Mobile communication system and method of controlling its traffic

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a mobile communication system and a traffic control method thereof, and particularly to a mobile communication system and a traffic control method thereof that reduce a communication impossible state when mobile stations are partially distributed.

【0002】

[Conventional technology]

In general, mobile communication systems such as mobile phones have become widespread today, and the number of mobile stations and their communication traffic are steadily increasing, and base stations are being strengthened and expanded to cope with the increase.

【0003】

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

【0004】

Therefore, at present, for example, as described in Japanese Patent Application Laid-Open No. 6-101701, a directional antenna device capable of varying the output electric field strength in an arbitrary direction at a plurality of levels is provided for each base station, and the potential of each mobile station is present. By adjusting the antenna device of each base station according to the traffic density and changing the control zone so that the call loss rate of each base station can be leveled, a method and means for suppressing the call loss rate as low as possible are adopted.

【0005】

However, in such a conventional method or means, the current position of the mobile station is specified only for each control zone of each base station, and control is performed only by comparing the potential traffic densities between adjacent base stations. Therefore, when each mobile station is unevenly distributed in a part of the zone, there is a situation in which the call loss rate cannot be leveled according to the actual situation.

【0006】

8 (a) and 8 (b) are a system configuration diagram before control and a system configuration diagram after control in traffic control for explaining a conventional example, respectively. As shown in FIG. 8 (a), for example, when a system is composed of four radio base stations BS1 to BS4, the area in which each radio base station is in charge of controlling a mobile station is called a control zone CZ1 to CZ4. In the system before control, it is assumed that the mobile station concentration zone 4a exists especially in the control zone CZ2.

【0007】

In order to mitigate the traffic in the mobile station centralized zone 4a existing in this control zone CZ2, conventionally, control is performed by a control method called an equal burden on adjacent zones. That is, as shown in FIG. 8 (b), when the mobile station concentration 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 and BS1 Control by trying to share evenly from BS3 and BS4. As a result, the mobile station concentration zone 4a is reduced in the control zone CZ2, but the base station BS3 bears most of the burden, and this time, the base station BS3 needs to be controlled.

【0008】

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

【0009】

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

【0010】

[Problems to be Solved by the Invention]

In the conventional mobile communication system and its traffic control method described above, when mobile stations are partially distributed, the degree of concentration can be relaxed for a control zone in which a mobile station concentration zone exists. However, there is a drawback that traffic congestion occurs in one of the control zones and communication is not possible in any control zone.

【0011】

An object of the present invention is to provide a mobile communication system capable of reducing a non-communication state even when mobile stations are unevenly distributed in a part thereof, and a traffic control method thereof.

【0012】

[Means for solving problems]

The mobile communication system of the present invention collects communication traffic information for each part zone from a plurality of base stations that control a control zone that can support a mobile station by dividing it into a plurality of part zones, and from the plurality of base stations. The higher-level control station has, based on the communication traffic information, with respect to each of the plurality of base stations so that the call loss rate between the plurality of base stations and the mobile station is minimized. It is configured to provide means for supplying control information for adjusting the communication support range for each part zone.

【0013】

Further, each of the plurality of base stations in the present invention measures the output electric field strength of the mobile station in units of the part zones to specify which base station and what part zone the mobile station is located in. Formed with means.

【0014】

Further, each of the plurality of base stations in the present invention has one or a plurality of antennas capable of changing the output electric field strength as a means for supplying control information for adjusting the communication support range for each part zone. Formed with a device.

【0015】

Further, each of the plurality of base stations in the present invention is formed by providing means for collecting communication traffic information between the base station and the mobile station in the part zone unit and transmitting the information to the higher control station. To.

【0016】

Further, the higher-level control station in the present invention is formed by providing means for controlling the communication support range of each of the plurality of base stations as a group.

【0017】

Further, the higher-level control station in the present invention 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. It is formed with means for issuing an instruction to each of the base stations to adjust the radio support range of each base station.

