| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To enable a plurality of tag communication apparatuses to respectively autonomously control transmission and to obtain a communication opportunity even on the occurrence of interference. <P>SOLUTION: Each communication apparatus includes: a non-response detection section 152 for detecting a communication state with a tag after carrier sensing and start of transmission through a free channel; an interference channel detection section 159 for executing the carrier sensing for all channels to detect a channel with a highest interference level and outputting the channel to an external control apparatus when the non-response detection section 152 detects deterioration in a communication state; a post-transmission stop time setting section 158 for updating and setting a stop time (T<SB>sleep</SB>) after the transmission when the control apparatus informs the post-transmission stop time setting section 158 about an interference causing notice denoting that the tag communication apparatus acts like an interference causing side with another apparatus; and a transmission control section 154 that informs the control apparatus about the channel used at start of transmission to the tag, stops the transmission by the stop time (T<SB>sleep</SB>) after the transmission to the tag, and starts the carrier sensing. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
