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LDPC码在QPSK调制下的应用分析 被引量:1
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作者 陈正康 马林华 +1 位作者 苏强 彭鑫 《电光与控制》 北大核心 2010年第4期90-92,共3页
对低密度奇偶校验码(LDPC)在QPSK调制下的对数似然比(LLR)算法进行了深入研究,分析了LDPC码在QPSK调制下初始消息的计算方法,推导了初始消息的计算公式。同时对该算法进行了程序仿真,仿真结果表明LDPC码在QPSK调制中具有良好的性能。当... 对低密度奇偶校验码(LDPC)在QPSK调制下的对数似然比(LLR)算法进行了深入研究,分析了LDPC码在QPSK调制下初始消息的计算方法,推导了初始消息的计算公式。同时对该算法进行了程序仿真,仿真结果表明LDPC码在QPSK调制中具有良好的性能。当信噪比为3.5 dB时,误码率可达到10-6数量级。 展开更多
关键词 低密度奇偶校验码(LDPC) qpsk 调制
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信道预测和天线选择的空时码DE-QPSK误码性能分析 被引量:2
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作者 汪玲波 李光球 钱辉 《通信技术》 2018年第8期1791-1796,共6页
克服因反馈时延引起的无线通信系统误码性能恶化问题的一种有效手段,是采用最小均方误差(MMSE)维纳滤波信道预测器,并推导了瑞利块衰落信道上采用信道预测发射天线选择(TASP)/正交空时分组码(OSTBC)的相干检测差分编码四相相移键控(DE-Q... 克服因反馈时延引起的无线通信系统误码性能恶化问题的一种有效手段,是采用最小均方误差(MMSE)维纳滤波信道预测器,并推导了瑞利块衰落信道上采用信道预测发射天线选择(TASP)/正交空时分组码(OSTBC)的相干检测差分编码四相相移键控(DE-QPSK)的平均误符号率(ASER)精确和近似解析表达式。仿真结果验证了上述理论分析的正确性和近似计算的准确性,DE-QPSK的ASER解析表达式可以用于快速评估收发天线数、信道预测器长度等参数对TASP/OSTBC无线通信系统ASER性能的影响,为TASP/OSTBC系统设计提供指导。 展开更多
关键词 信道预测 发射天线选择 正交空时分组码 差分编码四相相移键控 平均误符号率
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Cooperative DVB-SH Satellite Broadcasting Systems with Rotated Signal Constellations
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作者 Nikos C.Sagias Stylianos Papaharalabos P.Takis Mathiopoulos 《China Communications》 SCIE CSCD 2015年第6期59-72,共14页
In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) wi... In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates. 展开更多
关键词 BROADCASTING code combining constellation rotation coding rate comple-mentary ground system (CGS) coopera-tion digital video broadcasting satellite-to-hand-held (DVB-SH) DECODE-AND-FORWARD log-likelihood ratio (LLR) quadrature phase-shift keying (qpsk orthogonal frequency-di-vision multiplexing (OFDM) relays satellitecommunications soft-decision decoding tur-bo codes random interleavers
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