This proposal seeks to perform fundamental cross-disciplinary cross-layered research into the design of a network stack for sensor devices that use backscatter communication. Backscatter communication is particularly attractive for single-hop sensor network deployments since communication is powered by the reader, thereby resulting in tremendous reduction in power consumption compared to devices with active radios (e.g. 802.15.4). Despite these benefits, protocols designed for backscatter are ill-designed for sensor workloads. The existing backscatter communication stack, EPC Gen 2, is optimized for supporting large numbers of simple passive tags, that each need to transfer a small amount of data (their unique identifier). While such a model may be appropriate when RFIDs are deployed in retail stores, sensors require a different model where there are a few or moderate number of tags which need to transfer a significant amount of sensed data during contact events with a reader.
This proposes outlines a fundamentally new backscatter communication stack that is designed for next-generation sensors that use passive rather than active radios. The stack will be build on an extensive measurement-driven study of backscatter communication including an understanding of channel quality metrics, link asymmetry, spatial and temporal propagation, and harvesting characteristics. Based on this study, we will design a network stack for backscatter communication that replaces the EPC Gen 2 stack with novel methods for mobility detection, rate adaptation, channel selection, bulk transfer, and energy management.
Our research will directly impact the design, development, and deployment of next-generation sensor networks that can operate for longer durations or use smaller power sources. This can directly translate into lower total operational costs by lowering the overhead of replacing batteries. The research and teaching that will flow from the project will impact students across the Five Colleges, of which UMass Amherst is a part. The Five Colleges includes two all-women's colleges, Smith and Mount Holyoke, whose students can enroll in courses taught at UMass because of the consortium's cross-registration policy.