Patent ID: 8009616

Claim:
A radio access method for use in a radio system including a radio terminal and a radio base station having an array antenna with a plurality of antenna elements and capable of transmitting directional multibeam from said array antenna of said radio base station to said radio terminal in a state where a different orthogonal code series is allocated to each of a plurality of directional beams, said radio access method comprising: on the radio base station, transmitting a directional multibeam of a downlink physical channel to said radio terminal, on said radio terminal, receiving the directional multibeam from said radio base station; obtaining correlation between the orthogonal code series of the received directional multibeam and an orthogonal code series stored in said radio terminal; determining an orthogonal code series having a highest correlation; and transmitting orthogonal code series identification information identifying the determined orthogonal code series to said radio base station by superimposing the orthogonal code series identification information on information used for retransmission control between said radio base station and said radio terminal.