Cellular and Wireless Networks
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ItemSpace Time Coding Over a Multiple-Channel Free Space Optical Link( 2020-01-07)Free space optical (FSO) communications in the atmosphere are characterized by additive white Gaussian noise (AWGN) and turbulent fading. We propose a combination of spatial and temporal forward error correction (FEC) coding to instantaneously correct for long-duration fades over a multiple channel link. We simulate this over a turbulent channel and identify the probability of outage of such a channel as the most significant channel parameter.
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ItemCapacity Estimation for Error Correction Code-based Embedding in Adaptive Rate Wireless Communication Systems( 2020-01-07)In this paper, we explore the performance of error correction code-based embedding in adaptive rate wireless communication systems. We first develop a model to illustrate the relationship between the selected modulation and coding scheme index, the current channel state, and the embedding capacity. Extensive simulations facilitate the development of expressions to describe the estimated embedding capacity for the proposed scheme when implemented within the single carrier physical layer of the IEEE 802.11ad, directional multi-Gigabit standard. We further identify and characterize various types of distortion and describe additional constraints that may serve to reduce the available embedding margin and overall embedding capacity.
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ItemTiming Management in 5G and Its Implications for Location Privacy( 2020-01-07)The fifth generation (5G) technological leap has arrived, bringing with it promises of incredible data rates and never before seen precision in location accuracy. However this self-same precision carries with it the significant question: how will it be protected? These questions form the underlying motivation for this article where we examine 5G architecture which employs a radio access part commonly termed a cloud or centralized radio access network (C-RAN). The C-RAN centralizes higher-level physical layer processes while keeping lowlevel processes distributed throughout the physical network. We show how this architecture both increases location-based privacy through improved physical-layer security, but creates new privacy concerns via the extension of the radio access network through fronthauls connecting data transfer among low and high-level processing. Concurrently, the proposed 5G variable subcarrier spacing further exacerbates the former point. Through simulation we quantify the decrease in location privacy given the aforementioned considerations. It is shown that location privacy is inversely proportional to subcarrier spacing for user equipment (UE) connected to multiple 5G access points. Specifically, for a (UE) using the widest allowable subcarrier spacing location privacy drops to approximately three meters.
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ItemEfficient Mobile Edge Computing for Mobile Internet of Thing in 5G Networks( 2020-01-07)We study the off-line efficient mobile edge computing (EMEC) problem for a joint computing to process a task both locally and remotely with the objective of minimizing the finishing time. When computing remotely, the time will include the communication and computing time. We first describe the time model, formulate EMEC, prove NP-completeness of EMEC, and show the lower bound. We then provide an integer linear programming (ILP) based algorithm to achieve the optimal solution and give results for small-scale cases. A fully polynomial-time approximation scheme (FPTAS), named Approximation Partition (AP), is provided through converting ILP to the subset sum problem. Numerical results show that both the total data length and the movement have great impact on the time for mobile edge computing. Numerical results also demonstrate that our AP algorithm obtain the finishing time, which is close to the optimal solution.
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