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无线信道中的单载波频域均衡技术 总被引:2,自引:0,他引:2
本文介绍了时域均衡的单载波系统、多载波正交频分复用系统和频域均衡的单载波系统。频域均衡单载波系统复杂度和性能与多载波系统相当,可以与多载波系统共存,已被IEEE 802.16建议在宽带无线接入中采用。 相似文献
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介绍了单载波频域均衡(SC-FDE)的原理和均衡实现的过程,并采用时域 LS 信道估计算法对频域均衡性能进行了仿真。 相似文献
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介绍了单载波频域均衡技术的原理,与单载波时域均衡以及多载波OFDM系统进行了比较。该技术结合了两者的优点:能有效对抗多径信道,且具有较低的复杂度;降低了峰均比和对载波频偏、相位噪声的敏感性,因而在无线通信领域具有广阔的应用前景。 相似文献
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单载波频域均衡抗多径码元同步跟踪方法 总被引:1,自引:1,他引:0
从信道估计时域冲激响应能量出发,提出了一种运行在2倍采样率上的基于数据分组累积能量的抗多径码元定时同步跟踪方法,适合在全响应和部分响应升余弦脉冲成形QPSK调制的单载波频域均衡系统中应用。在多径信道下对该码元定时同步跟踪方法的跟踪性能进行了仿真,仿真结果表明,该码元定时同步跟踪方法具有良好的跟踪性能和抗多径、抗噪声能力。 相似文献
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未来无线通信中的单载波频域均衡技术 总被引:9,自引:0,他引:9
本文介绍了单载波频域均衡技术的原理,这种技术能有效对抗频率选择性衰落,并且具有较低的复杂度,同时避免了OFDM的高峰均比问题,在对载波频偏和相位噪声的敏感度上也优于OFDM系统,因而在未来高速无线通信中具有广阔的应用前景。 相似文献
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单载波频域均衡在地空高速数据链的应用 总被引:1,自引:0,他引:1
地空数据链的信道属于低仰角的多径信道,存在较严重的符号间干扰。正交频分复用(OFDM)是得到认可的有效抗多径方案,单载波频域均衡(SC-FDE)采用与OFDM相似的频域均衡方式,具有与OFDM相近的性能和复杂度,并克服了OFDM的一些不足。在比较SC-FDE和OFDM相似性、分析SC-FDE的信道估计与均衡基础上,提出了采用SC-FDE的地空高速数据链解调器结构,该结构在保留单载波处理的优点条件下实现高效的频域均衡。 相似文献
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全面分析了中国国情下地面数字电视传输系统的需求状况,并根据这些需求设计了性能更优的TiMi地面数字电视传输系统方案。 相似文献
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Emad S. Hassan Xu Zhu Said E. El‐Khamy Moawad I. Dessouky Sami A. El‐Dolil Fathi E. Abd El‐Samie 《International Journal of Communication Systems》2011,24(1):1-13
In this paper, we study the performance of the continuous phase modulation (CPM)‐based orthogonal frequency division multiplexing (CPM‐OFDM) system. Also, we propose a CPM‐based single‐carrier frequency domain equalization (CPM‐SC‐FDE) structure for broadband wireless communication systems. The proposed structure combines the advantages of the low complexity of SC‐FDE, in addition to exploiting the channel frequency diversity and the power efficiency of CPM. Both the CPM‐OFDM system and the proposed system are implemented with FDE to avoid the complexity of the equalization. Two types of frequency domain equalizers are considered and compared for performance evaluation of both systems; the zero forcing (ZF) equalizer and the minimum mean square error (MMSE) equalizer. Simulation experiments are performed for a variety of multipath fading channels. Simulation results show that the performance of the CPM‐based systems with multipath fading is better than their performance with single path fading. The performance over a multipath channel is at least 5 and 12 dB better than the performance over a single path channel, for the CPM‐OFDM system and the proposed CPM‐SC‐FDE system, respectively. The results also show that, when CPM is utilized in SC‐FDE systems, they can outperform CPM‐OFDM systems by about 5 dB. