Two-step Scheduling Algorithm Research Articles

Improved Jellyfish Algorithm-based multi-aspect task scheduling model for IoT tasks over fog integrated cloud environment

Corporations and enterprises creating IoT-based systems frequently use fog computing integrated with cloud computing to harness the benefits offered by both. These computing paradigms use virtualization and a pay-as-you-go strategy to provide IT resources, including CPU, memory, network and storage. Resource management in such a hybrid environment becomes a challenging task. This problem is exacerbated in the IoT environment, as it generates deadline-driven and heterogeneous data demanding real-time processing. This work proposes an efficient two-step scheduling algorithm comprising a Bi-factor classification task phase based on deadline and priority and a scheduling phase using an enhanced artificial Jellyfish Search Optimizer (JS) proposed as an Improved Jellyfish Algorithm (IJFA). The model considers a variety of cloud and fog resource parameters, including speed, capacity, task size, number of tasks, and number of virtual machines for resource provisioning in a fog integrated cloud environment. The model has been tested for the real-time task scenario with the number of tasks considering both the smaller workload and the relatively higher workload scenario matching the real-time situation. The model addresses the Quality of Service (QoS) parameters of minimizing the batch’s make-span time, lowering the batch execution costs, and increasing the resource utilization. Simulation results prove the effectiveness of the proposed model.

Structure-Free Broadcast Scheduling for Duty-Cycled Multihop Wireless Sensor Networks

Broadcasting is an essential operation in wireless networks for disseminating the message from the source node to all other nodes. Unfortunately, the problem of Minimum Latency Broadcast Scheduling (MLBS) in duty-cycled wireless sensor networks is not well studied. In existing works, the construction of broadcast tree and the scheduling of transmissions are conducted separately, where a tree-based structure is used as the input of the scheduling algorithm. Relying on a pre-determined tree may result in a much large latency even using the optimal scheduling method. Thus, the MLBS problem in duty-cycled WSNs without the above limitation is investigated in this paper. First, to avoid relying on a pre-determined structure, a two-step scheduling algorithm is proposed to construct the broadcast tree and compute a collision-free schedule simultaneously. To the best of our knowledge, this is the first work that can integrate these two kinds of operations together. Second, a novel transmission mode, i.e., concurrent broadcasting, is first introduced for wireless networks and several techniques are designed to further improve the broadcast latency. Third, the multiple messages broadcasting and all-to-all broadcasting algorithms, which can generate a series of broadcast schedules independently without a pre-determined tree, are also proposed by taking care of the collisions in both the current and the previous broadcast schedules. Finally, the theoretical analysis and experimental results demonstrate the efficiency of the proposed algorithms in terms of latency.

On the multiuser diversity of relay-aided downlink systems using reduced feedback.

We introduce an efficient multiuser scheduling method using amplify-and-forward relaying in relay-aided downlink systems, consisting of one base station (BS), one relay station, and multiple mobile stations (MSs). In our scheme, the BS opportunistically selects both the transmission mode, that is, either one- or two-hop transmission, and the desired user (i.e., the desired MS). Closed-form expressions for the average achievable rates are derived for the two transmission modes with multiuser scheduling, and its asymptotic solutions are also analyzed in the limit of large number of MSs. Based on the analysis, we propose a feedback-efficient two-step multiuser scheduling algorithm: the transmission mode selection followed by the user selection that only needs a partial feedback for instantaneous signal-to-noise ratios (SNRs) to the BS. We also analyze the average SNR condition such that the multiuser diversity gain is fully exploited for two-hop transmission. The proposed two-step scheduling algorithm exhibits the quite comparable achievable rates to those of the optimal one using full feedback information, while its required feedback information is reduced by half of the optimal one.

High-Throughput Scientific Workflow Scheduling under Deadline Constraint in Clouds

Cloud computing is a paradigm shift in service delivery that promises a leap in efficiency and flexibility in using computing resources. As cloud infrastructures are widely deployed around the globe, many data- and computeintensive scientific workflows have been moved from traditional high- performance computing platforms and grids to clouds. With the rapidly increasing number of cloud users in various science domains, it has become a critical task for the cloud service provider to perform efficient job scheduling while still guaranteeing the workflow completion time as specified in the Service Level Agreement (SLA). Based on practical models for cloud utilization, we formulate a delay-constrained workflow optimization problem to maximize resource utilization for high system throughput and propose a two-step scheduling algorithm to minimize the cloud overhead under a user-specified execution time bound. Extensive simulation results illustrate that the proposed algorithm achieves lower computing overhead or higher resource utilization than existing methods under the execution time bound, and also significantly reduces the total workflow execution time by strategically selecting appropriate mapping nodes for prioritized modules. Index Terms— computing

