Fully-Coherent Reader With Commodity SDR for Gen2 FM0 and Computational RFID

There has been a continuously growing interest in radio frequency identification (RFID) and more recently, in computational RFID, i.e. battery-less sensors that piggyback sensed information, rather than a constant ID bit stream, utilizing Gen2, the physical layer of commercial RFID systems. This work offers a complete software-defined radio (SDR) reader with 1) coherent detection without rate degradation, by exploiting already present preambles in Gen2; 2) full exploitation of FM0 line coding memory in Gen2 tags; 3) careful handling of symbol synchronization and departure of commercial tags from nominal bit duration; and 4) implementation and testing of Gen2 in a commodity SDR, utilizing a single transceiver card. Continuing recent work, this contribution offers an updated prototyping tool that could further unlock the potential of computational RFID and relevant battery-less sensor networks.