Cache-Aided Interference Management Using Hypercube Combinatorial Design With Reduced Subpacketizations and Order Optimal Sum-Degrees of Freedom
Xiang Zhang, Nicholas Woolsey, Mingyue Ji · IEEE Transactions on Wireless Communications · 2021
We consider a cache-aided interference network which consists of a library of N files, KTtransmitters and KRreceivers (users), each equipped with a local cache of size MTand MRfiles respectively, and connected via a discrete-time additive white Gaussian noise (AWGN) channel. Each receiver requests an arbitrary file from the library. The objective is to design a cache placement without knowing the receivers' requests and a communication scheme such that the sum Degrees of Freedom (sum-DoF) of the delivery is maximized. This network model with one-shot transmission was firstly investigated by Naderializadeh et al., who proposed a scheme achieving an order-optimal one-shot sum-DoF of min {MTKT+KRMR/N, KR}. One of the biggest limitations of this scheme is the requirement of high subpacketizations. This paper attempts to design new algorithms to reduce the file subpacketization in such a network without hurting the sum-DoF. In particular, we propose a new approach for both prefetching and linearly coded delivery based on a combinatorial design called hypercube. The proposed approach reduces the subpacketization exponentially in terms of KRM/N ( M=MTor MRrepresents the transmitter/receiver cache size) and achieves the identical one-shot sum DoF when MTKT+KRMR/N ≤ KR.