JP5894625B2 - Mobile communication system - Google Patents

Description

  The present invention relates to a mobile communication system for efficiently accommodating and managing small base stations.

  LTE (Long Term Evolution), which is defined as the next generation communication standard in the standardization organization 3GPP (3rd Generation Partnership Project), is expected to dramatically improve the communication speed. A small base station that constitutes one of the nodes of the LTE network is called a HeNB (Home eNode B) and accommodates a mobile device using the same radio access technology as the macro cell base station (eNode B). The mobile device is, for example, a high-function mobile phone such as a smartphone, and is called a UE (User Equipment). The small base station is connected to the core network of the mobile communication system via a broadband line, and relays communication data of mobile devices located in the local station. A small base station uses a broadband line as a backhaul and is effective in eliminating radio-insensitive areas such as underground and indoor.

  As a communication standard for mobile communication such as a mobile phone, LTE is a technology that has been developed to increase the speed of the third generation mobile phone (3G). VoLTE (Voice over LTE) is a method for communicating voice in accordance with the LTE standard. The communication quality of VoLTE is affected by channel quality such as data delay, jitter, and loss.

  In the LTE network, a small base station gateway device (HeNB Gateway) is provided to accommodate many small base stations (see, for example, Patent Document 1).

JP 2011-41237 A

  Conventionally, the line quality is measured for each certain area about once every several months, and when the deterioration of the line is equal to or greater than a predetermined threshold, the VoLTE is manually switched to the VoLTE non-permitted. When VoLTE is not allowed, a 3G line is used. That is, VoLTE tolerance or VoLTE non-permission is set according to the line quality measured regularly or irregularly.

  However, manual switching of VoLTE permissible or VoLTE non-permitted takes time and lacks speed of line switching according to line quality. In particular, when voice is communicated over the LTE line in a state where the line quality has deteriorated, a user of a mobile device such as a mobile phone can actually feel the deterioration of the line quality.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mobile communication system capable of maintaining voice quality by quickly switching lines according to line quality.

In order to achieve the above object, a mobile communication system according to the present invention includes a small base station constituting one of nodes of a VoLTE network,
A management server for accommodating and managing the small base station;
A line quality measurement server that measures the line quality for each location registration area and notifies the management server of the measurement results;
Have
The management server refers to the measurement result of the line quality notified from the line quality measurement server, determines whether the deterioration of the line quality is equal to or greater than a predetermined threshold,
When it is determined that the threshold value is less than the threshold value, the VoLTE-allowable identifier is notified to the small base station located in the location registration area,
When it is determined that the value is equal to or greater than the threshold value, a VoLTE non-permissible identifier is notified to a small base station located in the location registration area.

  It is preferable to register a VoLTE-allowable identifier and a VoLTE non-permitted identifier for the same location registration area.

When the small base station is notified of a VoLTE-allowable identifier, the small base station connects the mobile device and the communication network via a VoLTE line,
When the small base station is notified of a VoLTE non-permissible identifier, the small base station preferably connects the mobile device and the communication network via a 3G line.

  The management server of the mobile communication system according to the present invention refers to the measurement result of the line quality notified from the line quality measurement server, and determines whether or not the deterioration of the line quality is a predetermined threshold value or more. When it is determined that the deterioration of the line quality is less than the threshold value, a VoLTE-allowable identifier is notified to a small base station located in the location registration area. On the other hand, when it is determined that the value is equal to or greater than the threshold, a VoLTE non-permitted identifier is notified to the small base station located in the location registration area.

  According to the mobile communication system of the present invention, the line quality is measured for each location registration area, and VoLTE permission or VoLTE non-permission is automatically set for each position registration area. The quality of voice can be maintained by switching.

It is a schematic diagram which shows the structure of the mobile communication system which concerns on one embodiment of this invention. It is a figure where it uses for description of registration of VoLTE permissible TAC and VoLTE non-permissible TAC.

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. In other words, the present invention can be implemented with various modifications (combining the embodiments, etc.) without departing from the spirit of the present invention. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic and do not necessarily match actual dimensions and ratios. In some cases, the dimensional relationships and ratios may be different between the drawings.
[Configuration of mobile communication system]

  A mobile communication system according to an embodiment of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a schematic diagram showing a configuration of a mobile communication system according to an embodiment of the present invention.

