A radio-frequency-identification (RFID) system includes an RFID tag and an RFID reader, where the RFID reader is configured to communicate with the RFID tag using time-hopped pulse-position modulation and ultra-wideband modulation. The time-hopped pulse-position modulation includes sending from the RFID...http://www.google.de/patents/US20080012688?utm_source=gb-gplus-sharePatent US20080012688 - SECURE RFID BASED ULTRA-WIDEBAND TIME-HOPPED PULSE-POSITION MODULATION
