Abstract:
A system and a method for connecting macro cellular base stations into mini type base stations are applicable to a mobile communication apparatus having a covering range provided by macro cell base stations upon entering into a range provided by mini type base stations for automatic switching. The method includes establishing a database stored with information related to a geographic distribution for mini type base stations and a listing of authorized admission for allowing mobile communication apparatus to enter; acquiring the geographic area of the mobile communication equipment in order to search the database for at least one mini type base station based on International Mobile Subscriber Identity of the mobile communication apparatus for allowing the mobile communication apparatus to enter into the searched mini type base station from the macro cell base stations for communication.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a handover technique provided in switching to different communication systems, and more particularly, to a system and method for processing connection from a macro cellular base station to a mini type base station such as, a Femtocell base station. 
         [0003]    2. Description of the Prior Art 
         [0004]    Functionality of individual base stations in a wireless communication network system usually depends on the flow and features of the locations where the base stations are situated at. For example, macro cell base stations covered a large coverage are utilized in an area with sparsely distributed population and for high-speed users so as to increase the area of coverage. Conversely, a region with high density of skyscrapers and a plenty mobile communication users per building is confronted with a problem, that is the indoor areas of those buildings are poorly covered by the macro cell system network. Also, given a large number of mobile communication users, the capacity of the macro cell system tends to be inadequate. 
         [0005]    Femtocell base stations are regarded as a way to expand the coverage of a mobile communication network and the enhancement of system&#39;s capacity, in which the Femtocell base stations can effectively overcome the aforesaid problems resulting from the macro cell base stations. However, in practice, the integration of a macro cell system and a femtocell system is seldom easily achieved. As a matter of fact, the base stations or access point devices of the femtocell system are required in a large number, further, the femtocell starts and shuts down independently and randomly. Therefore, it is impossible to acquire, in advance, any messages and operating parameters of the base station or access point devices that are closer to a nearby femtocell system which is covered within the coverage of the macro cell system; as a result, the position information of the base station or the access point device operating under the femtocell system cannot be notified to the mobile communication apparatus. In other words, after the mobile communication apparatus moves out from the coverage of the macro cell system into the coverage of the femtocell system, the mobile communication apparatus cannot stop receiving a signal from the macro cell system and start receiving a signal from the femtocell system, that is, when the macro cell system and the femtocell system integrated together, it cannot effectively switch between the macro cell system and the femtocell system. 
         [0006]    Accordingly, it is imperative to devise a technique of switching between a macro cell system and a femtocell system. 
       SUMMARY OF THE INVENTION 
       [0007]    In light of the aforesaid drawbacks of the prior art, it is an objective of the present invention to provide a system and method for processing connection from a macro cell base station to a mini type base station, so that a mobile communication apparatus moving out from the coverage of the macro cell base station and falling within the coverage of the mini type base station can stop receiving a signal from the macro cell base station and start receiving a signal from the mini type base station. 
         [0008]    To achieve the above and other related objectives, the present invention provides a system and method for processing connection from a macro cell base station to a mini type base station. The system of the present invention processes the connection from the macro cell base station to the mini type base station so that the automatic execution of handover is achieved as soon as the mobile communication apparatus moves out of the coverage of the macro cell base station into the coverage of the mini type base station. The system of the present invention comprises: a database for storing information related to a geographic distribution for all the mini type base stations and a list of the mini type base stations for permitting authorized admission of the mobile communication apparatus; a receiving module for receiving detected information related to a geographic area of the mobile communication apparatus and International Mobile Subscriber Identity (IMSI) of the mobile communication apparatus; and a searching module for searching the database for at least one of the mini type base stations distributed across the geographic area of the mobile communication apparatus according to the geographic area information and the IMSI of the mobile communication apparatus received by the receiving module so that the communication signals of the mobile communication apparatus are switched from the macro cell base station to one of the searched mini type base stations. 
         [0009]    In another embodiment of the present invention, the system further comprises a selecting module for selecting the mini type base stations which are distributed across the geographic area of the mobile communication apparatus and permit an authorized admission of the mobile communication apparatus according to all the mini type base stations distributed across the geographic area of the mobile communication apparatus searched by the searching module from the database and the authorized admission list stored in the database, and creating a conversion table in accordance with the selected mini type base stations and the macro cell base station currently offering the communication service to the mobile communication apparatus in order to allow the communication signals of the mobile communication apparatus to be switched from a macro cell base station to one of the mini type base stations in the conversion table, so as for the mobile communication apparatus to communicate with the admitting mini type base station after the conversion. 
