Asynchronous Coded Caching With Uncoded Prefetching
Asynchronous Coded Caching With Uncoded Prefetching
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DOI：
10.1109/tnet.2020.3003907
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
H. Ghasemi;A. Ramamoorthy
中科院分区：
文献类型：
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作者：
H. Ghasemi;A. Ramamoorthy
编码的缓存是一种有望大大减少内容交付网络中网络流量的技术。但是，原始公式和该区域中的几个后续贡献假定用户的文件请求已同步，即，它们同时到达服务器。在这项工作中，当用户的文件请求在不同时间到达时，我们将制定和研究编码的缓存问题。我们假设每个用户都有一个规定的截止日期，他们希望他们的请求完成。在离线情况下，我们假设服务器在开始传输之前知道到达时间，在在线情况下，随着时间的推移，用户请求向服务器揭示。我们为离线情况提供了线性编程公式，该公式将每个用户符合其截止日期的限制的总体传输速率最小化。虽然在线案例要困难得多，但我们为此引入了一种新颖的启发式措施，并表明在某些条件下，有了很高的可能性，每个用户的要求都可以满足其截止日期的要求。我们的仿真结果表明，在存在轻度异步的情况下，仍然可以利用编码缓存的大部分好处。
Coded caching is a technique that promises huge reductions in network traffic in content-delivery networks. However, the original formulation and several subsequent contributions in the area, assume that the file requests from the users are synchronized, i.e., they arrive at the server at the same time. In this work, we formulate and study the coded caching problem when the file requests from the users arrive at different times. We assume that each user also has a prescribed deadline by which they want their request to be completed. In the offline case, we assume that the server knows the arrival times before starting transmission and in the online case, the user requests are revealed to the server over time. We present a linear programming formulation for the offline case that minimizes the overall transmission rate from the server subject to the constraint that each user meets his/her deadline. While the online case is much harder, we introduce a novel heuristic for it and show that under certain conditions, with high probability the request of each user can be satisfied with her/his deadline. Our simulation results indicate that in the presence of mild asynchronism, much of the benefit of coded caching can still be leveraged.