JPH07162932A - Calling control system for mobile radio communication system - Google Patents

Abstract

PURPOSE:To provide the calling control system for reducing invalid calling and improving the probability of call incoming at a mobile radio communication system. CONSTITUTION:History information 33 of position registration is recorded for each radio terminal in a memory 30 inside an exchange and when there is call incoming, a calling area to perform calling is decided based on the position registration history information in the past of a terminal. When there is no response to calling from the radio terminal, corresponding to the conditions of a system side load, calling is performed again in all the calling areas. When there is no response to the calling in all the calling areas from the radio terminal, the radio terminal is registered out of the area, and calling to the same terminal is suppressed until fixed time passes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call control system in a mobile radio communication system accommodating a cordless telephone or a cellular telephone.

[0002]

2. Description of the Related Art In a mobile radio communication system in which a plurality of base stations are dispersedly arranged in a service area and a communication service is provided by a radio channel to a mobile body such as a car phone or a mobile phone, a limited frequency In order to effectively use the band, a plurality of frequencies constituting the band are allocated to the base station according to a periodic repeating pattern, and a plurality of base stations separated by a certain distance or more that do not have the risk of mutual interference use the same frequency. The communication service is provided within each call area (cell). In this case, since the number of terminals that one radio base station can accommodate is limited, in order to increase the number of communication channels per unit area in the call area,
There is a tendency to increase the number of base stations in the service area and reduce the size of the communication area under the control of each base station.

However, when the call area is reduced, the frequency of transition of each mobile body from one call area to an adjacent call area increases, and the number of position registration processes executed each time the call area is changed increases. Problems such as shortage of control channels necessary for location registration procedure and reduction of call processing capacity due to increased load for location registration occur.

When the call area per base station is increased, the number of position registrations described above is reduced, but the number of wireless terminals that can be located in the call area is increased. Therefore, there is a disadvantage that some terminals cannot call due to insufficient channels. is there.

As one measure for solving such a problem, a calling area is formed by a group of wireless base stations each having a small calling area, and when a wireless terminal receives an incoming call, all the calling areas in the calling area are set. There is a method of instructing a wireless base station to transmit a calling signal. According to this method,
Since the call area under the control of each base station is small, the number of mobile terminals located in each call area can be reduced, and the channel shortage can be resolved, and if the location registration is performed for each calling area having a relatively large area, Since this is good, there is an advantage that the number of position registrations accompanying the movement of the wireless terminal can be reduced.

[0006]

However, the conventional paging system in which incoming calls are simultaneously made from a plurality of radio base stations in the paging area has a relatively small amount of movement, for example,
When applied to the on-premise mobile wireless system for mobile phones carried by employees, when receiving a call to each wireless terminal,
There is a lot of waste due to calling in a plurality of other cells where the corresponding wireless terminal does not exist.

If the wireless terminal receives a call before registering its location in the call area of the moving destination, the incoming call fails. Such a failure of the incoming call occurs especially in the wireless terminal located near the boundary of the calling area. As a method of preventing the failure of the incoming call to the terminal located near the boundary of the calling area, a method of making a call to a calling area physically adjacent to the calling area currently registered is possible. Then, for example, if the owner of the wireless terminal moves at high speed in the building using an elevator,
There is a problem that the incoming call fails when the user moves to another calling area that is not adjacent to the location-registered area.

An object of the present invention is to provide a call control system capable of efficiently receiving an incoming call for a wireless terminal in a mobile wireless communication system.

Another object of the present invention is to provide a call control system capable of efficiently receiving an incoming call to a radio terminal without deteriorating the call processing capability, especially in a mobile radio communication system on a premises.

[0010]

In order to achieve the above object, in the call control method of the present invention, the location registration history information of each wireless terminal is stored, and the location registration history information of the terminal is stored at arrival. The mobile terminal is called in one or a plurality of specific calling areas determined based on the above.

Further, another feature of the present invention is that a first calling mode for calling a terminal device having an incoming call in a specific calling area and a second calling mode for calling in all calling areas. The size of the calling area to be called is dynamically selected according to the load condition of the communication system.

The first calling mode includes calling in one area specified based on the latest location registration information and calling in a plurality of calling areas specified from location registration history information. For example, when the load of the system is high, the calling mode is selected by calling in one specific area in which the latest location registration is performed.
If there is room in the system, calls are made in a plurality of calling areas specified by the location registration history information. If there is no response to this, the call is made in the second mode to all the call areas.

