545 research outputs found
Planning and dynamic spectrum management in heterogeneous mobile networks with QoE optimization
The radio and network planning and optimisation are continuous processes that do not end after the network has been launched. To achieve the best trade-offs, especially between quality and costs, operators make use of several coverage and capacity enhancement methods. The research from this thesis proposes methods such as the implementation of cell zooming and Relay Stations (RSs) with dynamic sleep modes and Carrier Aggregation (CA) for coverage and capacity enhancements.
Initially, a survey is presented on ubiquitous mesh networks implementation scenarios and an updated characterization of requirements for services and applications is proposed. The performance targets for the key parameters, delay, delay variation, information loss and throughput have been addressed for all types of services. Furthermore, with the increased competition, mobile operator’s success does not only depend on how good the offered Quality of Service (QoS) is, but also if it meets the end user’s expectations, i.e., Quality of Experience (QoE). In this context, a model for the mapping between QoS parameters and QoE has been proposed for multimedia traffic.
The planning and optimization of fixed Worldwide Interoperability for Microwave Access (WiMAX) networks with RSs in conjunction with cell zooming has been addressed. The challenging case of a propagation measurement-based scenario in the hilly region of Covilhã has been considered. A cost/revenue function has been developed by taking into account the cost of building and maintaining the infrastructure with the use of RSs. This part of the work also investigates the energy efficiency and economic implications of the use of power saving modes for RSs in conjunction with cell zooming. Assuming that the RSs can be switched-off or zoomed out to zero in periods when the traffic exchange is low, such as nights and weekends, it has been shown that energy consumption may be reduced whereas cellular coverage and capacity, as well as economic performance may be improved.
An integrated Common Radio Resource Management (iCRRM) entity is proposed that implements inter-band CA by performing scheduling between two Long Term Evolution – Advanced (LTE-A) Component Carriers (CCs). Considering the bandwidths available in Portugal, the 800 MHz and 2.6 GHz CCs have been considered whilst mobile video traffic is addressed. Through extensive simulations it has been found that the proposed multi-band schedulers overcome the capacity of LTE systems without CA. Result shown a clear improvement of the QoS, QoE and economic trade-off with CA
Deployment of Beyond 4G Wireless Communication Networks with Carrier Aggregation
With the growing demand for new blend of applications, the user’s dependency on the Internet is increasing day by day. Mobile Internet users are giving more attention to their own experience, especially in terms of communication reliability, high data rate and service stability on the move. This increase in the demand is causing saturation of existing radio frequency bands. To address these challenges, many researchers are finding the best approach, Carrier Aggregation (CA) is one of the newest innovations which seems to fulfil the demands of future spectrum, CA is one the most important feature for Long Term Evolution - Advanced. In direction to get the upcoming International Mobile Telecommunication Advanced (IMT-Advanced) mobile requirements 1 Gb/s peak data rate, the CA scheme is presented by 3GPP to sustain high data rate using widespread frequency bandwidth up to 100 MHz. Technical issues containing the aggregation structure, its implementation, deployment scenarios, control signal technique and challenges for CA technique in LTE-Advanced, with consideration backward compatibility are highlighted. Performance evaluation in macrocellular scenarios through a simulation approach shows the benefits of applying CA and low-complexity multi-band schedulers in service quality and system capacity enhancement. The Enhanced multi-band scheduler is less complex than the General multi-band scheduler and performs better for cell radius longer than 1800 m (and a PLR threshold of 2%).This work is funded by FCT/MCTES through national funds and when applicable co-funded EU funds under the project UIDB/EEA/50008/2020, COST CA 15104 IRACON, ORCIP and CONQUEST (CMU/ECE/0030/2017),
TeamUp5G project has received funding from the European Union’s Horizon
2020 research and innovation programme under the Marie Skłodowska-Curie
project number 813391.info:eu-repo/semantics/acceptedVersio
Optimization of 5G Second Phase Heterogeneous Radio Access Networks with Small Cells
Due to the exponential increase in high data-demanding applications and their services per
coverage area, it is becoming challenging for the existing cellular network to handle the massive
sum of users with their demands. It is conceded to network operators that the current
wireless network may not be capable to shelter future traffic demands. To overcome the challenges
the operators are taking interest in efficiently deploying the heterogeneous network.
Currently, 5G is in the commercialization phase. Network evolution with addition of small
cells will develop the existing wireless network with its enriched capabilities and innovative
features. Presently, the 5G global standardization has introduced the 5G New Radio (NR) under
the 3rd Generation Partnership Project (3GPP). It can support a wide range of frequency
bands (<6 GHz to 100 GHz).