【0018】

Further, the higher-level control station in the present invention obtains 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 location registration as the communication traffic information from the plurality of base stations. It is formed by providing a means for calculating the output electric field strength required for each part zone so as to reduce the call loss rate in each base station unit by collecting and weighting each state.

【0019】

Further, the traffic control method of the mobile communication system of the present invention includes a plurality of base stations that divide and control a control zone capable of supporting a mobile station into a plurality of part zones, and the part zone units from the plurality of base stations. The upper control station has a higher control station that collects communication traffic information of the above, and the higher control station stores the control zone number, the part zone number, and the mobile station status data given to each mobile station registered in the location. When the call loss rate of each base station is reduced by providing a storage means and a second storage means for storing the traffic volume information that can be controlled by each base station, the part zone information of each base station, and the position information of the base station. In calculating the output electric field strength required for each part zone unit, the first and second storage means are used to perform traffic information collection processing and traffic control processing.

【0020】

Further, the higher-level control station in the present invention is formed so as to execute the traffic information collection process and the traffic control process at an arbitrary timing.

【0021】

Further, the traffic information collection process in the present invention includes a search step for sequentially searching the communication traffic information of each base station, and an extraction step for extracting communication traffic information for each part zone based on the search result of the search step. After that, for each part zone, the number of mobile stations whose location is registered but is currently turned off, the number of mobile stations that are turned on and in standby mode, and the number of mobile stations currently in use. It is formed to include a counting step to count and.

【0022】

Further, in the traffic control process of the present invention, a limit search step for searching the potential traffic density of each base station and finding a potential traffic density limit that can tolerate the call loss rate, and a base station that needs to be shared in the limit search step are found. At that time, the calculation step of calculating how much traffic sharing is possible between each part zone and the base station adjacent to that part zone and the leveling of the traffic of the entire base station are performed, and the above-mentioned It is formed including a traffic leveling processing step of outputting an output control signal from a higher-level control station to each base station.

【0023】

Further, in the traffic leveling process of the present invention, a search step of initializing a search counter of a base station requiring control and then searching for a base station requiring control and a base requiring control in the search step are performed. When there is no station, processing is terminated depending on whether or not there is a change in traffic sharing, or the process returns to the search step. On the other hand, when there is a base station that needs control in the search step, the search counters of peripheral base stations are initialized and shared. Includes a determination step of searching for possible peripheral base stations and determining the number of base stations that can be shared, and a data update step of obtaining the share up to the shareable limit based on the result of the determination step and updating the potential traffic density data. , The search counter of the base station that needs to be controlled is updated after the data update step, and the search step is repeated.

【0024】

BEST MODE FOR CARRYING OUT THE INVENTION

In the traffic control of a mobile communication system, the present invention further subdivides and recognizes a range (control zone) controlled by each base station into a plurality of ranges (part zones), and each part zone is recognized as a part zone. The number of mobile stations existing inside and one of the states of "in use", "standby for reception", and "power off after location registration" for each mobile station (hereinafter, these information are collectively communicated). It has a base station that has a function to collect traffic information) and a function that receives communication traffic information from a plurality of base station groups and controls to level the traffic volume of each base station based on the information. By having a higher-level control station, even if mobile stations in the control zone are unevenly distributed without adding base stations, the traffic in the control zone exceeds the control capacity of the base station. This is to reduce the rate at which the mobile station becomes unable to communicate (call loss rate).

【0025】

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

【0026】

1 (a) and 1 (b) are a configuration diagram showing an outline of a communication system for explaining one embodiment of the present invention and a configuration diagram of a control zone thereof. As shown in FIGS. 1 (a) and 1 (b), the present embodiment controls radio base stations BS1 to BSi that manage and control a plurality of mobile stations 1, respectively, and these radio base stations BS1 to BSi. It has a higher-level control station 2, and the higher-level control station 2 has a memory 3 for storing information given to each mobile device whose location is registered, and a storage means for storing information of each radio base station. ..