         [0010]    In the system, the selecting module enables the mobile communication apparatus to conduct a survey on communication condition according to the mini type base stations in the conversion table and switch communication signals of the mobile communication apparatus from the macro cell base station to one of the mini type base stations according to a survey result fed back by the mobile communication apparatus, provided that the communication condition survey is satisfactorily conducted on the one of the mini type base stations, so as for the mobile communication apparatus to communicate with the mini type base station that passes the communication condition survey. 
         [0011]    The method for processing connection from a macro cell base station to a mini type base station according to the present invention is configured for use in a communication network system comprising a plurality of macro cell base stations, a plurality of mini type base stations, and a mobile communication apparatus. The method comprises the steps of: (1) creating a database in the communication network system for storing information related to a geographic distribution for the mini type base stations and a list of the mini type base stations permitting authorized admission of the mobile communication apparatus; (2) detecting information related to a geographic area of the mobile communication apparatus and acquiring IMSI of the mobile communication apparatus; (3) searching the database for at least one of the mini type base stations distributed across the geographic area of the mobile communication apparatus; and (4) switching the mobile communication apparatus to at least one of the mini type base stations that is distributed across the geographic area of the mobile communication apparatus permitting authorized admission of the mobile communication apparatus according to the searched at least one mini type base station and the authorized admission list stored in the database. 
         [0012]    In another embodiment of the present invention, the system switches the mobile communication apparatus to one of the mini type base stations that is distributed across the geographic area of the mobile communication apparatus to permitting authorized admission of the mobile communication apparatus according to one of the searched mini type base stations and the authorized admission list stored in the database to create a conversion table in accordance with the selected mini type base stations and the macro cell base station currently offering the communication service to the mobile communication apparatus, and conducting a survey on communication condition according to the mini type base stations in the conversion table so as to switch the communication signal of the mobile communication apparatus from the macro cell base stations to the mini type base stations that are passed the communication condition survey according to a survey result and for the mobile communication apparatus in order to communicate with those mini type base stations passed the communication condition survey. 
         [0013]    In conclusion, with a system and method for switching from a macro cell base station to a mini type base station according to the present invention, it is feasible to switch a mobile communication apparatus from the coverage of a macro cell base station to the coverage of a mini type base station automatically. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1A  is a block diagram of a system for processing connection from a macro cell base station to a mini type base station in accordance with an embodiment of the present invention; 
           [0015]      FIG. 1B  is a block diagram of a system for processing connection from a macro cell base station to a mini type base station in accordance with another embodiment of the present invention; 
           [0016]      FIG. 2A  is a flow chart of a method for processing connection from a macro cell base station to a mini type base station in accordance with an embodiment of the present invention; and 
           [0017]      FIG. 2B  is a flow chart of a method for processing connection from a macro cell base station to a mini type base station in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0018]    The present invention is herein illustrated with specific embodiments, so that one skilled in the pertinent art can easily understand other advantages and effects of the present invention from the disclosure of the invention. 
         [0019]    Also, the present invention is illustrated with simple schematic drawings to let persons skilled in the art gain insight into the basic principles of the present invention. In practice, the form, quantity, and proportion of elements of a system of the present invention are subject to changes as needed. 
         [0020]    Referring to  FIG. 1A , a block diagram of a system  10  for processing connection from a macro cell base station to a mini type base station according to an embodiment of the present invention is shown. As shown in the drawing, the system  10  for processing connection from a macro cell base station to a mini type base station according to the embodiment of the present invention enables an automatic execution of handover once the mobile communication apparatus  4  moves out from the coverage of a macro cell base station  2  and falls within the coverage of a mini type base station  3 , such as a Femtocell base station, so that the original service received by the mobile communication apparatus  4  is maintained rather than interrupted. The macro cell base station  2 , the mini type base station  3  and the mobile communication apparatus  4  in this embodiment are recited in the singular term for the purpose of a clear demonstration how the claimed method switches and operates between different types of base stations. 
