
VIT-CAT: PARALLEL VISION TRANSFORMERS WITH CROSS ATTENTION FUSION FOR
POPULARITY PREDICTION IN MEC NETWORKS
Zohreh HajiAkhondi-Meybodi†, Arash Mohammadi‡, Ming Hou†‡,
Jamshid Abouei††, Konstantinos N. Plataniotis‡‡
†Electrical and Computer Engineering, Concordia University, Montreal, Canada
‡Concordia Institute of Information Systems Engineering (CIISE), Montreal, Canada
†‡ Defence Research and Development Canada (DRDC), Toronto, Canada
†† Department of Electrical Engineering, Yazd University, Yazd, Iran
‡‡ Electrical and Computer Engineering, University of Toronto, Toronto, Canada
ABSTRACT
Mobile Edge Caching (MEC) is a revolutionary technology for the
Sixth Generation (6G) of wireless networks with the promise to sig-
nificantly reduce users’ latency via offering storage capacities at the
edge of the network. The efficiency of the MEC network, however,
critically depends on its ability to dynamically predict/update the
storage of caching nodes with the top-Kpopular contents. Conven-
tional statistical caching schemes are not robust to the time-variant
nature of the underlying pattern of content requests, resulting in a
surge of interest in using Deep Neural Networks (DNNs) for time-
series popularity prediction in MEC networks. However, existing
DNN models within the context of MEC fail to simultaneously cap-
ture both temporal correlations of historical request patterns and the
dependencies between multiple contents. This necessitates an ur-
gent quest to develop and design a new and innovative popularity
prediction architecture to tackle this critical challenge. The paper
addresses this gap by proposing a novel hybrid caching framework
based on the attention mechanism. Referred to as the parallel Vision
Transformers with Cross Attention (ViT-CAT) Fusion, the proposed
architecture consists of two parallel ViT networks, one for collecting
temporal correlation, and the other for capturing dependencies be-
tween different contents. Followed by a Cross Attention (CA) mod-
ule as the Fusion Center (FC), the proposed ViT-CAT is capable of
learning the mutual information between temporal and spatial cor-
relations, as well, resulting in improving the classification accuracy,
and decreasing the model’s complexity about 8times. Based on the
simulation results, the proposed ViT-CAT architecture outperforms
its counterparts across the classification accuracy, complexity, and
cache-hit ratio.
Index Terms—Mobile Edge Caching, Popularity Prediction,
Deep Neural Networks, Vision Transformer, Cross-Attention.
1. INTRODUCTION
The phenomenal growth in demand for mobile wireless data ser-
vices, together with the emergence of advanced Internet of Things
(IoT) applications bring new technical challenges to wireless com-
munications. According to Ericsson’s mobility report [1], global
mobile data traffic is projected to exponentially grow from 67 ex-
abytes/month in 2021 to 282 exabytes/month in 2027. To accommo-
date the huge amount of mobile data traffic, Mobile Edge Caching
This Project was partially supported by Department of National De-
fence’s Innovation for Defence Excellence & Security (IDEaS), Canada.
(MEC) [2–5] has emerged as a promising solution for potential de-
ployment in the Sixth Generation (6G) of communication networks.
MEC networks provide low-latency communication for IoT devices
by storing multimedia contents in the storage of nearby caching
nodes [6, 7]. The limited storage of caching nodes, however, makes
it impossible to preserve all contents on nearby devices. To tackle
this challenge, predicting the most popular content is of paramount
importance, as it can significantly influence the content availability
in the storage of caching nodes and reduce users’ latency.
Existing popularity prediction solutions are typically developed
based on statistical models [6–10], Machine Learning (ML)-based
architectures [11–14], and Deep Neural Networks (DNNs) [15–24],
among which the latter is the most efficient one for popularity pre-
diction. This is mainly due to the fact that DNN-based models can
capture users’ interests from raw historical request patterns without
any feature engineering or pre-processing. In addition, DNN-based
popularity prediction models are not prone to sparsity and cold-start
problems with new mobile user/multimedia contents. As a result, re-
cent research has shifted its primary attention to DNN-based frame-
works to monitor and forecast the popularity of content using its his-
torical request pattern. A critical aspect of a DNN-based popularity
prediction architecture is its ability to accurately capture both tempo-
ral and spatial correlations within the time-variant request patterns of
multiple contents. While the temporal correlation illustrates the vari-
ation of users’ preferences over time, spatial correlation reflects the
dependency between different multimedia contents. The majority of
works in this field [18–21], however, are not appropriately designed
to simultaneously capture both dependencies. This necessitates an
urgent quest to develop and design a new and innovative popularity
prediction architecture, which is the focus of this paper.
Literature Review: Recently, a variety of promising strategies have
been designed to forecast the popularity of multimedia contents with
the application to MEC networks. In [25], an auto-encoder architec-
ture was proposed to improve content popularity prediction by learn-
ing the latent representation of historical request patterns of contents.
To boost the decision-making capabilities of caching strategies, Re-
inforcement Learning (RL) [26, 27] and Convolutional Neural Net-
work (CNN) [28]-based caching frameworks were introduced to ex-
ploit the contextual information of users. Despite all the benefits
that come from the aforementioned works, they relied on a common
assumption that the content popularity/historical request patterns of
contents would remain unchanged over time, which is not applicable
in highly dynamic practical systems.
arXiv:2210.15125v1 [cs.LG] 27 Oct 2022