LTE-like Paging and Synchronization for Ambient Backscatter.

The continuous and ubiquitous nature of LTE traffic makes it advantageous as a backscatter carrier. However, existing backscatter works ignore the importance of being LTE-like, resulting in incompatibility with the standard and inability to access LTE services. We observe that achieving LTE-like requires a service initiation mechanism, that is, paging and accurate downlink synchronization. To this end, we present LTElike, a novel backscatter design that can page tags to initiate LTE service requests. Specifically, we page our tag using the form of amplitude modulation, enabling the ultra-low-power tag to receive paging and wake up. Further, we design an accurate synchronization strategy combining detection and template matching based on correlation, which improves the accuracy to single symbol level. We prototype LTElike using FPGAs, SDR LTE eNBs and UEs. The evaluation results show that the paging identification rate is as high as 100%, and the mean synchronization error of LTElike is 17x better than the counterpart of LScatter.