         [0021]    In this embodiment, the system  10  for switching from a macro cell base station to a mini type base station according to the present invention is capable of applying to 3G mobile communication network system, whereas a list of local base stations that permit authorized admission of the mobile communication apparatus  4  is stored in the mini type base station  3  and the macro cell base station  2 . Hence, in this embodiment, the mobile communication apparatus  4  has the qualification for a registered user of a mini type system and a macro cell system. The mobile communication apparatus  4  is exemplified by a mobile terminal of WCDMA and TD-SCDMA, applicable to 3GPP Release 99, Release 4, Release 5, Release 6, Release 7 and Release 8 as well as subsequent the 3G standards, and capable of positioning. 
         [0022]    In this embodiment, the system  10  for processing connection from a macro cell base station to a mini type base station comprises a database  101 , a receiving module  102  and a searching module  103 . In terms of the 3G mobile communication system, the database  101 , the receiving module  102  and the searching module  103  are installed in a data center of the 3G mobile communication system. The database  101  stores information related to the geographic distribution for all the macro cell base stations  2 , mini type system parameter information and a list of the macro cell base stations  2  that permit the authorized admission of the mobile communication apparatus  4 . The list stored in the database  101  corresponds to the list stored in the mini type base station  3 . 
         [0023]    In this embodiment, the mini type system parameter information comprises the power of signals emitted from the mini type base station  3 , the radius coverage of the mini type base station  3 , the cell ID of the mini type base station  3  and the IP address of the mini type base station  3 . 
         [0024]    The receiving module  102  receives information related to the geographic area of the mobile communication apparatus  4  detected by the macro cell base station  2  and the International Mobile Subscriber Identity (IMSI) of the mobile communication apparatus  4 . In this embodiment, the macro cell base station  2  detects the geographic area of the mobile communication apparatus  4  on a regular basis. In practice, the macro cell base station  2  detects the geographic area of the mobile communication apparatus  4  every 10 seconds, the time interval of detection is not limited to 10 seconds, it can be changed or set accordingly to the needs of the systems. 
         [0025]    The searching module  103 , after receiving the geographic area information and the IMSI of the mobile communication apparatus  4  from the receiving module  102 , searches the database  101  for at least one of the mini type base stations  3  distributed across the geographic area of the mobile communication apparatus  4 , so as for the communication signals of the mobile communication apparatus  4  are switched from the macro cell base station  2  to one of the searched mini type base station  3 . 
         [0026]    The system for processing connection from a macro cell base station to a mini type base station to achieve the handover of the mobile communication apparatus from a macro cell system to a mini type system. 
         [0027]      FIG. 1B  shows a block diagram of a system  10 ′ for processing connection from a macro cell base station to a mini type base station in accordance with another embodiment of the present invention. The present embodiment, which is different from the embodiment illustrated in  FIG. 1A  in the system  10 ′ comprises a selecting module  104  and a conversion table  105 . The searching module  103  of this embodiment, after receiving the geographic area information of the mobile communication apparatus  4  from the receiving module  102  and the IMSI of the mobile communication module  104 , searches all mini type base stations  3  distributed across the geographic area according to the geographic area of the mobile communication apparatus  4 . For example, if the geographic area of the mobile communication apparatus  4  received by the receiving module  102  is zone A, the searching module  103  will search the database  101  for all mini type base stations  3  distributed in zone A, and list all the searched mini type base stations  3 . 
         [0028]    The selecting module  104  selects the mini type base stations  3 , which permit authorized admission of the mobile communication apparatus  4  and are distributed across the geographic area of the mobile communication apparatus  4  according to all the mini type base stations  3  found by the searching module  103  and the authorized admission list stored in the database  101 . 
         [0029]    The selecting module  104  creates a conversion table in accordance with the mini type base stations  3  selected and the macro cell base station  2  currently offering communication service to the mobile communication apparatus  4 . A target is selected from the conversion table for the conversion. Communication signals of the mobile communication apparatus  4  are switched from the macro cell base station  2  to one of the mini type base stations  3  in the conversion table. Consequently, after the conversion, the mobile communication apparatus  4  communicates with the admitting mini type base station  3 . 
         [0030]    Also, the selecting module  104  enables the mobile communication apparatus  4  to conduct a survey on communication condition according to the mini type base stations  3  in the conversion table  105  and switch communication signals of the mobile communication apparatus  4  from the macro cell base station  2  to one of the mini type base stations  3  according to the survey result fed back by the mobile communication apparatus  4 , wherein one of the mini type base stations  3  having the best communication condition is revealed in the survey result. The mobile communication apparatus  4  communicates with the mini type base station  3 , which has the best communication condition. 
