Browsing by Author "Huang, Ching-Yao"

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A Buffer Time based Call Admission Control Algorithm for Real-time Traffic in IEEE 802.11e WLAN
(2006)
Shih, Yuan-Hwai
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Huang, Ching-Yao
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The IEEE 802.11e introduces the Hybrid Coordination Function (HCF) to provide required mechanism fir supporting real-time services. In this paper, based on the calculated transition probability of a typical adaptive auto rate fallback (AARF) algorithm, a buffer-time (BT) based call admission control is proposed. Results show that the BT CAC not only utilizes the wireless resources more efficiently, but also satisfies the crucial QoS demanding for different real-time applications like video streaming and VoIP.
Analysis of Delay-Energy Tradeoff and Energy Minimization Schemes for Group-based Machine-to-Machine Communications in OFMDA Cellular Networks
(2012-01-01)
Ho, Chieh Yuan
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Huang, Ching-Yao
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Machine-to-Machine (M2M) communication has recently become a hot topic in 4G Standardization Committee, such as IEEE 802.16p and LTE-A. In an OFDMA cellular network embedded with a M2M system, we characterize system energy consumption (EC) and average delay for the M2M system and propose energy-efficient Machine Node (MN) access control schemes, jointly implementing MN grouping and coordinator selection, under a 2-hop transmission framework to minimize system EC with limited resource amount assigned by BS while satisfying the system delay requirement. In the simulation results, the tradeoff between EC and delay is investigated with respect to given resource amount, and the relationship between number of coordinators and total energy consumption is studied. Furthermore, the proposed schemes need relatively less coordinators to achieve very low EC, and can achieve near-optimal EC with any delay requirement.
Cross Layer Adaptation with QoS Guarantees for Wireless Scalable Video Streaming
(2012-09-01)
Lin, Hsuan-Li
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Wu, Tung-Yu
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Huang, Ching-Yao
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電機工程學系
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Department of Electrical and Computer Engineering
In this paper, a cross-layer adaptation scheme is proposed for quality of service (QoS) provision in the scalable video streaming of high definition (HD) content. The cross-layer parameters, which contain the video rate, payload length of a packet, the mode of modulation and coding scheme (MCS), can be dynamically adapted to minimize distortion of a video streaming under the given delay bound. Based on the channel quality and rate-distortion parameters, the proposed scheme formulates the problem of parameter selection into an optimization problem. Simulation results show that our approach guarantees video quality under QoS constraints.
Decomposing Data Analytics in Fog Networks
(2017-01-01)
Chang, Ta-Cheng
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Zheng, Liang
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Gorlatova, Maria
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Gitau, Chege
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Huang, Ching-Yao
Fog computing, the distribution of computing resources closer to the end devices along the cloud-to-things continuum, is recently emerging as an architecture for scaling of the Internet of Things (IoT) sensor networking applications. Fog computing requires novel computing program decompositions for heterogeneous hierarchical settings. To evaluate these new decompositions, we designed, developed, and instrumented a fog computing testbed that includes cloud computing and computing gateway execution points collaborating to finish complex data analytics operations. In this interactive demonstration we present one fog-specific algorithmic decomposition we recently examined and adapted for fog computing: a multi-execution point linear regression decomposition that jointly optimizes operation latency, quality, and costs. The demonstration highlights the role fog computing can play in future sensor networking architectures, and highlights some of the challenges of creating computing program decompositions for these architectures. An annotated video of the demonstration is available at [5].
DEVICE, METHOD AND SYSTEM FOR EXCHANGE OF INFORMATION BETWEEN MULTIPLE WIRELESS NETWORK GROUPS
(2010-07-22)
Cheng, Shih-Heng
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Huang, Ching-Yao
Exchanging information between multiple wireless network groups is implemented by a wireless channel with a wide transmission range and a wireless channel with a narrow transmission range so as to predetermine data transmission schedule of each node of the multiple wireless network groups. Hence, a drawback of the prior art, that is, reduced transmission efficiency and increased power consumption due to collisions between packets of the multiple wireless network groups, is overcome.
