Résumé: The common backscatter communications (ComBC), widely applied in wireless powered networks such as the RFID systems, exhibit the shortcoming that only a few bits are backscattered at a time due to energy limitation. It is significant to improve energy efficiency in backscatter communications so more data can be delivered within one backscatter. In this article, the energy-efficient dual-codebook based backscatter communications (DBBC) is proposed, which adopts two prefix codebooks shared by the sender and the receiver over a backscatter communication link. With the DBBC, the sender backscatters codewords from which the receiver decodes the original data. Using Energy Consumption Disparity (ECD) between backscattering bits 1 and 0 in the existing backscatter communications, we formulate the optimization problem minimizing energy consumption over the link for the DBBC. Mapping a prefix codebook into a binary tree and performing pruning and expanding operation (PEO) on binary trees, we obtain the solution to the optimization problem, which includes the two energy-efficient codebooks and the other two key parameters for the DBBC. The experiments on wireless identification sensing platform (WISP) show that, under the proposed DBBC, the sender can backscatter data 83% more than the ComBC with the same energy without sacrificing throughput.

Langue: Anglais