Cooperative MIMO multicell networks

Recently, the pressing desire to provide cost-effective solutions aimed at supporting high-throughput broadband wireless access with large-scale coverage has significantly changed the notion of the traditional cellular systems. Physical layer cooperation serves as an enabling technology for such a change. In latest cellular networks, neighboring infrastructure stations, such as base stations (BSs) or relay stations (RSs), share their communication resources to create virtual multiple-input multiple-output (MIMO) systems by means of distributed transmission and signal processing. Cooperative processing at the BSs promises to exceed the limits on spectral efficiency imposed by inter-cell interference, thereby allowing ever more aggressive frequency reuse patterns. On the other hand, cooperation between BSs and RSs, as well as among RSs, is expected to extend coverage and capacity of point-to-multipoint links between BSs and mobile stations in a highly economical fashion. However, to achieve such benefits in practice, numerous research challenges have to be still tackled. This special issue has come up with the intention of collecting cutting-edge research achievements in cooperative MIMO multicell systems. For this special issue, we have received 35 manuscript submissions altogether. After a careful review process, 10 manuscripts have been accepted for publication, which cover the following topics for cooperative MIMO multicell networks: channel modeling, power control and scheduling, interference management, protocol design and performance analysis, cost deployment, simulation tools and testbeds. A brief introduction of all the accepted manuscripts is reported in the following. In the manuscript “A Geometrical Three-Ring-Based Model for MIMO Mobile-to-Mobile Fading Channels in Cooperative Networks” by Talha and Patzold [1], a stochastic narrowband MIMO mobile-to-mobile reference channel model is derived in relay-based cooperative networks and exact closed-form expressions for different correlation functions are provided, under isotropic as well as non-isotropic scattering conditions. A stochastic simulation model is drawn from the reference model. It is shown that the cross-correlation functions of the simulation model closely approximate the corresponding ones of the reference model. In the article “Adaptive Coordinated Reception for Multicell MIMO Uplink” by Lu et al. [2], power control and receive beamforming are jointly optimized with adaptive selection of multiple BSs to minimize the total transmit power, under individual signal-to-interferenceplus-noise ratio constraint per mobile station. To reduce the complexity in the large-scale cellular network, a suboptimal algorithm is derived, which exhibits a good trade-off between performance and complexity if the number of the pre-selected BSs is carefully chosen. In the article “Virtual Cooperation for Throughput Maximization in Distributed Large-Scale Wireless Networks” by Abouei et al. [3], a distributed wireless network with K links is con-sidered, where the links are partitioned into M clusters each operating in a subchannel with bandwidth W/M. The power allocation and number of clusters of such a network are optimized for maximization of the throughput as the number of links approaches infinity. In the article “Distributed Cooperative Precoding with Power Control for Cellular Systems with Correlated Antennas at the Receiver” by Vinosh Babu James et al. [4], the authors consider an analytical model for a multicell and multiuser system with receiver-side correlation. A distributed protocol for cooperation amongst the BSs is also proposed. System performance gains measured in terms of mean and cell-edge spectral efficiency values are reported. In the article “Multimode Transmission in Network MIMO Downlink with Incomplete CSI” by Seifi et al. [5], a two-step scheduling algorithm for a cooperative multicell MIMO downlink is proposed: in the first step, joint user and mode selection is performed, whereas, in the second step, feedback and precoder design is carried out by only considering the users selected in the first step. The metric used to perform user and mode * Correspondence: f.verde@unina.it Department of Biomedical, Electronic and Telecommunication Engineering (DIBET), University of Naples Federico II, Naples, Italy Full list of author information is available at the end of the article Verde et al. EURASIP Journal on Advances in Signal Processing 2012, 2012:41 http://asp.eurasipjournals.com/content/2012/1/41

다중 사용자 릴레이 시스템에서 감소된 피드백 정보를 이용한 두 단계 스케줄링 기법

In this paper, we introduce a multiuser (MU) scheduling method for multiuser amplify-and-forward relay systems, which selects both the transmission mode, i.e., either one- or two-hop transmission, and the desired user via two steps. A closed-form expression for the average achievable rate of the proposed scheduling is derived under two transmission modes with MU scheduling, and its asymptotic solution is also analyzed in the limit of large number of mobile stations. Based on the analysis, we perform our two-step scheduling algorithm: the transmission mode selection followed by the user selection that needs partial feedback for instantaneous signal-to-noise ratios (SNRs) to the base station. We also analyze the average SNR condition such that the MU diversity gain is fully exploited. In addition, it is examined how to further reduce a quantity of feedback under certain conditions. The proposed algorithm shows the comparable achievable rate to that of the optimal one using full feedback information, while its required feedback overhead is reduced below half of the optimal one.

Two-Step Fair Scheduling of Continuous Media Streams over Error-Prone Wireless Channels

In wireless cellular networks, streaming of continuous media (with strict QoS requirements) over wireless links is challenging due to their inherent unreliability characterized by location-dependent, bursty errors. To address this challenge, we present a two-step scheduling algorithm for a base station to provide streaming of continuous media to wireless clients over the error-prone wireless links. The proposed algorithm is capable of minimizing the packet loss rate of individual clients in the presence of error bursts, by transmitting packets in the round-robin manner and also adopting a mechanism for channel prediction and swapping.

A Two-Step Scheduling Algorithm to Support Dual Bandwidth Allocation Policies in an Ethernet Passive Optical Network

In this paper, we design a two-step scheduling algorithm to support multiple bandwidth allocation policies for upstream channel access in an Ethernet passive optical network. The proposed scheduling algorithm allows us a simultaneous approach for multiple access control policies: static bandwidth allocation for guaranteed bandwidth service and dynamic bandwidth allocation for on-demand, dynamic traffic services. In order to reduce the scheduling complexity, we separate the process of the transmission start- time decision from the process of grant generation. This technique does not require the timing information of other bandwidth allocation modules, so respective modules are free from a heavy amount of timing information or complex processing.