【0027】

First, the radio base station BSi (i: any number) has a directional antenna device that can change the output electric field strength in any direction at multiple levels, and the control zone CZi is divided into multiple part zones PZi1 to PZij. I manage it. Further, the mobile station 1 represented here exists in the control zone CZi and is under the control of the base station BSi. This base station BSi collects the communication traffic information of the mobile station 1 for each part zone PZi1 to PZij, and the collected information is handed over to the upper control station 2 and stored in the memory 3.

【0028】

On the other hand, the upper control station 2 has controllable traffic amount information Fi of each base station BS1 to BSi under its own control, part zone information of each base station, and base station position information, and communication traffic information in the memory 3. Based on the potential traffic density calculated from (control zone number, part zone number, mobile station status data), base stations that may exceed the controllable traffic volume of the base station and adjacent base stations with low potential traffic density The output of the directional antenna is adjusted to change the control zone to reduce the call loss rate. At this time, the mobile stations are unevenly distributed in the control zone by calculating the change ratio based on the potential traffic density for each part zone and comprehensively judging the information of a plurality of base stations in the upper control station 2. However, we are trying to reduce the call loss rate more accurately.

【0029】

In short, in a mobile communication system consisting of a plurality of mobile bodies, a base station, and a higher-level control station that controls a plurality of mobile bodies, each base station provides a directional antenna capable of varying the output electric field strength in an arbitrary direction at multiple levels. It has a plurality of control zones, and has a 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 the communication traffic information to the upper control station 2. The upper control station 2 stores communication traffic information from a plurality of base stations in the memory 3, and the potential traffic density for each base station and each part zone calculated from the controllable traffic volume of each base station and the communication traffic information. Based on the above, each base station has a function of designating the output electric field strength of each directional antenna so that the call loss rate can be reduced.

【0030】

At that time, the upper control station collects each information in a support area (group) consisting of a plurality of base stations, that is, in a group unit to investigate the traffic, and the base station outputs a part zone unit according to the command of the upper control station. Can be adjusted.

【0031】

FIG. 2 is a processing flow diagram for collecting communication traffic information in FIG. As shown in Fig. 2, when the data for obtaining the potential traffic density is periodically updated, the communication traffic information collection process composed of hardware or software or a mixed system thereof is managed by the host control station 2. It is executed at regular intervals.

【0032】

First, the communication traffic information of each base station in the memory 3 managed by the upper control station 2 is sequentially searched by the processing steps S100 to S103 and S115. Then, after the communication traffic information for each part zone is extracted by the processing steps S104 to S109 and S114, the location is registered for each part zone by S111 and S116 to S120, but the power is currently turned off. The number of mobile stations Rij, the number of mobile stations Pij that is turned on and in standby mode, and the number of mobile stations currently in use Bij are counted. Further, the search counter initialization step S110 is a pointer for recollecting base station information. That is, this search counter is for identifying each base station under the control of the upper control station 2, and each counter corresponds to each base station. In short, the counter as a pointer is incremented between SORI steps S110 to S120, and the information of the corresponding base station is collected. Further, from the count result, the latent traffic density Dij in the part zone is calculated in the processing step S112, and the latent traffic density Di of the entire base station is calculated in the processing step S113. At this time, the latent traffic density Dij of a certain part zone PZj of any base station BSi is expressed by the following equation (1). Note that a, b, and c are proportional constants.

【0033】

Dij = aRij + bPij + cBij ...... (1) The potential traffic density Di of the entire base station is expressed by the following equation (2). In addition, ijMAX is the maximum number of part zones possessed by the base station BSi.

【0034】

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

【0035】

First, in searching the communication traffic information of each base station, when the host control station 2 is periodically activated, the base station number i under control is initialized by the base station initialization step S100, and then the search is performed. It is determined whether or not all the searches have been completed in the end determination step S101. Here, when all the searches are completed, the process ends, but when all the searches are not completed, the latent traffic Di of the base station i is initialized in the latent traffic initialization step S102. Further, after the latent traffic initialization step S102, it is determined in the base station controlled determination step S103 whether or not the base station i exists under control, and if it does not exist, the controlled base is determined in the processing step S115. The station number i is updated, and the process returns to step S101. As a result, the communication traffic information of each base station is searched, that is, the validity of the base station i is checked.

