We present a novel low-complexity scheme for cache-aided communication, where a multi-antenna base station serves multiple single-antenna mobile users. The scheme is based on dividing the users into meta-users, where all users in the same meta-user store the same content during the placement phase. The inter meta-user interference is mitigated by using the cache as well as zero forcing, while the interference between users of the same meta-user is mitigated by zero forcing. Compared to the current state of the art, this scheme is feasible for a wider range of parameters. Moreover, while still achieving the optimal number of degrees of freedom (DoF), the proposed scheme imposes the same or less complexity compared to all the known schemes for each set of parameters. Consequently, the proposed scheme enables practical implementation of cache-aided communication for a large number of users.
more »
« less
Simple Caching Schemes for Non-homogeneous MISO Cache-Aided Communication via Convexity
We present a novel scheme for cache-aided communication over multiple-input
and single output (MISO) cellular networks. The presented scheme achieves the same number of degrees of freedom as known coded caching schemes, but, at much lower complexity. The scheme is derived for communication systems with heterogeneous rates and finite signal-to-noise ratio, in which links are modeled by wideband fading channels. The base station is serving multiple users simultaneously, by sending a combination of several packets, each intended for one user. The interference is either suppressed using the cache content or nulled by zero-forcing at the unintended users. We focus on efficient coding schemes, which allow for a maximum number of users to be served throughout the course of communication. An achievable rate region is characterized by determining the extreme rate vectors satisfying an efficient transmission. The analysis results in a simple scheduling scheme and in a closed-form performance analysis.
more »
« less
- Award ID(s):
- 1749981
- NSF-PAR ID:
- 10164734
- Date Published:
- Journal Name:
- ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)
- Page Range / eLocation ID:
- 4980 to 4984
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
In the problem of cache-aided Multiuser Private Information Retrieval (MuPIR), a set of K u cache-aided users wish to download their desired messages from a set of N distributed non-colluding databases each holding a library of K independent messages. The communication load of this problem is defined as the total number of bits downloaded (normalized by the message length) by the users. The goal is to find the optimal memory-load trade-off under the constraint of user demand privacy, which ensures that any individual database learns nothing about the demands of the users. In this paper, for the MuPIR problem with K=2 messages, Ku=2 users and N≥2 databases, we provide achievability for the memory-load pairs (N−12N,N+1N) and (2(N−1)2N−1,N+12N−1) by constructing specific achievable schemes based on the novel idea of Private Cache-aided Interference Alignment (PCIA). We prove that the proposed scheme is optimal if the cache placement is uncoded (i.e., users directly cache a subset of the library bits). Computer-aided investigation also shows that the proposed schemes are optimal in general when N=2,3.more » « less
-
In the problem of cache-aided Multiuser Private Information Retrieval (MuPIR), a set of Ku cache-aided users wish to download their desired messages from a set of N distributed non-colluding databases each holding a library of K independent messages. The communication load of this problem is defined as the total number of bits downloaded (normalized by the message length) by the users. The goal is to find the optimal memory-load trade-off under the constraint of user demand privacy, which ensures that any individual database learns nothing about the demands of the users. In this paper, for the MuPIR problem with K = 2 messages, K u = 2 users and N ≥ 2 databases, we provide achievability for the memory-load pairs (N-1/2N, N+1/N) and(2(N-1)/2N-1,N+1/2N-1) by constructing specific achievable schemes based on the novel idea of Private Cacheaided Interference Alignment (PCIA). We prove that the proposed scheme is optimal if the cache placement is uncoded (i.e., users directly cache a subset of the library bits). Computer-aided investigation also shows that the proposed schemes are optimal in general when N = 2, 3.more » « less
-
Coded caching is a technique for reducing congestion in communication networks by prefetching content during idle periods and exploiting multicasting opportunities during periods of heavy traffic. Most of the existing research in this area has focused on minimizing the worst case (i.e., peak) rate in a broadcast link with multiple identically distributed user requests. However, modern content delivery networks are investing very heavily in profiling their users and predicting their preferences. The minimal achievable rate of a coded caching scheme with heterogeneous user profiles is still unknown in general. This paper presents the first steps towards solving that problem by analyzing the case of two users with distinct but overlapping demand sets. Specifically, it provides a complete characterization of the uniform-average-rate capacity when the sets overlap in just one file and shows that such capacity can be achieved with selfish and uncoded prefetching. Then, it characterizes the same capacity under selfish and uncoded prefetching when the demand sets overlap in two or more files. The paper also provides explicit prefetching schemes that achieve those capacities. All our results allow for arbitrary (and not necessarily identical) users’ cache sizes and number of files in each demand set.more » « less
-
We present novel schemes for cache-aided communication over networks with a multi-antenna base station (BS) that serves multiple single-antenna users. The schemes are based on a greedy scheduling [1], which simultaneously transmits coded messages to disjoint groups of users. The proposed algorithms use the channel state information to opportunistically choose the groups to be served together and to allocate power to each coded message in order to minimize the overall communication delay. Numerical study shows that the new schemes outperform the previously known schemes.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ICASSP40776.2020.9053936
