A Study on the Adaptive RF Front-End for Low Power Consumption ISDB-T Receiver

Abstract

This paper proposes an adaptive RF (radio frequency) front-end based handheld DTTB (Digital Terrestrial Television Broadcasting) receiver, which is capable of reducing average power consumption. Although OFDM (orthogonal frequency division multiplex), which is exploited as a physical layer transmission scheme of Japanese DTTB standard, ISDB-T (Integrated Services Digital Broadcasting for Terrestrial), requires the low NF (noise figure) and wide dynamic range LNA (low noise amplifier) at the first stage of RF (radio frequency) front-end circuit, it requires higher power consumption to design LNA with lower NF and wider dynamic range characteristics. On the other hand, the power consumption for handheld DTTB receiver is strictly limited due to its battery size. In order to reduce the power consumption, the proposed adaptive RF front-end uses two LNAs having different NF and power consumption characteristics. One of the LNAs gives lower NF but higher power consumption than the other one. In order to minimize the power consumption while maintaining the performance, the RF front-end chooses either one of the LNAs depending on the instantaneous BER (bit error rate) estimated from the modulation error ratio (MER), multipath delay spread, and maximum Doppler shift as well as the transmission mode and modulation format. Computer simulation result shows that the proposed adaptive RFfront-end is capable of reducing the power consumption in a multi-path fading environment.