| 摘要 |
A technique for relaying data between radio nodes comprises: detecting at a first radio node a first signal indicating the number of hops at which a second radio node that transmitted the first signal first detected a second, earlier signal; and deciding whether to transmit said first signal onwards from said first radio node based at least partly on (i) a direction indicator in said first signal 402, and (ii) a comparison of the respective numbers of hops at which said first and second radio nodes first detected said earlier second signal 408/410. At said first radio node a hop-count number is stored, based on a hop-count number indicated in the second signal (a timing signal) detected at the first radio node. A hop count number is only stored at the first radio node in response to first detecting a timing signal in a timing signal sequence. In a disclosed embodiment the first radio node (4b) is mounted on a railcar (2b) of a train including other radio nodes (4b) on other railcars (2b). One radio device (4a) on one of the railcars (2a) functions as a data concentrator/master device. |
