As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliabilit...As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliability by adopting flexible frame structure and advanced forward error correction coding compared with the 1 st generation DTTB systems.In order to increase the flexibility and robustness of the DTTB network,the frequency reuse scheme of factor one(reuse-1)is proposed,where the same RF channel is used by different stations covering the adjacent service areas.However,it demands a very low carrier-tonoise ratio(C/N)threshold below 0 dB at the DTTB physical layer.In this paper,a robust broadcasting technique is proposed based on DTMB-A with newly designed low-rate low density parity check(LDPC)codes.By adopting quasi-cyclic(QC)Raptor-like structure and progressive lifting method,the high performance low-rate LDPC codes are designed supporting multiple code lengths.Both density-evolution analyses and laboratory measurements demonstrate that DTMB-A with low-rate coding can complete the demodulation reliably with the C/N threshold below0 d B,which is one important necessary condition to support frequency reuse-1 scheme.展开更多
Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small...Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small(LSS)target detection,a novel frequency domain block joint equalization algorithm is presented in this article.From the DTMB signal frame structure and channel multipath transmission characteristics,this article adopts a unconventional approach where the delay and frame structure of each DTMB signal frame are reconfigured to create a circular convolution block,facilitating concurrent fast Fourier transform(FFT)calculations.Following equalization,an inverse fast Fourier transform(IFFT)-based joint output and subsequent data reordering are executed to finalize the equalization process for the DTMB signal.Simulation and measured data confirm that this algorithm outperforms conventional techniques by reducing signal errors rate and enhancing real-time processing.In passive radar LSS detection,it effectively suppresses multipath and noise through frequency domain equalization,reducing false alarms and improving the capabilities of weak target detection.展开更多
随着地面数字电视(Digital Television Terrestrial Multimedia Broadcasting,DTMB)技术在广播电视领域的应用范围不断扩大,如何准确评估DTMB异构分配网络的覆盖效果并精准定位用户端广播电视节目信号的接收质量,是一个值得深入研究的...随着地面数字电视(Digital Television Terrestrial Multimedia Broadcasting,DTMB)技术在广播电视领域的应用范围不断扩大,如何准确评估DTMB异构分配网络的覆盖效果并精准定位用户端广播电视节目信号的接收质量,是一个值得深入研究的问题。通过分析影响DTMB网络覆盖效果评估的因素,提出一种基于位置精准性识别算法的DTMB网络覆盖效果评估方案,即利用多源位置信息匹配用户轨迹的同时,精准识别地理位置数据。经过对比验证,该方案大幅提升了DTMB网络覆盖效果评估的精确度。展开更多
仿真分析了由于高功率放大器(High Power Amplifier,HPA)的非线性失真对OFDM信号造成的影响,设计了基于清华大学DMB-T高清晰度数字电视标准的SSPA(Solid State Power Amplifier)3W功放,利用了多项式拟合及FPGA技术,考虑到曲线拟合误差和...仿真分析了由于高功率放大器(High Power Amplifier,HPA)的非线性失真对OFDM信号造成的影响,设计了基于清华大学DMB-T高清晰度数字电视标准的SSPA(Solid State Power Amplifier)3W功放,利用了多项式拟合及FPGA技术,考虑到曲线拟合误差和HPA的特性,采用了分段拟合,硬件实现了SSPA的预失真,可将带外功率失真降低约10dB左右,在很大程度上抑制了带外及带内失真。展开更多
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant 61931015the Peng Cheng Laboratory under Grant PCL2021A10+1 种基金the Science,Technology and Innovation Commission of Shenzhen Municipality(No.JSGG20201103095805015)sponsored by Tsinghua University-Yunnan Mobile Digital TV Company Ltd.,Joint Research Center(JCICBN)。
文摘As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliability by adopting flexible frame structure and advanced forward error correction coding compared with the 1 st generation DTTB systems.In order to increase the flexibility and robustness of the DTTB network,the frequency reuse scheme of factor one(reuse-1)is proposed,where the same RF channel is used by different stations covering the adjacent service areas.However,it demands a very low carrier-tonoise ratio(C/N)threshold below 0 dB at the DTTB physical layer.In this paper,a robust broadcasting technique is proposed based on DTMB-A with newly designed low-rate low density parity check(LDPC)codes.By adopting quasi-cyclic(QC)Raptor-like structure and progressive lifting method,the high performance low-rate LDPC codes are designed supporting multiple code lengths.Both density-evolution analyses and laboratory measurements demonstrate that DTMB-A with low-rate coding can complete the demodulation reliably with the C/N threshold below0 d B,which is one important necessary condition to support frequency reuse-1 scheme.
文摘Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small(LSS)target detection,a novel frequency domain block joint equalization algorithm is presented in this article.From the DTMB signal frame structure and channel multipath transmission characteristics,this article adopts a unconventional approach where the delay and frame structure of each DTMB signal frame are reconfigured to create a circular convolution block,facilitating concurrent fast Fourier transform(FFT)calculations.Following equalization,an inverse fast Fourier transform(IFFT)-based joint output and subsequent data reordering are executed to finalize the equalization process for the DTMB signal.Simulation and measured data confirm that this algorithm outperforms conventional techniques by reducing signal errors rate and enhancing real-time processing.In passive radar LSS detection,it effectively suppresses multipath and noise through frequency domain equalization,reducing false alarms and improving the capabilities of weak target detection.
文摘随着地面数字电视(Digital Television Terrestrial Multimedia Broadcasting,DTMB)技术在广播电视领域的应用范围不断扩大,如何准确评估DTMB异构分配网络的覆盖效果并精准定位用户端广播电视节目信号的接收质量,是一个值得深入研究的问题。通过分析影响DTMB网络覆盖效果评估的因素,提出一种基于位置精准性识别算法的DTMB网络覆盖效果评估方案,即利用多源位置信息匹配用户轨迹的同时,精准识别地理位置数据。经过对比验证,该方案大幅提升了DTMB网络覆盖效果评估的精确度。
文摘仿真分析了由于高功率放大器(High Power Amplifier,HPA)的非线性失真对OFDM信号造成的影响,设计了基于清华大学DMB-T高清晰度数字电视标准的SSPA(Solid State Power Amplifier)3W功放,利用了多项式拟合及FPGA技术,考虑到曲线拟合误差和HPA的特性,采用了分段拟合,硬件实现了SSPA的预失真,可将带外功率失真降低约10dB左右,在很大程度上抑制了带外及带内失真。