         [0031]    In other words, the selecting module  104  selects the mini type base stations  3 , which fall within the coverage of the macro cell base station  2  located within the geographic area of the mobile communication apparatus  4  and permit an authorized admission of the mobile communication apparatus  4 , and the selected mini type base stations  3  are regarded as the switch targets. After moving out the coverage of the macro cell base station  2 , the mobile communication apparatus  4  switches to the mini type base stations  3  so as to receive the communication service therefrom. Hence, there is no interruption of communication service of the mobile communication apparatus  4  occurred. 
         [0032]    In this embodiment, the selecting module  104  further comprises a determining unit  1040  for determining whether to switch the communication signals of the mobile communication apparatus  4  from the macro cell base station  2  to one of the mini type base stations  3  in the conversion table according to the survey result fed back by the mobile communication apparatus  4 . An affirmative determination is followed by the switch, but a negative determination is followed by the receiving module  102  continually receiving the IMSI of the mobile communication apparatus  4  and the geographic area of the mobile communication apparatus  4  detected by the macro cell base station  2 . 
         [0033]    In this embodiment, switching the communication signals of the mobile communication apparatus  4  from the macro cell base station  2  to one of the mini type base stations  3  in the conversion table is effectuated, using software switching or hardware switching process. 
         [0034]    In another embodiment of the present invention, the searching module  103  will search again for the presence of an adjacent mini type base station  3  that falls within the coverage of the macro cell base station  2  only when the receiving module  102  or the searching module  103  receives a change in the geographic area of the mobile communication apparatus  4 . 
         [0035]    When the system of the present invention is applied to the 3-G mobile communication system mentioned-above, the selecting module  104  and the conversion table  105  shown in  FIG. 1B  will be installed in the data center of the 3-G mobile communication system. 
         [0036]    Referring to  FIG. 2A , a flow chart of a method for processing connection from a macro cell base station to a mini type base station according to an embodiment of the present invention. The method is configured for a use in a communication network system comprising a plurality of macro cell base stations, a plurality of mini type base stations, and at least one mobile communication apparatus. In this embodiment, the communication network system is the 3G mobile communication network system. 
         [0037]    In this embodiment, the mobile communication apparatus is exemplified by a mobile terminal of WCDMA and TD-SCDMA, applicable to 3GPP Release 99, Release 4, Release 5, Release 6, Release 7 and Release 8 as well as subsequent 3G standards, and capable of positioning. 
         [0038]    The method comprises the steps of:
       step S 1 , wherein a database is created in the communication network system, and the database stores information related to a geographic distribution for a plurality of mini type base stations, a mini type system parameter information, and a list of the mini type base stations that permit authorized admission of a mobile communication apparatus. The authorized admission list stored in the database corresponds to the list stored in the mini type base station for authorized admission of the mobile communication apparatus. In this embodiment, the mini type system parameter information comprises the power of signals emitted from the Femtocell base station, the radius of coverage of the mini type base station, the cell ID of the mini type base station, and the IP address of the mini type base station. Go to step S 2 ;   step S 2 , wherein the geographic area of the mobile communication apparatus is detected and the IMSI of the mobile communication apparatus is acquired. Go to step S 3 ;   step S 3 , wherein the database is searched for one of the mini type base stations distributed across the geographic area of the mobile communication apparatus. Go to step S 4 ; and   step S 4 , wherein the mobile communication apparatus is switched to one of the mini type base stations distributed across the geographic area of the mobile communication apparatus and permits an authorized admission of the mobile communication apparatus according to the mini type base station found and the authorized admission list stored in the database.       
 
         [0043]    Referring to  FIG. 2B , a flow chart of a method for processing connection from a macro cell base station to a mini type base station according to another embodiment of the present invention is shown. The present embodiment is different from the embodiment shown in  FIG. 2A  in which the method of the present embodiment searches all the mini type base stations distributed across the geographic area of the mobile communication apparatus according to the geographic area of the mobile communication apparatus, selects a mini type base station distributed across the geographic area of the mobile communication apparatus and permits the authorized admission to the mobile communication apparatus, to create a conversion table. The method of the present embodiment can be applied to a communication network system comprising a plurality of macro cell base stations, a plurality of mini type base stations, and at least a mobile communication apparatus. 
