非均匀信道增益控制的多载波卫星容量分析

Capacity Analysis of Multi-Carrier SATCOM Systems with Heterogeneous Gain-State Control

设置转发器最佳增益,减小功放非线性影响,提高系统容量是多载波卫星通信系统容量分析的首要问题。对于数字信道化转发器,采用非均匀子信道增益调整的思想独立设置各信道增益可以有效消除大小载波抑制问题,提高卫星系统容量。为此,提出一种直接计算求解各子信道增益的算法。该方法不需要采用复杂的优化过程以及矩阵求逆,因此适合求解任意数量链路增益。理论推导得到链路最佳发射功率为地面站最大可提供功率,通过直接计算非线性等式即可获得各子信道最佳增益。同时考虑到功率利用率问题,通过选取转发器最佳工作点,在最小转发器输出功率准则下可以有效提高卫星功率的利用率。实验结果表明,该算法在具有与优化算法相近性能的同时降低了求解复杂度。

To set the transponder＇ s optimal gain, reduce the HPA＇s nonlinear influence and increase the capacity of the muhi-carrier SATCOM systems are the first problems in satellite capacity analysis. With the concept of applying gain to individual links for digital channelized transponder, it could reduce the problem of suppression from stronger signals to the weaker effectively. Therefore, a directly salving algorithm is proposed for calculating the optimal gain of each sub-channel. The new method does not utilize any search algorithms or matrix inversion thus it can be used for any number of links in a transponder. As seen from theoretical analysis that the optimal terminals transmit powers are the allowable EIRP and the optimal gains for individual links could be directly solved by using of a set of simple nonlinear equations. Meantime, considering the transponder＇ s power utility, the new algorithm can improve the power utilization through searching the optimum transponder＇ s operating point under the criterion of minimizing the output power from the satellite transponder. The experimental results show that the proposed algorithm has similar performance to some optimization algorithm, while reduces the computational complexity.