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| 2. |
- Boccardi, Federico, et al.
(författare)
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Why to Decouple the Uplink and Downlink in Cellular Networks and How To Do It
- 2016
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Ingår i: IEEE Communications Magazine. - : IEEE. - 0163-6804 .- 1558-1896. ; 54:3, s. 110-117
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Tidskriftsartikel (refereegranskat)abstract
- Ever since the inception of mobile telephony, the downlink and uplink of cellular networks have been coupled, that is, mobile terminals have been constrained to associate with the same base station in both the downlink and uplink directions. New trends in network densification and mobile data usage increase the drawbacks of this constraint, and suggest that it should be revisited. In this article we identify and explain five key arguments in favor of downlink/uplink decoupling based on a blend of theoretical, experimental, and architectural insights. We then overview the changes needed in current LTE-A mobile systems to enable this decoupling, and then look ahead to fifth generation cellular standards. We demonstrate that decoupling can lead to significant gains in network throughput, outage, and power consumption at a much lower cost compared to other solutions that provide comparable or lower gains.
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| 3. |
- Kang, Du Ho
(författare)
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Interference Coordination for Low-cost Indoor Wireless Systems in Shared Spectrum
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mobile broadband services have become a big success over the last several years. Innovative, smart handsets have caused explosive traffic growth which has led to a severe capacity shortage. Since the majority of traffic originates from indoor locations or hotspots, significant invest- ment in indoor wireless infrastructure is predicted in order to resolve the capacity problem. While existing public operators mainly focus on high-mobility wide-area services, non-traditional local access providers (LAPs) such as facility owners are more and more interested in high data rate indoor services for their employees or customers. An obstacle is that they do not have access to dedicated spectrum. One proposal is spectrum sharing between LAPs. In shared spectrum, interference management emerges as a key technical challenge, and this becomes more critical as indoor systems become increasingly dense.This thesis concentrates on the interference management problem when spectrum is shared between high-density indoor wireless systems. There are two different design directions which require different system architectures. A Wi-Fi or femtocell system works in a fully uncoordinated manner without any inter-cell signaling. This allows high network scalability with cheap devices but leads to poor performance. Alter- natively, advanced interference coordination can be used. It certainly improves the performance; however, it usually requires expensive infras- tructure for real-time information exchange. A key question asked in this thesis is if the interference coordination gives sufficient economic gain to a LAP in terms of a total deployment cost. In order to answer this question, we first develop a conceptual framework to define and compare various levels of coordination. Then, we measure the re- quired number of access points (APs) at a given area capacity demand to estimate the economic gain.The coordination decision problem for a LAP is divided into two. Firstly, the LAP needs to choose the right level of coordination within its own network. Secondly, it determines whether or not to cooperate with neighboring LAPs for coordinating interference across the net- works. Regarding the intra-network decision, the comparison ranges from uncoordinated CSMA/CA to ideal interference cancellation. We find the total deployment cost of the uncoordinated CSMA/CA network soars when an area capacity requirement exceeds a certain threshold. The performance gain of the ideal coordination does not pay off the cost of high-speed backhaul because walls effectively suppress interference. Therefore, the most viable approach in a typical indoor environment is using dynamic coordination schemes via existing backhauls, for example Ethernet or xDSL. As for the cooperation decision, our major finding is that non-cooperative spectrum sharing is feasible provided that the transmit power of the APs is properly regulated. Although cooperation with advanced inter-network coordination schemes brings about cost savings, it is not sufficient to overcome practical barriers to a cooperation agreement especially when the capacity demand is high.
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| 4. |
- Laya, Andres, et al.
(författare)
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Green MTC, M2M, Internet of Things
- 2015
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Ingår i: Green Communications. - Chichester, UK : John Wiley & Sons. - 9781118759257 ; , s. 217-236
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Bokkapitel (refereegranskat)abstract
- The capability of having any type of object interconnected and Internet-connected creates an unprecedented access and exchange of information that has been baptized as the Internet of Things (IoT). With the advancement of integrated technologies, improved batteries, and electronic miniaturization, everyday things will be equipped with sensors and microprocessors to collect information around them and execute smart applications. In addition, they will be able to communicate with each other. The IoT has the potential to revolutionize innovations; create new products, services, business; and reshape consumer’s behavior. IoT represents a major player for the future of Information and Communications Technologies (ICT).The development of the IoT must be environment friendly. ICT have shown to be a key contributor to global warming and environmental pollution; it is predicted that the global greenhouse gas (GHG) emissions from ICT will account for 12% of all emissions by 2020 at a growth rate of 6% per year. Therefore, it is mandatory to develop environmentally friendly - or “green” - technologies for the IoT, and ICT in general.Machine-to-Machine (M2M) communications constitute a fundamental part of the IoT. The term M2M refers to the exchange of data between two or more entities, objects, or machines that do not necessarily need human interaction. The envisioned market for such kind of communications is broader than the one traditional human-based communications in terms of number of users and variety of applications. Some forecasts predict figures up to 50 billion machines that will be connecting to communication networks by 2020. This is a very big number compared to the entire world population of around 7 billion people. Therefore, there are some challenges that need to be addressed in order to fully supportM2Mservices in current communication networks. From the technical point of view, M2M communications are substantially different from Human-to-Human (H2H) communications. For example, network operators should provide communication services at low cost in order to face the low Average Revenue Per User (ARPU). Despite the large number of expected M2M connections, most of them will generate very little and infrequent data traffic. Communication networks shall also provide suitable congestion and overload control solutions in order to handle a huge number of simultaneous connections. Features such as low mobility, time-controlled data delivery, group-based policing and addressing, low connection delays, and a wide variety of Quality of Service requirements are among other challenges that need to be addressed. All of them must have the “green” concept embedded. In order to ensure that devices can operate autonomously for years or even decades without human intervention, it is necessary to provide networks with highly efficient communication protocols. This is the main focus of this chapter.The European Telecommunications Standards Institute (ETSI) created in 2009 a dedicated technical committee to identify key M2M use cases, understand the service requirements, and promote standards for the complete end-to-end M2M functional architecture. Later, in 2012, the global One M2M project was also established by ETSI, with other international standardization bodies, in order to define M2M standards that can accelerate the deployment and success of M2M applications.