For different trends and verticals, 5G NR encounters, functional splitting and its cost evaluation
are well-thought-out. The aspects of network slicing to the assessment of the business
opportunities and allied standardization endeavours are illustrated. The study explores the
carrier aggregation (Pico cellular) technique for 4G to bring high spectral efficiency with the
support of small cell massification while benefiting from statistical multiplexing gain. One
has been able to obtain values for the goodput considering CA in LTE-Sim (4G), of 40 Mbps
for a cell radius of 500 m and of 29 Mbps for a cell radius of 50 m, which is 3 times higher
than without CA scenario (2.6 GHz plus 3.5 GHz frequency bands).
Heterogeneous networks have been under investigation for many years. Heterogeneous network
can improve users service quality and resource utilization compared to homogeneous
networks. Quality of service can be enhanced by putting the small cells (Femtocells or Picocells)
inside the Microcells or Macrocells coverage area. Deploying indoor Femtocells for 5G
inside the Macro cellular network can reduce the network cost. Some service providers have
started their solutions for indoor users but there are still many challenges to be addressed.
The 5G air-simulator is updated to deploy indoor Femto-cell with proposed assumptions with
uniform distribution. For all the possible combinations of apartments side length and transmitter
power, the maximum number of supported numbers surpassed the number of users
by more than two times compared to papers mentioned in the literature. Within outdoor environments,
this study also proposed small cells optimization by putting the Pico cells within
a Macro cell to obtain low latency and high data rate with the statistical multiplexing gain of
the associated users.
Results are presented 5G NR functional split six and split seven, for three frequency bands
(2.6 GHz, 3.5GHz and 5.62 GHz). Based on the analysis for shorter radius values, the best
is to select the 2.6 GHz to achieve lower PLR and to support a higher number of users, with
better goodput, and higher profit (for cell radius u to 400 m). In 4G, with CA, from the
analysis of the economic trade-off with Picocell, the Enhanced multi-band scheduler EMBS
provide higher revenue, compared to those without CA. It is clearly shown that the profit of
CA is more than 4 times than in the without CA scenario. This means that the slight increase
in the cost of CA gives back more than 4-time profit relatively to the ”without” CA scenario.Devido ao aumento exponencial de aplicações/serviços de elevado débito por unidade de
área, torna-se bastante exigente, para a rede celular existente, lidar com a enormes quantidades
de utilizadores e seus requisitos. É reconhecido que as redes móveis e sem fios atuais
podem não conseguir suportar a procura de tráfego junto dos operadores. Para responder
a estes desafios, os operadores estão-se a interessar pelo desenvolvimento de redes heterogéneas
eficientes. Atualmente, a 5G está na fase de comercialização. A evolução destas
redes concretizar-se-á com a introdução de pequenas células com aptidões melhoradas e
características inovadoras. No presente, os organismos de normalização da 5G globais introduziram
os Novos Rádios (NR) 5G no contexto do 3rd Generation Partnership Project
(3GPP). A 5G pode suportar uma gama alargada de bandas de frequência (<6 a 100 GHz).
Abordam-se as divisões funcionais e avaliam-se os seus custos para as diferentes tendências
e verticais dos NR 5G. Ilustram-se desde os aspetos de particionamento funcional da rede à
avaliação das oportunidades de negócio, aliadas aos esforços de normalização. Exploram-se
as técnicas de agregação de espetro (do inglês, CA) para pico células, em 4G, a disponibilização
de eficiência espetral, com o suporte da massificação de pequenas células, e o ganho
de multiplexagem estatística associado. Obtiveram-se valores do débito binário útil, considerando
CA no LTE-Sim (4G), de 40 e 29 Mb/s para células de raios 500 e 50 m, respetivamente,
três vezes superiores em relação ao caso sem CA (bandas de 2.6 mais 3.5 GHz).
Nas redes heterogéneas, alvo de investigação há vários anos, a qualidade de serviço e a utilização
de recursos podem ser melhoradas colocando pequenas células (femto- ou pico-células)
dentro da área de cobertura de micro- ou macro-células). O desenvolvimento de pequenas
células 5G dentro da rede com macro-células pode reduzir os custos da rede. Alguns prestadores
de serviços iniciaram as suas soluções para ambientes de interior, mas ainda existem
muitos desafios a ser ultrapassados. Atualizou-se o 5G air simulator para representar a
implantação de femto-células de interior com os pressupostos propostos e distribuição espacial
uniforme. Para todas as combinações possíveis do comprimento lado do apartamento, o
número máximo de utilizadores suportado ultrapassou o número de utilizadores suportado
(na literatura) em mais de duas vezes. Em ambientes de exterior, propuseram-se pico-células
no interior de macro-células, de forma a obter atraso extremo-a-extremo reduzido e taxa de
transmissão dados elevada, resultante do ganho de multiplexagem estatística associado.
