492,986 research outputs found
Survey of Spectrum Sharing for Inter-Technology Coexistence
Increasing capacity demands in emerging wireless technologies are expected to
be met by network densification and spectrum bands open to multiple
technologies. These will, in turn, increase the level of interference and also
result in more complex inter-technology interactions, which will need to be
managed through spectrum sharing mechanisms. Consequently, novel spectrum
sharing mechanisms should be designed to allow spectrum access for multiple
technologies, while efficiently utilizing the spectrum resources overall.
Importantly, it is not trivial to design such efficient mechanisms, not only
due to technical aspects, but also due to regulatory and business model
constraints. In this survey we address spectrum sharing mechanisms for wireless
inter-technology coexistence by means of a technology circle that incorporates
in a unified, system-level view the technical and non-technical aspects. We
thus systematically explore the spectrum sharing design space consisting of
parameters at different layers. Using this framework, we present a literature
review on inter-technology coexistence with a focus on wireless technologies
with equal spectrum access rights, i.e. (i) primary/primary, (ii)
secondary/secondary, and (iii) technologies operating in a spectrum commons.
Moreover, we reflect on our literature review to identify possible spectrum
sharing design solutions and performance evaluation approaches useful for
future coexistence cases. Finally, we discuss spectrum sharing design
challenges and suggest future research directions
Full-Duplex Cognitive Radio: A New Design Paradigm for Enhancing Spectrum Usage
With the rapid growth of demand for ever-increasing data rate, spectrum
resources have become more and more scarce. As a promising technique to
increase the efficiency of the spectrum utilization, cognitive radio (CR)
technique has the great potential to meet such a requirement by allowing
un-licensed users to coexist in licensed bands. In conventional CR systems, the
spectrum sensing is performed at the beginning of each time slot before the
data transmission. This unfortunately results in two major problems: 1)
transmission time reduction due to sensing, and 2) sensing accuracy impairment
due to data transmission. To tackle these problems, in this paper we present a
new design paradigm for future CR by exploring the full-duplex (FD) techniques
to achieve the simultaneous spectrum sensing and data transmission. With FD
radios equipped at the secondary users (SUs), SUs can simultaneously sense and
access the vacant spectrum, and thus, significantly improve sensing
performances and meanwhile increase data transmission efficiency. The aim of
this article is to transform the promising conceptual framework into the
practical wireless network design by addressing a diverse set of challenges
such as protocol design and theoretical analysis. Several application scenarios
with FD enabled CR are elaborated, and key open research directions and novel
algorithms in these systems are discussed
Iris: Deep Reinforcement Learning Driven Shared Spectrum Access Architecture for Indoor Neutral-Host Small Cells
We consider indoor mobile access, a vital use case for current and future
mobile networks. For this key use case, we outline a vision that combines a
neutral-host based shared small-cell infrastructure with a common pool of
spectrum for dynamic sharing as a way forward to proliferate indoor small-cell
deployments and open up the mobile operator ecosystem. Towards this vision, we
focus on the challenges pertaining to managing access to shared spectrum (e.g.,
3.5GHz US CBRS spectrum). We propose Iris, a practical shared spectrum access
architecture for indoor neutral-host small-cells. At the core of Iris is a deep
reinforcement learning based dynamic pricing mechanism that efficiently
mediates access to shared spectrum for diverse operators in a way that provides
incentives for operators and the neutral-host alike. We then present the Iris
system architecture that embeds this dynamic pricing mechanism alongside
cloud-RAN and RAN slicing design principles in a practical neutral-host design
tailored for the indoor small-cell environment. Using a prototype
implementation of the Iris system, we present extensive experimental evaluation
results that not only offer insight into the Iris dynamic pricing process and
its superiority over alternative approaches but also demonstrate its deployment
feasibility
Managing Shared Access to a Spectrum Commons
The open access, unlicensed or spectrum commons approach to managing shared access to RF spectrum offers many attractive benefits, especially when implemented in conjunction with and as a complement to a regime of marketbased, flexible use, tradable licensed spectrum ([Benkler02], [Lehr04], [Werbach03]). However, as a number of critics have pointed out, implementing the unlicensed model poses difficult challenges that have not been well-addressed yet by commons advocates ([Benjam03], [Faulhab05], [Goodman04], [Hazlett01]). A successful spectrum commons will not be unregulated, but it also need not be command & control by another name. This paper seeks to address some of the implementation challenges associated with managing a spectrum commons. We focus on the minimal set of features that we believe a suitable management protocol, etiquette, or framework for a spectrum commons will need to incorporate. This includes: (1) No transmit only devices; (2) Power restrictions; (3) Common channel signaling; (4) Mechanism for handling congestion and allocating resources among users/uses in times of congestion; (5) Mechanism to support enforcement (e.g., established procedures to verify protocol is in conformance); (6) Mechanism to support reversibility of policy; and (7) Protection for privacy and security. We explain why each is necessary, examine their implications for current policy, and suggest ways in which they might be implemented. We present a framework that suggests a set of design principles for the protocols that will govern a successful commons management regime. Our design rules lead us to conclude that the appropriate Protocols for a Commons will need to be more liquid ([Reed05]) than in the past: (1) Marketbased instead of C&C; (2) Decentralized/distributed; and, (3) Adaptive and flexible (Anonymous, distributed, decentralized, and locally responsive)
