Energy-Efficient Parallel Singulation in RFID

Tag collisions impose a significant hindrance to reading rates of Radio Frequency Identification systems. The parallel singulation approach, being a major milestone, clusters tags and autonomously interrogates each cluster in parallel. This technique reduces the number of tags being interrogated at a given time, reducing collisions, and achieves higher reading rates. However, such an approach faces two limitations as the number of clusters increase. The exponential increase in tag responses may hinder tag functionality due to energy spent on communication. Moreover, energy inefficiency is incurred at cluster-heads to process significantly more tag responses. These issues overshadow the promising benefits of employing parallel singulation. In this paper, we remedy such hindrances by proposing energy efficient enhancements to the parallel singulation technique. The essence of these enhancements lies in minimizing an important measure of communication overhead, referred to as tags traffic rate, which indicates the efficiency of interrogation cycles in communicating with all tags without incurring unnecessary overhead. Analyses carried out via simulation demonstrate significant improvements by the proposed schemes in reducing energy consumption of cluster-heads, without posing constraints on tag operations nor incurring significant degradation of reading rates.