If the size of the calling area is a modification of the dynamic selection, and if there is a margin in the system, the calling in the second mode may be performed to all the calling areas from the beginning.
Also, when calling fails in one calling area,
The call may be made in a plurality of call areas specified from the position registration history information, and the call may be further made in the second call mode depending on the result.

Further, another feature of the present invention is that if there is no response from the terminal to the call in the second mode, it is considered that the terminal has moved out of the service area, and information indicating that fact. When a call is registered to the wireless terminal in which the information indicating the out-of-service movement is registered, the call is suppressed for a certain period of time after the registration of the information. The out-of-service registration may be performed when the call in the first call mode fails.

[0015]

[Function] There is a characteristic pattern in the daily activities of mobile wireless terminal users in the office, and other specific departments or areas that are determined by the user's duties are centered around the desk or workplace where each user is enrolled. I often come and go.

The present invention pays attention to such characteristics in the behavior pattern of each user, and stores the past location registration history information in addition to the latest location registration information for each mobile terminal, thereby receiving an incoming call. In addition to calling in the latest location registration area, it is possible to make a call to a plurality of specific calling areas having a high existence probability determined from location registration history information for the requested wireless terminal. By making a call in one or a plurality of specific calling areas, it is possible to reduce the number of base stations that have executed unnecessary calls and effectively use system resources.

Further, according to the present invention, since the size of the calling area can be dynamically changed according to the processing capacity of the system side depending on the margin situation, when the load is high,
With a minimum calling area, or when the load is light, calling can be efficiently performed by calling in a specific plurality of calling areas or all calling areas. Furthermore, when an incoming call is received by a wireless terminal that has been registered as out-of-range, by suppressing the call for a certain period of time after being registered as out-of-range, it is possible to prevent a decline in call processing capability.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a wireless exchange showing an embodiment of the present invention. The wireless exchange 1 includes a call controller 2, a time division switch 3, a system clock 4, a load measuring module 5, a main memory 10, and a wireless base station controller (6-1).
~ 6-N) and trunks (8-1 to 8-K). The radio base station control devices (6-1 to 6-N)
Each is connected to a subscriber line (7-1 to 7-N), and the trunks (8-1 to 8-K) are respectively connected to the office lines (9-1 to 9-
-K). In the main memory 10, a location management table 3 for storing the area where the wireless terminal exists, etc.
0 and a calling area table 40 indicating the correspondence between the calling area and the wireless base station are stored.

FIG. 2 is a diagram showing a connection relationship between the radio base station, the exchange, and the public network. The exchange 1 is connected to the central office line (9-1 to 9
-K) is connected to the public network 13 and the subscriber line (7-
1-7-N), the wireless base station (20-1-20-
N). Radio base stations (20-1 to 20-N)
Respectively have wireless call areas (11-1 to 11-N) and talk with the wireless terminals 12 located in each wireless call area. Further, at least one or more wireless call areas form a calling area (22-1 to 22-n), and the location of the wireless terminal 12 is recorded for each calling area (position registration). When an incoming call is received from the extension line or the like connected to the office line (9-1 to 9-K) or the subscriber line (7-1 to 7-N) to the wireless terminal 12, the call is registered with the location of the wireless terminal. For all wireless base stations in the area,
Sending of a ringing signal is commanded.

FIG. 3 is a block diagram of the position management table 30 for storing the position of the wireless terminal 12 and referring to it for determining the calling area to be instructed to send the calling signal when the wireless terminal 12 receives a call. Here is an example: Position management table 30
Is a wireless terminal number 31 for identifying the wireless terminal 12,
It is composed of a field for storing out-of-service information 32 for indicating whether or not the wireless terminal 12 is present in the calling area, and location registration information 33.

In the present invention, a plurality of storage fields of the location registration information 33 are stored in order to store the location registration history of each wireless terminal. For example, in the case of a private cordless telephone system, all call areas in the system are stored. Prepare for the number of pieces.

The out-of-range information 32 includes an out-of-range display flag 32a indicating whether or not the wireless terminal exists in the calling area,
The location registration information 33 includes, for example, an out-of-service registration date and time 32b indicating the date and time when the location does not exist in the calling area. The location registration information 33 includes, for example, a calling area number 33a, a registration time 33b, and a location registration flag 33c.

