Radio communication system

• US 6,141,335 A
• Filed: 12/04/1997
• Issued: 10/31/2000
• Est. Priority Date: 12/06/1996
• Status: Expired due to Fees

• Current Assignee: Hitachi Communication Technologies, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Kuwahara, Mikio, Hanaoka, Seishi, Doi, Nobukazu, Uta, Takaki
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): HO, DUC CHI
• Application Number:
  US08/985,484
• Time in Patent Office: 1,062 Days
• Field of Search: 370/328, 370/324, 370/331, 370/342, 455/442, 455/509, 455/513, 455/524, 455/562, 342/428, 342/449, 342/457
• US Class Current: 370/342
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

In a cellular radio communication system including a plurality of base stations and a plurality of terminals in which one cell is divided into a plurality of sectors, each of the base stations transmits and receives control information by an omnidirectional beam and transmits and receives traffic information by a directional beam. Alternatively, each of the base stations transmits and receives control information by a directional beam with a time difference of the same control information in a plurality of sectors within one cell and transmits and receives traffic information by a directional beam.

Claims

1. A cellular radio communication system comprising a plurality of base stations and a plurality of terminals and in which one cell is divided into a plurality of sectors, wherein each of said plurality of base stations transmits and receives control information by a directional beam with a time difference of the same information in a plurality of sectors within one cell and transmits and receives traffic information by a directional beam, wherein said directional beam for said control information is transmitted in such a manner that it is rotated when said base station is seen from above, and wherein channels are multiplexed by a CDMA system, wherein said CDMA system shall be in accordance with the TIA/EIA/IS-95-A and said control information are a pilot signal, call connection information, broadcast information and paging information, and wherein a plurality of base stations which are located close to each other transmit pilot signals with a synchronization of transmission angles of said pilot signals, wherein said plurality of base stations which are located close to each other are ranked according to signal phase order, each said base station receives the adjacent pilot signal of higher order signal phase and transmits a pilot signal in the direction opposite to the direction from which said pilot signal is received, thereby synchronizing transmission angles of pilot signals of a plurality of base stations.

2. A cellular radio communication system comprising a plurality of base stations and a plurality of terminals and in which one cell is divided into a plurality of sectors, wherein each of said plurality of base stations transmits and receives control information by a directional beam with a time difference of the same information in a plurality of sectors within one cell and transmits and receives traffic information by a directional beam, wherein said directional beam for said control information is transmitted in such a manner that it is rotated when said base station is seen from above, and wherein channels are multiplexed by a CDMA system, wherein said CDMA system shall be in accordance with the TIA/EIA/IS-95-A and said control information are a pilot signal, call connection information, broadcast information and paging information, and wherein a plurality of base stations which are located close to each other transmit pilot signals with a synchronization of transmission angles of said pilot signals, wherein each terminal includes more than two receivers, searches cells of other base station than a present communicated base station, memorizes and reports an arrival time and a cycle of a pilot signal from other base station than said presently communicated base station to said presently communicated base station and said presently communicated base station controls a transmit power in accordance with said arrival time and said cycle of said pilot signal.

3. A cellular radio communication system comprising a plurality of base stations and a plurality of terminals and in which one cell is divided into a plurality of sectors, wherein each of said plurality of base stations transmits and receives control information by a directional beam with a time difference of the same information in a plurality of sectors within one cell and transmits and receives traffic information by a directional beam, wherein said directional beam for said control information is transmitted in such a manner that it is rotated when said base station is seen from above, and wherein channels are multiplexed by a CDMA system, wherein said CDMA system shall be in accordance with the TIA/EIA/IS-95-A and said control information are a pilot signal, call connection information, broadcast information and paging information, and wherein a plurality of base stations which are located close to each other transmit pilot signals with a synchronization of transmission angles of said pilot signals, wherein each terminal includes more than two receivers, searches cells of other base station than a presently communicated base station, memorizes and reports a phase difference between a pilot signal of said presently communicated base station and a pilot signal of said base station other than said presently communicated base station to said presently communicated base station, and said presently communicated base station does not transmit traffic information during a time corresponding to said phase difference.