Energy Efficient Subcarrier-Power Allocation and Relay Selection Scheme for OFDMA-based Cooperative Relay Networks
(2011)
Ho, Chieh Yuan
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Huang, Ching-Yao
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電機工程學系
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Department of Electrical and Computer Engineering
uplink energy-efficient communication is an important issue due to the limited battery power for Mobile Stations (MSs). In this paper, the average 'Bits-per-Joule' is defined as the energy efficiency metric, and the optimal joint power allocation for both MS and RS is derived for maximizing MS' energy efficiency. Based on that, we developed a low-complexity subcarrier-power allocation and relay selection scheme for maximizing energy efficiency per user in an OFDMA cooperative relay network, assuming full channel state information (CSI) is available at both relay and BS nodes. The numerical result demonstrates that the energy efficiency performance of cooperative relay networks can be better in the range of 15% to 30% as compared to that of single BS networks. It also shows our proposed scheme has significant improvement on the energy efficiency performance as compared with conventional max-throughput and fairness-based Equal-Power Allocation (EPA) schemes which allocate equal transmit power to the assigned subcarriers. Furthermore, the proposed scheme can achieve similar performance in much lower computational complexity as compared with the exhaustive search scheme.
Energy-Efficient 2-D Resource Allocation with Fairness Constraints for OFDMA Networks
(2011)
Ho, Chieh Yuan
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Huang, Ching-Yao
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電機工程學系
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Department of Electrical and Computer Engineering
In this paper, a 2-Dimension (2-D) resource allocation problem for energy efficiency maximization in the uplink of an OFDMA network is studied. Firstly, with the metric of energy efficiency, measured as bits-per-joule, we convert the complex problem of optimizing the system energy efficiency, defined as sum of users' bits-per-joule, into an optimal achievable rate comparison problem, and devise a low-complexity sub-optimal resource allocation scheme for maximizing it while satisfying each user's resource requirement. The proposed scheme implements both power allocation and Resource Unit (RU) assignment devised by exploiting the optimal achievable rate maximizing user's energy efficiency. The numerical result shows that the proposed scheme outperforms widely-used schemes with Equal Power Allocation (EPA), such as maximum SNR and Proportional Fair, in terms of performance of bits-per-joule with different resource requirement and can achieve similar results as the exhaustive search scheme in much lower complexity.
Energy-Efficient Algorithms and Evaluations for Massive Access Management in Cellular Based Machine To Machine Communications
(2011)
Tu, Chih-Yuan
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Ho, Chieh-Yuan
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Huang, Ching-Yao
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電機工程學系
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Department of Electrical and Computer Engineering
As more and more machines are networked, machine-to-machine (M2M) communication have captured attention of IEEE 802.16 and 3GPP which, however, have only described possible system architecture, features, and issues, but no specification of M2M communication so far. Therefore, it is important for us to define the problems and provide solutions. Since most of the machine devices (MD) are battery equipped, and the number of MD is expected to be significantly more than human population, there are two critical requirements in M2M communications, low uplink energy consumption (EC) and massive access management. In this paper, we propose MD access control algorithms to ensure low uplink EC of M2M communication under the constraint of maximum number of access from MD to BS by implementing grouping and coordinator selection. Moreover, weighting factor which takes channel condition between the coordinator and base station (BS) into consideration is introduced to further improve EC performance. Numerical results show that our algorithms can not only achieve lower EC but also adapt to various distribution of MD.
