An improved accelerated frame slotted aloha (afsa) algorithm for tag   collision in rfid
  The efficiency of tag identification in an RFID system can be low down due to the tag collision problems. the tag collision problem occurs when a reader try to read multiple tags in an interrogation zone. as a result the reader does not identify the tag correctly. that causes a loss of information or data interference. to solve such kind of issues a series of aloha based algorithm and binary search algorithm have beed proposed. the most simple popular and good giving performance algorithm are aloha based anti-collision algorithms. in this paper we present a new variation in accelerated slotted aloha afsa. our proposed algorithm by using the bitmaps and avoids wastages in bit times due to idleness and collided slots reduce the tag reading time. the simulation result shows that afsa can significantly reduce the average tag reading time with respect to the base protocols and achieve high tag reading rates under both static and mobile setting. 
Tanveer Ahmad, Yan tian feng
cs.NI