1,027 research outputs found
The Role of Parked Cars in Content Downloading for Vehicular Networks
When it comes to content access using Inter-Vehicle Communication (IVC),
data will mostly flow
through Road Side Units (RSUs), deployed in our cities. Unfortunately, the RSU
coverage is expected to be rather scattered. Instead of relying on RSUs only,
the paper investigate the possibility of
exploiting parked vehicles to extend the RSU service coverage. Our
approach leverages optimization models aiming at maximizing the
freshness of content that downloaders retrieve, the efficiency in
the utilization of radio resources, and the fairness in exploiting the
energy resources of parked vehicles. The latter is constrained so as not to
excessively drain parked vehicle batteries.
Our approach provides an estimate of the system
performance, even in those cases where users may only be willing
to lease a limited amount of their battery capacity to extend RSU coverage.
Our optimization-based results are validated by comparing them against ns-3
simulations. Performance evaluation highlights that the use of parked
vehicles enhances the efficiency of the content downloading process by
25%-35% and can offload more than half the data traffic from RSUs,
with respect to the case where only moving cars are used as relays. Such gains
in performance come at a small cost in terms of battery utilization for
the parked vehicles, and they are magnified when a backbone of parked
vehicles can be formed
Cooperative video transmission strategies via caching in small-cell networks
Small-cell network is a promising solution to the high video traffic. However, it has some fundamental problems, i.e., high backhaul cost, quality of experience (QoE) and interference. To address these issues, we propose a cooperative transmission strategy for video transmission in small-cell networks with caching. In the scheme, each video file is encoded into segments using a maximum distance separable rateless code. Then, a portion of each segment is cached at a certain small-cell base station (SBS), so that the SBSs can cooperatively transmit these segments to users without incurring high backhaul cost. When there is only one active user in the network, a greedy algorithm is utilized to deliver the video-file segment from the SBS with good channel state to the user watching videos in real time. This reduces video freezes and improves the QoE. When there exist several active users, interference will appear among them. To deal with interference, interference alignment (IA) is adopted. Based on the scheme for a single user, the greedy algorithm and IA are combined to transmit video-file segments to these users, and the performance of the system can be significantly improved. Simulation results are presented to show the effectiveness of the proposed scheme
Thirty Years of Machine Learning: The Road to Pareto-Optimal Wireless Networks
Future wireless networks have a substantial potential in terms of supporting
a broad range of complex compelling applications both in military and civilian
fields, where the users are able to enjoy high-rate, low-latency, low-cost and
reliable information services. Achieving this ambitious goal requires new radio
techniques for adaptive learning and intelligent decision making because of the
complex heterogeneous nature of the network structures and wireless services.
Machine learning (ML) algorithms have great success in supporting big data
analytics, efficient parameter estimation and interactive decision making.
Hence, in this article, we review the thirty-year history of ML by elaborating
on supervised learning, unsupervised learning, reinforcement learning and deep
learning. Furthermore, we investigate their employment in the compelling
applications of wireless networks, including heterogeneous networks (HetNets),
cognitive radios (CR), Internet of things (IoT), machine to machine networks
(M2M), and so on. This article aims for assisting the readers in clarifying the
motivation and methodology of the various ML algorithms, so as to invoke them
for hitherto unexplored services as well as scenarios of future wireless
networks.Comment: 46 pages, 22 fig
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