625 research outputs found
Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
Satellite Communication systems are a promising solution to extend and
complement terrestrial networks in unserved or under-served areas. This aspect
is reflected by recent commercial and standardisation endeavours. In
particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G,
Non-Terrestrial Networks aimed at deploying satellite systems either as a
stand-alone solution or as an integration to terrestrial networks in mobile
broadband and machine-type communication scenarios. However, typical satellite
channel impairments, as large path losses, delays, and Doppler shifts, pose
severe challenges to the realisation of a satellite-based NR network. In this
paper, based on the architecture options currently being discussed in the
standardisation fora, we discuss and assess the impact of the satellite channel
characteristics on the physical and Medium Access Control layers, both in terms
of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB)
and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis
shows that the main technical challenges are related to the PHY/MAC procedures,
in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic
Repeat reQuest (HARQ) and, depending on the considered service and
architecture, different solutions are proposed.Comment: Submitted to Transactions on Vehicular Technologies, April 201
On the Fundamental Limits of Random Non-orthogonal Multiple Access in Cellular Massive IoT
Machine-to-machine (M2M) constitutes the communication paradigm at the basis
of Internet of Things (IoT) vision. M2M solutions allow billions of multi-role
devices to communicate with each other or with the underlying data transport
infrastructure without, or with minimal, human intervention. Current solutions
for wireless transmissions originally designed for human-based applications
thus require a substantial shift to cope with the capacity issues in managing a
huge amount of M2M devices. In this paper, we consider the multiple access
techniques as promising solutions to support a large number of devices in
cellular systems with limited radio resources. We focus on non-orthogonal
multiple access (NOMA) where, with the aim to increase the channel efficiency,
the devices share the same radio resources for their data transmission. This
has been shown to provide optimal throughput from an information theoretic
point of view.We consider a realistic system model and characterise the system
performance in terms of throughput and energy efficiency in a NOMA scenario
with a random packet arrival model, where we also derive the stability
condition for the system to guarantee the performance.Comment: To appear in IEEE JSAC Special Issue on Non-Orthogonal Multiple
Access for 5G System
Analytic Analysis of Narrowband IoT Coverage Enhancement Approaches
The introduction of Narrowband Internet of Things (NB-IoT) as a cellular IoT
technology aims to support massive Machine-Type Communications applications.
These applications are characterized by massive connections from a large number
of low-complexity and low-power devices. One of the goals of NB-IoT is to
improve coverage extension beyond existing cellular technologies. In order to
do that, NB-IoT introduces transmission repetitions and different bandwidth
allocation configurations in uplink. These new transmission approaches yield
many transmission options in uplink. In this paper, we propose analytical
expressions that describe the influence of these new approaches in the
transmission. Our analysis is based on the Shannon theorem. The transmission is
studied in terms of the required Signal to Noise Ratio, bandwidth utilization,
and energy per transmitted bit. Additionally, we propose an uplink link
adaptation algorithm that contemplates these new transmission approaches. The
conducted evaluation summarizes the influence of these approaches. Furthermore,
we present the resulting uplink link adaptation from our proposed algorithm
sweeping the device's coverage.Comment: Accepted in the 2018 Global IoT Summit (GIoTS) conferenc
Optimized LTE Data Transmission Procedures for IoT: Device Side Energy Consumption Analysis
The efficient deployment of Internet of Things (IoT) over cellular networks,
such as Long Term Evolution (LTE) or the next generation 5G, entails several
challenges. For massive IoT, reducing the energy consumption on the device side
becomes essential. One of the main characteristics of massive IoT is small data
transmissions. To improve the support of them, the 3GPP has included two novel
optimizations in LTE: one of them based on the Control Plane (CP), and the
other on the User Plane (UP). In this paper, we analyze the average energy
consumption per data packet using these two optimizations compared to
conventional LTE Service Request procedure. We propose an analytical model to
calculate the energy consumption for each procedure based on a Markov chain. In
the considered scenario, for large and small Inter-Arrival Times (IATs), the
results of the three procedures are similar. While for medium IATs CP reduces
the energy consumption per packet up to 87% due to its connection release
optimization
NarrowBand IoT Data Transmission Procedures for Massive Machine Type Communications
Large-scale deployments of massive Machine Type Communications (mMTC)
involve several challenges on cellular networks. To address the challenges of mMTC, or
more generally, Internet of Things (IoT), the 3rd Generation Partnership Project has
developed NarrowBand IoT (NB-IoT) as part of Release 13. NB-IoT is designed to
provide better indoor coverage, support of a massive number of low-throughput devices,
with relaxed delay requirements, and lower-energy consumption. NB-IoT reuses Long
Term Evolution functionality with simplifications and optimizations. Particularly for small
data transmissions, NB-IoT specifies two procedures to reduce the required signaling:
one of them based on the Control Plane (CP), and the other on the User Plane (UP). In
this work, we provide an overview of these procedures as well as an evaluation of their
performance. The results of the energy consumption show both optimizations achieve
a battery lifetime extension of more than 2 years for a large range in the considered
cases, and up to 8 years for CP with good coverage. In terms of cell capacity relative to
SR, CP achieves gains from 26% to 224%, and UP ranges from 36% to 165%. The
comparison of CP and UP optimizations yields similar results, except for some specific
configurations.This work is partially supported by the Spanish
Ministry of Economy and Competitiveness and
the European Regional Development Fund (Projects TIN2013-46223-P, and TEC2016-76795-
C6-4-R), and the Spanish Ministry of Education,
Culture and Sport (FPU Grant 13/04833)
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