Linear Complexity Noncoherent Miller Sequence Detection for Batteryless RFID/IoT

Line coding in batteryless, RF energy harvesting RFID/IoT tags is critical, as it balances two conflicting operations: RF energy absorption (for batteryless powering) and RF energy reflection for backscattering (communication). This work studies Miller line coding, one of the two line codes utilized in commercial RFID, deriving rules for zero-centered or not Miller flat fading signal models. A novel, linear complexity in the sequence length algorithm is proposed for noncoherent Miller sequence detection that can operate within a quarter of a dB from the optimal coherent. Simulation results are corroborated by experimentation in a Gen2 RFID SDR-based testbed. This work provides evidence in favor of more lightweight protocols, free of preamble or pilot bits for future RFID/IoT tags, potentially offering a 10% reading speed gain over the contemporary Gen2 protocol or future short-packet IoT protocols.