A new structure of next generation integrated communication system was proposed, which is composed of space segment based on satellites and terrestrial segment. Moreover, the characteristics of enhanced multiple acces...A new structure of next generation integrated communication system was proposed, which is composed of space segment based on satellites and terrestrial segment. Moreover, the characteristics of enhanced multiple access schemes based on orthogonal frequency division multiplexing (OFDM) technique were analyzed for satellite links. However, OFDM is a doubtful candidate as its higher peak-to-average power ratio (PAPR) that causes the distortion of high power amplifier (HPA). Furthermore, different schemes were evaluated and compared in terms of the HPA nonlinearity and the link level performance in detail. And the pilot-aided channel estimation and equalization techniques were also considered for analyzing the problem. Simulation results show that the bit error rate (BER) and block error rate (BLER) performance of orthogonal frequency division multiple access (OFDMA) outperforms that of single carrier-frequency division multiple access (SC-FDMA) for the satellite links in the proposed structure, though discrete Fourier transform-spread OFDM DFT-S OFDM has low PAPR, especially the BER performance of OFDMA is 3.6 dB larger than that of SC-FDMA at the target BER.展开更多
为了确保卫星系统电磁兼容性满足要求,设计了一款应用于卫星测控通信系统的小型化S频段高谐波抑制功率放大器。通过在功放输出端设置谐波抑制网络改善了电路的谐波抑制性能。采用集总与分布参数元件相结合匹配形式,实现了电路的小型化...为了确保卫星系统电磁兼容性满足要求,设计了一款应用于卫星测控通信系统的小型化S频段高谐波抑制功率放大器。通过在功放输出端设置谐波抑制网络改善了电路的谐波抑制性能。采用集总与分布参数元件相结合匹配形式,实现了电路的小型化设计。电路尺寸38. 5 mm×28. 2 mm。通过对功放腔体结构进行细化建模仿真,确保了功放电路的稳定性。实测结果表明,当工作频率为2. 52 GHz时,功放1 d B压缩点大于31 d Bm,谐波抑制度大于61 d Bc,功率附加效率高于35%, 1 d B带宽大于320 MHz。与国内外同类产品相比,该功放在谐波抑制性能等方面具有明显优势。展开更多
在跟踪和数据中继卫星系统反向链路中,多路频分复用信号通过高功率放大器时存在严重的交调干扰,导致输出的各路阵元信号严重失真.针对这一问题,该文通过幂级数模型分析高功率放大器调幅-调幅(AM-AM)变换对通道间幅度一致性的影响机理,...在跟踪和数据中继卫星系统反向链路中,多路频分复用信号通过高功率放大器时存在严重的交调干扰,导致输出的各路阵元信号严重失真.针对这一问题,该文通过幂级数模型分析高功率放大器调幅-调幅(AM-AM)变换对通道间幅度一致性的影响机理,建立幅度不一致性对波达方向(direction of arrival,DOA)估计影响的数学模型,并进行计算机仿真.理论分析和仿真结果表明:高功率放大器的AM-AM变换不会引起估计角度的偏移,但会导致空间角度范围内的谱峰值降低,同时使3 dB谱宽变宽.此外,AM-AM变换还会导致DOA估计性能恶化.展开更多
基金Project(60532030) supported by the National Natural Science Foundation of China
文摘A new structure of next generation integrated communication system was proposed, which is composed of space segment based on satellites and terrestrial segment. Moreover, the characteristics of enhanced multiple access schemes based on orthogonal frequency division multiplexing (OFDM) technique were analyzed for satellite links. However, OFDM is a doubtful candidate as its higher peak-to-average power ratio (PAPR) that causes the distortion of high power amplifier (HPA). Furthermore, different schemes were evaluated and compared in terms of the HPA nonlinearity and the link level performance in detail. And the pilot-aided channel estimation and equalization techniques were also considered for analyzing the problem. Simulation results show that the bit error rate (BER) and block error rate (BLER) performance of orthogonal frequency division multiple access (OFDMA) outperforms that of single carrier-frequency division multiple access (SC-FDMA) for the satellite links in the proposed structure, though discrete Fourier transform-spread OFDM DFT-S OFDM has low PAPR, especially the BER performance of OFDMA is 3.6 dB larger than that of SC-FDMA at the target BER.
文摘为了确保卫星系统电磁兼容性满足要求,设计了一款应用于卫星测控通信系统的小型化S频段高谐波抑制功率放大器。通过在功放输出端设置谐波抑制网络改善了电路的谐波抑制性能。采用集总与分布参数元件相结合匹配形式,实现了电路的小型化设计。电路尺寸38. 5 mm×28. 2 mm。通过对功放腔体结构进行细化建模仿真,确保了功放电路的稳定性。实测结果表明,当工作频率为2. 52 GHz时,功放1 d B压缩点大于31 d Bm,谐波抑制度大于61 d Bc,功率附加效率高于35%, 1 d B带宽大于320 MHz。与国内外同类产品相比,该功放在谐波抑制性能等方面具有明显优势。
文摘在跟踪和数据中继卫星系统反向链路中,多路频分复用信号通过高功率放大器时存在严重的交调干扰,导致输出的各路阵元信号严重失真.针对这一问题,该文通过幂级数模型分析高功率放大器调幅-调幅(AM-AM)变换对通道间幅度一致性的影响机理,建立幅度不一致性对波达方向(direction of arrival,DOA)估计影响的数学模型,并进行计算机仿真.理论分析和仿真结果表明:高功率放大器的AM-AM变换不会引起估计角度的偏移,但会导致空间角度范围内的谱峰值降低,同时使3 dB谱宽变宽.此外,AM-AM变换还会导致DOA估计性能恶化.
