Radio communication system, radio communication apparatus and radio communication method, and computer program

• US 20030162535A1
• Filed: 02/25/2003
• Published: 08/28/2003
• Est. Priority Date: 02/28/2002
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sakoda, Kazuyuki, Yamaura, Tomoya, Kunihiro, Takushi, Nishiyama, Fumihiro
• Granted Patent: US 7,085,564 B2
• Time in Patent Office: Days
• US Class Current: 455/422.1
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Under a multi-cell radio communication environment where connection between cells or TDMA frame synchronization is not established, a mobile station carries out an adjacent cell search under low power consumption. Adjacent cell information acquired through search by the mobile station is managed centered on a base station and may be provided by the base station as adjacent cell information, when the mobile station carries out the adjacent cell search. The adjacent cell information includes, for example, a TDMA frame offset between cells so that the mobile station receives a broadcast channel of the adjacent cell at appropriate timing based on the adjacent cell information and therefore does not need to perform unnecessary reception operation in the event of a handoff.

Claims

1. A multi-cell and multi-user radio communication system comprising a plurality of cells having a base station enabled for communication, the cells disposed adjacent to or contiguous to one another, wherein the base station collects and manages adjacent cell information from a mobile station within a cell and provides the adjacent cell information collected within the cell to the mobile station.

2. The multi-cell and multi-user radio communication system as claimed in claim 1, wherein:

communication is carried out in each cell by means of a time division multi access system and each base station transmits intra-cell control information at a time division multiple access frame period within the cell;

the adjacent cell information includes a timing offset value of time division multi access frames of its own cell and an adjacent cell; and

the mobile station carries out reception of intra-cell control information from the adjacent cell at a reception timing which is determined from the timing offset value included in the adjacent cell information acquired from the base station, during an adjacent cell search.

3. A radio communication apparatus operating as a base station under a radio communication environment where intra-cell communications are carried out by means of a time division multiple access system, the radio communication apparatus comprising:

an adjacent cell information reception means for receiving adjacent cell information notified by each mobile station within a cell;

an adjacent cell information management means for managing the received adjacent cell information; and

an adjacent cell information provision means for providing an adjacent cell information stored in the adjacent cell information management means to a mobile station within the cell.

4. The radio communication apparatus as claimed in claim 3, further comprising a cell management means for transmitting a control channel including intra-cell control information for each time division multi access frame period of its own cell, wherein the adjacent cell information include a timing offset value of time division multi access frames of its own cell and the adjacent cell.

5. The radio communication apparatus as claimed in claim 3, wherein the adjacent cell information management means updates the adjacent cell information if receiving adjacent cell information regarding a same adjacent cell from a plurality of mobile stations.

6. The radio communication apparatus as claimed in claim 3, wherein the adjacent cell information management means discards the adjacent cell information upon elapse of a period of time after latest reception.

7. The radio communication apparatus as claimed in claim 3, wherein the adjacent cell information provision means broadcasts the adjacent cell information within the cell.

8. The radio communication apparatus as claimed in claim 3, wherein the adjacent cell information provision means transmits the adjacent cell information to a mobile station within the cell in response to an advance search notice from the mobile station or a request in another format.

9. A radio communication method for operation as a base station under a radio communication environment where intra-cell communications are carried out by means of a time division multiple access system, the radio communication method comprising:

an adjacent cell information reception step for receiving adjacent cell information notified by each mobile station within a cell;

an adjacent cell information management step for managing the received adjacent cell information; and

an adjacent cell information provision step for providing an adjacent cell information stored in the adjacent cell information management step to a mobile station within the cell.

10. The radio communication method as claimed in claim 9, further comprising a cell management step for transmitting a control channel including intra-cell control information for each time division multi access frame period of its own cell, wherein the adjacent cell information include a timing offset value of time division multi access frames of its own cell and the adjacent cell.

11. A radio communication apparatus operating as a mobile station under a radio communication environment where intra-cell communications is carried out by means of a time division multiple access system, the apparatus comprising:

an adjacent cell search means for searching an adjacent cell;

an adjacent cell information notification means for notifying a base station of the adjacent cell information acquired as a result of the adjacent cell search; and

an adjacent cell information acquisition means for acquiring the adjacent cell information from the base station.

12. The radio communication apparatus as claimed in claim 11, wherein

a base station within each cell transmits a control channel including intra-cell control information at a time division multiple access frame period within the cell;

the adjacent cell search means tries reception of a control channel transmitted by an adjacent cell; and

the adjacent cell information notification means notifies the base station of adjacent cell information acquired through the adjacent cell search and including a timing offset value of time division multi access frames of its own cell and the adjacent cell.

13. The radio communication apparatus as claimed in claim 11, wherein the adjacent cell search means carries out adjacent cell search at a time of activation of the apparatus, when quality of communication with the base station is reduced, or when there is a free area in a time division multiple access frame.

14. The radio communication apparatus as claimed in claim 11, wherein the adjacent cell search means carries out a reception process of the control channel from the adjacent cell at a reception timing which is determined from the timing offset value included in the adjacent cell information acquired by the adjacent cell information acquisition means.

15. The radio communication apparatus as claimed in claim 11, wherein the adjacent cell information acquisition means acquires adjacent cell information that is transmitted included in the control channel.

16. The radio communication apparatus as claimed in claim 11, wherein the adjacent cell information acquisition means requests the base station to transmit the adjacent cell information in response to a decrease in quality of communication with the base station.

17. A radio communication method for operation as a mobile station under a radio communication environment where intra-cell communication is carried out by means of a time division multiple access system, the method comprising:

an adjacent cell search step for searching an adjacent cell;

an adjacent cell information notification step for notifying a base station of the adjacent cell information acquired through the adjacent cell search; and

an adjacent cell information acquisition step for acquiring the adjacent cell information from the base station.

18. The radio communication method as claimed in claim 17, wherein

a base station within each cell transmits a control channel including intra-cell control information at a time division multiple access frame period within the cell;

the adjacent cell search step tries reception of a control channel transmitted by an adjacent cell; and

the adjacent cell information notification step notifies the base station of adjacent cell information acquired through the adjacent cell search and including a timing offset value of time division multi access frames of its own cell and the adjacent cell.

19. A computer program described in computer-readable form to make a computer execute a process of operation as a base station under a radio communication environment where intra-cell communication is carried out by means of a time division multiple access system, the program comprising:

an adjacent cell information reception step for receiving adjacent cell information notified by each mobile station within a cell;

an adjacent cell information management step for managing the received adjacent cell information; and

an adjacent cell information provision step for providing an adjacent cell information stored in the adjacent cell information management step to a mobile station within the cell.

20. A computer program described in computer-readable form to make a computer execute a process of operation as a mobile station under a radio communication environment where intra-cell communications are carried out by means of a time division multiple access system, the program comprising:

an adjacent cell search step for searching an adjacent cell;

an adjacent cell information notification step for notifying a base station of the adjacent cell information acquired as a result of the adjacent cell search; and

an adjacent cell information acquisition step for acquiring the adjacent cell information from the base station.