存在非线性失真和相位噪声影响的CP-OFDM与 TDS-OFDM数字电视地面广播传输系统的性能分析

本文概述了数字电视地面广播传输系统中存在的非线性失真和相位噪声影响因素;用模型统一表达了CP-OFDM和TDS-OFDM的OFDM复包络信号;从理论上分析了循环前缀和不断插入的导频训练序列会导致基于CP-OFDM的数字电视地面广播传输系统比在同等的外界条件下的基于TDS-OFDM的数字电视地面广播传输系统具有更低的有效数据符号信噪比水平;详细推导了在非线性失真和相位噪声共同影响下的CP-OFDM系统和TDS-OFDM系统的有效数据符号的统一信噪比表达式;定义并统一表达了在非线性失真和相位噪声共同影响下的CP-OFDM系统和TDS-OFDM系统的性能恶化指标;从理论和计算机仿真两方面比较分析了受到各种不同非线性失真和相位噪声影响的基于CP-OFDM和基于TDS-OFDM的两种不同数字电视地面广播传输系统的性能恶化程度.

Performance Analysis of the CP-OFDM-Based and the TDS-OFDM-Based Digital Television Terrestrial Broadcasting Transmission Systems in the Presence of Nonlinear Distortions and Phase Noise

The performance effects of the digital television terrestrial broadcasting (DTTB)transmission systems caused by the nonlinear distortions and the phase noise are summarized,a uniform model is used to express the complex envelope of orthogonal frequency division multiplexing (OFDM) signal for both the cyclic prefix OFDM(CP-OFDM) and the time domain synchronous OFDM (TDS-OFDM),the fact that cyclic prefix and large amount of training sequences make the CP-OFDM-based DTTB transmission systems have less symbol signal to noise performance than the TDS-OFDM-based DTTB transmission systems is theoretically analyzed,a uniform symbol signal to noise model is thoroughly derived and a performance degradation measure is defined and expressed for both the CP-OFDM system and the TDS-OFDM system in the presence of nonlinear distortions and phase noise,the performance degradations of the CP-OFDM-based and the TDS-OFDM-based DTTB transmission systems in the presence of nonlinear distortions and phase noise are comparatively analyzed both theoretically and by computer simulations.