RADIO COMMUNICATION SYSTEM, RADIO TERMINAL, BASE STATION, AND BASE STATION SEARCH METHOD

• US 20090190553A1
• Filed: 06/04/2007
• Published: 07/30/2009
• Est. Priority Date: 06/06/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsumoto, Takashi, Nakae, Hironori, Hayashino, Hiroshi, Ukita, Yosuke, Masuda, Yoichi
• Granted Patent: US 8,359,061 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 92/20 between access points

Abstract

A wireless communication system includes a wireless terminal and a plurality of base stations that can communicate with each other via a predetermined communication path that is different from the wireless communication path to the wireless terminal. The wireless terminal transmits a request signal to one of the base stations to request a response signal from another base station. The one base station transfers the received request signal to the other base station via the predetermined communication path. Upon reception of the request signal transferred from the one base station, the second base station transmits a response signal to the wireless terminal via the predetermined channel. The wireless terminal receives the response signal transmitted from the second base station via the predetermined channel.

Claims

1. A wireless communication system that includes a wireless terminal and a plurality of base stations, in which the plurality of base stations can communicate with each other via a predetermined communication path that is different from a wireless communication channel to the wireless terminal, wherein

the wireless terminal includes

a request signal transmission unit operable to transmit, to one base station among the plurality of base stations, a request signal for requesting a response signal from one or more other base stations among the plurality of base stations, and

a response signal reception unit operable to receive the response signal transmitted from the one or more other base stations on a predetermined channel,

the one base station includes

a request signal reception unit operable to receive the request signal from the wireless terminal, and

a request signal transfer unit operable to transfer the request signal received by the request signal reception unit to the one or more other base stations via the predetermined communication path, and

the one or more other base stations include

a response signal transmission unit operable to transmit the response signal to the wireless terminal on the predetermined channel upon receiving the request signal transmitted from the one base station.

2. The wireless communication system of claim 1, wherein

the one base station is a base station with which the wireless terminal has established a wireless connection, and the one or more other base stations are base stations with which the wireless terminal has not established a wireless connection.

3. The wireless communication system of claim 1, wherein

in a case that the one or more other base stations are a plurality of other base stations, the predetermined channel is a same channel for each of the plurality of other base stations.

4. The wireless communication system of claim 1, wherein

the wireless terminal further includes

a storage unit operable to store therein channel information indicating a channel used by the one or more other base stations for wireless communication, and

a channel setting unit operable to reference the channel information and set, as the predetermined channel, one channel that is different from the channel used by the one or more other base stations, wherein

the request signal transmission unit transmits information indicating the predetermined channel set by the channel setting unit by including the information in the request signal.

5. The wireless communication system of claim 1, wherein

the one base station further includes

a storage unit operable to store therein channel information indicating a channel used by the one or more other base stations, and

a channel setting unit operable to reference the channel information and set, as the predetermined channel, one channel that is different from the channel used by the one or more other base stations, wherein

the request signal transfer unit transfers information indicating the predetermined channel set by the channel setting unit by including the information in the request signal.

6. The wireless communication system of claim 1, wherein

the one base station is connected, via the predetermined communication path, to the plurality of base stations that include the one or more other base stations,

the wireless terminal further includes

a storage unit operable to store therein identification information for identifying each of the plurality of base stations, and

a selection unit operable to select the one or more other base stations from among the plurality of base stations with reference to the identification information, wherein

the request signal transmission unit transmits identification information pertaining to the one or more other base stations selected by the selection unit by including the information in the request signal, and

the request signal transfer unit transfers the request signal to the one or more other base stations identified by the identification information included in the request signal.

7. The wireless communication system of claim 1, wherein

the one base station is connected, via the predetermined communication path, to a plurality of base stations that include the one or more other base stations,

the one base station further includes

a storage unit operable to store identification information for identifying each of the plurality of base stations, and

a selection unit operable to select the one or more other base stations from among the plurality of base stations with reference to the identification information, wherein

the request signal transfer unit transfers the request signal to the one or more other base stations selected by the selection unit.

