9. A base station for use in a wireless communication system and arranged to transmit a control channel message, the base station comprising:a configurer configured to configure a plurality of search spaces, each of the plurality of search spaces being configured from a plurality of control channel elements within a subframe by using a pseudo-random function;
a scheduler configure to determine one or more control channel elements to use for transmission of the control channel message within the plurality of search spaces, and
a transmitter configured to transmit the control channel message located in the one or more control channel elements,
wherein, the pseudo-random function is a function based on a sum of a first value and a second value,
wherein the first value is a pseudo-random factor, and the second value is based on an aggregation level and a total of control channel elements in the subframe.