Abstract: This paper firstly presented a RFID MAC protocol based on ALOHA and query tree for static tag environment (S-TMAC),then analied the fundamental,process and performance．Secondly,S-TMAC was improved to be M-TMAC which is suitable for mobile tag environment．Protocol structure was defined,and system model was built.Optional reader deployment strategies were put forward．The discussion of the tag identifying time,incidence angle and speed limit was followed．Lastly,simulations indicate that the tag identifying time in M-TMAC and S-TMAC are similar,which is half of ALOHA-based and one-third of tree-based．Furthermore,M-TMAC has low extra system cost,upper tag speed limit and tag incidence angle limit when satisfying default identifying rate and interference rate.

Key words: RFID,Mobile dense tag environment,MAC protocol