【0036】

Next, in extracting the communication traffic information for each part zone, since the base station i exists under the control in the above-mentioned processing step S103, the part zone number of the base station i is obtained by the part zone number initialization step S104. Initialize i. Further, the all-part zone search determination step S105 determines whether or not the search for all part zones of the base station i has been completed, and when all the searches are completed, it is managed in the process step S115 as in the process step S103. The base station number i is updated, and the process returns to process 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 that only registers the position of the base station i with respect to the part zone j is initialized, and then in the initialization step S107, the base station is initialized. Initialize the number of mobile stations Pij that is powered on for part zone j of i, and in initialization step S108, initialize the number of mobile stations Bij that are in use for part zone j of base station i. After initializing the number of mobile stations in sequence, in order to check the effectiveness of the part zone j, it is determined in the determination step S109 whether or not the part zone j exists in the base station i.

【0037】

Here, when the part zone j does not exist in the base station i, the potential traffic density Dij for the part zone j of the base station i is calculated in the calculation step S112, and the potential traffic density Dij is added to the potential traffic Di of the base station i in the addition step S113. , The part zone number j of the base station i is updated in the update step S114, and the process returns to the all part zone search determination step S105 to perform the iterative process.

【0038】

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

【0039】

Next, in counting the number of mobile stations in various states, the mobile station search counter is initialized in the initialization step S110, and then the mobile station information is searched in the location registration information search step S111. At this time, if the information is completed, the above-mentioned calculation, addition, and update steps S112 to S114 are performed. However, if there is information in the information retrieval step S111, the mobile station registration status is changed in the status determination step S116. to decide. When the registration status of the mobile station is determined in this status 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. When the power is on, the number of power-on mobile stations Pij for the part zone j of the base station i is added in the addition step of S118, and when the mobile station is in use, the addition step of the base station i of the base station i is added. Add the number of mobile stations in use Bij for part zone j. 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 location registration information search step S111 to perform iterative processing.

【0040】

The above is a specific processing flow operation in searching for traffic information in FIG. 2, extracting communication traffic information for each part zone, and counting the number of mobile stations in each state.

【0041】

FIG. 3 is a traffic control processing flow diagram in FIG. As shown in FIG. 3, this processing flow is performed by hardware and software in order to reduce the call loss rate by changing the output electric field strength of each base station BSi from the latent traffic density obtained in the processing flow of FIG. 2 described above. Alternatively, it is a traffic control processing flow composed of the mixed system. This process is managed by the host control station 2 and is executed at the same time as the communication traffic information collection process flow shown in FIG. 2 or at another fixed cycle.

【0042】

That is, in the processing steps S200 to S202 and S207, the potential traffic density Di of all the base stations managed by the upper base station 2 is searched, and it is confirmed whether or not the call loss rate exceeds the potential traffic density limit DiTH that can be regarded as acceptable. In any base station BSi, the potential traffic density limit DiTH that can be regarded as an acceptable call loss rate is expressed by the following equation (3), where the amount of traffic that can be controlled by the base station BSi is Fi. Note that e is a constant of proportionality.

【0043】

DiTH = eFi ...... (3) If the potential traffic density Di exceeds the potential traffic density limit DiTH in any base station BSi, it can be said that the base station BSi needs to share traffic by other base stations. If a base station BSi that needs to share this traffic is found, how much traffic is shared between each part zone PZij and the base station BSn adjacent to that part zone in processing steps S203 to S206. Calculate if is possible. Moreover, the shareable traffic volume TRij is calculated by the following equation (4) or (5), where Zn is the area ratio of the part zone PZij that can be shared by the base station BSn. DnDnTH = (Maximum potential traffic density that can be shared by base station BSn) ...... (Four) Zn × Dij = (When the base station BSn shares the maximum part zone PZij Potential traffic density) ...... (Five) It can be said that it is the smaller value of. After collecting this information for all the base stations under control, the potential traffic volume of all the base stations is appropriately shared by pattern recognition or data calculation based on the information collected in the processing step S208. The output electric field strength is obtained, and the output control signal is transmitted to the base station that needs to be controlled in the processing step S209.

