the host control station 2 and stored in the memory 3.

On the other hand, the upper control station 2 has controllable traffic amount information Fi of each base station BS1 to BSi under its control, part zone information of each base station, and base station position information, and is stored in the memory 3. Based on the potential traffic density calculated from the communication traffic information (control zone number, part zone number, mobile station state data), there is a possibility that the controllable traffic volume of the base station may exceed the potential traffic density of adjacent base stations. Adjust the output of the directional antenna with a low base station and change the control zone to reduce the call loss rate. At this time, the change ratio is calculated based on the potential traffic density of each part zone, and the upper control station 2 comprehensively judges a plurality of base station information, whereby the mobile stations are unevenly distributed in the control zone. Also try to reduce the blocking rate more accurately.

In short, in a mobile communication system composed of a plurality of mobile units, base stations, and a host control station for controlling the plurality of mobile units, each base station can direct the output electric field strength in an arbitrary direction at a plurality of levels. It has a plurality of characteristic antennas, and has means for dividing and managing its own control zone into a plurality of part zones, collecting communication traffic information for each part zone, and transmitting it to the upper control station 2. This upper control station 2 stores communication traffic information from a plurality of base stations in a memory 3, and calculates the controllable traffic amount of each base station and the potential traffic density for each base station and for each part zone calculated from the communication traffic information. On the basis of,
It has a function of designating the output electric field strength of each directional antenna to each base station so as to reduce the call loss rate.

At this time, the upper control station collects each piece of information in a support area (group) consisting of a plurality of base stations, that is, in units of groups, and investigates traffic. The output of can be adjusted.

FIG. 2 is a process flow chart for collecting the communication traffic information in FIG. As shown in FIG. 2, in periodically updating the data for obtaining the potential traffic density, the higher-level control station 2 manages the communication traffic information collection processing configured by hardware or software or a mixed system thereof. It is executed at regular intervals.

First, processing steps S100 to S103
In step S115, the communication traffic information of each base station in the memory 3 managed by the upper control station 2 is sequentially searched. Then, after extracting communication traffic information for each part zone in processing steps S104 to S109 and S114, S111 to S116 to S12.
By 0, the number of mobile stations Rij whose position is registered but the power is currently turned off for each part zone, and the number of mobile stations Pij which are turned on and are in a standby state,
The number of mobile stations currently in use Bij is counted. Also,
The search counter initialization step S110 is a pointer for recollecting the information of the base station. That is, this search counter is for specifying each base station under the control of the upper control station 2, and each counter corresponds to each base station. In short, SORI steps S110 to S1
The counter as a pointer is incremented between 20 and the information of the corresponding base station is collected. Further, the potential traffic density Dij in the part zone is calculated in the processing step S112 from the count result, and the potential traffic density Di of the entire base station is calculated in the processing step S113. At this time, the potential traffic density Dij of a certain part zone PZj of an arbitrary base station BSi is expressed by the following equation (1). In addition,
a, b, and c are proportional constants.

Dij = aRij + bPij + cBij (1) Further, the potential traffic density Di of the entire base station is expressed by the following equation (2). IjMAX is the base station BS
This is the maximum number of part zones i has.

Di = Di1 + Di2 + ... + DijMAX (2) Next, search for communication traffic information of each base station described above, extraction of communication traffic information for each part zone,
Counting the number of mobile stations in various states will be described in detail.

First, in searching the communication traffic information of each base station, when the upper control station 2 is periodically activated, the base station number i under management is initialized by the base station initialization step S100. Then, it is determined in the search end determination step S101 whether or not all the searches have been completed. Here, when the entire search is completed, the processing is ended, but when the entire search is not completed, the potential traffic Di of the base station i is initialized in the potential traffic initialization step S102. Further, after the potential traffic initialization step S102, it is determined whether or not the base station i is under the control by the base station control determination step S103, and if not, the processing step S115.
In step S, the managed base station number i is updated, and processing step S
Return to 101. As a result, the communication traffic information of each base station is searched, that is, the validity of the base station i is checked.

