Characteristics of Radiation Noise from an LED Lamp and Its Effect on the BER Performance of an OFDM System for DTTB

The characteristics of radiation noise from an LED lamp and its effect on the bit error rate (BER) performance of an orthogonal frequency-division multiplexing (OFDM) system for digital terrestrial television broadcasting (DTTB) are investigated. The waveform and frequency spectrum of radiation noise from an LED lamp are measured. A sequence of noise pulses is observed, caused by the switching circuit of the LED, and spread over the broadcast band of Japan. The relationship between the radiation noise from the LED lamp and its effect on the BER performance of the OFDM system using 64-quadrature amplitude modulation (64QAM) is evaluated using amplitude probability distribution (APD) measured with various resolution bandwidths. The behavior of the APD of the noise is similar to Gaussian noise when the resolution bandwidth becomes narrow. The BER performance of the OFDM system subjected to the noise of the LED lamp is estimated from the APD results, which agree well with measured results subjected to the LED noise. The characteristics of sequential LED noise are similar to the effect of Gaussian noise on the BER performance of the OFDM system for DTTB. Therefore, the APD measurement is a useful method to estimate the characteristics and effect of noise from an LED lamp on the OFDM system.