| 摘要 |
PROBLEM TO BE SOLVED: To reliably transmit and receive packets with a low gain, while enabling the long distance communication without causing the collision. SOLUTION: The transmit side transmits RTS signals at a low data rate using a nondirectional antenna 206 as it is [S302], and then goes to a waiting state as it is. The receive side receives the RTS signals by a nondirectional antenna 206 [S303], returns CTS signals at a low data rate [S304] after receiving the RTS signals, and switches the antenna to a directional antenna 207 [S305]. The transmit side receives the CTS signals [S306], transmits data packets at a high data rate using the nondirectional antenna 206 as it is [S307], and goes into a waiting state without switching the nondirectional antenna 206. The receive side receives unicast packets sent at a high data rate by the directional antenna [S308]. COPYRIGHT: (C)2005,JPO&NCIPI
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