Next, in extracting the communication traffic information for each part zone, the above-mentioned processing step S1 is performed.
Since the base station i is under control in 03, the part zone number i of the base station i is initialized in the part zone number initialization step S104. Further, in the all part zone search determination step S105, it is determined whether the search of all the part zones of the base station i is completed,
When all the searches are completed, the managed base station number i is processed in processing step S115 as in processing step S103.
Is updated, and the process returns to step S101. On the other hand, when all the searches in the processing step S105 have not been completed, in the initialization step S106, the number of mobile stations Rij only for location registration of the base station i with respect to the part zone j is initialized, and then in the initialization step S107, The number of powered-on mobile stations Pij for part zone j of i is initialized, and, in initialization step S108, the number Bij of mobile stations in use for part zone j of base station i is used.
To initialize. After sequentially initializing the number of mobile stations, in order to check the validity of the part zone j, it is judged in the judgment step S109 whether or not the part zone j exists in the base station i.

Here, when the part zone j does not exist in the base station i, the potential traffic density Di of the base station i for the part zone j is calculated in the calculation step S112.
After calculating j and adding it to the potential traffic Di of the base station i in the adding step S113, the updating step S1
14 updates the part zone number j of the base station i,
The process returns to the all part zone search determination step S105 to repeat the process.

When the part zone j exists in the base station i in the judgment step S109, the mobile station search counter is initialized in the initialization step S110. As a result, the communication traffic information for each part zone is extracted.

Next, in counting the number of mobile stations in various states, after the mobile station search counter is initialized in the initialization step S110, the mobile station information is searched in the location registration information search step S111. . At this time, if the information is completed, the above calculation, addition,
Each of the updating steps S112 to S114 is performed, but when there is information in the information searching step S111, the registration state of the mobile station is determined in the state determining step S116. When the registration state of the mobile station is determined in this state determination step S116, if only the location registration is performed, the number of mobile stations Rij is added only for the location registration for the part zone j of the base station i in the addition step of S117, and If the power is on, the power-on number of mobile stations Pij for the part zone j of the base station i is added in the addition step of S118, and if the mobile station is in use, the addition of the base station i is performed in the addition step of S119. The number of mobile stations in use Bij for part zone j is added. When these addition steps S117 to S119 are completed, the search counter is updated in the update step S120, and then the process returns to the position registration information search step S111 to repeat the processing.

The above is the search of the traffic information shown in FIG.
It is a specific processing flow operation for extracting communication traffic information for each part zone and counting the number of mobile stations in each state.

FIG. 3 is a flow chart of the traffic control process in FIG. As shown in FIG. 3, in order to reduce the call loss rate by changing the output electric field strength of each base station BSi from the potential traffic density obtained in the processing flow of FIG. Alternatively, it is a traffic control processing flow configured by a mixed system thereof. This process is managed by the upper control station 2 and is executed at the same time as the communication traffic information collection process flow shown in FIG.

That is, processing steps S200 to S2
02 and S207, the potential traffic density Di of all the base stations managed by the upper base station 2 is searched, and the potential traffic density limit Di at which the call loss rate can be considered to be acceptable
Check to see if it is above TH. In any base station BSi, the potential traffic density limit DiTH at which the call loss rate can be considered to be acceptable is expressed by the following equation (3), where Fi is the traffic volume that the base station BSi can control. Note that e is a proportional constant.

DiTH = eFi (3) Potential traffic density D at any base station BSi
If i exceeds the potential traffic density limit DiTH,
It can be said that the base station BSi needs to share the traffic with other base stations. If a base station BSi that needs to share this traffic is found, further processing step S
From 203 to S206, each part zone PZij
For each, it is calculated how much traffic can be shared with the base station BSn adjacent to the part zone. Moreover, the shareable traffic volume TRij is expressed by the following formula (4) or formula (5) Dn-DnTH = (base station BSn can share, where Zn is the area ratio of the part zone PZij that the base station BSn can share. Maximum potential traffic density) (4) Zn × Dij = (potential traffic density when the base station BSn shares the maximum part zone PZij) (5) It can be said that it is a smaller value. After collecting this information for all the base stations under control, pattern recognition or data calculation based on the information collected in processing step S208 allows each antenna to appropriately share the potential traffic amount of all base stations. The output electric field strength is obtained, and an output control signal is transmitted to the base station that needs control in processing step S209.

Next, the calculation of the limit of the potential traffic density that can tolerate the above-mentioned call loss rate, the traffic sharing, and the traffic leveling will be described in detail.

