Patent ID: 8311026

Claim:
A mobile communication system including multiple cells having different system bandwidths, wherein in a cell having a system bandwidth wide enough to allow a random access channel from a user apparatus and an uplink shared data channel from another user apparatus to be frequency-division multiplexed in a same subframe, an uplink control channel unattached to the uplink shared data channel and the random access channel are frequency-division multiplexed in the same subframe, and in a cell that does not have a system band wide enough to allow a random access channel from a user apparatus and an uplink shared data channel from another user apparatus to be frequency-division multiplexed in a same subframe, an uplink control channel unattached to the uplink shared data channel and the random access channel are time-division multiplexed, and the random access channel is transmitted for a transmission period of a downlink signal not being required to feed acknowledgement information indicative of positive acknowledgement or negative acknowledgement back to a base station apparatus.