Influence of oscillator phase noise and clipping on OFDM for terrestrial broadcasting of digital HDTV

Abstract

Phase noise causes significant degradation of the performance of a high order quadrature amplitude modulation (QAM) system in conjunction with a n Orthogonal Frequency Division Multiplexing (OFDM) procedure. Moreover, a n OFDM signal has a non constant envelope with large instantaneous amplitude peaks and there will be a need to limit these large variations of the signal. This paper describes a model for oscillator phase noise distortion due to the receiver tuner a n d presents some expressions for amplitude clipping introduced by the nonlinear high power amplifier in the hansmitter and by the automatic gain control in the receiver. Our simulations show the influences on an uncoded and on a trellis-coded system for transmitting Digital High-Definition Television (ITDTV) signals.

Multilevel codes for digital HDTV

“…In case of coding the constraint length of the mother code for the convolutionnl codcrs is chosen to v = 7. For detailed description scc [Sch94]. The results for a single carrier system are almcist the same as for OFDM hccrtuse we didn't ~iicliide t h e degradation due to the g i l d interval in c m nit Error Rates (BER).…”

OFDM peak power reduction by a novel coding scheme with threshold control

“…Additionally, when PAPR is larger than IBO of the HPA, a signal with high PAPR will suffer clipping. Clipping can cause distortion of the signal and deterioration of the system performance [4]. Therefore reduction of PAPR is a main issue in OFDM system.…”