This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

Although cloud computing has rapidly emerged as a widely accepted computing paradigm, the research on cloud computing is still at an early stage. Cloud computing suffers from different challenging issues related to security, software frameworks, quality of service, standardization, and power consumption. Efficient energy management is one of the most challenging research issues. The core services in cloud computing system are the SaaS (Software as a Service), PaaS (Platform as a Service), and IaaS (Infrastructure as a Service). In this paper, we study state-of-the-art techniques and research related to power saving in the IaaS of a cloud computing system, which consumes a huge part of total energy in a cloud computing system. At the end, some feasible solutions for building green cloud computing are proposed. Our aim is to provide a better understanding of the design challenges of energy management in the IaaS of a cloud computing system.

State-of-the-art research study for green cloud computing

Fiber-Wireless (FiWi) network, as an integration of optical fiber network and wireless access network, has attracted intensive research interest and enjoyed significant growth in its applications over the last two decades. Besides bringing great opportunities for the development of FiWi networks, the new applications and techniques, like the emerging Internet of Things (IoT), raise unprecedented challenges in different aspects of FiWi integration. Based on such observation, we provide in this paper a comprehensive survey of recent progress and ongoing research works in the aspects of network architecture, QoS provisioning, scalability improving, reliability enhancing, energy saving, as well as standardization activities and case studies. Furthermore, new trends and challenging issues on future smart FiWi networks are identified and discussed in details.

New Perspectives on Future Smart FiWi Networks: Scalability, Reliability, and Energy Efficiency

Radio-over-fiber technology provides a simpler pathway for the distribution of wireless signals in broadband wireless networks via optical means. The technology has evolved over the last 30 years, with many challenges already overcome and with many more to address. This paper provides an overview of the technology evolutionary path of RoF with a review of its past, evaluation of its present, and a discussion of its challenges into the future.

Evolution of Radio-Over-Fiber Technology

Survivability is one of the key issues in hybrid wireless-optical broadband access networks (WOBAN) since the single segment failure can cause huge data loss The single segment failure refers to a scenario where all optical-network-units (ONUs) are disconnected with the optical line terminal (OLT) Previous schemes focus on protecting WOBAN against single segment failure by deploying backup fibers However, previous schemes suffer from two key problems First, they ignore optimizing the selection of backup ONUs, which determines the cost of recovering the traffic interrupted by the failure Second, they underutilize the residual capacity of segments, thus requiring higher backup fibers cost In this paper, we propose a new and efficient scheme, called Optimizing Backup ONUs selection and backup Fibers deployment (OBOF), to enhance the survivability of WOBAN against the single segment failure Our OBOF is composed of two consecutive steps, backup ONUs selection and backup fibers deployment In the first step, aiming to minimize the cost of recovering the traffic interrupted by the failure, the simulated annealing (SA) algorithm is customized to optimize the selection of backup ONUs In the second step, most importantly, an enhanced greedy cost-efficiency (EGCE) algorithm is proposed to optimize the deployment of backup fibers Our EGCE consists of a novel remote backup segment (RBS) method, which can efficiently utilize the residual capacity of the segments, and a Bound on Length of Backup-optical-path (BLB) method, which limits the increase in recovery time induced by RBS Extensive experimental results demonstrate that our OBOF scheme outperforms the previous schemes significantly, especially in the scenario of higher traffic demand

Optimizing Backup Optical-Network-Units Selection and Backup Fibers Deployment in Survivable Hybrid Wireless-Optical Broadband Access Networks

The integration of Ethernet Passive Optical Network (EPON) with IEEE 802.16 (WiMAX) is regarded as a promising access solution in realizing fixed mobile convergence (FMC) networks. The complementary features of EPON and WiMAX can bring not only wide bandwidth and mobility to subscriber stations (SS) but also economic efficiency to network providers. For successful convergence of EPON and WiMAX, there are some technical issues to resolve bandwidth allocation and QoS support in the MAC layer. Specifically, the independent scheduling (IS) mechanism to transmit data between EPON and WiMAX can cause performance degradation. For realizing EPON and WiMAX integration, this paper investigates three possible integrated architecture: independent ONU-BS (IOB), combined ONU-BS (COB), and hybrid ONU-BS (HOB). The emphasis on this paper is how to reduce the End-to-End (ETE) delay between EPON and WiMAX. For doing this, we propose a centralized scheduling (CS) mechanism that shortens the packet delay and the time of transmitting data upon requesting bandwidth for the SS. Simulation results witness that the proposed CS mechanism improves ETE delay, throughput, and QoS support compared to the IS when the cycle time of EPON and the frame size of WiMAX are 1 ms and 5 to 10 ms, as well as 2 ms and 5 ms, respectively.

