| 摘要: |
| 空基网络通信应用中，采用恒包络波形体制可以降低设备特别是功放的复杂度，因此高效的成形偏移四相相移键控(SOQPSK)信号非常适合于空基网络。但是机载通信中多普勒频移较大，在低信噪比和短突发条件下，SOQPSK相干接收机必须有精确的载波频率和相位同步才能获得较好的性能。针对低信噪比和短突发场景，提出了基于Turbo乘积码（TPC）编码的扩频SOQPSK宽带网络波形，并设计了导频与数据帧结构，利用译码器输出的软信息来改善载波同步的性能，通过迭代操作和联合解调、解扩，增强了系统的同步性能。仿真结果表明，在误码率为10-6时所需Eb/N0为3.65 dB，达到了波形设计指标要求。 |
| 关键词: 空基网络通信 突发波形 SOQPSK信号 TPC编码 载波同步 软信息 |
| DOI： |
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| 基金项目: |
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| An SOQPSK burst waveform for wideband network |
| XU Lin,SUN Jinhua,LIU Yi |
| (Southwest China Institute of Electronic Technology,Chengdu 610036,China;State Key Laboratory of Integrated Service Networks,Xidian University,Xi′an 710071,China;UoG-UESTC Joint School,Chengdu 611731,China) |
| Abstract: |
| In airborne network communications,constant envelope waveform system is used to reduce equipment complexity,especially power amplifier.So efficient Shaped-Offset Quadrature Phase-Shift Keying（SOQPSK） is very suitable to airborne network.However,Doppler frequency offset is relatively large.Under low signal-to-noise ratio(SNR) and short burst conditions,accurate carrier frequency and phase synchronization are important factors affecting the performance of coherent receivers.For low SNR and short burst conditions,a wideband network waveform based on Turbo Product Code(TPC) coded spread spectrum SOQPSK waveform is proposed in this paper and the frame structure is designed.The carrier synchronization performance is improved by using the soft information value of the output of the Turbo decoder.Through iterative operation and combination of demodulation and dispreading,the synchronization performance is enhanced.Simulation results show that the required Eb/N0 is 3.65 dB at bit error rate(BER) of 10-6,which meets the design requirements. |
| Key words: airborne network communication burst waveform SOQPSK signal TPC coding carrier synchronization soft information |