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Fast frequency hopping/orthogonal frequency division multiplexing (FFH/OFDM) has been previously proposed to achieve frequency diversity over frequency selective channels. However, the performances of the FFH/OFDM scheme have been usually calculated using simulations over empirical channel models in earlier works. The main aim of this paper is to theoretically expose the diversity of the FFH/OFDM signal over statistical models, specifically Rayleigh distributed, for frequency selective fading channels. In order to achieve this aim, we first derive the decision variables and the signal‐to‐interference noise ratios of the FFH/OFDM signal at the output of minimum mean square error and zero forcing receivers. For various levels of quadrature amplitude modulation used in FFH/OFDM, the performances are calculated and validated via simulations. The results show that FFH/OFDM in case of zero forcing equalization does not provide any diversity gain even over a frequency selective channel. However, in case of minimum mean square error equalization, it brings significant diversity gain at high signal‐to‐noise ratio (SNR) values with the rise of number of sub‐carriers. Moreover, the FFH/OFDM with four quadrature amplitude modulation scheme provides better performance than that of the conventional OFDM even at low SNR values, as well as a significant diversity gain at high SNR values. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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频域均衡的单载波传输方案研究 总被引:1,自引:0,他引:1
无线信道的信道干扰主要表现为多径衰落和多普勒衰落对信道的影响。我们可以采用均衡技术来补偿信道中由于多径效应产生的码间干扰(ISI)。现引入频域均衡的单栽波传输(SC/FDE)方案,探讨了其实现机理,并对采用SC/FDE的高速率无线通讯系统实例进行系统整体建模和仿真计算。 相似文献
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无人机地空链路信道特性与宽带数据传输 总被引:1,自引:0,他引:1
无人机地空链路数据传输存在多径衰落的影响。详细分析了无人机在滑行、起降和巡航3种状态下地空信道的传输特性。针对滑行、起降阶段多径时延大、存在频率选择性衰落的问题,提出了宽带数据传输技术——单载波频域均衡(SC-FDE)和正交频分复用(OFDM),并对SC-FDE进行了性能仿真。仿真结果表明,SC-FDE可以有效解决无人机滑行、起降阶段的多径衰落影响,提高宽带数据传输质量。 相似文献
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单载波频域均衡技术由于其能有效的对抗频率选择性衰落,成为被多种新兴高速率通信系统所推荐的关键技术之一.利用Matlab/Simulink组件,对单载波频域均衡系统进行了仿真实现.结果显示,单载波频域均衡系统的误码率保持在10-3的数量级上. 相似文献
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《Optical Fiber Technology》2014,20(5):453-460
Optical superchannel employing single-carrier (SC) and multi-carrier (MC) subband modulation techniques have been widely discussed for high-speed coherent optical transmission and networks. In this paper, we establish uniform system design based on frequency-domain equalization (FDE) and carry out a thorough study on orthogonal frequency division multiplexing (OFDM) superchannel versus SC frequency division multiplexing (SCFDM, also named as DFT-spread-OFDM) superchannel. The baseband signal characteristics of SCFDM and OFDM are analyzed. SCFDM and OFDM superchannel systems with 4-, 16-, 64- and 256-QAM formats and polarization division multiplexing (PDM) are numerically investigated against various impairments. The results show that SCFDM superchannel outperforms its MC counterpart against finite DAC&ADC resolution and fiber nonlinearities, while suffers more penalty when very large dispersion or laser phase noise exists. 相似文献
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针对单载波频域均衡系统MMSE均衡器存在残留码间干扰的缺点,提出MMSE-RISIC判决反馈均衡器消除残留码间干扰.MMSE-RISIC均衡器采用传统MMSE均衡后的判决数据,对残留码间干扰进行估计并消除.残留码间干扰的估计主要采用FFT和IFFT运算,与其他方法相比计算量较小.对该均衡器在不同信道下进行了计算机仿真,结果表明,在频率选择性衰落信道条件下,系统性能有了较为明显的提高. 相似文献