Patent ID: 7336154
Filing Date: 2008-02-26
Classification: G06K

Abstract:
1. A method of selecting one or more transponders from a plurality of transponders by a base station, said method comprising the following selection steps: a) generating, respectively in each respective transponder of said plurality of transponders, a respective random number bit sequence comprising random bit values; b) providing, respectively in each said respective transponder, an identification bit sequence comprising said random number bit sequence of said respective transponder; c) transmitting bit-by-bit a selection bit sequence comprising selection bit values, from said base station to said plurality of transponders; d) comparing bit-by-bit, respectively in each said respective transponder, corresponding bits of said identification bit sequence of said respective transponder with corresponding bits of said selection bit sequence, wherein said comparing is carried out using a predetermined comparison criterion to provide a comparison result; e) in each said respective transponder, respectively allocating to a transponder selecting indicator bit for said respective transponder a transponder selecting indicator bit value according to and depending on said comparison result; f) respectively selecting one or more of said transponders in response to and depending on said transponder selecting indicator bit value allocated to said transponder selecting indicator bit of each said transponder respectively; g) prior to said respective bit-wise comparing of said corresponding bit of said identification bit sequence of said respective transponder with said corresponding bit of said selection bit sequence in said step d), transmitting a respective bit value of said respective corresponding bit of said identification bit sequence from said respective transponder to said base station; and h) generating at least one of said selection bit values of said selection bit sequence in said base station in response to and depending on at least one said respective bit value of said respective corresponding bit of said identification bit sequence received by said base station from said respective transponder.