【0044】

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

【0045】

First, in calculating the potential traffic density limit, when the potential traffic density limit is calculated periodically, all base station numbers i managed by the upper control station 2 are initialized in the initialization step S200, and then all in the search end determination step S201. It is determined whether or not the search for the management base station is completed. Here, when all the searches have not been completed, in the traffic leveling standard determination step S202, it is determined 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 the number does not exceed the limit, the managed base station number i is updated in update step S207, and the process returns to step S201.

【0046】

On the other hand, in the calculation of traffic sharing, when the reference is exceeded in step S202 described above, the part zone j of the base station i is initialized in the initialization step S203. Then, in the search end determination step S204, it is determined whether or not the search of all the part zones of the base station i is completed, and when all the searches are completed, that is, when the maximum value is exceeded, the same applies in the update step S207 described above. When the update process is performed but all the searches are not completed, that is, the maximum value is not exceeded, the shareable traffic density TRij for the part zone j of the base station i is calculated and recorded in the calculation and recording step S205. When this shareable traffic density TRij is calculated, the part zone j of the base station i is updated in the update step S206, and the search end determination step S204 is repeated.

【0047】

Next, in the traffic leveling, when all the searches are completed in the above-mentioned search end determination step S201, that is, when the maximum value is exceeded, the traffic leveling of the entire managed base station is performed in the traffic leveling step S208. In transmission step S209, the upper control station 2 transmits an output control signal to each base station. This completes the traffic leveling process.

【0048】

FIG. 4 is a pattern diagram showing the first specific example of the traffic leveling process in FIG. As shown in FIG. 4, here, the patterns of four adjacent base stations are shown, and an example of the judgment method in the processing step S208 (traffic leveling of the entire base station) of FIG. 3 described above by pattern recognition is shown. Is. The solid arrows () of each pattern 1,2, ......, pattern 112, ......, pattern 562, ...... in this example represent the primary division and are prioritized. It is a division that should be done as much as possible. In addition, the dotted arrow (-) indicates the secondary division, which should be performed when the primary correction cannot complete the division.

【0049】

When the upper control station 2 targets four adjacent base stations, the potential traffic density can be controlled by the patterns in which the base stations under control are adjacent to each other, that is, "1-3" and "1" in pattern 1. Only 10 part zones of -4, "2-4", "2-5", "2-6", "3-1", "3-2", "3-3", "4-1" and "4-6" Is. Assuming that each of these 10 part zones has two states that require or do not require control, assuming a combination of possible part zone states, it can be seen that there are 2 to the 10th power = 1024 ways. .. Appropriate control can be obtained by preparing control pattern data in advance for all these combinations, such as patterns 1 to 562.

【0050】

5 (a) to 5 (c) are a pre-control configuration diagram showing an outline of a communication system for explaining a first specific example of traffic control according to the present invention, a partially enlarged configuration diagram of the control zone, and control. It is a later block diagram. 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 in FIG. 1 controls a group of base stations as shown in FIG. 5 (a). In addition, it is assumed that the potential traffic density of base station BS2 is at a level that requires control, but mobile station 1 is not normally evenly distributed 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 used are unevenly distributed in a certain part, the mobile station concentration zone 4 is defined as shown in the enlarged view of FIG. 5 (b).

【0051】

First, since the control zone CZ2 is divided into a plurality of part zones PZ21 to PZ26 for recognition, when the communication traffic information collection processing flow of FIG. 2 is executed by periodic activation in the state of FIG. 5 (a), the part Data is extracted that the potential traffic density of zone PZ25 is very high, part zones PZ24 and PZ26 are medium, and the potential traffic density of other part zones PZ21 to PZ23 of base station BS2 and base stations BS1, BS3, BS4 is very small. ..

