Base station and mobile communication system utilizing the same

• US 20050083881A1
• Filed: 01/23/2003
• Published: 04/21/2005
• Est. Priority Date: 01/23/2002
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ohwada, Hideki
• Granted Patent: US 7,672,646 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

A hardware is used to perform an SSDT processing, thereby avoiding performance degradation than otherwise would occur due to load increase caused by a software processing, and thereby realizing a base station that can instantaneously perform a transmission control and provide a high speed site selection. In order to perform a site selection diversity power control (SSDT) for the purpose of reducing the amount of interference that would be caused by transmitting the same data to a plurality of cells or antennas during soft-handover, an encode processing part (1) is used to add a transmission control bit to the transmitted data. In response to this transmission control bit, a transmission control signal selecting circuit (206) selects a transmission control signal of destination. An output control circuit (207) receives, as its inputs, a transmission spread signal and the transmission control signal to perform an output control and instantaneously perform a transmission control, thereby realizing a high-speed site selection.

Claims

1-12. -12. (canceled)

13. A base station having a plurality of antennas corresponding to sectors, which is used in a CDMA (Code Division Multiple Access) communication system for performing a site selection diversity control during soft-handover that the base station and a mobile terminal perform communication through more than one sector,

said base station comprising a transmission control signal generator for adding a transmission control signal showing if the transmission can be realized or not for said plural antennas to the transmission data;

and

transmission controller for performing on-off control of said transmission data to said antennas in response to this transmission control signal,

wherein said transmission control signal generator generates said control signal for each symbol of said transmission data, respectively, and includes a multiplexer for time division multiplexing said symbol and said control signal corresponding to said symbol and outputting them.

14. The base station according to claim 13, wherein said transmission control signal generator generates said transmission control signal according to a receiving quality of a transmission pilot signal from each of said antennas at said mobile terminal.

15. The base station according to claim 14, wherein said control signal indicates that the transmission can be performed only to the antenna with the best receiving quality from among said antennas and the transmission cannot be performed to other antennas.

16. The base station according to claim 13, comprising a spread processor for performing spread processing of said transmission data separately for said plural antennas,

wherein said transmission controllor separates said transmission data and said transmission control signal and performs the output control of said corresponding spread processor in response to this separated transmission control signal for the corresponding antenna.

17. The base station according to claim 13, comprising a plurality of spread processors for performing the spread processing of said transmission data and output destination selector for freely selecting said antenna as the output destination of said spread processor;

wherein said transmission controller separates said transmission data and said transmission control signal and performs output control of said spread processor corresponding to the output destination that is selected by said output destination selector in response to the separated transmission control signal for the corresponding antenna.

18. A mobile communication system, particularly, a CDMA (Code Division Multiple Access) communication system for performing a site selection diversity control during soft-handover that a base station having a plurality of antennas corresponding to sectors and a mobile terminal communicating to said base station perform communication through more than one sector,

said base station comprising a transmission control signal generator for adding a transmission control signal showing if the transmission can be realized or not for said plural antennas to the transmission data;

and

a transmission controllor for performing on-off control of said transmission data to said antennas in response to this transmission control signal,

wherein said transmission control signal generator generates said control signal for each symbol of said transmission data, respectively, and includes a multiplexer for time division multiplexing said symbol and said control signal corresponding to said symbol and outputting them.

19. The mobile communication system according to claim 18, wherein said mobile terminal measures the receiving quality of the transmission pilot signal from each of said antennas and said transmission control signal generator generates said transmission control signal according to said receiving quality.

20. The mobile communication system according to claim 19, wherein said control signal indicates that the transmission can be performed only to the antenna with the best receiving quality from among said antennas and the transmission cannot be performed to other antennas.

21. The mobile communication system according to claim 18, wherein said base station comprises a processor for spread processing of said transmission data separately for said plural antennas;

wherein said transmission controller separates said transmission data and said transmission control signal and produces an output for controlling said corresponding spread processor in response to the separated transmission control signal for the corresponding to said antenna.

22. The mobile communication system according to claim 18, wherein said base station comprises a plurality of spread processors for spread processing of said transmission data and an output destination selector for freely selecting said antenna as the output destination of said spread processor;

wherein said transmission controllor separates said transmission data and said transmission control signal and produces an output for controlling said spread processor corresponding to the output destination that is selected by said output destination selector in response to the separated transmission control signal for the corresponding antenna.