多信道无线多跳网络中视频流的跨层优化

为提高视频流在多信道无线多跳网络中的传输质量,提出了一种分布式的跨层优化算法.首先对信道分配、干扰、带宽分配、延时分配和视频传输失真进行了数学建模,然后基于凸规划和拉格朗日对偶分解理论,在视频流端到端延时限制下通过调整信源编码速率、链路带宽、链路平均延时上限及射频和信道分配来最小化总的视频流失真.理论分析和数值仿真表明,所提出的分布式跨层优化算法可以收敛到全局最优解.

Cross-Layer Optimization of Video Stream in Multi-Channel Wireless Multihop Networks

This paper formulated channel allocation, interference, bandwidth allocation, delay allocation and video stream distrotion in multi-radio and multi-channel wireless multi-hop networks, the optimization aims to minimize the total distortion of video streams. We decomposed the optimization problem into two subproblems: channel allocation and joint resource encoding, bandwidth and delay allocation. We analysised the convex character for the latter problem, and use Lagrange dual theory to decompose it into three distributed subproblems: resource encoding, bandwidth allocation and delay allocation. We proposed both centralized and distributed cross-layer optimization algorithms. The distributed one contain two sections: distributed resource encoding, bandwidth allocation and delay allocation algorithm, and minimal interference cost based channel allocation algorithm. Simulation results show that: the video streams rate increases and the distrotion falls with the number of radios and channels increases; the delay restriction has little influence on video streams rate and distrotion; the proposed algorithms can convergence to the overall optimal solutions.