It has been shown that quasi orthogonal space time block code (QOSTBC) can achieve high transmission rate with partial diversity. In this paper, a QOSTBC concatenating Bose-Chaudhuri-Hocquenghem (BCH) code structure i...It has been shown that quasi orthogonal space time block code (QOSTBC) can achieve high transmission rate with partial diversity. In this paper, a QOSTBC concatenating Bose-Chaudhuri-Hocquenghem (BCH) code structure is presented. At the receiver, pairwise detection and error correction are first implemented. The decoded data are regrouped. Parallel interference cancellation (PIC) and dual orthogonal space time block code (OSTBC) decoding are deployed to the regrouped data. The pure concatenated scheme is shown to have higher diversity order and better error performance at high signal-to-noise ratio (SNR) scenario than both QOSTBC and OSTBC schemes. The PIC and dual OSTBC decoding algorithm can further obtain approximate 1.2 dB gains than the pure concatenated scheme at 10-6 bit error probability.展开更多
In modern data centers, power consumed by network is an observable portion of the total energy budget and thus improving the energy efficiency of data center networks （DCNs） truly matters. One effective way for this...In modern data centers, power consumed by network is an observable portion of the total energy budget and thus improving the energy efficiency of data center networks （DCNs） truly matters. One effective way for this energy efficiency is to make the size of DCNs elastic along with traffic demands by flow consolidation and bandwidth scheduling, i.e., turning off unnecessary network components to reduce the power consumption. Meanwhile, having the instinct support for data center management, software defined networking （SDN） provides a paradigm to elastically control the resources of DCNs. To achieve such power savings, most of the prior efforts just adopt simple greedy heuristic to reduce computational complexity. However, due to the inherent problem of greedy algorithm, a good-enough optimization cannot be always guaranteed. To address this problem, a modified hybrid genetic algorithm （MHGA） is employed to improve the solution＇s accuracy, and the fine-grained routing function of SDN is fully leveraged. The simulation results show that more efficient power management can be achieved than the previous studies, by increasing about 5% of network energy savings.展开更多
In this paper, the average packet delay on IEEE 802.11 DCF under finite load traffic in multi-hop ad hoc networks is analyzed. We employ a Markov chain model to analyze the probability of transmission at each node in ...In this paper, the average packet delay on IEEE 802.11 DCF under finite load traffic in multi-hop ad hoc networks is analyzed. We employ a Markov chain model to analyze the probability of transmission at each node in an arbitrary slot and derive the channel access delay. We model each node using an M/G/1 queue and derive the queueing delay. The model is extended from analyzing the single-hop average packet delay to evaluating the end-to-end packet delay in multi-hop ad hoc networks without assuming the traffic to be in a saturation state. To validate our analytic results, we have done extensive simulation. The analytic and the simulation results match very well.展开更多
Providing quality of service （QoS） guarantees for multimedia applications over Hybrid networks by wired and wireless LANs is rapidly becoming an important issue. In order to protect the high priority traffic flows a...Providing quality of service （QoS） guarantees for multimedia applications over Hybrid networks by wired and wireless LANs is rapidly becoming an important issue. In order to protect the high priority traffic flows and improve network performance in a heavy-loaded network, a new dynamic admission control algorithm is proposed in this paper. We firstly propose a method to fit the fractional autoregressive integrated moving average （FARIMA） models to four actual wireless traffic traces and a traffic prediction based on the upper probability limit. Our experiments show that the one-step forecasts based on the FARIMA models are better than those based on autoregressive integrated moving average （ARIMA） models. We also propose a prediction-based admission control algorithm in hybrid QoS networks with WiFi access using the FARIMA models. The comprehensive simulation experiments are performed to verify the effectiveness of the proposed admission control algorithm.展开更多
基金National Natural Science Foundation of China(No.31003052)Henan University of Technology PhD Fund,China(No.2010BS025)
文摘It has been shown that quasi orthogonal space time block code (QOSTBC) can achieve high transmission rate with partial diversity. In this paper, a QOSTBC concatenating Bose-Chaudhuri-Hocquenghem (BCH) code structure is presented. At the receiver, pairwise detection and error correction are first implemented. The decoded data are regrouped. Parallel interference cancellation (PIC) and dual orthogonal space time block code (OSTBC) decoding are deployed to the regrouped data. The pure concatenated scheme is shown to have higher diversity order and better error performance at high signal-to-noise ratio (SNR) scenario than both QOSTBC and OSTBC schemes. The PIC and dual OSTBC decoding algorithm can further obtain approximate 1.2 dB gains than the pure concatenated scheme at 10-6 bit error probability.
基金supported by the Research Fund of Ministry of Education-China Mobile (MCM20160304)
文摘In modern data centers, power consumed by network is an observable portion of the total energy budget and thus improving the energy efficiency of data center networks （DCNs） truly matters. One effective way for this energy efficiency is to make the size of DCNs elastic along with traffic demands by flow consolidation and bandwidth scheduling, i.e., turning off unnecessary network components to reduce the power consumption. Meanwhile, having the instinct support for data center management, software defined networking （SDN） provides a paradigm to elastically control the resources of DCNs. To achieve such power savings, most of the prior efforts just adopt simple greedy heuristic to reduce computational complexity. However, due to the inherent problem of greedy algorithm, a good-enough optimization cannot be always guaranteed. To address this problem, a modified hybrid genetic algorithm （MHGA） is employed to improve the solution＇s accuracy, and the fine-grained routing function of SDN is fully leveraged. The simulation results show that more efficient power management can be achieved than the previous studies, by increasing about 5% of network energy savings.
基金the National Natural Science Foundation of China (Grant Nos. 60472078 and 90604013)
文摘In this paper, the average packet delay on IEEE 802.11 DCF under finite load traffic in multi-hop ad hoc networks is analyzed. We employ a Markov chain model to analyze the probability of transmission at each node in an arbitrary slot and derive the channel access delay. We model each node using an M/G/1 queue and derive the queueing delay. The model is extended from analyzing the single-hop average packet delay to evaluating the end-to-end packet delay in multi-hop ad hoc networks without assuming the traffic to be in a saturation state. To validate our analytic results, we have done extensive simulation. The analytic and the simulation results match very well.
基金the National Natural Science Foundation of China （Grant Nos. 60472078 and 90604013） a grant from the Cisco University Research Program Fund at Community Foundation Silicon Valley.
文摘Providing quality of service （QoS） guarantees for multimedia applications over Hybrid networks by wired and wireless LANs is rapidly becoming an important issue. In order to protect the high priority traffic flows and improve network performance in a heavy-loaded network, a new dynamic admission control algorithm is proposed in this paper. We firstly propose a method to fit the fractional autoregressive integrated moving average （FARIMA） models to four actual wireless traffic traces and a traffic prediction based on the upper probability limit. Our experiments show that the one-step forecasts based on the FARIMA models are better than those based on autoregressive integrated moving average （ARIMA） models. We also propose a prediction-based admission control algorithm in hybrid QoS networks with WiFi access using the FARIMA models. The comprehensive simulation experiments are performed to verify the effectiveness of the proposed admission control algorithm.