Enabling RAN Slicing Through Carrier Aggregation in mmWave Cellular Networks
The ever increasing number of connected devices and of new and heterogeneous
mobile use cases implies that 5G cellular systems will face demanding technical
challenges. For example, Ultra-Reliable Low-Latency Communication (URLLC) and
enhanced Mobile Broadband (eMBB) scenarios present orthogonal Quality of
Service (QoS) requirements that 5G aims to satisfy with a unified Radio Access
Network (RAN) design. Network slicing and mmWave communications have been
identified as possible enablers for 5G. They provide, respectively, the
necessary scalability and flexibility to adapt the network to each specific use
case environment, and low latency and multi-gigabit-per-second wireless links,
which tap into a vast, currently unused portion of the spectrum. The
optimization and integration of these technologies is still an open research
challenge, which requires innovations at different layers of the protocol
stack. This paper proposes to combine them in a RAN slicing framework for
mmWaves, based on carrier aggregation. Notably, we introduce MilliSlice, a
cross-carrier scheduling policy that exploits the diversity of the carriers and
maximizes their utilization, thus simultaneously guaranteeing high throughput
for the eMBB slices and low latency and high reliability for the URLLC flows.Comment: 8 pages, 8 figures. Proc. of the 18th Mediterranean Communication and
Computer Networking Conference (MedComNet 2020), Arona, Italy, 202
Beyond Coase: Emerging Technologies and Property Theory
In addition to prompting the development of the Coase Theorem, Ronald Coase’s landmark 1959 article on the Federal Communications Commission touched off a revolution in spectrum policy. Although one of Coase’s proposed reforms (that spectrum should be allocated through markets) has now become the conventional wisdom, his other principal recommendation (that governments stop dedicating portions of the spectrum to particular uses) has yet to be fully embraced. Drawing on spectrum as well as Internet traffic and electric power as examples, this Article argues that emerging technologies often reflect qualities that make defining property rights particularly difficult. These include the cumulative nature of interference, the presence of significant interdependencies, and the presence of significant geographic discontinuities in interference patterns, exacerbated by the localized nature of information. These technological considerations define the natural boundaries of property by creating transaction-free zones that must be encompassed within a single parcel. They also complicate defining property rights by making it difficult to identify and attribute harm to particular sources of interference. These challenges can make governance a more attractive solution than exclusion.
Other commentators have suggested that the failure of creating well-defined property rights in spectrum support wider use of open access regimes, citing the work of Elinor Ostrom and Michael Heller, or arguing that spectrum is not scarce. Ostrom’s work points out that governance of common property requires features that are quite inconsistent with open access, including a finely tailored and unequal allocation mechanism, strict internal monitoring, strong property protection to prevent outside interference, stability, and homogeneity. Heller’s theory of the anticommons is sometimes misinterpreted as being hostile towards property. Instead, it is better understood as condemning giving exclusionary rights in the same piece of property to multiple owners, all of whom must agree on any major decision. The primary solution to the anticommons is not open access, but rather unitization of the interests in a single owner. Moreover, bargaining over an anticommons is also properly modeled through the chicken (or snowdrift) game, which has more of a zero-sum, all-or-nothing quality, rather than opportunities for cooperation frustrated by a lack of trust that characterize the prisoner’s dilemma and traditional holdout behavior. The final argument, that spectrum is not scarce, simply cannot be squared with Shannon’s Law.
Instead the solution may lie in reconfiguring rights to increase owners’ ability to bargain towards workable solutions. A market maker controlling sufficient property and able to integrate local information could design a mechanism that can solve some of these problems. Property could also be reconfigured to provide more of the primitives needed to write effective contracts. Finally, these challenges, as well as the need to reduce information costs on third parties, provide an explanation for the persistence of use restrictions. In addition, continuing the fiction of government ownership of the spectrum may make it easier to reconfigure rights when necessary
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