  As shown in FIG. 1, the mobile communication system 100 according to the present embodiment is configured by, for example, a VoLTE (Voice over LTE) network. VoLTE is a method for communicating voice in accordance with the LTE standard. The mobile communication system 100 according to this embodiment includes a small base station 10, a gateway device 50, a core network 60, a provisioning server 70, a management server 20, and a line quality measurement server 30 as main components.

  Each small base station 10 is called a HeNB and constitutes one of the nodes of the VoLTE network. Each small base station 10 provides a communication service (for example, a voice packet communication service, a multimedia service, etc.) to the mobile device 40 using the same radio access technology as that of a macro cell base station (eNB) (not shown). A cell formed by the small base station 10 is sometimes referred to as a small cell, a femto cell, or a pico cell because the cell size is smaller than that of a macro cell. The small base station 10 may also be called a small cell base station, a femtocell base station, or a picocell base station. The mobile device 40 is a high-function mobile phone such as a smartphone, and is called a UE (User Equipment).

  The gateway device 50 accommodates a plurality of small base stations 10. This small base station gateway device 50 is called a HeNB GW (Home eNodeB Gateway) and is connected to each small base station 10 accommodated via a broadband line or the like. The broadband line is an optical fiber line, an asymmetric digital subscriber line, or a high-speed data line such as a coaxial cable. In the following description, the gateway device 50 for a small base station is simply referred to as a “gateway device” unless there is a specific reason.

  The gateway device 50 includes a virtual eNB (VeNB) for the purpose of efficiently performing communication between each small base station 10 and communication between the small base station 10 and a macro cell (not shown). A plurality of 51 are set. The virtual eNB 51 can be regarded as equivalent to a macro cell. Each virtual eNB 51 can accommodate N (N is a natural number: “256” in the present embodiment) of small base stations 10.

  The small base station 10 is connected to the core network (EPC) 60 of the mobile communication carrier via the gateway device 50. The core network 60 includes a mobility management entity MME (Mobility Management Entity), SGW (Serving Gateway), PGW (Packet Data Network Gateway), HSS (Home Subscriber Server), etc. (all are abbreviated). A provisioning server 70 is connected to the core network 60.

  The provisioning server 70 determines an optimal virtual eNB 51 that is the accommodation destination of each small base station 10 in order to efficiently manage the plurality of small base stations 10 in the gateway device 50. Specifically, each small base station 10 is accommodated in the optimal virtual eNB 51 by using geographical information (for example, information representing latitude and longitude) of each small base station 10 accommodated in the database 71. Is possible.

  Interfaces S1 are defined between the gateway device 50 and the core network 60, between the macro cell base station (not shown) and the core network 60, and between the small base station 10 and the gateway device 50, respectively. Yes. In addition, an interface X2 is defined between the macro cell base station and the gateway device 50 and between the small base station 10 and the gateway device 50, respectively.

  The management server 20 is called HeMS (HeNB Management System), and accommodates and manages the small base station 10 for each location registration area. The management server 20 is installed with accommodation / management programs such as a base station management table, an accommodation design program, and an accommodation check program. The management server 20 includes a database 21. In the database 21, an identifier for each location registration area is registered (Provisioning). The location registration area is called TA (Tracking Area). An identifier registered in each TA is called a TAC (Tracking Area Code). In the management server 20, a VoLTE allowable TAC and a VoLTE non-permitted TAC for each TA are registered in advance.

  With reference to FIG. 2, registration of VoLTE allowable TAC and VoLTE non-permitted TAC will be described. FIG. 2 is a diagram for explaining registration of VoLTE allowable TAC and VoLTE non-permitted TAC.

  FIG. 2 illustrates TAC registration for each TA in Tokyo. As shown in FIG. 2, Tokyo is divided into five location registration areas (TA), for example, A, B, C, D, and E. Two TACs, a VoLTE allowable TAC and a VoLTE non-permitted TAC, are registered in the same location registration area (TA). For example, for the A area, VoLTE allowable TAC (TAC # 1) and VoLTE non-permissible TAC (TAC # 11) are registered. For the B area, VoLTE allowable TAC (TAC # 2) and VoLTE non-permissible TAC (TAC # 12) are registered. For the C, D, and D areas, VoLTE allowable TAC and VoLTE non-permitted TAC are registered in the same manner.

