Mobile communication system and base station control apparatus

• US 7,496,383 B2
• Filed: 01/31/2006
• Issued: 02/24/2009
• Est. Priority Date: 02/01/2005
• Status: Active Grant

• Current Assignee: FIPA Frohwitter Intellectual Property AG
• Original Assignee: Hitachi Communication Technologies, Ltd. (Hitachi, Ltd.)
• Inventors: Yamazaki, Kenji, Yano, Masaaki, Kurata, Ryosuke, Kasai, Daiho
• Primary Examiner(s): Le; Nhan T
• Application Number:
  US11/342,884
• Publication Number:
  US 20060189308A1
• Time in Patent Office: 1,120 Days
• Field of Search: 455/422.1, 455/436, 455/442, 455/550.1, 455/561, 370/328, 370/329, 370/331
• US Class Current: 455/561
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 48/10 using broadcasted information
• CPC Class Codes: H04W 88/12 Access point controller devices

Abstract

A neighbor sector is automatically set to effectively perform soft handover. A base station corresponding to a first sector to communicate with a wireless terminal and a base station corresponding to a second sector to start communication with the wireless terminal due to movement of the wireless terminal or the like transmit a terminal identifier acquired from the wireless terminal, a time and a sector identifier to a base station control part (control part in the following). The control part successively stores the received sector identifier into a table correspondingly to the terminal identifier and the time received from the base station. Besides, the control part refers to the table, judges whether different sector identifiers are stored in a previously determined time range, regards a pair of the two different sector identifiers as neighbor sector candidates and counts the number of times they are regarded as the neighbor sector candidates. With respect to the neighbor sector candidates in which the counted number of times is a threshold or more, the control part transmits, to the base station corresponding to one sector of the neighbor sector candidates, a change request including the neighbor sector information concerning the other sector.

Claims

1. A wireless communication system comprising:

one or plural base stations each of which has one or plural sectors and transmits neighbor sector information including, for each sector, a sector identifier of another sector adjacent to the sector and/or information to identify a radio wave from the another sector, to a wireless terminal for each sector; and

a base station control part which includes a connection history table storing, for each terminal identifier of the wireless terminal and correspondingly to a time, a sector identifier of a sector with which the wireless terminal communicates, and is for changing the neighbor sector information transmitted from the base station, wherein

the base station transmits the terminal identifier acquired from the wireless terminal and the sector identifier of the sector communicating with the wireless terminal to the base station control part,

the base station control part receives the terminal identifier and the sector identifier, and stores the sector identifier into the connection history table correspondingly to the terminal identifier and a reception time,

the base station control part refers to the connection history table, judges that in a case where plural different sector identifiers are stored correspondingly to each terminal identifier in a previously determined time period from an arbitrary time, a first sector and a second sector among the plural different sector identifiers are neighbor sector candidates, and counts the number of times they are judged to be the neighbor sector candidates correspondingly to a first sector identifier of the first sector and a second sector identifier of the second sector, and

the base station control part transmits, with respect to the first and the second sector identifiers in which the counted number of times is a previously determined threshold or more, a change request, which includes the second sector identifier and/or information to identify a radio wave from the second sector and is for changing the neighbor sector information from the base station, to the base station corresponding to the first identifier.

2. The wireless communication system according to claim 1, wherein

the base station control part further includes a sector database in which one or plural of pilot signal information and frequency channel information are stored correspondingly to the sector identifiers,

the base station control part refers to the sector database based on the second sector identifier with respect to the first and the second sector identifiers in which the counted number of times is the previously determined threshold or more, and acquires one or plural of corresponding pilot signal information and frequency channel information, and

the base station control part transmits a change request, which includes one or plural of the second sector identifier, the acquired pilot signal information and the frequency channel information and is for changing the neighbor sector information from the base station, to the base station corresponding to the first sector identifier.

