Radio base station

1. A radio communication apparatus for transmitting data to a transmitting destination apparatus selected from a plurality of transmitting destination apparatuses using a shared channel and receiving a reception result from the transmitting destination apparatus, said radio communication apparatus comprising:

a storage unit for storing priority sequence information indicative of a prioritized sequence for a plurality of transmitting destination apparatuses such that the radio communication apparatus receives a response signal from the transmitting destination apparatus associated with a high priority via data transmission over the shared channel;

a control unit for selecting one transmission destination apparatus from the plurality of transmitting destination apparatuses, said selecting based at least in part on said priority sequence information and for enabling data transmission to the one transmitting destination apparatus, wherein said selecting performed by the control unit is realized by:

first-selecting the one transmission destination apparatus from a first group included in the plurality of transmitting destination apparatuses, said first group of transmitting destination apparatuses having radio synchronization established;

in the absence of any candidate transmitting destination apparatuses from said first group, second-selecting the one transmission destination apparatus from a second group included in the plurality of transmitting destination apparatuses, said second group of transmitting destination apparatuses having no radio synchronization established; and

in the absence of any candidate transmitting destination apparatuses from said first and second groups, third-selecting the one transmission destination apparatus from the plurality of transmitting destination apparatuses in accordance with a priority sequence for High Speed Downlink Packet Access scheduling; and

a path search unit for searching a path for the one transmitting destination apparatus selected by the control unit.

2. The radio communication apparatus according to claim 1 , wherein the control unit selects the one transmitting destination apparatus identified as an object of the path search by the path search unit from the plurality of transmitting destination apparatuses which transmitting destination apparatus is in a condition that synchronization of the response signal from the transmitting destination apparatus is set up.

3. The radio communication apparatus according to claim 1 , wherein the path search unit refers to an accumulating condition of data transmitted via the shared channel at the time of searching the path for the transmitting destination apparatus.

4. The radio communication apparatus according to claim 1 , wherein the control unit sends a transmission notice to the selected transmitting destination apparatus.

5. The radio communication apparatus according to claim 4 , wherein the control unit performs data transmission control to receive the response signal from the transmitting destination apparatus for which the path search unit searches the path, after completion of the path search for the transmitting destination apparatus.

6. The radio communication apparatus according to claim 1 , wherein the control unit performs said first-selecting in accordance with a priority sequence for High Speed Downlink Packet Access scheduling for said first group, and wherein the control unit performs said second-selecting in accordance with a priority sequence for High Speed Downlink Packet Access scheduling for said second group.

7. The radio communication apparatus according to claim 6 , wherein the path search unit, in response to said third-selecting the transmission destination apparatus from the plurality of transmitting destination apparatuses in accordance with the priority sequence for High Speed Downlink Packet Access scheduling, further performs:

determining whether data exists in the storage unit for transmission to the transmitting destination apparatus having a higher priority in the priority sequence than any other transmitting destination apparatus of said plurality of transmitting destination apparatuses for which data for transmission exists in said storage unit;

when data does not exist for the transmission destination apparatus, searching a path for a transmitting destination apparatus having a highest priority in the priority sequence.

8. The radio communication apparatus according to claim 1 , wherein the path search unit, in response to said third-selecting the transmission destination apparatus from the plurality of transmitting destination apparatuses in accordance with the priority sequence for High Speed Downlink Packet Access scheduling, further performs:

determining whether data exists in the storage unit for transmission to the transmitting destination apparatus having a higher priority in the priority sequence than any other transmitting destination apparatus of said plurality of transmitting destination apparatuses for which data for transmission exists in said storage unit;

when data does not exist for the transmission destination apparatus, searching a path for a transmitting destination apparatus having a highest priority in the priority sequence.

9. A control unit included in a radio communication apparatus for transmitting, by utilizing a shared channel, data to a transmitting destination apparatus selected from a plurality of transmitting destination apparatuses and receiving a reception result from the transmitting destination apparatus, said control unit comprising:

selecting means operable for selecting a transmitting destination apparatus from the plurality of transmitting destination apparatuses as an object of a path search in accordance with transmission control of data utilizing the shared channel, based on priority sequence information indicative of a prioritized sequence for a plurality of transmitting destination apparatuses such that the radio communication apparatus receives a response signal from the transmitting destination apparatus associated with a high priority via data transmission over the shared channel, wherein said selecting performed by the selecting means is realized by:

first-selecting the transmission destination apparatus from a first group included in the plurality of transmitting destination apparatuses, said first group of transmitting destination apparatuses having radio synchronization established;

in the absence of any candidate transmitting destination apparatuses from said first group, second-selecting the transmission destination apparatus from a second group included in the plurality of transmitting destination apparatuses, said second group of transmitting destination apparatuses having no radio synchronization established; and

in the absence of any candidate transmitting destination apparatuses from said first and second groups, third-selecting the transmission destination apparatus from the plurality of transmitting destination apparatuses in accordance with a priority sequence for High Speed Downlink Packet Access scheduling; and

an output means for outputting the information of the selected transmitting destination apparatus.