First, in the calculation of the potential traffic density limit, when it is periodically activated, in the initialization step S200, all base station numbers i managed by the upper control station 2 are initialized, and then the search end determination step. S20
In step 1, it is determined whether the search for all management base stations has been completed. Here, when all the searches have not been completed, it is determined in the traffic leveling standard determination step S202 whether or not the potential traffic density Di of the base station i exceeds the traffic leveling standard DiTH of the base station i. If not, the managed base station number i is updated in the updating step S207 and the process returns to step S201.

On the other hand, in the calculation of the traffic sharing, when the standard is exceeded in step S202, the part zone j of the base station i is initialized in the initialization step S203. Then, in a search end determination step S204, it is determined whether or not the search of all part zones of the base station i is completed, and when the entire search is completed, that is, when the maximum value is exceeded, the above-described update step S2.
Similar update processing is performed in 07, but when all searches are not completed, that is, the maximum value is not exceeded, in step S205 of calculation and recording, the allocatable traffic density TRij for the part zone j of the base station i is calculated and recorded. .
When the allocatable traffic density TRij is calculated, the part zone j of the base station i is updated in the updating step S206, and the search end determining step S204 is repeated.

Next, in traffic leveling,
When all the searches are completed in the search end determination step S201 described above, that is, when the maximum value is exceeded, traffic leveling of all managed base stations is performed in the traffic leveling step S208, and the higher level control station 2 sends the traffic levels in the transmission step S209. An output control signal is transmitted to each base station. This completes the traffic leveling process.

FIG. 4 is a pattern diagram showing a first specific example of the traffic leveling process in FIG. As shown in FIG. 4, here, a pattern of four adjacent base stations is shown, and an example by pattern recognition is shown among the determination methods in the processing step S208 (traffic leveling of the entire base station) of FIG. 3 described above. Is. The solid arrows (→) of the patterns 1, 2, ..., Pattern 112, ..., Pattern 562, ... In this example represent the primary sharing, and the sharing should be performed preferentially as much as possible.
Further, a dotted arrow (--->) represents the secondary sharing, and is the sharing that should be performed when the primary correction cannot complete the allocation.

When the upper control station 2 controls four adjacent base stations, the potential traffic density can be controlled by the pattern in which the base stations under control are adjacent to each other, that is, "1-3 in pattern 1". "1-4""2-
4 "" 2-5 "" 2-6 "" 3-1 "" 3-2 "" 3-
There are only 10 part zones of "3", "4-1", and "4-6". Assuming that there are two states of control necessity / unnecessity for each of these 10 part zones, assuming a combination of possible part zone states, it can be seen that there are 2 10 = 1024. .
Appropriate control can be obtained by preparing the control pattern data in advance, such as patterns 1 to 562, for all these combinations.

FIGS. 5 (a) to 5 (c) are block diagrams showing the outline of a communication system for explaining a first concrete example of traffic control according to the present invention and a partially enlarged structure of a control zone thereof before control. It is a figure and the block diagram after control. Hereinafter, the first specific example will be described with reference to FIGS. 1 to 4 and 5 described above. Here, it is assumed that the upper control station 2 of FIG. 1 controls the base station group as shown in FIG. Further, it is assumed that the potential traffic density of the base station BS2 is at a level requiring control, but normally the mobile stations 1 are not evenly present in the control zone CZ, and people such as office buildings, department stores, and condominiums are crowded. Since it is assumed that the elements to be distributed are unevenly distributed in a part,
As shown in the enlarged view of (b), the mobile station central zone 4 is defined.

First, in order to recognize the control zone CZ2 by dividing it into a plurality of part zones PZ21 to PZ26, the communication traffic information collection processing flow of FIG. 2 is executed by periodic activation in the state of FIG. 5 (a). And the potential traffic density of the part zone PZ25 is very high, the part zones PZ24 and PZ26 are medium, the other part zones PZ21 to PZ23 of the base station BS2 and the base station BS.
The data that the potential traffic densities of 1, BS3 and BS4 are very small are extracted.