Energy-Saving Massive Access Control and Resource Allocation Schemes for M2M Communications in OFDMA Cellular Networks
(2012-06)
Ho, Chieh Yuan
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Huang, Ching-Yao
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Machine-to-Machine communication recently becomes a popular issue in 4G Standardization Committee, such as IEEE 802.16p and LTE-A. In an OFDMA cellular network embedded with a M2M system, the energy consumption (EC) minimization problem is formulated with the consideration of transmission and circuit energy consumed. We propose joint massive access control and resource allocation (RA) schemes, which perform machine node grouping, coordinator selection, and coordinator RA, and also determine the proper number of groups under a 2-hop transmission protocol, to minimize total EC in both flat- and frequency-selective fading channel. Numerical results show that proposed schemes can achieve sub-optimal EC.
Non-Cooperative Multi-Cell Resource Allocation and Modulation Adaptation for Maximizing Energy Efficiency in Uplink OFDMA Cellular Networks
(2012-10)
Ho, Chieh Yuan
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Huang, Ching-Yao
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電機學院
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College of Electrical and Computer Engineering
We address the optimization problem of maximizing uplink energy efficiency, defined as sum of users bits-per-joule (bpj), in a multi-cell multi-user OFDMA network. Firstly, we propose a non-cooperative distributed scheme, in which mobile stations (MS) in different cells with given subcarrier assignment (SA) adjust the modulation and transmit power non-cooperatively, to optimize its own bpj. An advanced noncooperative BS-controlled resource allocation scheme, in which the base station in each cell jointly performs SA, modulation adaptation, and power control for MSs in a non-cooperative manner, is proposed. Numerical results illustrate the tradeoff between energy and spectral efficiency, and show the proposed scheme makes great improvement on bpj with marginal loss of throughput as compared to other conventional scheme.
OFDM Channel Prediction Using Fuzzy Update LMS Algorithm in Time-Variant Mobile Channel
(2006)
Wen, Jyh-Horng
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Chang, Cheih-Yao
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Lee, Gwo-Ruey
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Huang, Ching-Yao
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電子工程學系及電子研究所
Channel predictor implemented by discrete Fourier transform (DFT) is considered, which predict the channel gain of each receiving path by adaptive filters. A fuzzy logic controlled step size could overcome the drawback of conventional least-mean-square error (LMS) algorithm. In this paper, LMS algorithm with fuzzy updated step size is proposed to realize the adaptive channel prediction in orthogonal frequency division multiplexing (OFDM) systems. Simulation results show that as compared to conventional LMS algorithm, the proposed algorithm can achieve a faster convergence rate and lower steady-state mean square error. The proposed algorithm can also achieve more robust tracking ability in the various channel environments.
Payload Length Adaptation for Wireless Video Transmission in Multicarrier Systems
(2011)
Lin, Hsuan-Li
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Wu, Tung-Yu
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Huang, Ching-Yao
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電機工程學系
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Department of Electrical and Computer Engineering
We present an optimization architecture for a cross-layer design in wireless video transmission and investigate the multicarrier effect on wireless communication. To transmit video frames with delay bound and target frame error rate (FER) constraint, we formulate an optimization problem to minimize the required resource units for a single user by adjusting payload length, M-ary modulation, block size, and code rate. Instead of exhaustive approach, we propose a minimal required resource units (MRRU) algorithm with feedback of mean mutual information per bit (MMIB) to resolve this problem by binomial distribution function approximation. Finally, the performance comparison between MRRU algorithm and maximum throughput approach is given, and the effect on multicarrier system in a correlated Rayleigh fading channel is shown.