  Referring to FIG. 1 again, the line quality measurement server 30 is configured to measure the line quality for each location registration area (TA). An interface M3 is defined between the line quality measurement server 30 and each small base station 10. The line quality measurement server 30 is installed with a program for measuring line quality. The measurement result of the line quality measured by the line quality measurement server 30 is notified to the management server 20. An interface R4 is defined between the management server 20 and the line quality measurement server 30. An interface R5 is defined between the management server 20 and the gateway device 50.

  When the management server 20 receives the notification from the line quality server 30, the management server 20 refers to the measurement result of the line quality for each location registration area (TA), and the deterioration of the line quality in the location registration area (TA) exceeds a predetermined threshold value. It is determined whether or not there is. For the channel quality, any channel quality criterion such as data delay amount, jitter generation amount, or loss occurrence rate can be used. The threshold value for determining the line quality can be variously determined by the communication carrier as a reference value that is preferable from the viewpoint of maintaining the line quality in the selected line quality determination standard.

  If the management server 20 determines that the deterioration of the line quality of the location registration area (TA) is less than a predetermined threshold, the VoLTE-allowable identifier is assigned to the small base station 10 located in the location registration area (TA). (TAC) is notified. On the other hand, if the management server 20 determines that the deterioration of the line quality of the corresponding location registration area (TA) is equal to or greater than a predetermined threshold value, the management server 20 does not apply VoLTE to the small base station 10 located in the location registration area (TA). An allowed identifier (TAC) is notified.

When the small base station 10 is notified of a VoLTE-allowable identifier (TAC), the small base station 10 applies the VoLTE line to connect the mobile device 40 and the communication network. On the other hand, when the small base station 10 is notified of the VoLTE non-permissible identifier (TAC), the small base station 10 applies the 3G line to connect the mobile device 40 and the communication network.
[Operation of mobile communication system]

  Next, the operation of the mobile communication system 100 according to the present embodiment will be described with reference to FIG. 1 and FIG.

  As shown in FIG. 1, in the mobile communication system 100 according to the present embodiment, the line quality measurement server 30 measures the line quality for each location registration area regularly or irregularly. The channel quality of the small base station 10 is affected by data delay, jitter, loss, and the like. The line quality measurement result is notified from the line quality measurement server 30 to the management server 20.

  In the database 21 of the management server 20, a location registration area (TA) and two types of identifiers (TAC) corresponding to the location registration area (TA) are registered in advance. In the mobile communication system 100 according to the present embodiment, as shown in FIG. 2, two TACs, a VoLTE allowable TAC and a VoLTE non-permitted TAC, are registered in the same location registration area (TA). For example, for the A area, VoLTE allowable TAC (TAC # 1) and VoLTE non-permissible TAC (TAC # 11) are registered.

  Referring again to FIG. 1, when the management server 20 receives the notification from the line quality measurement server 30, the management server 20 refers to the measurement result of the line quality for each location registration area (TA) and stores the location registration area (TA). It is determined whether or not the deterioration of the line quality is not less than a predetermined threshold value. The threshold is set based on, for example, an actual value of channel quality of the VoLTE channel.

  If the management server 20 determines that the deterioration of the line quality of the location registration area (TA) is less than a predetermined threshold, the VoLTE-allowable identifier is assigned to the small base station 10 located in the location registration area (TA). (TAC) is notified. For example, when it is determined in FIG. 2 that the deterioration of the channel quality of the small base station 10 in the A area is less than a predetermined threshold, the VoLTE-allowed TAC # is applied to the small base station 10 located in the A area. 1 is notified (see FIG. 2). The management server 20 instructs the gateway device 50 to create a new VeNB as necessary.

  When the small base station 10 is notified of a VoLTE-allowable identifier (TAC), the small base station 10 connects the mobile device 40 and the communication network via a VoLTE line. For example, when VoLTE-allowed TAC # 1 is notified to the small base station 10 in the area A, the small base station 10 connects the mobile device 40 and the communication network via the VoLTE line (see FIG. 2). If a VoLTE line has already been set up in the small base station 10 in the A area, the connection with the VoLTE line is continued. When a 3G standard line is set in the small area base station 10 in the A area, the 3G line is switched to the VoLTE line.