Centralized Scheduling Mechanism for Enhanced End-to-End Delay and QoS Support in Integrated Architecture of EPON and WiMAX

Performance of the IEEE 802.16 e power management is mainly affected by two operating parameters: the minimum sleep interval (T min) and the maximum sleep interval (T max), in sleep-mode operation. To enhance the performance, this letter proposes a new power saving mechanism, which adaptively controls these parameters by considering the request period of each initiation of awakening (Tint)- The numerical analysis and simulation results show that this mechanism can achieve better energy conservation with reasonable response delay of Medium Access Control (MAC) Service Data Units (SDUs) than the standard operation.

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Adaptive power saving mechanism considering the request period of each initiation of awakening in the IEEE 802.16e system

A Power-Saving Mechanism (PSM) operates with sleep-mode and wake-mode, based on the receipt of requests for transition to each mode. The sleep-mode operation is manipulated by adjusting operating parameters such as the minimum sleep interval (Tmin) and the maximum sleep interval (Tmax). Interestingly, both energy consumption and the response delay of the request for a BS initiation of awakening are reciprocally affected by the relative sizes of these two operating parameters compared to the sleep duration (from the beginning of sleep-mode to that of wake-mode). To resolve this issue, this paper proposes a new PSM, called EPSM, which adaptively and simultaneously controls the operating parameters by efficiently reflecting the sleep duration. Moreover, depending on the current remaining energy state, this mechanism can also increase the available sizes of the operating parameters to be manipulated for achieving more intensive energy conservation. A numerical model is developed with a Markov chain for performance evaluation of the proposed mechanism pertaining to energy consumption and the response delay. The evaluation results substantiate that this mechanism can enhance energy conservation within reasonable response delay compared to the standard mechanism. Moreover, under an insufficient remaining energy state, the EPSM can prolong battery life while enduring an increasing response delay.

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Enhanced power-saving mechanism to maximize operational efficiency in IEEE 802.16e systems

The sleep mode operation is a significant part in power management in IEEE 802.16e for increasing life time of a station by saving energy consumption. In this operation, two key performance metrics, energy consumption and frame response delay, should be taken into account. These metrics are affected by initial sleep window (Tmin), final sleep window (Tmax), and average interarrival time (T1) of MAC frame to initiate awakening. Thus, this paper models the sleep mode operation in the IEEE 802.16e MAC and evaluates the effect of Tmin and Tmax on the performance of power management by considering T1. An analytical model for the operation is validated from computer simulation.

Performance Evaluation of the Sleep Mode Operation in the EEE 802.16e MAC

A mobile station in IEEE 802.16e operates power management using sleep-mode operation with one or more connections supporting several applications. After all of the connections of an MS transit into the sleep state, the MS powers down and then goes into an unavailable state without communicating with the serving base station. To improve energy conservation, this letter proposes a new scheduled power-saving mechanism, which schedules sleep-mode operations for connections, which newly initiate sleep-mode, by controlling operating parameters, such as the minimum sleep interval (Tmin) and the maximum sleep interval (Tmax), and the initiation time of sleepmode operations of low quality of service (QoS) connections. Performance results show that the proposed mechanism can reduce the available state of an MS through this scheduling, and thus achieve better energy conservation of the MS than the standard mechanism.

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JungYul Choi

Papers

Centralized Scheduling Mechanism for Enhanced End-to-End Delay and QoS Support in Integrated Architecture of EPON and WiMAX

Adaptive power saving mechanism considering the request period of each initiation of awakening in the IEEE 802.16e system

Enhanced power-saving mechanism to maximize operational efficiency in IEEE 802.16e systems

Performance Evaluation of the Sleep Mode Operation in the EEE 802.16e MAC

Scheduled power-saving mechanism to minimize energy consumption in IEEE 802.16e systems