The out-of-service display flag 32a indicates the wireless terminal 12
Is not in the calling area, for example, "1"
Is recorded, and when communication is possible, “0” is recorded.
Further, the out-of-service registration date and time 32b records the date and time when the wireless terminal 12 was last not present in the calling area. In the registration time 33b, the latest time when the position of the wireless terminal 12 is registered in the calling area designated by the calling area number 33a is recorded. The position registration flag 33c is
Indicates whether or not the location is registered in the calling area designated by the calling area number 33a. For example, "1" is recorded when the location is registered, and "0" is recorded when the location is not registered. It In the case of having a table of all calling areas, a method of omitting the calling area numbers 33a and storing them in the memory in the ascending order of calling area numbers may be considered.

FIG. 4 shows another example of the position registration information 33 shown in FIG. In this example, in addition to the calling area number 33a, the registration time 33b, the position registration flag 33c, the existence time 33
d is recorded. As the presence time 33d, the presence time of the wireless terminal 12 in the calling area designated by the calling area number 33a is recorded as the cumulative time. The presence time 33d is referred to together with the position registration flag 33c to determine a calling area in which the wireless terminal is likely to exist when the wireless terminal receives an incoming call. The information recorded in the position registration table is cleared manually or automatically after a certain period of time.

FIG. 5 shows a calling area table 40 used to obtain the wireless base stations forming the calling area whose location is registered when calling the wireless terminal 12. The calling area table 40 has a calling area number 4
1 and the radio base station number 42. When the number of recorded radio base station numbers is less than the number of prepared tables, a code for indicating the end of data, for example, "FFF
"F" is recorded.

Next, the location registration processing procedure will be described. When the use of the wireless terminal 12 is started, the location registration is first performed in the existing calling area 22-1. Wireless terminal 1
2 transmits a position registration signal 50 including a wireless terminal number and a signal type (position registration) as shown in FIG. 6, the wireless base station 20-2 which receives the position registration signal 50 calls the position registration signal 50. The position registration signal 51 to which the number is added is sent to the exchange.

The main control unit 2 of the exchange, which has received the position registration signal 51, searches for an empty area in the position management table,
The wireless terminal number 31, the calling area number 33a, and the registered time 33b are newly recorded.

At the second and subsequent position registrations from the same terminal, the wireless exchange reads the wireless terminal number from the position registration signal 51 received from the wireless base station, and searches the position management table 30 based on this wireless terminal number. , The location management information address of the location registration requesting wireless terminal 12 is obtained.
Next, the calling area number in the received position registration signal 51 is read out, and the same calling area number as the read out calling area number is searched from the calling area number 33a in the position registration information 33. If there is position registration information 33 having the same calling area number as the received calling area number in the position registration signal 51, the current time is read from the system clock 4 and written at the registration time 33b. Received location registration signal 5
If there is no location registration information 33 having the same calling area number as the calling area number in 1, the location where the location registration information 33 is not recorded is searched, and the calling area number 33a,
Write the registration time 33b. Also, every time the location registration is performed, the registration time 33b of all the location registration information 33 of the wireless terminal 12 that has transmitted the location registration signal is compared with the current time read from the system clock 4, and the elapsed time is predetermined. If it is longer than the value, the location registration information 33
The position registration flag 33c of is cleared to "0".

When the location registration information shown in FIG. 4 is used, the following processing is performed in addition to the location registration processing described above. After the use of the wireless terminal 12 is started and the position registration is first performed, the registration time 33b of the position registration information 33 and the current time read from the system clock 4 are periodically compared to perform the position registration. The elapsed time from the start, that is, the time existing in the calling area where the location registration is performed is obtained and recorded in the existing time 33c. When the wireless terminal moves in a different calling area and performs location registration, similarly, the current time is read from the system clock 4 to determine the existence time in the calling area before moving, and the existence in the calling area before moving. Add to time.

FIG. 7 is a flowchart showing an example of a processing procedure executed by the exchange when an incoming call is received by the wireless terminal. First, when there is an incoming call at the wireless terminal (step 10
2) The location management table 30 is searched for the location where the wireless terminal number of the incoming call is stored (104), and the out-of-range display flag 32a in the out-of-range information 32 of the location management table 30 is checked (106). . Out-of-range display flag is "1"
If not, it is judged that the wireless terminal having the incoming call is present in the calling area, and the load is measured by the load measuring module 5 in the exchange (108). The measured load is compared with a predetermined reference value (110), and if the load is less than the reference value, the position registration flag 33c in the position registration information 33 of the position management table 30 is set to "1". However, all the calling area numbers 33a are read (112). The read call area number is retrieved from the call area table 40, the radio base station number which constitutes the call area is obtained (114), and a call signal is transmitted to the radio base station having the radio base station number ( 1
16).

