359 research outputs found
LTE and Wi-Fi Coexistence in Unlicensed Spectrum with Application to Smart Grid: A Review
Long Term Evolution (LTE) is expanding its utilization in unlicensed band by
deploying LTE Unlicensed (LTEU) and Licensed Assisted Access LTE (LTE-LAA)
technology. Smart Grid can take the advantages of unlicensed bands for
achieving two-way communication between smart meters and utility data centers
by using LTE-U/LTE-LAA. However, both schemes must co-exist with the incumbent
Wi-Fi system. In this paper, several co-existence schemes of Wi-Fi and LTE
technology is comprehensively reviewed. The challenges of deploying LTE and
Wi-Fi in the same band are clearly addressed based on the papers reviewed.
Solution procedures and techniques to resolve the challenging issues are
discussed in a short manner. The performance of various network architectures
such as listenbefore- talk (LBT) based LTE, carrier sense multiple access with
collision avoidance (CSMA/CA) based Wi-Fi is briefly compared. Finally, an
attempt is made to implement these proposed LTEWi- Fi models in smart grid
technology.Comment: submitted in 2018 IEEE PES T&
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
Auction-Based Coopetition between LTE Unlicensed and Wi-Fi
Motivated by the recent efforts in extending LTE to the unlicensed spectrum,
we propose a novel spectrum sharing framework for the coopetition (i.e.,
cooperation and competition) between LTE and Wi-Fi in the unlicensed band.
Basically, the LTE network can choose to work in one of the two modes: in the
competition mode, it randomly accesses an unlicensed channel, and interferes
with the Wi-Fi access point using the same channel; in the cooperation mode, it
delivers traffic for the Wi-Fi users in exchange for the exclusive access of
the corresponding channel. Because the LTE network works in an
interference-free manner in the cooperation mode, it can achieve a much larger
data rate than that in the competition mode, which allows it to effectively
serve both its own users and the Wi-Fi users. We design a second-price reverse
auction mechanism, which enables the LTE provider and the Wi-Fi access point
owners (APOs) to effectively negotiate the operation mode. Specifically, the
LTE provider is the auctioneer (buyer), and the APOs are the bidders (sellers)
who compete to sell their channel access opportunities to the LTE provider. In
Stage I of the auction, the LTE provider announces a reserve rate. In Stage II
of the auction, the APOs submit their bids. We show that the auction involves
allocative externalities, i.e., the cooperation between the LTE provider and
one APO benefits other APOs who are not directly involved in this cooperation.
As a result, a particular APO's willingness to cooperate is affected by its
belief about other APOs' willingness to cooperate. This makes our analysis much
more challenging than that of the conventional second-price auction, where
bidding truthfully is a weakly dominant strategy. We show that the APOs have a
unique form of the equilibrium bidding strategies in Stage II, based on which
we analyze the LTE provider's optimal reserve rate in Stage I.Comment: 32 page
Fairness-Oriented Link Scheduling for a D2D-enabled LTE-U/Wi-Fi Coexistence Network
To avoid spectrum crunch and improve spectrum efficiency, the use of unlicensed spectra and the introduction of D2D communication will be areas of focus in communication development. However, in the existing unlicensed spectrum coexistence mechanism, different ways of communication are seen as hindering each other. In this paper, we deliberate the coexistence of a D2D-enabled LTE network with Wi-Fi under an unlicensed band. Unlike previous coexistence mechanisms, we allow co-channel transmission, and our goal is to make full use of the advantages of D2D proximity communication and achieve fairness in co-channel transmission. First, we modeled the coexistence network and derived the expressions coverage probability of all types of receivers. Based on the analytical model and simulation results, we prove that D2D communication can be exploited to achieve fairness requirements in co-channel transmission over the unlicensed band. We rephrase the fairness schedule problem as a mixed-integer nonlinear optimization problem for D2D density and transmit power, and we use an Ortho-MADS algorithm to solve it. The simulation results show that the proposed scheme can use D2D communication to improve the fairness of the system
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