Abstract: In this work, we study the problem of tag identification in single and multi-reader RFID systems. First, we propose a novel solution to the reader-to-reader collisions and tag collisions in multi-reader systems, using the concept of bit tracking. Second, we explore the bit error types that could occur while using bit tracking. Although bit tracking has a significant contribution on decreasing the identification time, we define a bit error type coined mis-transition that occurs in bit-tracking based protocols only. In addition, we propose a novel technique that tackles mis-transition bit error. RFID systems consist of one or more readers and tags. Our main focus in this work is on battery free RFID tag which is known as passive tags. Passive tags harvest energy from RFID reader and follow the reader’s commands for collision resolving and slot assigning. In the first part of this work, we propose the multi-reader RFID tag identification using bit tracking (MRTI-BT) algorithm which allows concurrent tag identification, by neighboring RFID readers, as opposed to time-consuming scheduling. First, MRTI-BT identifies tags exclusive to different RFIDs, concurrently. Second, the concept of bit tracking and the proposed parallel identification property are leveraged to reduce the identification time compared to the state-of-the-art. Our simulation results exhibit considerable performance improvement with 113% reduction in the identification time, on the average, compared to Season algorithm [1]. iv In the second part of this work, we investigate the bit errors that could occur while using bit tracking. Bit tracking based anti-collision algorithms have gained researchers interest due to their significant contribution in decreasing the identification time. They allow readers to detect the location of collided bits in a collision slot. However, through our deep investigation in bit tracking, we found a new significant bit error called mis-transition which increases the identification time. Mis-transition bit error is different from flipped bit error and it occurs when a reader mistakenly declares collision. In this work, we study and evaluate the effect of mis-transition bit error. In addition, we propose a zero cost algorithm that tackles this problem without using any coding scheme i.e, without adding extra coding bits. Tags may send their ID many times to resolve collision. We make use of the successfully received bits in collision slots to recover mis-transition bit error. Our simulations show the great potential of using repetition gain on recovering bit errors.