The widely-used EPC Gen2 protocol for backscatter communication is inefficient in dealing with transferring a large amount of buffered data to RFID reader.Furthermore,it is not adaptable to dynamic energy harvesting and channel condition.In order to solve these problems,firstly,the original logic of EPC Gen2 protocol was optimized by adopting burst transmission to reduce the idle slots and introducing erasure code to avoid waiting for the ACK.Secondly,the expression of the throughput under specific energy harvesting and channel conditions was derived.Then the throughput maximization problem was formulated,which was solved by the method of exhaustion.The optimal combination of the frame length,the number of redundant frames and the charging time were obtained.Thirdly,a dynamic frame and charging time adaptation (DFCTA) scheme was proposed,which increased or decreased the frame length and the number of redundant frames at runtime based on the throughput measurement at the reader.Finally,simulations were conducted under different energy harvesting and channel conditions to evaluate the frame length,the number of redundant frames,the achieved throughput and the energy cost of the proposed DFCTA scheme.Simulation results showed that by DFCTA scheme,the throughput performance was remarkably improved compared with current fixed-frame-length scheme in EPC Gen2 protocol and it was quite close to the theoretical optimum.Consequently,the optimization of the protocol logic and the proposed DFCTA scheme were proved to be effective in improving the throughput performance.
