793 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
Wi-Fi Coexistence with Duty Cycled LTE-U
Coexistence of Wi-Fi and LTE-Unlicensed (LTE-U) technologies has drawn
significant concern in industry. In this paper, we investigate the Wi-Fi
performance in the presence of duty cycle based LTE-U transmission on the same
channel. More specifically, one LTE-U cell and one Wi-Fi basic service set
(BSS) coexist by allowing LTE-U devices transmit their signals only in
predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend
the shared channel using the distributed coordination function (DCF) protocol
without cooperation with the LTE-U system or prior knowledge about the duty
cycle period or duty cycle of LTE-U transmission. We define the fairness of the
above scheme as the difference between Wi-Fi performance loss ratio
(considering a defined reference performance) and the LTE-U duty cycle (or
function of LTE-U duty cycle). Depending on the interference to noise ratio
(INR) being above or below -62dbm, we classify the LTE-U interference as strong
or weak and establish mathematical models accordingly. The average throughput
and average service time of Wi-Fi are both formulated as functions of Wi-Fi and
LTE-U system parameters using probability theory. Lastly, we use the Monte
Carlo analysis to demonstrate the fairness of Wi-Fi and LTE-U air time sharing
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