Apresentam-se resultados para as divisões funcionais seis e sete dos NR 5G, para 2.6 GHz,
3.5GHz e 5.62 GHz. Para raios das células curtos, a melhor solução será selecionar a banda
dos 2.6 GHz para alcançar PLR (do inglês, PLR) reduzido e suportar um maior número de
utilizadores, com débito binário útil e lucro mais elevados (para raios das células até 400 m).
Em 4G, com CA, da análise do equilíbrio custos-proveitos com pico-células, o escalonamento
multi-banda EMBS (do inglês, Enhanced Multi-band Scheduler) disponibiliza proveitos superiores
em comparação com o caso sem CA. Mostra-se claramente que lucro com CA é mais
de quatro vezes superior do que no cenário sem CA, o que significa que um aumento ligeiro
no custo com CA resulta num aumento de 4-vezes no lucro relativamente ao cenário sem CA
Cellular Planning and Optimization for 4G and 5G Mobile Networks
Cellular planning and optimization of mobile heterogeneous networks has been a topic of study
for several decades with a diversity of resources, such as analytical formulations and simulation
software being employed to characterize different scenarios with the aim of improving system
capacity. Furthermore, the world has now witnessed the birth of the first commercial 5G New
Radio networks with a technology that was developed to ensure the delivery of much higher data
rates with comparably lower levels of latency. In the challenging scenarios of 4G and beyond,
Carrier Aggregation has been proposed as a resource to allow enhancements in coverage and
capacity. Another key element to ensure the success of 4G and 5G networks is the deployment
of Small Cells to offload Macrocells. In this context, this MSc dissertation explores Small Cells
deployment via an analytical formulation, where metrics such as Carrier plus Noise Interference
Ratio, and physical and supported throughput are computed to evaluate the system´s capacity
under different configurations regarding interferers positioning in a scenario where Spectrum
Sharing is explored as a solution to deal with the scarcity of spectrum. One also uses the results
of this analyses to propose a cost/revenue optimization where deployment costs are estimated
and evaluated as well as the revenue considering the supported throughput obtained for the
three frequency bands studied, i.e., 2.6 GHz, 3.5 GHz and 5.62 GHz. Results show that, for a
project life time of 5 years, and prices for the traffic of order of 5€ per 1 GB, the system is
profitable for all three frequency bands, for distances up to 1335 m. Carrier Aggregation is also
investigated, in a scenario where the LTE-Sim packet level simulator is used to evaluate the use
of this approach while considering the use of two frequency bands i.e., 2.6 GHz and 800 MHz
to perform the aggregation with the scheduling of packets being performed via an integrated
common radio resource management used to compute Packet Loss Ratio, delay and goodput
under different scenarios of number of users and cell radius. Results of this analysis have been
compared to a scenario without Carrier Aggregation and it has been demonstrated that CA is
able to enhance capacity by reducing the levels of Packet Loss Ratio and delay, which in turn
increases the achievable goodput.O planeamento e otimização de redes de redes celulares heterogéneas tem sido um tópico de
investigação por várias décadas com diversas abordagens que incluem formulações analíticas e
softwares de simulação, sendo aplicados na caracterização de diferentes cenários, com o objetivo de melhorar a capacidade de sistema. Além disso, o mundo testemunhou o nascimento
das primeiras redes 5G New Radio, com uma tecnologia que foi desenvolvida com o objetivo de
garantir taxas de transferência de dados muito superiores, com níveis de latência comparativamente inferiores. Neste cenário de desafios pós-4G, a agregação de Espectro tem sido proposta
como uma solução para permitir melhorias na cobertura e capacidade do sistema. Outro ponto
para garantir o sucesso das redes 5G é a utilização de Pequenas Células para descongestionar
as Macro células. Neste contexto, esta dissertação de mestrado explora a utilização de Pequenas Células através de uma formulação analítica, onde se avaliam métricas como a relação
portadora-interferência-mais-ruído, débito binário e débito binário suportado, sob diferentes
configurações de posicionamento de interferentes em cenários onde a partilha de espectro é
explorada como uma solução para enfrentar a escassez de espectro. Os resultados dessa análise
são também considerados para propor uma otimização de custos/proveitos, onde os custos de
implantação são estimados e avaliados, assim como os proveitos ao se considerar o débito binário
suportado obtido para as três bandas de frequência em estudo, a saber, 2.6 GHz, 3.5 GHz e 5.62
GHz. Os resultados demonstram que, para um tempo de vida do projeto de 5 anos, e para preços
de tráfego de cerca de 5 € por GB, o sistema é lucrativo para as três bandas de frequência, para
distâncias até 1335 m. Também se investiga a agregação de espectro recorrendo ao simulador
de pacotes LTE-Sim para avaliar o uso de duas bandas de frequência, a saber, 2.6 GHz e 800
MHz, considerando agregação com a calendarização de pacotes por meio de um gestor comum
de recursos de rádio integrado, utilizado para computar a taxa de perda de pacotes, o atraso
e o débito binário na camada de aplicação, em cenários com diferentes valores de número de
utilizadores e raios das células. Os resultados dessa análise foram comparados com o desempenho de um cenário sem agregação. Foi demonstrado que a agregação é capaz de aumentar a
