Design and implementation of a novel emergency wake-up alert system within a conventional T-DMB service network

Existing emergency alert techniques of terrestrial-digital multimedia broadcasting (T-DMB) and digital audio broadcasting (DAB) can be executed only when the receivers are activated. To overcome the limitation of existing technique, a novel emergency wake-up alert system within a conventional T-DMB service network is proposed. The emergency wake-up alert signal is periodically generated by emergency transmission data unit (ETDU) and then transmitted through the conventional T-DMB/DAB station. After receiving the emergency wake-up alert signal, T-DMB/DAB receiver can be wake-up, activating and result in showing emergency broadcasting contents to people. To obtain frequency efficiency, the emergency wake-up alert signal is overlaid onto the conventional T-DMB frequency band using a direct sequence spread spectrum technique. To assess the performance of the developed ETDU, simple RF transmitter, test receiver and measurement equipment are used. The performance is checked with different values of emergency wake-up alert signal to T-DMB power ratio. The laboratory test results shows that the wake-up alert signal can be transmitted without degrading the existing T-DMB signal quality and can be detected at very low power emergency wakeup alert signal, e.g., as low emergency wake-up alert signal to T-DMB power ratio as -22.2dB.