Abstract: In the near space communication network，limited wireless resources are shared by every users，thus，an effective Media Access Control（MAC） protocol should be designed.Demand Assignment Multiple Access（DAMA） protocol is applied to near space communication network，an analytical model is presented according to queue theory，to evaluate the mean end-to-end delay of packets traversing a near space link with a DAMA scheduling strategy and fixed frame length，a simulation model is also established using OPNET software.Simulation results show theoretic analysis can accurately estimate the mean end-to-end delay of the network.

Key words: near space communication network, Demand Assignment Multiple Access（DAMA）, queue theory, time delay, OPNET

摘要： 在临近空间通信网络中，各个用户要共享带宽有限的无线信道，因此，需要设计一种有效的MAC层协议。提出将按需分配（DAMA）多址接入协议应用到临近空间通信网中，运用排队理论建立了分析模型，对在固定帧长条件下该协议的平均端到端时延性能进行了理论分析，并利用OPNET仿真软件进行仿真验证。结果表明，理论分析能较准确地估计网络的平均端到端时延。

关键词: 临近空间通信网, 按需分配, 排队论, 时延, OPNET软件