Radio control station, radio terminal, base station, communication system, and communication method

• US 7,720,466 B2
• Filed: 05/28/2004
• Issued: 05/18/2010
• Est. Priority Date: 05/28/2003
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Otsu, Toru, Takeda, Shinji
• Primary Examiner(s): Kincaid; Lester
• Assistant Examiner(s): SHEDRICK, CHARLES TERRELL
• Application Number:
  US10/855,640
• Publication Number:
  US 20050037770A1
• Time in Patent Office: 2,181 Days
• Field of Search: 455/419, 455/127.1, 455/434, 455/33.1, 455/464, 455/446, 455/455, 455/515, 455/516, 455/452, 455/450, 455/451, 370/468
• US Class Current: 455/419
• CPC Class Codes: H04W 48/10 using broadcasted information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service

Abstract

A communication system includes a transmission unit configured to transmit control information relating to plural radio communication systems to a radio terminal through a dedicated control channel commonly used by the plural radio communication systems and for transmitting the control information relating to the plural radio communication systems.

Claims

1. A radio control station comprising:

a transmission unit configured to transmit control information to a radio terminal via a dedicated control channel, the control information enables the radio terminal to connect to one of plural radio communication systems for conducting communication, the plural radio communication systems respectively operating in separate frequency bands, a frequency band of the dedicated control channel is outside of the frequency bands of the plural radio communication systems, the control information is provided exclusively to the radio terminal from the radio control station via the dedicated control channel, the control information indicates a frequency band of a pilot channel of each of the plural radio communication systems, and the pilot channel is a first channel that the radio terminal receives when the radio terminal connects to one of the plural radio communication systems.

2. A radio control station of claim 1, wherein the transmission unit transmits congestion information of the plural radio communication systems to the radio terminal.

3. A radio control station of claim 2, further comprising:

an acquisition unit configured to acquire the congestion information of the plural radio communication systems,

wherein the transmission unit transmits the congestion information acquired by the acquisition unit as the control information to the terminal.

4. A radio control station of claim 1, wherein the transmission unit transmits only the control information via the dedicated control channel.

7. The radio control station of claim 1 wherein congestion information is provided thereto by a base station.

10. The radio control station of claim 1, wherein the radio terminal is configured to set a reception frequency at a frequency band of a pilot channel of one of the plural radio communication systems based on the control information indicating the frequency band of the pilot channel of each of the plural radio communication systems.

5. A radio terminal configured to selectively communicate via one of plural radio communication systems, comprising:

a reception unit configured to receive control information via a dedicated control channel; and

a communication unit configured to set reception frequency of the radio terminal to a frequency band of a pilot channel, based on the control information received by the reception unit, the control information enables the radio terminal to connect to one of plural radio communication systems for conducting communication, the plural radio communication systems respectively operating in separate frequency bands, a frequency band of the dedicated control channel is outside of the frequency bands of the plural radio communication systems, the control information is provided exclusively to the radio terminal from the radio control station via the dedicated control channel, the control information indicates a frequency band of a pilot channel of each of the plural radio communication systems, and the pilot channel is a first channel that the radio terminal receives when the radio terminal connects to one of the plural radio communication systems.

6. A radio terminal of claim 5, further comprising:

a priority decision unit configured to decide priority for selecting a radio communication system to be used based on congestion information of the plural radio communication systems,

wherein the reception unit receives the congestion information as the control information, and

the selection unit selects the radio communication system to be used, based on the priority decided by the priority decision unit.

11. The terminal of claim 5, wherein the communication unit is configured to set the reception frequency at the frequency band of the pilot channel of one of the plural radio communication systems based on the control information indicating the frequency band of the pilot channel of each of the plural radio communication systems.

8. A communication system, comprising:

plural radio communication systems;

a radio control station including a transmission unit configured to transmit control information via a dedicated control channel; and

a radio terminal configured to receive the control information via the dedicated control channel, and to set reception frequency of the radio terminal to a frequency band of a pilot channel based on the received control information, the control information enables the radio terminal to connect to one of plural radio communication systems for conducting communication, the plural radio communication systems respectively operating in separate frequency bands, a frequency band of the dedicated control channel is outside of the frequency bands of the plural radio communication systems, the control information is provided exclusively to the radio terminal from the radio control station via the dedicated control channel, the control information indicates a frequency band of a pilot channel of each of the plural radio communication systems, and the pilot channel is a first channel that the radio terminal receives when the radio terminal connects to one of the plural radio communication systems.

12. The communication system of claim 8, wherein the radio terminal is configured to set the reception frequency at the frequency band of the pilot channel of one of the plural radio communication systems based on the control information indicating the frequency band of the pilot channel of each of the plural radio communication systems.

9. A communication method, comprising:

transmitting control information from a radio control station to a radio terminal via a dedicated control channel;

receiving, at the radio terminal, the control information via the dedicated control channel; and

setting, at the radio terminal, reception frequency of the radio terminal to a frequency band of a pilot channel based on the received control information, the control information enables the radio terminal to connect to one of plural radio communication systems for conducting communication, the plural radio communication systems respectively operating in separate frequency bands, a frequency band of the dedicated control channel is outside of the frequency bands of the plural radio communication systems, the control information is provided exclusively to the radio terminal from the radio control station via the dedicated control channel, the control information indicates a frequency band of a pilot channel of each of the plural radio communication systems, and the pilot channel is a first channel that the radio terminal receives when the radio terminal connects to one of the plural radio communication systems.

13. The communication method of claim 9, wherein the setting includes setting the reception frequency at the frequency band of the pilot channel of one of the plural radio communication systems based on the control information indicating the frequency band of the pilot channel of each of the plural radio communication systems.