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| 5. |
- Lema, Maria A., et al.
(författare)
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Business Case and Technology Analysis for 5G Low Latency Applications
- 2017
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Ingår i: IEEE Access. - : IEEE. - 2169-3536. ; 5, s. 5917-5935
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Tidskriftsartikel (refereegranskat)abstract
- A large number of new consumer and industrial applications are likely to change the classic operator's business models and provide a wide range of new markets to enter. This paper analyzes the most relevant 5G use cases that require ultra-low latency, from both technical and business perspectives. Low latency services pose challenging requirements to the network, and to fulfill them, operators need to invest in costly changes in their network. In this sense, it is not clear whether such investments are going to be amortized with these new business models. In light of this, specific applications and requirements are described and the potential market benefits for operators are analyzed. Conclusions show that the operators have clear opportunities to add value and position themselves strongly with the increasing number of services to be provided by 5G.
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| 6. |
- Marinchenko, Oleg, et al.
(författare)
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BuNGee project overview
- 2011
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Ingår i: IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS 2011). - 9781457716928
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Konferensbidrag (refereegranskat)abstract
- The BuNGee FP7 project is looking at achieving throughput densities substantially higher than available with today‘s systems. The project addresses this goal by a combination of techniques: below-rooftop access base stations and a unique feeding architecture using a combination of licensed in-band and out-of-band license exempt spectrum. Very high capacity feeding hubs with high-order spatial reuse are created using multi-beam antennas and advanced MIMO techniques, using millimeter waves.
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| 7. |
- Orsino, Antonino, et al.
(författare)
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Effects of Heterogeneous Mobility on D2D- and Drone-Assisted Mission-Critical MTC in 5G
- 2017
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Ingår i: IEEE Communications Magazine. - : IEEE Press. - 0163-6804 .- 1558-1896. ; 55:2, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- mcMTC is starting to play a central role in the industrial Internet of Things ecosystem and have the potential to create high-revenue businesses, including intelligent transportation systems, energy/ smart grid control, public safety services, and high-end wearable applications. Consequently, in the 5G of wireless networks, mcMTC have imposed a wide range of requirements on the enabling technology, such as low power, high reliability, and low latency connectivity. Recognizing these challenges, the recent and ongoing releases of LTE systems incorporate support for low-cost and enhanced coverage, reduced latency, and high reliability for devices at varying levels of mobility. In this article, we examine the effects of heterogeneous user and device mobility - produced by a mixture of various mobility patterns - on the performance of mcMTC across three representative scenarios within a multi-connectivity 5G network. We establish that the availability of alternative connectivity options, such as D2D links and drone-assisted access, helps meet the requirements of mcMTC applications in a wide range of scenarios, including industrial automation, vehicular connectivity, and urban communications. In particular, we confirm improvements of up to 40 percent in link availability and reliability with the use of proximate connections on top of the cellular-only baseline.
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| 8. |
- Tataria, Harsh, et al.
(författare)
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6G Wireless Systems: Vision, Requirements, Challenges, Insights, and Opportunities
- 2021
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Ingår i: Proceedings of the IEEE. - 0018-9219. ; 109:7, s. 1166-1199
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Tidskriftsartikel (refereegranskat)abstract
- Mobile communications have been undergoing a generational change every ten years or so. However, the time difference between the so-called "G's" is also decreasing. While fifth-generation (5G) systems are becoming a commercial reality, there is already significant interest in systems beyond 5G, which we refer to as the sixth-generation (6G) of wireless systems. In contrast to the already published papers on the topic, we take a top-down approach to 6G. More precisely, we present a holistic discussion of 6G systems beginning with lifestyle and societal changes driving the need for next generation networks. This is followed by a discussion into the technical requirements needed to enable 6G applications, based on which we dissect key challenges, as well as possibilities for practically realizable system solutions across all layers of the Open Systems Interconnection stack (i.e., from applications to the physical layer). Since many of the 6G applications will need access to an order-of-magnitude more spectrum, utilization of frequencies between 100 GHz and 1 THz becomes of paramount importance. As such, the 6G eco-system will feature a diverse range of frequency bands, ranging from below 6 GHz up to 1 THz. We comprehensively characterize the limitations that must be overcome to realize working systems in these bands; and provide a unique perspective on the physical, as well as higher layer challenges relating to the design of next generation core networks, new modulation and coding methods, novel multiple access techniques, antenna arrays, wave propagation, radio-frequency transceiver design, as well as real-time signal processing. We rigorously discuss the fundamental changes required in the core networks of the future, such as the redesign or significant reduction of the transport architecture that serves as a major source of latency for time-sensitive applications. This is in sharp contrast to the present hierarchical network architectures, which are not suitable to realize many of the anticipated 6G services. While evaluating the strengths and weaknesses of key candidate 6G technologies, we differentiate what may be practically achievable over the next decade, relative to what is possible in theory. Keeping this in mind, we present concrete research challenges for each of the discussed system aspects, providing inspiration for what follows.
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