| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication system where interference between cells is reduced by permitting a base station in the cell to use a directional antenna to adopt sectoring. SOLUTION: In order to adopt sectoring, a base station in a cell uses a directional antenna. Not only the cell is sectored from the viewpoint of transmission by the directivity of a down link antenna but also orthogonal frequency division multiplex(OFDM) tones adopted in the respective cells are correspondingly made to be orthogonal. Namely, the set of the tones is allocated in the sub- band of frequency band width, which can be used, so that it can be used at the time of transmitting it to the respective sectors in the cell. In a hexagonal cell 601, for example, the tones of the same sub-bands are allocated to all sectors 603, 605 and 607 having the same bearing. The sub-bands allocated to the sectors 603, 605 and 607 are periodically changed between the sub-bands that can be used in a band where the whole can be used. |
