Patent ID: 7697560

Claim:
A radio channel assignment method of employing a multicarrier TDMA (Time Division Multiple Access) system in which communication is performed using a specific carrier in each transmission/reception slot that is obtained through time division, and of assigning a transmission/reception slot and a carrier, as a radio channel, that satisfy desired quality to each mobile station, comprising: a table managing step of managing a frequency management table that includes groups each having a specific number of carriers that form a radio channel so as to be distributed over wide frequency bands; cyclically measuring a received level of interference at the radio channel using an idle slot; and holding results of measurement in order from a carrier at which the received level is lowest, by each of the groups in slots; a radio-channel-candidate deciding step of deciding a slot to be assigned and candidates for a carrier to be assigned in the slot to be assigned based on the frequency management table, when assignment of a radio channel is requested (re-request is also included); a lowest-received-level-carrier selecting step of performing a carrier sense on the candidates for a carrier to be assigned in the slot to be assigned; and selecting a carrier at which the received level is the lowest, out of the candidates; and a radio channel deciding step of comparing the received level at the carrier selected with a specific threshold value that is used to determine whether interference or interruption occurs; and deciding the carrier selected as a carrier to be assigned when the received level is less than the specific threshold value.