8. The wireless communication system of claim 6, wherein

the one base station further includes

a communication state information reception unit operable to periodically receive communication state information indicating respective communication states from each of the plurality of base stations via the predetermined communication path, and

a communication state transmission unit operable to sequentially transmit, to the wireless terminal, the communication state information received by the communication state information reception unit, wherein

the selection unit selects, as the one or more other base stations, a base station whose communication state information indicates a communication state that satisfies a predetermined condition, from among the plurality of base stations.

9. The wireless communication system of claim 7, wherein

the one base station further includes

a communication state information reception unit operable to periodically receive communication state information indicating respective communication states from each of the plurality of base stations via the predetermined communication path, wherein

the selection unit selects, as the one or more other base stations, a base station whose communication state information has indicated a communication state that satisfies a predetermined condition, from among the plurality of base stations.

10. The wireless communication system of claim 1, wherein

the request signal transmission unit transmits the request signal along with a condition pertaining to a communication state of the one or more other base stations,

the request signal transfer unit transfers the request signal, along with the condition, to the one or more other base stations, and

the response signal transmission unit transmits the response signal only if the communication state of the one or more other base stations satisfy the predetermined condition.

11. The wireless communication system of claim 1, wherein

the wireless terminal further includes

a judgment unit operable to judge whether performing handover processing is necessary,

a base station determination unit operable to, in a case that the one or more other base stations are a plurality of other base stations, determine one other base station from among the plurality of other base stations in accordance with the response signals received by the response signal reception unit, and

a handover petition unit operable to petition that handover be performed to the other base station determined by the base station determination unit, wherein

the request signal transmission unit transmits the request signal if the judgment unit has judged that the handover processing is necessary, and

each of the plurality of other base stations further include a handover processing unit operable to perform handover processing for establishing a wireless connection with the wireless terminal upon receiving a handover petition from the wireless terminal.

12. A base station in a wireless communication system that includes a wireless terminal and a plurality of base stations, in which the plurality of base stations can communicate with each other via a predetermined communication path that is different from a wireless communication channel to the wireless terminal, the base station comprising:

a request signal reception unit operable to receive a request signal transmitted from the wireless terminal while the base station and the wireless terminal are connected by a wireless connection;

a request signal transfer unit operable to transfer the request signal received by the request signal reception unit to an other base station from among the one or more other base stations via the predetermined communication path, the other base station not being connected to the wireless terminal by the wireless connection; and

a response signal transmission unit operable to, while the base station is not connected to the wireless terminal by the wireless connection, transmit the response signal to the wireless terminal on the predetermined channel upon receiving a request signal transmitted from a base station, from among the plurality of base stations, that is connected to the wireless terminal by the wireless connection.

13. A wireless terminal in a wireless communication system that includes the wireless terminal and a plurality of base stations, in which the plurality of base stations can communicate with each other via a predetermined communication path that is different from a wireless communication channel to the wireless terminal, the wireless terminal comprising:

a request signal transmission unit operable to transmit, to one base station among the plurality of base stations, a request signal for requesting a response signal from one or more other base stations among the plurality of base stations, the request signal including channel information indicating a predetermined channel; and

a response signal reception unit operable to receive a response signal from the other base station on the predetermined channel.

14. A base station search method in which a wireless terminal searches a plurality of base stations in a wireless communication system that includes the wireless terminal and the plurality of base stations, the plurality of base stations being able to communicate with each other via a predetermined communication path that is different from a wireless communication channel to the wireless terminal, the base station search method comprising:

a request signal transmission step in which the wireless terminal transmits, to one base station among the plurality of base stations, a request signal for requesting a response signal from one or more other base stations among the plurality of base stations;

a request signal reception step in which the one base station receives the request signal from the wireless terminal;

a request signal transfer step in which the one base station transfers the request signal received by the request signal reception unit to the one or more other base stations via the predetermined communication path;

a response signal transmission step in which the one or more other base stations transmit the response signal to the wireless terminal on the predetermined channel upon receiving the request signal transmitted from the one base station; and

a response signal reception step in which the wireless terminal receives the response signal transmitted from the one or more other base stations via the predetermined channel.