3. The wireless communication system according to claim 1, wherein

the base station control part further includes a neighbor sector candidate table in which for each sector, a sector identifier of a neighbor sector candidate of the sector and a count number for counting the number of times of judgment of the neighbor sector candidate are stored correspondingly,

the base station control part counts the number of times by increasing a count number corresponding to the second sector identifier with respect to the neighbor sector candidate table corresponding to the first sector, and

the base station control part refers to the neighbor sector candidate table of each sector to acquire a sector identifier in which a count number is a previously determined threshold or more, and transmits a change request, which includes one or plural of the acquired sector identifier, pilot signal information and frequency information corresponding to the sector identifier and is for changing the neighbor sector information from the base station, to the base station of the sector corresponding to the neighbor sector candidate table.

4. The wireless communication system according to claim 3, wherein

the base station control part deletes sector identifiers stored in the connection history table in order of the first one corresponding to a time when a previously determined period has passed,

when plural different sector identifiers are deleted in a previously determined time width, the base station control part decrements a count number corresponding to a fourth sector identifier among the plural different sector identifiers in the neighbor sector candidate table according to a third sector identifier among the plural different sector identifiers, and

when the count number in the neighbor sector candidate table becomes lower than a previously determined threshold by the decrement, the base station control part transmits a delete request to delete information concerning the fourth sector identifier from the neighbor sector information to the base station corresponding to the third sector identifier.

5. A wireless communication system comprising:

one or plural base stations each of which has one or plural sectors and transmits neighbor sector information including, for each sector, a sector identifier of another sector adjacent to the sector and/or information to identify a radio wave from the another sector; and

a base station control part to change the neighbor sector information transmitted from the base station, wherein

the base station acquires, from a wireless terminal, one or plurality of captured radio wave information indicating radio waves captured from one or plural sectors by the wireless terminal and transmits the captured radio wave information to the base station control part,

the base station control part receives the captured radio wave information from the base station, judges whether plurality of captured radio wave information are received, judges that a first sector and a second sector are neighbor sector candidates among plural sector identifiers each of which corresponds to the plurality of captured radio wave information, and counts the number of times they are judged to be the neighbor sector candidates correspondingly to a first sector identifier of the first sector and a second sector identifier of the second sector, and

the base station control part transmits, with respect to the first and the second sector identifiers in which the counted number of times is a previously determined threshold or more, a change request, which includes the second sector identifier and/or information to identify a radio wave from the second sector and is for changing the neighbor sector information from the base station, to the base station corresponding to the first identifier.

6. The wireless communication system according to claim 5, wherein

the base station control part includes a peripheral radio wave information table in which captured radio wave information concerning the radio wave captured by the wireless terminal from the sector and a sector identifier corresponding to the captured radio wave information are stored for each call identifier to identify a call of the wireless terminal and correspondingly to a time,

the base station further transmits the call identifier to the base station control part,

the base station control part receives the call identifier and the captured radio wave information, and stores the captured radio wave information into the peripheral radio wave information table correspondingly to the call identifier and a reception time, and

the base station control part refers to the peripheral radio wave information table, and judges that plurality of captured radio wave information are received when the plurality of captured radio wave information are stored at the same reception time with respect to each call identifier.

7. The wireless communication system according to claim 5, wherein

the base station control part further includes a sector database in which one or plural of pilot signal information and frequency channel information are stored correspondingly to a sector identifier,

the base station control part refers to the pilot signal information of the sector database based on each piece of the received captured radio wave information to acquire a corresponding sector identifier, and counts the number of times of judgment of neighbor sector candidates correspondingly to the first and the second sector identifiers among the acquired sector identifiers,

the base station control part refers to the sector database based on the second sector identifier with respect to the first and the second neighbor sector identifiers in which the counted number of times is a previously determined threshold or more, and acquires one or plural of the corresponding pilot signal information and frequency channel information, and

the base station control part transmits a change request, which includes one or plural of the second sector identifier, the pilot signal information and the frequency channel information and is for changing the neighbor sector information from the base station, to the base station corresponding to the first sector identifier.

