Base station transmission power control system, mobile station and base station
First Claim
1. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals, said mobile station being capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations in the system, said mobile station comprising;
- a primary base station detecting means for detecting primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group;
a base station transmission power control signal determining means for setting a base station transmission power control signal indicating to increase or decrease a transmission power; and
a control signal transmitting means for transmitting primary base station information detected by said primary base station detecting means and said base station transmission power control signal determined by said base station control signal determining means to said base station group in soft hand over.
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Accused Products
Abstract
In soft hand over in a code division multi access mobile radio communication system, interference in a down link caused by transmission from a plurality of base stations for one mobile station, can be restricted. Control of transmission power is performed according to command from the mobile station only in the base station serving as a primary base station which has minimum propagation loss with the mobile station during soft hand over, and the base stations other than the primary base station perform transmission with restricting output. In comparison with the transmission power control performed by the conventional plural base station transmission, interference for the peripheral mobile station can be reduced to achieve higher down link capacity. Also, upon restricting transmission power of the base station other than the base stations having small propagation loss with the mobile station among base station group in soft hand over, by moderately attenuating the transmission power instead of restricting abruptly, degradation of the reception quality can be prevented when error is caused in selection of the base station.
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Citations
20 Claims
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1. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals, said mobile station being capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations in the system, said mobile station comprising;
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a primary base station detecting means for detecting primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group; a base station transmission power control signal determining means for setting a base station transmission power control signal indicating to increase or decrease a transmission power; and a control signal transmitting means for transmitting primary base station information detected by said primary base station detecting means and said base station transmission power control signal determined by said base station control signal determining means to said base station group in soft hand over. - View Dependent Claims (2, 3, 4)
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5. A base station transmission power control system in a code division multi access cellular mobile radio communication system, said communication system comprising:
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a plurality of base stations respectively announcing unique pilot signals and a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations, said mobile station detects a primary base station, a reception level of a pilot signal received from the primary base station is maximum level among reception levels of pilot signals received from respective base stations in soft hand over base station group, said mobile station sets one of a power increasing symbol and a power decreasing symbol in said transmission power control bit, and transmits said transmission power control bit and primary base station information to said soft hand over base station group, and each base station of said soft hand over base station group receives a transmission power control signal which includes said primary base station information, and restricts a transmission power of a transmission signal to the mobile station in the event that said primary base station information is not consistent with a base station information of said base stations. - View Dependent Claims (6, 7, 8, 9)
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10. A communication control method in a code division multi access cellular mobile radio communication system, said communication system comprising a plurality of base stations respectively announcing unique pilot signals and
a mobile station which is capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations, said communication control method comprises: -
a step of detecting a primary base station among said base stations, a reception level of a pilot signal received from the primary base station which is the maximum level among reception levels of pilot signals received from respective base stations in said soft hand over base station group; a step of setting one of a power increasing symbol and a power decreasing symbol in a transmission power control bit; and a step of transmitting said transmission power control bit and primary base station information to said soft hand over base station group. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A mobile station in a code division multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals, said mobile station being capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations in the system, said mobile station comprising;
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a primary base station detecting unit which detects primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group; a base station transmission power control signal determining unit which sets a base station transmission power control signal indicating to increase or decrease a transmission power; and a control signal transmitting unit which transmits primary base station information detected by said primary base station detecting means and said base station transmission power control signal determined by said base station control signal determining means to said base station group in soft hand over.
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17. A mobile station in a code divisional multi access cellular mobile radio communication system comprising a plurality of base stations respectively announcing unique pilot signals, said mobile station being capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations in the system, said mobile station comprising:
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a reception quality detecting unit which detects a communication reception quality, a primary base station detecting unit which detects primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group; a base station transmission power control signal determining unit which sets a base station transmission power control signal indicating to increase or decrease a transmission power; and a control signal transmitting unit which transmits a primary base station information detected by said primary base station detecting unit and said base station transmission power control signal determined by said base station control signal determining unit to said base station group in soft hand over; wherein said control signal transmitting unit transmits said base station transmission power control signal determined by said base station control signal determining unit to the base station group in soft hand over or intermittently transmits the primary base station information detected by said primary base station detecting unit and said base station transmission power control signal determined by said base station control signal determining unit to said base station group in soft hand over.
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18. A communication control method in a code division multi access cellular mobile radio communication system, said communication system comprising a plurality of base stations respectively announcing unique pilot signals, said mobile station being capable of simultaneously establishing connection with a soft hand over base station group comprising some of base stations out of said plurality of base stations in the system, said control method comprising the steps of:
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detecting a primary base station which transmits a pilot signal of the maximum reception level at said mobile station among received pilot signals from said base stations in said soft hand over base station group; setting a base station transmission power control signal indicating to increase or decrease a transmission power; and transmitting primary base station information corresponding to said detected primary base station and said base station transmission power control signal to the soft hand over base station group. - View Dependent Claims (19, 20)
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Specification