         [0044]    The method of this present embodiment comprises the following steps:
       step S 10 , wherein a database is created in the communication network system to store information related to a geographic distribution for a plurality of mini type base stations, a mini type system parameter information and a list of the mini type base stations that permit the authorized admission of a mobile communication apparatus. The authorized admission list stored in the database corresponds to the list stored in the mini type base station for authorized admission of the mobile communication apparatus. Go to step S 20 ;   step S 20 , wherein the macro cell base station detects geographic area of the mobile communication apparatus and sends information related to the detected the geographic area and the IMSI of the mobile communication apparatus to the communication network system. In this embodiment, the geographic area of the mobile communication apparatus is detected on a regular basis, for example, every 10 seconds; however, the time interval of detection is not restricted to 10 seconds, and it can be altered according to the requirements of the system. For example, upon detection of a change in the geographic area of the mobile communication apparatus, updated information of the geographic area of the mobile communication apparatus and the IMSI of the mobile communication apparatus are sent to the data center. Go to step S 30 ;   step S 30 , wherein the communication network system searches the database for all the mini type base stations distributed across the geographic area of the mobile communication apparatus according to the IMSI of the mobile communication apparatus. For example, if the geographic area of the mobile communication apparatus is detected as the zone A in step S 20 , the data center will search the database for all the mini type base stations located within zone A and then lists all the mini type base stations found in step S 30 . Go to step S 40 ;   step S 40 , wherein the communication network system selects the mini type base stations, which are distributed across the geographic area of the mobile communication apparatus and permit the authorized admission of the mobile communication apparatus, according to the found mini type base station and an authorized admission list stored in the database. Go to step S 50 ;   step S 50 , wherein the communication network system creates a conversion table from the mini type base stations selected and the macro cell base station currently offering communication service to the mobile communication apparatus so that a switch target is selected from the conversion table. Go to step S 60 ;   step S 60 , wherein the communication network system enables the mobile communication apparatus to conduct a survey on communication condition according to the mini type base stations in the conversion table, and receives a survey result fed back by the mobile communication apparatus. Go to step S 70 ;   step S 70 , wherein the communication network system determines whether to switch the communication signals of the mobile communication apparatus from the macro cell base station to one of the mini type base stations in the conversion table according to the survey result fed back by the mobile communication apparatus. Upon an affirmative determination, go to step S 80 . Upon a negative determination, go back to step S 20 ; and   step S 80 , wherein the communication signals of the mobile communication apparatus switch from the macro cell base station to one of the mini type base stations in the conversion table, so as for the mobile communication apparatus to provide communication via the mini type base station. In this embodiment, switching the communication signal of the mobile communication apparatus from the macro cell base station to one of the mini type base stations in the conversion table is operated under the software switching or hardware switching process.       
 
         [0053]    Note that the aforesaid communication network system is operated under the 3G mobile communication system, and under the 3G mobile communication system, the database that stores the authorized admission list and conversion table are installed in a data center of the 3G mobile communication system. 
         [0054]    In conclusion, a system and method for switching from a macro cell base station to a mini type base station according to the present invention overcomes a drawback of prior art as follows: the number of the base stations of a mini type system is always a large number, and the system starts and shuts down independently and randomly such that a data center is unable to acquire in advance, therefore, any messages and wireless communication network system parameters of the base station of a nearby mini type system that fall within the coverage of the macro cell system that offers communication service to a mobile communication apparatus cannot be obtained; as a result, it is impossible to inform the mobile communication apparatus of a list of mini type base stations adjacent thereto; thus the mobile communication apparatus cannot detect any signal from a mini type base station and thereby cannot switch to the mini type base station. On the other hand, the present invention the communication signals of the mobile communication apparatus can be switched from the macro cell base station to a base station of a mini type system anytime without any restriction. 
         [0055]    The foregoing descriptions of the detailed embodiments are provided to illustrate and disclose the features and functions of the present invention and are not intended to be restrictive of the scope of the present invention. It should be understood by those in the art that many modifications and variations can be made in the aforesaid embodiments according to the spirit and principle of the present invention. Hence, all equivalent modifications and variations made by persons skilled in the art without departing from the spirit and technical philosophy disclosed in the present invention should still fall within the scope of the invention as set forth in the appended claims.