宽带卫星通信信号的多维星座图解调方法

高速卫星数据传输需要利用较高调制维度和较多星座点数来实现，一方面导致接收端具有较大实现复杂度，另一方面系统可靠性极易受信道非线性影响。针对以上问题，通过对多维星座图信号的解调性能进行理论分析，得到极大后验概率（MAP）解调误符号率（SER）的理论公式，在保证系统SER性能的基础上，提出了基于星座图相关的检测方法。该方法利用脉冲正交性得到接收星座点，对其进行向量相关运算得到解调数据，有效降低了解调判决过程的复杂度。针对信号经过高功率放大器（HPA）后的非线性失真问题，建立了HPA信道估计模型，利用最小二乘（LS）信道估计方法对原解调星座图进行修正，提出了基于修正星座图的解调方法。仿真结果表明，该方法在降低实现复杂度的同时，有效提高了系统抗HPA信道非线性失真的能力，可实现对宽带高速卫星通信信号的高效准确解调。

A Multidimensional Constellation Demodulation Method for Broadband Satellite Communication Signals

High modulation dimension and many constellation points are needed by high rate satellite communication, which increases realization complexity of the receiver and reduces system reliability in the nonlinear channel. Aimed at the above problems, the demodulation performance of multi-dimensional constellation signals is theoretically analyzed, and the symbol error ratio (SER) expression of maximum a posteriori probability (MAP) demodulation is derived. A novel constellation correlation modulation is proposed while maintaining the SER performance. In this method, the receiver obtains constellation point by orthogonally of pulse set and each constellation point is correlated as a vector with template vectors to get the demodulated data, which effectively reduces the demodulation complexity. In order to overcome nonlinearity distortion of modulated signals after high power amplifier (HPA), a multi-dimensional revised constellation demodulation method is proposed. HPA channel is estimated by least squares (LS) method and demodulation constellation is revised on the basis of estimated HPA channel. Simulation results show that the proposed demodulation method performs better in HPA channel than traditional MAP demodulation and reduces realization complexity, which is suitable for broadband satellite communication.