Cellular system and frequency carrier allocation method

DETAILED DESCRIPTION It is an object of the present invention to provide a cellular system which can increase the utilization efficiency of frequency carriers and a frequency carrier arrangement method for the system.
It is another object of the present invention to provide a cellular system which can rearrange frequency carriers in accordance with a change in the ratio of traffics in the uplink and downlink directions and the like.
In order to achieve the above objects, according to the present invention, there is provided a frequency carrier arrangement method for a cellular system made up of a plurality of first base stations having first communication areas, a plurality of second base stations having second communication areas, and a plurality of mobile stations for performing radio communications with the first and second base stations, comprising the steps of arranging first and second frequency bands to which frequency carriers used for uplink and downlink communications between the first and second base stations and the mobile stations such that frequency bands do not overlap, arranging a first frequency carrier group constituted by at least one frequency carrier and a second frequency carrier group constituted by at least one frequency carrier different from the first frequency carrier group in the first frequency band, arranging a third frequency carrier group constituted by at least one frequency carrier and a fourth frequency carrier group constituted by at least one frequency carrier different from the third frequency carrier group in the second frequency band, performing uplink and downlink communications by using frequency carriers belonging to the second and third frequency carrier groups at the first base station, and performing uplink and downlink communications by using frequency carriers belonging to the fourth and first frequency carrier groups at the second base station.