A wireless access system is provided which prevents the occurrence of a
hidden terminal problem and minimizes the reduction in throughput. In the
wireless access system, an access point divides terminals into groups
such that terminals in one group cannot recognize radio waves sent from
terminals in another group, and performs communication with the terminals
on a per-group basis. By this, the wireless access system avoids the
occurrence of the hidden terminal problem. RTS/CTS packets used to avoid
the occurrence of the hidden terminal problem are exchanged between the
access point and the terminals on a per-group basis, whereby overhead is
reduced and the reduction in throughput is minimized.