| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a high-speed communication user from causing interference with a low-speed communication user and to enable the low-speed communication user to perform reception even if the interference is caused by the high- speed communication user as to a transmission device and a reception device which use a spread spectrum system. SOLUTION: A transmit signal of a user A which communicates at a high speed with large electric power is transmitted by a narrow-directivity antenna 4 so that interference with other users is not caused. A transmit signal to a low-speed communication user 1 is transmitted by a sector antenna 1 and also sent from a narrow-directivity antenna 4 as well in an area wherein the interference by the high-speed communication user A is received. The low-speed communication user receives the signal from the sector antenna 1 and performs an inverse spread process, and also receives the signal from the narrow-directivity antenna 4 and performs an inverse spread process, and they are added and demodulated to increase the substantial receive signal level and make the interference relatively small. Thus, the narrow-directivity antenna is used to accommodate the high-speed communication user and many low-speed communication users without increasing the number of sectors.</p> |
