A 6.5–8.1-GHz Communication/Ranging VWB Transceiver for Secure Wireless Connectivity With Enhanced Bandwidth Efficiency and $\Delta\Sigma$ Energy Detection

This article describes a pulse-based transceiver architecture for mobile authentication with location verification. A time-of-flight (TOF) measurement method is employed as a physical layer countermeasure against relay attack. For bandwidth-efficient pulse transmission with enhanced link margin, frequency-hopping very-wideband (VWB) pulse generation is used. A noncoherent energy detection receiver is designed for TOF-based ranging to have demodulation with low power and low latency. The position of an energy integration window is automatically tracked for both pulse-position modulation (PPM) synchronization and coarse ranging. A ΔΣ energy detection method is proposed to convert ranging information to a 1-bit digital output without requiring asynchronous edge detection (ED). A prototype 6.5-8. 1-GHz VWB transceiver is implemented in 65-nm CMOS. Three channels are realized by having a channel bandwidth of about 400 MHz with a tunable guard band between two adjacent channels. The transceiver achieves the ranging accuracy of 2.0 cm and the demodulation latency of 20 ns, consuming 6.0 mW with a sensitivity of -69 dBm at 5 Mb/s.