Method of communication in a radio frequency identification system

摘要

A first request is transmitted to activate a set of tags in a first state. A first set of data symbols is received. In response to receiving the first set of data symbols, a first acknowledgement symbol transmitted. An acknowledgement symbol is transmitted in response to each subsequent set of data symbols received. A second request is transmitted to activate a second set of tags in a second state when a set of data symbols is not received within a predetermined time, wherein the first state is different from the second state.