In this embodiment, the potential traffic density limit of each of the base stations BS1 to BS4 is set to 100, and the potential traffic density of the part zone PZ25 is set to 150 with respect to the execution result of the communication traffic information collection processing flow of FIG.
The potential traffic density of the part zones PZ24 and PZ26 is 100, and the other part zones PZ21 to PZ2
3 potential traffic density 0, base stations BS1, BS
3 and the potential traffic density of BS4 is defined as 10.
When the traffic control processing flow of FIG. 3 is carried out with the above information, processing step S202 of FIG.
The base station BS2 has a potential traffic density of 350
(100 + 100 + 150), the potential traffic density limit is 100, so it is determined that control is required. In subsequent process steps S204, S205, and S206, the shareable potential traffic densities of the part zones PZ24, PZ25, and PZ26 are calculated to be shareable by 90 based on the above equations (4) and (5). Since there is no other base station that needs to be controlled, the output radio wave intensity of each base station whose potential traffic density is leveled is determined based on the example of the pattern 112 of FIG. 4 in processing step S208 based on the above information. Then, in processing step S209, a control signal is transmitted to each base station.
As a result, the control zone of each base station is the pattern 1 of FIG.
As shown in FIG. 5C, each base station shares the mobile station concentrated band 4 as shown in FIG.

FIGS. 6A and 6B are a system configuration diagram before control and a system configuration diagram after control, respectively, for explaining a second specific example of traffic control according to the present invention. As shown in FIG. 6A, the above-mentioned FIG.
This is a case of controlling the base station having the same arrangement as that of, but the base stations that need to be controlled are two stations BS2 and BS4, and the mobile station central zone 4 is also wide.

Also in this embodiment, each control zone CZ
Since the potential traffic density information is obtained for each part zone in CZ4 and CZ4, the host control station 2 can determine which part zone should be shared to effectively share the potential traffic density. here,
The base station BS3 can share the potential traffic densities of both the base stations BS2 and BS4, but in the processing step S208 of FIG. 3 described above, if both are shared, the shareable upper limit D3TH of the base station BS3 will be exceeded. Whether or not there is also can be judged as a condition. If it is concluded that if both are shared, it will exceed the allocatable upper limit.
This is dealt with according to the example of the pattern 562 in FIG. 4 described above.
That is, it is determined that the base station BS2 and the base station BS4 are mainly shared by the base station BS1 and the base station BS3, respectively, and output to change the control range as shown in FIG. 6B. Send a control signal.

The above-described embodiment solves the potential traffic density leveling process for the entire base station in process step S208 of FIG. 3 by preparing pattern data as shown in FIG. 4 in advance. However, the same effect can be obtained in the data calculation based on the collected information. Hereinafter, this method will be described as another embodiment.

FIG. 7 is a traffic leveling processing flow chart for explaining another embodiment of the present invention. As shown in FIG. 7, the present embodiment obtains the same effect by data calculation based on the collected information, and is an example of a processing flow configured by hardware or software or a mixed system thereof. .

In this case, first, processing steps S300 and S
Through 301 and processing step S307, information about a base station having high potential traffic density and requiring control is retrieved. Then, process steps S302 to S3
In 04 and S308, base stations capable of sharing the potential traffic density are extracted from among the base stations existing in the vicinity of the searched base station requiring control, and the base stations to be shared are selected. Furthermore, processing steps S305 to S3
By 06 and processing step S309, the potential traffic density after the sharing is calculated, and the data is updated. By repeating these processes until there is no room for performing the potential traffic density control in processing step S310, the potential traffic density can be leveled.

In this traffic leveling process, a search counter (not shown) for a base station that needs control is initialized (S300), and a search is performed to determine whether there is a base station that needs control (S301). . Here, if there is no control-needed base station, it is judged whether or not there is a change in traffic sharing (S310), and if there is no change, the processing ends, but if there is a change, initialization of the search counter is repeated. Yes.

Next, in the search determination step S301, if there is a base station that needs to be controlled, the search counter of the peripheral base stations is initialized (S302), and then the peripheral base stations that can be shared are searched (S303). Then, the number of allocatable base stations is determined based on the result (S304). Here, when the number of allocatable base stations is more than one, only one base station is extracted as the allotment target base station (S308).

Further, when the number of allocatable base stations is specified to be one in the number of base stations determining step S304, the allocatable limit is allotted (S305). Similarly, when only one base station is extracted in processing step S308, only the corresponding base station is allowed to share the shareable limit (S309). These processing steps S30
5, in S309, when the sharing to the limit is decided,
Update the potential traffic density data (S30
6).

