基于网络效用的OFDM卫星移动通信系统呼叫接纳控制

在天地一体化网络中,OFDM卫星移动通信系统更有利于与地面无线网络融合.呼叫接纳控制是无线资源管理中的关键问题,本文针对OFDM卫星移动通信系统提出了一种基于网络效用和动态系统资源的星上呼叫接纳控制方法,采用集中式接纳控制,对卫星系统资源的集中管理可有效降低呼叫等待时延.所提出的接纳控制方法基于不同业务的网络效用函数,采用跨层设计思想,根据物理层卫星信道状态变化更新OFDM子载波传输能力,在呼叫接纳控制过程中动态调整分配业务带宽,实现整个网络效用最大化,同时保证业务的QoS要求.仿真结果表明,在系统业务负载饱和的情况下,该方法系统资源利用效率显著优于基于用户端最小阻塞概率的接纳控制方法和基于用户端业务QoS的接纳控制方法,非常适合于资源受限的卫星系统.

Network Utility Based Call Admission Control for OFDM Satellite Mobile Communication System

In space-earth integrated networks,a satellite mobile communication system based on OFDM is more conducive to integration of terrestrial wireless networks.Call admission control is a key problem in wireless resource management.An on-board call admission control scheme based on network utility and dynamic system resource is proposed for the OFDM satellite mobile communication system in this paper.Centralized admission control is adopted,and centralized satellite resource management can reduce call waiting delay effectively.The proposed call admission control scheme is based on the network utility functions of different services and cross-layer design.In physical layer the OFDM subcarrier transmission capability is updated according to the satellite channel state,and then the allocated service bandwidth is adjusted dynamically in call admission control process to realize maximization of the total network utility,in the meantime service QoS can be satisfied.Simulation results show that the proposed scheme has notable superiority in system resource utilization rate compared with admission control schemes based on both minimum blocking probability and user service QoS.It is very suitable to resource limited satellite system.