Patent ID: 7787906
Filing Date: 2010-08-31
Classification: H04W,Y02D

Abstract:
1. A radio base station comprising: a transmission buffer for dividing broadcast information that is to be transmitted to mobile stations into data frames and storing said data frames; a broadcast encoding means for encoding data frames that have been stored in said transmission buffer for transmission by a broadcast transmission method; a reception means for receiving a resend request signal for requesting the resending of said data frames; a decoding means for decoding a resend request signal that has been received by said reception means; a resend control means for controlling the output of data frames for which resending has been requested from said transmission buffer as resending data frames based on a resend request signal that has been decoded by said decoding means; an individual transmission encoding means for encoding for transmission by a unicast transmission method that uses individual channels for said resending data frames; a transmission power calculation means for both calculating the transmission power of said resending data frames to said mobile station by said unicast transmission method based on a resend request signal that has been received by said reception means, and for calculating the transmission power of said data frames by said broadcast transmission method such that the sum of the transmission power of the resending data frames and the transmission power of said data frames by said broadcast transmission method is minimized, and moreover, such that said sum does not fall below a reference value that depends on the dynamic range of the broadcast channel of said radio base station; and a transmission means for transmitting to said mobile station data frames that have been encoded by said broadcast encoding means or resending data frames that have been encoded by said individual transmission encoding means by the transmission power that has been calculated by said transmission power calculation means, wherein the transmission means comprises: transmission power increasing means for increasing the transmission power of said data frames by said broadcast transmission method over a fixed period of time, wherein the transmission power calculation means comprises: first transmission power calculation means for calculating the transmission power of said resending data frames by said unicast transmission method to said mobile station at a first unit of time when the increasing step started; and second transmission power calculation means for calculating the transmission power of said resending data frames by said unicast transmission method to said mobile station at a second unit of time when the increasing step ended, the second unit of time occurring after the first unit of time, wherein, based on whether the sum of the transmission power of the resending data frames and the transmission power of said data frames by said broadcast transmission method calculated at the first unit of time is greater or less than the sum of the transmission power of the resending data frames and the transmission power of said data frames by said broadcast transmission method calculated at the second unit of time, the transmission power of said data frames by said broadcast transmission method is set to either a first transmission power corresponding to a transmission power at the first unit of time or to a second transmission power corresponding to a transmission power at the second unit of time.