Thereafter, the search counter of the base station requiring control is updated (S307), and when the update is completed, the determination of the presence or absence of the base station requiring control is repeated again (S30).
1) Regularly perform traffic leveling processing.

Although the two embodiments have been described above, various modifications can be made in addition to these, which will be described below.

Firstly, a method of changing "a, b, c" included in the equation (1) described in the embodiment from a constant to a variable can be considered. That is, the movement of the mobile station 1,
When considering the ubiquitous pattern and its usage,
It is conceivable that the state will change significantly depending on the time of day, the day of the week, the date, etc. Therefore, by weighting “a, b, c” in the equation (1) according to the time, day of the week, day, etc. (variable treatment), a more appropriate response can be achieved.

For example, on weekday mornings, many mobile stations move from the residential area to the business district in a short time, and it is unlikely that the mobile stations still existing in the residential area will be used there. Is assumed. In such a case, the potential traffic density of the base station that controls the residential area is set to be low, and the potential traffic density of the base station that controls the business district is set to be high, and “a, b, c” are set as “variables”. By doing so, it is possible to support the traffic in the business district earlier, and it is possible to respond to the movement of the mobile station in a short time.

As a second method, a method of switching the periodic activation to the dynamic activation described in the embodiment can be considered.
In the above-described one embodiment, the processing flow of FIGS. 2 and 3 is described as “periodic activation” that is performed at regular time intervals. However, similar to the above modification, the situation may be changed depending on time, day of the week, date, etc. Therefore, it is possible that the control will always be performed for a certain period of time, so in some cases the state of the mobile station may change rapidly, but the time to execute the process is too long. May not be able to cope with the state change, and in other cases, the useless process may be repeated even though the state change does not occur. Therefore, the start cycle of FIG. 2 and FIG.
A more appropriate response can be realized by changing the date and time.

Further, in the third embodiment, it is possible that the processing of FIGS. 2 and 3 is not executed at an appropriate timing due to the activation cycle or the like. That is, even in the above modification, it is not possible to deal with the sudden occurrence of traffic due to an unexpected event. Therefore, when the position registration data of the currently existing part zone of the mobile station registered in the memory 3 of FIG. 1 changes by an arbitrary constant, the processes of FIGS. 2 and 3 are directly executed. It may be possible to provide various functions. In that case, no matter what timing the potential traffic density changes, appropriate measures can be taken.

[0067]

As described above, according to the mobile communication system and the traffic control method thereof of the present invention, the base station control zone is divided into a plurality of part zones for management, and the upper control station controls the plurality of base stations. By performing comprehensive management, it is appropriate to divert the existing mobile communication system without adding a large load such as adding a base station and reduce the call loss rate even if the mobile stations are unevenly distributed in the base station control zone. This has the effect of enabling various controls.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a communication system and a configuration of a control zone thereof for explaining an embodiment of the present invention.

FIG. 2 is a process flow chart for collecting communication traffic information in FIG.

FIG. 3 is a flow chart of traffic control processing in FIG.

FIG. 4 is a pattern diagram showing a first specific example of the traffic leveling process in FIG.

FIG. 5 is a diagram showing a state before control, a partial enlargement thereof, and after control for explaining a first specific example of traffic control according to the present invention.

FIG. 6 is a diagram showing states before and after control for explaining a second specific example of traffic control according to the present invention.

FIG. 7 is a traffic leveling process flow chart for explaining another embodiment of the present invention.

FIG. 8 is a diagram showing a system configuration before and after control in traffic control for explaining a conventional example.

FIG. 9 is a diagram showing a system configuration before and after control in traffic control for explaining another conventional example.

