【摘要】 考虑了一个结合自适应调制和自动重传请求的蜂窝下行系统,基站通过接收端的反馈获得其信道信息,然后在物理层通过自适应地选择调制和编码方式来最大化系统频谱效率,同时还在数据链路层采用自动重传技术来提高传输的鲁棒性.研究了在业务的平均延时约束下,通过最优选取自适应调制参数来最大化系统的频谱效率的方法.首先通过合理的假设对上述系统数学建模,然后将研究的问题建模为一个凸优化问题,并最终通过经典的拉格朗日乘数法给出了最优解.数值仿真表明本算法是最优的.更多还原

【Abstract】 A cellular downlink system combining AMC and ARQ is considered.The BS obtains the channel state information through the feedback of the receiver,and then adaptively chooses the modulation and coding method at the physical layer to maximize the system spectrum efficiency.At the same time,ARQ at the data link layer is also adopted to improve the robustness performance.Based on this cross-layer system,the problem of spectral efficiency maximization for non-realtime services is studied,that is,how to maximize the spectral efficiency by optimally choosing the AMC parameters under the average delay constraint.First,the above cross-layer system is modeled under some reasonable assumptions.Then,the studied problem is formulated as a convex optimization one.Finally,this problem is solved with the classical Lagrangian method.Numerical simulations show that our proposed method is optimal.更多还原