Patent ID: 7801563

Claim:
A radio base station apparatus for transmitting signals to a plurality of user equipments with time division multiplexing using a downlink shared channel shared by the plurality of user equipments and receiving signals from each user equipment via an uplink dedicated channel, comprising: a plurality of antenna elements for transmitting and receiving radio signals; a detection unit for detecting information about an uplink dedicated channel corresponding to each user equipment from signals received via said plurality of antenna elements; a directivity control unit for calculating directivity information about directivity of transmission beam for each user equipment based on the information detected by said detection unit; a storage unit for storing directivity information calculated by said directivity control unit; a transmission unit for extracting from said storage unit directivity information corresponding to a destination user equipment of data to be transmitted for each time division multiplexing time slot and transmitting signals with the directivity according to the extracted directivity information; and a channel selection unit for selecting, based on traffic volume of transmission data to a user equipment, a downlink dedicated channel or the downlink shared channel as a communication channel for transmitting a signal to the user equipment, wherein the directivity is calculated based on the information detected in a high speed dedicated control channel while data is transmitted to the user equipment via the downlink shared channel, the directivity is calculated based on the information detected in a dedicated control channel while data is not transmitted to the user equipment via the downlink shared channel, and when a communication channel for transmitting a signal to a first user equipment is switched from the downlink dedicated channel to the downlink shared channel by said channel selection unit, said directivity control unit determines directivity of transmission beam for transmitting a signal via the downlink shared channel according to lastly detected reception power of an uplink channel corresponding to the downlink dedicated channel before the channel switching, until reception power of an uplink channel corresponding to the downlink shared channel after the channel switching is obtained by said detection unit.