【0052】

In this embodiment, the potential traffic density limit of each base station BS1 to BS4 is set to 100, and the potential traffic density of part zone PZ25 is 150, and the potential traffic density of part zone PZ24 and PZ26 is 150 for the implementation result of the communication traffic information collection processing flow in FIG. The latent traffic density is defined as 100, the latent traffic density of other part zones PZ21 to PZ23 is defined as 0, and the latent traffic density of base stations BS1, BS3, and BS4 is defined as 10. When the traffic control processing flow shown in FIG. 3 is executed with the above information, the potential traffic density of the base station BS2 is 350 (100 + 100 + 150) in the processing step S202 of FIG. 3, and the potential traffic density limit is reached. Is 100, so it is judged that control is necessary. In the subsequent processing steps S204, S205, and S206, the potential shareable traffic densities of the part zones PZ24, PZ25, and PZ26 are calculated to be 90 shareable each based on the above equations (4) and (5). Since there is no other base station that needs to be controlled, the output radio field intensity of each base station whose potential traffic density is leveled is determined based on the example of pattern 112 in FIG. 4 described above in the processing step S208 based on the above information. Then, in the processing step S209, a control signal is transmitted to each base station. As a result, the control zone of each base station changes as shown in pattern 112 of FIG. 4, and the mobile station concentration zone 4 is shared by each base station as shown in FIG. 5 (c).

【0053】

6 (a) and 6 (b) are a system configuration diagram before control and a system configuration diagram after control for explaining a second specific example of traffic control according to the present invention, respectively. As shown in FIG. 6 (a), here again, the case of controlling the base stations having the same arrangement as in FIG. 5 described above, but the base stations that need to be controlled are two stations, BS2 and BS4, and the mobile station centralized zone. This is the case when 4 is also widespread.

【0054】

In this embodiment as well, since the latent traffic density information is obtained for each part zone in each control zone CZ2 and CZ4, the higher control station 2 can effectively share the latent traffic density by sharing which part zone. You can judge if there is. 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 upper limit of sharing of the base station BS3 is D3TH. It is also possible to make a judgment on the condition that it does not exceed the above. If it is concluded that if both parties are shared, the upper limit of the share can be exceeded, the above-mentioned example of pattern 562 in FIG. 4 will be dealt with, taking that condition into consideration. That is, it is determined that the base station BS2 is mainly shared by the base station BS1 and the base station BS4 is mainly shared by the base station BS3, and the output is such that the control range is changed as shown in Fig. 6 (b). Send a control signal.

【0055】

In the above-described embodiment, the latent traffic density leveling process of the entire base station in the process step S208 of FIG. 3 is solved by preparing the pattern data as shown in FIG. 4 in advance (pattern). The solution by recognition) can obtain the same effect in the data calculation based on the collected information. Hereinafter, this method will be described as another embodiment.

【0056】

FIG. 7 is a traffic leveling processing flow diagram 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 composed of hardware, software, or a mixed system thereof. ..

【0057】

In this case, first, the processing steps S300 and S301 and the processing steps S307 search for information about the base station having a high potential traffic density and needing control. Then, in the processing steps S302 to S304 and S308, the base stations that can share the potential traffic density are extracted from the searched base stations that exist in the vicinity of the base stations that need to be controlled, and the base stations that share the potential traffic density are selected. To do. Further, in the processing steps S305 to S306 and the 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 controlling the potential traffic density in the process step S310, it is possible to level the potential traffic density.

【0058】

In this traffic leveling process, the search counter (not shown) of the base station that needs to be controlled is initialized (S300), and the search is performed to determine the presence or absence of the base station that needs to be controlled (S301). Here, when there is no base station requiring control, it is determined whether or not there is a change in traffic sharing (S310), and when there is no change, the processing is terminated, but when there is a change, the initialization of the search counter is repeated. Esu.

【0059】

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

【0060】

Further, in step S304 of determining the number of base stations, when the number of base stations that can be shared is specified as one, sharing up to the limit that can be shared (S305) is performed. Similarly, when only one base station is extracted in the processing step S308, only the corresponding base station is shared up to the shareable limit (S309). In these processing steps S305 and S309, when the division to the limit is determined, the potential traffic density data is updated (S306).

