Improved Coded Caching Scheme for Multi-User Information Retrieval System

TL;DR

This paper introduces an improved coded caching scheme for multi-user information retrieval systems that reduces communication latency, computational complexity, and subpacketization, especially when certain system parameters satisfy a specific condition.

Contribution

The paper adapts the MAPDA approach for MIR systems, simplifying precoding and achieving lower complexity and subpacketization without increasing NDT.

Findings

Achieves lower computational complexity compared to existing schemes.

Reduces subpacketization levels while maintaining the same NDT.

Provides both theoretical and numerical validation of improvements.

Abstract

In this paper, we study the coded caching scheme for the $(L, K, M, N)$ multi-user information retrieval (MIR) system, which consists of a content library containing $N$ files, a base station (BS) with $L$ antennas that cannot access the library, and $K$ single-antenna users, each of which can cache at most $M$ files from the library. The users communicate with the others assisted by the BS to decode their required files. In this paper, we focus on designing a coded caching scheme with low communication latency measured by normalized delivery time (NDT), computational complexity, and subpacketizations. When $\frac{KM}{N}\geq L$ we first simply the precoding matrix in the downlink step to an identity matrix and use the multiple-antenna placement delivery array (MAPDA), which was originally proposed for the multiple-input single-output networks, to generate several new schemes for MIR system. Compared to the existing schemes, both the theoretical and numerical analyses show that our new schemes achieve much lower computational complexity and smaller subpacketizations with the same NDT.