If there is a response from the wireless terminal to the call signal, call processing is performed (120). When there is no response, for example, the call signal is transmitted from the wireless base stations in all the calling areas of the system (122), and if there is a response from the wireless terminal, the call processing is performed (120), and if there is no response. Out-of-service display flag 32a of the position management table 30
Write "1" to the system clock 4
Read out and record it in the out-of-service registration date and time 32b (12
6).

As a result of the load measurement (108), if the load exceeds the predetermined reference value, the registration time 33b in the position registration information 33 of the position management table 30 indicates the latest calling area number 33a. Read (130), and read the calling area number from the calling area table 40.
, The wireless base station number forming the calling area is obtained (132), and a calling signal is transmitted to the wireless base station having this wireless base station number (134). If there is a response from the wireless terminal, call processing is performed (120), and if there is no response, "1" is written in the out-of-service display flag 32a of the location management table 30. The date and time of writing is read from the system clock 4 and recorded in the out-of-service registration date and time 32b (138). Check the out-of-range display flag 32a (1
06), when "1" is set in the out-of-service area display flag 32a, for example, the wireless terminal is temporarily moved to a place where the radio wave does not reach, is registered as out-of-service area, and returns to the calling area again. The following process is performed in case the registration fails and the location is not registered.

First, the load is measured by the load measuring module 5 in the exchange (140). The measured load is compared with a predetermined reference value (142), and if the load is less than or equal to the reference value, the out-of-service registration date and time 32b is read (144), and then the current date and time is read from the system clock 4. , Elapsed time after registration outside the service area is calculated (146). The elapsed time is compared with a predetermined reference value (148), and if the elapsed time is less than or equal to the reference value, the process is terminated without calling. If the elapsed time exceeds the reference value, the call signal is transmitted from the radio base stations in all the call areas (150).

If there is a response from the wireless terminal to the calling signal, the location is registered (156) and then the call processing is performed (158). If there is no response from the wireless terminal to the calling signal, the out-of-service registration information 3 in the location management table 30.
The current date and time read from the system clock 4 is written in the out-of-service registration date and time 32b of 2. As a result of the load measurement (140), if the load is not equal to or less than the reference value, the process ends.

FIG. 8 is a flowchart showing an example of a call control procedure performed based on the information in the position management table 30, and FIG. 9 is a diagram for explaining the concept of the processing.
FIG. 9 shows the presence time 33d of the position registration information 33 in the position management table 30 arranged in descending order, and (a)
Is, for example, the existence time distribution of wireless terminals that are often at the same place or in the vicinity without moving much, (b)
Shows the distribution of the existence time of wireless terminals that move a lot and constantly travel between different areas.

Therefore, for a wireless terminal having an existing time distribution as shown in (a), it is possible to obtain a high incoming call probability by simply making a call in a small number of specific calling areas having a long existing time. It is possible to reduce unnecessary calls.
On the other hand, with respect to the wireless terminal having the existing time distribution as shown in (b), it is necessary to make a call in many calling areas in order to receive a call with a certain probability or more.

For such a request, for example, n0
Ratio of the sum Ts of the existence times up to the th and the total sum TN of the existence times: The minimum n0 such that Ts / TN exceeds a predetermined threshold value C is obtained, and n0 pieces of the existence times from the first to the n0th The call signal may be transmitted to the call area.

In the processing procedure of FIG. 8, when an incoming call is received by the wireless terminal 12, first, the wireless terminal number 31 of the location management table 30 is searched to find the location where the location management information of the wireless terminal is stored. The position registration flag 33c of the position registration information 33 is set, that is, the calling area number 33a which is position registered is obtained (202). Next, the calling area number is searched from the calling area table 40 to obtain the wireless base station numbers forming the calling area, and the calling signals are transmitted to these wireless base stations (203). If there is a response from the wireless terminal to the call, the call process is performed (230) and the process ends.
If there is no response from the wireless terminal, the following processing is performed.

First, the counter n for the number of calling areas is cleared (208) and the sum Ts of the existing times is cleared (210).
Then, the presence time 33d is read from all the position registration information 33 of the wireless terminal concerned from the position management table 30,
The sum TN thereof is calculated (211). Next, the counter n
Is incremented (212), and the n-th calling area number of the existing time is read (214). The retrieved calling area number is retrieved from the calling area table 40,
The radio base station number forming the calling area is read out, and the call signal is transmitted to the radio base station having the read out radio base station number (216).