8. The wireless communication system according to claim 5, wherein

the base station control part further includes a neighbor sector candidate table in which for each sector, a sector identifier of a neighbor sector candidate of the sector and a count number for counting the number of times of judgment of the neighbor sector candidate are stored,

the base station control part counts the number of times by increasing the count number correspondingly to another sector identifier corresponding to the second sector identifier and/or the captured radio wave information with respect to the neighbor sector candidate table corresponding to the first sector, and

the base station control part refers to the neighbor sector candidate table of each sector to acquire a sector identifier in which the count number is a previously determined threshold or more, and transmits a change request, which includes one or plural of the acquired sector identifier, pilot signal information and frequency information corresponding to the sector identifier and is for changing the neighbor sector information from the base station, to the base station of the sector corresponding to the neighbor sector candidate table.

9. The wireless communication system according to claim 8, wherein

the base station control part deletes sector identifiers stored in the peripheral radio wave information table in order of the first one corresponding to a time when a previously determined period has passed,

when plural different sector identifiers are deleted in a previously determined time width, the base station control part decrements the count number corresponding to a fourth sector identifier among the plural different sector identifiers in the neighbor sector candidate table of a third sector identifier among the plural different sector identifiers, and

when the count number in the neighbor sector candidate table becomes lower than a previously determined threshold by the decrement, the base station control part transmits a delete request to delete information concerning the fourth sector identifier from the neighbor sector information to the base station corresponding to the third sector identifier.

10. A wireless base station control apparatus comprising:

an interface to transmit/receive information to/from a base station having one or plural sectors;

a connection history table in which a sector identifier of a sector with which a wireless terminal communicates is stored for each terminal identifier of the wireless terminal and correspondingly to a time; and

a processing part to change neighbor sector information which is transmitted from the base station having one or plural sectors to the wireless terminal and includes, for each sector, a sector identifier of another sector adjacent to the sector and/or information to identify a radio wave from the another sector, wherein

the processing part receives, from the base station, a terminal identifier from the wireless terminal and a sector identifier of a sector communicating with the wireless terminal,

the processing part stores the sector identifier into the connection history table correspondingly to the terminal identifier and a reception time,

the processing part refers to the connection history table, judges that in a case where plural different sector identifiers are stored correspondingly to each terminal identifier in a previously determined time period from an arbitrary time, a first sector and a second sector among the plural different sector identifiers are neighbor sector candidates, and counts the number of times they are judged to be the neighbor sector candidates correspondingly to a first sector identifier of the first sector and a second sector identifier of the second sector, and

the processing part transmits, with respect to the first and the second sector identifiers in which the counted number of times is a previously determined threshold or more, a change request, which includes the second sector identifier and/or information to identify a radio wave from the second sector and is for changing the neighbor sector information from the base station, to the base station corresponding to the first identifier.

11. A wireless base station control apparatus comprising:

an interface to transmit/receive information to/from a base station having one or plural sectors; and

a processing part to change neighbor sector information which is transmitted from the base station to a wireless terminal and includes, for each sector, a sector identifier of another sector adjacent to the sector and/or information to identify a radio wave from the another sector, wherein

the processing part receives, from the base station, one or plurality of captured radio wave information indicating radio waves captured by the wireless terminal from one or plural sectors, judges whether plurality of captured radio wave information are received, judges that a first sector and a second sector among plural sector identifiers corresponding to the plurality of captured radio wave information are neighbor sector candidates, and counts the number of times they are judged to be the neighbor sector candidates correspondingly to a first sector identifier of the first sector and a second sector identifier of the second sector, and

the processing part transmits, with respect to the first and the second sector identifiers in which the counted number of times is a previously determined threshold or more, a change request, which includes the second sector identifier and/or information to identify a radio wave from the second sector and is for changing the neighbor sector information from the base station, to the base station corresponding to the first sector identifier.