Mobile communications system, radio controller, base station, and method of controlling transmission power
AssigneeNtt Docomo, Inc.
InventorsTakuya Sato, Minami Ishii, Masafumi Usuda, Takehiro Nakamura
Life of this patent
Estimating the term…
Abstract
A mobile communications system including a plurality of base stations, and a radio controller controlling each base station is disclosed. The radio controller sets for each base station an offset value based on the communications quality at that base station so as to set a target transmission power value of a downlink from the base station to a mobile station, enabling an appropriate controlling of the transmission power of the downlink using a power-balancing control.
Claims12
A mobile communications system, comprising a plurality of base stations, and a radio controller which controls each of said base stations,
- wherein each said base station comprises,
- a transmission power value reporting unit configured to report to said radio controller a downlink transmission power value and a communications quality of a downlink from said base station itself to a mobile station, and,
- said radio controller comprises:
- a cell-determining unit configured to determine, out of cells each serviced by one of said base stations, a cell having a good communications quality;
- a reference-value determining unit configured to determine, as a reference value, a downlink transmission power value of the base station which services the determined cell;
- an offset-value setting unit configured to set, based on said communications quality, an offset value corresponding to each said base station;
- a target-value setting unit configured to set, based on said reference value and said corresponding offset value, a target value corresponding to each said base station;
- and
- a target-value reporting unit configured to report said target value to said base station;
- and
- each said base station further comprises,
- a transmission power control unit configured to control the transmission power value of the downlink from said base station itself to said mobile station so as to cause the transmission power value to approach said target value.
A radio controller which controls a plurality of base stations configuring a mobile communications system, comprising:
- a transmission power value obtaining unit configured to obtain a downlink transmission power value and a communications quality, reported from each of said base stations, of a downlink used in communications from said base station to a mobile station;
- a cell-determining unit configured to determine, out of cells each serviced by one of said base stations, a cell having a good communications quality;
- a reference-value determining unit configured to determine a downlink transmission power value of a base station which services the determined cell, as a reference value of the downlink transmission power value at each said base station;
- an offset-value setting unit configured to set, based on said communications quality, an offset value corresponding to each said base station;
- a target-value setting unit configured to set, based on said reference value and said corresponding offset value, a target value corresponding to each said base station;
- and
- a target-value reporting unit configured to report said target value to each said base station.
A base station which configures with one or more other base stations a mobile communications system, comprising:
- a transmission power value reporting unit configured to report a transmission power value and a communications quality of a downlink used in communications from said base station itself to a mobile station, to a radio controller which controls each of said base stations configuring said mobile communications system;
- a target-value obtaining unit configured to obtain a target value, reported from said radio controller, as the transmission power value of the downlink at, out of said base stations configuring said mobile communications system, a base station servicing a cell having a good communications quality;
- and
- a transmission power control unit configured to control so as to cause the transmission power value of the downlink from said base station itself to said mobile station to approach said target value.
A method of controlling, in a mobile communications system comprising a plurality of base stations, and a radio controller which controls said base stations, a transmission power value of each of said base stations,
- wherein said each base station reports the downlink transmission power value and a communications quality of a downlink from said base station itself to a mobile station;
- said radio controller determines, out of cells each serviced by one of said base stations, a cell having a good communications quality;
- said radio controller determines, as a reference value, the downlink transmission power value of a base station which services the determined cell;
- said radio controller sets, based on said communications quality, an offset value corresponding to each said base station;
- said radio controller sets, based on said reference value and said corresponding offset value, a target value corresponding to each said base station;
- said radio controller reports said corresponding target value to each said base station;
- and
- each said base station controls the transmission power value of the downlink from said base station itself to said mobile station so as to cause the transmission power value to approach said target value.
Dependencies are inferred from the claim text.