Reliable Coded Caching Design Over Wireless Networks

Abstract

In this paper, we will show how to interpret the coded caching design from error control coding perspective. It is shown that, when the cached and non-cached contents in the placement phase is thought of as the shortened system packets and the punctured system packets, respectively, while those coded contents transmitted in the delivery phase specify the parity packets, the coded caching design can be reformulated as a collaborative error control coding problem. The challenges for arbitrary user requests and noncooperative decoding nature at every user will be highlighted to address the design criteria in order to exploit the coding gain residing in the coded caching. Our analysis unveils that, with some <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">supplementary parity packets</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SPPs</i> ) included in either the placement phase or the delivery phase, noticeable transmission reliability improvement can be realized. It is shown that the proposed design is able to flexibly fulfill the asymmetric reliable transmission requirement by placing or transmitting some <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SPPs</i> only for those users in adverse conditions. It is also shown that the proposed reliable coded caching and channel coding can be further integrated into the joint network-channel coding (JNCC) framework to fully exploit the benefits of those two schemes.