The Experts below are selected from a list of 27351 Experts worldwide ranked by ideXlab platform
Petar Popovski - One of the best experts on this subject based on the ideXlab platform.
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generalized harq protocols with delayed channel state information and Average Latency constraints
IEEE Transactions on Information Theory, 2018Co-Authors: Kasper Floe Trillingsgaard, Petar PopovskiAbstract:In many wireless systems, the signal-to-interference-and-noise ratio that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid automatic repeat request (HARQ) protocols are often used to achieve high throughput with low Latency. This paper put forth the family of expandable message space (EMS) protocols, that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block-fading channel, the proposed EMS protocols are analyzed using dynamic programming. When full delayed CSIT is available and there is a constraint on the Average decoding time, it is shown that the optimal zero outage EMS protocol has a particularly simple operational interpretation and that the throughput is identical to that of the backtrack retransmission request (BRQ) protocol. We also devise EMS protocols for the case in which CSIT is only available through a finite number of feedback messages. The numerical results demonstrate that BRQ approaches the ergodic capacity quickly compared with HARQ, while EMS protocols with only three and four feedback messages achieve throughputs, that are only slightly worse than that of BRQ.
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generalized harq protocols with delayed channel state information and Average Latency constraints
arXiv: Information Theory, 2018Co-Authors: Kasper Floe Trillingsgaard, Petar PopovskiAbstract:In many wireless systems, the signal-to-interference-and-noise ratio that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid automatic repeat request (HARQ) protocols are often used to achieve high throughput with low Latency. This paper put forth the family of expandable message space (EMS) protocols that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block-fading channel, the proposed EMS protocols are analyzed using dynamic programming. When full delayed CSIT is available and there is a constraint on the Average decoding time, it is shown that the optimal zero outage EMS protocol has a particularly simple operational interpretation and that the throughput is identical to that of the backtrack retransmission request (BRQ) protocol. We also devise EMS protocols for the case in which CSIT is only available through a finite number of feedback messages. The numerical results demonstrate that the throughput of BRQ approaches the ergodic capacity quickly compared to HARQ, while EMS protocols with only three and four feedback messages achieve throughputs that are only slightly worse than that of BRQ.
Kun Wang - One of the best experts on this subject based on the ideXlab platform.
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low power low Latency optical network architecture for memory access communication
IEEE\ OSA Journal of Optical Communications and Networking, 2016Co-Authors: Yue Wang, Kang Wang, Yintang Yang, Kun WangAbstract:The interconnection network plays a vital role in improving the performance of modern computing systems. Traditional electronic interconnect is subject to Latency, power consumption, and bandwidth problems. A low-power low-Latency optical network architecture is proposed in this paper to interconnect cores and memory. The proposed architecture is made up of optical subnetworks using seven wavelengths. The optical subnetwork is constructed by some switching blocks, which are able to provide the memory access communication from all cores to ranks at the same time. Compared with traditional electronic bus-based core-to-memory architecture, the simulation results based on the PARSEC benchmark show that the Average Latency decreases by 54.05%, and the Average power consumption decreases by 86.25%. Due to the enhancement of parallel access, the total runtime of applications decreases by 66.43%.
Josep Paradells - One of the best experts on this subject based on the ideXlab platform.
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Overview and Evaluation of Bluetooth Low Energy: An Emerging Low-Power Wireless Technology
Sensors, 2012Co-Authors: Carles Gomez, J. Oller, Josep ParadellsAbstract:Bluetooth Low Energy (BLE) is an emerging low-power wireless technology developed for short-range control and monitoring applications that is expected to be incorporated into billions of devices in the next few years. This paper describes the main features of BLE, explores its potential applications, and investigates the impact of various critical parameters on its performance. BLE represents a trade-off between energy consumption, Latency, piconet size, and throughput that mainly depends on parameters such as connInterval and connSlaveLatency. According to theoretical results, the lifetime of a BLE device powered by a coin cell battery ranges between 2.0 days and 14.1 years. The number of simultaneous slaves per master ranges between 2 and 5,917. The minimum Latency for a master to obtain a sensor reading is 676 µs, although simulation results show that, under high bit error rate, Average Latency increases by up to three orders of magnitude. The paper provides experimental results that complement the theoretical and simulation findings, and indicates implementation constraints that may reduce BLE performance.
Haifeng Yang - One of the best experts on this subject based on the ideXlab platform.
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experimental demonstration of datacenter resources integrated provisioning over multi domain software defined optical networks
Journal of Lightwave Technology, 2015Co-Authors: Haoran Chen, Jie Zhang, Yongli Zhao, Junni Deng, Wei Wang, Haomian Zheng, Yi Lin, Haifeng YangAbstract:Due to the emergence of cloud computing and various cloud services which are remote and geographically distributed, datacenters interconnected by optical networks have attracted much attention of network operators and service providers. With the purpose of supporting cloud services more effectively and efficiently, IT resources and interconnected network resources provisioning could be considered in an orchestrated way. In this paper, we present a datacenter resources integrated provisioning (DRIP) architecture utilizing coordinated virtualization of distributed datacenters and operator's multi-domain software defined optical networks. The DRIP architecture aims to accomplish IT resources and optical network resources integrated allocation. In order to investigate the feasibility and efficiency of the proposed architecture, two IT resources allocation strategies and two virtual network composition strategies are evaluated on our testbed. We perform experimental demonstration to evaluate the strategies’ performance in terms of three metrics, i.e., CPU utilization ratio of physical hosts, virtual network failure rate, and Average Latency.
Kasper Floe Trillingsgaard - One of the best experts on this subject based on the ideXlab platform.
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generalized harq protocols with delayed channel state information and Average Latency constraints
IEEE Transactions on Information Theory, 2018Co-Authors: Kasper Floe Trillingsgaard, Petar PopovskiAbstract:In many wireless systems, the signal-to-interference-and-noise ratio that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid automatic repeat request (HARQ) protocols are often used to achieve high throughput with low Latency. This paper put forth the family of expandable message space (EMS) protocols, that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block-fading channel, the proposed EMS protocols are analyzed using dynamic programming. When full delayed CSIT is available and there is a constraint on the Average decoding time, it is shown that the optimal zero outage EMS protocol has a particularly simple operational interpretation and that the throughput is identical to that of the backtrack retransmission request (BRQ) protocol. We also devise EMS protocols for the case in which CSIT is only available through a finite number of feedback messages. The numerical results demonstrate that BRQ approaches the ergodic capacity quickly compared with HARQ, while EMS protocols with only three and four feedback messages achieve throughputs, that are only slightly worse than that of BRQ.
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generalized harq protocols with delayed channel state information and Average Latency constraints
arXiv: Information Theory, 2018Co-Authors: Kasper Floe Trillingsgaard, Petar PopovskiAbstract:In many wireless systems, the signal-to-interference-and-noise ratio that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid automatic repeat request (HARQ) protocols are often used to achieve high throughput with low Latency. This paper put forth the family of expandable message space (EMS) protocols that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block-fading channel, the proposed EMS protocols are analyzed using dynamic programming. When full delayed CSIT is available and there is a constraint on the Average decoding time, it is shown that the optimal zero outage EMS protocol has a particularly simple operational interpretation and that the throughput is identical to that of the backtrack retransmission request (BRQ) protocol. We also devise EMS protocols for the case in which CSIT is only available through a finite number of feedback messages. The numerical results demonstrate that the throughput of BRQ approaches the ergodic capacity quickly compared to HARQ, while EMS protocols with only three and four feedback messages achieve throughputs that are only slightly worse than that of BRQ.
