Mobile communication system and wireless base station device

• US 7,546,111 B2
• Filed: 02/17/2006
• Issued: 06/09/2009
• Est. Priority Date: 02/18/2005
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Nakano, Yoshihisa
• Primary Examiner(s): Appiah; Charles N
• Assistant Examiner(s): DOAN, KIET M
• Application Number:
  US11/356,226
• Publication Number:
  US 20060189317A1
• Time in Patent Office: 1,208 Days
• Field of Search: 455/404.1, 455/522, 455/435, 455/452.1, 455/456.5, 455/440, 370/335
• US Class Current: 455/404.1
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A mobile communication system with which the time required for handover is short and which has a superior network operating efficiency. In the mobile communication system of the present invention, each wireless base station measures the strength of the radio waves received from a wireless terminal irrespective of whether or not the destination of the radio waves is the wireless base station itself. The respective wireless base stations mutually provide the radio wave strength measurement result. The wireless base stations replies to the request for handover from wireless terminal only when the radio wave of itself is strongest. In addition, when the processing load is large, the wireless base station selects another wireless base station for which the radio wave strength from the wireless terminal is large and switches the connection.

Claims

1. A mobile communication system, comprising:

a wireless base station that measures the strength of radio waves received from a wireless terminal irrespective of whether or not the destination of the radio waves is the wireless base station itself;

a communication network that communicably connects between said wireless base station and other wireless base stations; and

a controller that creates a terminal management table that contains identification information on said wireless base station itself that measures the radio wave strength, identification information on said wireless base station corresponding to the destination of the radio waves, identification information on said wireless terminal that transmits the radio waves, and the radio wave strength measurement result, and that combines the terminal management table thus created and terminal management tables received from said other wireless base stations by using said communication network, wherein the controller has a relative position identification function that identifies the relative positional relationship of a plurality of wireless base stations by using the combined terminal management table, wherein the controller searches data in which identification information on the wireless base station that measured the radio wave strength is self-identification information, from the combined terminal management table;

reads identification information on the wireless terminal from the searched data;

reads data containing the read wireless terminal identification information from the combined terminal management table;

reads identification information on the wireless base station that measured the radio wave strength from the data thus read; and

judges that the wireless base station corresponding with the wireless base station identification information thus read is an adjoining wireless base station.

2. A mobile communication system, comprising:

a wireless base station that measures the strength of radio waves received from a wireless terminal irrespective of whether or not the destination of the radio waves is the wireless base station itself;

a communication network that communicably connects between said wireless base station and other wireless base stations; and

a controller that creates a terminal management table that contains identification information on said wireless base station itself that measures the radio wave strength, identification information on said wireless base station corresponding to the destination of the radio waves, identification information on said wireless terminal that transmits the radio waves, and the radio wave strength measurement result, and that combines the terminal management table thus created and terminal management tables received from said other wireless base stations by using said communication network, wherein the controller has a handover function that determines a priority access point that is newly connected during handover of the wireless terminal by using the combined terminal management table, the controller reads all of the radio wave strength measurement results of the corresponding wireless terminal from the combined terminal management table;

specifies the largest radio wave strength from the measurement results thus read; and

determines the wireless base station that measured the specified radio wave strength as the priority access point.

3. The mobile communication system according to claim 2, wherein

the controller removes data according to which the newest measurement result is smaller than the previous measurement result, from the measurement result thus read;

and

specifies the largest radio wave strength from the measurement results that are not removed.

4. The mobile communication system according to claim 2, wherein a wireless base station that determines that the wireless base station itself is the priority access point transmits, to the other wireless base stations, a signal requesting that a probe response signal not be transmitted upon receipt of a probe request signal from the wireless terminal.

5. The mobile communication system according to claim 4, wherein the request signal is transmitted to all the wireless base stations in the same domain.

6. The mobile communication system according to claim 5, wherein the request signal is transmitted to wireless base stations in adjoining domains.

7. The mobile communication system according to claim 2, wherein the request signal is transmitted to all the wireless base stations that belong to the same mobile communication system.

8. The mobile communication system according to claim 2, wherein the priority access point is determined each time a new combined terminal management table is created.

9. The mobile communication system according to claim 2, wherein the priority access point is determined in a predetermined cycle.

10. A mobile communication system, comprising:

a wireless base station that measures the strength of radio waves received from a wireless terminal irrespective of whether or not the destination of the radio waves is the wireless base station itself;

a communication network that communicably connects between said wireless base station and other wireless base stations; and

a controller that creates a terminal management table that contains identification information on said wireless base station itself that measures the radio wave strength, identification information on said wireless base station corresponding to the destination of the radio waves, identification information on said wireless terminal that transmits the radio waves, and the radio wave strength measurement result, and that combines the terminal management table thus created and terminal management tables received from said other wireless base stations by using said communication network, wherein the controller has a load distribution function that switches the communication connection between the corresponding wireless base station and the wireless terminal to a communication connection between another wireless base station and the wireless terminal, wherein the controller selectes the wireless terminal for which the measurement result is smallest;

searches another wireless base station that can be communicably connected to the selected wireless terminal; and

selects the searched wireless base station as the wireless base station that is communicably connected to the wireless terminal.

11. The mobile communication system according to claim 10, wherein the controller executes the load distribution function when the processing load of the corresponding wireless base station is larger than a predetermined value.

12. The mobile communication system according to claim 10, wherein, when a plurality of wireless base stations are selected, the controller communicably connects the wireless terminal and the wireless base station for which the measurement result is largest.

13. The mobile communication system according to claim 10, wherein the controller removes the wireless base station for which the newest judgment result is smaller than the previous measurement result, from the searched wireless base stations;

and

selects the wireless base station for which the newest measurement result is largest from the wireless base stations that are not removed as the wireless base station that is communicably connected to the wireless terminal.

14. The mobile communication system according to claim 10, wherein the controller transmits, to the selected wireless base station, a signal requesting that a probe response signal be transmitted upon receipt of a probe request signal from the wireless terminal.

15. The mobile communication system according to claim 10, wherein the controller transmits, to the wireless base stations that are not selected, a signal requesting that a probe response signal not be transmitted upon receipt of a probe request signal from the wireless terminal.