If there is a response from the wireless terminal to the calling signal, call processing is performed (230) and the processing is terminated.
If there is no response from the wireless terminal, the read existence time T
n is added to the existence time sum Ts (220), and the ratio Ts / TN between the calculated existence time sum Ts and the existence time sum TN is compared with a predetermined value C (222). Ts / TN
However, if it is not larger than C, the processes of 212 to 220 are repeated. If Ts / TN becomes larger than C, all the calling area numbers from the n + 1th to the Nth existing times are read out, and a calling signal is transmitted from the radio base station forming the read calling area (224). If there is a response from the wireless terminal, call processing is performed (230) to end the processing, and if there is no response from the wireless terminal, out-of-service registration is performed (228) and the processing ends.

[0042]

According to the present invention, the history information of location registration is stored for each wireless terminal and the calling area is determined based on this location registration history information. It is possible to prevent a call from being made to a terminal in an area wider than necessary, and it is possible to suppress a decrease in call processing capability due to a call signal transmission process of the exchange. Also, since the size of the calling area can be dynamically determined according to the system load situation, even if there is no response in a specific calling area, it does not affect the call processing capacity and has a high probability. It is possible to make a successful incoming call.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration of a wireless exchange implementing the present invention.

FIG. 2 is a diagram showing an example of the overall configuration of a mobile radio communication system.

FIG. 3 is a diagram showing an example of a table for recording location management information.

FIG. 4 is a diagram showing an example of location registration information.

FIG. 5 is a diagram showing an example of a calling area table.

FIG. 6 is a diagram showing an example of a position registration signal.

FIG. 7 is a flowchart showing an embodiment of a call processing procedure when an incoming call arrives at a wireless terminal.

FIG. 8 is a flowchart showing another embodiment of a call processing procedure when an incoming call is received by a wireless terminal.

FIG. 9 is a diagram showing a distribution of the existence time of each calling area of the wireless terminal.

[Explanation of symbols]

1 ... Wireless exchange, 2 ... Call processing unit, 3 ... Time division switch,
4 ... System clock, 5 ... Load measurement module, 6-
1 to 6-N ... Radio base station control unit, 7-1 to 7-N ... Subscriber line, 8-1 to 8-K ... Trunk, 9-1 to 9-K ... Station line, 10 ... Main memory, 11-1 to 11-N ... wireless communication area, 12 ... wireless terminal, 20-1 to 20-N ... wireless base station, 22-1 to 22-n ... calling area, 30 ... location management table, 40 ... calling area table.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikiya Naemura 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Ltd. Information & Communication Division

Claims (6)

[Claims] 1. In a mobile radio communication system in which a group of radio base stations constitutes one calling area, location registration history information is stored for each radio terminal, and when a radio terminal receives an incoming call, A call control method in a mobile radio communication system, characterized in that a call is made to the radio terminal in one or a plurality of specific call areas selected based on location registration history information. 2. The paging control method in a mobile radio communication system according to claim 1, wherein the location registration history information includes a paging area and registration time information. 3. A mobile radio communication system in which a plurality of radio base stations constitutes one calling area, and a first calling mode for calling in at least one specific calling area and calling in all calling areas. Mobile radio communication characterized by having a second calling mode to be performed, and dynamically selecting the number of calling areas to be called to a wireless terminal to receive a call according to the load situation on the system side. Call control method in the system. 4. A call in the first call mode is made to a wireless terminal to receive a call in a plurality of specific call areas, and when the call fails, a call in the second call mode is executed. The paging control method in the mobile radio communication system according to claim 3, wherein it is determined whether or not the paging control method is performed. 5. In addition to the latest location registration information, location registration history information is stored for each wireless terminal, and the first or a plurality of specific calling areas selected based on the location registration information are used to store the location registration history information. 4. The move according to claim 3, wherein when the call is made in the first call mode and the call fails, the call in the second call mode is made in all the call areas if the load condition of the system side allows. A call control method in a wireless communication system. 6. When no call is received in spite of calling in the second calling mode for all calling areas, out-of-service registration is performed for out-of-service registration with respect to the wireless terminal that received the call. Within a certain period of time since it was held,
The call control system in a mobile radio communication system according to claim 3, wherein a call to the radio terminal at the time of an incoming call is suppressed.