數位噴泉技術實現不等差錯保護的優化設計

Abstract

隨著多媒體廣播應用的越來越廣泛，對於資訊分層的需求也越來越突出。本文首先針對資訊分層後不同優先順序的層間如何進行不等差錯保護(UEP)的問題，提出了一種與噴泉碼自身的編解碼過程完全解耦的UEP調度方案：機會噴泉，然後分別建立了系統開銷一定下使用者滿意度最大和使用者滿意度一定下系統開銷最小的優化模型。通過優化概率分佈來控制不同層的資料包開銷量，以此達到不同資訊層的不等差錯保護。模擬結果表明：機會噴泉的方案在最優設計下，用戶滿意度較之相等差錯保護的方案有10%~15%的提升。With the explosive growth of multimedia broadcasting applications in recent years, the demand for layered streaming has increased significantly. In order to meet the quality of service requirements, unequal error protection technique has been considered. In this paper, we propose an opportunistic fountain scheme for layered streaming using rateless codes. The proposed scheme provides unequal error protection property by scheduling strategy, decoupled from rateless code structure. To find the optimal scheduling strategy two optimization models are developed, which maximizes the user satisfaction degree subject to overhead and minimizes the overhead subject to some fixed user satisfaction degree respectively. Simulation results show that with the optimal design of the opportunistic fountain scheme, user satisfaction degree is improved by 10%~15% compared to EEP scheme.