[Explanation of symbols]

1 mobile station 2 Upper control station 3 memory 4 mobile station concentrated zones BS1 to BSi wireless base stations CZ1-CZi control zone PZi1 to PZij part zone

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigehei Takemura             1-403 Kosugi-cho, Nakahara-ku, Kawasaki-shi, Kanagawa             53 NC Micro Systems Stock Association             In-house F term (reference) 5K019 AA01 BA45 BB21 EA01 EA16                 5K067 AA12 BB04 DD27 DD44 DD57                       EE02 EE10 EE16 EE46 EE55                       HH21 HH23 KK02 KK03 LL01                       LL05

Claims (12)

[Claims]
1. A plurality of base stations for controlling by dividing a control zone capable of supporting a mobile station into a plurality of part zones,
A higher control station that collects communication traffic information in units of part zones from the plurality of base stations, wherein the higher control station has a call loss rate between the plurality of base stations and the mobile station based on the communication traffic information. A mobile communication system comprising means for supplying control information for adjusting the communication support range of each part zone unit to each of the plurality of base stations so as to minimize
2. Each of the plurality of base stations measures the output electric field strength of the mobile station in units of the part zones to identify which base station and which part zone the mobile station is located in. The mobile communication system according to claim 1, further comprising means.
3. Each of the plurality of base stations, as a means for supplying control information for adjusting the communication support range of the part zone unit, one or a plurality of antennas capable of changing the output electric field strength. The mobile communication system according to claim 1, further comprising a device.
4. Each of the plurality of base stations comprises means for collecting communication traffic information between the base station and a mobile station in units of the part zone and transmitting the information to the upper control station. 1. The mobile communication system according to 1.
5. The mobile communication system according to claim 1, wherein the upper control station comprises means for controlling the communication support ranges of the plurality of base stations as a group.
6. The upper control station receives communication traffic information between the base station and the mobile station in the part zone unit from each of the plurality of base stations, and reduces the call loss rate in the base station unit. The mobile communication system according to claim 1, further comprising means for issuing an instruction to each of the base stations to adjust a radio support range of each base station.
7. The upper control station sends, as the communication traffic information, information on the number of mobile stations in use, the number of mobile stations in reception standby, and the number of mobile stations in power-off after position registration from the plurality of base stations. The mobile communication system according to claim 1, further comprising means for calculating an output electric field strength required for each part zone unit so as to reduce a call loss rate for each base station by collecting and weighting each state.
8. A plurality of base stations for controlling by controlling a control zone capable of supporting a mobile station by dividing the control zone into a plurality of part zones,
A higher control station that collects communication traffic information in units of part zones from the plurality of base stations, wherein the higher control station is given a control zone number, part zone number and A first storage unit for storing mobile station status data; and a second storage unit for storing controllable traffic amount information of each base station, part zone information of each base station, and base station position information. When calculating the output field strength required for each part zone unit when reducing the call loss rate for each base station unit, performing traffic information collection processing and traffic control processing using the first and second storage means. A traffic control method for a mobile communication system, comprising:
9. The traffic control method for a mobile communication system according to claim 8, wherein the upper control station carries out the traffic information collection processing and the traffic control processing at arbitrary timings.
10. The traffic information collecting process comprises a search step of sequentially searching communication traffic information of each base station, and an extraction step of extracting communication traffic information of each part zone based on a search result of the search step. , And then, for each part zone, the number of mobile stations whose location is registered but the power is currently turned off, the number of mobile stations that are powered on and in the standby state, and the number of mobile stations currently in use 9. The traffic control method for a mobile communication system according to claim 8, further comprising a counting step for counting and.
11. The traffic control process searches a potential traffic density of each base station to find a potential traffic density limit at which a call loss rate can be tolerated, and a base station that needs sharing is found in the limit searching step. Then, for each part zone, with a base station adjacent to the part zone, a calculation step of calculating how much traffic can be shared, and leveling the traffic of the entire base station, 9. The traffic control method for a mobile communication system according to claim 8, further comprising a traffic leveling processing step of outputting an output control signal from the upper control station to each base station.
12. In the traffic leveling process, a search step of searching for a base station requiring control after initializing a search counter for a base station requiring control, and a base requiring control in the search step. When there is no station, the processing is terminated depending on whether there is a change in the sharing of traffic, or while returning to the search step, when there is a base station that needs control in the search step, initialization and sharing of the search counter of peripheral base stations It includes a determination step of searching for possible peripheral base stations and determining the number of allocatable base stations, and a data updating step of updating the potential traffic density data by obtaining the allotment to the allocatable limit based on the result of the determination step. 12. The retrieving step is repeated after renewing the retrieval counter of the base station requiring the control after the data updating step. Traffic Control Method for Mobile Communication Systems in Japan.
JP2001295984A 2001-09-27 2001-09-27 Mobile communication system and method of controlling its traffic Pending JP2003111133A (en)

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