【0061】

After that, the search counter of the base station that needs control is updated (S307), and when the update is completed, the determination of the presence or absence of the base station that needs control is repeated (S301), and the traffic leveling process is periodically performed. To do.

【0062】

Although the two embodiments have been described above, various modifications are possible in addition to these, and they will be described below.

【0063】

The first is a method of changing "a, b, c" included in the equation (1) described in one embodiment from a constant to a variable. That is, when examining the movement and uneven distribution pattern of mobile station 1 and its usage status, it is conceivable that the state will change significantly depending on the time, day of the week, date, and the like. Therefore, by weighting and changing "a, b, c" in the above equation (1) according to the time, day of the week, date, etc. (treated as a variable), a more appropriate response can be made.

【0064】

For example, on weekday mornings, it is assumed that a large number of mobile stations will move from a residential area to a business district in a short time, and it is unlikely that mobile stations that still exist in the residential area will be used on the spot. To. In such a case, the above-mentioned "a, b, c" is set as a "variable" in order to lower the potential traffic density of the base station controlling the residential area and increase the potential traffic density of the base station controlling the business district. By doing so, it is possible to support traffic in the business area as soon as possible, and it is possible to respond to the movement of mobile stations in a short time.

【0065】

The second method is to switch the periodic activation described in the first embodiment to the dynamic activation. In the above-described embodiment, the processing flow of FIGS. 2 and 3 has been described as a cycle start that is executed at regular intervals, but as in the above modification, the situation depends on the time, day of the week, date, and the like. Is likely to change significantly, so if control was always performed at a fixed time, in some cases the state of the mobile station would change steadily, but there would be too much time to execute the process. Therefore, it may not be possible to cope with the change in the state, and in another case, unnecessary processing may be repeated even though the change in the state does not occur. Therefore, by changing the activation cycle of FIGS. 2 and 3 according to the time, day of the week, date, etc., a more appropriate response can be realized.

【0066】

Further, the third is that in the above-described embodiment, the processes of FIGS. 2 and 3 may not be executed at an appropriate timing due to a start-up cycle or the like. That is, even in the above modified example, it is not possible to deal with the sudden occurrence of traffic due to an unexpected event. Therefore, when the location registration data for the currently existing part zone of the mobile station registered in the memory 3 of FIG. 1 changes by an arbitrary fixed number, the processes of FIGS. 2 and 3 are directly executed. Functions may be provided. In that case, no matter what timing the potential traffic density changes, it is possible to take appropriate measures.

【0067】

[Effect of the invention]

As described above, the mobile communication system and its traffic control method of the present invention divide and manage the base station control zone into a plurality of part zones, and perform comprehensive management of the plurality of base stations by the upper control station. By diverting the existing mobile communication system without a heavy burden such as adding base stations, even if mobile stations are unevenly distributed in the base station control zone, appropriate control for reducing the call loss rate is possible. It has the effect of doing.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the outline of the communication system for demonstrating one Embodiment of this invention, and the structure of the control zone.

[Figure 2]

It is a processing flow diagram which collects communication traffic information in FIG.

[Fig. 3]

It is a traffic control processing flow diagram in FIG.

[Fig. 4]

It is a pattern diagram which shows the 1st concrete example of the traffic leveling processing in FIG.

[Fig. 5]

It is a figure which shows the state before the control, the partial expansion thereof, and after the control for demonstrating the first specific example of the traffic control by this invention.

[Fig. 6]

It is a figure which shows the state before and after control for demonstrating the 2nd specific example of the traffic control by this invention.

[Fig. 7]

It is a traffic leveling process flow diagram for demonstrating another embodiment of this invention.

[Fig. 8]

It is a figure which shows the system configuration before and after control in the traffic control for demonstrating a conventional example.

[Fig. 9]

It is a figure which shows the system configuration before and after control in traffic control for demonstrating another conventional example.

[Explanation of symbols]

1 mobile station 2 Upper control station 3 memory 4 Mobile station concentration zone BS1 ~ BSi wireless base station CZ1 ~ CZi control zone PZi1 ~ PZij Part Zone