NFC tags anti collision

how to identify NFC tags when there are more than one tag in the field of NFC reader is there any algorithm for this .if yes could anyone post the link here

Yes, there are algorithms. Each algorithm depends on the type of card. Is it ISO15693, is it ISO14443 TypeA, ISO14443 TypeB, Felica, etc. You can find the algorithm in the corresponding ISO document for the specific tag type, but the first thing you must know is the tag type.

NFC-Specification is downloadable from ECMA
http://www.ecma-international.org/pu...T/Ecma-340.pdf
http://www.ecma-international.org/pu...T/ECMA-352.pdf