一种基于跨层反馈信息的下行OFDMA资源分配策略

摘要

基于跨层调度的思想,本文深入研究了正交频分多址(OFDMA)系统中的资源分配问题.本文提出的调度算法联合利用了媒体访问控制(MAC)层的确认字符(ACK/NAK)信息和物理层(PHY)周期反馈的用户信噪比(SNR)信息.同时该调度问题在本文中被建模成一个带有跨层观测信息的部分观测马尔科夫决策过程(POMDP).为了降低复杂度,本文利用了一个简化的模型,使其能够应用于实际的系统中.数学仿真显示,本文提出算法的性能十分接近Aggarwal R等人提出的理论上限,并且通过利用ACK/NAK信息大大减小了系统的反馈开销.%The problem of the cross-layer scheduling and resource allocation in orthogonal frequency division multiplexing access (OFDMA) downlink was considered, utilizing the ACK/NAK in MAC layer and periodic feedback of users' SNR in physical layer simultaneously. This problem was modeled as a partially observable Markov decision process (POMDP) with cross-layer observations, and a simplified version was proposed to reduce the computational complexity. Numerical experiments show that the performance of the algorithm is relatively close to the upper bound proposed by Aggarwal R, and does not increase the system overhead of feedback.