A Crystal-Less Self-Synchronized Bit-Level Duty-Cycled IR-UWB Transceiver System

A self-synchronized dual-band OOK IR-UWB transceiver system for short-range, low-data rate sensor networks is demonstrated. The transceiver system utilizes asynchronous non-coherent energy detection coupled with a novel pulse-coupled injection-locking scheme to synchronize transceivers throughout the network at nanosecond-scale precision. The pulse-coupled synchronization scheme compensates for intrinsic frequency variation so that all timing in the system can be derived from an integrated relaxation oscillator operating at a nominal frequency of 150 KHz. A low-jitter PLL and simple combinational logic is used for timing generation and control. The system is duty cycled between the expected arrival times of the sync and data pulses, allowing a demonstrated average RF duty cycle of less than 1% while being able to maintain synchronization for nearly 1 million cycles. Total measured system power consumption is 119 μW while actively communicating with 1200 bit packets. The transceiver was designed in a 90 nm IBM CMOS process and occupies 1.7 mm² of active area.