An Analytical Cost-Optimal Cloudlet Placement Framework over Fiber-Wireless Networks with Quasi-Convex Latency Constraint

Abstract

To meet the low-latency constraints arising from future smart mobile devices, Internet-of-Things, and 5G applications, major interest is currently given to the integration of centralized cloud computing and distributed edge computing infrastructures to deliver higher performance and reliability to edge devices in accessing mobile cloud services. The three-tier network architecture arising from cloud, cloudlet, and edge-devices can handle miscellaneous latency requirements for both latency-sensitive and latency-tolerant applications more efficiently than conventional two-tier networks. In this paper, we primarily focus on the static cloudlet network planning problem and propose an analytical hybrid cost-optimization framework for optimal cloudlet placement. We formulate this problem as a convex optimization problem and solve by using Karush-Kuhn-Tucker (KKT) conditions, and show that this framework can be evaluated without any scalability issues observed with integer programming based frameworks for large datasets. Moreover, we derive user-friendly closed form expressions that provide a first-hand estimation of cloudlet deployment cost depending on a few important network parameters like split-ratio, population density, and network bandwidth. Finally, we also show that the optimal solution of this analytical framework can be considered as a tight lower bound of the optimal solutions of integer programming based frameworks and makes a better cloudlet installation cost estimation compared to other existing frameworks.Electronics 2019, 8, 404 2 of 18 of cloudlet computing similar to fog and mobile-edge computing, where cloudlets are considered as trusted, resource-rich computer or cluster of computers. Nonetheless, cloudlets are designed to be self-managing and function with low-context-awareness. Hence, they are most suitable for deployment in adversarial environments [3].The authors of [4] showed that the system performance in terms of expected latency for the requested jobs from a single-hop cloudlet server is always better than a distant cloud server for low-latency applications. Thus, the optimal placement of cloudlets over wireless access networks seemed to be an important research problem to enhance the system performance. Along with the wireless access networks, researchers started to focus on optical and fiber-wireless (FiWi) access networks for edge-computing solutions deployment due to their wide deployment coverage, low cost per bit, very high data transmission bandwidth, efficient network virtualization and network scalability [5]. The time-division multiplexed passive optical network (TDM-PON) has also been considered as a front/back-haul support for wireless access network, i.e., access technologies like Radio-over-Fiber (RoF), WiFi, LTE-A and millimeter-wave (mmWave) can be integrated with optical network units (ONUs) for a higher user coverage [6].A static cloudlet placement framework considers that the network is static in time, i.e., it does not consider user mobility and virtual machine (VM) mobil...

Evolutionary Approaches to Fog Node Placement in LV Distribution Networks

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A Long-Term Cost-Oriented Cloudlet Planning Method in Wireless Metropolitan Area Networks

“…For more general cases, [15,16] studied the placement of heterogeneous cloudlets with different amounts of computation resources. Mondal et al [17] aimed to minimize the cloudlet installation cost by carefully planning cloudlet placement. However, the network is assumed to be static without considering users' movement.…”

“…Intuitively, constraint (16) indicates that if there is a cloudlet co-located with AP a i , there must be at least one server at AP a i . Constraint (17) implies that if requests via AP a j are handled at AP a i , there must be a cloudlet co-located with AP a i .…”

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“…Microwave photonic link (MPL), microwave transmission over an optical fiber, or radio over fiber (RoF) are considered as good solutions for high speed wireless transmission [1][2][3][4][5][6][7][8][9][10] due to its low cost, its simple system architecture, its anti-interference, its large bandwidth, its low transmission loss, and its low power consumption. With the increase of new optical communication system [11][12][13][14] services, the ultra-high speed and high spectrum efficiency have become primary demands for improving microwave photonic transmission.…”