Abstract: For LEO satellite networks, it is impossible to estimate the real-time traffic load in mobile spot-beam, a new mechanism is proposed to optimize dynamic guard channel scheme based on the current traffic changing states during system simulation procedure. This strategy uses a call interval time and handover call dropping interval time to learn about real-time states of system traffic and estimate the call dropping probability based on real-time traffic load by simulation. Compared the calculated call dropping probability with the predefined QoS（Quality of Service）, the number of guard channels is changed dynamically. Simulation results show that the proposed mechanism can improve the system stability efficiently. When traffic load is not heavy, ODGCS can guarantee the QoS of handoff call and decrease the new call blocking probability compared with the traditional guard channel scheme.

摘要： 由于LEO（Low Earth Orbit）卫星网络中不断变化的点波束小区实时通信量负载无法估计，提出了一种根据系统仿真过程中当前通信量状态优化动态保护信道算法（ODGCS）。该分配策略引入呼叫间隔时间和切换呼叫中断间隔时间来获悉系统的实时性能状态，由仿真中通信量状态预测当前系统切换呼叫的中断概率，根据比较计算的呼叫中断概率和预先设定的QoS（Quality of Service）值，动态调整预留给切换呼叫使用的保护信道数。仿真结果表明，与传统的静态预留保护信道的算法相比，该算法能有效提高LEO卫星系统的性能稳定性。在负载较轻时，ODGCS算法保证切换呼叫QoS的同时，降低了新呼叫阻塞概率。