  On the other hand, if the management server 20 determines that the deterioration of the channel quality of the small base station 10 is equal to or greater than a predetermined threshold, the management server 20 identifies a VoLTE non-permissible identifier for the small base station 10 located in the location registration area (TA). (TAC) is notified. For example, when it is determined that the deterioration of the line quality of the small base station 10 in the A area is equal to or greater than a predetermined threshold, the TAC # 11 that is not allowed to VoLTE is notified to the small base station 10 located in the A area. (See FIG. 2).

  When the small base station 10 is notified of the VoLTE non-permissible identifier (TAC), the small base station 10 connects the mobile device 40 and the communication network according to the 3G standard. For example, when VoLTE non-permitted TAC # 11 is notified to the small base station 10 in the area A, the small base station 10 connects the mobile device 40 and the communication network through a 3G line. If the VoLTE line is already set in the small base station 10 in the A area, the VoLTE line is switched to the 3G line. Further, when a 3G line is set in the small area base station 10 in the A area, the connection with the 3G line is continued.

Therefore, according to the mobile communication system 100 according to the present embodiment, the line quality is measured for each location registration area (TA), and the permission or non-permission of VoLTE is automatically set for each location registration area (TA). Can do.
(Other embodiments)

  Although the present invention has been described by the embodiments as described above, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques should be apparent to those skilled in the art.

  For example, the gateway device 50 may be configured to have the function of the management server 20. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

  In the above embodiment, the quality measurement server measures the line quality for each location registration area, and the management server sets whether or not VoLTE is allowed or not allowed for the small base station based on the measurement result of the line quality. However, it is not limited to this. For example, for a location registration area where the line quality is predicted to deteriorate in a specific time zone based on past quality measurement data, it is managed without waiting for the measurement of the line quality when the specific time zone is reached. The server may perform feedforward control that sets the small base station in the location registration area to VoLTE non-permitted. For example, it is possible to apply the feedforward control during a period (for example, before and after the year-end and New Year countdown) in which the line quality is known to deteriorate due to an increase in traffic.

  Furthermore, in the above-described embodiment, the setting of VoLTE permissible or VoLTE non-permitted for the small base station based on the measurement result of the channel quality is performed in real time. However, the present invention is not limited to this. It is possible to secure real-time performance (responsiveness) by repeating the measurement of the line quality and the control to the small base station according to the measurement result in a short period of time. On the other hand, if the line quality fluctuates before and after the threshold value and is determined to be equal to or higher than the threshold value and set to VoLTE non-permissible, and the case where the line quality is determined to be lower than the threshold value and set to VoLTE allowable, frequent switching occurs. The change in voice quality may be irritating to the user. In order to prevent this, when the setting is changed to one of VoLTE permissible or VoLTE non-permitted, it is preferable to prohibit the immediate return of the setting to the other. For example, when the management server changes the setting, the setting cannot be returned for a certain period. In addition, when the line quality measurement result continuously shows deterioration of the line quality for a certain period, it is set to VoLTE non-permissible for the first time, or when the line quality is continuously improved, VoLTE is allowed for the first time. You may control to set.

DESCRIPTION OF SYMBOLS 100 ... Mobile communication system, 10 ... Small base station, 20 ... Management server, 30 ... Line measurement server, 40 ... Mobile station.

Claims (3)

A small base station constituting one of the nodes of the VoLTE network;
A management server for accommodating and managing the small base station;
A line quality measurement server that measures the line quality for each location registration area and notifies the management server of the measurement results;
Have
The management server refers to the measurement result of the line quality notified from the line quality measurement server, determines whether or not the deterioration of the line quality is equal to or greater than a predetermined threshold,
When it is determined that the threshold value is less than the threshold value, the VoLTE-allowable identifier is notified to the small base station located in the location registration area,
A mobile communication system, characterized by notifying a non-permissible identifier for VoLTE to a small base station located in the location registration area when it is determined that the threshold is greater than or equal to a threshold value.   The mobile communication system according to claim 1, wherein a VoLTE allowable identifier and a VoLTE non-permissible identifier are registered in the same location registration area. When the small base station is notified of a VoLTE allowable identifier, the small base station connects the mobile device and the communication network via a VoLTE line,
The mobile communication according to claim 1 or 2, wherein when the small base station is notified of a VoLTE non-permissible identifier, the small base station connects a mobile station and a communication network via a 3G line. system.

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