capacidade de sistema, ao reduzir os níveis de perda de pacotes e do atraso, o que por sua vez
possibilita a elevação dos níveis de débito binário atingidos
Review on Radio Resource Allocation Optimization in LTE/LTE-Advanced using Game Theory
Recently, there has been a growing trend toward ap-plying game theory (GT) to various engineering fields in order to solve optimization problems with different competing entities/con-tributors/players. Researches in the fourth generation (4G) wireless network field also exploited this advanced theory to overcome long term evolution (LTE) challenges such as resource allocation, which is one of the most important research topics. In fact, an efficient de-sign of resource allocation schemes is the key to higher performance. However, the standard does not specify the optimization approach to execute the radio resource management and therefore it was left open for studies. This paper presents a survey of the existing game theory based solution for 4G-LTE radio resource allocation problem and its optimization
Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks
Soaring capacity and coverage demands dictate that future cellular networks
need to soon migrate towards ultra-dense networks. However, network
densification comes with a host of challenges that include compromised energy
efficiency, complex interference management, cumbersome mobility management,
burdensome signaling overheads and higher backhaul costs. Interestingly, most
of the problems, that beleaguer network densification, stem from legacy
networks' one common feature i.e., tight coupling between the control and data
planes regardless of their degree of heterogeneity and cell density.
Consequently, in wake of 5G, control and data planes separation architecture
(SARC) has recently been conceived as a promising paradigm that has potential
to address most of aforementioned challenges. In this article, we review
various proposals that have been presented in literature so far to enable SARC.
More specifically, we analyze how and to what degree various SARC proposals
address the four main challenges in network densification namely: energy
efficiency, system level capacity maximization, interference management and
mobility management. We then focus on two salient features of future cellular
networks that have not yet been adapted in legacy networks at wide scale and
thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and
device-to-device (D2D) communications. After providing necessary background on
CoMP and D2D, we analyze how SARC can particularly act as a major enabler for
CoMP and D2D in context of 5G. This article thus serves as both a tutorial as
well as an up to date survey on SARC, CoMP and D2D. Most importantly, the
article provides an extensive outlook of challenges and opportunities that lie
at the crossroads of these three mutually entangled emerging technologies.Comment: 28 pages, 11 figures, IEEE Communications Surveys & Tutorials 201
Spectrum Sharing, Latency, and Security in 5G Networks with Application to IoT and Smart Grid
The surge of mobile devices, such as smartphones, and tables, demands additional capacity. On the other hand, Internet-of-Things (IoT) and smart grid, which connects numerous sensors, devices, and machines require ubiquitous connectivity and data security. Additionally, some use cases, such as automated manufacturing process, automated transportation, and smart grid, require latency as low as 1 ms, and reliability as high as 99.99\%. To enhance throughput and support massive connectivity, sharing of the unlicensed spectrum (3.5 GHz, 5GHz, and mmWave) is a potential solution. On the other hand, to address the latency, drastic changes in the network architecture is required. The fifth generation (5G) cellular networks will embrace the spectrum sharing and network architecture modifications to address the throughput enhancement, massive connectivity, and low latency.
To utilize the unlicensed spectrum, we propose a fixed duty cycle based coexistence of LTE and WiFi, in which the duty cycle of LTE transmission can be adjusted based on the amount of data. In the second approach, a multi-arm bandit learning based coexistence of LTE and WiFi has been developed. The duty cycle of transmission and downlink power are adapted through the exploration and exploitation. This approach improves the aggregated capacity by 33\%, along with cell edge and energy efficiency enhancement. We also investigate the performance of LTE and ZigBee coexistence using smart grid as a scenario.
In case of low latency, we summarize the existing works into three domains in the context of 5G networks: core, radio and caching networks. Along with this, fundamental constraints for achieving low latency are identified followed by a general overview of exemplary 5G networks. Besides that, a loop-free, low latency and local-decision based routing protocol is derived in the context of smart grid. This approach ensures low latency and reliable data communication for stationary devices.
To address data security in wireless communication, we introduce a geo-location based data encryption, along with node authentication by k-nearest neighbor algorithm. In the second approach, node authentication by the support vector machine, along with public-private key management, is proposed. Both approaches ensure data security without increasing the packet overhead compared to the existing approaches
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