80,771 research outputs found
A Multi-Service Oriented Multiple-Access Scheme for Next-Generation Mobile Networks
One of the key requirements for fifth-generation (5G) cellular networks is
their ability to handle densely connected devices with different quality of
service (QoS) requirements. In this article, we present multi-service oriented
multiple access (MOMA), an integrated access scheme for massive connections
with diverse QoS profiles and/or traffic patterns originating from both
handheld devices and machine-to-machine (M2M) transmissions. MOMA is based on
a) stablishing separate classes of users based on relevant criteria that go
beyond the simple handheld/M2M split, b) class dependent hierarchical spreading
of the data signal and c) a mix of multiuser and single-user detection schemes
at the receiver. Practical implementations of the MOMA principle are provided
for base stations (BSs) that are equipped with a large number of antenna
elements. Finally, it is shown that such a
massive-multiple-input-multiple-output (MIMO) scenario enables the achievement
of all the benefits of MOMA even with a simple receiver structure that allows
to concentrate the receiver complexity where effectively needed.Comment: 6 pages, 3 figures, accepted to the European Conference on Networks
and Communications (EuCNC 2016
Scheduling strategies for LTE uplink with flow behaviour analysis
Long Term Evolution (LTE) is a cellular technology developed to support\ud
diversity of data traffic at potentially high rates. It is foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key\ud
mechanism in the LTE traffic handling is the packet scheduler, which is in charge of allocating resources to active flows in both the frequency and time dimension. In this paper we present a performance comparison of two distinct scheduling schemes for LTE uplink (fair fixed assignment and fair work-conserving) taking into account both packet level characteristics and flow level dynamics due to the random user behaviour. For that purpose, we apply a combined analytical/simulation approach which enables fast evaluation of performance measures such as mean flow transfer times manifesting the impact of resource allocation strategies. The results show that the resource allocation strategy has a crucial impact on performance and that some trends are observed only if flow level dynamics are considered
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
Link power coordination for energy conservation in complex communication networks
Communication networks consume huge, and rapidly growing, amount of energy.
However, a lot of the energy consumption is wasted due to the lack of global
link power coordination in these complex systems. This paper proposes several
link power coordination schemes to achieve energy-efficient routing by
progressively putting some links into energy saving mode and hence aggregating
traffic during periods of low traffic load. We show that the achievable energy
savings not only depend on the link power coordination schemes, but also on the
network topologies. In the random network, there is no scheme that can
significantly outperform others. In the scale-free network, when the largest
betweenness first (LBF) scheme is used, phase transition of the networks'
transmission capacities during the traffic cooling down phase is observed.
Motivated by this, a hybrid link power coordination scheme is proposed to
significantly reduce the energy consumption in the scale-free network. In a
real Internet Service Provider (ISP)'s router-level Internet topology, however,
the smallest betweenness first (SBF) scheme significantly outperforms other
schemes.Comment: 6 pages, 4 figure
Analysis of packet scheduling for UMTS EUL - design decisions and performance evaluation
The UMTS Enhanced Uplink (EUL) provides higher capacity, increased data rates and smaller latency on the communication link from users towards the network. In this paper we present a performance comparison of three distinct EUL scheduling schemes (one-by-one, partial parallel and full parallel) taking into account both the packet level characteristics and the flow level dynamics due to the (random) user behaviour.\ud
Using a very efficient hybrid analytical and simulation approach we analyse the three schemes with respect to performance measures such as mean file transfer time and fairness. In UMTS, a significant part of the system capacity will be used to support non-elastic voice traffic. Hence, part of our investigation is dedicated to the effects that the volume of voice traffic has on the performance of the elastic traffic supported by the EUL. Finally, we evaluate the impact that implementation specifics of a full parallel scheduler has on these measures.\ud
\ud
Our main conclusion is that our partial parallel scheduler, which is a hybrid between the one-by-one and full parallel, outperforms the other two schedulers in terms of mean flow transfer time, and is less sensitive to volume and nature of voice traffic. However, under certain circumstances, the partial parallel scheduler exhibits a somewhat lower fairness than the alternatives
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Survey of traffic control schemes and error control schemes for ATM networks
Among the techniques proposed for B-ISDN transfer mode, ATM concept is considered to be the most promising transfer technique because of its flexibility and efficiency. This paper surveys and reviews a number of topics related to ATM networks. Those topics cover congestion control, provision of multiple classes of traffic, and error control. Due to the nature of ATM networks, those issues are far more challenging than in conventional networks. Sorne of the more promising solutions to those issues are surveyed, and the corresponding results on performance are summarized. Future research problems in ATM protocol aspect are also presented
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