An apparatus and method for assigning subchannel(s) for communication between frequency agile mobile station(s) and a frequency agile base station. A received power level may be identified for each subcarrier in a set of subcarriers available for data transmission. A minimum power level needed to establish communications may be allocated. A detection threshold set to avoid interference with other devices currently transmitting on the set of subcarriers may be determined using the minimum uplink power level. A subset of subcarriers not already assigned may be selected where each subcarrier in the subset of subcarriers has a received power level that is less than the detection threshold. A subchannel that satisfies a bandwidth requirement may be formed where the subchannel consists of selected subcarriers in the set of subcarriers available for data transmission between the frequency agile mobile station(s) and the frequency agile base station.