Resource provisioning towards OPEX optimization in horizontal edge federation
(2020-05-15)
Baghban, Hojjat
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Huang, Ching-Yao
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Hsu, Ching-Hsien
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電子工程學系及電子研究所
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電機工程學系
Energy consumption is a key performance metric in multi-access edge computing (MEC) system. Therefore, minimizing consumed energy cost is critically essential. The 5G networks deal with edge computing resources so that the operator would face with power supply limitation. Therefore, it may not be able to provide sufficient resources to ever-increasing user's requests. One way to compensate such limitation is to form horizontal edge federation (HEF) so that all participant can share the resource capacities as well as request workloads. Energy efficient and ultra-low latency HEF involves the setting of critical factor in each participant: offloading ratios. The decided offloading ratios must provide satisfactory service level to meet latency and physical resource types capacity constraints demanded by requests. Our proposed problem is an energy efficient operational cost (eOPEX) optimization problem. In this paper, we formulate it as a mixed integer linear program and demonstrate that the problem is NP-hard and proposed a federated multidimensional fractional knapsack based algorithm (FMFK) as our approach. The result shows that the horizontal edge federation based on the FMFK performs better and saves the more e-OPEX as well as serving more input requests compare with the non-federation approach. The experimental results show that our approach save about 40% of e-OPEX specially for high latency sensitive application requests in hotspot zone. It shows around 50% e-OPEX saving in the case of high computation unit cost compare with non-federation approach.
Single- and multi- user uplink energy-efficient resource allocation algorithms with users' power and minimum rate constraint in OFDMA cellular networks
(2013-07-01)
Ho, Chieh Yuan
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Huang, Ching-Yao
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper, single- and multi- user Resource Allocation (RA) optimization problems considering transmit power and minimum rate constraint of Mobile Station (MS) for maximizing MS' energy efficiency, measured as bits-per-joule (bpj), are addressed. Assume channel state information of all MSs is known by base station. We propose uplink RA algorithms, performing subcarrier assignment and power allocation, for optimizing bpj of MS in a single-cell OFDMA-based cellular network for both single- and multi- user scenarios. In the single-user case, we propose RA algorithms, which utilize the closed-form solution derived by applying Lambert-W function and an iterative approach based on Karush-Kuhn-Tucker conditions respectively to achieve optimal bpj of MS. In the multi-user case, centralized iterative multi-user RA algorithms for maximizing sum of MS' bpj, performing joint subcarrier assignment and power allocation iteratively, are proposed by utilizing the proposed single-user RA schemes. In particular, tradeoffs between energy efficiency and spectral efficiency are fully investigated, and the influence of MS' power and minimum rate constraints on bpj performance is also studied. The effectiveness of proposed algorithms is presented by numerical experiments. Numerical results demonstrate the proposed algorithms can enhance bpj significantly with limited loss of total throughput compared to the sum-rate maximization algorithm (in Moretti et al., IEEE Trans Veh Technol 60(4):1788-1798, 2011).
SOLID EARTH DEFORMATION MONITORING USING SATELLITE ALTIMETRY IN SOUTHWESTERN COASTS IN TAIWAN
(2010)
Cheng, Kai-chien
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Hwang, Cheinway
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Chung, Yu-Hsiang
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Huang, Ching-Yao
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Wei, Shiang-Hung
A novel method of using waveform retracked altimeter observations on land for the monitoring of the solid Earth deformation in Taiwan is described in the article. The southwestern coasts of Taiwan have been experiencing a significant land subsidence in the rate of similar to 8 cm/year, due to, in part, the excess extraction of the underground water. The first-order leveling networks and the GPS control points available in the area were used to verified the results of the waveform retracked altimeter observation. In this study, we proposed to use TOPEX/Poseidon (T/P) altimeter land observations from 1992-2002 on one T/P groundtrack that passes the southwestern coasts of Taiwan where is part of the Chia-Nan Plain with the main vegetation being rice paddy. This special vegetation and flat terrain provide an opportunity for successful waveform retracking. The comparison between T/P retracked result and that from the leveling network and GPS control points are presented.
Triggering and Relay Node Selection for Self-User Relaying
(2015-11-01)
Chou, Chie Ming
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Huang, Ching-Yao
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Self-user relaying technology is designed to support multiple self-owned devices especially when wearable devices are becoming more popular. In this letter, with a consideration of power control and discontinuous reception mechanism, a power model and energy metric are derived to analyze self-user relaying performance. Results show that under a typical traffic model, self-user relaying can improve energy performance when the relay node itself has the maximum traffic volume. Additionally, a simple battery budget threshold based relay node selection is suggested for limited battery budget of nodes.